JP2006197222A - Photographing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographing device which can perform energy-conservation measures according to a photographing scene. <P>SOLUTION: A photographing device comprises a photographing means; a driving control signal generation means for generating a control signal which controls the drive of the photographing means; a reference signal generation means for generating a reference signal used by the driving control signal generation means; a reference signal control means for controlling an operation of the reference signal generation means; and an exposure control means for performing an exposure control of the photographing means based on an image signal. The reference signal control means controls the operation of the reference signal generation means so that the frequency of the reference signal generated by the reference signal generation means may be changed, based on an exposure control value set by the exposure control means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus capable of changing a pixel transfer clock of an imaging element according to a shooting scene.

  In recent years, as the performance of imaging devices such as electronic cameras and digital video cameras has improved, the performance of imaging devices represented by CCD (Charge Coupled Device) is also required to have high resolution and high definition. It has become. For example, the image pickup device when the electronic camera was first commercialized was mainly VGA (Video Graphics Array; number of pixels = 640 × 480 pixels), but recently, SXGA (Super Extended Graphics Array; pixels). Number = 1280 × 1024 pixels) and 5 million pixel class image sensors.

  On the other hand, an image sensor with a high pixel density increases the frequency of the drive signal so that it can be used for high-speed driving. However, if the drive signal is increased in speed, the power consumption increases, so the battery will run relatively quickly. It will be consumed, greatly affecting the number of shots and usage time.

  In this way, with the higher performance of imaging devices, the increase in the number of pixels in the imaging device is accelerating, but on the other hand, it causes an increase in power consumption, which greatly affects the number of shots. It is necessary to reduce the effect. Various techniques for energy saving measures for increasing power consumption have been studied in the field of imaging devices.

Specifically, there is a video camera device technology (for example, Patent Document 1) that automatically reduces the frame rate when the subject's illuminance decreases to realize long-time accumulation and increase sensitivity. As described above, a technique for reducing the power consumption of the image pickup apparatus to save energy in order to secure the number of images to be taken against the increase in power consumption has been studied.
JP 2000-23003 (see paragraph 0019, etc.)

  By the way, the frame rate of a digital camera may greatly affect operability and depictability depending on the shooting scene. For example, when shooting a subject that moves rapidly, such as a sports scene, a high shutter speed is required. In such shooting, if the frame rate is slow, the display image cannot follow the movement of the subject. As a result, it is difficult to determine the composition and the photo opportunity is missed.

  On the other hand, when shooting a stationary object or shooting a moving subject for a long time to obtain an afterimage effect, a fast frame rate is not necessary. At the same time, power consumption can be reduced.

In this way, depending on the shooting scene, it is necessary to shoot without reducing the frame rate, or on the other hand, it may be possible to obtain a good quality picture by reducing the frame rate. A digital camera capable of changing the frame rate setting has been desired.
The technique disclosed in Patent Document 1 described above realizes high sensitivity by changing the frame rate setting by detecting the illuminance of the subject. However, an imaging apparatus capable of setting the frame rate according to the shooting scene is provided. There was no suggestion.

  The present invention has been made in view of the above problems, and an object thereof is to provide an imaging device capable of changing the frame rate setting according to the shooting scene without incurring complexity and high cost of the device due to an increase in the number of parts. To do. Specifically, when shooting a fast moving subject, set a frame rate that supports high-speed shooting, and for shooting that does not require a fast shutter speed, reduce the pixel transfer clock of the image sensor to reduce power consumption. An object of the present invention is to provide an imaging apparatus that can efficiently and efficiently save energy.

  The above object is achieved by the invention according to any one of claims 1 to 3.

(Claim 1)
Imaging means for photoelectrically converting a subject light image to generate an image signal;
Drive control signal generating means for generating a control signal for controlling driving of the imaging means;
Reference signal generating means for generating a reference signal used in the drive control signal generating means;
Reference signal control means for controlling the operation of the reference signal generation means;
Exposure control means for performing exposure control of the imaging means based on the image signal, the reference signal control means,
Based on the exposure control value set by the exposure control means,
An image pickup apparatus that controls the operation of the reference signal generation means so that the frequency of the reference signal generated by the reference signal generation means varies.

(Claim 2)
The reference signal control means includes
Having a preset reference exposure control value,
The exposure control value set by the exposure control means is compared with the reference exposure control value, and control is performed so as to change the frequency of the reference signal generated by the reference signal generating means based on the comparison result. The imaging apparatus according to claim 1.

(Claim 3)
Exposure control mode selection means for selecting processing contents in the exposure control means;
The reference signal control means operates the reference signal generation means so that the frequency of the reference signal generated by the reference signal generation means varies based on the exposure control value selected by the exposure control mode selection means. The imaging apparatus according to claim 1, wherein the imaging apparatus is controlled.

  In the present invention, the reference signal control means has a preset reference exposure control value, compares the exposure control value set by the exposure control means at the time of shooting with the reference exposure control value, and based on the comparison result. Thus, the setting of the frequency of the reference signal generated by the reference signal generating means can be changed. That is, when the exposure control value at the time of shooting is lower than the threshold value, the frequency of the drive control signal for controlling the driving of the image pickup means can be reduced, and the power consumption of the CCD is reduced in shooting at a low shutter speed. It is possible to perform shooting with a good finish.

  As described above, according to the present invention, when performing shooting that does not require a fast frame rate, such as shooting of a stationary object or shooting of a moving subject for a long time to obtain an afterimage effect, the frame rate is decreased. It can reduce power consumption and perform energy-saving shooting. Further, when shooting a moving subject such as a sports scene, the original frame rate is maintained, so that shooting at a high shutter speed can be performed stably.

  As a specific embodiment of the imaging apparatus according to the present invention, a digital camera is typical, but a mobile phone with a camera, a digital video camera, and the like are also included.

  The appearance of a digital camera that is one of the representative embodiments of the imaging apparatus according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1A is a front view of a digital camera 1 according to the present invention, and FIG. 2A is a top view of the digital camera 1, and FIG. 2B is a side view. As shown in the figure, the digital camera 1 includes an imaging unit 2 and a camera body unit 3.

  The imaging unit 2 includes a photographing lens including a macro zoom and a photoelectric conversion element such as a CCD, and an optical image of a subject (subject light image) is formed of an image signal (an electric charge signal photoelectrically converted by each pixel of the CCD). Signal).

  A macro zoom lens 201 (to be described later) is provided inside the imaging unit 2, and an imaging circuit (not shown) including a CCD area sensor 202 (to be described later) is provided behind the location where the macro zoom lens 201 is provided. It has been.

  In addition, a dimming circuit (not shown) including a dimming sensor that receives reflected light from the subject of flash light is provided inside the image pickup unit 2.

  The camera body unit 3 includes an LCD display unit 6 including an LCD (Liquid Crystal Display), an EVF (Electronic View Finder) 7, and an external connection terminal 13 for connecting the digital camera 1 to a personal computer (not shown). The image signal captured by the imaging unit 2 is subjected to predetermined signal processing, image display on the LCD display unit 6 and EVF 7, image recording on a recording medium such as a memory card 14 described later, or personal Processing such as image transfer to a computer is performed.

  As shown in FIG. 1A, a flash 4 is provided at an appropriate position on the front surface of the camera body 3. As shown in FIG. 1B, an LCD display unit 6 and an EVF 7 for displaying a photographed image and reproducing and displaying a recorded image are provided at a substantially central portion on the back of the camera body unit 3.

  On the upper surface of the camera body 3, as shown in FIG. 2A, a shutter button 5 that captures a captured image and records it on the memory card 14, and a “recording mode” (REC in the figure) near the shutter button 5. ) And “playback mode” (PLAY in the drawing) are provided. The recording mode is a mode for taking a picture from the shooting standby state through the exposure control process to the shooting, and the playback mode is a mode for playing back and displaying the shot image recorded on the memory card 14 on the LCD display unit 6 or the EVF 7. It is.

  Further, as shown in FIG. 2A, a photographing sensitivity changeover switch 10 for switching photographing sensitivity is provided on the upper surface of the camera body 3. The shooting sensitivity changeover switch 10 can be switched from ISO 100 to ISO 800, for example, every time the switch is pressed, and the sensitivity suitable for the situation at the time of shooting can be selected.

  Further, an exposure adjustment mode switching switch 11 for switching the exposure adjustment mode is provided on the upper surface of the camera body 3. The exposure adjustment mode changeover switch 11 selects an automatic or manual exposure adjustment operation, and can select a shutter speed when performing a manual operation. That is, every time the exposure adjustment mode changeover switch 11 is pressed, for example, the mode is switched from auto, manual 30 seconds to manual 1/2000 seconds. That is, the exposure adjustment mode changeover switch 11 functions as an exposure control mode selection means according to the present invention.

  As shown in FIG. 1B, a playback frame advance switch / zoom switch 9 is provided on the rear surface of the camera body 3 for performing frame advance of a playback image and zooming operation during shooting. In the playback frame advance switch / zoom switch 9, the frame playback of the playback image is to set the camera to the playback mode and display the images recorded on the memory card 14 on the LCD display unit 6 together with the frame number. . Note that it is possible to instruct to change the image display on the LCD display unit 6 in the ascending order direction (direction of photographing order) or the descending order direction (direction opposite to the photographing order). The zoom operation at the time of shooting is to zoom the macro zoom lens 201 in the tele direction or the wide direction by operating the playback frame advance switch / zoom switch 9.

  Further, an EVF changeover switch 8 for selecting an LCD display unit 6 and an EVF 7 for displaying an image is provided on the back surface of the camera body unit 3.

  A battery 314 (not shown) is provided inside the bottom surface of the camera body 3 as a power source for operating the digital camera 1.

  Next, the control system of the digital camera 1 will be described with reference to FIG. FIG. 3 is a block diagram of a control system of the digital camera 1 according to the present invention. In FIG. 3, the same members as those shown in FIGS. 1 and 2 are given the same numbers.

  The macro zoom lens 201 in the imaging unit 2 is provided with a diaphragm member (fixed diaphragm) having a fixed aperture. The CCD area sensor 202 (hereinafter abbreviated as CCD 202) has R (red) light, G (green) light, and B (blue) light transmission filters arranged in a checkered pattern in pixel units (pixel units). The object light image formed by the macro zoom lens 201 by the color area image sensor is received as an image signal (each pixel unit) of each color component of R (red) light, G (green) light, and B (blue) light. The signal is converted into a signal comprising a signal string of the pixel signals thus obtained. That is, the CCD 202 functions as an imaging unit in the imaging apparatus according to the present invention.

  The imaging unit 2 can perform exposure control (adjustment of the exposure amount of the CCD 202) in the shooting standby state. However, in the shooting standby state, the aperture is set to an open fixed aperture by the aperture driver 208, so that exposure is performed by adjusting the charge accumulation time of the CCD 202. Control is performed. That is, the exposure control in the photographing standby state is performed by adjusting the charge accumulation time of the CCD 202 corresponding to the shutter speed.

  The charge accumulation time is adjusted as follows. First, exposure control data is calculated by a camera control CPU 311 provided in the camera body 3 based on a photometric area selected from light quantity data measured by the CCD 202. Based on the calculated exposure control data and preset program diagram data, exposure time data is calculated and sent to the timing generator 209. Based on these data, the timing generator 209 feeds back to the CCD 202 information on the charge accumulation time that is an appropriate exposure time, and the charge accumulation time is adjusted.

  Note that when the subject brightness is low, an appropriate shutter speed cannot be set and appropriate exposure control cannot be performed. In such a case, the gain adjustment of the AGC circuit 205 is performed along with the adjustment of the shutter speed. By doing so, appropriate exposure control can be realized.

  That is, in the case of low luminance, by combining the gain adjustment of the AGC circuit 205 in the signal processing circuit 203 with the shutter speed adjustment, a synergistic effect by both adjustments can be obtained, and the image signal level can be adjusted. Appropriate exposure control is realized.

  Further, the exposure control at the time of photographing is performed by determining the appropriate exposure amount to the CCD 202 by the aperture driver 208 and the timing generator 209 based on the exposure control data calculated by the camera control CPU 311 and information based on a preset program diagram. Be controlled.

  The timing generator 209 generates a drive control signal for the CCD 202 on the basis of a reference clock transmitted from a reference clock generation unit 308 of the camera main body 3 described later. The drive control signal generated by the timing generator 209 includes, for example, an integration start / end timing signal for controlling the exposure start and end timing in the CCD 202, and a readout control signal (horizontal synchronization signal, vertical synchronization signal) of the light reception signal of each pixel. , Transfer signals, etc.), and when these clock signals are supplied to the CCD 202, the CCD 202 performs drive control corresponding to each clock signal. In this manner, the timing generator 209 functions as a drive control signal generation unit in the imaging apparatus according to the present invention.

  When the charge accumulation is completed (that is, when the exposure control of the digital camera 1 is completed), the image signal formed by the photoelectric conversion is shifted to the light-shielded transfer path in the CCD 202 and read out through the buffer. The image signal read from the CCD 202 is taken into the signal processing circuit 203 and subjected to predetermined processing.

  As shown in FIG. 3, the signal processing circuit 203 includes a CDS circuit 204 and an AGC circuit 205, and a predetermined process is performed on the image signal via these components. Hereinafter, the predetermined processing for the image signal performed by the signal processing circuit 203 will be described.

  A CDS (Correlated Double Sampling) circuit 204 reduces noise generated at the time of reading from an image signal read from the CCD 202 and corrects dark noise by an OB clamp operation.

  The AGC circuit 205 performs gain adjustment on the image signal processed by the CDS circuit 204 based on the photographing sensitivity selected by the photographing sensitivity changeover switch 10 described above, and controls photographing sensitivity.

  The A / D converter 206 converts each pixel signal constituting the image signal input from the AGC circuit 205 into a 14-bit digital signal. The A / D converter 206 converts each pixel signal of the analog signal into a 14-bit digital signal based on the A / D conversion clock input from the reference clock generation unit 308.

  The image signal read by the CCD 202 is subjected to predetermined processing by the signal processing circuit 203 and the A / D converter 206 and converted into a digital image signal. The digitized image signal is captured by the image processing CPU 301 and subjected to predetermined processing.

  The image processing CPU 301 is composed of a microcomputer and controls the photographing operation of the digital camera 1 by controlling the operation of each member constituting the imaging unit 2 and the camera body unit 3 described above. In the following, processing for a digital image signal performed by the image processing CPU 301 will be described.

  First, the image signal captured by the image processing CPU 301 is written into the image memory 313 in synchronization with the reading of the image signal output from the CCD 202. That is, a digital image signal used for processing performed by the image processing CPU 301 is recorded once in the image memory 313 and is taken out from the image memory 313 and used for processing in each block.

  The image processing CPU 301 performs predetermined processing on the digital image signal extracted from the image memory 313, and performs predetermined processing at a portion from the pixel interpolation unit 302 to the matrix calculation unit 306 shown in FIG. 3.

  The pixel interpolation unit 302 masks the image data recorded in the image memory 313 with R, G, and B pixel filter patterns, and then performs average interpolation (also referred to as pixel interpolation). Among these, the G pixel filter pattern having pixels up to a high band is a median filter that performs average interpolation by substituting the average value of the intermediate binary values of the surrounding four pixels, and the R and B pixel filters. The pattern is an average interpolation for the same color from the surrounding nine pixels.

  The resolution conversion unit 303 performs a reduction process and a thinning process in the horizontal direction and the vertical direction on the image signal subjected to the pixel interpolation by the pixel interpolation unit 302, and the recorded image pixel set by the imaging unit 2 of the digital camera 1. The resolution is converted to a resolution corresponding to the number. At the same time, it is also possible to perform a horizontal pixel thinning process on the monitor display image signal and convert it to a low resolution image signal that can be displayed on the LCD display unit 6 or the EVF 7.

  A white balance control unit (WB control unit) 304 performs level conversion on the image signals of the R, G, and B color components subjected to resolution conversion processing by the resolution conversion unit 303. This is called processing. In the white balance processing, for example, image data relating to a color measurement area on the imaging surface that is set in advance is read from data written in the image memory 313 at the time of shooting standby, and the luminance and saturation of the read image data are read. From the above data, etc., the part originally supposed to be white is estimated, the average intensity of each part, the G / R ratio, and the G / B ratio are obtained and corrected as R and B correction gains. Control is performed.

  The gamma correction unit 305 corrects the γ characteristic of the image signal and converts the image signal into a signal suitable for the characteristics of the output device. As a specific processing method, for example, a non-linear conversion process is performed and 8-bit data is converted. The method of converting into the image signal of this is mentioned.

  The matrix calculation unit 306 converts the image signals R, G, and B subjected to the gamma correction processing into a luminance signal (Y signal) and a color difference signal (Cr (R−Y) signal, Cb (B−Y) signal). . Then, the digital image signal that has undergone predetermined processing at these parts is stored in the image memory 313 again.

  The reference clock generation unit 308 is a circuit that generates a reference clock used for driving control of the digital camera 1 and supplies the reference clock to each circuit. Specific examples of the reference clock in the present invention include a reference clock used for the timing generator 209, an A / D conversion clock used for the A / D converter 206, and the like. Generate a clock. Thus, the reference clock generation unit 308 functions as a reference signal generation unit in the imaging apparatus according to the present invention. The frequency of the reference clock generated by the reference clock generator 308 is controlled so as to vary by a camera control CPU 311 described later.

  The LCD driver 309 encodes the image signal read from the image memory 313 by the image processing CPU 301 into NTSC / PAL, and displays the image on the LCD display unit 6 and the EVF 7 as a field image.

  The camera control CPU 311 is composed of a microcomputer, and based on switch signals generated by switch operations of a switch group 315 to be described later, sequentially controls the drive of each member in the imaging unit 2 and the camera body unit 3 to control the digital camera. The overall shooting operation of 1 is controlled.

  The camera control CPU 311 controls the exposure of the digital camera 1. When the auto adjustment mode is selected by the exposure adjustment mode changeover switch 11, the camera control CPU 311 automatically operates during shooting standby and shooting as described above. Although exposure adjustment is performed, when the manual mode is selected, the camera control CPU 311 calculates exposure control data based on the selected shutter speed. Then, based on the calculated exposure control data and preset program diagram data, exposure time data is calculated and sent to the timing generator 209. Based on these data, the timing generator 209 feeds back to the CCD 202 information on the charge accumulation time that is an appropriate exposure time, and the charge accumulation time is adjusted. In this manner, the camera control CPU 311 functions as an exposure control unit in the imaging apparatus according to the present invention.

  Further, the camera control CPU 311 controls the frequency of the reference clock generated by the reference clock generation unit 308 of the digital camera 1, and in the present invention, the frequency of the reference clock is changed based on the shooting conditions set at the time of shooting. It is possible. That is, the camera control CPU 311 presets a reference exposure control value (shutter speed value) as a threshold for changing the reference clock frequency, and compares the calculated exposure control data with the reference exposure control value (shutter speed value). . When the value of the exposure control data is lower than the reference exposure control value, control is performed so that the frequency of the reference clock generated by the reference clock generation unit 308 is reduced. As described above, the camera control CPU 311 has a function of changing the frame rate based on the set shutter speed to change the frequency of the reference signal, and functions as a reference signal control unit in the imaging apparatus according to the present invention. It is.

  Reference signal control performed by the camera control CPU 311 will be further described. In the present invention, the camera control CPU 311 previously sets a threshold value for the shutter speed value as the reference exposure control value. Then, the threshold value is compared with the shutter speed value set at the time of shooting, and the frame rate setting is changed based on the comparison result. Specifically, when it is determined that the set shutter speed value is lower than the threshold shutter speed, the camera control CPU 311 sets the frequency so that the frequency of the reference clock generated by the reference clock generation unit 308 is reduced. To change. Then, the reference clock generation unit 308 transmits the reference clock that has been reduced in speed to the timing generator 209, and the timing generator 209 controls the driving of the CCD 202 based on the reference clock that has been reduced in speed.

  In this way, in the present invention, the frame rate setting can be changed according to the shooting scene by reducing the pixel transfer clock of the CCD 202, so that the power consumption can be reduced when shooting at a low shutter speed. It is possible to realize.

  The image processing CPU 301 includes an image compression unit 307 that compresses a captured image. The image compression unit 307 performs image compression processing such as a JPEG (Joint Photographic Coding Experts Group) method on the captured image, and performs predetermined processing. The image data compressed to the compression ratio is generated. The compressed image data is recorded on the memory card 14 via the memory card driver 310.

  As described above, in the digital camera 1, the image processing CPU 301 performs the signal processing as described above on the image signal captured from the imaging unit 2, and records the image signal subjected to these processing in the image memory 313. ing.

  The digital camera 1 according to the present invention records the image signal captured by the imaging unit 2 under the mode set by the shooting mode switch 12 in the image memory 313 or displays it on the LCD display unit 6 or the EVF 7. .

  In the shooting standby state (state in which the recording mode (REC) is set with the shooting mode changeover switch 12), the image signal is taken into the camera body 3 from the imaging unit 2 at a predetermined interval such as every 1/30 seconds. As described above, the captured image signal is subjected to predetermined signal processing at a portion from the pixel interpolation unit 302 to the matrix calculation unit 306 in the image processing CPU 301, and then recorded in the image memory 313 as a digital image signal. The

  Then, the image signal recorded in the image memory 313 is read out, the read image signal is encoded into NTSC / PAL by the LCD driver 309, and this is displayed as an image on the LCD display unit 6 or EVF 7 as a field image.

  Further, at the time of image recording, the image signal is compressed by the image compression unit 307 in order to obtain an image of the set recording resolution as described above, and the obtained compressed image is stored in the memory card via the memory card driver 310. 14 is recorded.

  In the reproduction mode (the state in which the reproduction mode (PLAY) is set by the photographing mode changeover switch 12), the image signal read from the memory card 14 is a part from the pixel interpolation unit 302 to the matrix calculation unit 306 in the image processing CPU 301. Then, predetermined signal processing is performed and the image is displayed on the LCD display unit 6 and the EVF 7 via the LCD driver 309.

  The switch group 315 in FIG. 3 includes the shutter button 5, EVF switch 8, playback frame advance switch / zoom switch 9, shooting sensitivity switch 10, exposure adjustment mode switch 11, shooting mode in FIGS. 1 and 2. This switch corresponds to the changeover switch 12.

  Here, the reduction in power consumption (energy saving method) by reducing the drive signal speed of the CCD 202 performed in the digital camera 1 according to the present invention will be described in detail with reference to the flowchart of FIG.

  First, the digital camera 1 is set to a recording mode and put in a shooting standby state. In the shooting standby state, a shooting standby image is displayed on the LCD display unit 6 of the digital camera 1 (step S1).

  Next, the camera control CPU 311 acquires the exposure adjustment value determined under the exposure adjustment mode selected by the exposure adjustment mode changeover switch 11. Specifically, when the auto mode is selected by the exposure adjustment mode changeover switch 11, the shutter speed value calculated by the automatic exposure adjustment is selected. When the manual mode is selected, the selected shutter is selected. A speed value is acquired (step S2).

  The camera control CPU 311 sets a threshold value in advance for the shutter speed value (for example, in the present invention, the shutter speed value is 1 second), and compares this threshold value with the acquired shutter speed value ( Step S3), it is determined whether or not the shutter speed value is higher than a threshold value (Step S4). When the acquired shutter speed value is lower than the threshold value (step S4; Yes), the camera control CPU 311 can reduce the drive signal of the CCD 202, so that the camera control CPU 311 generates the reference generated by the reference clock generation unit 308. Frequency setting control is performed so as to reduce the clock frequency (step S5).

  Then, the timing generator 209 can perform drive control of the CCD 202 based on the reduced reference clock transmitted from the reference clock generator 308 (step S6). In this way, by reducing the pixel transfer clock of the CCD 202, the power consumption can be greatly reduced.

  On the other hand, when the acquired shutter speed value is higher than the threshold value (step S4; No), the process is completed without reducing the drive signal of the CCD 202.

  Further, in the step S4, the operation of determining the acquired shutter speed value with one threshold value and reducing the pixel transfer clock of the CCD 202 has been described. However, a plurality of threshold values are set and the shutter speed value is set according to the shutter speed. By reducing the pixel transfer clock of the CCD 202 stepwise, the power consumption can be more efficiently reduced (energy saving).

  As described above, in the imaging apparatus according to the present invention, by reducing the pixel transfer clock of the imaging device according to the shooting scene, the power consumption can be greatly reduced, and efficient energy saving measures can be taken. became.

It is the front view and back view of the digital camera which concern on this invention. It is the top view and side view of the digital camera which concern on this invention. It is a block block diagram in the digital camera which concerns on this invention. It is a flowchart which shows the flow of CCD drive signal frequency control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Imaging part 201 Macro zoom lens 202 CCD area sensor 203 Signal processing circuit 204 CDS circuit 205 AGC circuit 206 A / D converter 207 Focus motor driver 208 Aperture driver 209 Timing generator 3 Camera main body 301 Image processing CPU
302 Pixel Interpolation Unit 303 Resolution Conversion Unit 304 White Balance Control Unit 305 Gamma Correction Unit 306 Matrix Operation Unit 307 Image Compression Unit 308 Reference Clock Generation Unit 309 LCD Driver 310 Memory Card Driver 311 Camera Control CPU
312 DC / DC converter 313 Image memory 314 Battery 315 Switch group 4 Flash 5 Shutter button 6 LCD display 7 EVF
8 EVF selector switch 9 Playback frame advance switch / zoom switch 10 Shooting sensitivity selector switch 11 Exposure adjustment mode selector switch 12 Shooting mode selector switch 13 External connection terminal 14 Memory card

Claims (3)

Imaging means for photoelectrically converting a subject light image to generate an image signal;
Drive control signal generating means for generating a control signal for controlling driving of the imaging means;
Reference signal generating means for generating a reference signal used in the drive control signal generating means;
Reference signal control means for controlling the operation of the reference signal generation means;
Exposure control means for performing exposure control of the imaging means based on the image signal, the reference signal control means,
An image pickup apparatus that controls the operation of the reference signal generation means so that the frequency of the reference signal generated by the reference signal generation means varies based on an exposure control value set by the exposure control means. . The reference signal control means includes
Having a preset reference exposure control value,
The exposure control value set by the exposure control means is compared with the reference exposure control value, and control is performed so as to change the frequency of the reference signal generated by the reference signal generating means based on the comparison result. The imaging apparatus according to claim 1. Exposure control mode selection means for selecting processing contents in the exposure control means;
The reference signal control means operates the reference signal generation means so that the frequency of the reference signal generated by the reference signal generation means varies based on the exposure control value selected by the exposure control mode selection means. The imaging apparatus according to claim 1, wherein the imaging apparatus is controlled.

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