JP2005348301A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera accurately photographing even an object of quick movement, without any limitation in an expandable dynamic range. <P>SOLUTION: The digital camera comprises a means for acquiring photography images of two kinds of light exposure volumes with exposure by one mechanical shutter operation. Magnification of a dynamic range is performed by synthesizing two images of different exposure. Since photography images of two kinds of light exposure volumes are acquired with exposure by one mechanical shutter operation, the camera photographs even an object of quick movement accurately. Since a shutter speed for each exposure can be freely set, the degree of freedom for an accumulation time is large. Magnification of the dynamic range is performed by synthesizing those two images of different exposure after reading from an imaging device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital camera.

  Conventionally, two images with different exposure amounts are combined to expand the dynamic range. As a method therefor, for example, several proposals such as Japanese Patent Publication No. 6-83400, Japanese Patent Publication No. 8-17455, Japanese Patent Application Laid-Open No. 4-140895, and the like have been proposed. Japanese Patent Publication No. 6-83400 combines two images with different exposure amounts on the transfer line of the image sensor to expand the dynamic range. Japanese Patent Publication No. 8-17455 combines two images with different exposure amounts in the blanking period and the normal field period to expand the dynamic range. Japanese Patent Laid-Open No. 4-168895 changes the saturation charge level to synthesize two images with different exposure amounts on the charge accumulating portion of the image sensor to expand the dynamic range. However, in these methods, the degree of freedom of the accumulation time is small, and there is a limitation on the hardware of the image sensor in the dynamic range that can be expanded when adding on the charge accumulation unit or transfer line, and to solve them As shown in the conventional method of FIG. 3, exposure is performed by two mechanical shutter operations, and two images with different exposure amounts are combined to expand the dynamic range. Here, the exposure amount is an integral value within the Ta and Tb times of the EXP signal.

  However, conventionally, as shown in the conventional method of FIG. 3, since exposure by two mechanical shutter operations is required, the subject needs to be stopped between the two exposures, and each shutter speed is Even when it was early, subjects with fast movement were not good at it. An object of the present invention is to provide a digital camera that eliminates such inconvenience, is strong against a fast-moving subject, has a large degree of freedom in accumulation time, and has no restriction on the dynamic range that can be expanded.

  Therefore, in this proposal, using the image sensor disclosed in Japanese Patent Laid-Open No. 2000-201355, there is provided means for obtaining a photographed image having two types of exposure amounts by one exposure by a mechanical shutter operation. Synthesize images and expand dynamic range. Since exposure is performed with a single mechanical shutter operation, two types of exposures are obtained, so it is strong against fast-moving subjects, and the shutter speed for each exposure can be set at any time, so the storage time is free. These two images with different degrees of exposure and read out from the image sensor are combined and expanded to expand the dynamic range, so that it is possible to present a digital camera with no limitation on the expandable dynamic range.

  As can be easily understood from the above description, according to the present invention, there is provided means for obtaining a photographed image of two kinds of exposure amounts by exposure by one mechanical shutter operation, and two images having different exposure amounts are provided. By combining the images and expanding the dynamic range, a single mechanical shutter operation can be used to obtain two types of exposure images, so it is strong against fast-moving subjects and the shutter speed for each exposure. Since each can be set at any time, the degree of freedom of the accumulation time is large, and these two images with different exposure amounts are combined after being read out from the image sensor to expand the dynamic range. It is possible to present an unlimited digital camera.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

  In FIG. 1, reference numeral 100 denotes an image processing apparatus.

  Reference numeral 10 denotes a photographing lens, 12 denotes an exposure control device having an aperture and shutter function, and 14 denotes an image sensor that converts an optical image into an electrical signal. The sensitivity can be changed by control of the system control circuit 50. Here, the image sensor 14 will be described with reference to FIG. The image sensor 14 is an image sensor disclosed in Japanese Patent Application Laid-Open No. 2000-201355. The image sensor 14 includes a color filter with a primary color Bayer array of two vertical repetitions, and performs 3: 1 interlacing to make one frame first, second, and third. It consists of 3 fields.

  Reference numeral 16 denotes an A / D converter that converts an analog signal output from the image sensor 14 into a digital signal.

  A timing generation circuit 18 supplies a clock signal and a control signal to the image sensor 14, the A / D converter 16, and the D / A converter 26, and is controlled by the memory control circuit 22 and the system control circuit 50.

  An image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22.

  Further, the image processing circuit 20 performs predetermined calculation processing using the captured image data, and the system control circuit 50 controls the exposure control means 40 and the distance measurement control means 42 based on the obtained calculation result. TTL (through-the-lens) AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash pre-flash) processing.

  Further, the image processing circuit 20 performs predetermined arithmetic processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained arithmetic result.

  A memory control circuit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing circuit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / decompression circuit 32.

  The data of the A / D converter 16 is written into the image display memory 24 or the memory 30 via the image processing circuit 20 and the memory control circuit 22 or the data of the A / D converter 16 is directly passed through the memory control circuit 22. It is.

  Reference numeral 24 denotes an image display memory, 26 denotes a D / A converter, and 28 denotes an image display unit composed of a TFT LCD or the like. Display image data written in the image display memory 24 passes through the D / A converter 26. Displayed by the image display unit 28.

  If the image data captured using the image display unit 28 is sequentially displayed, the electronic viewfinder function can be realized.

  Further, the image display unit 28 can arbitrarily turn on / off the display according to an instruction from the system control circuit 50. When the display is turned off, the power consumption of the image processing apparatus 100 can be greatly reduced. I can do it.

  Reference numeral 30 denotes a memory for storing captured still images and moving images, and has a sufficient storage capacity to store a predetermined number of still images and a predetermined time of moving images.

  Thereby, even in the case of continuous shooting or panoramic shooting in which a plurality of still images are continuously shot, it is possible to write a large amount of images to the memory 30 at high speed.

  The memory 30 can also be used as a work area for the system control circuit 50.

  Reference numeral 32 denotes a compression / decompression circuit that compresses and decompresses image data by adaptive discrete cosine transform (ADCT) or the like, reads an image stored in the memory 30, performs compression processing or decompression processing, and stores the processed data in the memory 30. Write to.

  Reference numeral 40 denotes exposure control means for controlling the exposure control apparatus 12 having an aperture and shutter function.

  Reference numeral 42 denotes a distance measurement control means for controlling the focusing of the photographing lens 10, reference numeral 44 denotes a zoom control means for controlling zooming of the photographing lens 10, and reference numeral 46 denotes an image stabilization control means for controlling the operation of the optical image stabilization means 102 which is a means for correcting shake. It is a control means. The anti-vibration control means includes a normal mode with high power consumption but good tracking characteristics and an economy mode with low power consumption but slightly poor tracking characteristics.

Reference numeral 48 denotes a dummy load, which is used when performing a battery load test.
The exposure control means 40 and the distance measurement control means 42 are controlled using the TTL method, and based on the calculation result obtained by calculating the captured image data by the image processing circuit 20, the system control circuit 50 performs the exposure control means 40 and the distance measurement. Control is performed on the control means 42.

  Reference numeral 50 denotes a system control circuit that controls the entire image processing apparatus 100, and reference numeral 52 denotes a memory that stores constants, variables, programs, and the like for operation of the system control circuit 50.

  Reference numeral 54 denotes a display unit such as a liquid crystal display device or a speaker that displays an operation state or a message using characters, images, sounds, or the like in accordance with execution of a program in the system control circuit 50. One or a plurality of places are provided near the portion where they can be easily seen, and for example, a combination of an LCD, an LED, a sound generation element, and the like is used.

  The display unit 54 has a part of its function installed in the optical viewfinder 104.

  Among the display contents of the display unit 54, what is displayed on the LCD or the like includes single shot / continuous shooting display, self-timer display, compression rate display, number of recorded pixels, number of recorded pixels, number of remaining images that can be captured, shutter Speed display, Aperture value display, Exposure compensation display, Flash display, Red-eye reduction display, Macro shooting display, Buzzer setting display, Clock battery level display, Battery level display, Error display, Multi-digit number information display and recording There are a display state of the media 200 and 210, a communication I / F operation display, a date / time display, and the like.

  Among the display contents of the display unit 54, what is displayed in the optical viewfinder 104 includes in-focus display, camera shake warning display, flash charge display, shutter speed display, aperture value display, exposure correction display, and the like.

  Reference numeral 56 denotes an electrically erasable / recordable nonvolatile memory, such as an EEPROM.

  Reference numerals 60, 62, 64, 66, 68 and 70 are operation means for inputting various operation instructions of the system control circuit 50, and may be a single unit such as a switch, a dial, a touch panel, pointing by line-of-sight detection, a voice recognition device, or the like. Consists of multiple combinations.

  Here, a specific description of these operating means will be given.

  Reference numeral 60 denotes a mode dial switch, which can be switched to set each function mode such as power-off, automatic shooting mode, shooting mode, panorama splicing shooting mode, playback mode, multi-screen playback / erase mode, and PC connection mode.

  Reference numeral 62 denotes a shutter switch SW1, which is turned ON during the operation of a shutter button (not shown), and performs AF (auto focus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, EF (flash pre-flash) processing, and the like. Instruct to start operation.

  Reference numeral 64 denotes a shutter switch SW2, which is turned on when the operation of a shutter button (not shown) is completed, and an exposure process for writing a signal read from the image sensor 12 to the memory 30 via the A / D converter 16 and the memory control circuit 22. Development processing using operations in the image processing circuit 20 and the memory control circuit 22, recording processing for reading image data from the memory 30, compression in the compression / decompression circuit 32, and writing the image data to the recording medium 200 or 210. Instructs the start of a series of processing operations.

  Reference numeral 66 denotes an image display ON / OFF switch, which can set ON / OFF of the image display unit 28.

  With this function, when photographing using the optical viewfinder 104, it is possible to save power by cutting off the current supply to the image display unit including a TFT LCD or the like.

  Reference numeral 68 denotes image quality mode setting means for making settings relating to image quality and recording capacity, such as the compression rate and size of the recorded image.

  70 is an operation unit composed of various buttons, a touch panel, etc., a menu button, a set button, a macro button, a multi-screen playback page break button, a flash setting button, a single shooting / continuous shooting / self-timer switching button, menu movement + (plus) Button, menu shift- (minus) button, playback image shift + (plus) button, playback image- (minus) button, shooting image quality selection button, exposure correction button, date / time setting button, and the like.

  80 is a power control means, which is composed of a battery detection circuit, a DC-DC converter, a switch circuit for switching a block to be energized, etc., and detects the presence / absence of a battery, the type of battery, the remaining battery level, and the detection result In addition, the DC-DC converter is controlled based on an instruction from the system control circuit 50, and a necessary voltage is supplied to each part including the recording medium for a necessary period.

  Reference numeral 82 denotes a connector, 84 denotes a connector, and 86 denotes a power source means including a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, or an AC adapter.

  90 and 94 are interfaces with a recording medium such as a memory card or a hard disk, 92 and 96 are connectors for connecting to a recording medium such as a memory card or a hard disk, and 98 is a recording medium 200 or 210 attached to the connector 92 or 96. Recording medium attachment / detachment detecting means for detecting whether or not the recording medium is present.

  In this embodiment, it is assumed that there are two interfaces and connectors for attaching the recording medium. Of course, the interface and the connector for attaching the recording medium may have a single or a plurality of systems, any number of systems. Moreover, it is good also as a structure provided with combining the interface and connector of a different standard.

  The interface and the connector may be configured using a PCMCIA card, a CF (Compact Flash (registered trademark)) card, or the like that conforms to a standard.

  Further, when the interfaces 90 and 94, and the connectors 92 and 96 are configured using a PCMCIA card or a CF (Compact Flash (registered trademark)) card or the like, LAN cards, modem cards, USB cards, IEEE1394 Management data attached to image data and image data can be transferred to and from peripheral devices such as other computers and printers by connecting various communication cards such as cards, P1284 cards, SCSI cards, and PHS communication cards. I can meet each other.

  Reference numeral 102 denotes an optical image stabilization unit that prevents image blur and is controlled by the image stabilization control unit 46.

  Reference numeral 104 denotes an optical viewfinder, which can take an image using only the optical viewfinder without using the electronic viewfinder function of the image display unit 28. In the optical viewfinder 104, some functions of the display unit 54, for example, a focus display, a camera shake warning display, a flash charge display, a shutter speed display, an aperture value display, an exposure correction display, and the like are installed.

  A communication unit 110 has various communication functions such as RS232C, USB, IEEE1394, P1284, SCSI, modem, LAN, and wireless communication.

  Reference numeral 112 denotes a connector for connecting the image processing apparatus 100 to another device by the communication unit 110 or an antenna in the case of wireless communication.

  Reference numeral 200 denotes a recording medium such as a memory card or a hard disk.

  The recording medium 200 includes a recording unit 202 composed of a semiconductor memory, a magnetic disk, or the like, an interface 204 with the image processing apparatus 100, and a connector 206 for connecting to the image processing apparatus 100.

  Reference numeral 210 denotes a recording medium such as a memory card or a hard disk.

  The recording medium 210 includes a recording unit 212 composed of a semiconductor memory, a magnetic disk, and the like, an interface 214 with the image processing apparatus 100, and a connector 216 that connects to the image processing apparatus 100.

  Next, examples of the present invention will be described.

  First, FIG. 2 will be described. FIG. 2A shows the color filter array of the image sensor 14 used in this embodiment, which includes a color filter of a primary color Bayer array of two vertical repeats, and performs a 3: 1 interlace to make one frame first, It consists of 3 fields, 2nd and 3rd fields. For example, when only the first field is read out, the result is as shown in FIG. 2 (b). In normal shooting, the first, second, and third fields are sequentially read out as shown in FIG. 2 (a). The images are processed after being arranged in the same array as the image sensor array to obtain a captured image.

  Next, FIG. 3 will be described. First, the signal will be described from above. HD is a vertical synchronization signal supplied from the timing generation circuit 18 to the image sensor 14 and the like. VD is a vertical synchronization signal supplied from the timing generation circuit 18 to the image sensor 14 and the like. SG is a vertical transfer signal supplied from the timing generation circuit 18 to the image pickup device 14 and the like, and moves the charge accumulated in the charge storage section of the image pickup device 14 to the vertical transfer path and the charge transferred to the vertical transfer path. Performs the vertical transfer operation. SUB is a signal that is supplied from the timing generation circuit 18 to the image sensor 14 and the like and that removes the charges accumulated in the charge accumulation unit of the image sensor 14. SHOPN is a signal for opening the shutter supplied from the exposure control means 40 to the exposure control device 12 having an aperture and shutter function. In actuality, the shutter starts to move after a signal is input, and then opens completely after a while. . The SHCLS is a signal for closing the shutter supplied from the exposure control means 40 to the exposure control device 12 having an aperture and shutter function. In actuality, the shutter starts to move after a signal is input, and is completely closed after a while. . EXP schematically represents the state of exposure, and the integral amount of the aperture diameter and the exposure time at the aperture diameter within the Ta, Tb, Tc, and Td times is the respective exposure amount.

  Next, the operation of the conventional method will be described over time. The SG signal is output at T1, the charge stored in the charge storage section of the image sensor 14 is transferred to the vertical transfer path, and the charge transferred to the vertical transfer path is transferred vertically. After that, the SUB signal and the SHCLS signal are coordinated to perform Ta time exposure. Then, the accumulated charge exposed for Ta time at T2 is transferred to the vertical transfer path, and the charge transferred to the vertical transfer path is transferred vertically. At this time, the vertically transferred line signal is sent to the image processing circuit 20, the memory control circuit 22 and the like through the A / D converter 16 by a horizontal transfer pulse (not shown). If you open the shutter during this time, smear will occur, so keep it closed. Then, the SG signal is output at T3, the charge accumulated in the charge accumulation portion of the image sensor 14 is transferred to the vertical transfer path, and the charge transferred to the vertical transfer path is vertically transferred. Then, the SUB signal and the SHCLS signal are coordinated to perform exposure for Tb time. Then, the accumulated charge exposed for Tb time at T4 is transferred to the vertical transfer path, and the charge transferred to the vertical transfer path is transferred vertically. At this time, the vertically transferred line signal is sent to the image processing circuit 20, the memory control circuit 22 and the like through the A / D converter 16 by a horizontal transfer pulse (not shown). If you open the shutter during this time, smear will occur, so keep it closed. By the above operation, an image exposed for Ta and Tb time is obtained.

  Next, the operation of the method of this embodiment will be described with time. The SG signal is output at T1, the charge stored in the charge storage section of the image sensor 14 is transferred to the vertical transfer path, and the charge transferred to the vertical transfer path is transferred vertically. Then, the SUB signal is coordinated so that Tc time elapses until T2, and exposure is performed for Tc time. Here, the exposure amount in the Tc period is equal to the exposure amount in the Ta period. At T2, a signal for transferring the charge accumulated in the charge accumulation section of the SG signal to the vertical transfer path is output at T2, and the charge of the first field accumulated in the charge accumulation section of the image sensor 14 is moved to the vertical transfer path. . However, the charges transferred to the vertical transfer path are not vertically transferred here as in the conventional example. Then, the SUB signal and the SHCLS signal are coordinated to perform exposure for Td time. Here, the exposure amount in the Td period is equal to the exposure amount in the Tb period. At T3, the charges that have already been transferred to the vertical transfer path at T2 are transferred vertically. At this time, the vertically transferred line signal is sent to the image processing circuit 20, the memory control circuit 22 and the like through the A / D converter 16 by a horizontal transfer pulse (not shown). If you open the shutter during this time, smear will occur, so keep it closed. Then, the charge accumulated in the second field exposed for the time Td at T4 is transferred to the vertical transfer path, and the charge transferred to the vertical transfer path is transferred vertically. At this time, the vertically transferred line signal is sent to the image processing circuit 20, the memory control circuit 22 and the like through the A / D converter 16 by a horizontal transfer pulse (not shown). If you open the shutter during this time, smear will occur, so keep it closed. Then, the charge stored in the third field exposed for Td time at T5 is transferred to the vertical transfer path, and the charge transferred to the vertical transfer path is transferred vertically. At this time, the vertically transferred line signal is sent to the image processing circuit 20, the memory control circuit 22 and the like through the A / D converter 16 by a horizontal transfer pulse (not shown). If you open the shutter during this time, smear will occur, so keep it closed. By the above operation, an image exposed for Tc and Td time is obtained. As described above, in this method, Tc and Td start at the same time and the mechanical shutter operates once, so that there is no difference other than the exposure time between the two exposures, and it is strong against fast-moving subjects.

  Next, the first processing operation of the exposure image will be described with reference to FIG. First, the exposure image in the Tc period is composed of the first field as shown in FIG. 2B, and this image is set as the first exposure image. Here, in the final image, RGB three-color data is required for each pixel. For example, in the case of G pixel of (4) in the first exposure image, G has data for that pixel. R is the left and right, and B is the average of the top and bottom. In addition, in the case of B pixel of (7) in the first exposure image, B has the data of that pixel, use that, G is left and right, R is diagonal upper right, upper left average and diagonal lower right, lower left The average value of. Also, in the case of the R pixel of (10) in the first exposure image, since R has the data of that pixel, use that, G is left and right, B is diagonally upper right, upper left average and diagonally lower right, lower left The average value of. The exposure image in the Td period is composed of the second field and the third field as shown in FIG. 2C, and this image is used as the second exposure image. Here, in order to create a dynamic range expanded image together with the first exposure image, two images having different centers of gravity with different exposure times are required. For example, the G pixel of (4) of the first exposure image In order to create a pixel with the same center of gravity, RGB three-color data is required in the middle position between B in (3) and B in (5) in the second exposure image, and B has data for that pixel. Is used as the average value of (3) and (5), G is the average value of the left and right averages of (3) and (5), R is the average of diagonally upper right and upper left of (3), and (5) The average value of the lower right and lower left averages. Also, to create a pixel with the same center of gravity as the B pixel in (7) of the first exposure image, RGB three-color data is placed between the G of (6) and G of (8) in the second exposure image. Necessary, because G has the data of that pixel, use it as the average value of (6) and (8), R is the average value of the left and right average of (6) and (8), B is the top and bottom Average value. Also, in order to create a pixel with the same center of gravity as the R pixel in (10) of the first exposure image, RGB three-color data is placed in the middle position between (9) G and (11) G in the second exposure image. Necessary, because G has the data of that pixel, use it as the average value of (9) and (11), B is the average value of the left and right average of (9) and (11), R is the upper and lower Average value. As described above, RGB three-color data is obtained for all pixels.

  In the above embodiment, an example of a CCD image sensor with an RGB filter has been described, but the second processing operation when a CCD image sensor with a complementary color filter is used is also described. First, the exposure image in the Tc period consists of the first field as shown in FIG. 4B, and this image is the first exposure image. Here, in the final image, RGB three-color data is required for each pixel, and CMYG four-color data must be prepared for each pixel in order to calculate it. For example, in the case of the C pixel of (4) in the first exposure image, since there is data for C, use that, Y is left and right, M is up and down, G is diagonally upper right, and upper left average and diagonal The average value of the lower right and lower left averages. Also, in the case of M pixel of (7) in the first exposure image, there is data of M, so use that, G is left and right, C is up and down, Y is diagonally upper right, upper left average and diagonal The average value of the lower right and lower left averages. Also, in the case of Y pixel of (10) in the first exposure image, Y has data of that pixel, so use that, C is left and right, G is up and down, M is diagonally upper right, upper left average and diagonal The average value of the lower right and lower left averages. The exposure image in the Td period is composed of the second field and the third field as shown in FIG. 4C, and this image is used as the second exposure image. Here, in order to create a dynamic range enlarged image together with the first exposure image, two images having different centroids with different exposure times are required. For example, the pixel C in (4) of the first exposure image. In order to make a pixel with the same center of gravity, CMYG four-color data is required in the middle position between M in (2) and M in (5) in the second exposure image. Is the average value of (3) and (5), G is the average value of the left and right averages of (3) and (5), C is the average value of the top and bottom, Y is the diagonally upper right and upper left of (3) The average value of the average and the average of (5) diagonally lower right and lower left. Also, in order to create a pixel with the same center of gravity as the M pixel in (7) of the first exposure image, CMYG four-color data is required at the intermediate position between C in (6) and C in (8) of the second exposure image. Since C has the data of that pixel, use it as the average value of (6) and (8), Y is the average value of the left and right average of (6) and (8), M is the average of the top and bottom The value, G, is the average value of (6) diagonal upper right and upper left averages and (8) diagonal lower right and lower left averages. Also, to create a pixel with the same center of gravity as the Y pixel in (10) of the first exposure image, CMYG four-color data is required in the middle position between G in (9) and G in (11) of the second exposure image. Since G has the data for that pixel, use it as the average of (9) and (11), M is the average of the left and right averages of (9) and (11), and Y is the average of the top and bottom The value C is the average of (9) diagonal upper right and upper left averages and (11) diagonal lower right and lower left averages. Then, RGB three-color data is calculated from the CMYG four-color data obtained for all pixels.

  A third processing operation using the CCD image sensor of the complementary color filter will be described below with reference to FIG. First, the exposure image in the Tc period consists of the first field as shown in FIG. 5B, and this image is set as the first exposure image. Here, in the final image, RGB data for each pixel is required for each pixel. For example, the virtual image is located at the center of gravity of the G and M pixels in (1) and the Y and C pixels in (2) in the first exposure image. Assuming this pixel, the data of the centroid position can be obtained by calculating RGB three-color data from these four color values. The exposure image in the Td period is composed of the second field and the third field as shown in FIG. 5C, and this image is used as the second exposure image. Here, in order to create a dynamic range enlarged image together with the first exposure image, two images having different centroids with different exposure times are required. For example, (1) G, M of the first exposure image In order to create a pixel with the same center of gravity as the center of gravity of the Y and C pixels in (4), RGB from the four color values of Y and C in (2) and G and M in (3) of the second exposure image Calculate three-color data. Also, in order to create a pixel with the same center of gravity as the center of gravity of the pixels of (4) Y and C in the first exposure image and G and M of (7), G and M in (5) of the second exposure image The RGB three-color data is calculated from the values of the four colors Y and C in (6). In addition, in order to create a pixel having the same centroid as the centroid of the (7) M and G of the first exposure image and the (10) C and Y pixels, the C, Y and (8) of the second exposure image The RGB three-color data is calculated from the four color values of M and G in (9). Then, RGB three-color data is calculated from the CMYG four-color data obtained for all pixels.

  Here, by performing both of the second and third processing operations, it is possible to obtain twice as many pixel data, and only one-third of the number of pixels of the image sensor can be obtained in the single operation. However, by performing both, it is possible to obtain an image with 2/3 the number of pixels.

  As described above, two images with different exposure times are obtained and combined to create a dynamic range expanded image. In the synthesis method, first, pixel data of an image with a short exposure time is normalized according to the ratio of the exposure times of the two sheets. For example, if the exposure time for two images is 1/60 seconds and 1/30 seconds, the exposure time is 1/60 seconds by doubling the pixel data of the image with an exposure time of 1/60 seconds. Normalized to 30 seconds of data. Then, the luminance difference is obtained for all the pixels of the two normalized images, and the maximum luminance value that minimizes the luminance difference is obtained. Then, by replacing the pixel data whose luminance value is larger than the maximum value among the pixels of the image actually exposed in 1/30 seconds with the data normalized to 1/30 seconds, the dynamic range expanded image Get.

It is a configuration block diagram of an embodiment of the present invention. It is the color filter arrangement | sequence of the image pick-up element used in a present Example. It is a timing diagram of the signal of a present Example. It is a color filter array of the image sensor used in the second embodiment. It is a color filter arrangement | sequence of the image pick-up element used in a 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shooting lens 12 Shutter 14 Image pick-up element 16 A / D converter 18 Timing generation circuit 20 Image processing circuit 22 Memory control circuit 24 Image display memory 26 D / A converter 28 Image display part 30 Memory 32 Image compression / decompression circuit 40 Exposure Control means 42 Distance measurement control means 44 Zoom control means 46 Anti-vibration control means 48 Dummy load 50 System control circuit 52 Memory 54 Display unit 56 Non-volatile memory 60 Mode dial switch 62 Shutter switch SW1
64 Shutter switch SW2
66 Image display ON / OFF switch 68 Image quality mode switch 70 Operation unit 80 Power supply control means 82 Connector 84 Connector 86 Power supply means 90 Interface 92 Connector 94 Interface 96 Connector 98 Recording medium attachment / detachment detection means 100 Image processing apparatus 102 Optical image stabilization means 104 Optical Finder 110 Communication means 112 Connector (or antenna)
200 Recording Medium 202 Recording Unit 204 Interface 206 Connector 210 Recording Medium 212 Recording Unit 214 Interface 216 Connector

Claims (7)

  To read out all pixels, it has an imaging sensor that reads out divided into odd-numbered n fields, has an electronic shutter and a mechanical shutter, controls the electronic shutter and the mechanical shutter, and starts exposing the plurality of fields simultaneously. The exposure time of the first field is controlled by moving the charge of the first field to the vertical transfer unit of the sensor, and the exposure amount of the field other than the first field is closed by closing the mechanical shutter. A digital camera characterized by controlling the camera.   2. The digital camera according to claim 1, wherein a dynamic range expanded image is created from the first field image and a field image other than the first field having an exposure amount different from that of the first field image.   The center of gravity of each pixel is made to coincide when creating a field image other than the first field having an exposure amount different from that of the first field image and the first field image. 2. The digital camera according to 2.   When creating a field image other than the first field having an exposure amount different from that of the first field image and the first field image, the center of gravity of each pixel is matched on each pixel. The digital camera according to claim 1 or 2.   When the field image other than the first field having a different exposure amount from the first field image and the first field image are created, the centroid of each pixel is made to coincide between the pixels. The digital camera according to claim 1 or 2.   When creating a field image other than the first field having an exposure amount different from that of the first field image and the first field image, an image in which the center of gravity of each pixel is matched on each pixel is generated. When the field image other than the first field having the exposure amount different from that of the first field image is generated, an image in which the center of gravity of each pixel is matched between the pixels is generated. 3. The digital camera according to claim 1, wherein the number of pixels is increased by synthesizing the generated images.   When creating a dynamic range expanded image from the first field image and a field image other than the first field having a longer exposure time than the first field image, depending on the exposure time ratio of the two images. Then, normalization is performed according to the image with a long exposure time to generate a normalized image, and the luminance difference between each pixel of the image with the long exposure time and the normalized image is obtained, and the luminance difference is minimized. 7. The maximum luminance value is obtained, and when the luminance value of each pixel of the image with a long exposure time is larger than the maximum luminance value, the pixel data of the normalized image is replaced. Digital camera.

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