JP2009118247A - Photographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a properly balanced image close to the expected image quantity and resolution of a user. <P>SOLUTION: A pixel adding mode setting screen is displayed (step 100), to select any of an image quality preferential mode for improving an image quality by adding pixels, while maintaining a minimum pixel number set by the user and a pixel preferred mode for adding the pixel so that the pixel number increases as much as possible, while a minimum image quality level set by the user is maintained. When selecting the image quality preferred mode, the minimum pixel number can be set (step 102 and 104); and when selecting the pixel number preferential mode, a minimum S/N level can be set (steps 106 and 108). When the image quality preferred mode is selected, the image quality is improved by adding the pixel, by increasing the pixel adding number as much as possible, while maintaining minimum pixel number; and when the pixel preferential mode is selected, the pixel number is increased by reducing the pixel adding number as much as possible, in a range which is capable of maintaining the minimum S/N level. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus capable of adding a plurality of pixels.

  2. Description of the Related Art Conventionally, in a digital camera that photographs a subject with a photographing element such as a CCD, a technique for adding a plurality of pixels in order to improve sensitivity and to prevent deterioration in image quality due to an increase in the number of pixels and an increase in the number of pixels in a recorded image Various proposals have been made.

  For example, Patent Document 1 discloses a technique for pixel addition without a special setting operation by a user.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique that can switch between a thinning readout mode in which pixels are thinned out and read out and a pixel addition mode in which pixels are added out and read out.

  Patent Document 3 discloses a technique for adding pixels so that the number of pixels is set in advance according to the shooting situation.

Patent Documents 4 to 6 disclose techniques for adding pixels so that the shutter speed is maintained on the high speed side in order to prevent camera shake.
JP 2001-359038 A JP 2003-189183 A JP 2007-13270 A JP 2006-352715 A JP 2006-352716 A JP 2006-352717 A

  However, in the technique described in Patent Document 1, since pixels are added by default, pixels may be added even when there is a sufficient amount of received light, and resolution may be reduced unnecessarily. was there.

  In addition, the technique described in Patent Document 2 has a problem that it is difficult to obtain an image with an appropriate balance of noise, dynamic range, and resolution because there is only one pixel addition pattern.

  Further, in the technique described in Patent Document 3, when the amount of exposure is small, pixels are fixedly added to the number of pixels set by the user, resulting in insufficient sensitivity, insufficient resolution, and balance. There was a problem that it might be a bad image.

  In addition, the techniques described in Patent Documents 4 to 6 do not take into consideration that the resolution is reduced due to pixel addition, and there is a problem that the number of pixels may be smaller than the user's assumption. It was.

  The present invention has been proposed to solve the above-described problems, and an object of the present invention is to provide a photographing apparatus capable of obtaining a well-balanced image close to the image quality and resolution expected by the user.

  In order to solve the above-described problem, the invention described in claim 1 is any one of a photographing element that photoelectrically converts light from a subject, a driving unit that drives the photographing element, and a plurality of predetermined pixel addition modes. A selection means for selecting whether or not, a setting means for setting a pixel addition number of image data of a photographed image photographed by the photographing element in accordance with the selected pixel addition mode, and a set pixel addition number And pixel addition means for adding pixel values of the image data of the photographed image.

  According to the present invention, there is provided selection means for selecting any one of a plurality of predetermined pixel addition modes, and image data of a photographed image photographed by the photographing element in accordance with the selected pixel addition mode. Since the pixel addition number is set and the image data of the photographed image is pixel-added by the set pixel addition number, a well-balanced image close to the image quality and resolution expected by the user can be obtained.

  In addition, as described in claim 2, the pixel addition mode includes an image quality priority mode that prioritizes the image quality of a captured image, and the selection unit determines in advance when the image quality priority mode is selected. And a minimum pixel number selection unit that selects any one of a plurality of minimum pixels. When the image quality priority mode is selected, the setting unit determines that the pixel addition number is greater than or equal to the selected minimum pixel number. You may make it set the said pixel addition number so that it may become the maximum.

  According to a third aspect of the present invention, the pixel addition mode includes a pixel number priority mode that prioritizes the number of pixels of a captured image, and the selection unit is configured to select the pixel number priority mode when the pixel number priority mode is selected. Including a minimum image quality level selection means for selecting any one of a plurality of predetermined minimum image quality levels, and the setting means, when the pixel number priority mode is selected, at the selected minimum image quality level or higher You may make it set the said pixel addition number so that a pixel addition number may become the maximum.

  According to a fourth aspect of the present invention, when the brightness of the captured image does not reach an appropriate exposure level, the pixel addition number set by the setting unit is set so as to approach the appropriate exposure level. A configuration may be further provided with adjusting means for increasing the ISO sensitivity of the captured image by adjusting the gain of the captured image.

  According to a fifth aspect of the present invention, when the brightness of the captured image does not reach the appropriate exposure level, the adjusting means for increasing the ISO sensitivity by adjusting the gain so as to approach the appropriate exposure level; Judgment means for judging whether or not the adjusted photographed image has proper exposure when the ISO sensitivity after adjustment by the adjustment means is the highest ISO sensitivity, and the setting means comprises the judgment If it is determined by the means that the exposure is not appropriate, the pixel addition number may be increased.

  Further, as described in claim 6, it may be configured to further comprise a storage means for storing a predetermined correspondence relationship between the received light amount of the photographed image and the expected S / N ratio.

  Further, as described in claim 7, the selection unit can select an auto bracket shooting mode in which captured images of a plurality of pixels are acquired for the same subject, and when the auto bracket shooting mode is selected, The pixel addition means may record the captured image by sequentially adding pixels with a plurality of predetermined pixel addition numbers.

  In addition, as described in claim 8, the imaging element includes a pixel addition function for adding and outputting signal charges of a plurality of pixels in accordance with an instruction from the driving unit, and the selection unit includes the imaging unit One of a first addition mode in which signal charges of the plurality of pixels are pixel-added by a pixel addition function of the element, and a second pixel addition mode in which image data of the photographed image is pixel-added by the pixel addition means It is good also as a structure which can be selected.

  According to the present invention, there is an effect that a well-balanced image close to the image quality and resolution expected by the user can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  (First embodiment)

  1A shows a front view of the digital camera 60 according to the present invention, and FIG. 1B shows a rear view of the digital camera 60. As shown in FIG. 3A, on the top and front of the digital camera 60, a shutter button 62 for instructing photographing, a strobe light emitting unit 64 for performing strobe exposure on the subject, and a lens opening for entering the subject image. A unit 66, an optical finder 68, and the like are arranged. Also, as shown in FIG. 5B, on the back of the digital camera 60, an LCD 51 for displaying various menu screens and through images, an optical viewfinder 68, an operation unit 70, and the like are arranged. The operation unit 70 includes various operation buttons such as a cross button 72, a menu / execution button 74, and a function button 76.

  Next, the configuration of the electrical system of the digital camera 60 will be described. FIG. 2 is a block diagram showing a schematic configuration of the electrical system of the digital camera 60.

  The digital camera 60 includes an optical system 80 to which imaging light from a subject is input, an imaging unit 20 that is disposed behind the optical axis of the optical system 80 and images the subject via the optical system 80, image processing, and overall control. A main control unit 30 for performing

  The optical system 80 includes a zoom lens 11, a diaphragm mechanism 12, a focus lens 13, and the like. The zoom lens 11 can be moved in the optical axis direction by a zoom motor (not shown) and the focus lens 13 can be moved by an auto focus motor (not shown). The aperture of the aperture mechanism 12 is controlled by an iris motor (not shown). These motors are controlled by a motor driver 14.

  The imaging unit 20 generates a subject image signal in accordance with imaging light from the optical system 80, and a correlation unit 2 that removes noise components included in the image signal read from the CCD image sensor 21. A CDS circuit 22 that performs a double sampling (CDS) process, a digital / analog converter (hereinafter referred to as an A / D converter) 23 that converts an analog signal processed by the CDS circuit 22 into a digital signal, And a timing generator (TG) 24 that generates a timing signal for driving the CCD image sensor 21.

  The main control unit 30 includes various circuits connected to each other via a bus 31. Specifically, the main control unit 30 includes an image input control unit 32 that supplies the image data from the A / D converter 23 to the bus 31, and image processing that performs predetermined digital signal processing on the input image data. A circuit 33, a VRAM 34 for storing image data representing an image to be displayed, and an LCD control unit 35 for performing control to display an image based on the image data stored in the VRAM 34 on the LCD 51 are provided.

  Further, the main control unit 30 detects the contrast value used to adjust the focus of the focus lens 13, and an AE (Auto Exposure) detection that detects the optimum exposure and white balance based on the image data. A circuit 37, an EEPROM (Electrically Erasable Programmable Read Only Memory) 38 in which various parameters such as various programs and the number of recorded pixels of the photographed image are stored, an SDRAM (Synchronous Dynamic Random Access Memory) 39 used as a work memory, an image A compression / expansion circuit 40 that compresses / decompresses data, a media control unit 41 that reads / writes various information from / to the recording medium 52, and a CPU 42 that appropriately reads information from the EEPROM 38 and controls the above-described units.

  The AF detection circuit 36 detects, for example, a contrast value of image data input from the imaging unit 20 and stored in the VRAM 34 when the shutter button 62 is half-pressed, as an AF evaluation value. The contrast value represents the degree of focus on the subject. For this reason, the in-focus position is obtained when the contrast value is maximized.

  The AE detection circuit 37 detects an exposure value (EV value) representing the brightness of the subject based on image data of a captured image when the shutter button 62 is half-pressed, for example. The EV value is used as a photometric value when obtaining the aperture and shutter speed.

  In the digital camera 60 configured as described above, the analog signal representing the subject image output from the CCD image sensor 21 when the shutter button 62 is half-pressed is processed by the CDS circuit 22 and is then output by the A / D converter 23. After being converted into a digital image signal, the image data is input from the image input control unit 32 into the main control unit 30 as image data. The input image data is temporarily stored in the SDRAM 39 via the bus 31.

  In the main control unit 30, the AF detection circuit 36 calculates the contrast value based on the image data stored in the SDRAM 39, and the AE detection circuit 37 performs the AE calculation. Based on these calculation results, the CPU 42 moves the focus lens 13 to the in-focus position via the motor driver 14, and appropriate exposure control values (aperture value and shutter speed) of the aperture mechanism 12 and the CCD image sensor 21. To set the AWB adjustment value.

  When the shutter button 62 is fully pressed, the analog signal representing the subject image output from the CCD image sensor 21 is processed by the CDS circuit 22 in the same way as when the shutter button 62 is half-pressed, and the A / D converter 23 performs the processing. After being converted into a digital image signal, the image data is input from the image input control unit 32 into the main control unit 30 as image data. The input image data is temporarily stored in the SDRAM 39 via the bus 31 and subjected to pixel addition processing according to a pixel addition mode described later. Then, compression processing is appropriately performed by the compression / decompression circuit 40 and recording is performed on the recording medium 52.

  In the present embodiment, the AE detection circuit 37 calculates the EV value, the aperture value, and the like that are the brightness of the subject based on the image data, but is not limited to this. For example, an optical sensor or the like that detects the peripheral light amount may be provided, and the calculation may be performed based on the optical sensor output.

  Next, as an operation of the present embodiment, control executed by the CPU 42 will be described with reference to flowcharts shown in FIGS.

  First, the pixel addition mode setting process shown in FIG. 3 will be described. The control shown in FIG. 3 is executed when the user presses the menu / execution button 74 to display a menu screen (not shown) on the LCD 51 and selects “Pixel addition mode setting” from the menu.

  In step 100, a pixel addition mode setting screen 82 as shown in FIG. In the pixel addition mode setting screen 82, as described later, the image quality priority mode for improving the image quality by adding pixels while maintaining the minimum number of pixels set by the user, or the number of pixels while maintaining the minimum image quality level set by the user. It is possible to select one of the pixel number priority modes in which pixels are added so as to increase as much as possible. In the present embodiment, the image quality means an S / N level or a dynamic range, and a case where the lowest image quality level is set to the lowest S / N level will be described as an example.

  In step 102, it is determined whether or not an operation for selecting an image quality priority mode has been performed. If an operation for selecting an image quality priority mode has been performed, the process proceeds to step 104, and an operation for selecting an image quality priority mode has not been performed. If so, the process proceeds to step 106.

  In Step 106, it is determined whether or not the pixel number priority mode is selected. If the pixel number priority mode is selected, the process proceeds to Step 108. If the pixel number priority mode is not selected, the process proceeds to Step 102. Return.

  In step 104, a minimum pixel number setting process is executed. Specifically, a minimum pixel number setting screen 84 as shown in FIG. Then, the user sets any one of the plurality of pixels as the minimum pixel number a. FIG. 7 shows a case where one of 3 million pixels, 6 million pixels, and 12 million pixels can be selected as an example. When the user sets the minimum pixel number a, information indicating that the pixel addition mode is the image quality priority mode and information on the minimum pixel number a set by the user are stored in the EEPROM 38.

  On the other hand, in step 108, a minimum S / N level setting process is executed. Specifically, a minimum S / N level setting screen 86 as shown in FIG. Then, the user is allowed to set one of the plurality of S / N levels as the lowest S / N level b. In FIG. 8, as an example, a case where any of 30 dB, 40 dB, and 50 dB can be selected is shown. When the user sets the lowest S / N level b, information indicating that the pixel addition mode is the pixel number priority mode and information on the lowest S / N level b set by the user are stored in the EEPROM 38.

  Next, pixel addition processing when the image quality priority mode is selected will be described with reference to the flowchart shown in FIG. In this process, in the state where the image quality priority mode is selected, the shutter button 62 is pressed (fully pressed) to execute the shooting process, and the image data of the recorded pixel number X0 of the shot image set by the user is obtained. It is executed when it is temporarily stored in the SDRAM 39.

  In the present embodiment, three types of pixel addition numbers, 0, 2, and 4, that is, no pixel addition, two pixel addition, and four pixel addition will be described as an example. The type is not limited to this.

  First, in step 200, the recorded pixel number X0 and the minimum pixel number a of the photographed image set by the user are read from the EEPROM 38, and it is determined whether or not the recorded pixel number X0 is larger than the minimum pixel number a.

  If the recording pixel number X0 is greater than the minimum pixel number a, the process proceeds to step 202. If the recording pixel number X0 is equal to or less than the minimum pixel number a, the process proceeds to step 214.

  In step 214, it is determined whether or not the recording pixel number X0 is the same as the minimum pixel number a. If the recording pixel number X0 is the same, the process proceeds to step 218 without performing pixel addition, and the recording pixel number X0 is the minimum pixel number. If it is not the same as a, that is, if the recording pixel number X0 is less than the minimum pixel number a, the routine proceeds to step 216.

  In step 216, a warning message indicating that the recording pixel number X0 is less than the minimum pixel number a is displayed on the LCD 51, and then the process proceeds to step 218 without performing pixel addition.

  On the other hand, in step 202, the number of added pixels X1 (= X0 / 4) when the four adjacent pixels are added to form one pixel is calculated.

  In step 204, it is determined whether or not the number of added pixels X1 is equal to or greater than the minimum number of pixels a. If the post-addition pixel number X1 is equal to or greater than the minimum pixel number a, the process proceeds to step 206. If the post-addition pixel number X1 is less than the minimum pixel number a, the process proceeds to step 208.

  In step 206, 4-pixel addition processing is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of four pixels adjacent vertically and horizontally are added to form one pixel, and image data having a recording pixel number X0 / 4 is generated.

  On the other hand, in step 208, the number of added pixels X1 (= X0 / 2) is calculated when two adjacent pixels are added to form one pixel.

  In step 210, it is determined whether or not the number of added pixels X1 is equal to or greater than the minimum number of pixels a. If the post-addition pixel number X1 is equal to or greater than the minimum pixel number a, the process proceeds to step 212. If the post-addition pixel number X1 is less than the minimum pixel number a, the process proceeds to step 218 without pixel addition. Transition.

  In step 212, a two-pixel addition process is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of two adjacent pixels in the vertical or horizontal direction are added to form one pixel, and image data having a recording pixel number X0 / 2 is generated.

  In step 218, the image processing circuit 33 is caused to execute predetermined image processing on the image data. This image processing includes, for example, gain adjustment processing according to the number of added pixels.

  In step 220, the media control unit 41 is instructed to record the image data after the image processing on the recording medium 52.

  As described above, in the image quality priority mode, by performing pixel addition with as many pixels as possible within a range in which the minimum number of pixels set by the user can be maintained, a well-balanced image close to the image quality and resolution expected by the user can be obtained. Can do.

  Next, pixel addition processing when the pixel number priority mode is selected will be described with reference to the flowchart shown in FIG. Note that this processing is performed when the shutter button 62 is pressed (fully pressed) in the state where the pixel number priority mode is selected, and shooting processing is executed. The image data of the recorded pixel number X0 of the captured image set by the user Is stored in the SDRAM 39.

  First, in step 300, the received light amount of the image data of the recording pixel number X0 is calculated. In the present embodiment, as an example, the received light amount is an average received light amount per pixel, and is obtained by dividing the integrated value of the pixel values of all the pixels by the number of pixels.

  In step 302, an expected S / N level is obtained based on the obtained amount of received light. Specifically, for example, information indicating the correspondence between the received light amount (average received light amount per pixel) and the expected S / N level as shown in FIG. 9 is stored in the EEPROM 38 in advance, and this correspondence relationship is expressed. Based on the information, an expected S / N level Y0 corresponding to the amount of received light obtained in step 300 is obtained. The correspondence shown in FIG. 9 may be, for example, a mathematical formula or look-up table data.

  In step 304, it is determined whether or not the expected S / N level Y0 is lower than the lowest S / N level b set by the user. If the predicted S / N level Y0 is lower than the lowest S / N level b, the process proceeds to step 304. If the predicted S / N level Y0 is equal to or higher than the lowest S / N level b, the process proceeds to step 320. To do.

  In step 306, a two-pixel addition process is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of two adjacent pixels in the vertical or horizontal direction are added to form one pixel, and image data having a recording pixel number X0 / 2 is generated.

  In step 308, the expected S / N level of the image data after addition of two pixels is obtained by the same method as in step 302. That is, the average received light amount per pixel is obtained by dividing the integrated value of the pixel values of all pixels by the number of pixels after addition of two pixels, and the expected S / N level Y0 corresponding to this received light amount is shown in FIG. Find based on correspondence.

  In step 310, as in step 304, it is determined whether or not the expected S / N level Y0 is lower than the lowest S / N level b set by the user. If the predicted S / N level Y0 is lower than the lowest S / N level b, the process proceeds to step 312. If the predicted S / N level Y0 is equal to or higher than the lowest S / N level b, the process proceeds to step 320. To do.

  In step 312, 4-pixel addition processing is performed on the image data of the recording pixel number X 0 set by the user. That is, the pixel values of four pixels adjacent vertically and horizontally are added to form one pixel, and image data having a recording pixel number X0 / 4 is generated.

  In step 314, the expected S / N level of the image data after the addition of four pixels is obtained by the same method as in step 302. That is, the average received light amount per pixel is obtained by dividing the integrated value of the pixel values of all pixels by the number of pixels after the addition of four pixels, and the expected S / N level Y0 corresponding to this received light amount is shown in FIG. Find based on correspondence.

  In step 316, as in step 304, it is determined whether or not the expected S / N level Y0 is lower than the lowest S / N level b set by the user. If the predicted S / N level Y0 is lower than the lowest S / N level b, the process proceeds to step 318. If the predicted S / N level Y0 is equal to or higher than the lowest S / N level b, the process proceeds to step 320. To do.

  In step 318, even if four pixels are added, the expected S / N level Y0 is lower than the lowest S / N level b, so a warning message indicating that is displayed on the LCD 51.

  In step 320, the image processing circuit 33 is caused to execute predetermined image processing on the image data. This image processing includes, for example, gain adjustment processing according to the number of added pixels.

  In step 322, the media control unit 41 is instructed to record the image data after the image processing on the recording medium 52.

  In this way, in the pixel number priority mode, by avoiding pixel addition as much as possible within a range in which the minimum S / N level set by the user can be maintained, a well-balanced image close to the image quality and resolution expected by the user. Can be obtained.

  (Second Embodiment)

  Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and the detailed description is abbreviate | omitted.

  In the second embodiment, the configuration of the digital camera is the same as that of the first embodiment, but a case where a so-called ISO auto function is provided will be described. The ISO auto function is a function that brightens the captured image by automatically increasing the ISO sensitivity when the captured image is not properly exposed but too dark, that is, adjusts the gain.

  In the present embodiment, a pixel addition process in the image quality priority mode and a pixel addition process in the pixel number priority mode when the digital camera 60 has an ISO auto function will be described.

  First, pixel addition processing in the image quality priority mode will be described with reference to the flowchart shown in FIG.

  In step 400, the number of added pixels X1 (= X0 / 4) when the four adjacent pixels are added to obtain one pixel is calculated.

  In step 402, it is determined whether or not the number of added pixels X1 is equal to or greater than the minimum number of pixels a. If the post-addition pixel number X1 is equal to or greater than the minimum pixel number a, the process proceeds to step 404. If the post-addition pixel number X1 is less than the minimum pixel number a, the process proceeds to step 408.

  In step 404, ISO auto control for 4-pixel addition is performed. That is, the gain adjustment suitable for adding four pixels is performed.

  In step 406, 4-pixel addition processing is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of four pixels adjacent vertically and horizontally are added to form one pixel, and image data having a recording pixel number X0 / 4 is generated.

  On the other hand, in step 408, the number of added pixels X1 (= X0 / 2) is calculated when two adjacent pixels are added to form one pixel.

  In step 410, it is determined whether or not the number of added pixels X1 is equal to or greater than the minimum number of pixels a. If the post-addition pixel number X1 is equal to or greater than the minimum pixel number a, the process proceeds to step 412. If the post-addition pixel number X1 is less than the minimum pixel number a, the process proceeds to step 416.

  In step 412, ISO auto control for adding two pixels is performed. That is, a gain adjustment suitable for adding two pixels is performed.

  In step 414, two-pixel addition processing is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of two adjacent pixels in the vertical or horizontal direction are added to form one pixel, and image data having a recording pixel number X0 / 2 is generated.

  On the other hand, in step 416, ISO auto control without pixel addition is performed. That is, the gain adjustment suitable for the case where the pixels are not added is performed, and the process proceeds to step 408.

  In step 418, the image processing circuit 33 is caused to execute predetermined image processing on the image data. This image processing includes, for example, gain adjustment processing according to the number of added pixels.

  In step 420, the media control unit 41 is instructed to record the image data after the image processing on the recording medium 52.

  As described above, in the image quality priority mode when the ISO auto function is provided, the pixel addition is performed with the largest possible number of pixels within the range in which the minimum number of pixels set by the user can be maintained, and the ISO auto control suitable for the number of pixel additions. By performing the above, it is possible to obtain a well-balanced image close to the image quality and resolution expected by the user.

  Next, pixel addition processing in the pixel number priority mode will be described with reference to the flowchart shown in FIG.

  First, in step 500, ISO auto control is performed. That is, when the captured image does not have the proper exposure, the ISO sensitivity is automatically and gradually increased, and the gain is adjusted so that the appropriate exposure is obtained.

  In step 502, it is determined whether or not the ISO sensitivity has reached a predetermined maximum sensitivity as a result of the ISO auto control. If the maximum sensitivity is reached, i.e., there is a possibility that the exposure is not adequate even after gain adjustment until the maximum sensitivity is reached, the process proceeds to step 504, and if the maximum sensitivity is not reached, i.e., the maximum sensitivity is reached. If proper exposure is obtained without gain adjustment until sensitivity is reached, the process proceeds to step 516.

  In step 504, it is determined whether or not the captured image after the ISO auto control has a proper exposure. Specifically, the exposure value (EV value) of the photographed image after ISO auto control is calculated based on the image data, and it is determined whether or not this exposure value is within a predetermined appropriate exposure range.

  If the exposure is appropriate, the process proceeds to step 516. If the exposure is not appropriate, the process proceeds to step 506.

  In step 506, 2-pixel addition processing is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of two adjacent pixels in the vertical or horizontal direction are added to form one pixel, and image data having a recording pixel number X0 / 2 is generated.

  In step 508, similarly to step 504, it is determined whether or not the captured image after addition of two pixels has proper exposure. If the exposure is appropriate, the process proceeds to step 516. If the exposure is not appropriate, the process proceeds to step 510.

  In step 510, 4-pixel addition processing is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of four pixels adjacent vertically and horizontally are added to form one pixel, and image data having a recording pixel number X0 / 4 is generated.

  In step 512, as in step 504, it is determined whether or not the photographed image after addition of two pixels has proper exposure. If the exposure is appropriate, the process proceeds to step 516. If the exposure is not appropriate, the process proceeds to step 514.

  In step 514, even if four pixels are added, the exposure is not appropriate, so a warning message indicating that is displayed on the LCD 51.

  In step 516, the image processing circuit 33 is caused to execute predetermined image processing on the image data. This image processing includes, for example, gain adjustment processing according to the number of added pixels.

  In step 518, the media control unit 41 is instructed to record the image data after the image processing on the recording medium 52.

  As described above, in the pixel number priority mode in the case where the ISO auto function is provided, the number of pixels is increased as much as possible even when the ISO exposure reaches the maximum sensitivity by the ISO auto function and the proper exposure is not achieved. Appropriate exposure can be obtained by adding pixels to. As a result, a well-balanced image close to the image quality and resolution expected by the user can be obtained.

  (Third embodiment)

  Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as said each embodiment, and the detailed description is abbreviate | omitted.

  In the third embodiment, the configuration of the digital camera is the same as that of the first embodiment, but a case where so-called auto bracket shooting is performed will be described. In the present embodiment, the auto bracket shooting mode can be selected from a menu screen (not shown) displayed on the LCD 51 as the shooting mode.

  Next, as an operation of the present embodiment, a captured image process executed by the CPU 42 when the auto bracket shooting mode is selected will be described with reference to a flowchart shown in FIG. Note that the processing shown in FIG. 12 is executed when the shutter button 62 is fully pressed to perform shooting processing and image data is stored in the SDRAM 39.

  In step 600, the image processing circuit 33 is instructed to perform image processing without pixel addition, for example, gain adjustment processing, on the image data of the recording pixel number X0 set by the user.

  In step 602, the media control unit 41 is instructed to record the image data after the image processing on the recording medium 52.

  In step 604, two-pixel addition processing is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of two adjacent pixels in the vertical or horizontal direction are added to form one pixel, and image data having a recording pixel number X0 / 2 is generated.

  In step 606, the image processing circuit 33 is instructed to perform image processing for adding two pixels, for example, gain adjustment processing or the like on the image data.

  In step 608, the media control unit 41 is instructed to record the image data after the image processing on the recording medium 52.

  In step 610, 4-pixel addition processing is performed on the image data of the recording pixel number X0 set by the user. That is, the pixel values of four pixels adjacent vertically or horizontally are added to form one pixel, and image data having a recording pixel number X0 / 4 is generated.

  In step 612, the image processing circuit 33 is instructed to perform image processing for 4-pixel addition, such as gain adjustment processing, on the image data.

  In step 614, the media control unit 41 is instructed to record the image data after the image processing on the recording medium 52.

  In this way, in this embodiment, image data is generated from one image data without pixel addition, two-pixel addition, and four-pixel addition, so that images with different noise and resolution can be obtained by one shooting. The user can select a favorite image.

  In each of the above-described embodiments, the case where pixel addition is performed has been described with respect to the case where 2 pixels or 4 pixels are added to the image data of the recording pixel number X0 set by the user. However, the present invention is not limited to this. Pixel addition processing may be performed on a number of image data (RAW image data).

  In each of the above-described embodiments, the case where the pixel data is digitally added to the image data of the photographed image has been described. However, as conventionally known, the pixel 21 is added in an analog manner within the transfer path of the CCD 21 by switching the transfer drive of the CCD 21. It is good also as a structure provided with the function to perform. In this case, either the pixel addition mode for analog pixel addition (first pixel addition mode) or the pixel addition mode for digital pixel addition (second pixel addition mode) is displayed on the LCD 51, for example. It may be selectable from the setting screen. Thereby, pixel addition can be performed in a pixel addition mode according to the user's preference, and user convenience can be improved.

(A) is a front view of the digital camera, and (B) is a rear view of the digital camera. It is a block diagram of a digital camera. It is a flowchart of a pixel addition mode setting process. It is a flowchart of the pixel addition process in the image quality priority mode according to the first embodiment. It is a flowchart of the pixel addition process in the pixel number priority mode according to the first embodiment. It is a figure which shows an example of a pixel addition mode setting screen. It is a figure which shows an example of the minimum pixel number setting screen. It is a figure which shows an example of the minimum S / N level setting screen. It is a figure which shows the correspondence of received light quantity and an estimated S / N level. It is a flowchart of the pixel addition process in the image quality priority mode according to the second embodiment. It is a flowchart of the pixel addition process in the pixel number priority mode according to the second embodiment. It is a flowchart of the pixel addition process in the auto bracket imaging mode according to the third embodiment.

Explanation of symbols

20 Imaging unit 21 Image sensor (imaging element)
24 TG (drive means)
30 Main control unit 42 CPU (setting means, pixel addition means)
60 Digital Camera 62 Shutter Button 64 Strobe Light Emission 66 Lens Opening 68 Optical Finder 70 Operation Unit (Selection Unit)
80 Optical system 82 Pixel addition mode setting screen 84 Minimum pixel number setting screen 86 Level setting screen

Claims (8)

An image sensor that photoelectrically converts light from the subject;
Driving means for driving the imaging element;
A selection means for selecting any of a plurality of predetermined pixel addition modes;
Setting means for setting a pixel addition number of image data of a photographed image photographed by the photographing element according to the selected pixel addition mode;
Pixel addition means for pixel-adding the image data of the captured image according to the set pixel addition number;
An imaging device with The pixel addition mode includes an image quality priority mode that prioritizes the image quality of a captured image, and the selection unit selects any one of a plurality of predetermined minimum pixels when the image quality priority mode is selected. Including a minimum pixel number selection means to select,
The setting means sets the pixel addition number so that the pixel addition number becomes maximum when the image quality priority mode is selected, at or above the selected minimum pixel number. The imaging device described. The pixel addition mode includes a pixel number priority mode that prioritizes the number of pixels of the photographed image, and the selection unit selects from among a plurality of predetermined minimum image quality levels when the pixel number priority mode is selected. Including a minimum image quality level selection means for selecting either,
The setting means, when the pixel number priority mode is selected, sets the pixel addition number so that the pixel addition number becomes maximum at the selected minimum image quality level or higher. The imaging device according to claim 1 or 2.   When the brightness of the photographed image does not reach the appropriate exposure level, the photographed image is gain-adjusted according to the pixel addition number set by the setting means so as to approach the proper exposure level. 3. The photographing apparatus according to claim 2, further comprising adjusting means for increasing the ISO sensitivity. An adjusting means for increasing the ISO sensitivity by adjusting the gain so as to approach the appropriate exposure level when the brightness of the captured image does not reach the appropriate exposure level;
Determining means for determining whether or not the adjusted photographed image has proper exposure when the ISO sensitivity after adjustment by the adjusting means is the highest ISO sensitivity;
Further comprising
4. The photographing apparatus according to claim 1, wherein the setting unit increases the pixel addition number when the determination unit determines that the exposure is not appropriate. 5.   6. The photographing apparatus according to claim 1, further comprising a storage unit that stores a predetermined correspondence relationship between a received light amount of the photographed image and an expected S / N ratio. . The selection means is capable of selecting an auto bracket shooting mode for acquiring a shot image of a plurality of pixels for the same subject,
7. When the auto bracket shooting mode is selected, the pixel addition means records the captured image by sequentially adding pixels with a plurality of predetermined pixel addition numbers. The imaging device according to any one of the above. The imaging element includes a pixel addition function for adding and outputting signal charges of a plurality of pixels in accordance with an instruction from the driving unit,
The selection unit includes a first addition mode in which signal charges of the plurality of pixels are added by a pixel addition function of the imaging element, and a second pixel in which image data of the captured image is added by the pixel addition unit. The photographing apparatus according to any one of claims 1 to 7, wherein either one of the addition modes can be selected.

Images