U.S. patent application number 14/995133 was filed with the patent office on 2016-05-05 for image processing apparatus, image processing method, and image processing system.
The applicant listed for this patent is c/o SONY CORPORATION. Invention is credited to Daisuke Kikuchi, Hisakazu Shiraki, Hiromi Yoshinari.
Application Number | 20160125627 14/995133 |
Document ID | / |
Family ID | 50147991 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160125627 |
Kind Code |
A1 |
Kikuchi; Daisuke ; et
al. |
May 5, 2016 |
IMAGE PROCESSING APPARATUS, IMAGE PROCESSING METHOD, AND IMAGE
PROCESSING SYSTEM
Abstract
There is provided an image processing apparatus including a
processing unit configured to processes projection data in which
X-ray detection data representing a detection result of parallel
beam X-rays output from an X-ray source has been converted by
projection, and form an X-ray image based on the X-ray detection
data.
Inventors: |
Kikuchi; Daisuke; (Kanagawa,
JP) ; Yoshinari; Hiromi; (Kanagawa, JP) ;
Shiraki; Hisakazu; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
c/o SONY CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
50147991 |
Appl. No.: |
14/995133 |
Filed: |
January 13, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13968469 |
Aug 16, 2013 |
9239301 |
|
|
14995133 |
|
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Current U.S.
Class: |
382/132 |
Current CPC
Class: |
G01N 23/044 20180201;
G06T 11/006 20130101; G06T 7/0012 20130101; G01N 23/046 20130101;
G06T 2211/424 20130101; A61B 6/032 20130101; G06T 2207/10116
20130101 |
International
Class: |
G06T 11/00 20060101
G06T011/00; G06T 7/00 20060101 G06T007/00; A61B 6/03 20060101
A61B006/03; G01N 23/04 20060101 G01N023/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 24, 2012 |
JP |
2012-185292 |
Claims
1. An information processing apparatus comprising: circuitry
configured to: process projection data in which X-ray detection
data representing a detection result of X-ray beam output from an
X-ray source through a layer of a target has been converted by
projection; and form reconstruction data from the processed
projection data corresponding to the layer.
2. The information processing apparatus according to claim 1,
wherein the circuitry is configured to divide the projection data
and form the reconstruction data for each piece of the divided
projection data.
3. The information processing apparatus according to claim 1,
wherein the circuitry is configured to form an X-ray image based on
the reconstruction data each time the projection data is
acquired.
4. The information processing apparatus according to claim 1,
wherein the circuitry is configured to: detect the X-ray beam,
generate the X-ray detection data, and convert the generated X-ray
detection data into the projection data by projection, and process
the converted projection data.
5. The information processing apparatus according to claim 4,
wherein the circuitry is configured to: detect parallel X-ray beam
and generate the X-ray detection data based on the detected
parallel X-ray beam.
6. The information processing apparatus according to claim 4,
further comprising: an X-ray output unit that includes the X-ray
source for outputting the X-ray beam.
7. An information processing method comprising: processing
projection data in which X-ray detection data representing a
detection result of X-ray beam output from an X-ray source through
a layer of a target has been converted by projection and forming
reconstruction data from the projection data corresponding to the
layer.
8. An information processing system comprising: an X-ray output
apparatus that includes an X-ray source for outputting X-ray beam;
and circuitry configured to: detect X-ray beam, generate X-ray
detection data representing a detection result of the X-ray beam
through a layer of a target, and convert the generated X-ray
detection data corresponding to the layer into projection data by
projection; and process the projection data and form reconstruction
data from the projection data corresponding to the layer.
Description
CROSS REFERENCE RELATED APPLICATIONS
[0001] The present application is a Continuation application of
U.S. patent application Ser. No. 13/968,469 filed on Aug. 16, 2013
which claims priority to Japanese Patent Application No.
2012-185292 filed on Aug. 24, 2012, the disclosures of which are
incorporated herein by reference.
BACKGROUND
[0002] The present disclosure relates to an image processing
apparatus, an image processing method, and an image processing
system.
[0003] For example, a CT (computed tomography) apparatus (or a CT
system; hereinafter, the same) that utilizes X-rays output from an
X-ray source or an apparatus (or a system; hereinafter, the same)
having a tomosynthesis function that utilizes X-rays is widely used
in the medical field, for example. JP-A-2004-329784 describes a
technology relating to a CT apparatus that utilizes X-rays.
SUMMARY
[0004] A CT apparatus and the like that utilizes X-rays forms an
X-ray image by processing X-ray detection data representing a
detection result of X-rays. More specifically, in a CT apparatus
and the like that utilizes X-rays, an X-ray image is formed based
on X-ray detection data being converted into projection data, and
three-dimensional data being reconstituted from the projection
data, for example.
[0005] Here, in a CT apparatus and the like that utilizes X-rays,
an X-ray source that outputs cone beam X-rays is used, or an X-ray
source that outputs fan beam X-rays like the technology described
in JP-A-2004-329784 is used, for example.
[0006] However, when forming an X-ray image by processing
projection data in which X-ray detection data representing a result
that X-rays output from an X-ray source that outputs cone beam
X-rays or an X-ray source that outputs fan beam X-rays have been
detected has been converted, mixing of data of a plurality of
layers of a target that is hit by the X-rays occurs in the
projection data due to widening and unevenness of the detection
intensity resulting from the cone beam or the fan beam, for
example. Further, in order to strictly carry out the reconstitution
of three-dimensional data from projection data in which data from
various layers is mixed like this, calculations are performed that
repeatedly use all of the projection data and all of the
reconstitution data.
[0007] Therefore, to form an X-ray image having greater accuracy by
processing projection data in which X-ray detection data
representing a result that X-rays output from an X-ray source that
outputs cone beam X-rays or an X-ray source that outputs fan beam
X-rays have been detected has been converted, the calculation costs
for forming the X-ray image become very large.
[0008] Examples of methods for performing the calculations for
forming an X-ray image more rapidly include ignoring the effects
caused by a cone beam or a fan beam, or converting a cone beam or a
fan beam into a parallel beam in the projection data and dividing
the processing for forming the X-ray image.
[0009] However, when using such a method for performing the
calculations for forming an X-ray image more rapidly, since
approximate processing is included when forming the X-ray image,
the calculation accuracy deteriorates, so that the accuracy of the
obtained X-ray image deteriorates.
[0010] According to an embodiment of the present disclosure, there
are provided a novel and improved image processing apparatus, image
processing method, and image processing system that can achieve a
higher quality X-ray image while reducing the calculation costs for
reconstituting an X-ray image even further.
[0011] According to an embodiment of the present disclosure, there
is provided an image processing apparatus including a processing
unit configured to processes projection data in which X-ray
detection data representing a detection result of parallel beam
X-rays output from an X-ray source has been converted by
projection, and form an X-ray image based on the X-ray detection
data.
[0012] Further, according to an embodiment of the present
disclosure, there is provided an image processing method including
processing projection data in which X-ray detection data
representing a detection result of parallel beam X-rays output from
an X-ray source has been converted by projection, and forming an
X-ray image based on the X-ray detection data.
[0013] Further, according to an embodiment of the present
disclosure, there is provided an image processing system including
an X-ray output apparatus that includes an X-ray source for
outputting parallel beam X-rays, a detection apparatus configured
to detect the parallel beam X-rays, generate X-ray detection data
representing a detection result of the parallel beam X-rays, and
convert the generated X-ray detection data into projection data by
projection, and an image processing apparatus that includes a
processing unit configured to process projection data in which the
X-ray detection data has been converted, and form an X-ray image
based on the X-ray detection data.
[0014] According to the embodiments of the present disclosure
described above, a higher quality X-ray image can be achieved while
reducing the calculation costs for reconstituting an X-ray image
even further.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a flow diagram illustrating a first example of the
processing performed in an image processing method according to an
embodiment of the present disclosure performed by an image
processing apparatus according to an embodiment of the present
disclosure;
[0016] FIG. 2 is a flow diagram illustrating an example of
reconstitution processing performed by the image processing
apparatus according to an embodiment of the present disclosure;
[0017] FIG. 3 is an explanatory diagram illustrating the processing
performed in the image processing method according to an embodiment
of the present disclosure;
[0018] FIG. 4 is an explanatory diagram illustrating the processing
performed in the image processing method according to an embodiment
of the present disclosure;
[0019] FIG. 5 is an explanatory diagram illustrating the processing
performed in the image processing method according to an embodiment
of the present disclosure;
[0020] FIG. 6 is a flow diagram illustrating a second example of
the processing performed in the image processing method according
to an embodiment of the present disclosure performed by the image
processing apparatus according to an embodiment of the present
disclosure;
[0021] FIG. 7 is an explanatory diagram illustrating processing
performed in the image processing method according to an embodiment
of the present disclosure;
[0022] FIG. 8 is a flow diagram illustrating a third example of the
processing performed in the image processing method according to an
embodiment of the present disclosure performed by the image
processing apparatus according to an embodiment of the present
disclosure;
[0023] FIG. 9 is an explanatory diagram illustrating an example of
an image processing system according to an embodiment of the
present disclosure;
[0024] FIG. 10 is a block diagram illustrating an example of a
configuration of the image processing apparatus according to an
embodiment of the present disclosure; and
[0025] FIG. 11 is a diagram illustrating an example of a hardware
configuration of the image processing apparatus according to an
embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE EMBODIMENT(S)
[0026] Hereinafter, preferred embodiments of the present disclosure
will be described in detail with reference to the appended
drawings. Note that, in this specification and the appended
drawings, structural elements that have substantially the same
function and structure are denoted with the same reference
numerals, and repeated explanation of these structural elements is
omitted.
[0027] Further, the description will be made in the following
order.
1. Image processing method according to the present embodiment 2.
Image processing apparatus according to the present embodiment 3.
Program according to the present embodiment
(Image Processing Method According to the Present Embodiment)
[0028] Before describing the configuration of the image processing
apparatus according to the present embodiment, first, the image
processing method according to the present embodiment will be
described. In the following, the image processing method according
to the present embodiment will be described based on an example in
which the image processing apparatus according to the present
embodiment performs the processing performed in the image
processing method according to the present embodiment.
(1) Outline of the Image Processing Method According to the Present
Embodiment
[0029] As described above, when forming an X-ray image having
greater accuracy by processing projection data in which X-ray
detection data representing a result that X-rays output from an
X-ray source that outputs cone beam X-rays or an X-ray source that
outputs fan beam X-rays have been detected has been converted, the
calculation costs for forming the X-ray image become very large.
Further, when using the above-described method for performing the
calculations for forming an X-ray image more rapidly, since
approximate processing is included when forming the X-ray image,
the calculation accuracy deteriorates, so that the accuracy of the
obtained X-ray image deteriorates.
[0030] Accordingly, the image processing apparatus according to the
present embodiment forms an X-ray image based on X-ray detection
data by processing projection data in which X-ray detection data
representing a detection result of parallel beam X-rays output from
an X-ray source has been converted.
[0031] Here, the X-ray detection data according to the present
embodiment is, for example, data representing a detection intensity
of parallel beam X-rays that have passed through a target and have
been detected by a detector, such as the detector that is included
in the below-described detection apparatus according to the present
embodiment. In the following, to differentiate between the X-ray
detection data according to the present embodiment and the X-ray
detection data representing a detection result of cone beam X-rays
or fan beam X-rays, the X-ray detection data according to the
present embodiment is sometimes referred to as "parallel X-ray
detection data".
[0032] The parallel X-ray detection data representing the detection
intensity of the parallel beam X-rays detected by the
above-described detector is converted into projection data
(two-dimensional projection data) by being projected in two
dimensions as an X-ray projection image. More specifically, the
parallel X-ray detection data is converted into projection data by
radon conversion, for example.
[0033] Here, although the conversion processing for converting the
parallel X-ray detection data into projection data is performed by
an external device, such as the detection apparatus (described
below) according to the present embodiment, that generates the
X-ray detection data according to the present embodiment, for
example, the conversion processing according to the present
embodiment is not limited to being performed by an external device.
For example, the image processing apparatus according to the
present embodiment may perform the conversion processing according
to the present embodiment. In the following, the processing
performed in the image processing method according to the present
embodiment will be described mainly based on an example in which
the conversion processing according to the present embodiment is
performed by an external device, such as the detection apparatus
according to the present embodiment, that generates parallel X-ray
detection data, namely, a case in which the image processing
apparatus according to the present embodiment processes projection
data in which the parallel X-ray detection data has already been
converted by the external device.
[0034] Further, although the image processing apparatus according
to the present embodiment processes projection data in which
parallel X-ray detection data has been converted, or parallel X-ray
detection data, acquired from an external device such as the
below-described detection apparatus according to the present
embodiment, the projection data in which parallel X-ray detection
data has been converted or the parallel X-ray detection data
processed by the image processing apparatus according to the
present embodiment is not limited to that described above. For
example, the image processing apparatus according to the present
embodiment can also perform the processing by reading from a
storage unit (described below) projection data in which parallel
X-ray detection data has been converted, or parallel X-ray
detection data, that is stored in a storage unit (described below)
included in the apparatus (the image processing apparatus according
to the present embodiment) or stored on an external storage medium,
for example.
[0035] More specifically, the image processing apparatus according
to the present embodiment forms an X-ray image by reconstituting
three-dimensional data from the projection data.
[0036] Here, examples of the processing used by the image
processing apparatus according to the present embodiment to
reconstitute three-dimensional data from the projection data
include successive approximation methods, such as ML-EM (maximum
likelihood-expectation maximization), OS-EM (ordered
subsets-expectation maximization), and MAP-EM (maximum a
posteriori-expectation maximization). It is noted that the
processing performed to reconstitute three-dimensional data from
the projection data according to the present embodiment is
obviously not limited to processing that uses the successive
approximation methods mentioned above.
[0037] In processing using a successive approximation method like
those mentioned above, a value close to the correct value is
obtained by repeated projection of a reconstituted image and
reverse-projection of an image (corrected image) in which the
reconstituted image has been corrected. Therefore, the image
processing apparatus according to the present embodiment can form a
highly accurate X-ray image by performing processing that uses a
successive approximation method like those mentioned above as the
processing to reconstitute three-dimensional data from projection
data.
[0038] Therefore, the image processing apparatus according to the
present embodiment can achieve a higher quality X-ray image.
[0039] Further, as described above, the image processing apparatus
according to the present embodiment forms an X-ray image based on
parallel X-ray detection data by processing projection data in
which parallel X-ray detection data has been converted. Here, in
the projection data in which parallel X-ray detection data has been
converted, there is no mixing of the data of the plurality of
layers of the target, as is the case in the above-described
projection data in which X-ray detection data representing a
detection result of cone beam or fan beam X-rays has been
converted. This is because projection data in which parallel X-ray
detection data has been converted is not affected by the
above-described widening and unevenness of the detection intensity
resulting from a cone beam or a fan beam.
[0040] Therefore, by processing projection data in which parallel
X-ray detection data has been converted, the image processing
apparatus according to the present embodiment does not have to
perform processing to reduce the effects of a cone beam or a fan
beam, such as geometric correction, distortion correction, noise
removal and the like.
[0041] Accordingly, the image processing apparatus according to the
present embodiment can reduce the calculation costs for forming an
X-ray image more than when processing the above-described X-ray
detection data that represents a detection result of cone beam or
fan beam X-rays.
[0042] Further, since the image processing apparatus according to
the present embodiment does not have to perform processing to
reduce the effects of a cone beam or a fan beam, such as geometric
correction, distortion correction, noise removal and the like,
approximation or image deterioration resulting from processing to
reduce the effects of a cone beam or a fan beam is prevented.
Therefore, the image processing apparatus according to the present
embodiment can achieve a higher quality X-ray image.
[0043] In addition, by processing projection data in which parallel
X-ray detection data has been converted, since there is no mixing
of the data of the respective layers of the target in the
projection data, deterioration in the accuracy of the X-ray image
is prevented even if the image processing apparatus according to
the present embodiment processes only the parallel X-ray detection
data corresponding to a specific layer of the target. Namely, by
processing projection data in which parallel X-ray detection data
has been converted, with the image processing apparatus according
to the present embodiment it is possible to process only the
parallel X-ray detection data corresponding to a specific layer of
the target.
[0044] Therefore, the image processing apparatus according to the
present embodiment is capable of performing processing (e.g.,
processing for dividing the projection data and forming an X-ray
image for each piece of divided projection data (described below))
in parallel. Further, since the image processing apparatus
according to the present embodiment can form successive X-ray
images each time projection data is acquired (described below), for
example, the amount of memory that is used in one calculation is
substantially reduced.
(2) Processing Performed in the Image Processing Method According
to the Present Embodiment
[0045] Next, the processing performed in the image processing
method according to the present embodiment will be described in
more detail.
[0046] In the following, the processing performed in the image
processing method according to the present embodiment will be
described based on an example in which the image processing
apparatus according to the present embodiment processes projection
data in which parallel X-ray detection data has been converted by
an external device. It is noted that when the image processing
apparatus according to the present embodiment processes parallel
X-ray detection data, the image processing apparatus according to
the present embodiment converts the parallel X-ray detection data
into projection data, for example, and processes the converted
projection data.
(2-1) First Example of the Processing Performed in the Image
Processing Method According to the Present Embodiment
[0047] FIG. 1 is a flow diagram illustrating a first example of the
processing performed in an image processing method according to the
present embodiment performed by an image processing apparatus
according to the present embodiment.
[0048] The image processing apparatus according to the present
embodiment determines whether projection data has been acquired
(S100). The image processing apparatus according to the present
embodiment determines that projection data has been acquired if all
of the projection data corresponding to the target has been read
into a RAM (random-access memory), for example.
[0049] If it is determined in step S100 that projection data has
not been acquired, the image processing apparatus according to the
present embodiment does not proceed to the next processing step
until projection data is acquired.
[0050] Further, if it is determined in step S100 that projection
data has been acquired, the image processing apparatus according to
the present embodiment sets the image represented by the projection
data as projection image P, and sets an initial reconstituted image
I.sub.0 (S102).
[0051] Here, although the image processing apparatus according to
the present embodiment sets the initial reconstituted image I.sub.0
by generating as the initial reconstituted image I.sub.0 an image
in which the pixel values of all of the pixels are positive, such
as an image in which the pixel values of all of the pixels are
indicated as "1", for example, the processing for setting the
initial reconstituted image I.sub.0 that is performed in the
present embodiment is not limited to this. For example, in order to
complete the below-described reconstitution processing more
rapidly, the image processing apparatus according to the present
embodiment may set an image reconstituted by a FBP (filtered
back-projection) method as the initial reconstituted image I.sub.0.
Further, the image processing apparatus according to the present
embodiment can also, for example, set an arbitrary image in which
the pixel values are positive as the initial reconstituted image
I.sub.0.
[0052] When the processing of step S102 has been performed, the
image processing apparatus according to the present embodiment
performs reconstitution processing for forming an X-ray image
(S104).
[0053] FIG. 2 is a flow diagram illustrating an example of
reconstitution processing performed by the image processing
apparatus according to the present embodiment.
[0054] The image processing apparatus according to the present
embodiment projects a reconstituted image I.sub.n (wherein n
denotes an integer of 0 or more), and generates a reprojection
image P' (S200). Here, the reconstituted image I.sub.n that is
initially projected by the image processing apparatus according to
the present embodiment is the initial reconstituted image I.sub.0
set in step S102 of FIG. 1.
[0055] When the processing of step S200 has been performed, the
image processing apparatus according to the present embodiment
compares the reprojection image P' and the projection image P, for
example, and calculates a ratio between the reprojection image P'
and the projection image P (S202).
[0056] When the ratio between the reprojection image P' and the
projection image P has been calculated in step S202, the image
processing apparatus according to the present embodiment determines
whether to finish the reconstitution processing (S204). The image
processing apparatus according to the present embodiment determines
that the reconstitution processing is to be finished when, for
example, the ratio between the reprojection image P' and the
projection image P calculated in step S202 is equal to or less than
a predetermined set value (or less than a predetermined value).
[0057] If it is not determined in step S204 to finish the
reconstitution processing, the image processing apparatus according
to the present embodiment reverse-projects the reprojection image
P' (correction value) using the ratio between the reprojection
image P' and the projection image P to generate a new reconstituted
image I.sub.n (n=n+1) (S206). Then, the image processing apparatus
according to the present embodiment repeats the processing from
step S200.
[0058] Further, if it is determined in step S204 to finish the
reconstitution processing, the image processing apparatus according
to the present embodiment sets the reconstituted image I.sub.n as
the X-ray image (a so-called reconstituted layer image) (S208).
Then, the image processing apparatus according to the present
embodiment finishes the reconstitution processing.
[0059] The image processing apparatus according to the present
embodiment performs the processing illustrated in FIG. 2, for
example, as the reconstitution processing according to the present
embodiment.
[0060] Here, when the image processing apparatus according to the
present embodiment uses ML-EM, which is a basic successive
approximation method that uses maximum likelihood estimation, the
reconstitution processing according to the present embodiment is
represented by the following formula 1, for example.
.lamda. j ( k + 1 ) = .lamda. j ( k ) i = 1 n C ij i = 1 n y i C ij
j ' = 1 m C ij ' .lamda. j ' ( k ) ( Formula 1 ) ##EQU00001##
[0061] The "i" in formula 1 represents the coordinates of the
reconstituted image I.sub.n (the coordinates corresponding to the
position of the target), the "j" in formula 1 represents the
coordinates of the projection image P, and the "k" in formula 1
represents the number of repetitions. Further, the "C.sub.ij" in
formula 1 represents the "detection rate", which is the probability
of the voxel of coordinate i in the target being detected by a
detector corresponding to coordinate j of the projection image
P.
[0062] Therefore, for example, to reconstitute a given layer by a
successive approximation method, one calculation cycle can be
carried out by plugging all of the voxels of that layer and the
values of the detection positions corresponding to those voxels.
Accordingly, when reconstituting an X-ray image corresponding to a
three-dimensional object (target), the reconstituted image I.sub.n
and the projection image P based on the projection data are
three-dimensional, so that the calculation represented in formula 1
can be carried out on all of the voxels in three dimensions.
[0063] FIG. 3 is an explanatory diagram illustrating the processing
performed in the image processing method according to the present
embodiment. FIG. 3 illustrates an example in a typical CT of the
correspondence among the position of the X-ray source, the position
of the target through which the X-rays pass, and the position of
the detector. Symbol A in FIG. 3 illustrates an example in a
single-slice type CT apparatus of the correspondence among the
position of the X-ray source, the position of the target through
which the X-rays pass, and the position of the detector. Further,
symbol B in FIG. 3 illustrates an example in a multi-slice type CT
apparatus of the correspondence among the position of the X-ray
source, the position of the target through which the X-rays pass,
and the position of the detector.
[0064] For the single-slice type CT apparatus illustrated by A in
FIG. 3, since one layer and one array of detectors correspond to
each other on a one-to-one basis, the successive calculations
performed in the above reconstitution processing can be performed
layer by layer. Namely, in the case of the single-slice type CT
apparatus illustrated by A in FIG. 3, in formula 1 a
two-dimensional.times.two-dimensional calculation can be performed.
Therefore, when reconstituting the X-ray image using the
single-slice type CT apparatus illustrated by A in FIG. 3, the
calculation costs to form the X-ray image are smaller than the
calculation costs to form the X-ray image when reconstituting an
X-ray image using the multi-slice type CT apparatus employing an
X-ray source that outputs cone beam X-rays like that illustrated by
B in FIG. 3. However, with the single-slice type CT apparatus
illustrated by A in FIG. 3, the larger the detection area of the
target, the longer it takes to generate the X-ray image.
[0065] Further, for recent CT apparatuses, in order to increase the
detection area and shorten the time, a multi-slice type like that
illustrated by B in FIG. 3 is mainstream. Here, for a multi-slice
type CT apparatus, an X-ray source that outputs cone beam X-rays is
used, as illustrated by B of FIG. 3.
[0066] When an X-ray source that outputs cone beam X-rays is used
as illustrated by B of FIG. 3, when an attempt is made to
reconstitute the X-ray image corresponding to a given layer, the
width of the detector corresponding to the X-rays that pass through
that layer surface increases. In addition, when the X-ray source
and the detector are rotated by a gantry and the like configuring
the CT apparatus, the position of the detector that passes through
a given voxel of the target changes depending on the angle of
rotation.
[0067] Therefore, when an X-ray source that outputs cone beam
X-rays is used as illustrated by B of FIG. 3, when reconstituting
the X-ray image corresponding to the layer surface, all of the
relevant voxels and the detectors are used in the calculation.
Namely, when reconstituting an X-ray image using an X-ray source
that outputs cone beam X-rays as illustrated by B of FIG. 3, all of
the voxels and the detectors that have an effect on each other are
used in all the calculations even when trying to reconstitute the
X-ray image corresponding to a given specific layer surface.
[0068] Therefore, when reconstituting an X-ray image using an X-ray
source that outputs cone beam X-rays as illustrated by B of FIG. 3,
the value of all the voxels in the three-dimensional information
about the target and the value of all the detectors are used in a
given single calculation. Namely, when reconstituting an X-ray
image using an X-ray source that outputs cone beam X-rays as
illustrated by B of FIG. 3, the calculation amount of the detection
probability C.sub.ij in formula 1 increases.
[0069] FIG. 4, which is an explanatory diagram illustrating the
processing performed in the image processing method according to
the present embodiment, illustrates the outline of the processing
that is performed when reconstituting an X-ray image using a cone
beam X-ray source.
[0070] As illustrated in FIG. 4, when reconstituting an X-ray image
using an X-ray source that outputs cone beam X-rays as illustrated
by B of FIG. 3, correspondence between three-dimensional
data.times.three-dimensional data is repeatedly calculated based on
formula 1. Therefore, when reconstituting an X-ray image using an
X-ray source that outputs cone beam X-rays as illustrated by B of
FIG. 3, the calculation amount is very large. Further, even when
reconstituting an X-ray image using a fan beam X-ray source,
similar to when reconstituting an X-ray image using an X-ray source
that outputs cone beam X-rays as illustrated by B of FIG. 3, the
calculation amount relating to the reconstitution of the X-ray
image is very large.
[0071] Therefore, as described above, when forming an X-ray image
having greater accuracy by processing projection data in which
X-ray detection data representing a result that X-rays output from
an X-ray source that outputs cone beam X-rays or an X-ray source
that outputs fan beam X-rays have been detected has been converted,
the calculation costs for forming the X-ray image become very
large.
[0072] FIG. 5, which is an explanatory diagram illustrating
processing performed in the image processing method according to
the present embodiment, illustrates an example of a multi-slice
type CT apparatus in which an X-ray source that outputs parallel
beam X-rays is used.
[0073] As illustrated in FIG. 5, when an X-ray source that outputs
parallel beam X-rays is used, since X-rays are irradiated from an
X-ray source parallel to the array of detectors, mixing of the
layer data among the layers is eliminated, so that each
cross-section and each detector array are independent, and the
correspondence between the cross-sections and the detectors is on a
one-to-one basis. Further, as described above, the image processing
apparatus according to the present embodiment forms an X-ray image
based on X-ray detection data by processing projection data in
which X-ray detection data representing a detection result of
parallel beam X-rays output from an X-ray source has been
converted.
[0074] Therefore, in the reconstitution processing according to the
present embodiment illustrated in FIG. 2, the image processing
apparatus according to the present embodiment can perform the
successive calculations for reconstitution on a per layer basis in
a closed state. Further, since the reconstitution calculations are
also two-dimensional.times.two-dimensional, the calculation amount
that is performed in one go can be substantially reduced. In
addition, the calculation amount of the detection probability
C.sub.ij in formula 1 can be reduced by a lot more than when
reconstituting an X-ray image using an X-ray source that outputs
cone beam X-rays as illustrated by B of FIG. 3, for example.
[0075] The image processing apparatus according to the present
embodiment performs the processing illustrated in FIG. 1, for
example, as the processing performed in the image processing method
according to the present embodiment.
[0076] Here, in the projection data in which parallel X-ray
detection data has been converted that is processed by the image
processing apparatus according to the present embodiment in the
processing illustrated in FIG. 1, there is no mixing of data of the
plurality of layers of the target, as is the case with the
above-described projection data in which X-ray detection data
representing a detection result of cone beam or fan beam X-rays has
been converted. Namely, when performing the processing illustrated
in FIG. 1, for example, the image processing apparatus according to
the present embodiment does not have to perform processing to
reduce the effects of a cone beam or a fan beam, such as geometric
correction, distortion correction, noise removal and the like.
Further, the calculation amount relating to the reconstitution
processing performed by the image processing apparatus according to
the present embodiment is reduced by a lot more than when
processing the above-described projection data in which X-ray
detection data representing a detection result of cone beam or fan
beam X-rays has been converted. Therefore, when performing the
processing illustrated in FIG. 1, for example, deterioration
resulting from the processing to reduce the effects of a cone beam
or a fan beam is prevented. Further, the calculation costs for
forming an X-ray image can be reduced more than when processing the
above-described X-ray detection data that represents a detection
result of cone beam or fan beam X-rays. Therefore, by performing
the processing illustrated in FIG. 1, for example, the image
processing apparatus according to the present embodiment can
achieve a higher quality X-ray image while reducing the calculation
costs for forming an X-ray image even further.
[0077] Further, for example, in the processing illustrated in FIG.
1, the image processing apparatus according to the present
embodiment performs processing that uses a successive approximation
method, such as processing using the ML-EM method represented in
formula 1, for example, as the reconstitution processing for
forming an X-ray image. Therefore, since a highly accurate X-ray
image can be formed by performing the processing illustrated in
FIG. 1, for example, a higher quality X-ray image can be
achieved.
[0078] It is noted that the processing performed in the image
processing method according to the present embodiment that is
performed by the image processing apparatus according to the
present embodiment is not limited to the processing according to
the first example illustrated in FIG. 1.
[0079] As described above, by processing projection data in which
parallel X-ray detection data has been converted, there is no
mixing in the projection data of the data from respective layers in
the target. Therefore, a deterioration in the accuracy of the X-ray
image is prevented even if the image processing apparatus according
to the present embodiment processes only the parallel X-ray
detection data corresponding to a specific layer of the target.
Namely, by processing projection data in which parallel X-ray
detection data has been converted, with the image processing
apparatus according to the present embodiment it is possible to
process only the parallel X-ray detection data corresponding to a
specific layer of the target.
[0080] Therefore, the image processing apparatus according to the
present embodiment can, for example, divide the projection data and
form an X-ray image for each piece of divided projection data (the
parallel processing according to the present embodiment). Further,
the image processing apparatus according to the present embodiment
can also form successive X-ray images each time projection data is
acquired (the successive processing according to the present
embodiment).
(2-2) Second Example of the Processing Performed in the Image
Processing Method According to the Present Embodiment
[0081] FIG. 6 is a flow diagram illustrating a second example of
the processing performed in the image processing method according
to the present embodiment by the image processing apparatus
according to the present embodiment. Here, FIG. 6 illustrates an
example of the parallel processing according to the present
embodiment.
[0082] Similar to step S100 of FIG. 1, the image processing
apparatus according to the present embodiment determines whether
projection data has been acquired (S300). If it is determined in
step S300 that projection data has not been acquired, the image
processing apparatus according to the present embodiment does not
proceed to the next processing step until projection data is
acquired.
[0083] Further, if it is determined in step S300 that projection
data has been acquired, the image processing apparatus according to
the present embodiment divides the projection data (S302). Here
although the image processing apparatus according to the present
embodiment divides the projection data on a per layer basis, for
example, the units that the image processing apparatus according to
the present embodiment divides the projection data into are not
especially limited. Further, the units into which the image
processing apparatus according to the present embodiment divides
the projection data may be, for example, a single unit, or a
mixture of a plurality of units. The image processing apparatus
according to the present embodiment sets an image represented by
each piece of divided projection data as the projection image
P.
[0084] Further, if it is determined in step S300 that projection
data has been acquired, the image processing apparatus according to
the present embodiment sets an initial reconstituted image I.sub.0
corresponding to each piece of divided projection data (S304).
Here, the image processing apparatus according to the present
embodiment sets the initial reconstituted image I.sub.0 in the same
manner as in step S102 of FIG. 1.
[0085] It is noted that although in FIG. 6 an example is
illustrated in which the processing of step S304 is carried out
after the processing step S302, the processing of step S302 and the
processing step S304 can be performed independently. Therefore, the
image processing apparatus according to the present embodiment can
perform the processing of step S302 and the processing step S304 in
synchronization, for example.
[0086] When the processing steps S302 and S304 has been performed,
the image processing apparatus according to the present embodiment
performs in parallel the reconstitution processing for forming an
X-ray image for each piece of divided projection data (S306). Here,
the image processing apparatus according to the present embodiment
performs the reconstitution processing for forming X-ray images in
the same manner as in step S104 of FIG. 1, for example.
[0087] The image processing apparatus according to the present
embodiment performs the processing illustrated in FIG. 6, for
example, as the processing performed in the image processing method
according to the present embodiment.
[0088] Here, in the projection data that is processed by the image
processing apparatus according to the present embodiment in the
processing illustrated in FIG. 6, similar to the processing
according to the first example illustrated in FIG. 1, there is no
mixing of data of the plurality of layers of the target. Namely,
similar to the processing according to the first example
illustrated in FIG. 1, when performing the processing illustrated
in FIG. 6, for example, the image processing apparatus according to
the present embodiment does not have to perform processing to
reduce the effects of a cone beam or a fan beam, such as geometric
correction, distortion correction, noise removal and the like.
Further, similar to the processing according to the first example
illustrated in FIG. 1, the calculation amount relating to the
reconstitution processing performed by the image processing
apparatus according to the present embodiment is reduced by a lot
more than when processing the above-described projection data in
which X-ray detection data representing a detection result of cone
beam or fan beam X-rays has been converted.
[0089] Therefore, similar to the processing according to the first
example illustrated in FIG. 1, by performing the processing
illustrated in FIG. 6, for example, the image processing apparatus
according to the present embodiment can achieve a higher quality
X-ray image while reducing the calculation costs for forming an
X-ray image even further.
[0090] Further, in the processing illustrated in FIG. 6, the
dividing of the projection data into respective layers and the
reconstitution processing corresponding to each piece of projection
data are performed in parallel.
[0091] Therefore, the image processing apparatus according to the
present embodiment can shorten the processing time (calculation
time) taken for the reconstitution processing more than when an
X-ray image is reconstituted using an X-ray source that outputs
cone beam or fan beam X-rays, for example. In addition, similar to
the processing according to the first example illustrated in FIG.
1, since there is no mixing of the data of the plurality of layers
of the target in the projection data processed by the image
processing apparatus according to the present embodiment,
deterioration in the accuracy of the X-ray image is prevented even
if the image processing apparatus according to the present
embodiment processes only the parallel X-ray detection data
corresponding to a specific layer of the target.
(2-3) Third Example of the Processing Performed in the Image
Processing Method According to the Present Embodiment
[0092] FIG. 7 is an explanatory diagram illustrating the processing
performed in the image processing method according to the present
embodiment. FIG. 7 illustrates an example in a helical scanning
type CT apparatus, or in a non-helical scanning type CT apparatus,
for example, of the correspondence among the position of the X-ray
source, the position of the target through which the X-rays pass,
and the position of the detector. Further, a person is shown in
FIG. 7 as the target.
[0093] In a helical scanning type CT apparatus or a non-helical
scanning type CT apparatus like that illustrated in FIG. 7, when an
X-ray source that outputs cone beam X-rays is used as illustrated
by B of FIG. 3, reconstitution processing like that illustrated in
FIG. 2 is not performed until all of the scans of the target are
finished. This is because, as described above, when reconstituting
an X-ray image using an X-ray source that outputs cone beam X-rays,
all of the voxels and the detectors that have an effect on each
other are used in all the calculations even when trying to
reconstitute the X-ray image corresponding to a given specific
layer surface.
[0094] In contrast, in the projection data in which parallel X-ray
detection data has been converted that is processed by the image
processing apparatus according to the present embodiment, there is
no mixing of data of the plurality of layers of the target, as is
the case with the above-described projection data in which X-ray
detection data representing a detection result of cone beam or fan
beam X-rays has been converted. Therefore, as described above, a
deterioration in the accuracy of the X-ray image is prevented even
if the image processing apparatus according to the present
embodiment processes only the parallel X-ray detection data
corresponding to a specific layer of the target. Namely, a
deterioration in the accuracy of the X-ray image to be formed does
not occur even if successive X-ray images are formed each time
projection data is acquired, for example.
[0095] Accordingly, as the processing according to the third
example of the image processing method according to the present
embodiment, an example will be described of processing that can
realize the successive processing according to the present
embodiment.
[0096] FIG. 8 is a flow diagram illustrating a third example of the
processing performed in the image processing method according to
the present embodiment performed by the image processing apparatus
according to present embodiment. Here, FIG. 8 illustrates an
example of the successive processing according to the present
embodiment.
[0097] The image processing apparatus according to the present
embodiment determines whether projection data has been acquired
(S400). The image processing apparatus according to the present
embodiment determines that projection data has been acquired if
projection data transmitted from an external device has been
received, and the received projection data read into the RAM or the
like, or if projection data stored in a storage unit (described
below) has been read from the storage unit (described below), and
the read projection data read into the RAM or the like, for
example.
[0098] If it is determined in step S400 that projection data has
not been acquired, the image processing apparatus according to the
present embodiment does not proceed to the next processing step
until projection data is acquired.
[0099] Further, if it is determined in step S400 that projection
data has been acquired, the image processing apparatus according to
the present embodiment sets an initial reconstituted image I.sub.0
in the same manner as in step S102 of FIG. 1 (S402).
[0100] When the processing step S402 has been performed, the image
processing apparatus according to the present embodiment performs
the reconstitution processing for forming an X-ray image in the
same manner as in step S104 of FIG. 1 (S404).
[0101] When the processing step S404 has been performed, the image
processing apparatus according to the present embodiment determines
whether to finish the processing performed in the image processing
method according to the present embodiment (S406). Here, when
processing projection data based on parallel X-ray detection data
representing a detection result in a helical scanning type CT
apparatus or a non-helical scanning type CT apparatus like that
illustrated in FIG. 7, the image processing apparatus according to
the present embodiment determines, for example, to finish the
processing performed in the image processing method according to
the present embodiment when a signal indicating that scanning has
finished transmitted from an external device, such as the CT
apparatus, is received. Further, if projection data stored in a
storage unit (described below) or the like is processed, the image
processing apparatus according to the present embodiment determines
to finish the processing performed in the image processing method
according to the present embodiment when, for example, all of
projection data (e.g., projection data formed into groups based on
metadata and the like) corresponding to a given target has been
read from the storage unit (described below).
[0102] If it is not determined in step S406 to finish the
processing performed in the image processing method according to
the present embodiment, the image processing apparatus according to
the present embodiment repeats the processing from step S400.
Further, if it is determined in step S406 to finish the processing
performed in the image processing method according to the present
embodiment, the image processing apparatus according to the present
embodiment finishes the processing performed in the image
processing method according to the present embodiment.
[0103] The image processing apparatus according to the present
embodiment performs the processing illustrated in FIG. 8, for
example, as the processing performed in the image processing method
according to the present embodiment.
[0104] Here, in the projection data that is processed by the image
processing apparatus according to the present embodiment in the
processing illustrated in FIG. 8, similar to the processing
according to the first example illustrated in FIG. 1, there is no
mixing of data of the plurality of layers of the target. Namely,
similar to the processing according to the first example
illustrated in FIG. 1, when performing the processing illustrated
in FIG. 8, for example, the image processing apparatus according to
the present embodiment does not have to perform processing to
reduce the effects of a cone beam or a fan beam, such as geometric
correction, distortion correction, noise removal and the like.
Further, similar to the processing according to the first example
illustrated in FIG. 1, the calculation amount relating to the
reconstitution processing performed by the image processing
apparatus according to the present embodiment is reduced by a lot
more than when processing the above-described projection data in
which X-ray detection data representing a detection result of cone
beam or fan beam X-rays has been converted.
[0105] Therefore, similar to the processing according to the first
example illustrated in FIG. 1, by performing the processing
illustrated in FIG. 8, for example, the image processing apparatus
according to the present embodiment can achieve a higher quality
X-ray image while reducing the calculation costs for forming an
X-ray image even further.
[0106] In addition, similar to the processing according to the
first example illustrated in FIG. 1, since there is no mixing of
the data of the plurality of layers of the target in the projection
data processed by the image processing apparatus according to the
present embodiment, deterioration in the accuracy of the X-ray
image is prevented even if only the parallel X-ray detection data
corresponding to a specific layer of the target is processed.
Namely, since the image processing apparatus according to the
present embodiment can independently perform processing on each
layer surface, in the processing illustrated in FIG. 8, the image
processing apparatus according to the present embodiment forms
successive X-ray images each time projection data is acquired.
[0107] Therefore, in a helical scanning type CT apparatus or a
non-helical scanning type CT apparatus like that illustrated in
FIG. 7, the image processing apparatus according to the present
embodiment perform the calculations relating to the formation of
the X-ray image, such as a reconstitution calculation, in order
from the portions for which scanning has finished. For example, the
calculations relating to the formation of the X-ray image can be
completed along with as the finishing of the CT scanning.
[0108] Further, since the image processing apparatus according to
the present embodiment forms successive X-ray images each time
projection data is acquired, the amount of memory that is used in
one calculation is substantially reduced.
(Image Processing Apparatus According to the Present
Embodiment)
[0109] Next, an example of the configuration of an image processing
apparatus according to the present embodiment that is capable of
performing the processing performed in the above-described image
processing method according to the present embodiment will be
described.
(I) Example of the Configuration of the Image Processing System
According to the Present Embodiment
[0110] Before describing an example of the configuration of the
image processing apparatus according to the present embodiment, an
example of the image processing system according to the present
embodiment that has the image processing apparatus according to the
present embodiment will be described. FIG. 9 is an explanatory
diagram illustrating an example of an image processing system 1000
according to the present embodiment. The image processing system
1000 has, for example, an image processing apparatus 100, an X-ray
output apparatus 200, and a detection apparatus 300.
[0111] The X-ray output apparatus 200 includes, for example, an
X-ray source (not illustrated), for outputting parallel beam
X-rays. Here, examples of the X-ray source included in the X-ray
output apparatus 200 include an X-ray tube, which is an electron
tube for generating X-rays, a colimeter that forms parallel beam
X-rays from X-rays generated by an X-ray tube, and a planar source
in which a plurality of X-ray tubes are arranged on a flat
face.
[0112] It is noted that the configuration of the X-ray output
apparatus 200 is not limited to that described above. For example,
the X-ray output apparatus 200 is configured from a MPU
(micro-processing unit), various processing circuits and the like.
Further, the X-ray output apparatus 200 may also include a control
unit (not illustrated) for controlling the generation of X-rays by
the X-ray source, a ROM (read-only memory, not illustrated), a RAM
(not illustrated) and the like.
[0113] Here, the ROM (not illustrated) included in the X-ray output
apparatus 200 stores control data, such as programs and calculation
parameters used by the control unit (not illustrated) included in
the detection apparatus 300. The RAM included in the X-ray output
apparatus 200 temporarily stores programs, for example, that are
executed by the control unit (not illustrated) included in the
X-ray output apparatus 200.
[0114] The detection apparatus 300, which includes a detection unit
(not illustrated) that has a detector for detecting X-rays, for
example, detects parallel beam X-rays and generates parallel X-ray
detection data.
[0115] It is noted that the configuration of the detection
apparatus 300 is not limited to that described above. For example,
the detection apparatus 300 is configured from a MPU, various
processing circuits and the like. Further, the detection apparatus
300 may also include a processing unit (not illustrated) for
converting parallel X-ray detection data into projection data, a
ROM (read-only memory, not illustrated), a RAM (not illustrated), a
communication unit and the like.
[0116] Here, the ROM (not illustrated) included in the detection
apparatus 300 stores control data, such as programs and calculation
parameters used by the control unit (not illustrated) included in
the detection apparatus 300. The RAM included in the detection
apparatus 300 temporarily stores programs, for example, that are
executed by the control unit (not illustrated) included in the
detection apparatus 300.
[0117] The communication unit (not illustrated) included in the
detection apparatus 300 is a communication device included in the
detection apparatus 300, which has the role of performing
wireless/wired communication with an external device, such as the
image processing apparatus 100, via a network (or directly). Here,
examples of the communication unit (not illustrated) included in
the detection apparatus 300 include a communication antenna and an
RF (radio frequency) circuit (wireless communication), an IEEE
802.15.1 port and a transmitting/receiving circuit (wireless
communication), an IEEE 802.11b port and a transmitting/receiving
circuit (wireless communication), or a LAN (local area network)
terminal and a transmitting/receiving circuit (wired communication)
and the like. Further examples of the communication unit (not
illustrated) included in the detection apparatus 300 include a
configuration that supports an arbitrary standard capable of
performing communication, such as a USB (universal serial bus)
terminal and a transmitting/receiving circuit, and an arbitrary
configuration capable of communicating with an external device via
a network. Examples of the network according to the embodiment of
the present disclosure include a wired network such as a LAN or a
WAN (wide area network), a wireless network such as a wireless LAN
(wireless local area network), and wireless WAN (wireless wide area
network) via a base station, or the Internet using a communication
protocol such as TCP/IP (transmission control protocol/internet
protocol) and the like.
[0118] The detection apparatus 300 transmits to the image
processing apparatus 100, for example, the generated parallel X-ray
detection data or projection data in which parallel X-ray detection
data has been converted.
[0119] The image processing apparatus 100 forms an X-ray image
based on parallel X-ray detection data by performing the
above-described processing performed in the image processing method
according to the present embodiment, and processing parallel X-ray
detection data or projection data in which parallel X-ray detection
data has been converted.
[0120] Here, the image processing apparatus 100 processes, for
example, parallel X-ray detection data transmitted from the
detection apparatus 300, or projection data transmitted from the
detection apparatus 300 in which parallel X-ray detection data has
been converted. It is noted that the image processing apparatus 100
can process, for example, parallel X-ray detection data stored in a
storage unit (described below) or the like, or projection data
stored in the storage unit (described below) or the like in which
parallel X-ray detection data has been converted. Examples of
parallel X-ray detection data stored in the storage unit (described
below) or the like include parallel X-ray detection data generated
by the detection apparatus 300 and parallel X-ray detection data
generated by an external device other than the detection apparatus
300. Further, examples of projection data stored in the storage
unit (described below) or the like in which parallel X-ray
detection data has been converted include projection data converted
by the detection apparatus 300 and projection data generated by an
external device other than the detection apparatus 300.
[0121] The image processing system 1000 has, for example, the
configuration illustrated in FIG. 9. In the image processing system
1000 illustrated in FIG. 9, the image processing apparatus 100
forms an X-ray image based on parallel X-ray detection data by
performing the above-described processing performed in the image
processing method according to the present embodiment. Therefore,
based on the configuration illustrated in FIG. 9, for example, an
image processing system is realized that can achieve a higher
quality X-ray image while reducing the calculation costs for
forming an X-ray image even further.
[0122] It is noted that the image processing system according to
the present embodiment is not limited to the configuration
illustrated in FIG. 9. For example, in the image processing system
according to the present embodiment, the X-ray output apparatus 200
and the detection apparatus 300 may be an integrated apparatus,
like a CT apparatus that utilizes X-rays or an apparatus having a
tomosynthesis function in which X-rays are utilized. Further, if
the X-ray output apparatus 200 and the detection apparatus 300 are
an integrated apparatus, such an apparatus may include a gantry
that has a rotary motor, for example.
(II) Example of the Configuration of the Image Processing Apparatus
According to the Present Embodiment
[0123] Next, an example of the configuration of the image
processing apparatus according to the present embodiment will be
described using the image processing apparatus 100 configuring the
image processing system 1000 illustrated in FIG. 9 as an
example.
[0124] FIG. 10 is a block diagram illustrating an example of a
configuration of an image processing apparatus 100 according to an
embodiment of the present disclosure. The image processing
apparatus 100 includes, for example, a communication unit 102 and a
control unit 104.
[0125] Further, the image processing apparatus 100 may also
include, for example, a ROM (not illustrated), a RAM (not
illustrated), a storage unit (not illustrated), a user-operable
operation unit (not illustrated), a display unit (not illustrated)
that displays various screens on a display screen and the like. The
image processing apparatus 100 connects these constituent elements
to each other with a bus that serves as a data transmission
path.
[0126] Here, the ROM (not illustrated) stores control data, such as
programs and calculation parameters used by the control unit 104.
The RAM (not illustrated) temporarily stores programs and the like
that are executed by the control unit 104.
[0127] The storage unit (not illustrated) is a storage device
included in the image processing apparatus 100, which stores, for
example, various data such as X-ray detection data, projection data
in which X-ray detection data has been converted, and applications.
Here, examples of the storage unit (not illustrated) include
magnetic recording media such as a hard disk, non-volatile memory
such as flash memory and the like. Further, the storage unit (not
illustrated) may be detachable from the image processing apparatus
100.
[0128] In addition, examples of the operation unit (not
illustrated) include the below-described operation input device.
Examples of the display unit (not illustrated) may include the
below-described display device.
(Hardware Configuration Example of the Image Processing Apparatus
100)
[0129] FIG. 11 is an explanatory diagram illustrating an example of
a hardware configuration of the image processing apparatus 100
according to an embodiment of the present disclosure. The image
processing apparatus 100 includes, for example, a MPU 150, a ROM
152, a RAM 154, a recording medium 156, an input/output interface
158, an operation input device 160, a display device 162, and a
communication interface 164. Further, the image processing
apparatus 100 connects these constituent elements to each other
with a bus 166 that serves as a data transmission path.
[0130] The MPU 150 is configured from, for example, a MPU, various
processing circuits and the like. The MPU 150 functions as the
control unit 104 for controlling the whole image processing
apparatus 100. Further, in the image processing apparatus 100, the
MPU 150 plays the role of, for example, the below-described
processing unit 110.
[0131] The ROM 152 stores control data, such as programs and
calculation parameters used by the MPU 150. The RAM 154 temporarily
stores programs and the like, for example, that are executed by the
MPU 150.
[0132] The recording medium 156 functions as a storage unit, which
stores, for example, various data such as X-ray detection data,
projection data in which X-ray detection data has been converted,
and applications. Here, examples of the recording medium 156
include magnetic recording media such as a hard disk, non-volatile
memory such as flash memory and the like. Further, the recording
medium 156 may be detachable from the image processing apparatus
100.
[0133] The input/output interface 158, for example, connects the
operation input device 160 and the display device 162. The
operation input device 160 functions as an operation unit (not
illustrated), and the display device 162 functions as a display
unit (not illustrated). Here, examples of the input/output
interface 158 includes a USB terminal, a DVI (digital visual
interface) terminal, a HDMI (high-definition multimedia interface)
terminal, various processing circuits and the like. Further, the
operation input device 160 is, for example, included on the image
processing apparatus 100, and is connected with the input/output
interface 158 in the image processing apparatus 100. Examples of
the operation input device 160 include a button, a direction key, a
rotating-type selector such as a jog dial, or a combination of
these. Further, the display device 162 is, for example, included on
the image processing apparatus 100, and is connected with the
input/output interface 158 in the image processing apparatus 100.
Examples of the input/output interface 158 include a liquid crystal
display (LCD), an organic EL display (organic electroluminescence
display, also called an OLED (organic light emitting diode
display)) and the like.
[0134] It is noted that the input/output interface 158 is obviously
also connected to an external device, such as an operation input
device (e.g., a keyboard, a mouse etc.) or a display device, as an
external device of the image processing apparatus 100. Further, the
display device 162 may also be a device that can perform a display
and user operations.
[0135] The communication interface 164 is a communication unit
included in the image processing apparatus 100, which functions as
the communication unit 102 for performing wireless/wired
communication with the detection apparatus 300 or an external
device, such as a server, via a network (or directly). Here,
examples of the communication interface 164 include a communication
antenna and an RF circuit (wireless communication), an IEEE
802.15.1 port and a transmitting/receiving circuit (wireless
communication), an IEEE 802.11b port and a transmitting/receiving
circuit (wireless communication), or a LAN (local area network)
terminal and a transmitting/receiving circuit (wired communication)
and the like.
[0136] The image processing apparatus 100 performs the processing
performed in the image processing method according to the present
embodiment based on the configuration illustrated in FIG. 11, for
example. However, the hardware configuration of the image
processing apparatus 100 according to the present embodiment is not
limited to the configuration illustrated in FIG. 11. For example,
if the image processing apparatus 100 performs the processing as a
standalone configuration, the image processing apparatus 100 may be
configured without the communication device 164. In addition, the
image processing apparatus 100 may also be configured without the
operation input device 160 or the display device 162.
[0137] An example of the configuration of the image processing
apparatus 100 will be described again with reference to FIG. 10.
The communication unit 102 is a communication unit included in the
image processing apparatus 100, which performs wireless/wired
communication with the detection apparatus 300 or an external
device, such as a server, via a network (or directly). Further,
communication by the communication unit 102 is controlled by the
control unit 104, for example. Here, examples of the communication
unit 102 include a communication antenna and an RF (radio
frequency) circuit, a LAN terminal, a transmitting/receiving
circuit and the like. However, the configuration of the
communication unit 102 is not limited to these examples. For
example, the communication unit 102 may have a configuration that
supports an arbitrary standard that is capable of performing
communication, such as a USB terminal and a transmitting/receiving
circuit, or an arbitrary configuration that is capable of
communicating with an external device via a network.
[0138] The control unit 104 is configured from a MPU, for example,
which plays the role of controlling the whole image processing
apparatus 100. Further, the control unit 104 which includes, for
example, the processing unit 110, plays the lead role in the
processing performed in the image processing method according to
the present embodiment.
[0139] The processing unit 110, which plays the lead role in the
processing performed in the image processing method according to
the present embodiment, forms an X-ray image based on X-ray
detection data by processing projection data in which parallel
X-ray detection data (X-ray detection data representing a detection
result of parallel beam X-rays output from an X-ray source) has
been converted by projection. More specifically, the processing
unit 110 forms an X-ray image based on X-ray detection data by
performing the processing according to the above-described first
example, the processing according to the above-described second
example, or the processing according to the above-described third
example.
[0140] Here, for example, if it is possible to directly process the
projection data in which parallel X-ray detection data has been
converted, such as when the communication unit 102 has received
projection data in which parallel X-ray detection data has been
converted, the processing unit 110 process that projection data.
Further, for example, in the case of processing the parallel X-ray
detection data, such as when the communication unit 102 has
received parallel X-ray detection data, the processing unit 110
converts the parallel X-ray detection data and processes the
converted projection data. It is noted that the processing unit 110
can also process parallel X-ray detection data stored in a storage
unit (described below) or the like, or projection data stored in
the storage unit (described below) or the like in which parallel
X-ray detection data has been converted.
[0141] The control unit 104 plays the lead role in the processing
performed in the image processing method according to the present
embodiment due to its inclusion of the processing unit 110, for
example.
[0142] The image processing apparatus 100 performs the processing
performed in the image processing method according to the present
embodiment based on the configuration illustrated in FIG. 10, for
example.
[0143] Therefore, the image processing apparatus 100 can achieve a
higher quality X-ray image while reducing the calculation costs for
forming an X-ray image even further. Further, the image processing
apparatus 100 achieves the effects gained from performing the
processing according to the above-described first example when
performing the processing according to the above-described first
example, achieves the effects gained from performing the processing
according to the above-described second example when performing the
processing according to the above-described second example, and
achieves the effects gained from performing the processing
according to the above-described third example when performing the
processing according to the above-described third example.
[0144] It is noted that the configuration of the image processing
apparatus according to the present embodiment is not limited to the
configuration illustrated in FIG. 10.
(i) First Modified Example
[0145] For example, the image processing apparatus according to the
present embodiment may further include a detection unit (not
illustrated) having a similar function and configuration to the
detection apparatus 300 illustrated in FIG. 9. The detection unit
(not illustrated) detects parallel beam X-rays and generates
parallel X-ray detection data, for example. Further, the detection
unit (not illustrated) may also have a function for, for example,
detecting parallel beam X-rays, generating parallel X-ray detection
data, and converting the generated parallel X-ray detection data
into projection data by projection.
[0146] When the detection unit (not illustrated) detects parallel
beam X-rays and generates parallel X-ray detection data, for
example, the processing unit 110 converts the X-ray detection data
generated by the detection unit (not illustrated) into projection
data by projection, and processes the converted projection data.
Further, in the case of the detection unit (not illustrated)
detecting parallel beam X-rays, generating parallel X-ray detection
data, and converting the generated parallel X-ray detection data
into projection data by projection, the processing unit 110
processes the projection data converted by the detection unit (not
illustrated). It is noted that the processing unit 110 according to
the first modified example of the present embodiment may also
process parallel X-ray detection data stored in a storage unit
(described below), or projection data in which parallel X-ray
detection data stored in a storage unit (described below) has been
converted.
[0147] Similar to the image processing apparatus 100 illustrated in
FIG. 10, even if it further includes a detection unit (not
illustrated), the image processing apparatus according to the first
modified example of the present embodiment can perform the
processing performed in the image processing method according to
the present embodiment. Therefore, the image processing apparatus
according to the first modified example of the present embodiment
can obtain the same effects as the image processing apparatus 100
illustrated in FIG. 10.
[0148] The image processing apparatus according to the present
embodiment may further include, in addition to the configuration of
the image processing apparatus according to the first modified
example of the present embodiment, an X-ray output unit (not
illustrated) having a similar function and configuration to the
X-ray output apparatus 200 illustrated in FIG. 9. The X-ray output
unit (not illustrated) has an X-ray source that outputs parallel
beam X-rays, for example. Further, the generation of the X-rays in
the X-ray output unit (not illustrated) is controlled by the
control unit 104, for example.
[0149] With the image processing apparatus according to the second
modified example of the present embodiment, which in addition to
the configuration illustrated in FIG. 10, further includes an X-ray
output unit (not illustrated) and a detection unit (not
illustrated), the detection unit (not illustrated) can detect
parallel beam X-rays output from the X-ray output unit (not
illustrated), for example, and the processing unit 110 can process
projection data in which parallel X-ray detection data representing
a detection result has been converted by the detection unit (not
illustrated). It is noted that the processing unit 110 according to
the second modified example of the present embodiment can also
process parallel X-ray detection data stored in a storage unit
(described below) or the like, or projection data stored in the
storage unit (described below) or the like in which parallel X-ray
detection data has been converted.
[0150] Therefore, even with a configuration that additionally
includes an X-ray output unit (not illustrated) and a detection
unit (not illustrated), similar to the image processing apparatus
100 illustrated in FIG. 10, the image processing apparatus
according to the second modified example of the present embodiment
can perform the processing performed in the image processing method
according to the present embodiment.
[0151] Therefore, the image processing apparatus according to the
first modified example of the present embodiment can obtain the
same effects as the image processing apparatus 100 illustrated in
FIG. 10.
(iii) Third Modified Example
[0152] When the image processing apparatus according to the present
embodiment performs processing as a standalone configuration, for
example, the image processing apparatus according to the present
embodiment may be configured without the communication unit
102.
[0153] Although an image processing apparatus was described above
as an embodiment of the present disclosure, the present embodiment
is not limited to this example. The present embodiment can also be
used in various devices that are capable of processing an image,
such as a computer like a PC (personal computer) or a server, a CT
apparatus (an apparatus that uses 360.degree. direction projection
data), an apparatus having a tomosynthesis function (an apparatus
that uses projection data of a controlled angle direction, such as
180.degree. direction projection data), a communications device
such as a smartphone and the like. Further, the present embodiment
can also be applied in a processing IC (integrated circuit) that
can be incorporated in such devices.
(Program According to the Present Embodiment)
[0154] By executing on a computer a program that makes a computer
function as the image processing apparatus according to the present
embodiment (e.g., a program capable of executing the processing
performed in the image processing method according to the present
embodiment, such as a program that makes a computer function as the
processing unit 110 illustrated in FIG. 10), a higher quality X-ray
image can be achieved while reducing the calculation costs for
forming an X-ray image even further.
[0155] It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations and
alterations may occur depending on design requirements and other
factors insofar as they are within the scope of the appended claims
or the equivalents thereof.
[0156] For example, although a program (computer program) that
makes a computer function as the image processing apparatus
according to the present embodiment was described above, the
present embodiment can further provide a recording medium in which
this program is stored.
[0157] The above-described configuration illustrates one example of
the present embodiment, and naturally comes under the technical
scope of an embodiment according to the present disclosure.
[0158] Additionally, the present technology may also be configured
as below.
(1) An image processing apparatus including:
[0159] a processing unit configured to processes projection data in
which X-ray detection data representing a detection result of
parallel beam X-rays output from an X-ray source has been converted
by projection, and form an X-ray image based on the X-ray detection
data.
(2) The image processing apparatus according to (1), wherein the
processing unit is configured to divide the projection data and
form the X-ray image per piece of divided projection data. (3) The
image processing apparatus according to (1), wherein the processing
unit is configured to form the X-ray image each time the projection
data is acquired. (4) The image processing apparatus according to
any one of (1) to (3), further including:
[0160] a detection unit configured to detect the parallel beam
X-rays, generate the X-ray detection data, and convert the
generated X-ray detection data into the projection data,
[0161] wherein the processing unit is configured to process the
projection data converted by the detection unit.
(5) The image processing apparatus according to any one of (1) to
(3), further including:
[0162] a detection unit configured to detect the parallel beam
X-rays and generate the X-ray detection data,
[0163] wherein the processing unit is configured to convert the
X-ray detection data generated by the detection unit into the
projection data, and process the converted projection data.
(6) The image processing apparatus according to (4) or (5), further
including:
[0164] an X-ray output unit that includes the X-ray source for
outputting the parallel beam X-rays.
(7) An image processing method including:
[0165] processing projection data in which X-ray detection data
representing a detection result of parallel beam X-rays output from
an X-ray source has been converted by projection, and forming an
X-ray image based on the X-ray detection data.
(8) An Image Processing System Including:
[0166] an X-ray output apparatus that includes an X-ray source for
outputting parallel beam X-rays;
[0167] a detection apparatus configured to detect the parallel beam
X-rays, generate X-ray detection data representing a detection
result of the parallel beam X-rays, and convert the generated X-ray
detection data into projection data by projection; and
[0168] an image processing apparatus that includes a processing
unit configured to process projection data in which the X-ray
detection data has been converted, and form an X-ray image based on
the X-ray detection data.
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