JP3911883B2 - Sensitivity compensation method and sensitivity compensation apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensitivity compensation method and a sensitivity compensation apparatus used in an imaging apparatus such as a digital camera provided with an imaging element.
[0002]
[Prior art]
Conventionally, for example, in a digital camera, an image captured by an image sensor such as a CCD is stored in a memory. In actual photographing, color correction control such as exposure control and white balance is performed according to the average sensitivity of the image sensor. In recent years, in addition to photographing under sunlight, a specific Color correction control such as exposure control and white balance corresponding to the difference in photographing light is performed in addition to the sensitivity of the image sensor so that appropriate photographing can be performed even under photographing light.
[0003]
[Problems to be solved by the invention]
However, in the above-described control of a conventional digital camera, a relatively good image can be taken even in shooting under various shooting light. However, the sensitivity of the imaging device is an average of the devices used. Since the sensitivity is used, the control result at the time of photographing is not necessarily expected to be ideal due to the variation in sensitivity between solids of the actually used image sensor.
[0004]
The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a sensitivity compensation method and a sensitivity compensation apparatus that can compensate for variations in sensitivity of an image sensor for each product.
[0012]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, in the invention of claim 1, the image pickup signal for each RGB color component separated from the output signal of the image pickup means is increased / decreased by an individually increase / decrease means,Combining image signals for each RGB color component output from each increment / decrement meansBased on the color signal generated from the imaging signal laterThe gain of each increase / decrease meansAuto white balance mode to be adjusted, and fixed white balance that sets a fixed value determined in advance corresponding to the light source of the specific color as the gain of each increase / decrease means when shooting under the light source of the specific color In the sensitivity compensation method of the image pickup apparatus having the mode, prior to shooting in the fixed white balance mode, the subject of the reference color in the auto white balance mode is pre-shot, and when shooting in the fixed white balance mode, Obtained based on each adjustment value of the gain of each increase / decrease means adjusted at the time of previous photographing and a known change rate of the gain of each increase / decrease means when the color of the subject changes from the reference color to the specific color. The gain values of the increase / decrease means corresponding to the specific color are set as the fixed values. It was.
[0013]
In such a method, the difference between the sensitivity of each of the RGB color components of the imaging unit and the reference sensitivity is based on a known rate of change based on the difference between the reference color and the specific color. While the ratio between the gains of the respective increasing / decreasing means is maintained, it is reflected in the fixed value of the gain of each increasing / decreasing means set at the time of photographing under the light source of the specific color. Therefore, by performing pre-photographing on a white subject, it is possible to eliminate variations in spectral sensitivity characteristics between solid-state image sensors from white balance controlled under a specific color light source.
[0014]
Claims2In this invention, the change rate of the color temperature when the light changes from the reference color to the specific color is used as the known change rate. In such a method, the difference between the sensitivity of each of the RGB color components of the image pickup means and the reference sensitivity is based on a known change rate of the color temperature based on the difference between the reference color and the specific color, and the light source of the specific color. It is reflected in the fixed value of the gain of each increasing / decreasing means set at the time of shooting with. Therefore, by performing pre-photographing on a white subject, it is possible to eliminate variation in sensitivity for each RGB color component between solids of the image sensor from white balance controlled under a specific color light source.
[0015]
  In the invention of claim 3, the image pickup signal for each of the RGB color components separated from the output signal of the image pickup means is increased or decreased by the increase / decrease means provided individually,Combining image signals for each RGB color component output from each increment / decrement meansBased on the color signal generated from the imaging signal laterThe gain of each increase / decrease meansAuto white balance mode to be adjusted, and fixed white balance that sets a fixed value determined in advance corresponding to the light source of the specific color as the gain of each increase / decrease means when shooting under the light source of the specific color A sensitivity compensation device for use in an imaging device having a mode, wherein the acquisition unit acquires each adjustment value of the gain of each increase / decrease unit that is adjusted during pre-shooting with respect to a reference color subject in the auto white balance mode; Reference value storage means for storing a known change rate of the gain of each increase / decrease means when the color of the subject changes from the reference color to the specific color, and the gain of each increase / decrease means acquired by the acquisition means Corresponding to the specific color on the basis of each adjustment value and a known change rate of the gain of each increase / decrease means stored in the reference value storage means Serial search of the gain value of each adjusting unit and shall the respective gain values and control means for setting as the fixed value.
[0016]
In such a configuration, the difference between the sensitivity of each of the RGB color components of the imaging unit and the reference sensitivity is determined based on a known change rate based on the difference between the reference color and the specific color. While maintaining the ratio between the gains of the respective increasing / decreasing means at the time of the pre-shooting, it is reflected in the fixed value of the gain of each increasing / decreasing means set at the time of shooting under the light source of the specific color. Therefore, by performing pre-photographing on a white subject, it is possible to eliminate variations in spectral sensitivity characteristics between solid-state image sensors from white balance controlled under a specific color light source.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an imaging processing unit 1 that constitutes a sensitivity compensation device of the present invention in a digital camera equipped with a strobe that emits photographing auxiliary light.
[0018]
In this imaging processing unit 1, the amount of incident light from the optical system is adjusted by the diaphragm 2, and a subject image is formed on the CCD 3 through the diaphragm 2, and an analog imaging signal corresponding to the subject image is output from the CCD 3. Is output. This analog output is amplified by the AGC amplifier 4 and sent to the CCD data capturing unit 5 where it is converted into a digital signal. The imaging signal converted into the digital signal is processed by the Y / C processing unit 6 for luminance signal (Y signal), color signal, and the like, and then sent to the image data processing system. In addition, a part of the Y signal output from the Y / C processing unit 6 is input to the AE calculation unit 7, and the AE calculation unit 7 obtains an appropriate aperture value based on the luminance input as the Y signal. The shutter speed and the gain of the AGC amplifier 4 are calculated. Then, based on the shutter control signal sent from the AE calculation unit 7 according to the calculation result, the electronic shutter control unit 8 drives the CCD 3 to control the electronic shutter amount which is the charge accumulation time of the CCD 3. At the same time, the gain of the AGC amplifier 4 is adjusted in accordance with the gain control signal sent from the AE calculation unit 7, thereby performing exposure control.
[0019]
A mode setting signal sent from the shooting mode setting unit 9 is input to the AE calculation unit 7. This mode setting signal is set to any one of the exposure control modes of the digital camera, that is, the three types of exposure control modes of “automatic exposure correction”, “fixed exposure”, and “fixed exposure data setting” in the present embodiment. It is a signal indicating whether or not. The automatic exposure correction mode is a general AE mode that adjusts the aperture value, shutter speed, and gain of the AGC amplifier 4 based on the Y signal described above. The fixed exposure mode is a mode prepared for flash photography, and is a mode for obtaining an optimum exposure under a strobe light. When the mode is set, the AE calculation unit 7 controls the aperture 2 and the electronic shutter based on various data stored in the fixed exposure setting memory 10 which is a rewritable nonvolatile memory in addition to the luminance input as the Y signal. Control unit 8 and the like.
[0020]
FIG. 2 is an explanatory diagram showing data stored in the fixed exposure setting memory 10, in which a fixed aperture value Fx, a fixed electronic shutter amount Sx, a fixed gain value Gx, and a gain correction value k are stored. . Each data excluding the gain correction value k is exposure control data for obtaining an appropriate exposure when performing strobe photography using a CCD having standard sensitivity. The fixed electronic shutter amount Sx is an amount that can cover the light emission time of the strobe because the amount of light is small in the shooting environment at the time of strobe shooting and the exposure is mostly due to the strobe light. In this embodiment, “1” is stored as the initial value in the correction gain value k. The fixed exposure data setting mode is normally a mode that cannot be set by the user and can be set in the manufacturing process of the digital camera. A mode setting signal indicating that this mode has been set is sent from the shooting mode setting unit 9. By being sent to the exposure error calculation unit 11 or the like, the imaging processing unit 1 performs an operation described later.
[0021]
Next, in the present embodiment configured as described above, the operation when the fixed exposure data setting mode is set during the adjustment work performed in the manufacturing process of the digital camera will be described with reference to the flowchart of FIG. The adjustment operation is performed at a predetermined brightness that allows the light receiving unit (lens not shown) of the digital camera to obtain an appropriate exposure by controlling the electronic shutter amount when the aperture value is fixed at the maximum value (for example, F2.8). It is assumed that the process is performed under a condition directed to a light source (pseudo-sunlight) that emits light.
[0022]
That is, when the fixed exposure data setting mode is set, the AE calculation unit 7 sets the aperture value to the maximum value, fixes the gain of the AGC amplifier 4 to the fixed gain value Gx (step SA1), and electronic shutter AE control for sequentially increasing / decreasing only the amount is started (step SA2). Then, the AE control is performed until the calculation result that sets the luminance input as the Y signal from the Y / C processing unit 6 to the determined appropriate luminance converges (exposure adjustment ends). Eventually, when the calculation result converges (YES in step SA2), the exposure error calculation unit 11 calculates the amount of electronic shutter converged here and the fixed electronic shutter stored in the fixed exposure setting memory 10 shown in FIG. An error from the amount Sx is calculated (step SA4). Subsequently, the exposure error calculation unit 11 converts the calculated error (electronic shutter amount) into a value corresponding to the gain of the AGC amplifier 4, and calculates a coefficient for increasing or decreasing the fixed gain value Gx by the converted value. The gain correction value k calculated and stored in the fixed exposure setting memory 10 is rewritten to the calculated coefficient (step SA5), and the fixed exposure data setting mode is terminated. That is, the gain correction value k is “1” or more when the sensitivity of the CCD 3 is lower than the standard, and is “1” or less when the sensitivity is higher than the standard.
[0023]
FIG. 4 is a flowchart showing an operation in the present embodiment when a fixed exposure mode for flash photography is set by the user after the adjustment work described above is performed. That is, when the fixed exposure mode is set, the AE calculation unit 7 first sets the fixed aperture value Fx and the fixed electronic shutter stored in the fixed exposure setting memory 10 shown in FIG. 2 as the aperture value and the electronic shutter amount. The amount Sx is set (step SB1). Further, the AE calculation unit 7 performs a calculation (fixed gain value Gx × correction gain value k) for correcting the fixed gain value Gx with the gain correction value k, and sets the calculated value as the gain of the AGC amplifier 4 ( SB2), the process ends.
[0024]
Accordingly, when the sensitivity of the CCD 3 is lower than the standard, the fixed gain value of the AGC amplifier 4 is increased correspondingly, and when the sensitivity is higher than the standard, it is decreased. That is, even if there is a variation in sensitivity between the solid bodies in the CCD 3, when photographing under strobe light, the electronic shutter amount adjusted during the above-described adjustment operation and the reference fixed electronic shutter amount Sx The error is reflected in the set gain of the AGC amplifier 4 at the time of shooting, and the variation is eliminated. Therefore, variation in sensitivity of the CCD 3 for each product can be compensated, and as a result, the exposure control result under a specific light source can be expected and ideal for all products.
[0025]
Further, since the gain of the AGC amplifier 4 is set to a gain value suitable for the sensitivity of the actual CCD 3 only during the above-described operation in the fixed exposure mode (in the present embodiment, at the time of flash photography), for example, There are the following advantages compared with the case where the gain is corrected at the time of all photographing. That is, the gain is increased when the sensitivity of the CCD 3 is lower than the standard, but if the gain is increased during shooting other than strobe shooting, noise in the image signal increases and the image quality deteriorates. On the other hand, according to the present embodiment, such a problem can be prevented in advance.
[0026]
In this embodiment, the case where the fixed exposure mode is for flash photography has been described. However, when a fixed exposure mode corresponding to photography under another specific light source is prepared, that is, the aperture value or When other shooting modes for fixing the electronic shutter amount are prepared, exposure control data corresponding to such a shooting mode is stored in the fixed exposure setting memory 10 or the like, and the above-described fixed exposure data setting mode is set. If this is performed for each shooting mode, the same effects as in the present embodiment can be obtained in other shooting modes. Even in this case, the adjustment work described above needs to be performed only once, and the adjustment work is easy.
[0027]
Assuming that the fixed exposure mode is for flash photography, the CCD 3 compensates for variations in sensitivity of the CCD 3 based on the error between the electronic shutter amount during the adjustment operation described above and the reference fixed electronic shutter amount Sx. As described above, in the case where the aperture value is adjusted during the adjustment operation, in addition to the error between the electronic shutter amount and the reference fixed electronic shutter amount Sx, the aperture value during the adjustment operation and the reference aperture It is also possible to compensate for variations in sensitivity of the CCD 3 based on an error from the value Fx. Further, if the aperture value can be finely adjusted in the aperture 2, it is possible to compensate for variations in sensitivity of the CCD 3 based only on the error between the aperture value during the adjustment operation and the reference aperture value Fx. In addition, when exposure control values other than the electronic shutter amount and aperture value are present during exposure control during adjustment work, the sensitivity of the CCD 3 is adjusted based on the exposure control target adjustment value and its reference value. It is also possible to compensate for variations.
[0028]
Further, based on the gain correction value k obtained during the operation in the fixed exposure data setting mode (manufacturing process), the fixed gain value Gx is determined in accordance with the actual sensitivity of the CCD 3 during the operation in the fixed exposure mode (during shooting). In the fixed exposure data setting mode, the final corrected gain value is stored in the fixed exposure setting memory 10 as the fixed gain value Gx at the time of operation in the fixed exposure data setting mode. Also good.
[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 5 is a block diagram showing the imaging processing unit 21 of the digital camera constituting another sensitivity compensation apparatus of the present invention.
[0029]
Also in the image pickup processing unit 21, the analog image pickup signal output from the CCD (not shown) is converted into a digital signal by the CCD data capturing unit 22 in the same manner as described with reference to FIG. The imaging signal converted into the digital signal is separated into R, G, B signals by the RGB separation unit 23, and an R gain adjustment unit 24 and a G gain adjustment unit 25 that perform weighting (multiplication processing) on each signal. , And B gain adjustment unit 26, respectively. Outputs from these are processed by the Y / C processing unit 27 for processing of luminance signals, color signals, and the like, and then sent to the image data processing system. A through image display is sequentially performed on a liquid crystal monitor (not shown) of the digital camera.
[0030]
On the other hand, a part of the color signal output from the Y / C processing unit 27 is input to the white balance calculation unit 28, and the white balance calculation unit 28 uses the R gain adjustment unit 24, the G gain adjustment unit 25, The gain (multiplication value) of the B gain adjustment unit 26 is calculated, and the weighting (ratio between them) of each color component R, G, B is controlled based on the calculation result. A mode setting signal sent from the white balance mode setting unit 29 is input to the white balance calculation unit 28. This mode setting signal is a signal indicating which of the “auto white balance”, “fixed white balance”, and “fixed data adjustment” modes is selected by a setting dial (not shown) of the digital camera. The white balance calculation unit 28 performs the above-described operation when the auto white balance mode is set.
[0031]
The fixed white balance mode includes the specific photographing light described in the related art, sunlight (color temperature about 5500 ° K), shade (color temperature about 10000 ° K), tungsten light (color temperature) in this embodiment. White balance suitable for about 2500 ° K) is performed. When this mode is set, the white balance calculation unit 28 stops the operation based on the color signal sent from the Y / C processing unit 27 described above, and the white balance fixed data memory 30 which is a rewritable nonvolatile memory. Based on the stored fixed tone data of the color components R, G, and B, the gains of the R gain adjusting unit 24, G gain adjusting unit 25, and B gain adjusting unit 26 are controlled. FIG. 6 is an explanatory diagram showing the fixed color tone data A. The fixed color tone data A is composed of fixed gain values Rg1 to Rg3, Gg1 to Gg3, and Bg1 to Bg3 corresponding to the types of photographing light. Each of these fixed gain values is a value for obtaining an appropriate white balance at the time of photographing under the photographing light.
[0032]
In addition, the fixed data adjustment mode is a mode that cannot be normally set by the user but is set in the manufacturing process of the digital camera. When this mode is set, the white balance calculation unit 28 performs the same operation as when the auto white balance mode is set. At the same time, the setting signal output from the white balance mode setting unit 29 is also sent to the fixed data adjustment setting unit 31, and the fixed data adjustment setting unit 31 stores the light source correction shown in FIG. Based on data B etc., the operation | movement concerning the white balance setting mentioned later is performed. The light source correction data B includes a reference white color temperature (3500 ° K in the present embodiment), a color temperature of each photographing light selected in the fixed white balance mode, that is, a color temperature of sunlight (5500). ° K), shaded color temperature (10000 ° K), and tungsten light color temperature (2500 ° K), respectively, and conversion coefficients k1, k2, and k3.
[0033]
Next, in the present embodiment configured as described above, the white balance setting operation when the fixed data adjustment mode is set during the adjustment work performed in the manufacturing process of the digital camera will be described with reference to the flowchart of FIG. . Note that the adjustment work is premised on that the light receiving unit (lens not shown) of the digital camera is performed under the condition where the light is directed toward the reference white color (color temperature 3500 ° K).
[0034]
That is, when the fixed data adjustment mode is set, the white balance calculation unit 28 starts the above-described auto white balance operation in which the gray area becomes a correct gray expression based on the color signal output from the Y / C processing unit 27. (Step SC1). The operation is continued until the calculation result converges, that is, until the gain values of the R gain adjusting unit 24, G gain adjusting unit 25, and B gain adjusting unit 26 for white as the reference are determined. (NO in step SC2). When the calculation result eventually converges (YES in step SC2), the fixed data adjustment setting unit 31 sends the light source correction data B (see FIG. 7) read from the light source correction parameter memory 32 and the white balance calculation unit 28. Based on the calculation result (converged calculation result), the fixed color tone data A (see FIG. 6) described above, that is, fixed corresponding to each photographing light (sunlight, shade, tungsten light) that can be selected in the fixed white balance mode. Gain values Rg1 to Rg3, Gg1 to Gg3, and Bg1 to Bg3 are calculated (step SC3). Here, calculation is performed by multiplying the gain value of each gain adjusting unit 24, 25, 26 converged in step SC2 by a conversion coefficient corresponding to each photographing light. For example, assuming that the gain values of the gain adjusting units 24, 25, and 26 converged in step SC2 are Rgn, Ggn, and Bgn, the shaded fixed gain values Rg2, Gg2, and Bg2 are Rgn × k2, Ggn × k2, respectively. , Bgn × k2. When the calculation is completed, the calculation result is continuously written in the white balance fixed data memory 30 (step SC4), and the fixed data adjustment mode is ended.
[0035]
That is, in such processing, the gain values (adjustment values) of the gain adjustment units 24, 25, and 26 obtained in a state where the auto white balance operation is performed on the reference white color are weighted (ratio) ), And shooting under sunlight, shade, and tungsten light based on the coefficients (k1 to k3) that make each color temperature of sunlight, shade, and tungsten light a standard white color temperature. Convert to a fixed gain value at.
[0036]
When the above-described fixed white balance mode is set after the end of the fixed data adjustment mode, the white balance calculation unit 28 corresponds to any of sunlight, shade, and tungsten light selected at that time. The fixed gain value to be read is read from the white balance fixed data memory 30, and the gain values of the R gain adjusting unit 24, G gain adjusting unit 25, and B gain adjusting unit 26 are controlled to the read gain values. Therefore, the weights of the color components R, G, and B corresponding to the sunlight, shade, and tungsten light selected at that time are the ratios obtained in the fixed data adjustment mode.
[0037]
For this reason, when white balance control is performed under each photographing light (light source of a specific color), even if there is a variation in spectral sensitivity characteristics between the solid bodies of the CCD 3, it can be eliminated. Therefore, it is possible to compensate for variations in spectral sensitivity characteristics between products, and as a result, it is possible to make the expected white balance control result under a specific photographing light for all products. . Further, as in the present embodiment, even when a plurality of types of photographing light that can be selected in the fixed white balance mode are prepared, if the adjustment work in the fixed data adjustment mode described above is performed once, Adjustments can be made for all of the photographing light. Therefore, even when there are a plurality of selectable photographing lights, the adjustment work is extremely simple.
[0038]
In the present embodiment, the fixed gain values of the R gain adjusting unit 24, the G gain adjusting unit 25, and the B gain adjusting unit 26 are calculated for all the color components R, G, and B for each type of photographing light. Then, it is written in the white balance fixed data memory 30 (steps SC3 and SC4). For example, the gain values Gg1 to Gg3 of the color component G are used as a reference, and the gain values Rg1 of the color components R and B are used as a ratio to this. To determine Rg3, Bg1 to Bg3, the gain values Gg1 to Gg3 of the color component G are stored in the white balance fixed data memory 30 as specified values from the beginning, and in the above-described fixed data adjustment mode, other colors are stored. Only the gain values of the components R and B need be calculated and stored.
[0039]
In the present embodiment, the fixed gain values of the color components R, G, and B are acquired in the fixed data adjustment mode and stored in the white balance fixed data memory 30 at that time. It can also be. That is, the reference value of the fixed gain value of all the color components is stored in advance in the white balance fixed data memory 30, and in the fixed data adjustment mode, the reference value is obtained by the auto white balance operation for the reference white. Correction data for correcting to a fixed gain value is stored in the white balance fixed data memory 30 together with the reference value. In the subsequent fixed white balance mode, a calculation for correcting the reference value by the correction data is performed, and the R gain adjusting unit 24, the G gain adjusting unit 25, and the B gain adjusting unit 26 are controlled by a gain value obtained by the calculation. Control. The effect mentioned above is acquired also by this.
[Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 9 is a block diagram showing the imaging processing unit 41 of the digital camera according to the present embodiment. In the following description, the same parts as those shown in FIG.
[0040]
That is, the imaging processing unit 41 includes a fixed white balance setting unit 42 instead of the fixed data adjustment setting unit 31 and the light source correction parameter memory 32 described with reference to FIG. The fixed white balance setting unit 42 is accompanied by an auto white balance operation in which the gray area is calculated based on the color signal output from the Y / C processing unit 27 and the gray region is processed into a correct gray expression. The calculation result (gain values set in the R, G, and B gain adjusting units 24, 25, and 26) and the mode setting signal from the white balance mode setting unit 29 are input. This mode setting signal is a signal indicating which mode of “auto white balance”, “fixed white balance”, or “white balance setting” is selected by a setting dial (not shown) of the digital camera. The white balance mode setting unit 29 receives an operation signal of an adjustment stop switch (not shown) assigned to any key or the like of the digital camera. Then, an adjustment stop signal is sent from the white balance mode setting unit 29 to the white balance calculation unit 28 and the fixed white balance setting unit 42. Further, the white balance fixed data memory 30 has fixed tone data similar to that shown in FIG. 6, that is, R, G, and B gains corresponding to shooting light prepared in advance that can be selected in the fixed white balance mode. The gain values to be set in the adjustment units 24, 25, and 26 are stored, and the fixed color tone data sent from the fixed white balance setting unit 42 can be stored along with the operation in the white balance setting mode to be described later.
[0041]
In the present embodiment configured as described above, the operation when the white balance setting mode is selected will be described with reference to the flowchart of FIG. Here, the user colors the light-receiving unit (lens not shown) of the digital camera with an arbitrary specific color such as a desired blue color (a white board under a desired color light source or a desired color). A case where the white balance setting mode is selected in a state where it is directed toward the board) will be described.
[0042]
That is, when the white balance setting mode is set, the white balance calculation unit 28 starts an auto white balance operation based on the color signal output from the Y / C processing unit 27 described above (step SD1). Next, it is determined whether or not the adjustment end switch is operated (step SD2). If the adjustment end switch is not pressed, the operation is continued until the calculation result in the auto white balance operation is converged ( NO in step SD3). Even during this time, the output of the Y / C processing unit 27 is sent to an image data processing system (not shown), and a through image display is sequentially performed on the liquid crystal monitor. When the calculation result converges (YES in step SD3), the calculation result (gain values for R, G, and B) is sent to the fixed white balance setting unit 42, and the fixed white balance setting unit 42 After the calculation result is newly written in the fixed data memory 30 as fixed tone data corresponding to a specific color (SD4), the operation ends in the white balance setting mode.
[0043]
On the other hand, if the adjustment end switch is pressed even before the calculation result converges (YES in step SD2), the auto white balance operation is in progress (a state in which the white balance is not completely drawn and the color fog remains). Even if it is interrupted, at the same time, the gains of the R, G, and B gain adjusters 24, 25, and 26 calculated at that time are newly written as fixed tone data corresponding to the specific color. After (SD4), the operation ends in the white balance setting mode.
[0044]
Therefore, the user can automatically set the white balance used at the time of photographing under a specific photographing light (blue light or the like) that is not prepared at the beginning of use, and the usability is improved. For example, when shooting under sunlight, if the fixed white balance mode is set and blue set by the user is selected as the specific color, the subject is intentionally emphasized in red (blue complementary color). Can also be taken.
[0045]
In addition, as described above, when the user wants to intentionally take a picture in which the subject is reddish when taking a picture under sunlight, the user can perform a subtle hue adjustment by performing the following operation. That is, set the white balance with blue as the specific color in advance, and then set the fixed white balance mode with blue selected as the specific color, then with the light receiving unit (lens) facing the actual subject. Then, the operation of the fixed data adjustment mode described above is started again. Then, the color tone in the process of pulling in the white balance is confirmed on the liquid crystal monitor, and when a desired color tone is obtained, a predetermined adjustment end switch is pressed. As a result, fine hue adjustment is possible.
[0046]
Although the embodiment described above shows the case where the present invention is applied to a digital camera, the present invention can also be applied to other imaging devices such as a digital video camera. Even in such a case, the effects described above can be obtained.
[0049]
【The invention's effect】
As described above, in the present invention,The difference between the sensitivity of each of the RGB color components of the image pickup means and the reference sensitivity is determined based on the known change rate based on the difference between the reference color and the specific color. While preserving the ratio between gains, it is reflected in the fixed value of the gain of each increase / decrease means set when shooting under a light source of a specific color, and specified by performing pre-shooting on a white subject It was made possible to eliminate variations in spectral sensitivity characteristics between solids of the image sensor from white balance controlled under a color light source. Therefore, it is possible to compensate for variations in sensitivity with respect to the color of the image sensor for each product. As a result, the white balance control result under a specific light source can be expected and ideal for all products.
[0050]
[Brief description of the drawings]
FIG. 1 is a block configuration diagram illustrating an imaging processing unit of a digital camera according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing data in a constant exposure setting memory.
FIG. 3 is a flowchart showing an operation in a fixed exposure data setting mode.
FIG. 4 is a flowchart showing an operation in a fixed exposure mode.
FIG. 5 is a block configuration diagram showing an imaging processing unit of a digital camera according to a second embodiment of the present invention.
FIG. 6 is an explanatory diagram showing fixed color tone data in a white balance fixed data memory;
FIG. 7 is an explanatory diagram showing light source correction data in a light source correction parameter memory.
FIG. 8 is a flowchart showing an operation in a fixed data adjustment mode.
FIG. 9 is a block configuration diagram illustrating an imaging processing unit of a digital camera according to a third embodiment of the present invention.
FIG. 10 is a flowchart showing an operation in a white balance setting mode according to the embodiment;
[Explanation of symbols]
1 Imaging processing unit
3 CCD3
4 AGC amplifier
7 AE calculator
8 Electronic shutter controller
9 Shooting mode setting section
10 Fixed exposure setting memory
21 Imaging processing unit
28 White balance calculator
30 White balance fixed data memory
31 Fixed data adjustment setting section
32 Light source correction parameter memory

Claims (3)

The imaging after the imaging signals for each RGB color component separated from the output signals of the imaging means are increased / decreased by individually increasing / decreasing means, and the imaging signals for each RGB color component output from each increasing / decreasing means are combined. Auto white balance mode that adjusts the gain of each increase / decrease unit based on the color signal generated from the signal, and fixed fixed in advance corresponding to the light source of the specific color when shooting under the light source of the specific color In a sensitivity compensation method for an imaging apparatus having a fixed white balance mode for setting a value to the gain of each increase / decrease unit,
Prior to shooting in the fixed white balance mode, pre-shooting is performed on the subject of the reference color in the auto white balance mode. Each of the increasing / decreasing means corresponding to the specific color obtained based on each adjustment value and a known change rate of the gain of each increasing / decreasing means when the color of the subject changes from the reference color to the specific color. A sensitivity compensation method, wherein each gain value is set as the fixed value.   The sensitivity compensation method according to claim 6, wherein a change rate of color temperature when light changes from the reference color to the specific color is used as the known change rate. The imaging after the imaging signals for each RGB color component separated from the output signals of the imaging means are increased / decreased by individually increasing / decreasing means, and the imaging signals for each RGB color component output from each increasing / decreasing means are combined. Auto white balance mode that adjusts the gain of each increase / decrease unit based on the color signal generated from the signal, and fixed fixed in advance corresponding to the light source of the specific color when shooting under the light source of the specific color A sensitivity compensator used for an imaging apparatus having a fixed white balance mode for setting a value to a gain of each of the increase / decrease means,
Acquisition means for acquiring each adjustment value of the gain of each of the increase / decrease means adjusted at the time of pre-shooting for the subject of the reference color by the auto white balance mode;
Reference value storage means for storing a known rate of change in gain of each of the increase / decrease means when the color of the subject changes from the reference color to the specific color;
Based on each adjustment value of the gain of each increase / decrease means acquired by the acquisition means and a known change rate of the gain of each increase / decrease means stored in the reference value storage means, the corresponding to the specific color And a control means for obtaining each gain value of each increase / decrease means and setting each gain value as the fixed value.

Images