JP2008072501A - Imaging apparatus, imaging method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus, an imaging method, a program and a recording medium to add peripheral pixels having the same color to a digital image signal and to change the number of added peripheral pixels according to a luminance distribution. <P>SOLUTION: A charge stored in a photodiode is read according to a synchronizing signal to be output from a timing generator, is successively transferred and is output as an analog signal by one pixel through an output amplifier. The analog image signal is converted into the digital image signal at an A/D block 1023, and gamma correction and interpolation processing are performed at a CCD2 signal processing block 1042. A luminance signal is calculated from processed RGB data and the number of added peripheral pixels is changed according to a calculated luminance level. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, an imaging method, a program, and a recording medium that generate an electronic image.

  While various digital cameras are being developed, a method in which the developer classifies according to the luminance level, such as a pixel addition method, has been created with the greatest goal of improving performance.

  In the conventional pixel addition method, even if it is used for monitoring and moving images, it is VGA size (640 x 480) and does not use all pixels, so two pixels are added to the entire screen in hardware in the image sensor, and four pixels are added. , 9 pixel addition processing has been performed.

  In moving image imaging using a high-quality color solid-state imaging device, thinning readout as represented by vertical thinning is common.

  For example, in Patent Document 1, the pixel area of a high-quality color solid-state imaging device is divided into units for pixel mixing, and the total number of pixels of the same color is mixed in each area 16 to 19, thereby increasing the pixel utilization rate to 100%. At the same time, an imaging apparatus that can significantly suppress aliasing noise for reduction of high-frequency video signals by the spatial LPF effect of area pixel mixing has been proposed.

  Patent Document 2 proposes an imaging device that measures the total amount of blackout and whiteout pixels in the imaging screen from the luminance distribution data and controls exposure so that blackout and whiteout are reduced. ing.

In Patent Document 3, first, an image of each field is monitored by monitoring, an AE evaluation value is calculated from the result, and as a result, exposure field data is read if the luminance is low, and the first and second field data are read. In comparison, an imaging apparatus that determines whether or not a subject is moving is proposed based on the comparison result.
Japanese Patent Laid-Open No. 2004-312140 Japanese Patent Laid-Open No. 3-254581 JP 2004-235901 A

  However, Patent Document 1 has a problem that not only the high-frequency video signal is returned to the low frequency due to resampling, but also the effective sensitivity is significantly reduced by discarding the pixel signal.

  Further, in Patent Document 2, if pixels are added to the entire screen, blackout on the low luminance side is eliminated, but pixels are added on the high luminance side, so that there is a possibility that whiteout occurs.

  In addition, in order to use pixel addition in a still image, a technique is used in which two images are taken and added together with a time difference, but when two images are used, the subject is dynamic. Then, it is necessary to perform complex image processing according to the movement of the subject and add the two images together.

  Therefore, in the present invention, an image pickup apparatus, an image pickup method, a program, and a recording medium that change the number of added pixels of the peripheral pixels in accordance with the luminance distribution by adding peripheral pixels of the same color to the digital video signal. The purpose is to provide.

  In order to achieve the above object, an invention according to claim 1 is directed to an imaging device that converts an optical signal of a subject image into an electrical signal by photoelectric conversion, and a video signal from the imaging device is converted from an analog video signal to a digital signal. A / D conversion means for converting to a video signal, pixel addition means for adding peripheral pixels of the same color to the digital video signal, and the number of added pixels of the peripheral pixels to be added by the pixel addition means, The image pickup apparatus includes an addition pixel number changing unit that changes in accordance with the luminance distribution.

  According to a second aspect of the present invention, in the imaging apparatus according to the first aspect, the addition pixel number changing unit changes the addition pixel number for each pixel.

  According to a third aspect of the present invention, in the imaging device according to the first aspect, the addition pixel number changing unit changes the number of addition pixels for each block-divided region.

  According to a fourth aspect of the present invention, in the imaging device according to the first aspect, a threshold value is set for the luminance, and the pixel adding unit is configured to set the luminance when the luminance is lower than the threshold value. Pixel addition is performed.

  According to a fifth aspect of the present invention, in the imaging apparatus according to the first aspect, the luminance distribution is calculated from an RGB integrated value of each block obtained by dividing the captured image into a plurality of blocks. To do.

  According to a sixth aspect of the present invention, in the imaging device according to the first aspect, the luminance distribution is calculated from the luminance signal obtained by converting the video signal into a luminance signal and a color difference signal. And

  According to a seventh aspect of the present invention, in the imaging apparatus according to the first aspect, the luminance distribution is calculated from a luminance signal of the reduced image by creating a reduced image for the captured image.

  According to an eighth aspect of the present invention, there is provided a photoelectric conversion step of converting an optical signal of a subject into an electric signal using an image sensor, and an A for converting a video signal from the image sensor from an analog video signal to a digital video signal. The / D conversion step, the pixel addition step of adding peripheral pixels of the same color to the digital video signal, and the number of added pixels of the peripheral pixels added by the pixel addition step are changed according to the luminance distribution And an addition pixel number changing step.

  According to a ninth aspect of the present invention, in the imaging method according to the eighth aspect, the addition pixel number changing step changes the addition pixel number for each pixel.

  According to a tenth aspect of the present invention, in the imaging method according to the eighth aspect, the addition pixel number changing step changes the addition pixel number for each block-divided region.

  According to an eleventh aspect of the present invention, in the imaging method according to the eighth aspect, a threshold value is set for the luminance, and the pixel adding step is performed when the luminance is a value lower than the threshold value. Pixel addition is performed.

  The invention according to claim 12 is the imaging method according to claim 8, further comprising the step of dividing the captured image into a plurality of blocks and calculating the luminance distribution from RGB integrated values of the respective blocks. Features.

  The invention described in claim 13 includes the step of converting the video signal into a luminance signal and a color difference signal in the imaging method according to claim 8, and calculating the luminance distribution from the converted luminance signal. It is characterized by.

  According to a fourteenth aspect of the present invention, in the imaging method according to the eighth aspect, the method includes a step of creating a reduced image from the captured image and calculating the luminance distribution from a luminance signal of the reduced image. .

  According to a fifteenth aspect of the present invention, there is provided a photoelectric conversion process for converting an optical signal of a subject into an electrical signal by using an image sensor, and an A for converting a video signal from the image sensor from an analog video signal to a digital video signal. / D conversion processing, pixel addition processing for adding peripheral pixels of the same color to the digital video signal, and the number of added pixels of the peripheral pixels added by the pixel addition processing are changed according to the luminance distribution It is a program that causes a computer to execute the added pixel number changing process.

  According to a sixteenth aspect of the present invention, in the program according to the fifteenth aspect, the addition pixel number changing process causes a computer to execute a process of changing the addition pixel number for each pixel.

  According to a seventeenth aspect of the present invention, in the program according to the fifteenth aspect, the addition pixel number changing process causes a computer to execute a process of changing the addition pixel number for each block-divided region. .

  According to an eighteenth aspect of the present invention, in the program according to the fifteenth aspect, a threshold value is set for luminance, and the pixel addition processing is performed when the luminance is a value lower than the threshold value. It is characterized by causing a computer to execute the processing to be performed.

  According to a nineteenth aspect of the present invention, in the program according to the fifteenth aspect, the captured image is divided into a plurality of blocks, and the computer is caused to execute a process of calculating the luminance distribution from the RGB integrated values of the respective blocks. It is characterized by that.

  According to a twentieth aspect of the invention, in the program according to the fifteenth aspect, the video signal is converted into a luminance signal and a color difference signal, and a process of calculating the luminance distribution from the converted luminance signal is executed on a computer. It is characterized by making it.

  According to a twenty-first aspect of the present invention, in the program according to the fifteenth aspect, a reduced image is created for a captured image, and the computer is caused to execute processing for calculating the luminance distribution from a luminance signal of the reduced image. And

  The invention described in claim 22 is a computer-readable recording medium in which the program according to any one of claims 15 to 21 is recorded.

  According to the present invention, an image pickup apparatus, an image pickup method, a program, and a recording medium that change the number of added pixels of the peripheral pixels according to a luminance distribution by adding peripheral pixels of the same color to a digital video signal. Can be provided.

  In this embodiment, an image pickup apparatus that uses a single photographed image to achieve high sensitivity while preventing blackout and whiteout, and that does not require a hardware image stabilization function using a general image pickup device is provided. The purpose is to do.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  First, the operation of the digital camera will be described with reference to FIGS. FIG. 1 shows a simple external view of a digital camera used in the present embodiment, FIG. 2 shows a detailed external view of the digital camera used in the present embodiment, and FIG. 3 shows the digital camera used in the present embodiment. A block diagram of the control system is shown.

  1, 2, and 3, the strobe light emitting unit 3 and the strobe circuit 114 are devices that compensate for the amount of light when light such as natural light is insufficient. When shooting in a dark place or when the subject is dark, a digital flash camera processor 104, which will be described later, transmits a strobe light emission signal to a strobe circuit 114, and the strobe circuit 114 emits the strobe light emitting unit 3 to brighten the subject.

  The distance measuring unit 5 is a device that measures the distance between the camera and the subject. Currently, a digital camera uses a CCD-AF method in which the contrast of an image formed on an image sensor (CCD) is detected, and the lens is moved to a position with the highest contrast to adjust the focus. However, the CCD-AF method has a problem that the focusing operation is slow because the lens is moved little by little to search for contrast. Therefore, the distance measurement unit 5 is always used to obtain distance information with respect to the subject, and the lens is moved from the distance information at a stretch to speed up the focusing operation.

  The lens barrel unit 7 includes a zoom lens 701 that captures an optical image of a subject, a zoom optical system 71 including a zoom drive motor 711, a focus optical system 72 including a focus lens 702 and a focus drive motor 712, an aperture 703, and an aperture motor 713. A diaphragm unit 73, a mechanical shutter 704, a mechanical shutter unit 74 including a mechanical shutter motor 714, and a motor driver 750 for driving each motor are provided. The motor driver 750 is driven and controlled by a drive command from a CPU block 1043 in the digital still camera processor 104 to be described later, based on an input from the remote control light receiving unit 6 and an operation input from the operation unit key unit (SW1 to SW13). . The ROM 108 stores a control program and parameters for control described in a code readable by the CPU block 1043. When the power of the digital camera is turned on, the program is loaded into a main memory (not shown), and the CPU block 1043 controls the operation of each unit according to the program and temporarily stores data necessary for the control. The image data is stored in the RAM 107 and a local SRAM 1044 in the digital still camera processor 104 described later. By using a rewritable flash ROM for the ROM 108, it is possible to change the control program and parameters for control, and the function can be easily upgraded.

  The CCD 101 is a solid-state imaging device for photoelectrically converting an optical image. The F / E (front end) -IC 102 is a CDS 102-1 that performs correlated double sampling for removing image noise, an AGC 1022 that performs gain adjustment, and a digital signal. A vertical synchronization signal (hereinafter referred to as VD) and horizontal synchronization signal (hereinafter referred to as HD) are supplied from the A / D 1023 and the CCD1 control block 1041 that perform conversion, and the CCD 101 controlled by the CPU block 1043, and It has a TG 1024 that generates a drive timing signal for the F / E-IC 102.

  The digital still camera processor 104 performs white balance setting and gamma setting on the output data of the F / E-IC 102 from the CCD 101, and as described above, the CCD1 control block 1041 that supplies VD signal and HD signal, and filtering processing. , CCD2 control block 1042 for converting to luminance data / color difference data, CPU block 1043 for controlling the operation of each part of the device, Local SRAM 1044 for temporarily storing the data necessary for the control, a personal computer, etc. USB block 1045 for USB communication with external devices, serial block 1046 for serial communication with external devices such as personal computers, JPEG CODEC block 1047 for JPEG compression / decompression, and image data size expansion / interpolation processing RESIZE block 1048 to be reduced, TV signal display block 1049 for converting image data into a video signal for display on an external display device such as a liquid crystal monitor or a TV, and a memory card for controlling a memory card for recording captured image data A controller block 1040 is included.

  The SDRAM 103 temporarily stores image data when the digital still camera processor 104 performs various processes on the image data. The stored image data is, for example, “RAW-RGB image data” in which the CCD 101 signal processing block 1041 performs white balance setting and gamma setting from the CCD 101 via the F / E-IC 102. “YUV image data” in which luminance data / color difference data conversion has been performed in the CCD2 control block 1042, JPEG compressed “JPEG image data” in the JPEG CODEC block 1047, and the like. The memory card throttle 121 is a throttle for mounting a removable memory card.

  The built-in memory 120 is a memory for allowing the captured image data to be stored even when the memory card 1211 is not attached to the memory card throttle 1210 described above. The LCD driver 117 is a drive circuit that drives the LCD monitor 10 to be described later, and has a function of converting the video signal output from the TV signal display block 1049 into a signal for display on the LCD monitor 10. The LCD monitor 10 is a monitor for monitoring the state of a subject before photographing, confirming a photographed image, displaying image data recorded in a memory card or the built-in memory 120 described above, and the like.

  The video AMP 118 is an amplifier for converting the impedance of the video signal output from the TV signal display block 1049 to 75Ω, and the video jack 119 is a jack for connecting to an external display device such as a TV. The USB connector 122 is a connector for performing USB connection with an external device such as a personal computer.

  The serial driver circuit 1231 is a circuit for converting the output signal of the serial block 1046 described above to perform serial communication with an external device such as a personal computer. The RS-232C connector is serially connected to an external device such as a personal computer. This is a connector for connection.

  The SUB-CPU 109 is a CPU in which ROM / RAM is built in one chip, and outputs the output signals of the operation key units (SW1 to SW22) and the remote control light receiving unit 6 to the CPU block 1043 described above as user operation information. The state of the camera output from the CPU block 1043 is converted into control signals for the sub LCD 1, AF LED 8, strobe LED 9, and buzzer 113, which will be described later, and output. The sub LCD 1 is a display unit for displaying, for example, the number of shootable images, and the LCD driver 111 is a drive circuit for driving the sub LCD 1 described above based on the output signal of the SUB-CPU 109 described above.

  The AF LED 8 is an LED for displaying an in-focus state at the time of photographing, and the strobe LED 9 is an LED for representing a strobe charging state. The AF LED 8 and the strobe LED 9 may be used for another display application such as when a memory card is being accessed. The operation key units (SW1 to SW22) are key circuits operated by the user, and the remote control light receiving unit 6 is a signal reception unit of the remote control transmitter operated by the user.

  The audio recording unit 115 includes a microphone 1153 to which a user inputs an audio signal, a microphone AMP 1152 that amplifies the input audio signal, and an audio recording circuit 1153 that records the amplified audio signal. The audio reproduction unit 116 converts the recorded audio signal into a signal that can be output from the speaker 1163, amplifies the converted audio signal, an audio AMP 1162 for driving the speaker 1163, and outputs an audio signal A speaker 1163 is included.

  The internal structure and functions of the digital camera of the present embodiment configured as described above will be described in detail below with reference to FIGS.

(CCD sensor structure)
The structure of the CCD sensor will be described. FIG. 4 is a schematic diagram of an interline CCD sensor used for a digital camera or the like in the present embodiment. A photodiode that accumulates charges according to the amount of incident light and converts an optical signal into an electrical signal, a vertical transfer path that receives charges from the photodiode and sequentially transfers them in the vertical direction, and sequentially transfers charges from the vertical transfer paths in the horizontal direction It consists of a horizontal transfer path for transfer and an output amplifier for amplifying the output signal of the horizontal transfer path.

  On the imaging device, photodiodes are regularly arranged in a two-dimensional manner, and one photodiode corresponds to one pixel. One photodiode is covered with one color filter. In the primary color CCD sensor, RGB color filters are arranged in a color arrangement called a Bayer arrangement as shown in FIG. In the photodiode, light of a color corresponding to the color filter is accumulated as a charge.

(Signal flow)
The charge accumulated in the photodiode is read out to the vertical transfer path in accordance with the synchronization signal output from the timing generator. At this time, there are two types of methods for reading out charges to the vertical transfer path, one for simultaneously reading the charges of all the photodiodes and one for reading several times.

  This depends on the CCD device, and the former is called a progressive method and the latter is called an interlace method. When the number of pixels of the image sensor increases, it is difficult to provide a photodiode for a vertical transfer path that receives the charges of all the pixels. By providing, the number of photodiodes is reduced.

  The charges read to the vertical transfer path are sequentially transferred to the horizontal transfer path in the vertical direction, sequentially transferred in the horizontal direction on the horizontal transfer path, and output as an analog signal pixel by pixel through the output amplifier. The output analog signal is subjected to image noise removal and sampling in the CDS block 1021 of the F / E-IC 102, gain multiplication in the AGC block 1022, and conversion from an analog signal to a digital signal in the A / D block 1023. Is done. At this stage, the image data is not processed and is called RAW data. Digital signal data is stored in the SDRAM 103 by the CCD1 signal processing block 1041, and image processing is performed by the CCD2 signal processing block 1042.

  As image processing, gamma correction and interpolation processing are performed. In general, an image display device (for example, an LCD) has a non-linear characteristic with respect to an input, and therefore performs gamma correction to generate an input signal that makes the output linear. In addition, since RAW data has only one color information per pixel, the interpolation process interpolates two missing colors using peripheral pixels, and information on three colors R, G, and B per pixel. I have it.

(About luminance distribution calculation)
<Calculated from RGB>
For the acquisition of luminance information, RGB data is read from the SDRAM 103 in the CPU block 1043 for the RGB data subjected to gamma correction and interpolation processing on the RAW data, and the luminance is calculated using the following calculation formula: Calculate the signal.

  Assuming that the luminance signal is Y, the unit for calculating Y = 0.299xR + 0.587xG + 0.114xB may be performed for all pixels, or the entire screen is divided into a plurality of blocks and R, The average value of G and B may be calculated, and the luminance signal may be calculated by applying it to the above equation. A histogram with the horizontal axis luminance value and the vertical axis frequency is created for the calculated luminance signal to obtain a luminance distribution.

<Calculated from luminance signal>
Since a JPEG image is created from a luminance signal Y and color difference signals U and V, a digital camera generally has a hard logic for converting RGB data into YUV data as image processing. In the configuration example of this embodiment, this function is provided in the CCD2 signal processing block 1042, and in the case of such a hard logic, the processing speed is fast and more efficient than software calculation. Therefore, after the entire screen is converted from RGB data to YUV data, a histogram of the horizontal axis luminance value and the vertical axis frequency is created for the Y (luminance value) data to obtain a luminance distribution.

<Calculated from reduced image (rec review image)>
In the case of the interlaced CCD, an image can be created as a thinned image if there are RG and GB lines without reading out all the pixels. This is generally called a reduced image (rec review image), etc., and several fields (one image framed first) acquired on the LCD screen during image capture, image processing, saving to a memory card, etc. The area that is divided and read is called a field), and an image is created and displayed to inform the user of the image of the captured image.

  The luminance information can be obtained from all pixels or from such a REC review image. However, when obtaining from all pixels, the information is more detailed, but the amount of information is large and the calculation load is large. There is a problem of increasing. When the REC review image is used, the acquisition of luminance information can be started before capturing all the pixels, information is obtained at an early stage, and the calculation load is small. In addition, since the result calculated from all pixels and the result calculated from the REC review image are not so different, the effect of acquiring luminance information using the REC review image is great.

(About pixel addition method)
<Adding in units of one pixel>
A method of performing pixel addition using peripheral pixels in this embodiment will be described. FIG. 5 shows an example in which a pixel to be subjected to pixel addition and its surrounding pixels are extracted in a 5 × 5 range. If the target pixel is a hatched pixel, there are eight pixels of the same color surrounding the target pixel. As a pixel addition method, there are a case where a peripheral pixel is simply added to a target pixel as it is, and a case where a ratio is added to the target pixel and the peripheral pixel.

<Simple addition>
The simple addition will be described. When the peripheral pixels are numbered as shown in FIG.
Two pixel addition is the pixel of interest + (I),
Three pixel addition is performed by adding the target pixel + (I) + (II),
4-pixel addition is the target pixel + (I) + (II) + (III),
The 5-pixel addition is performed by adding a target pixel + (I) + (II) + (III) + (IV),
6 pixel addition is the target pixel + (I) + (II) + (III) + (IV) + (V),
The 7-pixel addition is performed by adding the target pixel + (I) + (II) + (III) + (IV) + (V) + (VI),
The 8-pixel addition is performed by adding the target pixel + (I) + (II) + (III) + (IV) + (V) + (VI) + (VII),
Nine-pixel addition is performed by adding the target pixel + (I) + (II) + (III) + (IV) + (V) + (VI) + (VII) + (VIII),
It becomes.
<Ratio addition>
To explain the ratio addition,
Two pixel addition is the target pixel + I × α,
3-pixel addition is the target pixel + (I + II) × α,
4-pixel addition is the target pixel + (I + II + III) × α,
5-pixel addition is the target pixel + (I + II + III + IV) × α,
6 pixel addition is the target pixel + (I + II + III + IV) × α + V × β,
7 pixel addition is the target pixel + (I + II + III + IV) × α + (V + VI) × β,
Eight pixel addition is the target pixel + (I + II + III + IV) × α + (V + VI + VII) × β,
9 pixel addition is the target pixel + (I + II + III + IV) × α + (V + VI + VII + VIII) × β,
It becomes. Here, α and β take arbitrary values from 0 to 1.

(Pixel addition flow)
Next, the pixel addition flow will be described with reference to FIG. FIG. 6 shows a flow when the number of added pixels is changed in units of pixels.

  First, luminance distribution information is acquired for the captured image by the above method (step S101), and the luminance value of the target pixel is calculated (step S102).

  Next, a threshold value is set in advance on the low luminance side of the luminance value, and whether or not the calculated luminance value of the target pixel is smaller than the threshold value is compared (step S103). If the luminance value of the target pixel is lower than the threshold value (step S103 / YES), the number of added pixels is determined according to the luminance level of the number of target pixels (step S104), and the addition process is performed (step S105). ). When it is higher than the threshold value (step S103 / NO), pixel addition is not performed. When performing the addition process, the determined number of added pixels is applied to all the pixels in the block. Thereafter, it is identified whether or not the processing for all the pixels has been completed (step S107). If all the pixels have not been completed (step S107 / NO), the processing is repeated from the calculation of the luminance value of the target pixel (step S102). When all the pixels are finished, all the processes are finished (step S107 / YES).

(Determining the number of added pixels according to the luminance level)
FIG. 7 is a diagram showing a method of determining the number of added pixels according to the luminance level, and is a histogram in which the horizontal axis represents the luminance value and the vertical axis represents the frequency. As the horizontal axis goes to the right, the luminance value increases, and as the vertical axis goes upward, the frequency increases.

  Now, pixel addition is performed when the luminance value of the target pixel is smaller than the threshold value (th), but the number of added pixels is changed depending on the level of the luminance value (y) of the target pixel.

  In FIG. 6, depending on the level of the luminance value (y) of the target pixel, two pixels are added when b <y <th, three pixels are added when a <y <b, and 0 <y <a. In this case, 4-pixel addition is performed.

<Change the number of pixels to add in block units>
In the above description, the number of added pixels is determined in units of pixels. Next, a description will be given of a case in which the number of added pixels is determined in units of blocks. FIG. 8 shows a flow when the number of added pixels is changed in units of blocks.

  Block generation is performed by dividing the entire screen into m × n regions by dividing the screen into m equal parts in the vertical direction and n equal parts in the horizontal direction (m and n are natural numbers, respectively).

  First, luminance distribution information is acquired for the captured image by the above method (step S201), and the average luminance value (ya) of the block of interest is calculated (step S202).

  Next, a comparison is made as to whether or not the calculated luminance value average of the target block is smaller than the threshold value with respect to the threshold value set in advance on the low luminance side of the luminance value (step S203), and the luminance value average of the target pixel is determined. Is lower than the threshold value (step S203 / YES), the number of added pixels is determined according to the average luminance value level of the block of interest (step S204), and the addition process is performed (step S205). When it is higher than the threshold value, pixel addition is not performed (step S203 / NO). After performing the pixel addition process, it is recognized whether the pixel addition process has been completed for all the pixels in the block (step S207). If all the pixel processes have been completed, all the processes are terminated (step S207). / YES). If all the pixels have not been completed (step S207 / NO), the process is repeated from the average luminance value calculation of the block of interest (step S202). In addition, the method for determining the number of added pixels is the same as that for the pixel unit, and thus description thereof is omitted.

  In the present embodiment, by changing the number of added pixels of peripheral pixels according to the luminance, it is possible to prevent black crushing without brightening the entire captured image. In addition, pixel addition can be performed without using a special image sensor, and high sensitivity can be achieved to prevent camera shake and subject blur, so there is no need to load the camera shake correction function in hardware. Even good images can be taken.

It is a succinct external view showing a digital camera in the present embodiment. It is a detailed external view showing a digital camera in the present embodiment. It is a block diagram which shows the control system of the digital camera in this embodiment. It is a schematic diagram which shows the structure of the interline type CCD sensor used for the digital camera etc. in this embodiment. It is a figure which shows description of pixel number addition in this embodiment. It is a figure which shows the flowchart at the time of changing the addition pixel number per pixel in this embodiment. It is a figure which shows the determination method of the addition pixel number according to a luminance level in this embodiment. It is a figure which shows the flowchart of the pixel addition by block division in this embodiment.

Explanation of symbols

1 Sub LCD
2 Release button 3 Strobe light emitting unit 4 Shooting / playback switching dial 5 Ranging unit 6 Remote control light receiving unit 7 Lens barrel unit 71 ZOOM optical system 701 ZOOM lens 711 ZOOM motor 72 FOUCAS optical system 702 FOUCAS lens 712 FOUCAS unit 73 FOUCAS unit 73 713 Aperture motor 74 Mechanical shutter unit 704 Mechanical shutter 714 Mechanical shutter motor 8 AFLED
9 Strobe LED
DESCRIPTION OF SYMBOLS 10 LCD monitor 11 Optical finder 12 Zoom button 13 Power switch 14 Operation part 15 Self-timer 16 Menu switch 17 OK switch 18 Image confirmation switch 19 Macro switch 20 Strobe switch 21 Right switch 22 Display switch 101 CCD
102 F / E-IC
1021 CDS
1022 AGC
1023 A / D
1024 TG
103 SDRAM
104 Digital Still Camera Processor 1040 Memory Card Controller Block 1041 CCD1 Signal Processing Block 1042 CCD2 Signal Processing Block 1043 CPU Block 1044 Local SRAM
1045 USB block 1046 Serial block 1047 JPEGCODEC block 1048 RESIZE block 1049 TV signal display block 107 RAM
108 ROM
109 SUB-CPU
111 LCD Driver 113 Buzzer 114 Strobe Circuit 1151 Audio Recording Circuit 1152 Microphone AMP
1153 Microphone 1161 Audio reproduction circuit 1162 Audio AMP
1163 Speaker 115 Audio recording unit 116 Audio reproduction unit 117 LCD driver 118 Video AMP
119 Video jack 120 Internal memory 1210 Memory card throttle 1211 Memory card 122 USB connector 1231 Serial driver circuit 1232 RS-232c connector

Claims (22)

An image sensor that converts an optical signal of a subject image into an electrical signal by photoelectric conversion;
A / D conversion means for converting the video signal from the image sensor from an analog video signal to a digital video signal;
Pixel addition means for adding peripheral pixels of the same color to the digital video signal;
An image pickup apparatus comprising: an addition pixel number changing unit that changes the number of added pixels of the peripheral pixels added by the pixel addition unit according to a luminance distribution.   The imaging apparatus according to claim 1, wherein the addition pixel number changing unit changes the addition pixel number for each pixel.   The image pickup apparatus according to claim 1, wherein the addition pixel number changing unit changes the addition pixel number for each block-divided region.   The imaging apparatus according to claim 1, wherein a threshold value is set for luminance, and the pixel addition unit performs pixel addition when the luminance is lower than the threshold value.   The imaging apparatus according to claim 1, wherein the luminance distribution is calculated from an RGB integrated value of each block obtained by dividing the captured image into a plurality of blocks.   The imaging apparatus according to claim 1, wherein the luminance distribution is calculated from the luminance signal after the video signal is converted into a luminance signal and a color difference signal.   The imaging apparatus according to claim 1, wherein the luminance distribution is calculated from a luminance signal of the reduced image by creating a reduced image with respect to the captured image. A photoelectric conversion step of converting an optical signal of a subject into an electrical signal using an image sensor;
An A / D conversion step of converting the video signal from the image sensor from an analog video signal to a digital video signal;
A pixel addition step of adding peripheral pixels of the same color to the digital video signal;
An imaging method, comprising: an addition pixel number changing step of changing an addition pixel number of the peripheral pixels to be added in the pixel addition step according to a luminance distribution.   The imaging method according to claim 8, wherein the adding pixel number changing step changes the adding pixel number for each pixel.   The imaging method according to claim 8, wherein in the addition pixel number changing step, the addition pixel number is changed for each block-divided region.   The imaging method according to claim 8, wherein a threshold value is set for luminance, and the pixel addition step performs pixel addition when the luminance is a value lower than the threshold value.   The imaging method according to claim 8, further comprising a step of dividing the captured image into a plurality of blocks and calculating the luminance distribution from RGB integrated values of the respective blocks.   9. The imaging method according to claim 8, further comprising a step of converting the video signal into a luminance signal and a color difference signal, and calculating the luminance distribution from the converted luminance signal.   The imaging method according to claim 8, further comprising a step of creating a reduced image for the captured image and calculating the luminance distribution from a luminance signal of the reduced image. Photoelectric conversion processing that converts an optical signal of a subject into an electrical signal using an image sensor;
A / D conversion processing for converting the video signal of the image sensor from an analog video signal to a digital video signal;
Pixel addition processing for adding peripheral pixels of the same color to the digital video signal;
A program causing a computer to execute an addition pixel number changing process of changing the number of added pixels of the surrounding pixels according to a luminance distribution by the pixel addition process.   16. The program according to claim 15, wherein the addition pixel number changing process causes a computer to execute a process of changing the addition pixel number for each pixel.   The program according to claim 15, wherein the addition pixel number changing process causes a computer to execute a process of changing the addition pixel number for each block-divided area.   The threshold value is set for luminance, and the pixel addition processing causes a computer to execute pixel addition processing when the luminance is lower than the threshold value. program.   The program according to claim 15, wherein the captured image is divided into a plurality of blocks, and the computer executes a process of calculating the luminance distribution from the RGB integrated values of the respective blocks.   16. The program according to claim 15, further comprising: causing the computer to execute a process of converting the video signal into a luminance signal and a color difference signal and calculating the luminance distribution from the converted luminance signal.   The program according to claim 15, wherein the computer executes a process of creating a reduced image from the captured image and calculating the luminance distribution from a luminance signal of the reduced image.   The computer-readable recording medium which recorded the program of any one of Claim 15 to 21.

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