U.S. patent application number 09/682135 was filed with the patent office on 2002-02-28 for multiple position guiding lens image scanning method.
Invention is credited to Lin, Chun-Liang, Tseng, Jen-Shou.
Application Number | 20020024710 09/682135 |
Document ID | / |
Family ID | 21660923 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020024710 |
Kind Code |
A1 |
Tseng, Jen-Shou ; et
al. |
February 28, 2002 |
MULTIPLE POSITION GUIDING LENS IMAGE SCANNING METHOD
Abstract
A scanner has a light and a scanning module for scanning light
from a document and generating an image signal of the document. The
scanning module has a plurality of light sensors, and a guiding
lens for delivering light from the document to the light sensors.
The guiding lens moves along a direction perpendicular to its own
normal and may be set on at least a first position and a second
position. The guiding lens is first set on the first position, and
a reference picture is scanned to obtain a first reference image
signal. The guiding lens is then set on the second position, and
the reference picture is again scanned to obtain a second reference
image signal. The guiding lens is then set to the first position or
the second position, according to relative qualities of the first
reference image signal and the second reference image signal.
Inventors: |
Tseng, Jen-Shou; (Miao-Li
Hsien, TW) ; Lin, Chun-Liang; (Hsin-Chu City,
TW) |
Correspondence
Address: |
WINSTON HSU
SF. 389, FU-HO ROAD
YUNGHO CITY, TAIPEI
TW
|
Family ID: |
21660923 |
Appl. No.: |
09/682135 |
Filed: |
July 26, 2001 |
Current U.S.
Class: |
359/210.1 ;
359/474; 359/489.15 |
Current CPC
Class: |
G02B 26/10 20130101;
Y10S 359/90 20130101 |
Class at
Publication: |
359/210 ;
359/474; 359/497 |
International
Class: |
G02B 026/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 28, 2000 |
TW |
089117355 |
Claims
What is claimed is:
1. A method of image scanning used in a scanner, the scanner having
a light source for illuminating a document to be scanned, and a
scanning module for scanning light from the document and generating
an image signal of the document, the scanning module having a
plurality of light sensors for sensing the light from the document,
and at least a guiding lens for delivering light from the document
to the light sensors, the guiding lens moving along a direction
perpendicular to a normal of the guiding lens and capable of being
set on at least a first position and a second position, the method
comprising: setting the guiding lens on the first position, and
using the light source and the scanning module to scan a reference
picture to obtain a first reference image signal; setting the
guiding lens on the second position, and using the light source and
the scanning module to scan the reference picture to obtain a
second reference image signal; setting the guiding lens to the
first position or the second position according to the first
reference image signal and the second reference image signal; and
scanning the document; wherein if the first reference image signal
has fewer flawed areas than the second reference image signal, the
guiding lens is moved to the first position to scan the document,
and if the second reference image signal has fewer flawed areas
than the first reference image signal, the guiding lens is moved to
the second position to scan the document.
2. The method of claim 1 wherein the light sensor and the scanning
module move simultaneously.
3. The method of claim 1 wherein the light source is used to scan
the document by way of reflection.
4. The method of claim 1 wherein the light source is used to scan
the document by the way of transmission.
5. The method of claim 1 wherein the scanner further comprises a
controlling circuit electrically connected to the scanning module
for controlling operations of the scanning module and the guiding
lens.
6. The method of claim 1 wherein the scanner further comprises a
signal processing circuit electrically connected to the sensors for
analyzing flawed areas in the first reference image signals and the
second reference image signals.
7. The method of claim 1 wherein the light sensors are linearly
arranged.
8. The method of claim 1 wherein the scanning module comprises a
plurality of guiding lenses for directing light from the light
source to the light sensors, and each guiding lens moves along a
direction perpendicular to a normal of the corresponding guiding
lens and is capable of being set on a plurality of positions, the
plurality of positions of the plurality of guiding lenses producing
a plurality of different combinations of positions of the guiding
lenses, and the method involves scanning the reference picture to
obtain a plurality of image signals for the different combinations
of positions of the guiding lenses and sets the plurality of
guiding lenses on one of the plurality of position combinations to
perform scanning of the document according to flawed areas in the
plurality of image signals.
9. A method of image scanning used in a scanner, the scanner having
a light source for illuminating a document to be scanned, and a
scanning module for receiving light from the document from the
light source and generating an image signal of the document, the
scanning module having a plurality of light sensors for sensing
light from the document, and at least a guiding lens for delivering
light from the document to the sensors, the guiding lenses moving
along directions perpendicular to a normal of each guiding lens and
each capable of being set on at least a first position and a second
position, the method comprising: setting each guiding light lens on
the corresponding first position, and using the light source and
the scanning module to scan a reference picture to obtain a first
reference image signal; setting each guiding light lens on the
corresponding second position, and using the light source and the
scanning module to scan the reference picture to obtain a second
reference image signal; scanning the document; and performing an
image processing step on image signals obtained from the document
to generate an output image according to the first and the second
reference image signals.
10. The method of claim 9 wherein the scanner further comprises a
controlling circuit electrically connected to the scanning module
for controlling operations of the scanning module and the guiding
light lenses, and a signal processing circuit electrically
connected to the sensors for analyzing flawed areas in the first
and the second reference image signals and for performing the image
processing step.
11. The method of claim 10 wherein the controlling circuit controls
the scanning module to scan the document twice to obtain a first
document image signal and a second document image signal, and the
signal processing circuit performs the image processing step on the
first document image signal according to flawed areas in the first
and the second reference image signals and data from the second
document image signal.
12. The method of claim 11 wherein when performing the image
processing step on the first document image signal, the image
processing circuit replaces flawed areas of the first document
image signal with corresponding image data from the second document
image signal.
13. The method of claim 10 wherein the controlling circuit controls
the scanning module to scan the document once to obtain a third
document image signal, and the signal processing circuit generates
a set of corrective arguments to perform the image processing step
on the third document image signal according to flawed areas in the
first reference image signal and the second reference image
signal.
14. The method of claim 9 wherein the light sensor and the scanning
module move simultaneously.
15. The method of claim 9 wherein the light source is used to scan
the document by the way of reflection.
16. The method of claim 9 wherein the light source is used to scan
the document by the way of transmission.
17. The method of claim 9 wherein the light sensors are linearly
arranged.
18. The method of claim 9 wherein the scanning module comprises a
plurality of guiding lenses for directing light from the light
source to the sensors, each guiding lens moving along a direction
perpendicular to a normal of the guiding lens and capable of being
set on a plurality of positions, the plurality of positions of the
plurality of guiding lenses producing a plurality of different
combinations of positions of the guiding lenses, and the method
involves scanning the reference picture to obtain a plurality of
image signals at different combinations of positions of guiding
lenses and performing the image processing step on the image
signals from the document to produce the output image according to
data in flawed areas in the plurality of image signals.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of image scanning
used in a scanner, and more particularly, to an image scanning
method that improves scan quality.
[0003] 2. Description of the Prior Art
[0004] Please refer to FIG. 1 . FIG. 1 is a diagram of a prior art
scanner 10. The scanner 10 comprises a light source 12 for
illuminating a document 14 to be scanned, a transparent panel 16
for supporting the document 14, and a scanning module 18 for
scanning light from the document 14. When performing a scan, the
light source 1 2 and the scanning module 18 move simultaneously to
scan the document 14.
[0005] As shown in FIG. 1, the scanning module 18 has a plurality
of light sensors 20 for converting light from the light source 12
to digital image signals. Light is directed to the plurality of
sensors 20 by three guiding lenses 22A, 22B, 22C and a lens 24.
[0006] A common problem is scratches or dust on one, or more, of
the guiding lenses 22A, 22B, 22C, which leads to poor scan quality,
examples including, but not limited to, shadows or stripes on the
output image.
SUMMARY OF INVENTION
[0007] It is therefore a primary objective of the present invention
to provide a method of image scanning that increases the
probability of a quality scan.
[0008] In a preferred embodiment, the present invention provides a
method of image scanning used in a scanner. The scanner comprises a
light source for illuminating a document to be scanned, and a
scanning module for scanning light from the document and generating
an image signal of the document. The scanning module comprises a
plurality of light sensors for sensing the light from the document,
and a guiding lens for delivering light from the document to the
light sensors. The guiding lens moves in a direction perpendicular
to the normal of the guiding lens, and it may be set on at least a
first and a second position. The method starts by using the light
source and the scanning module to obtain a first reference image
signal by scanning a reference picture at the first position. At
the second position, the light source and the scanning module are
used to obtain a second reference image signal by scanning a
reference picture. According to the first reference image signal
and the second reference image signal, the guiding lens is set to
either the first position or the second position. Then, the
document is scanned.
[0009] If the first reference image signal has fewer flawed areas
than the second reference image signal, the guiding lens is moved
to the first position to scan the document, and if the second
reference image signal has fewer flawed areas than the first
reference image signal, the guiding lens is moved to the second
position to scan the document.
[0010] It is an advantage of the present invention that the
probability of a quality scan is increased.
[0011] These and other objectives and advantages of the present
invention will no doubt become obvious to those of ordinary skill
in the art after having read the following detailed description of
the preferred embodiment that is illustrated in the various figures
and drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a diagram of a prior art scanner.
[0013] FIG. 2 is a diagram of the present invention scanner.
[0014] FIG. 3 is a diagram of a light path of the scanner shown in
FIG.2.
[0015] FIG. 4 is a flow chart of scanning procedures of a first
preferred embodiment scanner shown in FIG. 2.
[0016] FIG. 5 is a diagram of a first reference image signal
obtained by the scanning procedures shown in FIG. 4.
[0017] FIG. 6 is a diagram of a second reference image signal
obtained by the scanning procedures shown in FIG. 4.
[0018] FIG. 7 is a flow chart of scanning procedures of a second
preferred embodiment scanner shown in FIG. 2.
[0019] FIG. 8 is a diagram of a first reference image signal
obtained by the scanning procedures shown in FIG. 7.
[0020] FIG. 9 is a diagram of a second reference image signal
obtained by the scanning procedures shown in FIG. 7.
[0021] FIG. 10 is a flow chart of scanning procedures of a third
preferred embodiment scanner shown in FIG. 2.
DETAILED DESCRIPTION
[0022] Please refer to FIG. 2 and FIG. 3. FIG. 2 is a perspective
diagram of the present invention scanner 30. FIG. 3 is a diagram of
a light path of the scanner 30 shown in FIG. 2. The scanner 30 has
a light source 32, beneath which is a transparent panel 36, where a
document 34 rests, beneath which is a scanning module 38. When
performing a scan, the light source 32 moves simultaneously with
the scanning module 38 to scan the document 34.
[0023] As shown in FIG. 2, the scanning module 38 has a plurality
of light sensors 40, arranged linearly, a lens 44 for focusing the
light onto the light sensors 40, and three guiding lenses 42A, 42B,
42C for directing the light from the light source 32 to the
plurality of light sensors 40. The guiding lens 42A can move along
a direction perpendicular to a normal (as shown, Z) of the guiding
lens 42A. From FIG. 2, the guiding lens 42A can move on the X-Y
plane. Thus, the guiding lens 42A can be set on at least a first
position 46 and a second position 48. When the guiding lens 42A is
at the first position 46, the light from the document 34 is
reflected by a first area on the guiding lens 42A. When the guiding
lens 42A is at the second position 48, the light from the document
34 is reflected by another area on the guiding lens 42A. The range
of the two areas is not necessarily the same.
[0024] As shown in FIG. 2, the scanner 30 has a reference image 50.
The reference image 50 is not only capable of acting as an image
used for calibration in a prior art scanner but is also capable of
acting as a known image. Before scanning the document 34, the
scanner 30 scans the reference image 50 at different positions,
obtaining different reference image signals. As shown in FIG. 3, a
signal processing circuit 54 electrically connected to the
plurality of sensors 40 analyzes the incoming image signals.
[0025] Please refer to FIG. 4 to FIG. 6. FIG. 4 is a flow chart of
scanning procedures of a first preferred embodiment of the method
for the scanner 30 shown in FIG. 2. FIG. 5 is a diagram of a first
reference image signal 56 obtained by following the flow chart
shown in FIG. 4. FIG. 6 is a diagram of a second reference image
signal 58 obtained by following the flow chart shown in FIG. 4. The
first preferred embodiment of the present invention scanning method
is: Step 100: Start the scan process.
[0026] Step 102: Position the guiding lens 42A at the first
position 46 and use the light source 32 and the scanning module 38
to scan the reference image 50 to obtain the first reference image
signal 56.
[0027] Step 104: Position the guiding lens 42A at the second
position 48 and use the light source 32 and the scanning module 38
to scan the reference image 50 to obtain the second reference image
signal 58.
[0028] Step 106: Position the guiding lens 42A at the first
position 46 or the second position 48 according to the number of
flawed areas in the first and the second reference image signals
56, 58.
[0029] Step 108: Scan the document 34 to be scanned, and output the
final image signal.
[0030] As mentioned above, the controlling circuit 52 positions the
guiding lens 42A at the first position 46 and the second position
48. It scans the reference image 50 twice, obtaining the first and
the second reference image signals 56, 58, respectively. Next, the
signal processing circuit 54 analyzes the flawed areas in the first
and the second reference image signals. If the flawed areas in the
first reference image signal 56 are fewer than the flawed areas in
the second reference image signal 58, the guiding lens 42A is
positioned on the first position 46. If the flawed areas in the
second reference image signal 58 are fewer than the flawed areas in
the first reference image signal 56, the guiding lens 42A is
positioned on the second position 48. The document 34 is then
scanned.
[0031] For example, as shown in FIG. 5 and FIG. 6, the first
reference image signal 56 has a flawed area 56A, and the second
reference image signal 58 has flawed areas 58A and 58B. Reference
image signal 56 has fewer flawed areas than reference image signal
58 does. So, the controlling circuit 50 positions the guiding lens
42A on the first position 46. Then, the document 34 is scanned. In
this manner, scan quality is improved.
[0032] The above guiding lens 42A is not limited to two positions,
and the guiding lens capable of moving is also not limited to the
guiding lens 42A. Designers can design the guiding lenses 42A, 42B,
or 42C to set on more than two positions, depending on design
preference. Additionally, the present invention is not limited to
only one guiding lens 42A, 42B, or 42C that is capable of moving.
If more than one guiding lens is capable of moving along a
direction perpendicular to its own normal, and setting on a
plurality of positions, this also conforms to the present
invention. For the case of multiple movable guiding lenses,many
positioning combinations are possible. Comparison can then take
place on a plurality of reference images, the best image being
chosen for the final scan. In this way, better scanning quality is
obtained.
[0033] Please refer to FIG. 7 to FIG. 9. FIG. 7 is a flow chart of
scanning procedures of a second preferred embodiment of the method
for the scanner 30 shown in FIG. 2. FIG. 8 is a diagram of a first
reference image signal 66 obtained by following the flow chart
shown in FIG. 7. FIG. 9 is a diagram of a second reference image
signal 68 obtained by following the flow chart shown in FIG. 7. The
second preferred embodiment of the present invention scanning
method is: Step 200: Start the scan process.
[0034] Step 202: Position the guiding lens 42A at the first
position 46, and use the light source 32 and the scanning module 38
to scan the reference image 50 to obtain the first reference image
signal 66.
[0035] Step 204: Position the guiding lens 42A at the second
position 48, and use the light source 32 and the scanning module 38
to scan the reference image 50 to obtain the second reference image
signal 68.
[0036] Step 206: Scan the document 34 twice to obtain a first
document image signal and a second document image signal.
[0037] Step 208: From the first and the second reference image
signal 66 and 68, perform image processing on the image signal
obtained by scanning the document 34, using replacement to generate
an output image.
[0038] The controlling circuit 52 positions the guiding lens 42A at
the first position 46 and the second position 48. The reference
image 50 is scanned twice, obtaining the first and the second
reference image signals 66, 68. Next, the first and the second
document image signals are scanned. The signal processing circuit
54 analyzes the flawed areas in the first and the second reference
image signals 66, 68. The signal processing circuit 54 then
performs image processing on the first document image signal
according to the flawed areas in the first and the second reference
image signals 66, 68. When performing image processing, the signal
processing circuit 54 replaces the image data of the flawed areas
in the first document image signal with corresponding image data
from the second document image signal.
[0039] For example, as shown in FIG. 8 and FIG. 9, the first
reference image signal 66 has a flawed area 66A, at a position P1,
and the second reference image signal 68a has a flawed area 68A, at
a position P2. The signal processing circuit 54 replaces the image
data at P1 in the first document image signal with the image data
at P1 in the second document image signal. This improves scan
quality.
[0040] Please refer to FIG. 10. FIG. 10 is a flow chart of the
scanning procedures of a third preferred embodiment of the method
for the scanner 30 shown in FIG. 2. The third preferred embodiment
of the present invention scanning method is: Step 300: Start the
scan process.
[0041] Step 302: Position the guiding lens 42A at the first
position 46, and use the light source 32 and the scanning module 38
to scan the reference image 50 to obtain the first reference image
signal 66.
[0042] Step 304: Position the guiding lens 42A at the second
position 48, and use the light source 32 and the scanning module 38
to scan the reference image 50 to obtain the second reference image
signal 68.
[0043] Step 306: Scan the document 34 once to obtain a document
image signal.
[0044] Step 308: Perform image processing on the image signal
obtained from the scanned document 34 that uses correction to
generate an output image according to the first and the second
reference image signal 66, 68.
[0045] In this embodiment, after obtaining the reference image
signals 66, 68, the controlling circuit 52 only scans the document
34 once to obtain the document image signal. The signal processing
circuit 54 creates a set of corrective arguments to perform the
image processing step in the third document image according to the
data of the flawed areas in the first and second reference image
signals 66, 68. There are many methods of prior art parameter image
processing, such as averages, trend forecasting, etc. Actually,
having just obtained the first and the second reference image
signals 66, 68 according to the methods of the present invention,
the third document image is capable of using the method of the
prior art image processing to improve scan quality.
[0046] Of course, the second and the third preferred embodiment of
the present invention can also work for a plurality of movable
guiding lenses. Each guiding lens is not limited to two positions.
Furthermore, the preferred embodiment above is described for the
case of a transmitted scanner, i.e. the light source 32 is above
the transparent panel 36, and light transmitted through the
document 34 is utilized to scan the document 34. In fact, the
scanning method of the present invention can be used in a
reflective scanner, i.e. the light source 32 is under the
transparent panel 36, and light reflected from the document 34 is
utilized to scan the document 34. In either case, the objective of
the present invention is still achieved.
[0047] In addition, the first and second steps 102, 104, 202, 204,
302, 304 of the present invention for scanning the reference image
50 can be combined with monochrome (or chromatic) calibration of
the prior art scanner. In general, before the prior art scanner
formally performs the document scan, it usually first performs a
monochrome (or chromatic) calibration. Calibration is performed by
scanning a monochrome (or chromatic) reference image to obtain the
monochrome (or chromatic) reference image signals to supply
information needed by the monochrome (or chromatic) calibration
unit. Therefore, the first and second reference signals 56, 58 can
be obtained directly during calibration scans of the prior art.
[0048] In contrast to the scanning method of the prior art scanner
10, the present invention scanning method can position the guiding
lens at different positions. The scanner then decides the best
position at which to scan the document, or it can use the
information from the reference signals to perform image processing
on the final document scan. In this manner, shadows and stripes on
the final output, due to digs or dust on the guiding lens can be
reduced, and the probability of a good scan increases.
[0049] Those skilled in the art will readily observe that numerous
modifications and alterations of the device may be made while
retaining the teachings of the invention. Accordingly, the above
disclosure should be construed as limited only by the metes and
bounds of the appended claims.
* * * * *