JP4692872B2 - Image processing apparatus and program - Google Patents

Description

The present invention relates to an image processing apparatus and a program capable of easily performing gain control processing such as white balance without being influenced by the spectral characteristics of light source light .

With conventional digital cameras, the image of the captured subject appears greenish under fluorescent light and reddish under incandescent light, so the difference in color tone that varies depending on the light source is corrected, and the whiteness is the same regardless of the light source. The white balance (WB) control was performed to make it visible.
In order to adjust the white balance, the color temperature of the light source is required. However, it is broadly detected from the external photometry method in which a separate three-color RGB sensor for color temperature detection is provided and the RGB ratio of the CCD image signal. There is an internal metering method. In the internal photometry method, the achromatic color portion in the imaging screen is extracted and integrated, and adjusted so that the ratios of the RGB color difference components are equal. In the external photometry method, the balance of the color difference components of the RGB lines or (R− The color difference signal gain is adjusted so that the average and integral values of (Y) and (B−Y) become zero. Alternatively, when the color temperature is high, the gain of R is increased and the gain of B is decreased, and when the color temperature is low, the reverse control is performed.

  Patent Document 1 listed below discloses an invention of a camera device. Specifically, it is determined whether or not the light source is a fluorescent lamp. If it is determined that the light source is a fluorescent lamp, the white balance adjustment signal and the offset control voltage signal are added or subtracted and subtracted to obtain a simple and good white. Balance adjustment is performed.

  Patent Document 2 below discloses an invention that is a white balance circuit. Specifically, a detection unit that detects the spectral intensity of the RGB three primary colors and a detection unit that detects the intensity of the bright line spectrum are provided, and the spectrum is extremely unevenly distributed by calculating based on both outputs and controlling the white balance. Appropriate white balance can be obtained even for a light source of a discharge tube system such as a fluorescent lamp.

  Patent Document 3 listed below discloses an invention that is a spectral sensitivity correction mechanism of a photoelectric colorimeter. Specifically, it has three light receiving systems for measuring tristimulus values, and a corrected light receiving system having a spectral sensitivity different from the spectral sensitivity of the three light receiving systems, and outputs each of the three light receiving systems to the output of the light receiving system. By adding or subtracting the signal multiplied by the correction coefficient to the output of the other two light receiving systems, approximating the spectral sensitivity characteristic of the light receiving system to the given spectral sensitivity characteristic, and further correcting the residual error by the correction light receiving system The measurement accuracy can be remarkably improved.

Patent Publication No. 2502502 (refer to the right column, the fourth column, the 17th line to the (3) item, the right column, the sixth column, the 23rd line).

Patent gazette Japanese Patent Publication No. Sho 62-50026 (see (1) right column, second term, line 29 to (3) left column, fifth term, 30th line)

Japanese Patent Publication No. 2671414 (Refer to paragraph (3), left column, paragraph 5, line 8 to line (3), right column, paragraph 10, paragraph 11)

However, the conventional digital camera has the following problems.
(1) The WB control based on the RGB ratio is based on the same principle as a tristimulus photoelectric colorimeter, and the spectral sensitivity of the three light receiving systems is defined by the visual relative luminous sensitivity characteristics and CIE (International Institute of Illumination) 1931. If it is adapted to the RGB tristimulus color matching function, the correct chromaticity coordinates and color temperature can be measured, and accurate WB control should be possible based on this. It is difficult to match the transmittance and spectral sensitivity characteristics of the light-receiving unit to the color matching function, and even though analog WB control is possible, the accuracy is low for obtaining numerical values such as the color temperature, so the color temperature is highly accurate. There is a problem of performing WB control in response to the above.
In addition, there is no problem with light sources with gentle spectral distribution such as sunlight and incandescent lamps, but it cannot be measured well with light sources such as fluorescent lamps where the spectral characteristics are uneven and the emission line spectrum is remarkable. There is a problem of obtaining a color temperature.

  (2) Further, according to the invention described in Patent Document 1, when it is determined that the lamp is a fluorescent lamp from flicker or the like, the white balance adjustment signal and the offset control voltage signal are added and subtracted and subtracted. White balance can be adjusted, but various types of products with different color temperatures of 3000K to 8000K, such as daylight color, daylight white, white, warm white, light bulb color, and three-wavelength light emission of each color, can be used even with white fluorescent lamps. However, the color temperature cannot be set simply by distinguishing it from a fluorescent lamp, and there is a problem that an appropriate color temperature is set even in such a case.

(3) According to the invention described in Patent Document 2, a detection unit that detects the spectral intensity of the RGB three primary colors and a detection unit that detects the intensity of the bright line spectrum are provided. By controlling the balance, it is possible to obtain an appropriate white balance even for light sources of discharge tube systems such as fluorescent lamps whose spectrum is extremely unevenly distributed. Providing a spectrum-dedicated detector or the like is complicated and expensive, and there is a problem of simple and low cost.
In addition, when a plurality of types of light sources are mixed or a light source with new characteristics cannot be handled.

(4) According to the invention described in Patent Document 3 below, it is a dedicated measuring instrument that can perform high-precision color measurement, but can only be measured after an expert calibrates correctly using a calibrated standard light source or the like. Even the simplest photoelectric colorimeter is as expensive as several hundred thousand yen or more, and it is large and expensive to be incorporated for WB control of a portable camera.
In addition, when obtaining color information from a tristimulus photoelectric colorimeter or an image signal, it is difficult to match spectral sensitivity characteristics to a color matching function, and it has not been possible to cope with a discharge light source such as a fluorescent lamp.

  (5) Since the color temperature cannot be specified even if the WB can be adjusted, when performing the WB bracketing shooting, the color temperature, etc., is set in the same manner as when setting the exposure bracketing shooting to ± 3 EV or the like. It is not possible to specify the adjustment of the shooting conditions by setting a specific correction value, or to perform control corresponding to it, and to set the color temperature etc. specifically to ± 3 EV etc. in exposure bracketing shooting There was a problem of performing WB bracketing with specific settings.

  (6) Further, an interchangeable lens or an external filter is used, a zoom lens or an automatic exposure is built in, and the transmittance or the imaging device for each wavelength of the optical system is determined by the position and combination of the optical system. There are many controls that dynamically change the sensitivity of the optical system, but the changes in the spectral transmittance and reflectance of these optical systems and the spectral sensitivity of the imaging unit are due to the WB by the conventional CCD internal photometry method and external photometry methods such as RGB sensors. There was also a problem that it could not be handled by control. Even if the color temperature of the light source light and the color temperature of the photographic lens, color filter, etc. are known, it seems that these synthesized chromaticity coordinates and color temperatures are intermediate values on the chromaticity diagram. However, the additive color mixing principle does not apply between the spectral energy characteristics of light and the spectral transmittance of the filter, so even if white can be adjusted to white, it affects the reproducibility of other colors. I was sorry.

Therefore, the present invention has been made in view of such conventional problems , and an image processing apparatus capable of easily performing gain control processing such as white balance without being affected by the spectral characteristics or the like of light source light, and The purpose is to provide a program .

For achieve the above object, a first aspect of the present invention, an acquisition unit for acquiring an image signal, and Table示制control means Ru display the image of the obtained image signal by the pre-Symbol obtaining means on the display means, the user designating means for designating a partial area of the image displayed on the display means, calculation detecting means that to calculate the chromaticity coordinates of the partial region from the image signal of a portion designated region by previous SL designating means And the display control means displays the chromaticity diagram together with the image of the imaging signal and the chromaticity coordinates calculated by the calculation means on the chromaticity diagram with a coordinate cursor, and the user is displayed on the display means. and setting means for setting the chromaticity coordinates of the part designated area by the specifying means by adding or subtracting the correction coordinates cursor indicating a chromaticity coordinates of a chromaticity diagram to a desired value, by the calculation detecting means Calculated chromaticity coordinates of the partial area And white balance control means for controlling white balance by controlling the gain of the imaging signal acquired by the acquisition means so that the chromaticity coordinates set by the setting means are obtained. To do.

The invention of claim 2, wherein the acquisition device for acquiring an image signal, and a computer for controlling an image processing apparatus having a display device, on the display device an image of the obtained image signal by the pre-Symbol acquisition device Table示制control function Ru is displayed, the user is the display device to specify function for designating a partial region of the displayed image, before Symbol specify features of some from the image signal of a portion designated area region by calculated out function to calculate the chromaticity coordinates, the display control function, the chromaticity coordinates calculated by the calculation function diagram chromaticity diagram and the chromaticity along with the image of the image signal is displayed in the coordinate cursor, The user sets the chromaticity coordinates of the partial area designated by the designation function to a desired value by correcting the coordinate cursor indicating the chromaticity coordinates on the chromaticity diagram displayed on the display device. setting function and, the calculated The white balance is controlled by controlling the gain of the imaging signal acquired by the acquisition device so that the chromaticity coordinates of the partial area calculated by the function become the chromaticity coordinates set by the setting function. This is a program for realizing the white balance control function.

According to the present invention, easily without being affected by the spectral characteristics of the light source light and the like can perform the gain control processing such as white balance.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
[First embodiment]
A. Configuration of Digital Camera FIG. 1 is a block diagram showing an electrical schematic configuration of a digital camera 1 that implements the white balance device of the present invention.
The digital camera 1 includes an imaging lens 2, a drive circuit 3, a diaphragm shutter 4, a vertical driver 5, a TG (timing generator) 6, a CCD 7, a sample hold circuit 8, an analog / digital converter 9, a color separation circuit 10, and a gain adjustment unit. 11, image signal processing unit 12, memory 13, control circuit 14, display unit 15, key input unit 16, prism diffraction grating 17, sensor array 18, driver amplifier 19, analog-digital converter 20, energy distribution table memory 21, The information memory 22, the stimulus value calculation unit 23, the ROM 24, the chromaticity coordinate calculation unit 25, the acquisition unit 26, the color temperature calculation unit 27, the white balance control unit 28, and the chromaticity coordinate / color temperature information memory 29 are configured.

The control circuit 14 is a one-chip microcomputer that controls each part of the digital camera 1.
The imaging lens 2 includes a focus lens 2a, a zoom lens 2b, and the like configured from a plurality of lens groups. A driving circuit 3 is connected to the imaging lens 2, and the driving circuit 3 moves the focus lens 2 a and the zoom lens 2 b in the optical axis direction in accordance with a control signal sent from the control circuit 14.

Further, the drive circuit 3 operates the diaphragm / shutter in accordance with the control signal sent from the control circuit 14, that is, adjusts the diaphragm and the shutter speed to control the amount of light incident through the imaging lens. Control.
The diaphragm refers to a mechanism that limits the amount of light incident from the imaging lens 2, and the shutter speed refers to a mechanism that limits the amount of light applied to the CCD 7 over time.

The CCD 7 is scan-driven by the vertical driver 5 and TG 6, photoelectrically converts the intensity of light of each color of RGB values of the subject image formed at regular intervals, and outputs it to the sample hold circuit 8.
The sample hold circuit 8 samples the analog signal sent from the CCD 7 at a frequency suitable for the resolution of the CCD 7 (for example, correlated double sampling) and outputs the sampled signal to the analog-digital converter 9. Note that automatic gain adjustment (AGC) may be performed after sampling.
The analog-digital conversion circuit 9 converts the sampled analog signal into a digital signal and outputs the digital signal to the color separation circuit 10.

The color separation circuit 10 separates the RGB data, and outputs the R component data to the gain adjustment unit 11r, the G component data to the gain adjustment unit 11g, and the B component data to the gain adjustment unit 11b.
The gain adjustment unit 11 adjusts the respective gains of the R, G, and B data sent from the color separation circuit in accordance with the control signal sent from the white balance control unit 28, and performs image signal processing. To the unit 12.
The image signal processing unit performs color process processing including pixel interpolation processing, γ correction processing, and the like, and generates a luminance / color difference multiplexed signal (hereinafter referred to as a YUV signal) from RGB data.

  The memory 13 includes DRAM, ROM, and flash memory. The DRAM is used as a buffer memory for temporarily storing digitized subject image data after being imaged by the CCD 7 and also used as a working memory for the control circuit 14. The ROM is used for controlling the control circuit 14. Necessary data, programs, etc. are stored. The flash memory is an image memory that records captured image data.

The display unit 15 includes a color LCD and its driving circuit, and displays a subject imaged by the CCD 2 as a through image when in a shooting standby state, and displays a recorded image read from the flash memory and expanded when the recorded image is reproduced. indicate. In addition, chromaticity coordinates, a spectral distribution characteristic graph, a diagram showing a black body radiation locus, and the like are displayed. The display unit 15 corresponds to display means of the present invention.
The key input unit 16 includes a plurality of operation keys such as a shutter button, a bracket shooting button, an execution key, a cancel key, a cursor key, and a mode key, and outputs an operation signal corresponding to the user's key operation to the control circuit 14. The key input unit 16 corresponds to a specifying unit and a correction interval input unit of the present invention.

The prism diffraction grating 17 splits the incident light for each wavelength band and enters the sensor array 18. This prism diffraction grating 17 corresponds to the spectroscopic means of the present invention.
The sensor array 18 is driven by a driver / amplifier 19, photoelectrically converts the light separated for each incident wavelength band, and outputs the light to the driver / amplifier 19. This sensor array 18 functions as a photometric sensor array of the present invention.
The driver amplifier 19 amplifies the photoelectrically converted analog signal for each wavelength and outputs it to the analog-digital converter 20.
The analog-to-digital converter 20 digitally converts the input analog signal to acquire a spectral energy distribution L (λi), and stores the acquired spectral energy distribution table data in the energy distribution table memory.

The ROM 24 records color matching functions (λi), (λi), and (λi) of the RGB color system.
The stimulus value calculator 23 reads the color matching functions (λi), (λi), (λi) recorded in the ROM 24 and the spectral energy distribution L (λi) stored in the energy distribution table memory (spectral acquisition means). ), Multiplying the read color matching function by the spectral energy distribution L (λi), and summing the multiplication results for each wavelength (λi) over the entire n bands (i = 0 to n−1) of the wavelength region. Tristimulus values R, G, and B are calculated (stimulus calculation means).

Specifically, the tristimulus values R, G, and B can be obtained according to Equation 1 or Equation 2. Equation 2 is an equation when n → ∞ in Equation 1. However, the integration (∫ _VIS ) is taken in the visible wavelength region.

  Then, the stimulus value calculation unit 23 converts the calculated tristimulus values R, G, and B into tristimulus values X, Y, and Z in the XYZ color system. This conversion is performed according to Equation 3. Note that the color matching functions (λi), (λi), and (λi) based on the XYZ color system may be recorded in the ROM 24 in advance, and the tristimulus values XYZ may be directly obtained.

When the stimulation value calculation unit 23 calculates the tristimulus values X, Y, and Z of the XYZ color system, the stimulation value calculation unit 23 outputs the calculated tristimulus values X, Y, and Z to the chromaticity coordinate calculation unit 25.
The chromaticity coordinate calculation unit 25 obtains chromaticity coordinates (x, y, z) from the input tristimulus values according to Equation 4. This function corresponds to the coordinate calculation means of the present invention.

After calculating the chromaticity coordinates (x, y, z), the chromaticity coordinate calculation unit 25 outputs the calculated chromaticity coordinate values to the color temperature calculation unit 27. Further, the calculated chromaticity coordinate value is stored in the chromaticity coordinate / color temperature information memory 29.
The color temperature calculation unit 27 obtains a color temperature Ta, a deviation Δuv from the black body radiation locus, and the like from the input chromaticity coordinates (color temperature calculation means). Here, the color temperature Ta used for the white balance control is a correlated color temperature (unit: K) corresponding to the chromaticity coordinates of the black body radiation locus, with the relationship between the temperature and the wavelength when the black body is radiated as an index. , Kelvin).

A method for calculating the color temperature Ta from the chromaticity coordinates will be described.
First, according to Planck's radiation law, the radiant energy spectrum e (λ, T) of blackbody radiation can be obtained by Equation 5, and by using this number, the wavelength of blackbody radiation at each temperature is calculated. The spectral energy for each can be determined.
Where λ is the wavelength of light, T is the absolute temperature of the radiator, h is the Planck's constant, k is the Boltzmann constant, and c is the speed of light in vacuum.

Then, as described above, the result obtained by multiplying the spectral energy for each wavelength by the color matching function of the wavelength is totaled (added) over the entire visible light region to obtain tristimulus values, and the chromaticity coordinates Is obtained. According to this method, the chromaticity coordinates equivalent to the color temperature Ta can be obtained, and the color temperature Ta can be obtained from the chromaticity coordinates by performing a reverse calculation.
Also, as shown in FIG. 2, a conversion table of chromaticity coordinates (x, y, z) and color temperature Ta is recorded in advance in the color temperature calculation unit 27, and the chromaticity coordinates are converted using this conversion table. The corresponding color temperature Ta may be obtained.
Here, the obtained color temperature Ta is set to 6500 K, and the method of obtaining the deviation Δuv is a well-known technique, so the description thereof is omitted here.

When the color temperature calculation unit 27 obtains the color temperature Ta, it outputs the value of the color temperature Ta to the white balance control unit 28, and stores the color temperature Ta and the deviation Δuv in the chromaticity coordinate / color temperature information memory 29. Remember me.
The control circuit 14 determines whether or not the deviation Δuv stored in the chromaticity coordinate / color temperature information memory 29 is smaller than the threshold value recorded in the ROM 24. A control signal for performing white balance control is sent to the balance control unit 28.
On the other hand, if the control circuit 14 determines that the deviation Δuv is larger than the threshold value recorded in the ROM 24, it determines that the deviation is outside the allowable range, and performs error processing for color temperature measurement.

When receiving a control signal for white balance control from the control circuit 14, the white balance control unit 28 performs white balance by controlling the gain adjusting unit 11 (white balance control means). There are various methods for performing the white balance. To control the white balance based on a more precise measurement value of the color temperature Ta, the color temperature Ta obtained from the characteristic data of the color temperature Ta and the relative intensity of the RGB components. The white balance is obtained by obtaining the gain control amount of the RGB signal corresponding to the above from the reciprocal of the relative intensity and controlling the gain adjusting unit 11.
FIG. 3 shows the relative intensities of the color temperature Ta and the RGB components (when 5000K is used as a reference). As shown in the figure, the current color temperature Ta is 6500K, and it can be seen that the relative intensities of the RGB components are 1.14, 1.00, and 0.76.

FIG. 4 shows a state in which the gain adjusting unit 11 is controlled so that the color temperature 6500K becomes the color temperature 5000K.
When the color temperature calculation unit 27 outputs the detected color temperature 6500K to the white balance control unit 28, the white balance control unit 28 reciprocates the relative intensity of each of the R component, the G component, and the B component (R component; 1 / The gain adjustment units 11r, 11g, and 11b are controlled so that the gain control amount corresponds to 0.76, G component; 1, B component; 1 / 1.14).
The RGB components picked up by the CCD 7 are separated into an R component, a G component, and a B component by the color separation circuit 10, and the R component is amplified to 1 / 0.76 times by the gain adjusting unit 11r, and the G component is gain. The adjustment unit 11g amplifies the signal by a factor of 1, the gain adjustment unit 11b amplifies the signal by a factor of 1 / 1.14, and each RGB component is sent to the image signal processing unit 12.
Note that white balance may be performed based on the obtained chromaticity coordinates.

B. Operation of Digital Camera 1 The operation of the digital camera 1 in the first embodiment will be described with reference to the flowchart of FIG.
Photometric processing is performed (step S1), the light separated by the wavelength by the prism diffraction grating 17 is converted into a digital signal by the analog / digital converter 20 by converting the analog signal received by the sensor array 18 and the driver / amplifier 19; The spectral energy distribution L (λi) of the light source light is acquired, and the acquired table data of the spectral energy distribution of the light source light is stored in the energy distribution table memory 21 (step S2).
Here, FIG. 6A shows an example of the spectral energy distribution L (λi) for each wavelength incident on the sensor array 19 or the like via the prism diffraction grating 18, and FIG. 2 shows an example of a spectral energy distribution table stored in the energy distribution table memory.

  When the spectral energy distribution table L (λi) for each wavelength is acquired, the acquired spectral energy distribution L (λi) and the color matching functions (λi), (λi), (λi) of the RGB color system recorded in the ROM 24 are obtained. Tristimulus values R, G, and B are calculated from λi) (step S3). This calculation is performed by multiplying the color matching functions (λi), (λi), (λi) by the spectral energy distribution L (λi) stored in the energy distribution table memory, and multiplying the result of each wavelength (λi). Tristimulus values R, G, and B are calculated by summing up all n bands (i = 0 to n−1) in the wavelength region.

Specifically, tristimulus values R, G, and B can be calculated according to Equation 1 or Equation 2.
FIG. 7C shows the color matching functions (λi), (λi), and (λi) of the RGB color system. The ROM 24 stores the color matching function table as shown in FIG. Data is recorded.

Next, when the tristimulus values RGB are calculated, the tristimulus values R, G, and B of the RGB color system are converted into the tristimulus values X, Y, and Z of the XYZ color system (step S4). This conversion can be performed according to Equation 3.
Note that the XYZ color system color matching functions (λi), (λi), and (λi) are recorded in advance in the ROM 24, and the spectral energy distribution L (λi) and the XYZ color system color matching function (λi) are recorded. , (Λi), (λi) may be used to directly calculate the tristimulus values X, Y, Z of the XYZ color system.
FIG. 8E shows the color matching functions (λi), (λi), and (λi) of the XYZ color system, and the ROM 24 stores the color matching function table shown in FIG. Record the data.

Next, chromaticity coordinates (x, y, z) are calculated from the calculated tristimulus values X, Y, Z according to Equation 4 (step S5).
Next, the deviation Δuv from the color temperature Ta and the black body radiation locus is calculated from the chromaticity coordinates (x, y, z) (step S6). As a calculation method, the spectral energy for each wavelength at each temperature of black body radiation is obtained according to the above-mentioned Planck's radiation law, and the result obtained by multiplying the spectral energy for each wavelength by the color matching function for each wavelength is visible. The color corresponding to the chromaticity coordinates is calculated by back-calculating the method of calculating the chromaticity coordinates corresponding to the color temperature by calculating the chromaticity coordinates after obtaining the total (addition) over the entire light region. The temperature Ta can be calculated. Here, the obtained color temperature Ta is 6500K (Kelvin). The unit of color temperature may be other units such as MIRED and LB index.
Further, a color temperature and chromaticity coordinate conversion table as shown in FIG. 2 is recorded in advance in the color temperature calculation unit 27, so that the color temperature and chromaticity coordinate conversion table is used to convert the color temperature and chromaticity coordinate from the chromaticity coordinate to the color. The temperature Ta may be obtained.
Since the method for calculating the deviation Δuv is a well-known technique, the description thereof is omitted here.

Next, it is determined whether or not the obtained deviation Δuv is within an allowable range (step S7). In this determination, it is determined whether or not it is smaller than a threshold value recorded in advance in the ROM 24. If it is smaller, it is determined to be within the allowable range, and if it is larger, it is determined to be outside the allowable range.
If it is determined that it is out of the allowable range, an error display for notifying that the measurement of the color temperature has failed is performed.

On the other hand, if it is determined that it is within the allowable range, the white balance of the imaging signal is controlled based on the color temperature and chromaticity coordinates (step S8).
There are various methods for controlling the white balance, but in order to control the white balance based on a more precise measurement value of the color temperature Ta, the color temperature obtained from the characteristic data of the color temperature Ta and the relative intensity of the RGB components. White balance is performed by obtaining the gain control amount of the RGB signal corresponding to Ta from the reciprocal of the relative intensity and controlling the gain adjusting unit 11.

As described above, in the first embodiment, a spectrophotometer for measuring the spectral distribution characteristics of the light source is provided, and tristimulus values are calculated from the spectral distribution of the energy amount of the light source light and the color matching function. Since the chromaticity coordinates are calculated from the calculated tristimulus values and the color temperature is obtained from the calculated chromaticity coordinates, precise WB can be performed based on the highly accurate color temperature.
In addition, it is not necessary to separately provide an identification unit, a color temperature detection unit, and the like for each light source, and even when various light sources such as a three-wavelength fluorescent lamp or a plurality of light sources are mixed, it is possible to cope with them.
Also, since white balance is obtained by obtaining chromaticity coordinates and color temperature, even with a light source such as a fluorescent lamp, WB settings and WB specified by specific color temperature units such as Kelvin, MIRED, and LB index, and chromaticity coordinates Bracketing photography is also possible.

In the first embodiment, the chromaticity coordinates are calculated from the tristimulus values XYZ of the XYZ color system. However, without obtaining the tristimulus values XYZ of the XYZ color system, the RGB table is used as it is. You may make it obtain | require a chromaticity coordinate from tristimulus value RGB of a color system.
In addition, instead of the color matching function based on the photosensitivity characteristics in photopic vision, the color matching function is set based on the characteristics of the dark vision and the visual acuity characteristics of the visually impaired. You may make it calculate a coordinate and color temperature.

[Second Embodiment]
Next, a second embodiment will be described.
In the second embodiment, skin color balance control is performed so that the skin color of the imaged subject becomes the user's favorite skin color.

C. Configuration of Digital Camera 1 The second embodiment also implements the imaging apparatus of the present invention by using a digital camera 1 having a configuration similar to that shown in FIG.
However, the function of the configuration is different in the following points.

First, the ROM 24 further records a plurality of data of spectral reflectance characteristics R2 (λi) of the subject (skin color here) as shown in FIG.
When the control circuit 14 performs white balance of the image data captured by the white balance control unit 28 as shown in the first embodiment, the image of the image data with the white balance (through image of the subject) is displayed. It is displayed on the display unit 15 (display control means).

At this time, the user operates the key input unit 16 while viewing the through image of the subject displayed on the display unit 15 to operate the focus frame, the photometry frame, etc. Specify a partial area (face, arm, etc.).
The control circuit 14 determines whether or not a partial area of the subject image specified by the user has been specified, and if it is determined that it has been specified, specifies the specified partial area as the specified area. The determination as to whether or not the partial area has been designated is made based on whether or not an operation signal for designating the partial area has been sent from the key input unit 16.
Further, when a partial area is designated (designated area is designated), the control circuit 14 specifies spectral reflectance characteristics R2 (λi) (color information) of a plurality of subjects recorded in the ROM 24. A list display is displayed on the display unit 15.

At this time, the user operates the key input unit 16 so that the partial region designated from the list display of the spectral reflectance characteristic R2 (λi) displayed on the display unit 15 becomes his / her favorite skin color. Spectral reflectance characteristic R2 (λi) is selected.
The list of spectral reflectance characteristics R2 (λi) is not displayed on the display unit 15. For example, the display unit 16 displays a palette in which a plurality of chromaticities and color samples close to skin color are arranged. A chromaticity or color sample is selected from the displayed palette, and the color temperature (color information) or spectral reflectance characteristic R2 (λi) (color information) corresponding to the selected chromaticity or color sample is selected. May be selected automatically.

The control circuit 14 determines whether or not the spectral reflectance characteristic R2 (λi) has been selected by the user. If the control circuit 14 determines that the spectral reflectance characteristic R2 (λi) has been selected, the control circuit 14 sets the selected spectral reflectance characteristic R2 as color information (setting means). ), A control signal indicating that the set color information, that is, the spectral reflectance characteristic R 2 (λi) is acquired from the ROM 24 is sent to the stimulus value calculation unit 23.
When an operation signal for acquiring the spectral reflectance characteristic R2 (λi) set from the control circuit 14 is sent from the control circuit 14, the stimulus value calculation unit 23 receives the selected spectral reflectance characteristic R2 (λi) from the ROM 24. Get the.

  Then, the stimulus value calculation unit 23 reflects the light source light to the subject from the spectral energy distribution L1 (λi) of the light source light stored in the energy distribution table memory 21 and the acquired spectral reflectance characteristic R2 (λi). Then, a simulation calculation of the spectral energy distribution L2 (λi) of the light incident on the imaging system (imaging lens 2, CCD 7, etc.) is performed (calculation means). The simulation calculation of the spectral energy distribution L2 (λi) can be obtained by Equation 6.

Then, the stimulus value calculator 23 calculates tristimulus values from the calculated spectral energy distribution L2 (λi) and the color matching function recorded in the ROM 24, and calculates the determined tristimulus values as chromaticity coordinates. To the unit 25.
The chromaticity coordinate calculation unit 25 calculates chromaticity coordinates (x2, y2, z2) from the input tristimulus values (corrected coordinate calculation means), and uses the calculated chromaticity coordinates (x2, y2, z2). Output to the color temperature calculation unit 27. The calculated chromaticity coordinates (x2, y2, z2) are stored in the chromaticity coordinate / color temperature information memory 29.

The color temperature calculation unit 27 calculates the color temperature Ta2 from the input chromaticity coordinates (x2, y2, z2) (corrected color temperature calculation means) and stores it in the chromaticity coordinate / color temperature information memory 29.
In addition, the control circuit 14 acquires an RGB component corresponding to the designated area among the RGB components output from the gain adjustment units 11r, 11g, and 11b, and obtains a spectral energy distribution L3 (λi) from the acquired RGB component. (Calculation means). Then, the obtained spectral energy distribution L3 (λi) is output to the stimulus value calculator 23.
From the spectral energy distribution L3 (λi) input to the stimulus value calculator 23, the chromaticity coordinates (x3, y3) of the designated area are passed through the stimulus value calculator 23, the chromaticity coordinate calculator 25, and the color temperature calculator 27. , Z3) (correction coordinate calculation means) and color temperature Ta3 (correction color temperature calculation means). Further, the obtained chromaticity coordinates (x3, y3, z3) and the color temperature Ta3 are stored in the chromaticity coordinate / color temperature information memory 29.

The control circuit 14 stores the chromaticity coordinates (x3, y3, z3) of the designated area stored in the chromaticity coordinate / color temperature information memory 29 and the chromaticity coordinates (x2) of L2 (λi) obtained by the simulation calculation. , Y2, z3), or a control signal is sent to the white balance control unit so that the color temperature Ta3 of the designated area substantially matches the color temperature Ta2 of L2 (λi) obtained by the simulation calculation.
Note that a control signal may be sent to the white balance control unit 28 so that the spectral energy distribution L3 (λi) of the designated area substantially matches L2 (λi) obtained by the simulation calculation.

Then, the white balance processing is performed by adjusting the gain of the entire RGB component by adjusting the gain adjusting unit 11 according to the control signal sent to the white balance control 28 (white balance control means).
Then, the control circuit 14 re-acquires each component of the partial region designated by the user among the RGB components of the imaging signals output from the gain adjusting units 11r, 11g, and 11b, and the spectral energy distribution L ′ thereof. 3 (λi) is obtained, the spectral energy distribution L3 ′ (λi) is output to the stimulus value calculator 23, calculated via the stimulus value calculator 23, the chromaticity coordinate calculator 25, and the color temperature calculator 29, The chromaticity coordinates (x3 ′, y3 ′, z3 ′) and the color temperature Ta3 ′ stored in the chromaticity coordinate / color temperature information memory 29 are displayed on the display unit 15 together with the through image of the subject (display control means).

D. Operation of Digital Camera 1 The operation of the digital camera 1 in the second embodiment will be described with reference to the flowcharts of FIGS.
A photometric process is performed (step S21), and the light separated by the wavelength by the prism diffraction grating 17 is converted into a digital signal from the analog signal received by the sensor array 18, the driver amplifier 19, and the analog-digital converter 20. The spectral energy distribution L1 (λi) of the light source light is acquired, and the acquired table data of the spectral energy distribution of the light source light is stored in the energy distribution table memory 21 (step S22).

Next, the tristimulus value is calculated from the spectral energy distribution L1 (λi) of the light source light stored in the energy distribution table memory 21 and the color matching function recorded in the ROM 24, and the chromaticity coordinates ( Calculation of x1, y1, z1), and calculation of the color temperature Ta from the calculated chromaticity coordinates (x1, y1, z1) (step S23).
Next, white balance processing is performed by controlling the gain adjusting unit 11 based on the calculated color temperature Ta (step S24).
The operations up to here are the same as those in the first embodiment.

Next, when white balance processing is performed, a through image of the subject imaged by the CCD 7 after white balance processing is displayed on the display unit 15 (step S25).
Next, a part of the subject image designated by the user is designated as a designated area (step S26).
Here, the user operates the key input unit 16 while viewing the through image of the subject to operate the focus frame, the photometry frame, etc. Etc.). The partial area specified by the user may be directly specified by a touch panel or the like, or may be specified by operating a cursor.

Next, a plurality of spectral reflectance characteristics R2 (λi) recorded in the ROM 24 are displayed as a list on the display unit 15, and the spectral reflectance characteristics R2 (λi) selected by the user are acquired from the ROM 24 (step S27).
Here, when the user operates the key input unit 16, the skin color of the specified partial area from the list display of the spectral reflectance characteristics R2 (λi) displayed on the display unit 15 is his / her favorite skin color. Spectral reflectance characteristic R2 (λi) is selected such that The list of spectral reflectance characteristics R2 (λi) is not displayed on the display unit 15. For example, the display unit 16 displays a palette in which a plurality of chromaticities and color samples close to skin color are arranged. A chromaticity or color sample is selected from the displayed palette, and a spectral reflectance characteristic R2 (λi) corresponding to the color temperature or spectral distribution characteristic corresponding to the selected chromaticity or color sample is acquired. You may do it.

  Next, the light source light is reflected by the subject from the spectral energy distribution L1 (λi) of the light source light acquired in step S22 and the spectral reflectance characteristic R2 (λi) acquired in step S27, and the imaging system (imaging lens, CCD 7). Etc.) and a simulation calculation of the spectral energy distribution L2 (λi) of the light incident on it (step S28). The simulation calculation of the spectral energy distribution L2 (λi) can be obtained by Equation 6.

Next, tristimulus values are calculated from the spectral energy distribution L2 (λi) obtained by the simulation calculation and the color matching function, chromaticity coordinates (x2, y2, z2) are calculated from the calculated tristimulus values, and the calculated color The color temperature Ta2 is calculated from the degree coordinates (x2, y2, z2), and the calculated chromaticity coordinates (x2, y2, z2) and the color temperature Ta2 are stored in the chromaticity coordinate / color temperature information memory 29 (step) S29).
Next, in step S30, RGB components of the imaging signal in the designated area specified (part of the subject image designated by the user) are acquired.

  Next, a spectral energy distribution L3 (λi) is obtained from the RGB components of the acquired imaging signal of the designated area, and tristimulus values and chromaticity coordinates (x3, y3, z3) are obtained from the obtained spectral energy distribution L3 (λi). The color temperature Ta3 is calculated, and the calculated chromaticity coordinates (x3, y3, z3) and the color temperature Ta3 are stored in the chromaticity coordinate / color temperature information memory 29 (step S31).

Next, the chromaticity coordinates (x3, y3, z3) of the designated area recorded in the chromaticity coordinate / color temperature information memory 29 are obtained as the chromaticity coordinates (x2, y2, z3), a control signal is sent to the white balance control unit so that the spectral energy distribution L3 (λi) of the designated area substantially matches the spectral energy distribution L2 (λi) obtained by the simulation calculation, The white balance control unit 28 controls the gain adjustment unit 11 in accordance with the control signal to adjust the gain of the entire RGB component and perform white balance processing (step S32).
Note that the white balance processing may be performed so that the color temperature Ta3 of the designated area substantially matches the color temperature Ta2 of the spectral energy distribution L2 (λi) obtained by the simulation calculation.

Next, among the RGB components of the imaging signal output from the gain adjustment unit 11, the RGB of a partial region designated by the user is obtained again, and the spectral energy distribution L3 ′ (λi) is obtained. The degree coordinates (x3 ′, y3 ′, z3 ′) and the color temperature Ta3 ′ are calculated again (step S33).
Next, a chromaticity diagram is displayed on the display unit 15 together with the through image of the subject, and the calculated chromaticity coordinates (x3 ′, y3 ′, z3 ′) and color temperature Ta3 ′ of the designated area are displayed on the chromaticity diagram. It is displayed (step S34).

FIG. 12 shows an example of chromaticity coordinates displayed together with a through image of a subject. Here, the color temperature Ta is not displayed.
As can be seen from the figure, a chromaticity diagram is displayed together with a through image of the subject (female face). On the chromaticity diagram, a thick line 100 parallel to the Y axis and a thick line 110 parallel to the X axis are displayed. The intersection of the bold line 100 and the bold line 110 indicates the chromaticity coordinates (x3 ′, y3 ′) calculated in step S34. In the chromaticity diagram, only x and y of the chromaticity coordinates x, y and z are displayed. This is because the chromaticity coordinates x, y, and z have a relationship of x + y + z = 1, so that if x and y are known, z is inevitably known. A frame 120 is a focus frame or a photometric frame for designating a partial area.

  Note that the positions of the thick line 100 and the thick line 110 on the chromaticity diagram may be changed by the user's operation of the key input unit 16 (the thick line 100 and the thick line 110 function as a coordinate cursor). Thus, by recognizing the current chromaticity coordinates and changing the chromaticity coordinates, it is possible to finely adjust the skin color balance so that the color of the specified partial region becomes a favorite skin color. That is, the white balance processing is performed so that the changed chromaticity coordinates (color information) and the chromaticity coordinates obtained from the spectral energy distribution L3 (λi) of the imaging signal in the designated area substantially coincide. Thereby, the spectral energy distribution L2 (λi) is obtained from the spectral reflectance characteristic R2 (λi) and the spectral energy distribution L1 (λ) of the light source light, and further, the chromaticity coordinates are obtained from the spectral energy distribution L2 (λi). It is not necessary to do this.

As described above, in the second embodiment, the light source light reflected from the subject and incident on the imaging system is obtained from the spectral reflectance characteristic that gives the desired skin color and the spectral energy distribution characteristic of the light source light. Since the spectral energy distribution characteristics are simulated and white balance processing is performed, the color tone of the entire image can be reduced without extracting only the face or skin color part or forcibly color-converting only the skin area as in the past. Are corrected together, so that only the face and skin color are not lifted, the image quality is different, and the color tone does not become strange, so that a natural image can be obtained.
Further, since the process is simple, the skin color balance can be performed at high speed.
Further, the skin color balance can be performed so that the user's favorite skin color is obtained.

In the second embodiment, the skin color balance has been described. However, the present invention is not limited to this, and color balance may be performed.
That is, the spectral reflectance characteristic data corresponding to each chromaticity is recorded in the ROM 24, and the user selects the spectral reflectance characteristic such that the color of the specified partial region becomes the user's favorite color. Based on the selected spectral reflectance characteristic and the spectral energy distribution of the light source light, the spectral energy distribution of the light incident on the imaging system after the light source light is reflected by the subject may be simulated to perform white balance processing. Good.

  Before performing skin color balance and color balance, a chromaticity diagram as shown in FIG. 12 is displayed together with a through image of the subject, and the user operates the thick line 100 and the thick line 110 on the chromaticity diagram. By setting chromaticity coordinates, it may be possible to perform skin color balance and color balance.

The chromaticity diagram to be displayed together with the through image of the subject includes the chromaticity diagram of the RGB color system, the chromaticity diagram of the XYZ color system, the UV chromaticity diagram of the UVW color system (CIE1960), U ^* V ^* W ^* Uniform color space (CIE1964), CIELAB's L ^* A ^* B ^* Uniform color space, Munsell color system, and other chromaticity coordinates, chromaticity diagram, chromaticity space coordinates, etc. May be displayed.
FIG. 13G shows an example when the Munsell color system is displayed instead of the XYZ color system, and FIG. 13H shows an example when the CIELAB uniform color space is shown. It is.

Further, as shown in FIGS. 14 and 15, the skin color balance control circuit may be configured using color temperature detection of an external photometry method using an RGB sensor or a CCD internal photometry method.
In this case, based on the measured chromaticity coordinates and color temperature of the light source light, the R, G, B signals are obtained from the captured image data after WB adjustment based on the data of a partial area designated by the focus frame or the like. 3 is obtained, the color temperature is obtained by referring to the color temperature and RGB component relative intensity characteristic data as shown in FIG. 3 and a conversion table, and the color temperature and the chromaticity coordinate comparison table of FIG. The degree coordinate may be obtained. Alternatively, the tristimulus values may be directly calculated from the RGB of the imaging signal, and the chromaticity coordinates may be obtained from the stimulus values.

[Third Embodiment]
Next, a third embodiment will be described.
In the third embodiment, flesh-color bracket shooting and CB (color balance) bracket shooting are performed according to shooting conditions set by the user.

E. Configuration of Digital Camera 1 The third embodiment also implements the photographing apparatus of the present invention by using the digital camera 1 having the same configuration as that shown in FIG.
First, a function of a characteristic configuration in the digital camera 1 according to the third embodiment will be described.

The control circuit 14 is set to the setting mode by the user's operation of the key input unit 16, and when the correction interval, the correction order, and the number of corrections, which are the shooting conditions for bracket shooting, are input, the shooting of the input bracket shooting is performed. Set the conditions.
Here, the correction interval refers to an interval at which bracketing is performed in flesh color bracket photography and CB bracket photography. For example, when bracketing shooting is performed by bracketing chromaticity coordinates (x, y), the correction interval is (Δx, Δy).

The correction order includes an upward direction (+ direction), a downward direction (− direction), 0 + − order, 0− + order, and the like. For example, if 0 is the initial depth-of-field condition without correction, in the upward direction (+ direction), → (−2 correction interval) → (−1 correction interval) → (0, no correction) ) → (+1 correction interval) → (+2 correction interval) → ······· In the case of the down direction (− direction), → (+2 correction interval) → (+1 correction interval) → (0, no correction) ) → (−1 correction interval) → (−2 correction interval) →.
In the case of 0 + −order, (0, no correction) → (+1 correction interval) → (+2 correction interval) →... (−1 correction interval) → (−2 correction interval) →. In the case of 0- + order, (0, no correction)-> (-1 correction interval)-> (-2 correction interval)->-> (+1 correction interval)-> (+2 correction interval)->- It becomes.
The number of corrections refers to the number of times of continuous shooting at a time by bracket shooting.

For example, when the chromaticity coordinates of the currently designated partial area are (x, y), the correction interval (Δx, Δy), the correction order (upward order), and the number of corrections (5) are set by the user. In this case, the first image to be bracketed is obtained by controlling the gain adjusting unit 11 so that the chromaticity coordinates of the specified partial area become (x−2Δx, y−2Δy). Take a picture with balance. Then, the second image is photographed by performing white balance by controlling the gain adjusting unit 11 so that the chromaticity coordinates of the specified partial region become (x−Δx, y−Δy). . Similarly, the chromaticity coordinates of the specified partial area are (x, y) for the third image, and the chromaticity coordinates of the specified partial area are (x + Δx, y + Δy) for the fourth image. The gain adjustment unit 11 is controlled such that the chromaticity coordinates of the partial area thus obtained are (x + 2Δx, y + 2Δy), thereby performing white balance and performing continuous shooting of the subject.
The function of continuously shooting the subject by bracket shooting corresponds to the continuous shooting control means of the present invention.

F. Operation of Digital Camera 1 The operation of the digital camera 1 in the third embodiment will be described with reference to the flowcharts of FIGS. Since the operation of skin color balance bracket shooting and color balance bracket shooting are almost the same, here, processing of color balance bracket shooting will be described.

When the mode is set by the user's operation of the key input unit 16, it is determined whether or not the set mode is the shooting mode (step S51).
If it is not the shooting mode, it is determined whether or not the currently set mode is the setting mode (step S52).

If it is not the setting mode, other mode processing is performed, and if it is the setting mode, it is determined whether or not the CB bracket setting is set (step S53).
When the CB bracket setting is not set, other setting processing is performed. When the CB bracket setting is set, the correction interval (Δx, Δy) and the correction order of the chromaticity coordinates which are shooting conditions for bracket shooting input by the user. Then, the correction number i (i = 2k + 1) is set (step S54), and the process returns to step S51. Here, it is assumed that the correction interval (Δx = 0.01, Δy = 0.01), the correction order is ascending order, and the correction number i is set to three. Further, since the number i of correction is i (i = 2k + 1 = 3), k = 1.

If it is determined in step S51 that the currently set mode is the shooting mode (branch to Y in step S51), shooting conditions such as exposure conditions are set (step S55), and photometric processing is performed (step S56).
Then, chromaticity coordinates and color temperature are obtained from the spectral energy distribution L (λ) of the light source stored in the energy distribution table memory 21 (step S57). The calculation method of the chromaticity coordinates and the color temperature is as described in the first embodiment.
Then, white balance processing is performed based on the calculated color temperature (step S58).

Then, zoom processing, AF processing, and the like are performed (step S59), and shooting information such as shooting conditions is displayed on the display unit 15 together with the through image (step S60). The shooting information refers to the current color temperature, chromaticity coordinates, chromaticity diagram, etc., in addition to general shooting conditions such as aperture value and shutter speed.
Then, it is determined whether or not to shoot the subject currently being picked up (step S61). This determination is made based on whether or not an operation signal corresponding to the operation of the shutter button or the operation of the bracket shooting button is sent from the key input unit 16.
If it is determined not to shoot (branch to NO in step S61), the process proceeds to step S74 to perform other key processing, display processing, and the like.

On the other hand, if it is determined that shooting is to be performed (branch to Y in step S61), it is determined whether or not CB bracket shooting is being performed (step S62).
This determination is made based on whether or not an operation signal corresponding to the operation of the bracket shooting button is sent from the key input unit 16. Although a shutter button for shooting still images and a bracketing shooting button are provided separately, the user may instruct to perform bracketing shooting in advance, and bracketing shooting may be performed when the shutter button is pressed. Good.

  If it is determined that the shooting is not CB bracket shooting, other shooting processing is performed. If it is determined that the shooting is CB bracket shooting, the chromaticity coordinates (x0, y0, z0) and the color temperature Ta are calculated (step S63). As described in the second embodiment, this calculation is performed using the RGB components of the imaging signal of the partial area designated by the user, that is, among the RGB components output from the gain adjusting units 11r, 11g, and 11b. Chromaticity coordinates and color temperature are obtained from the RGB components of a partial area designated by the user. Here, it is assumed that the obtained chromaticity coordinates are, for example, (x0, y0) = (0.1, 0.3).

Next, it is determined whether the correction order of the shooting conditions for bracket shooting set by the user is an ascending order (step S64).
Here, since the correction order is set to the ascending order in step S54, the initial values (x1, y1) of the chromaticity coordinates of the CB in the ascending order are set (step S65).
Here, the initial value (x1, y1) in the ascending order is (x1 = x0−k · Δx, y1 = y0−k · Δy).
Therefore, the initial values (x1 = 0.09, y1 = 0.29) are used here. However, (x0, y0) = (0.1, 0.3), (Δx, Δy) = (0.01, 0.01), and k = 1.
Next, the shooting order m is set as “m = + 1” (step S66), and the process proceeds to step S70.

On the other hand, if it is not the ascending order in step S64, it is determined whether or not the correction order is the descending order (step S67).
If it is in descending order, the initial value (x1, y1) of the chromaticity coordinates of the CB in descending order is set (step S68).
Here, the initial value (x1, y1) in the descending order is (x1 = x0 + k · Δx, y1 = y0 + k · Δy).
Therefore, in this case, the initial values (x1 = 0.11, y1 = 0.31) are obtained.
Next, the photographing order m is set to “m = −1” (step S69), and the process proceeds to step S70.

In step S70, the number of shots n is set to “n = 2k + 1”, and the number of shots j is set to “j = 0”. Here, k = 1 (since it is set as the number of corrections i (i = 2k + 1 = 3) in step S54), the number of shots n is “n = 2 · 1 + 1 = 3”.
Next, CB correction photographing processing is performed (step S71). Here, the operation of the CB correction photographing process will be described with reference to the flowchart of FIG.

When the CB correction shooting process is started, the process proceeds to step S91 in FIG. 19, and the correction chromaticity coordinates (x, y) to be shot by CB bracket shooting are set. The set correction chromaticity coordinates are (x = x1 + m · j · Δx, y = y1 + m · j · Δy).
Therefore, here, since the correction order is set as an ascending order, (x1 = 0.09, y1 = 0.29), and therefore, correction chromaticity coordinates (x = 0.09, y = 0.0). 29). However, “m = + 1”, “j = 0”, “Δx = 0.01, Δy = 0.01”.

Next, a color temperature Ta corresponding to the corrected chromaticity coordinates (x, y) is calculated (step S92), and a partial region designated based on the calculated color temperature Ta becomes the calculated color temperature Ta. Then, the gain adjustment unit 11 is controlled to adjust the gains of the entire RGB components and perform white balance processing (step S93). Note that the gain of the entire RGB component is adjusted by controlling the gain adjustment unit 11 so that the chromaticity coordinates (x0, y0) of the specified partial area become the corrected chromaticity coordinates (x, y). Thus, white balance processing may be performed.
Next, the subject is photographed under the set photographing conditions, the photographed image data is stored in the DRAM (step S94), and the image data stored in the DRAM is recorded in the flash memory (step S95).

When the image data is recorded in the flash memory, the process proceeds to step S72 in the flowchart of FIG. 17, and the photographed number j is set to “j = j + 1”. Here, since j = 0, the newly set number of shots j is “j = 1”.
Next, it is determined whether the number of shots j is equal to or greater than the number of shots n (step S73). Here, since j = 1 and n = 3, it is determined that the number of shots j is smaller than the number of shots n, and the process returns to step S71 to perform CB correction shooting processing.
That is, the corrected chromaticity coordinates (x, y) = (0.1, 0.3) are set in step S91 in FIG. 19, and the subject is subjected to white balance processing so that the set corrected chromaticity coordinates are obtained. Is recorded, and the captured image data is recorded in the flash memory (steps S92 to S95).

Then, the process proceeds to step S72 in FIG. 17, in which the number of shots j is set to “j = j + 1 = 1 + 1 = 2”, and whether the number of shots j (j = 2) is equal to or greater than the number of shots n (n = 3). Since j is smaller than n, the process returns to step S71. This operation is repeated until it is determined that the number of shots j is greater than or equal to the number of shots n.
As for the chromaticity coordinates (x, y) of the specified partial area of the image photographed by this loop (step S71 to step S73), the first image is (0.09, 0.29), and the second image is (0.1, 0.3) and the third one is (0.11, 0.31).

Further, in the descending order, the chromaticity coordinates (x, y) of the specified partial area of the image photographed by this loop are (0.11, 0.31) for the first image, Since the eyes are (0.1, 0.3) and the third is (0.09, 0.29), it can be seen that the order of photographing is reverse in the descending order and the ascending order.
If it is determined that the number of shots i is greater than or equal to the number of shots (branch to Y in step S73), other key processing and display processing are performed (step S74).

On the other hand, if it is determined in step S67 that the correction order is not descending, the process proceeds to step S75 in FIG. 18 to determine whether the correction order is 0 + -order.
If it is determined that the order is not 0 + −, the subject is photographed in another process, that is, in another correction order.
On the other hand, if it is determined that the order is 0 + −, the initial value of the CB chromaticity coordinates (x1, y1) is set to (x1 = x0, y1 = y0) (step S76). Therefore, the initial value (x1, y1) = (0.1, 0.3).

Next, the shooting order m is set to “m = + 1” (step S77), the shot number n is set to “n = k + 1”, and the shot number j is set to “j = 0” (step S78). Here, since k = 1, the number of shots n is set to “2”.
Next, the process proceeds to step S79, where CB correction photographing processing is performed.
As described above, the CB correction shooting process proceeds to step S91, and the correction chromaticity coordinates (x, y) of CB bracket shooting are set.
Here, since x = x1 + m · j · Δx and y = y1 + m · j · Δy, x = 0.1 + 1 × 0 × 0.01 = 0.1, y = 0.3 + 1 × 0 × 0.01 = 0. That means three.

Next, a color temperature Ta corresponding to the set chromaticity coordinates is calculated, a subject is photographed after white balance processing is performed based on the computed color temperature, and the photographed image data is recorded in a flash memory ( Step S92 to Step S95).
Next, the process proceeds to step S80 in FIG. 18, where j is set to “j = j + 1 = 0 + 1 = 1”, and it is determined whether or not the number of shots j (j = 1) is equal to or greater than the number of shots n (n = 2). (Step S81). Here, since j is smaller than n, the process proceeds to step S79 and the above operation is repeated.

As for the chromaticity coordinates (x, y) of a specified partial area of an image photographed by this loop, the first image is (0.1, 0.3) and the second image is (0.11, 0). .31).
When the second image is taken, the number of shots j is 2 (j = 1 + 1 = 2). In step S81, the number of shots j (j = 2) is the number of shots n (n = n). 2) Determine above and proceed to step S82.

In step S82, the initial value of the CB chromaticity coordinates (x1, y1) is set to (x1 = x0, y1 = y0).
Next, the shooting order m is set to “m = −1” (step S83), the shot number n is set to “n = k”, and the shot number j is set to “j = 1” (step S84). Here, since k = 1, the number of shots n is set to “1”.
Next, the process proceeds to step S85, and CB correction photographing processing is performed.

That is, the process proceeds to step S91 in FIG. 19, and the correction chromaticity coordinates (x, y) for CB bracket shooting are set.
Here, since x = x1 + m · j · Δx and y = y1 + m · j · Δy, x = 0.1 + (− 1) × 1 × 0.01 = 0.09, y = 0.3 + (− 1) × 1 × 0.01 = 0.29.
Next, a color temperature Ta corresponding to the set chromaticity coordinates is calculated, a subject is photographed after white balance processing is performed based on the computed color temperature, and the photographed image data is recorded in a flash memory ( Step S92 to Step S95).

Next, the process proceeds to step S86 in FIG. 18, where the number of shots j is set to “j = j + 1 = 1 + 1 = 2”, and whether the number of shots j (j = 2) is equal to or greater than the number of shots n (n = 1). Is determined (step S87). Here, since the number of shots j is larger than the number of shots n, it is determined that the number of shots j is greater than or equal to the number of shots n, and the process proceeds to step S74 in FIG. 17 to perform other key processing and display processing.
The chromaticity coordinates (x, y) of the specified partial area of the third image captured when the correction order is 0 + -order are (0.09, 0.29).

As described above, according to the third embodiment, skin color balance bracket shooting and color balance bracket shooting are performed according to the correction interval, correction order, and number of corrections set by the user. In this case, it is possible to shoot a plurality of images having different skin colors and colors in one shooting.
Also, even if the skin color when automatically set is not the desired skin color, you can select an image with the desired skin color from the bracketed images, so you can choose your favorite skin color and color The probability of obtaining an image having high is increased, and a photo opportunity is not missed.

As in the second embodiment, after performing skin color balance and color balance so as to obtain the skin color and color desired by the user, skin color balance bracket shooting and color balance bracket shooting are performed based on the skin color and color. You may make it perform.
In addition, bracket photography is performed by changing the chromaticity coordinates little by little (bracketing), but by changing the spectral reflectance characteristic R2 (λi) or the color temperature Ta little by little, the chromaticity coordinates are changed. You may make it change brackets and perform bracket photography.
In this case, the user does not set the correction interval by (Δx, Δy), but sets ΔR2 (λi) or ΔTa.

Further, the chromaticity coordinates and the spectral reflectance of a plurality of images continuously photographed by bracket photographing may be individually set. That is, in this case, not a bracketing shooting but a plurality of images with different shooting conditions are continuously shot.
For example, the chromaticity coordinates of the specified partial area of the first image are (0.1, 0.3), and the chromaticity coordinates of the specified partial area of the second image are (0.1 0.31) The chromaticity coordinates of the specified partial area of the third image are (0.11, 0.29).

[Fourth Embodiment]
Next, a fourth embodiment will be described.
In the fourth embodiment, an imaging lens, a filter, and the like can be exchanged, and proper white balance is performed even when the imaging lens, a filter, and the like are exchanged.

G. Configuration of Digital Camera 1 The fourth embodiment also implements the imaging apparatus of the present invention by using a digital camera 1 having a configuration similar to that shown in FIG.
However, the function of the configuration is different in the following points.

The imaging lens 2 is a removable interchangeable lens, and a lens barrel (not shown) that protects the imaging lens 2 is provided with a microcomputer. In this microcomputer, spectral transmittance characteristics T2 (λi) of an imaging system such as a lens, a filter, and a zoom lens position are recorded.
In addition, the drive circuit 3 reads the information of the spectral transmittance characteristic T2 (λi) of the image pickup system (the image pickup lens 2 and the filter) recorded in the microcomputer, and stores the information in a memory provided in the drive circuit 3. Remember me. The drive circuit 3 also stores the current position information of the focus lens 2a and the position information of the zoom lens 2b in the memory.

The acquisition unit 26 is connected to the drive circuit 3 and the control circuit 14, and the acquisition unit 26 includes the current position information of the focus lens 2a, the position information of the zoom lens 2b, and the like stored in the memory of the drive circuit 3. The information of the spectral transmittance characteristic T2 (λi) of the imaging system is acquired, and the acquired information is stored in the information memory 22.
The acquisition unit 26 acquires the current sensitivity setting information of the CCD 7 sent from the control circuit 14 and stores the acquired sensitivity setting information in the information memory 22.

The ROM 24 further includes a spectral transmittance characteristic T1 (λi) of the measurement optical system (an optical system such as the prism diffraction grating 17 and a filter), a spectral sensitivity characteristic S1 (λi) of the sensor array 18, and sensitivity setting information of the CCD 7. Of the spectral sensitivity characteristic S2 (λi).
The stimulus value calculator 23 reads the spectral energy distribution L1 (λi) stored in the energy distribution table memory 21 (first acquisition means), and the spectral transmittance characteristic T1 (λi of the measurement system recorded in the ROM 24. ) (Photometric transmittance acquisition means) and the spectral sensitivity characteristic S1 (λi) of the sensor array are read (photometric sensitivity acquisition means), and the read spectral energy distribution L1 (λi) and spectral transmittance characteristic T1 (λi) ) And the spectral sensitivity characteristic S1 (λi), a simulation calculation of the spectral energy distribution L0 (λi) of the light source is performed (first calculation means).
Here, FIG. 20 shows an example of the spectral transmittance characteristic of the lens, the spectral transmittance characteristic of the filter (amber color, blue color), and the spectral sensitivity characteristic of the CCD 7.

FIG. 21A shows the state of the spectral energy distribution L1 (λi) output from the sensor array 18 through the measurement optical system such as the prism diffraction grating 17 as the spectral energy distribution L0 (λi) of the light source. .
As is apparent from this figure, the spectral energy distribution L0 (λi) of the light source is influenced by the spectral transmittance characteristic T1 (λi) of the measurement optical system and the spectral sensitivity characteristic S1 of the sensor array 18, and from the sensor array 18. The output spectral energy distribution L1 (λi) is not the same as the spectral energy distribution L0 (λi) of the light source, and the spectral energy distribution L1 (λi) output from the sensor array 18 is L1 (λi) = L0 (λi) · T1 (λi) · S1 (λi).
Therefore, the spectral energy distribution L0 (λi) of the light source can be obtained by Equation 7.

Then, the stimulus value calculation unit 23 acquires the spectral transmittance characteristic T2 (λi) of the imaging optical system such as the lens and filter acquired by the acquisition unit 26 and stored in the information memory 23, and the zoom lens position, and the acquisition unit. 26, the spectral transmittance characteristic T2 (λi) of the appropriate imaging optical system is acquired from the information memory 22 by taking into account the current position of the zoom lens 2b and the like stored in the information memory 23 (imaging transmission transmission). Rate acquisition means). Further, the spectral sensitivity characteristic S2 (λi) of the CCD 7 recorded in the ROM 24 is acquired from the current sensitivity setting information of the CCD 7 acquired by the acquisition unit 26 and stored in the information memory 22 (imaging sensitivity acquisition means).
Then, the stimulus value calculation unit 23 calculates from the CCD 7 from the acquired spectral transmittance characteristic T2 (λi) of the imaging optical system, the spectral sensitivity transmittance characteristic S2 (λi) of the CCD 7, and the calculated spectral energy distribution L0 (λi) of the light source. A simulation calculation of the output spectral energy distribution L2 (λi) is performed (acquisition means).

FIG. 21B shows the state of the spectral energy distribution L2 (λi) output from the CCD 7 via the imaging optical system such as the imaging lens 2 as the spectral energy distribution L0 (λi) of the light source.
As can be seen from the figure, the spectral energy distribution L0 (λi) of the light source is influenced by the spectral transmittance characteristic T2 (λi) of the imaging optical system and the spectral sensitivity characteristic S2 (λi) of the CCD 7, and is output from the CCD 7. The spectral energy distribution L2 (λi) can be obtained according to Equation 8.

  When the spectral reflectance characteristic R2 (λi) of the subject is known, the spectral energy distribution L2 (λi) may be obtained in consideration of this. In this case, the spectral energy distribution L2 (λi) can be obtained according to Equation 9.

The stimulus value calculation unit 23 reads the color matching function from the ROM 24, reads the color matching functions (λi), (λi), (λi) and the spectral energy distribution L2 (λi) obtained by the simulation calculation. And the sum of the multiplication results for each wavelength (λi) over the entire n bands (i = 0 to n−1) of the wavelength region, thereby obtaining tristimulus values R, G, and B.
Others are the same as those in the first embodiment, and a description thereof will be omitted.

H. Operation of Digital Camera 1 The operation of the digital camera 1 according to the first embodiment will be described with reference to the flowcharts of FIGS.
In step S101, the spectral transmittance characteristic T1 (λi) of the measurement optical system and filter and the spectral sensitivity characteristic S1 (λi) of the sensor array 18 recorded in advance in the ROM 24 are read and set.

Next, photometric processing is performed (step S102), and spectral distribution data L1 (λi) for each wavelength is acquired from incident light received by the sensor array 18 (step S1033).
Next, based on the acquired spectral distribution data L1 (λi), the spectral transmittance T1 (λi) of the measurement optical system and filter set in step S1 and the spectral sensitivity characteristic S1 (λi) of the sensor array 18, the incident light source The energy distribution L0 (λi) is calculated according to Equation 7 (step S104).

Next, the position information of the focus lens 2a and the zoom lens 2b from the drive circuit 3, and the lenses and filters acquired from the microcomputer stored in the lens barrel of the imaging lens, and the spectrum of the imaging optical system for each zoom lens position, etc. The transmission characteristic T2 (λ) is acquired, and the current sensitivity setting information of the CCD 7 is acquired from the control circuit 14 and stored in the information memory 22 (step S105).
Next, by taking into consideration the lens and filter stored in the information memory 22, the spectral transmittance characteristic T2 (λi) of the imaging optical system for each zoom lens position, the position of the zoom lens 2b, etc. The spectral transmittance characteristic T2 (λi) of the system is acquired from the information memory 22 and set. Further, in consideration of the current sensitivity setting information stored in the information memory 22, the spectral sensitivity characteristic S 2 (λi) of the appropriate CCD 7 from the spectral transmittance characteristic S 2 (λi) for each sensitivity of the CCD 7 recorded in the ROM 24. Is acquired and set (step S106).

Next, the light is output from the CCD 7 from the spectral energy distribution L0 (λi) of the light source calculated in step S104, the spectral transmittance characteristic T2 (λi) of the set imaging optical system, and the spectral sensitivity characteristic S2 (λi) of the CCD 7. A simulation calculation of the spectral energy distribution L2 (λi) of the imaging signal is performed according to Equation 8 (step S107).
Next, tristimulus values R, G, and B are calculated according to Equation 1 or Equation 2 from the calculated spectral energy distribution L2 (λi) and the color matching function of the RGB color system (Step S108).

Next, the calculated tristimulus values of the RGB color system are converted into tristimulus values X, Y, and Z of the XYZ color system (step S109). This conversion is performed according to Equation 3. Note that the tristimulus value XYZ may be obtained directly from the spectral energy distribution L2 (λi) using a color matching function of the XYZ color system.
Next, the chromaticity coordinates (x, y, z) are calculated from the tristimulus values X, Y, Z according to Equation 4 (step S110).
Next, when the chromaticity coordinates are converted, the deviation Δuv from the chromaticity coordinates and the color temperature Ta and the black body radiation locus is calculated (step S111). Since the calculation of the color temperature Ta and the deviation Δuv is a well-known technique (for example, by a technique such as the International Lighting Association), a description thereof will be omitted.
Further, a conversion table such as chromaticity coordinates and color temperature Ta as shown in FIG. 2 may be recorded in the ROM 24, and the color temperature Ta or the like may be obtained by referring to the conversion table.

Next, it is determined whether or not the obtained deviation Δuv is within an allowable range (step S112). This determination is made by determining whether or not the obtained deviation Δuv is smaller than a threshold value recorded in the ROM 24, and if it is smaller than the threshold value, it is determined that it is within an allowable range.
If it is determined that it is within the allowable range (branch to Y in step S112), the white balance is controlled based on the color temperature obtained in step S11 (step S113).
On the other hand, if it is determined that it is not within the allowable range, it is determined that the color temperature measurement has failed, and error processing is performed.

  As described above, in the fourth embodiment, the spectral transmittance characteristic T2 (λi) of the imaging optical system such as the interchangeable lens of the imaging system or the zoom position of the zoom lens, and the spectral sensitivity characteristic S2 (λi of the CCD 7). ), The spectral transmittance characteristic T1 (λi) of the measurement optical system and the spectral sensitivity characteristic S1 (λi) of the sensor array are obtained, and the spectral energy distribution L2 (λi) output from the CCD 7 is simulated. Even when a lens, an external filter, or the like is replaced, the position of the zoom lens 2b or the like is changed, or the sensitivity setting of the CCD 7 is changed, the white balance processing of the image pickup signal can be performed accurately and automatically. .

In the fourth embodiment, the spectral energy distribution L0 (λi) of the light source light is obtained by simulation calculation. However, as in the first embodiment, the spectral energy distribution of the light source light is not obtained. The spectral energy distribution stored in the energy distribution table memory 21 via the prism diffraction grating 18 or the like may be handled as the spectral energy distribution of the light source light.
Also, after performing white balance according to the fourth embodiment, skin color balance and color balance as described in the second embodiment, and skin color balance bracket shooting as described in the third embodiment, You may make it perform color balance bracket imaging | photography. That is, the fourth embodiment may be combined with the second and third embodiments.

In addition, the spectral transmittance characteristic T2 (λi) of the imaging system is recorded in advance in a microcomputer provided in the lens barrel, and the spectral transmittance characteristic T2 (λi) is acquired. The product number, standard, and identification ID of the lens and filter are recorded in the microcomputer, and the spectral transmittance characteristic T2 (λi) corresponding to the ID is acquired by acquiring the ID and the like. Also good. In this case, needless to say, a plurality of spectral transmittance characteristics T2 (λi) corresponding to the ID number or the like are recorded in advance in the ROM 24 or the like.
In addition, when it is difficult to mount a microcomputer on the imaging lens 2, the model number, standard, specification, etc. of the lens or filter are displayed as a standard input by operating the user's key input unit 16, or a list is displayed. Then, by setting the selected standard or the like, the spectral transmittance characteristic T2 (λi) corresponding to the set standard may be acquired. In this case, needless to say, a plurality of spectral transmittance characteristics T2 (λi) corresponding to the standard or the like are recorded in advance in the ROM 24 or the like.

  In the first to third embodiments, the spectral energy distribution stored in the energy distribution table memory 21 via the prism diffraction grating 18 and the like is treated as the spectral energy distribution of the light source light. As shown in the embodiment, the spectral energy distribution L0 (λi) of the light source light may be obtained by simulation calculation to perform white balance processing.

Further, the white balance device in the first and second embodiments may be a recording medium or the like that cannot shoot a subject, and may be any device that has a function of processing image data.
In addition, the white balance device in the third and fourth embodiments is not limited to a digital camera, and may be a mobile phone with a camera, a PDA with a camera, a personal computer with a camera, or a digital video camera. Any device can be used as long as it can photograph a subject.

1 is a block diagram of a digital camera according to an embodiment of the present invention. It is a figure which shows the conversion table of chromaticity coordinate (x, y, z) and color temperature Ta. It is a figure which shows the characteristic data of the relative intensity of color temperature Ta and RGB component. It is the figure which showed the mode when controlling the gain adjustment part 11. FIG. It is a flowchart which shows operation | movement of the digital camera of 1st Embodiment. The spectral energy distribution for every incident wavelength and the example of the spectral energy distribution table memorize | stored in energy distribution table memory are shown. FIG. 4 is a diagram illustrating color matching functions (λi), (λi), (λi) of an RGB color system and a color matching function table recorded in a ROM 24. FIG. 4 is a diagram illustrating color matching functions (λi), (λi), (λi) of an XYZ color system and a color matching function table recorded in a ROM 24. FIG. 6 is a diagram showing an example of spectral reflectance recorded in a ROM 24. It is a flowchart which shows operation | movement of the digital camera of 2nd Embodiment. It is a flowchart which shows operation | movement of the digital camera of 2nd Embodiment. It is a figure which shows the example of the chromaticity coordinate displayed with the through image of the to-be-photographed object. It is a figure which shows the example when the Munsell color system and CIELAB uniform color space are displayed. It is the figure which showed the structure of the digital camera by the external photometry system by an RGB sensor. It is the figure which showed the structure of the digital camera by CCD internal photometry system. It is a flowchart which shows operation | movement of the digital camera of 3rd Embodiment. It is a flowchart which shows operation | movement of the digital camera of 3rd Embodiment. It is a flowchart which shows operation | movement of the digital camera of 3rd Embodiment. It is a flowchart which shows operation | movement of the digital camera of 3rd Embodiment. It is a figure which shows the example of the spectral transmittance characteristic of a lens, the spectral transmittance characteristic of a filter, and the spectral sensitivity characteristic of CCD7. It is a figure which shows the mode of the spectral energy distribution of the spectral energy distribution output from the spectral energy distribution of the light source light, the sensor array, and CCD7 in 4th Embodiment. It is a flowchart which shows operation | movement of the digital camera of 4th Embodiment. It is a flowchart which shows operation | movement of the digital camera of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Imaging lens 3 Drive circuit 4 Shutter / shutter 5 Vertical driver 6 TG
7 CCD
DESCRIPTION OF SYMBOLS 8 Sample hold circuit 9 Analog-digital converter 10 Color separation circuit 11 Gain adjustment part 12 Image signal processing part 13 Memory 14 Control circuit 15 Display part 16 Key input part 17 Prism diffraction grating 18 Sensor array 19 Amplifier 20 Analog-digital converter 21 Energy Distribution table memory 22 Information memory 23 Stimulus value calculation unit 24 ROM
25 Chromaticity coordinate calculation unit 26 Acquisition unit 27 Color temperature calculation unit 28 White balance control unit 29 Chromaticity coordinate / color temperature information memory

Claims (2)

An acquisition means for acquiring an imaging signal;
And Table示制control means Ru is displayed on the display means an image of the obtained image signal by the acquisition unit,
A designation means for the user to designate a partial area of the image displayed on the display means;
A calculation detecting means that to calculate the chromaticity coordinates of the partial region from the image signal of a portion designated area by the specifying means,
The display control means displays a chromaticity diagram together with the image of the imaging signal and the chromaticity coordinates calculated by the calculating means on the chromaticity diagram with a coordinate cursor, and the user displays the chromaticity displayed on the display means. A setting means for setting the chromaticity coordinates of the partial area designated by the designation means to a desired value by correcting the coordinate cursor indicating the chromaticity coordinates on the drawing;
As chromaticity coordinates of a partial region calculated by the pre-hexane detection means is chromaticity coordinates set by the setting unit, the white balance by controlling the gain of the obtained image signal by the acquisition unit White balance control means for controlling
An image processing apparatus comprising: To a computer that controls an acquisition device that acquires an imaging signal and an image processing device that includes a display device,
The display device in Table示制control function Ru display the image of the obtained image signal by the acquisition device,
A designation function for the user to designate a partial area of the image displayed on the display device;
Calculated out function to calculate the chromaticity coordinates of the partial region from the image signal of a portion designated area by the specifying function,
The display control function displays a chromaticity diagram together with the image of the imaging signal and the chromaticity coordinates calculated by the calculation function on the chromaticity diagram with a coordinate cursor, and the user displays the chromaticity displayed on the display device. A setting function for setting the chromaticity coordinates of the partial area designated by the designation function to a desired value by correcting the coordinate cursor indicating the chromaticity coordinates on the diagram;
As chromaticity coordinates of some calculated area by pre hexane output function is chromaticity coordinates set by the setting function, the white balance by controlling the gain of the obtained image signal by the acquisition device White balance control function to control
A program to realize

Images