JP4710319B2 - Imaging apparatus and program thereof - Google Patents

Description

The present invention relates to an imaging apparatus having a white balance adjustment function and a program thereof .

There are various types of light sources for photographing, such as natural light in a clear sky, natural light in a cloudy state, a fluorescent lamp, an incandescent lamp, and the like, and a color cast is generated depending on the type of the light source. For this reason, in an imaging apparatus such as a digital camera, the white balance is adjusted to an appropriate white balance so that white appears as pure white. In particular, digital cameras that automatically adjust the white balance are widely used. Conventional auto white balance includes an external sensor method (incident method) for adjusting white balance by an external colorimetric sensor and an internal photometric method (reflection method) for adjusting white balance by an image sensor. In any method, the light source is identified by detecting the ratio of red, green, and blue in the output signal of the external colorimetric sensor or image sensor, and the output signal of the image sensor is corrected with a correction value suitable for that light source. The gain is adjusted or the balance of the color difference component is adjusted.
Japanese Patent Laid-Open No. 3-291091 JP-A-8-32990 JP 2000-224608 A JP 2001-2111457 A

  However, outdoor cloudy weather and shades of trees, shades, and fluorescent lights all cast blue and green, so these light sources are often mistakenly identified, and specific chromatic colors such as sunsets and blue curtains are often used in the internal metering method. The white balance adjustment accuracy may be inferior when the subject is full of the screen.

Therefore, the present invention has been made to solve the above-described problems, and an imaging apparatus capable of accurately adjusting white balance even when a specific chromatic subject fills the screen. And to provide the program .

In order to solve the above problems, the invention described in claim 1 is directed to an imaging unit that images a subject, an ultraviolet intensity measuring unit that measures the intensity of ultraviolet rays, and a photographing light source based on a measurement result of the ultraviolet intensity measuring unit. In an imaging apparatus comprising: a photographic light source determination unit that determines the image quality; and a setting unit that sets a white balance based on the photographic light source determined by the photographic light source determination unit, the imaging unit includes a number of pixels arranged in a matrix. An image pickup device having pixels and a photographing lens that forms an image of a subject on the pixels of the image pickup device, the image pickup device is located at the center of a pixel region in which a large number of pixels are arranged in a matrix; An effective pixel region in which an image of a subject imaged in the region by the photographing lens is read out as an image acquired by the imaging device, and in the vicinity of the effective pixel region And an ultraviolet intensity measurement pixel region for measuring the intensity of the ultraviolet rays input through the photographing lens, and each of the pixels in the ultraviolet intensity measurement pixel region is similar to the effective pixel region. A first region covered with any of red, green, and blue color filters arranged in a predetermined pattern, and a second region where each pixel is not covered with any of the color filters, The ultraviolet intensity measuring means is means for measuring the intensity of ultraviolet rays based on the intensity of light in the first area and the intensity of light in the second area of the ultraviolet intensity measuring pixel area. An imaging device.

According to a second aspect of the present invention, there is provided color temperature measuring means for measuring the color temperature of a subject, and the photographing light source judging means judges the photographing light source based on the ultraviolet intensity measuring means and the color temperature measuring means. The imaging apparatus according to claim 1, wherein:

A third aspect of the present invention is the imaging apparatus according to the first or second aspect , wherein the ultraviolet intensity measuring pixel region is provided so as to surround the periphery of the effective pixel region .
According to a fourth aspect of the present invention, in the pixel region for ultraviolet intensity measurement, a pixel region adjacent to the effective pixel region is the first region. An imaging apparatus according to claim 1.

According to a fifth aspect of the invention, the ultraviolet intensity measuring means measures the intensity of the ultraviolet light by subtracting the light intensity of the first region from the light intensity of the second region of the ultraviolet intensity measuring pixel region. an image pickup apparatus according to any one of claims 1 to 4, characterized in that means.

According to a sixth aspect of the invention, the photographing direction in front of the imaging device, according to any one of claims 1 to 5, characterized in that it comprises a filter for cutting infrared light received by the image pickup device An imaging device.

A seventh aspect of the present invention is the imaging apparatus according to the second aspect, wherein the photographing light source determination means can determine the environment of cloudy weather, shade, and fluorescent light.

According to a seventh aspect of the present invention, an imaging lens and an image of a subject imaged in the region by the photographing lens are located in a central portion of a pixel region in which a large number of pixels are arranged in a matrix. And an effective pixel region that is read out as an image acquired by the method, and an ultraviolet intensity measurement pixel region that is positioned in the vicinity of the effective pixel region and that measures the intensity of the ultraviolet rays input through the photographing lens. An image sensor, and the ultraviolet intensity measurement pixel region is covered with any one of a red, green, and blue color filter in which each pixel is arranged in a predetermined pattern like the effective pixel region. and regions, the computer in which each pixel is mounted on the imaging apparatus also includes a second region which is not covered in any of the color filter, first territory of the ultraviolet intensity measuring pixel area Based on the intensity of light and the intensity of light of the second region, the process of measuring the intensity of the ultraviolet, a process for determining the photographing light source based on a measurement result of the ultraviolet intensity on the determination the imaging light source And a process for setting a white balance based on the program.

According to the present invention, since the type of the light source is determined based on the ultraviolet intensity, it is possible to improve the determination accuracy of the light source and adjust the white balance suitable for the type of the light source.
Further, since the pixel area in the vicinity of the effective pixel area of the image sensor is the ultraviolet intensity measurement pixel area, it is not necessary to provide a separate ultraviolet detection sensor in the digital camera 1, and the ultraviolet intensity measurement pixel area is Similar to the effective pixel area, the first area covered with any one of the red, green, and blue color filters in which each pixel is arranged in a predetermined pattern, and each pixel is not covered with any of the color filters. Therefore, the number of parts and the manufacturing cost of the digital camera 1 can be prevented from increasing.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

[First Embodiment]
FIG. 1 is a block diagram of an imaging apparatus, for example, a digital camera 1 according to the present invention.

  The digital camera 1 includes a photographing lens 2, a shutter 4, an infrared cut filter 6, an RGB color filter 7A, a visible light cut filter (ultraviolet light passing filter) 7B, an image sensor 8, an internal circuit 10, and an operation unit. 12 and a display unit 14.

  The photographing lens 2 is a zoom lens or a single focus lens, and forms an external subject image on the image sensor 8. The taking lens 2 is provided with a diaphragm 16 for adjusting the aperture of the light beam. In the case of a zoom lens, the photographing lens 2 is driven by a lens driving device (not shown) so that the focal length is adjusted.

  The shutter 4 is a mechanical shutter whose opening / closing operation and traveling speed are controlled based on an electric signal from a control circuit 40 described later, and adjusts an exposure time for the image sensor 8. It should be noted that the shutter 4 can be omitted when an image sensor 8 described later has an electronic shutter function.

  The infrared cut filter 6 shields light in the infrared wavelength band, and the wavelength band of light transmitted through the infrared cut filter 6 is about 300 to 780 nm. The color filter 7A is a filter in which R (red), G (green), and B (blue) are passed in a matrix, and the visible light cut filter 7B has a wavelength band of about 400 to 780 nm. The light is cut and ultraviolet light (wavelength band of about 300 to 400 nm is allowed to pass through).

  The image pickup device 8 is a CCD type solid-state image pickup device. A subject image is formed on a large number of pixels arranged in a matrix, and an electric signal of the subject image is sent to the internal circuit 10 by a readout pulse from a drive circuit (not shown). Is to be read.

  FIG. 2A is a plan view of the light receiving surface of the image sensor 8. As shown in FIG. 2A, the peripheral portion of the image sensor 8 is a rectangular frame-shaped carbon black region 82, and the carbon black region 82 is covered with light-shielding carbon black. The central portion of the image sensor 8 is a rectangular effective pixel region 84 in which matrix-like pixels are arranged. The effective pixel region 84 is formed by a color filter 7A in which red, green, and blue are arranged in a predetermined pattern. It is covered. An image formed on the effective pixel region 84 is an image acquired by the image sensor 8.

  A light receiving sensor 81 such as a photodiode is disposed in a rectangular frame region between the effective pixel region 84 and the carbon black region 82. The light receiving sensor 81 is covered with the visible light cut filter 7B. Yes. That is, in the light receiving sensor 81, the wavelength band of about 400 to 780 nm is cut by the visible light cut filter 7B out of the wavelength band of about 300 to 780 nm transmitted through the infrared cut filter 6, so that the ultraviolet wavelength band (300 to 400) is cut. It will receive light.

  FIG. 2B is a plan view showing another example of the image sensor 8. As in FIG. 2A, the peripheral edge of the image sensor 8 is a rectangular frame-shaped carbon black region 82, and the carbon black region 82 is covered with light-shielding carbon black. Pixels are also formed in a rectangular frame region between the carbon black region 82 and the effective pixel region 84, and this region is divided into a non-filter region 86 and a dummy pixel region 90.

  The non-filter region 86 is a region that is not covered with any filter, and light in the wavelength band (about 300 to 780 nm) that has passed through the infrared cut filter 6 enters the pixels of the non-filter region 86 as it is. The dummy pixel area 90 is covered with red, green, and blue color filters in a predetermined pattern for each pixel. Since the wavelength band of blue to red is approximately 400 to 780 nm, the intensity of the ultraviolet light can be measured by subtracting the intensity (luminance) of the dummy pixel area 90 from the intensity (luminance) of the non-filter area 86.

  As described above, the intensity (light quantity) of ultraviolet rays can be detected by using any one of the image pickup devices 8 in FIGS. 2 (a) and 2 (b).

  Returning to FIG. 1, although not shown, the operation unit 12 includes various operation members for operating the camera, such as a shutter button, a dial, a cross key, a cancel key, a lever, and a push button. Is output to the internal circuit 10.

  The display unit 14 includes a color liquid crystal display panel or an electroluminescence display panel, and performs display based on a display signal output from the internal circuit 10.

  The internal circuit 10 operates based on an input from the operation unit 12 and performs various function processes as a camera such as autofocus processing, photometry processing, white balance control processing, still image shooting processing, moving image shooting processing, and reproduction processing. Is.

  In the autofocus process, when the shutter button of the operation unit 12 is half-pressed, the distance to the subject is obtained based on the information of a distance measuring sensor (not shown) or the image signal input from the image sensor 8, and the photographing lens 2 is moved back and forth. This is the process of moving to and focusing.

  The photometric process is a process of measuring an EV value by measuring a subject based on information from a photometric sensor (not shown) or an image signal input from the image sensor 8 when the shutter button of the operation unit 12 is half-pressed.

  The white balance control process determines the type (color temperature) of an external light source based on information of a color temperature measurement sensor (not shown) or an image signal input from the image sensor 8 when the shutter button of the operation unit 12 is pressed halfway. The processing according to the color temperature is performed. Details of the white balance control process will be described later.

  In the still image shooting process, when the shutter button of the operation unit 12 is fully pressed in the still image mode, a signal of a subject image is read from the image sensor, and various processes described in detail later such as a white balance control process are performed. This is a process for recording a still image in the memory 46.

  In the moving image shooting process, in the moving image mode, the image signal of the image sensor 8 is used as frame image data at a predetermined time interval, that is, a moving image, from the time when the shutter button of the operation unit 12 is fully pressed until the next time it is fully pressed. Is recorded in the image memory 46.

  The reproduction process is a process of reading a still image or moving image recorded in the image memory 46 and displaying the read still image or moving image on the display unit 14.

  Next, the configuration of each part of the internal circuit 10 will be specifically described.

  An image signal (R (red) signal, G (green) signal, B (blue) signal) and UV (ultraviolet) signal photoelectrically converted for each pixel in the image sensor 8 is a CDS / AGC (noise reduction / automatic gain) circuit. The image signal is sequentially output to the signal 22 and sampled and held by the CDS / AGC circuit 22, and the gain is automatically adjusted.

  The A / D conversion unit 24 converts the image signal input from the CDS / AGC circuit 22 into a digital signal having a predetermined bit, and outputs the digital image signal to the color separation unit 26.

  The color separation unit 26 separates the image signal input from the A / D conversion unit 24 into R signal, G signal, B signal, and UV signal for each pixel. The R signal is output to the gain adjustment unit 32 and the color temperature detection and control value setting unit 30, the G signal is output to the image signal processing unit 36, and the B signal is output to the gain adjustment unit 34 and the color temperature detection and control value setting unit 30. The UV signal is output to the ultraviolet intensity calculation unit 28.

  The ultraviolet intensity calculation unit 28 calculates the intensity of ultraviolet rays based on the UV signal input from the color separation unit 26, and the intensity signal is output to the indoor / outdoor determination unit 29. The indoor / outdoor determination unit 29 determines whether it is outdoor shooting or indoor shooting from the intensity signal of the ultraviolet light, and outputs the determination signal to the color temperature detection and control value setting unit 30.

  (A) of FIG. 3 is a table comparing the results of measuring the intensity of ultraviolet rays when using incandescent lamps and fluorescent lamps in various climatic conditions and indoors. The intensity of ultraviolet rays in fine weather is 2000 (microwatt / square centimeter). ) Is “100”, the ratio under each measurement condition is shown, and (b) is a graph of the ratio.

  As is clear from FIGS. 3 (a) and 3 (b), in the outdoors, the minimum value “4” is incandescent lamps and fluorescent lamps regardless of whether it is sunny, cloudy, rainy, or shade / shade. The maximum value of 0.5 is greatly exceeded. Based on this, the indoor / outdoor determination unit 29 has the threshold value for determination set to the value “2”, and if it is “2” or less, the indoor and outdoor determination signal is detected as a color temperature detection and outdoor determination signal. The data is output to the control value setting unit 30.

  The color temperature detection and control value setting unit 30 receives the RGB signal from the color separation unit 26, detects the color temperature, and stores a control value for performing white balance correction according to the detection result in an internal memory (not shown). The stored control value is output to the white balance control unit 38. In this case, when the color temperature is determined to be sunny (sunlight), cloudy, or incandescent, the respective correction values are output to the white balance control unit 38, and when it is determined to be other than this (shade / shade) In the case of an indoor determination signal, the correction value of the fluorescent lamp is output to the white balance control unit 38, and the outdoor determination signal In this case, the shade / shade correction value is output to the white balance control unit 38.

  The white balance control unit 38 outputs the gain control signal Rg to the gain adjustment unit 32 and the gain control signal Bg to the gain adjustment unit 34 according to the correction value given from the color temperature detection and control value setting unit 30.

  The gain adjustment unit 32 and the gain adjustment unit 34 adjust the white balance of the R signal and the B signal respectively input from the color separation unit 26 using the gain control signals Rg and Bg, and the adjusted R-Out signal and B-Out signal are obtained. This is output to the image signal processing unit 36.

  The image signal processing unit 36 generates a luminance signal and a color signal from the input R-Out signal, G signal, and B-Out signal, and outputs them to the image memory 46. The image memory 46 is an internal memory composed of a flash memory or the like, or a removable memory card or the like, and stores an image signal given from the image signal processing circuit 36.

  The control circuit 40 includes a CPU, a RAM, a ROM, a compression / decompression circuit, and the like. Then, the signal stored in the image memory 46 from the image signal processing unit 36 is immediately read out and supplied to the control circuit 40, converted into an image signal compressed in accordance with, for example, the JPEG standard, and stored again in the image memory 46. Is done. The control circuit 40 includes a display control unit 44 that controls the display unit 14. The display control unit 44 corrects the signal read from the image memory 46 based on the chromaticity coordinate information or the color temperature information 48 and outputs it to the display unit 14 to display an image on the display unit 14. It is. For this reason, the chromaticity coordinate information or the color temperature information 48 is configured to be given and stored with a correction value from the color temperature detection and control value setting unit 30.

  The digital camera 1 can manually set the white balance mode instead of detecting the color temperature of the subject and automatically performing white balance correction. That is, the control circuit 40 receives a white balance setting unit 42, and in accordance with a signal input from the operation unit 12 operated by the user, a plurality of light source modes (auto white balance mode, clear sky mode, overcast mode, One mode can be selected from among shade / shade mode, incandescent mode, and fluorescent mode.

  The auto white balance mode is a mode in which a correction value is obtained from the color temperature of the subject as described above to perform white balance correction. However, when a mode other than the auto white balance mode is set, the white balance control unit 38 is set. Outputs a gain Rg corresponding to the light source mode set by the white balance setting unit 42 to the gain adjustment unit 32 and outputs a gain Bg corresponding to the light source mode to the gain adjustment unit 34 to perform white balance correction. .

  The operation of the digital camera 1 when the user selects and sets the auto white balance mode by operating the operation unit 12 in the above configuration will be described.

  When the user presses the shutter button of the operation unit 12 halfway, the internal circuit 10 executes autofocus processing, photometry processing, and auto white balance correction value detection processing.

  In other words, in the autofocus process, the distance to the subject is obtained based on information from a distance measuring sensor (not shown) or the image signal input from the image sensor 8, and the photographing lens 2 is moved back and forth to focus. In the photometric process, the subject is photometrically measured based on information from a photometric sensor (not shown) or an image signal input from the image sensor 8, and the EV value is measured, and the aperture amount of the aperture 16 is set according to the EV value.

  Subsequently, in the auto white balance correction value detection processing, light incident on the image sensor 8 is photoelectrically converted by the image sensor 8, and an image signal for each pixel is sequentially output from the image sensor 8 to the CDS / AGC circuit 22. The signal is sampled and held by the CDS / AGC circuit 22 and automatically gain adjusted, the image signal is digitally converted by the A / D converter 24, and the image signal is converted into a UV signal, R signal, G signal, and B signal by the color separator 26. To be separated.

  Then, the UV signal is output to the ultraviolet intensity calculation unit 28, and the ultraviolet intensity is calculated from the UV signal by the ultraviolet intensity calculation unit 28.

  Next, a signal indicating the ultraviolet intensity calculated and detected by the ultraviolet intensity calculation unit 28 is sent to the indoor / outdoor discrimination unit 29, and the discrimination signal is sent to the color temperature detection and control value setting unit 30.

  The color temperature detection and control value setting unit 30 receives the RGB signals from the color separation unit 26, detects the color temperature, and stores a control value for performing white balance correction according to the detection result in an internal memory. Output to the white balance control unit 38. In this case, when the color temperature is determined to be sunny (sunlight), cloudy, or incandescent, the respective correction values are output to the white balance control unit 38, and when it is determined to be other than this (shade / shade) In the case of an indoor determination signal, the correction value of the fluorescent lamp is output to the white balance control unit 38, and the outdoor determination signal In this case, the shade / shade correction value is output to the white balance control unit 38.

  When the user half-presses the shutter button of the operation unit 12, the above-described processing is performed. When the user further presses the shutter button, the internal circuit 10 performs still image shooting processing. That is, a signal is sent from the image sensor 8 to the color separation unit 26 via the CDS / ADS circuit 22 and the A / D conversion unit 24, and an RGB signal is output from the color separation circuit 26. At this time, the white balance control unit 38 is given the white balance correction value stored in the internal memory of the color temperature detection and control value setting unit 30 by half-pressing the shutter button. Since the gain control signals Rg and Bg corresponding to the correction values are output, the R signal input from the color separation unit 26 to the gain adjustment unit 32 is subjected to white balance adjustment by the gain control signal Rg and further gain adjustment. The B signal input to the unit 34 is white balance adjusted by the gain control signal Bg. The G signal and the adjusted R-Out signal and B-Out signal are processed by the image signal processing unit 36, recorded as image data in the image memory 46, and read out from the image memory 46 for control. It is sent to the circuit 40, subjected to compression processing, and stored again in the image memory 46. At the same time, the image is displayed on the display unit 14 by the display control unit 44 of the control unit 40.

  As described above, according to the first embodiment of the present invention described above, the ultraviolet intensity is detected by the photodiode 81 provided in the image sensor 8 or the pixel in the ultraviolet detection region 86 of the image sensor 8, and the ultraviolet intensity is detected. Since the type of the light source is determined based on the above, the type of the light source can be accurately specified. Therefore, it is possible to adjust to an appropriate white balance.

  Further, since the ultraviolet ray detection means is provided in the image pickup device 8 itself, it is not necessary to provide a separate ultraviolet ray detection sensor in the digital camera 1, so that it is possible to prevent an increase in the number of parts and manufacturing cost of the digital camera 1.

[Second Embodiment]
In the digital camera 1 according to the first embodiment, the image sensor 8 is provided with ultraviolet detection means to detect the ultraviolet intensity, but the digital camera 201 shown in the block diagram of FIG. An ultraviolet sensor 250 is provided. Hereinafter, the digital camera 201 will be described. In the digital camera 201, a part corresponding to any part of the digital camera 1 according to the first embodiment is assigned a lower two-digit common number.

  In the digital camera 201, the matrix circuit 252 includes a G signal from the color separation unit 226, an R-Out signal from the gain adjustment unit 232, and a B-Out signal from the gain adjustment unit 234 as a Y signal, an RY signal, and a BY. It converts to a signal. Before the white balance adjustment, the R signal of the color separation unit 226 is output from the gain adjustment unit 232 as the R-Out signal, and the B signal of the color separation unit 226 is the gain adjustment unit 234 as the B-Out signal. Is output from.

  The image signal processing unit 236 generates a luminance signal and a color signal from the Y (luminance) signal, RY (color difference) signal, and BY (color difference) signal of the matrix circuit 252, and sends them to the control circuit 240 and the image memory 246. Output.

  The integrating unit 254 integrates the RY signal of the matrix circuit 252 and outputs the integrated signal to the color temperature detection and control value setting unit 230, and integrates the BY signal of the matrix circuit 252 to detect the color temperature and set the control value. Output to the unit 230. Instead of the integration unit 254, an averaging unit that calculates an addition average value of the RY signal and the BY signal may be used.

  The ultraviolet sensor 250 has a UV photodiode and the like, and is a sensor that detects the intensity of ultraviolet rays.

  The integrating unit 256 integrates the ultraviolet intensity detected by the ultraviolet sensor 250. Instead of the integration unit 256, an averaging unit that calculates an addition average value of ultraviolet intensity may be used.

  The ultraviolet intensity calculator 228 calculates the ultraviolet intensity from the integrated value of the integrator 256.

  The color temperature detection and control value setting unit 230 detects the color temperature of the subject based on the ultraviolet intensity calculated by the ultraviolet intensity calculation unit 228, the integrated value of the RY signal, and the integrated value of the BY signal. The light source is determined, and a white balance correction value corresponding to the determined light source is output to the white balance control unit 238.

  The white balance control unit 238 outputs the gain control signal Rg to the gain adjustment unit 232 based on the correction value corresponding to the type of the light source determined by the color temperature detection and control value setting unit 230, and also detects the color temperature and the control value. A gain control signal Bg corresponding to the type of light source determined by the setting unit 230 is output to the gain adjustment unit 234.

  Also in the second embodiment, since the ultraviolet intensity is detected by the ultraviolet sensor 250 and the type of the light source is determined based on the ultraviolet intensity, the white balance adjustment appropriate for the type of the light source is performed on the R signal and B signal of the image sensor 208. Can do.

[Third Embodiment]
FIG. 5 shows a block diagram of a third embodiment according to the present invention. In the digital camera 301 shown in the block diagram of FIG. 5, an ultraviolet sensor 350 is provided separately from the image sensor 308. Further, the digital camera 301 is separately provided with light receiving sensors 360, 362, and 364 for color temperature detection. Hereinafter, the digital camera 301 will be described. In the digital camera 301, a part corresponding to any part of the digital camera 1 according to the first embodiment is assigned a lower two-digit common number.

  In this digital camera 301, the light receiving sensor 360 is covered with a red color filter, and detects the intensity of the red component of visible light. The light receiving sensor 362 is covered with a green color filter and detects the intensity of the green component of visible light. The light receiving sensor 364 is covered with a blue color filter and detects the intensity of the blue component of visible light. External light is condensed on the light receiving sensors 360, 362, 364 by the condenser lens 366.

  The integrating unit 368 integrates the R signal of the light receiving sensor 360, the G signal of the light receiving sensor 362, and the B signal of the light receiving sensor 364, and outputs them to the color temperature detection and control value setting unit 330. Instead of the integration unit 368, an averaging unit that calculates an average addition value of the R signal, the G signal, and the B signal may be used.

  The ultraviolet sensor 350 includes a UV photodiode and the like, and is a sensor that detects the intensity of ultraviolet rays.

  The integrating unit 356 integrates the ultraviolet intensity detected by the ultraviolet sensor 350. Instead of the integration unit 356, an averaging unit that calculates an addition average value of ultraviolet intensity may be used.

  The ultraviolet intensity calculation unit 328 calculates the ultraviolet intensity from the integrated value of the integration unit 356.

  The color temperature detection and control value setting unit 330 is based on the UV intensity calculated by the UV intensity calculation unit 328 and the integration value of the R signal, the integration value of the G signal, and the integration value of the B signal from the integration unit 368. The color temperature, that is, the type of the light source is determined, and a control value corresponding to the type of the light source is supplied to the white balance control unit 38. In this case, when the color temperature is determined to be sunny (sunlight), cloudy, or incandescent, the respective correction values are output to the white balance control unit 338, and when it is determined that the color temperature is other than this (shade / shade) (Or fluorescent lamp) is determined based on the UV intensity calculated by the UV intensity calculation unit 328, whether it is a fluorescent lamp or a shade / shade. If it is determined to be a fluorescent lamp, the correction value of the fluorescent lamp is white balance controlled. When the result is output to the unit 338 and the shade / shade is determined, the correction value of the shade / shade is output to the white balance control unit 338.

  The white balance control unit 338 outputs gain control signals Rg, Gg, and Bg based on the supplied correction value to the gain adjustment units 332, 370, and 334, respectively.

  The gain adjustment units 332, 370, and 334 adjust the gain of the RGB signals input from the color separation unit 326 based on the gain control signals Rg, Gg, and Bg, and adjust the adjusted R-Out, G-Out, and B-Out, respectively. The signal is output to the image signal processing unit 336.

  As described above, also in the third embodiment, since the ultraviolet intensity is detected by the ultraviolet sensor 350 and the type of the light source is determined based on the ultraviolet intensity, the R signal, the G signal, and the B signal of the image sensor 308 are used as the light source. It is possible to adjust the white balance appropriate for the type.

  The present invention is not limited to the above embodiments, and various improvements and design changes may be made without departing from the spirit of the present invention. For example, as shown in FIG. In addition, since the ultraviolet intensity is different in the case of fine weather and rainy weather or in the fine weather and shade of trees / shade, it is also possible to make the discrimination based on the difference in ultraviolet intensity.

  Furthermore, in each of the above embodiments, the ultraviolet intensity is directly compared with the threshold value, but the ultraviolet intensity is indirectly measured by measuring the ratio of the ultraviolet intensity to the entire wavelength band of the light source and comparing the ratio with the threshold value. Of course, it may be compared with the threshold value, and each process such as comparison with the threshold value can be performed by a flowchart of a microprogram.

  In the above embodiments, the image sensors 8, 208, and 308 are CCD image sensors, but may be MOS image sensors. When a MOS type image sensor is used, peripheral circuits (for example, a drive circuit, a CDS / AGC circuit, etc.) are appropriately changed for the MOS type image sensor.

  Further, in each of the above embodiments, the example in which the present invention is applied to a digital camera has been described. However, the present invention can also be applied to a video camera, or an imaging function such as a mobile phone with an imaging function, a wristwatch, a PDA, or a personal computer. Any electronic device provided is applicable.

1 is a block diagram of a digital camera 1 according to the present invention. It is a top view of the light-receiving surface of the image pick-up element 8 of FIG. It is the graph which showed the ultraviolet-ray intensity of the various light sources with respect to clear sunlight. It is a block diagram of the digital camera 201 by the 2nd Embodiment of this invention. It is a block diagram of the digital camera 301 by 3rd Embodiment similarly.

Explanation of symbols

1, 201, 301 Digital camera 6 Infrared cut filter 8, 208, 308 Image sensor 88 UV detection area 250, 350 UV sensor 30, 230, 330 Color temperature detection and control value setting unit 38, 238, 338 White balance control unit 32 , 34, 232, 234, 332, 334, 370 Gain adjuster

Claims (8)

Imaging means for imaging a subject;
Ultraviolet intensity measuring means for measuring the intensity of ultraviolet rays;
A photographing light source judging means for judging a photographing light source based on a measurement result of the ultraviolet intensity measuring means;
Setting means for setting a white balance based on the photographing light source determined by the photographing light source determining means;
In an imaging apparatus comprising:
The imaging means includes an imaging device having a large number of pixels arranged in a matrix and a photographing lens that forms an image of a subject on the pixels of the imaging device,
The image sensor is located at the center of a pixel area where a large number of pixels are arranged in a matrix, and an image of a subject imaged in the area by the photographing lens is read out as an image acquired by the image sensor. An effective pixel region, and an ultraviolet intensity measurement pixel region that is located in the vicinity of the effective pixel region and measures the intensity of ultraviolet rays input through the photographing lens,
The ultraviolet intensity measurement pixel area includes a first area covered with any one of red, green, and blue color filters in which each pixel is arranged in a predetermined pattern as in the effective pixel area, and each pixel includes the A second region not covered by any of the color filters,
The ultraviolet intensity measuring means is means for measuring the intensity of ultraviolet rays based on the intensity of light in the first area and the intensity of light in the second area of the pixel area for measuring ultraviolet intensity. Imaging device. A color temperature measuring means for measuring the color temperature of the subject;
The imaging apparatus according to claim 1, wherein the imaging light source determination unit determines the imaging light source based on a measurement result of the ultraviolet intensity measurement unit and a measurement result of the color temperature measurement unit. The imaging apparatus according to claim 1, wherein the ultraviolet intensity measurement pixel region is provided so as to surround the effective pixel region . Pixel region adjacent to the effective pixel region in the ultraviolet intensity measuring pixel area, image pickup apparatus according to any one of claims 1 to 3, characterized in that has a first region. The ultraviolet intensity measuring means is a means for measuring the intensity of ultraviolet rays by subtracting the intensity of light in the first area from the intensity of light in the second area of the pixel area for measuring ultraviolet intensity.
The imaging apparatus according to any one of claims 1 to 4, wherein the imaging apparatus is characterized in that The imaging apparatus according to any one of claims 1 to 5, further comprising a filter that cuts infrared rays of light received by the imaging element in front of the imaging direction of the imaging element. The imaging apparatus according to claim 2, wherein the photographing light source determination unit can determine a cloudy sky, a shade, and an environment of a fluorescent lamp. An imaging lens and an image of a subject imaged in the area by the imaging lens are read out as an image acquired by the imaging element, at the center of a pixel area where a large number of pixels are arranged in a matrix. An image sensor having an effective pixel area and an ultraviolet intensity measurement pixel area for measuring the intensity of the ultraviolet light input through the photographing lens located in the vicinity of the effective pixel area; Similar to the effective pixel region, the ultraviolet intensity measuring pixel region includes a first region covered with any one of a red, green, and blue color filter in which each pixel is arranged in a predetermined pattern, In a computer mounted on an imaging device having a second region that is not covered with any of the color filters ,
A process of measuring the intensity of ultraviolet light based on the intensity of light in the first area and the intensity of light in the second area of the pixel area for ultraviolet intensity measurement ;
A process of determining a photographing light source based on the measurement result of the ultraviolet intensity ;
A process of setting a white balance based on the determined photographic light source;
A program characterized by having executed.

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