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Digital Camera Patent Abstract
A method and an apparatus of image dynamic response re-mapping and
a digital camera using the same. The apparatus first transforms
an original Bayer image data into new transformed image data on
a new image coordinate system, and then performs dynamic response
re-mapping for the new transformed image data to calculate a gain
modulated value. Finally, the apparatus adjusts the original Bayer
image data according to the gain modulated value and outputs adjusted
Bayer image data with dynamic response re-mapping. Because the apparatus
transforms the original Bayer image data into the new transformed
image data on the new image coordinate system in advance, it can
reduce the bad effect on performing the dynamic response re-mapping
on a high-frequency color signal and also keep the color coherence
in color processing.
Digital Camera Patent Claims
1. An apparatus of image dynamic response re-mapping for receiving
an original Bayer image data and performing the image dynamic response
re-mapping on the original Bayer image data to generate a modulated
Bayer image data, the apparatus comprising: a color coordinate transforming
unit for receiving the original Bayer image data and transforming
the original Bayer image data into a new transformed image data
on a new image coordinate system, the image data quantity of the
new transformed image data on the new image coordinate system being
smaller than the data quantity of the original Bayer image data;
a high gain generator for receiving the new transformed image data
and calculating a maximum gain from a high gain dynamic response
distribution curve according to data of a to-be-processed pixel;
a low gain generator for receiving the new transformed image data
and calculating a minimum gain from a low gain dynamic response
distribution curve according to the data of the to-be-processed
pixel; an image characteristic value generator for receiving the
new transformed image data, performing an image locality analysis
on an neighboring image of the to-be-processed pixel on the new
image coordinate system, and calculating a characteristic value
of the neighboring image, which comprises an average illumination
.DELTA.y, a illumination variability .delta.y and a histogram of
illumination; a weighting calculating unit for generating a first
weighting and a second weighting according to the characteristic
value, wherein the first weighting is inversely proportional to
the average illumination .DELTA.y, and the second weighting is directly
proportional to the illumination variability .delta.y and relates
to the histogram of illumination and the data of the to-be-processed
pixel; a gain modulated value calculating unit for calculating a
gain modulated value according the maximum gain, the minimum gain,
the first weighting and the second weighting; and an image synthesizing
unit for receiving the original Bayer image data and the gain modulated
value, and multiplying the original Bayer image data by the corresponding
gain modulated value to generate the modulated Bayer image data.
2. The apparatus according to claim 1, wherein the color coordinate
transforming unit extracts a maximum from each 2.times.2 pixel matrix
of the original Bayer image data as a single pixel of the new transformed
image data.
3. The apparatus according to claim 1, wherein the high gain generator
performs a .gamma. curve adjusting and generates the maximum gain
by a table look-up method.
4. The apparatus according to claim 1, wherein the low gain generator
performs a .gamma. curve adjusting and generates the minimum gain
by a table look-up method.
5. The apparatus according to claim 1, wherein the weighting calculating
unit generates the first weighting according to the equation: W1=c1*(2.sup.d-.DELTA.y)+c2(.delta.y),
wherein W1 denotes the first weighting, c1 and c2 are constants,
2.sup.d denotes a maximum gray-scale number of the image, .DELTA.y
denotes the average illumination, and .delta.y denotes the illumination
variability.
6. The apparatus according to claim 1, wherein the weighting calculating
unit generates the second weighting according to the following equation:
W2=c3*position(y at histogram), wherein W2 denotes the second weighting,
c3 is a constant, and position(y at histogram) denotes a position
of "y" on the histogram.
7. A method of image dynamic response re-mapping for receiving
an original Bayer image data and performing the image dynamic response
re-mapping on the original Bayer image data to generate modulated
Bayer image data, the method comprising: a color coordinate transforming
step for receiving the original Bayer image data and transforming
the original Bayer image data into a new transformed image data
on a new image coordinate system, wherein the quantity of the new
transformed image data on the new image coordinate system is smaller
than the data quantity of the original Bayer image data; a high
gain generating step for receiving the new transformed image data
and calculating a maximum gain from a high gain dynamic response
distribution curve according to data of a to-be-processed pixel;
a low gain generating step for receiving the new transformed image
data and calculating a minimum gain from a low gain dynamic response
distribution curve according to the data of the to-be-processed
pixel; an image characteristic value generating step for receiving
the new transformed image data, performing an image locality analysis
on a neighboring image of the to-be-processed pixel on the new image
coordinate system, and calculating a characteristic value of the
neighboring image, which comprises an average illumination .DELTA.y,
a illumination variability .delta.y and a histogram of illumination;
a weighting calculating step for generating a first weighting, which
is inversely proportional to the average illumination .DELTA.y,
and a second weighting, which is directly proportional to the illumination
variability .delta.y and relates to the histogram and the data of
the to-be-processed pixel, according to the characteristic value;
a modulated value calculating step for calculating a gain modulated
value according the maximum gain, the minimum gain, the first weighting
and the second weighting; and an image synthesizing step for receiving
the original Bayer image data and the gain modulated value, and
multiplying the original Bayer image data by the corresponding gain
modulated value to generate the modulated Bayer image data.
8. The method according to claim 7, wherein the color coordinate
transforming step extracts a maximum from each 2.times.2 pixel matrix
of the original Bayer image data as a single pixel of the new transformed
image data.
9. The method according to claim 7, wherein the high gain generating
step performs a .gamma. curve adjusting and generates the maximum
gain by a table look-up method.
10. The method according to claim 7, wherein the low gain generating
step performs a .gamma. curve adjusting and generates the minimum
gain by a table look-up method.
11. The method according to claim 7, wherein the weighting calculating
step generates the first weighting according to the equation: W1=c1*(2.sup.d-.DELTA.y)+c2(.delta.y),
wherein W1 denotes the first weighting, c1 and c2 are constants,
2.sup.d denotes a maximum gray-scale number of the image, .DELTA.y
denotes the average illumination, and .delta.y denotes the illumination
variability.
12. The method according to claim 7, wherein the weighting calculating
step generates the second weighting according to the following equation:
W2=c3*position(y at histogram), wherein W2 denotes the second weighting,
c3 is a constant, and position(y at histogram) denotes a position
of "y" on the histogram.
13. A digital camera with an image dynamic response re-mapping
function, the digital camera comprising: an image sensor for capturing
a to-be-shot image and then transforming the to-be-shot image into
an original Bayer image data; an image dynamic response re-mapping
unit for receiving the original Bayer image data and modulating
dynamic response of the original Bayer image data to generate modulated
Bayer image data; an image processing unit for receiving the modulated
Bayer image data and processing the modulated Bayer image data into
processed image data; an image compressing unit for receiving the
processed image data and compressing the processed image data into
compressed image data; a storage unit for receiving and storing
the compressed image data; and a display unit for receiving and
displaying the processed image data, wherein the image dynamic response
re-mapping unit comprises: a color coordinate transforming unit
for receiving the original Bayer image data and transforming the
original Bayer image data into new transformed image data on a new
image coordinate system, the image data quantity of the new transformed
image data on the new image coordinate system being smaller than
the data quantity of the original Bayer image data; a high gain
generator for receiving the new transformed image data and calculating
a maximum gain from a high gain dynamic response distribution curve
according to data of a to-be-processed pixel; a low gain generator
for receiving the new transformed image data and calculating a minimum
gain from a low gain dynamic response distribution curve according
to the data of the to-be-processed pixel; an image characteristic
value generator for receiving the new transformed image data, performing
an image locality analysis on an neighboring image of the to-be-processed
pixel on the new image coordinate system, and calculating a characteristic
value of the neighboring image, which comprising an average illumination
.DELTA.y, a illumination variability .delta.y and a histogram; a
weighting calculating unit for generating a first weighting and
a second weighting according to the characteristic value, wherein
the first weighting is inversely proportional to the average illumination
.DELTA.y, and the second weighting, which is directly proportional
to the illumination variability .delta.y and relates to the histogram
and the data of the to-be-processed pixel; a calculating unit for
calculating a gain modulated value according the maximum gain, the
minimum gain, the first weighting and the second weighting; and
an image synthesizing unit for receiving the original Bayer image
data and the gain modulated value, and multiplying the original
Bayer image data by the corresponding gain modulated value to generate
the modulated Bayer image data.
14. The digital camera according to claim 13, wherein the image
processing unit performs image reproducing, white balancing, color
interpolating, color correcting, RGB-to-YUV transforming on the
modulated Bayer image data.
Digital Camera Patent Description
[0001] This application claims the benefit of the filing date of
Taiwan Application Ser. No. 094107761, filed on Mar. 15, 2005, the
content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an image processing apparatus and
an image processing method, and more particularly to an apparatus
and a method of performing dynamic response re-mapping on a Bayer
image, and a digital camera using the same.
[0004] 2. Description of the Related Art
[0005] An apparatus composed of a digital camera and other image
processing apparatuses includes an image acquiring unit, an image
processing unit, an image displaying unit and an image compressing
unit. These units have different information amounts in processing
with the same image source, and have image losses during the image
processing procedure. Among these information losses, the gray-scale
loss tends to eliminate the detail texture of the image. That is,
the gray-scale loss tends to reduce the dynamic response range of
the image processing apparatus. Especially, if the dynamic range
of the gray-scale of the acquired image is very wide, for example,
a flash is adopted or a back-lighted shot is performed, a detail
brightness variation of the highlight or the shadow in the image
generated at the last stage cannot be shown due to the insufficient
information.
[0006] U.S. Pat. No. 6,256,424(which is named '424 patent) discloses
an image filter circuit utilizing the hardware architecture including
an IIR-type low-frequency filter for generating an unsharp image
for the dynamic range compression. The drawback of the '424 patent
is that each edge of the processed image may become a pseudo-edge
and cause distortion when the dynamic range compression ratio is
large. U.S. Pat. No. 6,807,316(which is named '316 patent) discloses
an image processing method and an image processing apparatus using
multiple low-frequency filters to generate an unsharp image for
the dynamic range compression, and can thus eliminate the drawback
of generating the pseudo-edge.
[0007] FIG. 1 shows the architecture of the image processing method
and apparatus of the '316 patent. As shown in FIG. 1, the image
processing apparatus utilize a first filtering process (Filtering
Process 1) and a second filtering process (Filtering Process 2)
to convert an input signal into a first unsharp image signal (Unsharp
Image signal 1) and a second unsharp image signal (Unsharp Image
signal 2), respectively. Then, a look-up-table synthesis (LUT Synthesis)
is performed to synthesize the first unsharp image signal and the
second unsharp image signal into a single image signal. Thereafter,
a look-up-table computation (LUT Computation) is performed to generate
a compensation signal. Finally, the input signal and the compensation
signal are summated to generate an output signal.
[0008] The above-mentioned technology mainly utilizes a low-pass
filter to separate a low-frequency signal from a high-frequency
signal of an original image, and then reduces a gain of the low-frequency
signal to compress the dynamic response range in the low-frequency
area of the original image. Finally, the compressed low-frequency
signal and the low-frequency area of the original image are synthesized
such that the high-frequency signal (i.e., the detail texture) of
the original image may be kept and the dynamic response range is
also compressed within the range of the information amount that
can be provided by an image processing unit. This technology has
the drawback that the frequency response of all images is continuous.
If some frequency simply serves as a dividing point for separating
the low-frequency signal from the high-frequency signal, the final
image may have the unsharp phenomenon as stated in the '424 patent.
Thus, multiple dividing points corresponding to several stages of
bands have to be used, as mentioned in the '316 patent, in order
to try to reduce the unsharp phenomenon. In addition, this technology
has another drawback that it is emphasized in the processing of
the low-frequency dynamic response, and does not process the gains
of the high-frequency signal in different highlight areas. Although
this method can properly reduce the contrast ratio of the image
with the high contrast ratio, it cannot provide a suitable gain
for the high-frequency components of the image in the dark state
and the highlight area. Thus, the final image becomes smooth but
lacks the image fidelity.
[0009] Furthermore, the digital camera and other image capturing
systems mainly include an image sensor, an image reproducing unit,
an image display unit and an image compressing unit, etc. The image
sensor can convert the brightness and the chroma of the natural
image into digital messages. Thereafter, these digital messages
are transformed into a digital image through the image reproducing,
display and compressing units. The information structure generated
in the image sensor of the current digital camera mainly corresponds
to the Bayer image. Each pixel in the Bayer image only can sense
one of three primary colors (R, G, B), as shown in FIG. 2. Thus,
the image reproducing unit is needed to reproduce the other two
color components and correct the colors such that the chroma of
the natural image can be reproduced. Because the brightness range
of the natural image is very wide, the digital camera system has
to enlarge the response range of the image sensor on the three primary
colors in order to capture more natural image messages. That is,
the gray-scale degree of the sensor has to be increased. When the
gray-scale degree of the image sensor is increased, the computation
amount of the subsequent image processing unit is also increased.
On the other hand, because the standard image compression format
(e.g., JPEG) and the gray-scale degree of the display are restricted,
the response range of the original sensor cannot be presented and
the information is thus lost. More particularly, when the digital
camera uses a flash or a back-lighted shot, the detailed brightness
variation in the high light region or the shadow region of the final
image cannot be presented due to the insufficient information. Thus,
the dynamic response range of the system cannot be enhanced.
SUMMARY OF THE INVENTION
[0010] It is therefore an object of the invention to provide a
method and a mechanism of performing dynamic response re-mapping
on a Bayer image such that image data captured by an image sensor
is free from being lost in the subsequent processing of an image
processing unit.
[0011] The invention achieves the above-identified object by providing
an apparatus of image dynamic response re-mapping for receiving
original Bayer image data and performing the image dynamic response
re-mapping on the original Bayer image data to generate modulated
Bayer image data. The apparatus includes a color coordinate transforming
unit, a high gain generator, a low gain generator, an image characteristic
value generator, a weighting calculating unit, a gain modulated
value calculating unit and an image synthesizing unit. The color
coordinate transforming unit receives the original Bayer image data
and transforms the original Bayer image data into new image data
on a new image coordinate system. An image data quantity of the
new image data on the new image coordinate system is smaller than
a data quantity of the original Bayer image data. The high gain
generator receives the new image data on the new image coordinate
system and calculates a maximum gain of a high gain dynamic response
distribution curve according to data of a to-be-processed pixel.
The low gain generator receives the new image data on the new image
coordinate system and calculates a minimum gain of a low gain dynamic
response distribution curve according to the data of the to-be-processed
pixel. The image characteristic value generator receives the new
image data on the new image coordinate system, performs an image
locality analysis on an neighboring image of the to-be-processed
pixel on the new image coordinate system, and calculates a characteristic
value of the neighboring image, which comprises an average illumination
.DELTA.y, a illumination variability .delta.y and a histogram of
illumination. The weighting calculating unit generates a first weighting,
which is inversely proportional to the average illumination .DELTA.y,
and a second weighting, which is directly proportional to the illumination
variability .delta.y and relates to the histogram and the data of
the to-be-processed pixel, according to the characteristic value.
The gain modulated value calculating unit calculates a gain modulated
value according the maximum gain, the minimum gain, the first weighting
and the second weighting. The image synthesizing unit receives the
original Bayer image data and the gain modulated value, and multiplies
the original Bayer image data by the corresponding gain modulated
value to generate the modulated Bayer image data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows the architecture of the image processing method
and apparatus disclosed in U.S. Pat. No. 6,807,316.
[0013] FIG. 2 shows a schematic illustration of a typical Bayer
image.
[0014] FIG. 3 shows the architecture of an apparatus of image dynamic
response re-mapping according to the invention.
[0015] FIG. 4 is a block diagram showing an image processing system
of a digital camera using the apparatus of image dynamic response
re-mapping of the invention.
[0016] FIG. 5 shows the flow chart of a method of image dynamic
response re-mapping of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The apparatus and method of image dynamic response re-mapping
(modulation) and the digital camera using the same according to
the invention will be described with reference to the accompanying
drawings.
[0018] The method of the invention of performing the dynamic response
re-mapping on a Bayer image is to transform a first Bayer image
into a new transformed image on a new image coordinate system, and
then to calculate a gain modulated value according to the new transformed
image. Finally, the original Bayer image is adjusted according to
the gain modulated value. The invention transforms the Bayer image
into the new transformed image on the new image coordinate system
for the purpose of reducing the bad effect caused by the high-frequency
color signal of the Bayer image on the subsequent dynamic response
re-mapping, and of keeping the color coherence in the color processing.
[0019] FIG. 3 shows the architecture of an apparatus 30 of image
dynamic response re-mapping according to the invention. Referring
to FIG. 3, the apparatus 30 includes a color coordinate transforming
unit 36, a high gain generator 31, a low gain generator 32, an image
characteristic value generator 33, a weighting calculating unit
34, a gain modulated value calculating unit 35 and an image synthesizing
unit 37. The gain modulated value calculating unit 35 includes two
multipliers 351 and 352 and one adder 353.
[0020] The color coordinate transforming unit 36 receives an original
Bayer image data and transforms it into a new transformed image
data on a new image coordinate system. For example, every 2*2 pixel
matrix in the original Bayer image data is transformed into a single
pixel on the new image coordinate system by taking a maximum in
every 2*2 pixel matrix as the pixel value on the new image coordinate
system, or by taking an average in every 2*2 pixel matrix as the
pixel value on the new image coordinate system. Thus, the data quantity
on the new image coordinate system is only one-fourth that on the
Bayer image system.
[0021] The high gain generator 31 and the low gain generator 32
receive the new transformed image data V, and respectively generate
a maximum gain G1 and a minimum gain G2 from the calculation of
the high gain dynamic response distribution curve and low gain dynamic
response distribution curve according to the pixel value of a to-be-processed
pixel. In general, the high gain generator 31 and the low gain generator
32 correspond to the so-called .gamma. curve adjustment. Because
the .gamma. curve adjustment is well know in the art, detailed descriptions
thereof will be omitted. The parameters for the .gamma. curve adjustment
may be set according to the user's preference. For example, the
high gain generator 31 and the low gain generator 32 may generate
the maximum and minimum gains G1 and G2 by way of look-up-table.
[0022] The image characteristic value generator 33 generates an
image characteristic value according to the new transformed image
data V. That is, the image characteristic value generator 33 performs
an image locality analysis on a neighboring image of the to-be-processed
pixel on the new image coordinate system. The image characteristic
of the image signal in this region is analyzed and then the characteristic
value of the neighboring image is calculated. The image characteristic
value includes an average illumination .DELTA.y, an illumination
variability .delta.y, and a histogram of illumination. The method
of calculating the average illumination .DELTA.y, the illumination
variability .delta.y and the histogram of the image is well known
in the art, and detailed descriptions thereof will be omitted. The
so-called local image denotes the pixels neighboring the to-be-processed
pixel, such as the image pixels in the 5*5 pixel matrix around the
to-be-processed pixel.
[0023] The weighting calculating unit 34 generates weightings W1
and W2 corresponding to the gains G1 and G2. The weighting calculating
unit 34 calculates the weightings W1 and W2 according to the image
characteristic value according to Equations (1) and (2). W1=c1*(2.sup.d-.DELTA.y)+c2(.delta.y)
(1),
[0024] wherein c1 and c2 are constants, 2.sup.d denotes the maximum
gray-scale number of the image, .DELTA.y denotes the average illumination
and .delta.y denotes the illumination variability. In this embodiment,
c1=1 and c2=16. When the image has the gray-scale number of 256,
d=8. W2=c3*position(y at histogram) (2),
[0025] wherein c3 is a constant and c3=16 in this embodiment, and
the position(y at histogram) denotes the position of y in the histogram
of illumination.
[0026] The multiplier 351 multiplies the gain G1 by the weighting
W1 to generate a weighting gain W1'. The multiplier 352 multiplies
the gain G2 by the weighting W2 to generate a weighting gain W2'.
Finally, the adder 353 adds the weighting gain W1' and the weighting
gain W2' together to generate a gain modulated value W3.
[0027] The image synthesizing unit 37 receives the original Bayer
image data and the corresponding gain modulated value W3, and generates
a modulated Bayer image. The image synthesizing unit 37 multiples
the pixel value of the original Bayer image by the corresponding
gain modulated value W3. That is, the pixels of the original Bayer
image in every 2*2 pixel matrix correspond to one gain modulated
value W3.
[0028] So, the apparatus of the invention transforms the Bayer
image data into the new image coordinate system so as to reduce
the bad effect of the high-frequency color signal of the Bayer image
on the subsequent dynamic response re-mapping, and also to keep
the color coherence in the color processing.
[0029] FIG. 4 is a block diagram showing an image processing system
40 of a digital camera using the apparatus of image dynamic response
re-mapping of the invention. Referring to FIG. 4, the image processing
system 40 of the digital camera includes an image sensor 41, a dynamic
response re-mapping unit 42, an image processing unit 43, an image
compressing unit 44, a storage unit 45 and a display unit 46.
[0030] The image sensor 41 captures a to-be-shot image and then
transforms it into digital data of a Bayer image. The image dynamic
response re-mapping unit 42 receives the Bayer image data and modulates
the dynamic response of the Bayer image data to generate a modulated
Bayer image data. The image processing unit 43 receives the modulated
Bayer image data and performs image processing, such as image reproducing,
white balancing, color interpolation, color correction, and RGB-to-YUV
transformation, on the image data. The image processing is well
known in the art, and detailed descriptions thereof will be omitted.
The image compressing unit 44 receives the image processed by the
image processing unit 43, compresses the image and then stores the
compressed image to the storage unit 45. The display unit 46 receives
and displays the image processed by the image processing unit 43.
Thus, the digital camera using the image processing apparatus of
the invention can enhance the detail brightness variation of the
high light region or the shadow region through the function of the
image dynamic modulation when a flash or a back-lighted shot is
utilized.
[0031] FIG. 5 is a flow chart showing a method of image dynamic
response re-mapping of the invention. As shown in FIG. 5, the method
of image dynamic response re-mapping includes the following steps.
[0032] Step S500: start.
[0033] Step S502: read an original Bayer image data.
[0034] Step S504: transform color coordinate. The system transforms
the original Bayer image data into new transformed image data on
a new image coordinate system. For example, every 2*2 pixel matrix
in the original Bayer image data is transformed into a single pixel
on the new image coordinate system. The transforming method is to
take a maximum from each 2*2 pixel matrix as a pixel value on the
new image coordinate system. Of course, the transform method may
also take the average. So, the data quantity on the new image coordinate
system is only one-fourth that on the Bayer image system.
[0035] Step S506: generate a characteristic value of a local image.
The system performs an image locality analysis on neighboring images
of the to-be-processed pixel on the new image coordinate system.
An image characteristic analyzing unit calculates the characteristic
value of the neighboring image according to the image signal of
this region. The characteristic value includes an average illumination
.DELTA.y, an illumination variability .delta.y and a histogram of
illumination.
[0036] Step S508: generate two weightings W1 and W2. The system
determines two weightings of the high and low gain dynamic response
distribution curves for the pixel according to the characteristic
value of the local image. The high gain curve can increase the image
brightness and may be used, for example, to enhance the brightness
of the dark state region. The low gain curve reduces the image brightness
and may be used, for example, to increase the contrast ratio of
the image. In this embodiment of the invention, the weighting of
the high gain curve is inversely proportional to the average illumination
.DELTA.y calculated by the characteristic analyzing unit, and directly
proportional to the illumination variability .delta.y. That is,
as the brightness variation in the dark state region of the image
gets larger, the weighting of the high gain curve increases, and
the weighting of the low gain curve relates to the histogram, which
is calculated by the characteristic analyzing unit, and the brightness
of the pixel. If the brightness of the pixel falls within the dark
state region of the histogram, the weighting of the low gain curve
increases.
[0037] First Weighting: W1=c1*(2.sup.d-.DELTA.y)+c2(.delta.y) (1)
[0038] wherein c1 and c2 are constants, 2.sup.d denotes the maximum
gray-scale number of the image, .DELTA.y denotes the average illumination,
and .delta.y denotes the illumination variability. In this embodiment,
c1=1 and c2=16. When the image has the gray-scale number of 256,
d=8.
[0039] Second Weighting: W2=c3*position(y at histogram) (2)
[0040] wherein c3 is a constant and c3=16 in this embodiment, and
position(y at histogram) denotes the position of y in the histogram.
[0041] Step S510: generate gains. The system calculates a maximum
gain G1 and a minimum gain G2 of the high and low gain dynamic response
distribution curves according to the data of the to-be-processed
pixel on the new image coordinate system.
[0042] Step S512: calculate a gain modulated value. The system
multiplies the two weightings W1 and W2 by the maximum and minimum
gains G1 and G2, respectively, to obtain W1' and W2', and then adds
W1' and W2' together to generate the gain modulated value W3. W1'=G1*W1
(3) W2=G2*W2 (4) W3=W1'+W2' (5)
[0043] Step S514: perform the image synthesis. The system performs
the image synthesis by multiplying the original Bayer image data
by the corresponding gain modulated value W3 and then outputting
the product as adjusted Bayer image data. In the color coordinate
transforming step, the 2*2 pixel matrix data in the original Bayer
image is transformed into single color data. So, the 2*2 pixel matrix
data of the original Bayer image is multiplied by the corresponding
gain modulated value W3 in the image synthesis.
[0044] Step S516: end.
[0045] Thus, the invention can avoid the unsharp drawback caused
in the prior art when the band gap separating point is used. Meanwhile,
the invention also provides a method of changing the gain for the
high-frequency signal of the image in different bright state regions.
The invention enhances the detail texture variation of the image
by changing the dynamic response distribution of the image so as
to reduce the reduction of the dynamic response range of the system,
which is caused by the information loss during the image processing
procedure. In addition, the image fidelity can be enhanced due to
the dynamic response re-mapping of the image.
[0046] While certain exemplary embodiments have been described
and shown in the accompanying drawings, it is to be understood that
such embodiments are merely illustrative of and not restrictive
on the broad invention, and that this invention not be limited to
the specific construction and arrangement shown and described, since
various other modifications may occur to those ordinarily skilled
in the art.
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