U.S. patent application number 12/371001 was filed with the patent office on 2009-08-27 for system and method for multi-resolution storage of images.
Invention is credited to Andrew Cilia, Robert V. Vanman.
Application Number | 20090213218 12/371001 |
Document ID | / |
Family ID | 40954748 |
Filed Date | 2009-08-27 |
United States Patent
Application |
20090213218 |
Kind Code |
A1 |
Cilia; Andrew ; et
al. |
August 27, 2009 |
SYSTEM AND METHOD FOR MULTI-RESOLUTION STORAGE OF IMAGES
Abstract
A data-storage method includes capturing video data, identifying
an object of which a high-resolution image is desired, the object
being represented by a subset of the captured video data,
compressing, to a first resolution, the subset of the captured
video data, and compressing, to a second resolution, data of the
captured video data other than the subset of the captured video
data. According to the method, the first resolution is greater than
the second resolution. The method further includes storing the
compressed video data.
Inventors: |
Cilia; Andrew; (McKinney,
TX) ; Vanman; Robert V.; (McKinney, TX) |
Correspondence
Address: |
WINSTEAD PC
P.O. BOX 50784
DALLAS
TX
75201
US
|
Family ID: |
40954748 |
Appl. No.: |
12/371001 |
Filed: |
February 13, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61029101 |
Feb 15, 2008 |
|
|
|
61029092 |
Feb 15, 2008 |
|
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Current U.S.
Class: |
348/143 ;
348/E7.085 |
Current CPC
Class: |
H04N 19/17 20141101;
G06K 2209/15 20130101; H04N 19/136 20141101 |
Class at
Publication: |
348/143 ;
348/E07.085 |
International
Class: |
H04N 7/26 20060101
H04N007/26; H04N 7/18 20060101 H04N007/18 |
Claims
1. A data-storage method comprising: capturing video data;
identifying an object of which a high-resolution image is desired,
the object being represented by a subset of the captured video
data; compressing, to a first resolution, the subset of the
captured video data; compressing, to a second resolution, data of
the captured video data other than the subset of the captured video
data; wherein the first resolution is greater than the second
resolution; and storing the compressed video data.
2. The data-storage method of claim 1, wherein the identifying step
comprises: obtaining location information corresponding to the
object; and identifying the subset of the captured video data using
the location information.
3. The data-storage method of claim 1, wherein the identifying step
comprises operation of a license-plate-location algorithm.
4. The data-storage method of claim 1, wherein the identifying step
is performed responsive to user input.
5. The data-storage method of claim 1, wherein the location
information comprises at least one set of coordinates.
6. The data-storage method of claim 5, wherein the at least one set
of coordinates corresponds to corners of at least one vehicular
license plate.
7. The data-storage method of claim 1, wherein the object comprises
a face of an individual.
8. The data-storage method of claim 1, wherein the identifying step
is performed via a fixed area of a display.
9. The data-storage method of claim 1, wherein the subset of the
captured video data excludes chroma information.
10. An article of manufacture for data storage, the article of
manufacture comprising: at least one computer readable medium;
processor instructions contained on at least one computer readable
medium, the processor instructions configured to be readable from
the at least one computer readable medium by at least one processor
and thereby cause the at least one processor to operate as to
perform the following steps: capturing video data; identifying an
object of which a high-resolution image is desired, the object
being represented by a subset of the captured video data;
compressing, to a first resolution, the subset of the captured
video data; compressing, to a second resolution, data of the
captured video data other than the subset of the captured video
data; wherein the first resolution is greater than the second
resolution; and storing the compressed video data.
11. The article of manufacture of claim 10, wherein the identifying
step comprises: obtaining location information corresponding to the
object; and identifying the subset of the captured video data using
the location information.
12. The article of manufacture of claim 10, wherein the identifying
step comprises operation of a license-plate-location algorithm.
13. The article of manufacture of claim 10, wherein the identifying
step is performed responsive to user input.
14. The article of manufacture of claim 10, wherein the location
information comprises at least one set of coordinates.
15. The article of manufacture of claim 14, wherein the at least
one set of coordinates corresponds to corners of at least one
vehicular license plate.
16. The article of manufacture of claim 10, wherein the object
comprises a face of an individual.
17. The article of manufacture of claim 10, wherein the identifying
step is performed via a fixed area of a display.
18. The article of manufacture of claim 10, wherein the subset of
the captured video data excludes chroma information.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority from, and
incorporates by reference for any purpose the entire disclosure of,
U.S. Provisional Patent Application No. 61/029,101, filed Feb. 15,
2008. In addition, this patent application claims priority from and
incorporates by reference U.S. Provisional Patent Application No.
61/029,092, also filed Feb. 15, 2008. This patent application also
incorporates by reference U.S. Patent Application Publication No.
2006/0158968, filed on Oct. 12, 2005, and a patent application
filed on the same date as this patent application and bearing
Docket No. 47565-P007US.
BACKGROUND
[0002] 1. Technical Field
[0003] This patent application relates generally to video
surveillance, and in particular, to systems and methods for
multi-resolution storage of images.
[0004] 2. Background
[0005] Many law-enforcement vehicles include a video camera to
capture video of activities transpiring both outside and inside the
vehicle. One use of the video captured by these video cameras is as
evidence in a criminal trial. In order for these videos to be used
as evidence, the images must be clearly identifiable by, for
example, a jury or an expert witness. Often the law-enforcement
vehicles and their video recording devices remain in use for
extended periods of time, for example, when an officer stays out
all night on patrol. It is therefore often necessary to compress
the video being recorded in order to be able to store large volumes
of data.
SUMMARY OF THE INVENTION
[0006] A data-storage method includes capturing video data,
identifying an object of which a high-resolution image is desired,
the object being represented by a subset of the captured video
data, compressing, to a first resolution, the subset of the
captured video data, and compressing, to a second resolution, data
of the captured video data other than the subset of the captured
video data. According to the method, the first resolution is
greater than the second resolution. The method further includes
storing the compressed video data.
[0007] An article of manufacture for data storage includes at least
one computer readable medium and processor instructions contained
on the at least one computer readable medium. The processor
instructions are configured to be readable from the at least one
computer readable medium by at least one processor and thereby
cause the at least one processor to operate as to capture video
data and identify an object of which a high-resolution image is
desired, the object being represented by a subset of the captured
video data. The processor instructions are further configured to
cause the at least one processor to operate as to compress, to a
first resolution, the subset of the captured video data, and
compress, to a second resolution, data of the captured video data
other than the subset of the captured video data. According to the
article of manufacture, the first resolution is greater than the
second resolution. The processor instructions are further
configured to cause the at least one processor to operate as to
store the compressed video data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] A more complete understanding of various embodiments of the
present invention may be obtained by reference to the following
Detailed Description when taken in conjunction with the
accompanying Drawings, wherein:
[0009] FIG. 1 is a schematic diagram of a system for capturing and
storing video data;
[0010] FIG. 2 is a flow chart illustrating a process for
compressing and storing video data;
[0011] FIG. 3 is an illustrative view of a video-data image;
and
[0012] FIG. 4 illustrates a system for capturing and storing video
data.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0013] Various embodiments of the present invention will now be
described more fully with reference to the accompanying drawings.
The invention may, however, be embodied in many different forms and
should not be construed as limited to the embodiments set forth
herein; rather, the embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the invention to those skilled in the art.
[0014] In a typical embodiment, pixels of a video stream coming
from a video camera in a vehicle such as, for example, a
law-enforcement vehicle may contain both chroma (color information)
and luma (brightness or black and white information). Most of the
resolution may be contained in the black and white information of
the video stream, even though the images may be color images.
Between the luma and chroma information, the luma may contain much
of the information relative to how much detail in the video stream
is visible.
[0015] In order to store over long periods of time a typically
large amount of video data captured by the video camera,
data-compression algorithms are often used to compress the video
data. In a typical embodiment, the video data may be, for example,
still images or motion video. There are various data-compression
algorithms currently in use for compressing video data. The
data-compression algorithms may include, for example, lossless
algorithms and lossy algorithms. Lossless algorithms are a class of
data-compression algorithms that allow a replica of original data
to be reconstructed from compressed data. In contrast, lossy
algorithms are a class of data-compression algorithms that allow an
approximation of the original data to be reconstructed in exchange
for a better data-compression rate. In a lossy algorithm, some
visual quality is lost in the data-compression process, which lost
visual quality cannot be restored. Data-compression algorithms
typically utilize a combination of techniques for compressing, for
example, video data. The combination of techniques for compressing
the video data may include, for example, downsampling or
subsampling, block splitting, pixelating, and/or lessening
resolution.
[0016] A few examples of data-compression algorithms include the
MPEG family of algorithms such as, for example, MPEG 2 and MPEG 4.
Almost all data-compression algorithms lessen the clarity and
sharpness of the compressed video data, making, for example, facial
features, letters, and numbers more difficult to identify. Because
clarity is often critical in police work such as, for example, in
identifying a particular vehicle or suspect to a jury, it is
important that the images remain sufficiently clear even after the
video data has been compressed. For example, when video of a
traffic stop is recorded, it is important that the clarity, for
example, of a license plate of the vehicle remain uncompromised so
that letters and numbers of the license plate are identifiable.
[0017] In a typical embodiment, some cameras may, for example,
capture video data at approximately 480 horizontal lines while the
video data may be recorded at, for example, 86 horizontal lines.
The resolution of the video data being recorded may be, for
example, one fourth the resolution of what the camera actually
captured. By accessing the video data while the video data is still
at a maximal (i.e., uncompressed) resolution, effects of
data-compression algorithms and recording on the readability of,
for example, license plates and other objects can be minimized.
[0018] FIG. 1 is a schematic diagram of a system 100 for capturing
and storing video data. The system 100 includes an image-capture
device 102 for capturing raw video data. The image-capture device
102 may, for example, be located at various locations within or on
a police vehicle. In a typical embodiment, the image-capture device
102 may, for example, be located on a front console of the
law-enforcement vehicle in order to capture areas of interest
outside of the law-enforcement vehicle. In a typical embodiment,
the image-capture device 102 is a digital video camera. The system
100 further includes a buffer 104 interoperably connected to the
image-capture device 102. The captured raw video data is
transmitted by the image-capture device 102 to the buffer 104. The
buffer 104 is used for temporary storage of the raw video data.
[0019] The system 100 also includes a zoom-area locator 106. The
zoom-area locator 106 is adapted to find coordinates corresponding
to a subset of the raw video data that pertains to one or more
areas of interest. In a typical embodiment, an area of interest may
be, for example, a vehicle license plate, facial features of an
individual, or any other items that require retention at higher
resolution levels. The coordinates are transmitted from the
zoom-area locator 106 to a compressor 110. In a typical embodiment,
the one or more areas of interest may be, for example, one or more
license plates located by a license-plate location algorithm.
[0020] In a typical embodiment, the compressor 110 is adapted to
compresses video data from the one or more areas of interest at a
first resolution level and areas other than the one or more areas
of interest at a second resolution level. The first resolution
level is often greater than the second resolution level. For
example, at the first resolution level, the video data is often
compressed substantially less than at the second resolution level.
In some embodiments, the first resolution level may be obtained by
not compressing the video data at all. The video data is stored on
a storage medium 112. In a typical embodiment, the storage medium
112 uses a hard drive, DVD, or other recording medium.
[0021] In various embodiments, area(s) of interest compressed at
the first resolution level may be fixed in particular position(s)
within a field of view of the image-capture device 102. In some
embodiments, a law-enforcement officer can, for example, point the
image-capture device 102 in a particular direction to capture the
area(s) of interest. For example, the law-enforcement officer may
pull up behind a vehicle and steer the law-enforcement vehicle so
that the fixed area captures the license plate of the vehicle.
Another way of changing the field of view of the image-capture
device 102 may include, for example, rotating the image-capture
device 102 so that the fixed area covers an area of interest. In
some embodiments, the area to be compressed at the first resolution
level may be moved digitally within the field of view via a user
interface. Each of the buffer 104, the compressor 110, and the
storage medium 112 may be implemented using one or both of hardware
and software.
[0022] In a typical embodiment, the area(s) of interest may be
highlighted. For example, a thin colored line may encompass a
license plate within an area of interest. In some embodiments,
multiple license plates may be identified in one field of view. The
license plates may, for example, be individually focused on by
rotating the area being focused on among the various license
plates. As each license plate is, in turn, focused on, an
indicator, for example, a thin red line, may, for example,
highlight the license plate being focused on. In some embodiments,
a plurality of different indicators may be used. In some
embodiments, a plurality of different license plates may be focused
on at the same time. In various embodiments, facial features of an
individual or other information may be encompassed by an area of
interest.
[0023] In some embodiments, a fixed region, for example, a strip
across a width of displayed video, may include the area of interest
that has been compressed at the first resolution level. Oftentimes,
a hood of the law-enforcement vehicle is in the field of view of
the image-capture device 102. Since video of the hood does not
typically need to be recorded, it may be desirable to insert the
video being compressed at the first resolution level at a bottom of
the field of view. Similarly, oftentimes the sky is recorded; in
that case, it may be desirable to insert the strip of video across
the top of the field of view where the sky is usually shown. In
other embodiments, a vertical strip having more clarity may be
desirable. In various embodiments, a user has the option of
selecting the size and shape of the area of interest and where the
images should be inserted.
[0024] In some embodiments, the video data saved on the storage
device 112 may use approximately the same amount of storage space
as other compressed video data. Because areas of greater resolution
such as, for example, areas at the first resolution level,
typically consume more data-storage space, other areas of the video
data may be compressed to an even lesser resolution. For example,
the hood of the law-enforcement vehicle shown, for example, along
the bottom of the field of view or the sky shown, for example,
along the top of the field of view may be compressed to a lesser
resolution. The potentially deleterious effects of the lesser
resolution is typically offset by areas of interest having been
stored at greater resolution levels. In some embodiments, a
plurality of areas of interest are compressed to a plurality of
different levels of resolution. Similarly, in some embodiments,
areas outside the areas of interest may be compressed to a
plurality of different levels of resolution. Those having skill in
the art will appreciate that various embodiments may use the
above-described processes in conjunction with optical and/or
digital zoom functions.
[0025] FIG. 2 is a flow chart illustrating a process 200 for
compressing and storing video data. The process 200 begins at step
202. At step 202, an image-capture device such as, for example, a
camera, captures raw video data from a field of view of the
image-capture device. In a typical embodiment, the image-capture
device may be mounted in a law-enforcement vehicle and adapted to
capture the video data while the law-enforcement vehicle is moving
and also when the law-enforcement vehicle is stopped such as, for
example, during a traffic stop. From step 202, the process 200
proceeds to step 204. At step 204, the captured raw video data is
sent to a buffer. At step 206, at least one area of interest in the
captured and buffered video data is located. In some embodiments,
the captured video data is read and an automatic license-plate
locator algorithm is run to identify, for example, whether one or
more license plates are present. In some embodiments, only luma
information and not chroma information may be used. In other words,
chroma information may be discarded and data representing luma
information retained for later use, including compression. The luma
information may have more resolution than the chroma information
and the chroma (color) information may not be as critical for
purposes of clarity, such as readability of numbers on a license
plate. In various embodiments, the license-plate location algorithm
runs on raw data coming from the image-capture device; however, it
is also contemplated that the license-plate location algorithm can
run on compressed data as well.
[0026] After the one or more areas of interest (e.g., license
plates or faces) have been located at step 206, at step 208,
location information relative to each of the located areas of
interest is sent to a compressor. For example, the location
information sent may be one or more sets of coordinates, such as,
for example, coordinates corresponding to the four corners of a
license plate. Information related to, for example, size of the one
or more license plates may also be sent. At step 210, the location
information is used during compression by a data-compression
algorithm of pixels from the one or more areas of interest, for
example, the areas of license plates. The data-compression
algorithm compresses the area of interest less than areas other
than the one or more areas of interest. In this way, the one or
more areas of interest may be subsequently saved at a greater
resolution level, while the other areas are saved at a lesser
resolution level. At step 212, the compressed data is stored on a
recording medium such as, for example, a DVD, a VHS tape, or other
appropriate recording medium. At step 214, the process 200
ends.
[0027] FIG. 3 is an illustrative view of a video-data image 300.
The video-data image 300 includes an area of interest 302. In the
embodiment shown in FIG. 3, the area of interest 302 is located
over a license plate. The area of interest 302 has been compressed
less than the rest of the image, leaving the area of interest 302,
for example, the license plate, clearer, while the remaining image
is not as clear as the license-plate portion covered by the area of
interest 302. In a typical embodiment, an automatic license-plate
locator algorithm or a zoom area may be used to locate the area of
interest 302 in the video-data image 300. In some embodiments, a
user may move the area of interest 302 position the area of
interest 302 over any user-selected area. In some embodiments, the
area of interest 302 may be moved via, for example, a user
interface which may be, for example, a keypad, a touch screen, a
joystick, or other controller.
[0028] FIG. 4 illustrates a system 400 on which capturing and
storing video data may be implemented. The system 400 includes a
bus 402 for communicating information. The system 400 also includes
a processor 404 coupled to the bus 402 and a main memory 406 such
as, for example, a random access memory (RAM) or other dynamic
storage device, coupled to the bus 402.
[0029] The system 400 also includes a read only memory (ROM) 408
connected to the bus 402 for storing, for example, static
information and instructions from the processor 402. The system 400
also includes an image-capture device 410. In a typical embodiment,
the image-capture device 410 is a digital video camera. In a
typical embodiment, various components of the system 400 are used
to compress video data from one or more areas of interest at a
first resolution level and areas other than the one or more areas
of interest at a second resolution level, perform zoom-area
location (e.g., finding coordinates corresponding to a subset of
video data that pertains to one or more areas of interest), and
buffer raw video data as described above.
[0030] Although various embodiments of the method and system of the
present invention have been illustrated in the accompanying
Drawings and described in the foregoing Detailed Description, it
will be understood that the invention is not limited to the
embodiments disclosed, but is capable of numerous rearrangements,
modifications and substitutions without departing from the spirit
of the invention as set forth herein.
* * * * *