JP2007312432A - Electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic camera which increases a refreshing rate for images in the case of an ordinary photographing, or AE (Automatic Exposure) and AF (Automatic Focus) photographing, and obtains an image corresponding to a large number of pixels in the case of a macro-photographing mode, or when outputting the image to an external monitor. <P>SOLUTION: In the case of ordinary photographing, or AE and AF photographing, the solid-state image sensor 28 is driven by thinning out its vertical direction lines to 1/4 or 1/8. In this case, although the image is somewhat coarse, the refreshing rate is high and the power consumption is small. When the operation mode is changed to a macro-photographing mode or when the image signal is output externally for confirmation of the image quality (when connected to external output), the sensor 28 is driven by automatically thinning out to 1/2 or driven without thinning out. Thereby, an image corresponding to the large number of pixels can be taken in, and more stringent focus confirmation is made in confirming a macro, and a highly precise image is viewed on an external large screen monitor display. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic camera, and more particularly to an electronic camera using an imaging device driving method suitable for use in a digital camera or the like equipped with a high-pixel imaging device having more than 1 million pixels.

  The conventional digital camera has a relatively small number of pixels of an image pickup device of about 640 × 480, so modes such as AF (autofocus), AE (automatic exposure control), normal shooting, and macro shooting are available. Regardless, the imaging device is always driven by the same driving method, and signal charges for all the pixels are read out (this is referred to as normal driving). However, with the demand for higher image quality, digital cameras with a larger number of pixels have been developed. If the image pickup device is normally driven during AE or AF as the number of pixels increases, the signal processing takes time. It's no longer in time. In view of this, it has been proposed to devise the vertical drive of the image pickup device and drive it by thinning out the vertical readout from about 1/2 to 1/4 during AE or AF.

  However, the conventional method of thinning out the vertical has the advantage that if the amount of thinning out is increased, the refresh of the image will be faster, but the data in the vertical direction will be lost. Cannot be confirmed, and there is a drawback that the picture looks rough when output to the outside and displayed on a monitor or the like.

  The present invention has been made in view of such circumstances, and the refresh rate is increased during normal shooting or AE / AF, and in the case of macro shooting mode or output to an external monitor, a high pixel image is obtained. In addition to providing a driving method of an imaging device capable of obtaining the above, an object is to provide an electronic camera to which the method is applied.

  According to a first aspect of the present invention, there is provided an electronic camera that images a subject using an imaging device in which photoelectric conversion elements are two-dimensionally arranged, an image display unit that displays an image acquired by the imaging device, and an external An output terminal for connecting a device, a detection means for detecting that an external device is connected to the output terminal, and a vertical direction of the imaging device in a normal shooting mode in which the external device is not connected to the output terminal When the signal is read out at the first ratio and the connection of the external device to the output terminal is detected by the detection means, the vertical direction of the imaging device is less thinned than in the normal shooting mode. Drive control means for driving the imaging device so that signals are read out at the second rate, or signals are read out for all pixels without being thinned out. Characterized by comprising a.

  According to a second aspect of the present invention, in an electronic camera that images a subject using an imaging device in which photoelectric conversion elements are two-dimensionally arranged, an image display unit that displays an image acquired by the imaging device; External output means for sending a video signal acquired via the imaging device to an external device, normal shooting mode in which the external output means does not transfer the video signal to the external device, and video to the external device by the external output means A mode selection means for performing an operation of selecting one of the external output modes for signal transfer; and when the normal shooting mode is selected by the mode selection means, the vertical direction of the imaging device is When the signal is read out at a rate of 1 and the external output mode is selected by the detection mode selection means, the imaging device is Drive control means for driving the imaging device so that signals are read out by thinning the direction to a second rate with less thinning than in the normal shooting mode, or signals are read out for all pixels without thinning out; It is characterized by having.

  An imaging device driving method according to the present invention is an imaging device driving method for reading a signal from an imaging device incorporated in an imaging apparatus. In the normal imaging mode, the imaging device is driven in the vertical direction by a first ratio. In the macro shooting mode, or when an external output is connected to output an image signal to an external image display device, the second rate of the imaging device in the vertical direction is less than that in the normal shooting mode. It is characterized in that signals are read out by thinning out signals, or signals are read out for all pixels without being thinned out.

  According to the driving method of the imaging device according to the present invention, in the normal shooting mode that is used on a daily basis, the imaging device is driven by thinning the vertical of the imaging device to the first ratio. The image acquired at this time becomes rough, but the refresh rate is high, and it is sufficient for confirmation of the composition in a range where the image is observed with a small screen display (monitor) attached to the imaging apparatus.

  When the mode is switched to the macro photography (short-distance photography) mode, the thinning is reduced (decimated to the second ratio) or the driving is performed without thinning. As a result, more pixel data can be captured than in the normal shooting mode, and more precise focus confirmation can be performed. Also, regardless of whether the macro shooting mode is provided or not, when the external output is connected, the thinning is reduced (thinning to the second ratio) or driving without thinning is performed even in the normal shooting mode. . As a result, a high-definition image can be viewed when the captured image is output externally and checked on another large screen monitor (image display device) or the like.

  In particular, in the method for driving an imaging device according to the present invention, when the number of times an image for one screen is refreshed per unit time is referred to as a refresh rate, refresh of an image acquired by the imaging device in the normal shooting mode. A mode in which the rate is adjusted to the frame frequency in a predetermined color television system such as NTSC, PAL, SECAM or the like is preferable. According to this aspect, since it is not necessary to once store the image acquired by the imaging device in the frame memory, it is possible to cut off the power of the memory and the like, and it is possible to suppress wasteful power consumption. There is.

  According to a third aspect of the present invention, there is provided an electronic camera that images a subject using an imaging device in which photoelectric conversion elements are two-dimensionally arranged to provide an electronic camera that embodies the method invention. An image display means for displaying an image acquired by the device, a mode switching means for changing the mode between the normal shooting mode and the macro shooting mode, and the vertical direction of the imaging device in the normal shooting mode is a first ratio. In the macro shooting mode, the signal is read out for all the pixels without thinning out the signal in the vertical direction of the imaging device to a second rate that is less thinned than in the normal shooting mode. Drive control means for driving the imaging device to perform reading.

  According to the third aspect of the present invention, when the normal shooting mode is selected, driving is performed by thinning the vertical of the imaging device to the first ratio, and when the macro shooting mode is selected by the mode switching means. Automatically reduce the decimation or drive the imaging device without decimation. As a result, a high-pixel image can be captured during macro shooting, and more precise focus confirmation can be performed.

  An electronic camera according to a fourth aspect of the present invention is the electronic camera according to the above aspect, further comprising an external output unit that sends the video signal acquired via the imaging device to an external image display device, and the external output unit via the external output unit. At the time of external output connection for outputting the video signal to the image display device, the signal is read out or thinned out by thinning out the vertical direction of the imaging device to a third rate (1/2) which is thinned out less than in the normal shooting mode. It is preferable that the signal is read out for all the pixels without performing it. The third ratio may be the same as the second ratio.

  According to this aspect, even in the normal shooting mode, when the external output is connected, the thinning is automatically reduced or the driving is performed without the thinning, so that the image quality is high when the image is displayed on the external image display device. Can be observed. This is particularly effective when using a large screen monitor.

  Further, according to a fifth aspect of the present invention, in the electronic camera of the present invention described above, a high-quality confirmation mode that can be set as needed according to an external operation is provided, and when the high-quality confirmation mode is set, The drive control means unconditionally reads out the signal by thinning out the vertical direction of the imaging device to the fourth ratio (1/2), which is less thinned than in the normal photographing mode, or outputs signals for all pixels without performing thinning out. Is read out. The fourth ratio may be the same as the second or third ratio.

  That is, the electronic camera can be set to the high image quality confirmation mode by the user operating a predetermined operation unit as necessary. Even when the normal shooting mode is selected, if the user sets the high image quality confirmation mode, the thinning is unconditionally reduced (thinning to the fourth ratio) or the driving is performed without thinning. According to this aspect, the user can freely select whether to view an image with a high pixel even if the refresh rate is slow, or to view an image with a fast refresh rate even if the image is somewhat coarse.

  As described above, according to the imaging device driving method and the electronic camera according to the present invention, the image is somewhat rough but has a high refresh rate when used daily (in normal shooting mode) or during AE / AF. Thinning drive with low power consumption is performed and refresh rate is slow when in macro shooting mode or when an external output is connected, but driving with less thinning (or no thinning) is performed, so when checking macros and images A high pixel image can be seen when checking by external output.

  Hereinafter, preferred embodiments of an imaging device driving method and an electronic camera according to the present invention will be described in detail according to the accompanying drawings.

  First, the thinning drive of the imaging device will be described. FIG. 1 shows an example of a CCD imaging device. Although the number of pixels is reduced in the drawing for the sake of convenience, the pixel number actually exceeds SVGA, such as 1280 × 1024 or 1280 × 960. In front of each pixel, a color filter of R (red), G (green), or B (blue) is provided. The pixel array shown in FIG. 1 is called a Bayer array, but the array form is not limited to this.

  The imaging device 10 mainly includes a photoelectric conversion element 12, a vertical transfer path 14, a horizontal transfer path 16, and the like. The photoelectric conversion elements 12 are two-dimensionally arranged, and pixel columns and vertical transfer paths 14 are alternately arranged for each column in the vertical direction in the drawing. Each photoelectric conversion element 12 is connected to the vertical transfer path 14 via a read gate (not shown). The final stage (the lowest stage in the figure) of the vertical transfer path 14 is connected to the horizontal transfer path 16, and the final stage (the leftmost stage in FIG. 1) of the horizontal transfer path 16 is connected to an output unit (not shown).

  The readout gate is controlled by a readout gate pulse given from a CCD drive circuit (imaging device drive circuit), and when the readout gate pulse is applied, the signal charge accumulated in the photoelectric conversion element 12 enters the vertical transfer path 14. Moved. It should be noted that the charge that is not required when the shutter operation is performed is swept away by the CCD substrate in advance by the shutter gate pulse preceding the readout gate pulse.

  The vertical transfer path 14 vertically transfers the signal charge read from the photoelectric conversion element 12 in the downward direction of FIG. 1 by a vertical transfer pulse applied from the CCD drive circuit. The signal charges transferred to the final stage of the vertical transfer path 14 are sequentially transferred to the horizontal transfer path 16 every horizontal blanking period.

  The horizontal transfer path 16 transfers signal charges to an output unit (not shown) by a horizontal transfer pulse applied from the CCD drive circuit. The output unit detects the charge of the input signal charge and outputs it as a signal voltage to the output terminal. Thus, in normal driving, signals are read from all pixels and output as a dot-sequential signal sequence.

  Next, an example of 1/2 thinning driving will be described.

  FIG. 2 shows an example of 1/2 thinning driving. The method shown in FIG. 5A is a method in which pixels are thinned out evenly every other horizontal line. As shown in FIG. 2A, when reading a line including B (blue) (first, third, and fifth rows in the figure), G (green) and B (blue) are used as color information in one reading drive. ) Information can be read out, and R (red) color information is missing. Therefore, the line including R (second and fourth rows in the figure) is read by the next drive, and the color information is aligned by a total of two read drives. In this way, in the case of the Bayer arrangement, a method of performing driving by 1/2 equal thinning twice is adopted, but other arrangement forms (for example, an arrangement called a G stripe in which all color information is included in one horizontal line) In the case of (), all the color information can be made uniform by one reading drive by 1/2 equal thinning. The interlace transfer drive type CCD and the like read signal charges by such a method.

  On the other hand, the method shown in FIG. 2B is a reading method in which two lines are read and two lines are skipped. In this way, the method of thinning out every two lines has an advantage that all color information can be obtained by one read drive even in the Bayer array.

  Next, an example of 1/4 thinning driving will be described.

  FIG. 3A shows a uniform reading method in which 1/4 thinning is performed uniformly in the vertical direction and one line is read and three lines are skipped. Also in this case, the read line is shifted by one line in the next drive, and the line including R (R line) is read, so that the color information is aligned in two read drives.

  Also, instead of equal thinning, as shown in FIG. 3B, the number of lines to be skipped is alternately changed to 2 lines or 5 lines, and the R line indicated by (I) (or (II)) is read simultaneously. Thus, all the color information can be made uniform by one read drive.

  Next, an example of 1/8 thinning driving will be described.

  The 1/8 thinning driving is basically the same as the 1/4 thinning driving, and FIG. 4A shows an example of uniform reading. In this case, 1/8 is thinned out in the vertical direction, and one line is read and seven lines are skipped. In addition, since all color information cannot be obtained by one drive, the R line is read by the next drive, and the color information is aligned by the second drive.

  On the other hand, instead of such uniform thinning, as shown in FIG. 4B, the number of lines to be skipped is alternately changed to 6 lines or 8 lines, and the R line indicated by (I) (or (II)) is read. Thus, all the color information can be made uniform by one read drive.

  The above thinning driving example (FIGS. 1 to 4) has been described on the assumption of a CCD. However, the present invention is not limited to this, and is applicable to thinning readout of MOS type, CID type and other imaging devices. Can do.

  An imaging apparatus having an imaging device has the above-described imaging device driving method. A combination of such a driving method and a shooting mode will be described below.

  FIG. 5 is a system block diagram of the digital camera according to the embodiment of the present invention. A digital camera (equivalent to an electronic camera) 20 mainly includes a photographing lens 22, an aperture 24, a mechanical shutter 26, a solid-state imaging device (equivalent to an imaging device) 28, an analog signal processing circuit 30, an A / D converter 32, a digital signal. The processing unit 34, a memory 36, a D / A converter 38, a liquid crystal monitor 40, a compression / decompression circuit 42, a memory card 44, a control circuit 46, a central processing unit (CPU) 48, and the like. The control circuit 46 and the CPU 48 correspond to drive control means.

  Although the photographic lens 22 is shown in a simplified manner in the drawing, it is composed of one or a plurality of lenses, and may be a lens having a single focal length (fixed focal point), or a zoom lens or a step zoom lens. The focal length may be variable. The photographing lens 22 is controlled in focus and zoom through a control circuit 46.

  The diaphragm 24 is formed, for example, by forming a plurality of diaphragm holes having different diameters on a single diaphragm plate, and the diaphragm can be switched by an electric drive means (not shown). In the figure, the diaphragm 24 is shown as a diaphragm plate having two types of diaphragm holes. However, when the diaphragm is fixed, or when the diaphragm is a continuous diaphragm that can be changed continuously (steplessly), Alternatively, a form in which the shutter and the aperture are shared is also possible.

  The mechanical shutter 26 is formed of a light-shielding plate that can be moved forward and backward in the incident optical path of the solid-state image sensor 28, and shields / opens the incident optical path of the solid-state image sensor 28 by electric drive means (not shown) controlled via the control circuit 46. .

  As the solid-state imaging device 28, a known two-dimensional imaging device (for example, 1280 × 960 pixels) is used. There are various types of imaging devices such as a CCD type, a MOS type, and a CID type, and any type of imaging device may be adopted. In this embodiment, the CCD imaging device as described in FIG. Is adopted. The solid-state image sensor 28 has a so-called electronic shutter function that controls the accumulation time (shutter speed) of charges accumulated in each sensor by a shutter gate pulse.

  The light that has passed through the photographing lens 22 is regulated by the diaphragm 24 and the mechanical shutter 26 and projected onto the solid-state image sensor 28. On the solid-state image sensor 28, the accumulation time is controlled by an electronic shutter. Of course, the diaphragm 24 may be fixed, or the mechanical shutter 26 and the diaphragm 24 may be shared, or the mechanical shutter 26 may be unnecessary if the imaging device reads all pixels.

  The subject image formed on the light receiving surface of the solid-state image sensor 28 is converted into signal charges of an amount corresponding to the amount of incident light by each sensor, and sequentially read out as an imaging output signal, and then the analog signal processing circuit 30. To be supplied.

  The analog signal processing circuit 30 includes a CDS clamp circuit, a gain adjustment circuit, and the like, and appropriately processes an imaging output signal (analog electrical signal) input from the solid-state imaging device 28 based on control of the control circuit 46. The signal output from the analog signal processing circuit 30 is converted into a digital signal by the A / D converter 32 and then added to the digital signal processing unit 34.

  A digital signal processing unit 34, a gain control unit, an AE integrating circuit, a luminance (Y) signal generation circuit, a color difference (C) signal generation circuit, and other signal processing circuits are included. The data output from the A / D converter 32 is appropriately processed by the digital signal processing unit 34, and the image data obtained here is temporarily stored in the memory 36.

  The image data stored in the memory 36 is decoded, converted to an analog signal by a D / A converter 38, and supplied to a liquid crystal monitor 40 (corresponding to image display means). In this way, the image captured by the solid-state image sensor 28 is displayed on the liquid crystal monitor 40. The liquid crystal monitor 40 displays a still image shot based on reception of a shooting start signal generated by pressing a shutter button (not shown) or the like, and a video (through moving image or intermittent video) before receiving a shooting start signal. Screen) is also displayed. Note that the imaging start signal may be externally applied. The signal converted into an analog signal by the D / A converter 38 can be taken out as an external video output from an external output means 41 such as a video output terminal or a digital output terminal.

  On the other hand, when the image data acquired in response to the reception of the photographing start signal is recorded on the memory card 44 or other recording medium, it is compressed and written as necessary. It is also possible to select the compression rate of the recorded image. That is, the data led from the memory 36 to the compression / decompression circuit 42 is compressed according to a predetermined format (for example, JPEG), and then the memory card. 44. It is also possible to select the compression rate of the recorded image, and one of 1/4 compression, 1/8 compression, and 1/16 compression can be selected according to the purpose of shooting. The form of the recording medium can be various forms such as smart media and IC card.

  The image data stored in the memory card 44 can be called up via the CPU 48, and the called image data is decompressed and reproduced by the compression / decompression circuit 42 and then the liquid crystal is sent via the memory 36 and the D / A converter 38. It is output to the monitor 40. Of course, the reproduced image signal is also supplied to the external output means 41 and can be output to other external devices.

  The CPU 48 is connected to the control circuit 46, the digital signal processing unit 34, the memory 36, etc., and performs various calculations such as exposure value and focus position according to a predetermined algorithm, and performs automatic exposure control, auto focus, auto strobe, auto white. The balance and other controls are comprehensively managed. The CPU 48 controls a corresponding circuit based on various input signals input from a release button, a macro key (corresponding to a mode switching means), a mode setting dial, and other operation units 50.

  The autofocus means can take various forms. For example, the focus evaluation value indicating the sharpness of the subject image is calculated from the image signal, and the focus position is calculated based on the focus evaluation value. Then, the photographing lens 22 is controlled through a focus driving circuit (not shown) according to the calculated focus position, and the focus position is set. In addition, a known distance measuring means such as an AF sensor may be used.

  The control circuit 46 controls the drive circuit of the solid-state image sensor 28 based on the exposure control value notified from the CPU 48, sets the charge accumulation time of the solid-state image sensor 28, that is, the electronic shutter value, and selects the diaphragm 24. The opening / closing timing of the mechanical shutter 26 is controlled. In this way, all exposure control of the digital camera 20 is automatically performed.

  Next, a method for driving the imaging device in the digital camera configured as described above will be described.

  First, the case of the normal shooting mode is described. The normal shooting mode is a shooting mode in which the camera automatically controls exposure (combination of shutter speed and aperture value) and focus according to shooting conditions, and is optimal for general shooting. In this normal photographing mode, the solid-state image sensor 28 is driven by the ¼ thinning or the ８ thinning described with reference to FIGS. 3 and 4. In such a case, the image is rough (in the case of 960 vertical lines, 240 lines are reduced by 1/4 thinning and 120 lines are thinned by 1/8 thinning), but the refresh rate is high and the small liquid crystal monitor 40 attached to the digital camera 20 is used. In the range to be observed, it is sufficiently effective for confirming the composition.

  Further, if the refresh rate is set in accordance with the NTSC, PAL, SECAM, or other formats employed for the display of the liquid crystal monitor 40, it is not necessary to store the image in the memory once. Can be cut off. In this case, the system is configured as shown in FIG. 6, and power consumption can be suppressed.

  Even during AE and AF, driving is performed by 1/4 thinning or 1/8 thinning in the vertical direction, or by cutting out the central portion of 1/2. Thereby, AE and AF processing can be performed in a short time.

  Next, the case of the macro (short distance) shooting mode will be described. When a key corresponding to a macro key in the operation unit 50 is pressed, the camera is set to the macro shooting mode, and a predetermined mark indicating that the mode is the macro shooting mode is displayed on the liquid crystal monitor 40. When the macro shooting function is used, short-distance shooting up to about 9 to 50 cm becomes possible. When the macro key is pressed again, the macro shooting mode is canceled and the normal shooting mode is restored.

  When the macro photographing mode is set, as described with reference to FIGS. 1 and 2, the solid-state imaging device 28 is driven with 1/2 thinning or no thinning. In macro photography, the focus is much more severe than in normal photography, and it is preferable to obtain a fine image with a large number of pixels for confirmation of the in-focus state. Therefore, when the macro shooting mode is set, the solid-state image sensor is configured so that the thinning is automatically reduced (vertical driving is thinned to ½) or all pixels are read without being thinned. 28 is driven and controlled. Thereby, an image with higher image quality than in the normal shooting mode can be obtained.

  In addition, in the case of a macro, there are cases where it is desired to mainly check and enlarge the central portion of the screen for focus confirmation. In order to respond to such a request, a confirmation operation unit such as a center enlargement button may be provided, and the confirmation operation unit may be operated so that the center of the screen can be enlarged and displayed. In order to realize such a central enlarged display function, a method of processing as follows by combining driving of the imaging device and monitor display is conceivable.

  That is, first, as shown in FIG. 7, when a high-pixel imaging device is read by normal driving (no thinning) and displayed, only the central portion 52A of the imaging area 52 is cut out and displayed. . A display device such as the liquid crystal monitor 40 can display approximately one-to-one with respect to the pixels if the number of pixels is approximately 320 × 240, and the focus and the like can be confirmed severely.

  Second, as shown in FIG. 8, a high-pixel imaging device (for example, 1280 × 960 pixels) is driven by 1/2 thinning to perform 1280 × 480 reading, and the reading area 54 is centered in the vertical direction. Only the portion 54A is cut out in half (shaded area in FIG. 8), the horizontal is cut down from 1280 to 1/2, then only the center portion is cut out in half, and finally displayed in a size of 320 × 240 To do.

  By performing such processing, as a result, as shown in FIG. 9, a 320 × 240 region corresponding to the display area 56 is cut out from a part of the imaging area 52 and displayed.

  As shown in FIG. 10, in the third method, the area in the vertical central portion 1/2 is defined as the readout area 52B in the imaging area 52 of the high-pixel imaging device (for example, 1280 × 960 pixels). Only the read area 52B is read and driven by half-thinning. When this is displayed, the horizontal portion is reduced to ½, and the central portion is cut out to ½ and displayed. With this processing, the relationship between the imaging area 52 and the display area 56 is the same as that shown in FIG.

  Next, a method for driving the imaging device when external output is connected will be described.

  When a large screen monitor or other image display device is connected to the video output terminal, or when a personal computer (computer) is connected to the digital output terminal, that is, when outputting a video signal to an external device (when external output is connected) In the standard shooting mode, the driving is automatically performed without ½ thinning or thinning. Of course, in the macro mode, the driving is similarly performed with 1/2 thinning or no thinning.

  Specifically, a means for detecting that the device is connected to the output terminal is provided, and when the detecting means detects the connection of the external device, the CPU 48 is notified of the detection signal and the driving method of the imaging device is automatically set. It is configured to change to 1/2 thinning or no thinning.

  Or, by setting the mode for transferring the video signal to the external device (mode selection means), the driving method of the image pickup device is automatically decimated or not decimated when the mode is set to the external output mode. You may comprise so that it may change into.

  Note that the external output connection here includes not only a case where devices are directly connected via a connector and a cable, but also a state where data can be transmitted and received between devices by infrared communication and other non-contact communication functions.

  Although the connection partner for external output is not always a large screen monitor, the monitor screen of the image display device by external connection is often larger than the screen size of the liquid crystal monitor 40 attached to the digital camera 20. Therefore, there is an advantage that high-definition images can be observed at such times.

  As described above, the digital camera 20 of this example automatically switches the reading drive method of the imaging device according to the camera mode and situation, such as normal shooting mode, macro mode, external output, and AE / AF. ing.

  Further, instead of or in addition to the above-described automatic switching of the driving method of the imaging device, a high-quality confirmation mode may be separately provided so that the user can freely select a device reading driving method. That is, when the high image quality confirmation mode is selected, the driving is performed unconditionally without half thinning or thinning. By adding such a high image quality confirmation mode, the user can arbitrarily select whether to view a high-definition image even if the refresh rate is slow or to view an image with a high refresh rate even if the image is somewhat coarse. You can choose.

  According to the digital camera 20 according to the present embodiment, even when the high-pixel solid-state image sensor 28 is mounted, the refresh rate is high and the battery consumption is low during daily use or AE / AF. When ¼ decimation or 1/8 decimation is performed and macros are confirmed or when images are output and confirmed externally, high-capacity imaging with less (or no) decimation is performed. A fine image can be seen.

  In the above embodiment, the digital camera has been described as an example. However, the imaging device driving method according to the present invention is widely applied to electronic cameras (imaging apparatuses) that electrically acquire image signals in addition to digital cameras. be able to.

  In the above embodiment, 1/4 or 1/8 is used as a value corresponding to the first ratio, and 1/2 is described as the second, third, and fourth ratios. The ratio is not limited to these numerical values, and can be freely determined in relation to the number of pixels of the imaging device.

Schematic diagram showing an example of normal drive of an imaging device It is explanatory drawing which shows the example of 1/2 thinning drive of an imaging device, (a) is a figure which shows a 1st example, (b) is a figure which shows a 2nd example. It is explanatory drawing which shows the example of 1/4 thinning drive of an imaging device, (a) is a figure which shows a 1st example, (b) is a figure which shows a 2nd example. It is explanatory drawing which shows the example of 1/8 thinning drive of an imaging device, (a) is a figure which shows a 1st example, (b) is a figure which shows a 2nd example. The block diagram which shows the structure of the digital camera which concerns on embodiment of this invention Block diagram used to explain the signal flow when the refresh rate of the imaging device is matched to a format such as NTSC Explanatory drawing which shows the imaging device drive and monitor display method in macro photography mode Explanatory drawing which shows the other method of imaging device drive and monitor display at the time of macro photography mode Explanatory drawing which shows the relationship between the imaging area and display area at the time of using the method shown in FIG. Explanatory drawing which shows further another method of imaging device drive and monitor display in macro photography mode

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Imaging device 12 ... Photoelectric conversion element (pixel)
DESCRIPTION OF SYMBOLS 14 ... Vertical transfer path 16 ... Horizontal transfer path 28 ... Solid-state image sensor (imaging device)
40 ... LCD monitor 46 ... Control circuit 48 ... Central processing unit (CPU)
50. Operation unit

Claims (2)

In an electronic camera that images a subject using an imaging device in which photoelectric conversion elements are two-dimensionally arranged,
Image display means for displaying an image acquired by the imaging device;
An output terminal for connecting external devices,
Detecting means for detecting that an external device is connected to the output terminal;
In the normal shooting mode in which the external device is not connected to the output terminal, the signal is read out by thinning the vertical direction of the imaging device to the first ratio, and the connection of the external device to the output terminal is detected by the detection means. In such a case, the signal is read out by thinning out the vertical direction of the imaging device to a second ratio that is less thinned than in the normal photographing mode, or the signal is read out for all pixels without performing thinning. Drive control means for driving the imaging device;
An electronic camera characterized by comprising: In an electronic camera that images a subject using an imaging device in which photoelectric conversion elements are two-dimensionally arranged,
Image display means for displaying an image acquired by the imaging device;
An external output means for sending a video signal acquired via the imaging device to an external device;
To perform an operation of selecting one of a normal shooting mode in which the video signal is not transferred to the external device by the external output unit and an external output mode in which the video signal is transferred to the external device by the external output unit. Mode selection means,
When the normal photographing mode is selected by the mode selection unit, a signal is read by thinning out the vertical direction of the imaging device to a first ratio, and when the external output mode is selected by the detection mode selection unit Reads out the signal by thinning out the vertical direction of the imaging device to a second rate that is less thinned than in the normal photographing mode, or reads out the signal for all pixels without performing thinning out. Drive control means for driving;
An electronic camera characterized by comprising:

Images