JP4439841B2 - Imaging apparatus and image processing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus using an imaging element and an image processing method thereof.
[0002]
[Prior art]
In recent years, with the advancement of digital signal processing technology and semiconductor technology, consumer digital video standards for digitally recording standard television, for example, NTSC and PAL video signals have been proposed. Digital video cameras in which a device and an imaging device are integrated have been commercialized. Some digital video cameras have a still image recording function by taking advantage of the feature of digital recording. Some have a digital I / F for connection to a computer or the like, and have a function of taking a captured image into the computer. In addition, there are some recording media that store captured image data, and a desired recording medium can be selected according to the intended use of the captured image.
[0003]
In such an image pickup apparatus, when a recorded image is reproduced on a television, the image size is determined by the digital video standard, for example, 720 × 480 pixels, but there is no problem, but the image is not received via a digital I / F. When transferring images to other media, a larger number of pixels may be required due to image quality problems.
[0004]
In addition, the number of pixels of the image sensor has increased as the resolution of the image sensor has increased, and in order to read the information of all pixels read by such an image sensor, the image sensor is driven by a higher frequency drive signal. However, such a high frequency drive signal leads to S / N degradation and increased power consumption.
[0005]
On the other hand, as one method of increasing the data rate of imaging information while keeping the driving frequency of the imaging device low, a CCD area sensor that is an area imaging device is used as the imaging device, and the imaging area is divided into a plurality of areas. There is a method of dividing and providing an independent charge transfer unit, amplifier and output terminal in each region, and reading out the imaging signals from each CCD in parallel.
[0006]
The disadvantage of this method is that the characteristics of the amplifier that amplifies the image pickup signal in each area and the external peripheral circuit are not uniform. There has been a problem that image quality degradation of the finally generated image occurs due to a problem such as a boundary line due to a level difference.
[0007]
As a method of reducing image quality degradation due to non-uniformity in each area, the correction coefficient is obtained by measuring the black level and standard white level of each area in advance, and the non-uniformity is corrected by this correction coefficient during imaging. A way to do it is considered.
[0008]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 06-133331
[0009]
[Problems to be solved by the invention]
However, in the conventional method, although the brightness levels of white and black are improved, saturation is not taken into consideration, so there is a difference in color tone at the boundary between regions due to the nonlinearity of each region of the area image sensor. The phenomenon of coming out may occur. This is not a problem especially when shooting a subject with sufficient illuminance, but when shooting a subject with low illuminance, it is necessary to increase the gain of the amplification of the video signal. As a result, a slight difference in color was enlarged, resulting in deterioration of image quality.
[0010]
The present invention has been made in view of the above-described conventional example, and an object thereof is to provide an imaging apparatus and an image processing method therefor, in which a difference in color in a boundary region of each area imaged by an area imaging element is reduced.
[0011]
[Means for Solving the Problems]
The imaging device of the present invention has the following configuration. That is,
An imaging apparatus comprising an area imaging device having a plurality of output terminals, and processing an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
Amplifying means for amplifying the image signal corresponding to each imaging region;
And color signal control means for controlling the saturation of the image signal in accordance with the gain of the amplification means.
[0012]
The imaging device of the present invention has the following configuration. That is,
An imaging apparatus comprising an area imaging device having a plurality of output terminals, and processing an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
The image signal corresponding to each imaging area , With different gain so that the brightness difference of the border of the imaging area is suppressed Amplifying means for amplifying;
Of the amplification means each Said according to the gain Corresponding to each imaging area And color signal control means for controlling the saturation of the image signal.
[0013]
The image processing method in the imaging apparatus of the present invention includes the following steps. That is, an image processing method in an imaging apparatus that includes an area imaging device having a plurality of output terminals and processes an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
An amplification step for amplifying an image signal corresponding to each imaging region;
And a color signal control step of controlling the saturation of the image signal in accordance with the gain of the amplification step.
[0014]
The image processing method in the imaging apparatus of the present invention includes the following steps. That is,
An image processing method in an imaging apparatus comprising an area imaging device having a plurality of output terminals, and processing an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
The image signal corresponding to each imaging area , With different gain so that the brightness difference of the border of the imaging area is suppressed An amplification step to amplify;
Of the amplification step each Said according to the gain Corresponding to each imaging area And a color signal control step for controlling the saturation of the image signal.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[Embodiment 1]
FIG. 1 is a block diagram schematically showing the configuration of a single-panel video camera according to Embodiment 1 of the present invention.
[0016]
In the figure, reference numeral 100 denotes a CCD area sensor, whose imaging area is divided into two, and has output terminals 107 and 108, respectively. Reference numerals 101 and 102 denote photoelectric conversion units and vertical transfer units. Reference numerals 103 and 104 denote horizontal transfer units. In accordance with the division of the imaging area of the CCD area sensor 100, separate imaging signals on the left and right sides of the approximate center of the screen. Is provided to process. Reference numerals 105 and 106 denote output amplifiers that amplify and output the left and right signal charges of the CCD area sensor 100. The signal charges corresponding to the left and right areas amplified by the output amplifiers 105 and 106 are output to the output terminals 107 and 106, respectively. 108. 109 and 110 are analog front ends that perform A / D conversion with correlated double samples, 111 and 112 are black level detection and black level correction units, 113 and 114 are gain adjustment units that adjust the gain, and 116 is two left and right units. A step evaluation value generation unit 117 for detecting non-uniformity between channels (two systems) is a screen synthesis unit that synthesizes two systems of image signals to generate one image. A control unit 115 controls the operation of the entire video camera. The control unit 115 includes a CPU 115a such as a microcomputer, and a program memory 115b that stores programs and data of the CPU 115a. A camera signal processing unit 118 includes a luminance level detection unit 120 that detects the luminance level of the video signal, and a color difference gain amplifier 121 that controls the gain of the amplifier of the color difference signal. The signal processed here is an output terminal 119. Is output from. Reference numeral 122 denotes a rewritable nonvolatile memory.
[0017]
Next, the operation of the video camera according to the first embodiment having the above configuration will be described.
[0018]
The subject image formed on the CCD area sensor 100 is converted into an electrical signal by the photoelectric conversion units 101 and 102, then divided into two systems by the horizontal transfer paths 103 and 104, and supplied to the output amplifiers 105 and 106. The These output amplifiers 105 and 106 amplify the signal charges corresponding to the left and right imaging areas of the CCD area sensor 100, respectively, and output them through output terminals 107 and 108. Here, an imaging signal obtained from the output terminal 107 is referred to as a left channel signal, and an imaging signal obtained from the output terminal 108 is referred to as a right channel signal.
[0019]
These left and right channel signals are subjected to correlated double sample processing and A / D conversion by analog front ends 109 and 110, respectively, and then supplied to black level detection and correction units 111 and 112. The black level detection and correction units 111 and 112 respectively use the dummy signal portion or the optical black signal portion of each channel signal so that the black level of the left and right channel imaging signals coincides with “0” of the digital data. Black level correction is performed. Thereby, the error of the offset component between the left and right channel signals is removed.
[0020]
The gain adjustment sections 113 and 114 perform gain adjustment on the left and right channel signals whose black levels have been corrected in this way. A gain value applied during the gain adjustment is supplied from the control unit 115. In a conventional video camera, gain adjustment of the amount of image pickup signal in a low illuminance environment is performed by an analog circuit. However, as in the first embodiment, in a video camera that handles two systems of imaging signals consisting of left and right channels, if the gain adjustment is performed by an analog circuit, it may cause nonuniformity of imaging signals between the left and right channels. For this reason, in the first embodiment, the gain adjustment of the left and right channels is performed by digital calculation using the gain adjustment units 113 and 114. This eliminates the influence of variations in circuit characteristics corresponding to the left and right channels, temporal variation, and temperature variation.
[0021]
Further, not only the gain adjustment for adjusting the brightness of the image but also the correction of the gain error between the two systems consisting of the left and right channels is performed here. In general, the difference in gain between the left and right channels (two systems) depends on the output level of the CCD area sensor 100.
[0022]
FIG. 3 is a diagram illustrating an example of a gain difference between two systems (left and right channels).
[0023]
3 represents the signal level of the left channel of the CCD 100, and the vertical axis represents the ratio of the signal of the input signal (left channel) of the gain adjusting unit 114 to the signal of the input signal (right channel) of the gain adjusting unit 113, that is, 2. The signal level gain difference between systems is shown. For example, assuming that the signal level of the left channel of the CCD 100 when an object of a certain brightness is imaged is L0 and the signal level of the right channel is L0right, the gain ratio E0 at this time is given by the following equation (1).
[0024]
E0 = L0right / L0 ... Formula (1)
As shown in FIG. 3, since the relationship between the signal level (horizontal axis) and the gain difference (vertical axis) is not constant, the gain correction amount is not a fixed value, but is changed according to the gain adjustment amount. There is a need. In the first embodiment, the reference level Lref is set for the signal after gain adjustment. Regardless of the gain adjustment amount, the level difference between the left and right channels is always “0” regardless of the gain adjustment amount. Gain correction is performed so as to match Lref. As this Lref, a gray level of about 75% is selected after γ correction with respect to the reference white.
[0025]
For example, when the signal level of the left channel of the CCD 100 is L0 and the gain adjustment amount is such that the output level of the gain adjustment unit 114 becomes Lref, the gain A0 given to the gain adjustment unit 114 of the left channel is expressed by the following equation (2 ).
[0026]
A0 = Lref / L0 ... Formula (2)
The gain A0right given to the right channel gain adjusting unit 113 at this time can be expressed by the following equation (3), where the gain correction amount is C0.
[0027]
A0right = A0 × C0 ... Formula (3)
C0 is obtained by the following equation (4) from the equations (1) to (3).
[0028]
C0 = 1 / E0 ... Formula (4)
Similarly, when the signal level of the left channel of the CCD 100 is L1, the gain correction amount C1 when the gain adjustment amount is such that the output level of the gain adjusting unit 114 becomes Lref is obtained by the following equation.
[0029]
C1 = 1 / E1 (5)
Here, as shown in FIG. 3, E1 indicates a gain difference from the signal level (L1right) of the right channel when the signal level of the left channel is L1 (E1 = L1right / L1).
[0030]
FIG. 4 is a diagram for explaining the characteristics of the gain correction amount with respect to the gain adjustment amount.
[0031]
In FIG. 4, A0 represents the gain given to the gain adjustment unit 114 when the left channel signal level is L0, and A1 represents the gain given to the gain adjustment unit 114 when the left channel signal level is L1. Yes. The gain correction amounts C0 and C1 correspond to the correction amounts represented by the above-described equations (4) and (5), respectively. This correction characteristic differs for each component of the CCD 100 or the analog front end 109, 110.
[0032]
Next, measurement of gain correction characteristics will be described.
[0033]
The step evaluation value generation unit 116 calculates the evaluation value of the screen step based on the pixel value in the rectangular area designated near the boundary of the divided area of the CCD area sensor 100 and outputs the evaluation value to the control unit 115.
[0034]
FIG. 2 is a diagram for explaining an example of the rectangular area.
[0035]
As shown in the figure, rectangular areas 203 and 204 are set in the vicinity of the boundary between the two divided areas 201 and 202 of the CCD area sensor 100. The pixel values in these rectangular areas 203 and 204 are used for evaluating the screen level difference. The CCD 100 has an on-chip color filter attached to a pixel portion in order to capture a color image with a single plate. The on-chip color filter has an RGB arrangement as shown by 205 in FIG. The step evaluation value generation unit 116 selects a pixel value of one color, for example, G signal, and calculates an average value within the rectangular area, and this average value becomes the evaluation value of the screen step.
[0036]
When measuring the gain correction characteristic, an object with uniform brightness is imaged by the CCD area sensor 100, and the control unit 115 sets the same gain (A0, A1) multiplier to the gain adjustment units 113 and 114. . The average level of the pixels in the rectangular area 203 is output to the control unit 115 as the left channel signal level, and the average level of the pixels in the rectangular area 204 is output as the right channel signal level. The control unit 115 calculates the right channel gain correction amount (A0right) using the left channel level (L0) as a reference according to the above-described equation (3). Gain correction data is generated by performing such measurement at a predetermined time interval on the signal level output from the CCD 100. The control unit 115 stores the gain correction data thus generated in a rewritable nonvolatile memory 122 such as an EEPROM (Electrically Erasable Programmable Read Only Memory). Such generation of gain correction data is executed, for example, during factory adjustment.
[0037]
FIG. 5 is a diagram illustrating the output characteristics of the analog front ends 109 and 110 with respect to the brightness of the subject in the video camera according to the first embodiment.
[0038]
In the figure, reference numeral 502 denotes an ideal characteristic. According to this ideal characteristic, the outputs of the analog front ends 109 and 110 change linearly with respect to the brightness of the subject. However, in general, the linearity of the system from the CCD area sensor 100 to A / D conversion deteriorates due to various factors, and may have a complicated nonlinear characteristic as shown by 501 in FIG. 5, for example. In the above-described gain correction, a case where correction is performed based on the detected G signal has been described as an example, but the same can be applied to the R and B signals. However, in that case, there may be a nonlinear characteristic different from that in the case of the G signal. For this reason, there is a problem that the hue changes with the brightness of the subject. Furthermore, when such a nonlinear characteristic is approximated by a low-order function, an optimal approximate solution cannot be obtained in some cases. Although coloring by this non-linear characteristic is not conspicuous in normal photographing, when the gain is increased in the amplifier circuit when the illuminance of the subject is low, the difference between the RGB signals becomes noticeable. Therefore, when gain is increased in the gain adjusting units 113 and 114, a process for improving coloring is required.
[0039]
FIG. 6 is a diagram for explaining the gain control of the color difference gain amplifier 121 performed according to the gain control in the gain adjustment units 113 and 114, in which the horizontal axis represents the gain given to the gain adjustment units 113 and 114, and the vertical axis represents the color difference. The color saturation of the gain amplifier 121, that is, the gain in the color difference gain amplifier 121 is shown. A in the figure indicates control characteristics based on the relationship between the gain and color saturation in the color difference gain amplifier 121.
[0040]
The control unit 115 detects the luminance level of the photographed image based on the information from the luminance level detection unit 120. If the luminance level is low, the control unit 115 increases the gain given to the gain adjustment units 113 and 114, and conversely. When the luminance level is high, a feedback loop is formed by reducing the gain applied to the gain adjusting sections 113 and 114, and exposure control is performed. For example, when a subject with sufficiently high illuminance is photographed, the gain given to the gain adjusters 113 and 114 is 0 dB. When a subject with extremely low illuminance is photographed, the gain given to the gain adjusters 113 and 114 is increased to 10 dB. The exposure level of the image photographed by such control is kept appropriate.
[0041]
Next, control based on the color saturation information from the color difference gain amplifier 121 will be described.
[0042]
Normally, the color difference signal is output from the output terminal 119 at a specified signal level, but the output signal level in the color difference gain amplifier 121 can be varied by control by the control unit 115. That is, in FIG. 6, 100% on the vertical axis represents a normal output level, and 40% on the vertical axis represents output from the output terminal 119 at a signal level that is 0.4 times the normal level.
[0043]
FIG. 7 is a flowchart for explaining processing by the control unit 115 of the video camera according to the first embodiment. Here, exposure control using the gain adjustment units 113 and 114 and output level control processing of the color difference gain amplifier 121 are performed. It is shown. A program for executing this processing is stored in the program memory 115b of the control unit 115, and is executed under the control of the CPU 115a based on this program.
[0044]
When the control is started, first, in step S1, it is determined whether or not the luminance of the imaging signal detected by the luminance level detection unit 120 is higher than a reference value. When it is higher than the reference value, the process proceeds to step S3, and the gains of the gain adjusting units 113 and 114 are lowered. On the other hand, if it is lower than the reference value in step S1, the process proceeds to step S2, and the gains of the gain adjusting units 113 and 114 are increased. When step S2 or S3 is executed in this way, the process proceeds to step S4, and the gain of the color difference gain amplifier 121 is obtained by calculation from the gain determined in step S2 or S3 (for example, as shown in the example of FIG. 6). In step S5, the color difference gain amplifier 121 is controlled in accordance with the obtained gain.
[0045]
In the gain control of the color difference gain amplifier 121, the CPU 115a has a table storing gains to be given to the gain adjusting units 113 and 114 and gains of the color difference gain amplifier 121 corresponding to the gains. The gain of the color difference gain amplifier 121 is determined by performing interpolation processing based on the above. This table is stored in the memory 115b of the control unit 115.
[0046]
This process will be described with reference to FIG. 6. The color saturation (gain) of the color difference gain amplifier 121 is controlled according to the control characteristic A according to the gain (horizontal axis) given to the gain adjusting units 113 and 114. That is, when the gain is 0 dB, it is 100%, and when the gain given to the gain adjusting units 113 and 114 becomes 3 dB, the gain starts decreasing, and the gain given to the gain adjusting units 113 and 114 decreases substantially linearly until 9 dB. This serves to suppress noise components that have increased due to an increase in the gain of the previous stage signal. And when the gain becomes 9 dB, it decreases to 40%. At higher gains, the color saturation (gain) of the color difference gain amplifier 121 remains at 40%. That is, in the state where the gains of the gain adjusting units 113 and 114 are low, the color of the captured image is dark, but the color becomes lighter as the gains of the gain adjusting units 113 and 114 are increased, and the coloring due to the non-linear characteristics is noticeable. Work to lose.
[0047]
Note that the numerical values in FIG. 6 are merely examples, and the numerical values may not be as they are, and the gains of the gain adjusting units 113 and 114 may be set by the user.
[0048]
As described above, according to the first embodiment, even when a subject with low illuminance is photographed by changing the saturation of the video signal to be finally output according to the gain when the video signal is amplified. The boundary due to the difference in the output signal of each area from the area image sensor is made inconspicuous, and the color step between the areas can be eliminated.
[0049]
[Embodiment 2]
FIG. 8 is a block diagram showing the configuration of the video camera according to Embodiment 2 of the present invention. The parts common to those in FIG.
[0050]
A subject image formed on the CCD area sensor 100 by an imaging optical system (not shown) is converted into an electrical signal by the CCD 100, and output terminals 107, according to drive pulses supplied from a drive timing generation circuit (not shown). 108. These left and right channel image signals are subjected to analog signal processing by the analog front ends 109 and 110 and are then A / D converted and supplied to the black level correction circuits 911 and 912 and the black level difference detection circuit 913. The black level difference detection circuit 913 detects a black level difference from the image signals of the left and right channels, and calculates a correction coefficient for each channel. These correction coefficients are supplied to the black level correction circuits 911 and 912 to correct the difference in black level. For detection of these black level differences, signals of optical black pixels of the CCD sensor 100 are used. The detection of the black level difference and the calculation of the correction value are performed only once at a predetermined time, and the correction coefficient obtained in this way is stored in the memory 920, so that the detection and correction value calculation are performed at the time of subsequent photographing. And the black level difference is corrected based on the correction coefficient stored in the memory 920.
[0051]
Next, each signal whose black level is corrected in this way is supplied to a white level correction circuit 914, 915 and a white level difference detection circuit 916. The white level difference detection circuit 914 detects a white level difference from the image signals of the left and right channels, and calculates a correction coefficient for each channel. These correction coefficients are supplied to the white level correction circuits 914 and 915 to correct the difference in white level. To detect this white level difference, the CCD sensor 100 is irradiated with uniform light that provides a standard white level, and the image signal at that time is used. The detection of the white level difference and the calculation of the correction value are performed only once at a predetermined time, and the correction coefficient obtained in this way is stored in the memory 921, so that these detections are performed at the time of subsequent photographing. Instead, the white level difference is corrected using the correction coefficient stored in the memory 921.
[0052]
The signal whose white level is corrected in this way is combined into a single image by combining the left and right images in the screen combining circuit 917, and then the γ correction processing, contour correction processing, and color correction processing are performed in the camera signal processing circuit 918. Are output from the output terminal 919 as a luminance signal and a color difference signal. A low luminance color suppression circuit 922 suppresses a color signal according to the luminance level in the image.
[0053]
In the first embodiment described above, generally, the linearity of the system from the CCD area sensor 100 to the A / D conversions 109 and 110 deteriorates due to various factors, for example, a complex nonlinearity as indicated by 501 in FIG. In the case where the R and B signals have non-linear characteristics different from those of the G signal, the color difference between the divided areas appears. This difference in color is not noticeable because it is relatively small with respect to the signal level in the portion with a high luminance level in the image, but becomes relatively large with respect to the signal level in a portion with a low luminance level in the image Therefore, it becomes a problem. That is, when there is a dark part in the image at the boundary of the divided area, the boundary becomes conspicuous at that part.
[0054]
Therefore, in the second embodiment, this problem is solved by providing a low luminance color suppression circuit 922 in the camera signal processing unit 918.
[0055]
FIG. 9 is a block diagram illustrating the low luminance color suppression circuit 922 according to the second embodiment.
[0056]
In the figure, reference numeral 1001 denotes a color difference matrix circuit, which converts RGB signals into color difference signals. Reference numeral 1002 denotes a low luminance detection circuit, which detects a low luminance portion of the luminance signal Y in the image. Reference numeral 1003 denotes a color suppression circuit that suppresses the signal level of the color difference signals (RY, RY), which is the output of the color difference matrix circuit 1001. Reference numeral 1004 denotes a Y / C • MIX circuit which synthesizes the color difference signals (R−Y, R−Y) and the luminance signal Y and outputs them as a video signal. The low luminance detection circuit 1002 generates luminance information from the input luminance signal Y and outputs a suppression signal 1005 to the color suppression circuit 1003.
[0057]
On the other hand, the color difference signal output from the color difference matrix circuit 1001 is suppressed to a predetermined signal level by the color suppression circuit 1003 in accordance with the suppression signal 1005. The suppressed color difference signals (R−Y, R−Y) and the luminance signal Y are combined in the Y / C • MIX circuit 1004 and output as a video signal. The low luminance detection circuit 1002 outputs a color suppression signal 1005 in accordance with, for example, the characteristics shown in FIG.
[0058]
FIG. 10 is a graph showing the relationship between the luminance signal level and the color suppression level in the low luminance detection circuit 1002 according to the second embodiment.
[0059]
In the drawing, the horizontal axis indicates the signal level of the detected luminance signal Y, and the vertical axis indicates the color difference signal level that is the output of the color suppression circuit 1003. As shown in FIG. 10, in the dark portion where the luminance signal level in the image is extremely small, the output color difference signal is very close to “0”. Until the luminance signal level reaches Y0, the output color difference signal increases approximately linearly to CR, and for luminance signals larger than Y0, the color difference signal remains CR. Therefore, since the color is light in the dark part in the image, even if there is a dark part at the boundary part of each divided area, the difference in coloring between the areas becomes inconspicuous.
[0060]
In FIG. 9, the color signal output from the color difference matrix circuit 1001 has been described as the color difference signal (RY, RY), but the color signal may be other than the color difference signal. In FIG. 10, the change in the luminance signal level and the color suppression is shown by an oblique straight line, but this change may be stepwise.
[0061]
FIG. 11 is a flowchart for explaining processing in the camera signal processing unit 918 according to the second embodiment.
[0062]
Here, first, in step S11, it is determined whether or not the luminance detected by the low luminance detection circuit 1002 is equal to or lower than a predetermined luminance. If so, the process proceeds to step S12, and the value of the suppression signal 1005 is determined according to the detected luminance. In step S13, the determined suppression signal 1005 is output to the color suppression circuit 1003 to suppress the color component of the color difference signal. Then, the process proceeds to step S15.
[0063]
On the other hand, if the luminance detected by the low luminance detection circuit 1002 is not less than the predetermined luminance in step S11, the process proceeds to step S14, and the suppression signal 1005 is almost set to “0” or is not output. As a result, the color difference component is output as it is. Thus, the process proceeds to step S15, where the luminance signal component and the color signal component are combined, and the combined result is output.
[0064]
As described above, according to the second embodiment, the signal level of the entire image signal is adjusted according to the luminance level of the low luminance part in the image, and the saturation of the image signal is changed according to the adjustment. As a result, even in a low-luminance portion of the image, the boundary due to the difference in luminance and color of the image signal of each area from the area image sensor can be made inconspicuous, and a conspicuous step generated between the areas can be eliminated.
[0065]
[Other embodiments]
As described above, the object of the present invention is to provide a system or apparatus with a storage medium storing software program codes for realizing the functions of the embodiment, and the computer of the system or apparatus (or CPU or MPU) stores it. It is also achieved by reading and executing the program code stored on the medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. As a storage medium for supplying such a program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM Etc. can be used.
[0066]
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) running on the computer based on the instruction of the program code Includes a case where the function of the above-described embodiment is realized by performing part or all of the actual processing.
[0067]
Furthermore, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, the function is determined based on the instruction of the program code. This includes the case where the CPU of the expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0068]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the color difference in the boundary region between the regions imaged by the area image sensor.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a video camera according to Embodiment 1 of the present invention.
FIG. 2 is a diagram illustrating a rectangular region at a region boundary portion of the area image sensor according to the present embodiment.
FIG. 3 is a diagram for explaining a relationship between imaging signal levels of left and right channels and a gain difference between channels in the present embodiment.
FIG. 4 is a diagram for explaining a relationship between a gain adjustment amount and a gain adjustment amount in a gain adjustment unit according to the present embodiment;
FIG. 5 is a diagram for explaining the relationship between the brightness of a subject and the output of an analog front end according to the present embodiment.
FIG. 6 is a diagram for explaining a gain (color saturation) of a color difference gain amplifier with respect to a gain in a gain adjustment unit according to the first embodiment;
FIG. 7 is a flowchart illustrating gain control of the color difference gain amplifier accompanying gain adjustment in the video camera according to Embodiment 1 of the present invention;
FIG. 8 is a block diagram showing a schematic configuration of a video camera according to Embodiment 2 of the present invention.
FIG. 9 is a block diagram illustrating a configuration of a low luminance color suppression circuit according to a second embodiment of the present invention.
FIG. 10 is a diagram for explaining control characteristics in the low luminance color suppression circuit according to the second embodiment;
FIG. 11 is a flowchart illustrating a control process in a camera signal processing unit according to the second embodiment.

Claims (14)

An imaging apparatus comprising an area imaging device having a plurality of output terminals, and processing an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
Amplifying means for amplifying the image signal corresponding to each imaging region with a different gain so as to suppress the brightness difference at the boundary of the imaging region ;
Color signal control means for controlling the saturation of the image signal corresponding to each imaging region according to each gain of the amplification means;
An imaging device comprising:   The area imaging device divides an imaging region in a horizontal direction, outputs an image signal corresponding to the divided region from the output terminal, and the amplifying unit outputs a plurality of output signals from each output terminal of the area imaging device The imaging apparatus according to claim 1, wherein the image signals are independently amplified.   The imaging apparatus according to claim 1, wherein the color signal control unit decreases the saturation of the image signal as the gain in the amplification unit increases. Brightness detection means for detecting the brightness of each image signal corresponding to each imaging region;
Control means for increasing the gain when the brightness detected by the brightness detection means is less than or equal to a predetermined amount, and for reducing the gain when the brightness detected by the brightness detection means is greater than or equal to the predetermined amount. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an image pickup apparatus. An imaging apparatus comprising an area imaging device having a plurality of output terminals, and processing an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
Amplifying means for amplifying the image signal corresponding to each imaging region;
Color signal control means for controlling the saturation of the image signal in accordance with the gain of the amplification means;
Brightness detection means for detecting the brightness of each image signal corresponding to each imaging region;
Control means for increasing the gain when the brightness detected by the brightness detection means is less than or equal to a predetermined amount, and for reducing the gain when the brightness detected by the brightness detection means is greater than or equal to the predetermined amount. And
Wherein said control means includes a storage means for storing correction information of the gain, the storage means you and controls so as to change the gain by referring to the correction information stored in an imaging apparatus. 6. The imaging apparatus according to claim 5, wherein the color signal control unit decreases the saturation of the image signal as the gain in the amplification unit increases. An image processing method in an imaging apparatus comprising an area imaging device having a plurality of output terminals, and processing an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
An amplification process for amplifying the image signal corresponding to each imaging region with a different gain so that the brightness difference at the boundary of the imaging region is suppressed ;
A color signal control step for controlling the saturation of the image signal corresponding to each imaging region in accordance with each gain of the amplification step;
An image processing method comprising:   The area imaging device divides an imaging region in a horizontal direction, outputs an image signal corresponding to the divided region from the output terminal, and the amplifying unit outputs a plurality of output signals from each output terminal of the area imaging device The image processing method according to claim 7, wherein each of the image signals is independently amplified.   9. The image processing method according to claim 7, wherein, in the color signal control step, the saturation of the image signal is reduced as the gain in the amplification step increases. A luminance detection step of detecting the luminance of each image signal corresponding to each imaging region;
And a control step of increasing the gain when the luminance detected in the luminance detection step is equal to or less than a predetermined amount, and decreasing the gain when the luminance detected in the luminance detection step is equal to or greater than the predetermined amount. The image processing method according to any one of claims 7 to 9. An image processing method in an imaging apparatus comprising an area imaging device having a plurality of output terminals, and processing an image signal corresponding to each imaging region output from each output terminal of the area imaging device,
An amplification step for amplifying an image signal corresponding to each imaging region;
A color signal control step of controlling the saturation of the image signal according to the gain of the amplification step;
A luminance detection step of detecting the luminance of each image signal corresponding to each imaging region;
A control step of increasing the gain when the luminance detected in the luminance detection step is equal to or less than a predetermined amount, and decreasing the gain when the luminance detected in the luminance detection step is equal to or greater than the predetermined amount. And
Wherein in the control step, and stores the correction information of the gain memory, images processed how to characterized in that referring to the correction information stored in the memory is controlled so as to change the gain. 12. The image processing method according to claim 11, wherein, in the color signal control step, the saturation of the image signal is reduced as the gain in the amplification step increases.   A program for causing a computer to execute the image processing method according to any one of claims 7 to 12.   A computer-readable storage medium storing the program according to claim 13.

Images