JP2009171006A - Imaging apparatus and control method of thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of obtaining a blur-free image at an appropriate exposure level in an imaging apparatus having a function of bulb photographing, long-time photographing, or the like, and to provide a control method of the imaging apparatus. <P>SOLUTION: The imaging apparatus has: an imaging section 291 for repeatedly capturing an object image at a set period to output image data; an add operation section 294 for performing an add operation to past image data each time the image data is output and for generating an addition image; an image display section 296 for displaying the addition image; a blur detection section 299 for detecting vibration in the imaging apparatus; and a control section 297 for controlling the temporary stop and start of imaging by the imaging section 291, based on the output signal of the blur detection section 299. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and a method for controlling the imaging apparatus, and more specifically, an imaging apparatus and an imaging apparatus capable of confirming the progress of exposure by displaying an image of a subject during execution of bulb photography or long-time photography. The present invention relates to an apparatus control method.

  In general, when shooting a subject such as a starry sky, fireworks, or a night view, bulb shooting is often used. In this bulb photography, an appropriate exposure time, that is, a time from opening the shutter to closing the shutter differs depending on the photographing object and surrounding conditions, and the exposure time must be determined by the photographer himself / herself. For this reason, if the determination is made incorrectly, the photo will be underexposed or overexposed.

Therefore, it is convenient to determine the exposure time if the exposure level can be observed in real time during bulb photography or the like. For example, Patent Document 1 discloses an imaging apparatus that takes out pixel signals from an imaging element at a predetermined time interval (for example, 1/10 second) during an imaging operation and displays sequentially added images on a liquid crystal monitor. Yes. According to this imaging apparatus, the exposure level can be confirmed almost in real time even during bulb photography or long-time photography, and a major failure can be prevented even in bulb photography.
JP 2005-117395 A

  However, bulb exposure often involves long exposure, and the fixing method is poor, and an imaging device such as a camera may move, or the foot may hit the tripod while it is attached to the tripod. When such vibrations are transmitted to the imaging device, a blurred image is generated, which may result in a shooting result different from the original aim.

  The present invention has been made in view of such circumstances, and an imaging apparatus capable of obtaining an image with an appropriate exposure level without blurring in an imaging apparatus having functions such as bulb photography and long-time photography. It is another object of the present invention to provide a method for controlling an imaging apparatus.

  In order to achieve the above object, an imaging apparatus according to a first aspect of the present invention includes an imaging unit that repeatedly captures a subject image at a set cycle and outputs image data, and a past image every time the image data is output. Based on the output signal of the addition detection unit that performs addition calculation with data and generates an addition image, the image display unit that displays the addition image, the shake detection unit that detects the vibration of the imaging device, and the shake detection unit And a control unit for controlling the stop and start of the image pickup by the image pickup unit temporarily.

In the imaging apparatus according to a second aspect, in the first aspect, the control unit is configured to determine a blur amount for temporarily stopping the imaging, and a blur amount for starting the imaging. It has the 2nd judgment value which judges.
In the image pickup apparatus according to a third aspect of the present invention, in the second aspect, the control unit starts the image pickup when the control unit is below the second determination value for a predetermined time.
Furthermore, in the imaging apparatus according to a fourth aspect of the present invention, in the first aspect, the control unit invalidates the image data acquired within the set cycle when the imaging is paused. To do.

An imaging apparatus according to a fifth aspect of the present invention repeatedly captures a subject image at a set cycle, outputs an image data, and performs an addition operation on the repeatedly captured image data to generate an added image A calculation unit, a shake detection unit that detects vibrations of the imaging device and outputs an output signal, and a control that temporarily controls stop and start of the imaging by the imaging unit based on the output signal of the shake detection unit A portion.
In the imaging device according to a sixth aspect of the present invention based on the fifth aspect, the control unit has a hysteresis characteristic in the determination value of the output signal of the blur detection unit when the imaging is temporarily stopped and started.

  According to a seventh aspect of the present invention, there is provided a control method for an image pickup apparatus, in which a subject image is repeatedly picked up at a set cycle, image data is output, and each time the image data is output, an addition operation with past image data is performed. And generating the added image data, displaying the added image based on the generated added image data, and temporarily stopping and starting the imaging of the subject image based on the output signal according to the vibration of the imaging device. Control.

  According to the present invention, in an imaging device having functions such as bulb photography and long-time photography, the imaging of the subject image is temporarily stopped and started based on the vibration detection output of the imaging device. It is possible to provide an imaging apparatus and an imaging apparatus control method capable of obtaining an image with an appropriate exposure level without blurring.

  Hereinafter, a preferred embodiment using a digital single lens reflex camera to which the present invention is applied will be described with reference to the drawings. FIG. 1 is an external perspective view of a digital single-lens reflex camera according to an embodiment of the present invention as seen from the back.

  This digital single-lens reflex camera is composed of a camera body 200 and an interchangeable lens 100. On the upper surface of the camera body 200, a release button 21, a shooting mode dial 22, an information setting dial 24, a strobe 50, and the like are arranged. The release button 21 has a first release switch that is turned on when the photographer is half-pressed and a second release switch that is turned on when the photographer is fully pressed. When the first release switch (hereinafter referred to as 1R) is turned on, the camera performs photographing preparation operations such as focus detection, focusing of the photographing lens, and photometry of the subject brightness, and the second release switch (hereinafter referred to as 2R). When the camera is turned on, the camera executes a photographing operation for capturing image data of the subject image based on the output of the image sensor 221 (see FIG. 2).

  The shooting mode dial 22 is an operation member configured to be rotatable. By matching a picture display or a symbol representing the shooting mode provided on the shooting mode dial 22 with an index, the program shooting mode (P) and aperture priority are set. Each shooting mode such as a shooting mode (A), a shutter priority shooting mode (S), a manual shooting mode (M), and a bulb mode (B) can be selected.

  The information setting dial 24 is an operation member configured to be rotatable, and a desired setting value, mode, or the like can be selected by rotating the information setting dial 24 on an information display screen or the like. When the shutter priority shooting mode or the manual shooting mode is selected by the shooting mode dial 22, the shutter time can be set by the information setting dial 24, and a long time of 30 seconds or more can also be set. It is also possible to set an update time for image display during exposure during bulb shooting or long-second shooting. The strobe 50 is a pop-up type auxiliary lighting device. By operating an operation button (not shown), the strobe 50 pops up and can irradiate the subject.

  On the rear surface of the camera body 200, there are a liquid crystal monitor 26, a continuous / single shooting button 27, an AE lock button 28, an up cross button 30U, a down cross button 30D, a right cross button 30R, and a left cross button 30L (these buttons). The cross buttons 30U, 30D, 30R, and 30L are collectively referred to as a cross button 30), an OK button 31, a live view display button 33, an enlarge button 34, a menu button 37, and a playback button 38. . The liquid crystal monitor 26 is a display device that performs live view display, reproduces and displays a captured subject image, and displays shooting information and menus. Further, at the time of bulb photographing or long-time photographing, an image is displayed based on the image signal acquired by the image sensor 221 during the exposure operation. Any liquid crystal display can be used as long as it can perform these displays.

  The continuous shooting / single shooting button 27 is a continuous shooting mode in which continuous shooting is performed while the release button 21 is fully pressed, and a single shooting mode in which one frame is shot when the release button 21 is fully pressed. This is an operation member for switching. The AE lock button 28 is an operation member for fixing the photometric value. Thus, when the luminance of the object to be photographed is measured and then the AE lock button 28 is operated, the photometric value is retained even if the composition is changed, and photographing can be performed without changing the exposure level.

  The cross button 30 is an operation member for instructing the movement of the cursor in the two-dimensional direction of the X direction and the Y direction on the liquid crystal monitor 26. In addition, when reproducing and displaying the subject image recorded on the recording medium 277, It is also used to select a subject image. In addition to providing four buttons for up, down, left, and right, it is possible to replace with an operation member that can be operated in two dimensions, such as a switch that can detect the operation direction in two dimensions, such as a touch switch. It is. The OK button 31 is an operation member for confirming various items selected by the cross button 30, the control dial 24, or the like.

  The live view display button 33 is an operation button for switching from a display screen for information display or the like to a live view display, or from a live view display to a display screen for information display or the like. The live view display is a mode in which the subject image is displayed on the liquid crystal monitor 26 for observation based on the output of the image sensor 221 for recording the subject image, and the information display is set to display shooting information of the digital single lens reflex camera. Therefore, this mode is displayed on the liquid crystal monitor 26. The enlargement button 34 is an operation member for enlarging and displaying a part of the subject image on the liquid crystal monitor 26, and the enlargement position can be changed by operating the cross button 30 described above.

  The menu button 37 is an operation member for switching to a menu mode for setting various modes of the digital single-lens reflex camera. When the menu mode is selected by operating the menu button 37, a menu screen is displayed on the liquid crystal monitor 26. Is done. The menu screen has a plurality of hierarchical structures. Various items are selected with the cross-shaped button 30, and selection is determined by operating the OK button 31. The playback button 38 is an operation button for instructing the liquid crystal monitor 26 to display a subject image recorded after shooting. The image data of the subject stored in a later-described SDRAM (Synchronous Dynamic Random Access Memory) 267 and recording medium 277 in a compression mode such as JPEG is expanded and displayed.

  A recording medium storage lid 40 is attached to the side surface of the camera body 200 so as to be freely opened and closed. When the recording medium storage lid 40 is opened, a loading slot for the recording medium 277 is provided therein, and the recording medium 277 can be detachably loaded into the camera body 200.

  Next, the overall configuration of the digital single-lens reflex camera mainly including the electric system will be described with reference to FIG. In the present embodiment, the interchangeable lens 100 and the camera body 200 are configured separately and are electrically connected by the communication contact 300, but the interchangeable lens 100 and the camera body 200 can also be configured integrally. . The circuit block of the built-in strobe 50 is omitted in FIG.

  Inside the interchangeable lens 100, a photographing optical system 101 for focus adjustment and focal length adjustment, and a diaphragm 103 for adjusting the aperture amount are arranged. The photographing optical system 101 is driven by a lens driving mechanism 107, and the diaphragm 103 is connected to be driven by a diaphragm driving mechanism 109.

  The lens driving mechanism 107 and the aperture driving mechanism 109 are each connected to a lens CPU 111, and the lens CPU 111 is connected to a communication circuit 273 of the camera body 200 via a communication contact 300. The lens CPU 111 controls the inside of the interchangeable lens 100. The lens CPU 111 controls the lens driving mechanism 107 to perform focusing and zoom driving, and also controls the aperture driving mechanism 109 to perform aperture value control. Further, the lens CPU 111 transmits lens-specific information such as an open aperture value and focal length information of the interchangeable lens 100, and focal length and focal position information detected by an optical system position detection mechanism (not shown) to the camera body 200. To do.

  In the camera body 200, a position tilted by 45 degrees with respect to the optical axis of the lens (the lowered position, the subject image observation position) in order to reflect the subject image to the observation optical system, and a subject image to be guided to the image sensor 221. A movable mirror 201 that can be rotated between the jumped up position (the raised position and the retracted position) is provided. Above the movable mirror 201, a focusing screen 205 for forming a subject image is disposed, and above this focusing screen 205, a pentaprism 207 for horizontally reversing the subject image is disposed.

  An eyepiece lens (not shown) for observing the subject image is arranged on the emission side (right side in FIG. 2) of the pentaprism 207, and the photometric sensor 211 is arranged on the side of the pentaprism 207 so as not to interfere with the observation of the subject image. Has been. The photometric sensor 211 is connected to a photometric processing circuit 241, and the output of the photometric sensor 211 is subjected to processing such as amplification and analog-digital conversion by the photometric processing circuit 241.

  Near the center of the movable mirror 201 described above is a half mirror, and on the back surface of the movable mirror 201, a sub mirror 203 for reflecting subject light transmitted through the half mirror portion to the lower part of the camera body 200 is provided. ing. The sub mirror 203 is rotatable with respect to the movable mirror 201. When the movable mirror 201 is flipped up (the position indicated by a broken line in FIG. 2), the sub mirror 203 is rotated to a position that covers the half mirror portion. When in the observation position (lowering position), it is in an open position with respect to the movable mirror 201 as shown.

  This movable mirror 201 is driven by a movable mirror drive mechanism 239. A focus detection sensor 243 is disposed below the sub mirror 203, and an output of the focus detection sensor 243 is connected to a focus detection processing circuit 245. The focus detection sensor 243 is a known phase difference AF that separates the peripheral light beam of the photographic optical system 101 into two light beams in order to measure the defocus amount of the subject image formed by the photographic optical system 101. It consists of an optical system and a pair of sensors.

A focal plane type shutter 213 for controlling the exposure time is disposed behind the movable mirror 201, and this shutter 213 is driven and controlled by a shutter drive mechanism 237. An imaging element 221 is disposed behind the shutter 213 and photoelectrically converts a subject image formed by the photographing optical system 101 into an electrical signal. The imaging element 211 may be a CCD (Charge Coupled Devices) or a CMOS (Complementary).
Needless to say, a two-dimensional image sensor such as Metal Oxide Semiconductor can be used.

  Between the shutter 213 and the image sensor 221, an infrared cut filter / low pass filter 217, which is an optical filter for removing an infrared light component and a high frequency component from a subject light beam, is disposed. Further, a temperature measurement circuit 231 and a blur sensor / blur detection circuit 233 are disposed in the vicinity of the image sensor 221. The temperature measurement circuit 231 measures the ambient temperature in the vicinity of the image sensor 221 using the temperature dependence of the forward current of the diode and outputs a temperature signal corresponding to the ambient temperature. The blur sensor / blur detection circuit 233 includes a blur sensor that detects vibration applied to the camera body 200 and a blur detection circuit that outputs a blur amount based on the output of the blur sensor. As the shake sensor, a known angular velocity sensor, acceleration sensor, or the like is used.

  The image sensor 221 is connected to the image sensor drive circuit 223, and the image sensor drive circuit 223 reads an image signal from the image sensor 221. The image sensor driving circuit 223 is connected to an ADC (Analogue Digital Converter) circuit 225 that performs analog-digital conversion of an image signal. The output of the ADC circuit 225 is connected to the dark current removal circuit 227. The dark current removal circuit 227 is a circuit for removing dark current generated in the image sensor 221 and corrects image data representing the subject image using the dark current generated in the light-shielding region around the image sensor 221. To do.

The dark current removal circuit 227 is an ASIC (Application Specific
Integrated Circuit Application Specific Integrated Circuit) 250 is connected to a data bus 252 in the circuit. The data bus 252 includes a sequence controller (hereinafter referred to as “body CPU”) 251, an image processing circuit 257, a compression / decompression circuit 259, a video signal output circuit 261, an SDRAM control circuit 265, an input / output circuit 271, and a communication circuit 273. A recording medium control circuit 275, a flash memory control circuit 279, and a switch detection circuit 283 are connected.

  The body CPU 251 connected to the data bus 252 controls the operation of this digital single lens reflex camera. The image processing circuit 257 connected to the data bus 252 is a variety of images such as digital amplification (digital gain adjustment processing) of digital image data, color correction, gamma (γ) correction, contrast correction, and live view display image generation. Perform processing. The compression / decompression circuit 259 is a circuit for compressing the image data stored in the SDRAM 267 by a compression method such as JPEG or TIFF, and decompressing the compressed image data. Note that image compression is not limited to JPEG or TIFF, and other compression methods can be applied.

  The video signal output circuit 261 is connected to the liquid crystal monitor 26 via the liquid crystal monitor drive circuit 263. The video signal output circuit 261 is a circuit for converting the image data stored in the SDRAM 267 and the recording medium 277 into a video signal for display on the liquid crystal monitor 26. As shown in FIG. 1, the liquid crystal monitor 26 is disposed on the back surface of the camera body 200. However, the liquid crystal monitor 26 is not limited to the back surface as long as the photographer can observe the image. .

  The SDRAM 267 is connected to the data bus 252 via the SDRAM control circuit 265, and the SDRAM 267 temporarily stores the image data processed by the image processing circuit 257 or the image data compressed by the compression / decompression circuit 259. This is a buffer memory.

  The input / output circuit 271 connected to the image sensor driving circuit 223, the temperature measuring circuit 231, the blur sensor / blur detection circuit 233, the shutter driving mechanism 237, the movable mirror driving mechanism 239, the photometry processing circuit 241, and the focus detection processing circuit 245 The input / output of data with each circuit such as the body CPU 251 is controlled via the data bus 252.

  The communication circuit 273 connected to the lens CPU 111 via the communication contact 300 is connected to the data bus 252 and exchanges data and communicates control commands with the body CPU 251 and the like. A recording medium control circuit 275 connected to the data bus 252 is connected to the recording medium 277 and controls recording of image data and the like on the recording medium 277 and reading of the image data and the like.

  The recording medium 277 can be loaded with any rewritable recording medium such as an xD picture card (registered trademark), a compact flash (registered trademark), an SD memory card (registered trademark), or a memory stick (registered trademark). And is detachable from the camera body 200. In addition, the hard disk may be configured to be connectable via a communication contact.

  The flash memory control circuit 279 is connected to a flash memory 281, and the flash memory 281 stores a program for controlling the operation of the digital single lens reflex camera, and the body CPU 251 stores the program in the flash memory 281. The digital single lens reflex camera is controlled according to the stored program. Note that the flash memory 281 is an electrically rewritable nonvolatile memory.

  1R switch that detects the first stroke (half press) of the release button 21, 2R switch that detects the second stroke (full press), power switch, menu switch linked to the menu button 37, and linked to the shooting mode dial 22 Various switches 285 including a dial switch, a dial switch interlocked with the information setting dial 24, and various switches interlocked with other operation members are connected to the data bus 252 via the switch detection circuit 283.

  Next, a configuration related to image display during exposure in bulb photography or the like will be described with reference to FIG. The control unit 297 includes a body CPU 251 that controls the entire digital single lens reflex camera. The setting unit 298 sets the display update time for confirming the progress of exposure (exposure level) manually by the information setting dial 24 or automatically based on the shooting information at the time of bulb shooting or the like. To do.

  The blur detection unit 299 includes a blur sensor / blur detection circuit 233 and the like, detects vibration applied to the camera body, and outputs the blur amount to the control unit 297. The imaging unit 291 includes the above-described imaging element 221, imaging element driving circuit 223, ADC circuit 225, dark current removal circuit 227, and the like, and outputs image data based on the image signal in accordance with a control signal from the control unit 297. The output of the imaging unit 291 is connected to the addition operation unit 294.

  The addition operation unit 294 performs addition operation on images acquired every predetermined time during bulb shooting or long-time shooting, and generates added image data. Temporary storage unit 293 is configured by a temporary storage device such as SDRAM 267, temporarily stores the added image data calculated in addition operation unit 294, and stores the added image data already stored in accordance with a control command from control unit 297. The data is supplied to the addition calculation unit 294 and newly added image data is stored again. The addition calculation unit 294 includes a body CPU 251 and an image processing circuit 257, and performs addition calculation between the addition image data already stored in the temporary storage unit 293 and the latest image data in accordance with a control command from the control unit 297. .

  The addition image recording unit 295 is configured by a recording medium such as the recording medium 277 described above, and the final addition image data obtained by the addition operation by the addition operation unit 294 is transferred from the temporary storage unit 293 according to the control command of the control unit 297. Read and store. The image display unit 296 is configured by the liquid crystal monitor 26, the liquid crystal monitor drive circuit 263, and the like, and is controlled by the control unit 297 every time the added image data added by the addition calculating unit 294 is updated and stored in the temporary storage unit 293. According to the instruction, it is read from the temporary storage unit 293 and displayed.

  Since it is configured in this manner, first, the photographer sets the update time by operating the setting unit 298. The control unit 297 performs control so that the image data acquired by the imaging unit 291 is sequentially added by the addition operation unit 294 for each set update time, and the added image is displayed on the image display unit 296. As shown in FIG. 12, since the image data is cumulatively added as shown in FIG. 12, this added image is initially a dark image as shown in FIG. 14 (a), but gradually changes to a bright image and is repeated many times. When the images are cumulatively added, an overexposed image is obtained as shown in FIG.

  During imaging by the imaging unit 291, vibration applied to the camera is detected by the shake detection unit 299, and the shake amount at this time is output to the control unit 297. The control unit 297 temporarily stops the imaging by the imaging unit 291 when the blur amount becomes larger than a predetermined value, and resumes the imaging by the imaging unit 291 when the blur amount becomes smaller than the predetermined value. In one embodiment of the present invention, there are two predetermined values, a first predetermined value and a second predetermined value, in order to provide hysteresis characteristics when temporarily stopping and restarting imaging.

  Next, details of the operation of the digital single-lens reflex camera in one embodiment of the present invention will be described with reference to the flowcharts shown in FIGS. FIG. 4 shows a power-on reset operation by the body CPU 251 on the camera body 200 side. When a battery is loaded in the camera body 200, this flow starts, and it is determined whether the power switch of the camera body 200 is on (# 1).

  If the result of the determination is that the power switch is off, it enters a sleep state that is a state of low power consumption (# 3). In this sleep state, interrupt processing is performed only when the power switch is turned on, and processing for turning on the power switch is performed in step # 5 and subsequent steps. Until the power switch is turned on, operations other than power switch interrupt processing are stopped to prevent the power battery from being consumed. In step # 1, if the power switch is on, or if the sleep state is canceled in step # 3, power supply is started (# 5).

  Next, if there is information such as the shooting mode set by the shooting mode dial 22, the ISO sensitivity set by the information setting dial 24, the manually set shutter speed or aperture value, those shooting conditions, and lens information Reading is performed (# 7). The lens information is read from the lens CPU 111 via the communication circuit 273 such as lens-specific information such as the full aperture value and focal length information of the interchangeable lens 100. In this step, when the valve mode is set or the long shutter speed is set as the shutter speed, these pieces of information are read.

  Subsequently, it is determined whether or not the valve mode is set (# 9). Since the shooting mode is read in step # 7, it is determined whether or not the bulb mode is set as the read shooting mode. As a result of the determination, if the bulb mode is not set, photometry / exposure amount calculation is performed (# 11). In this step, the subject brightness is measured by the photometric sensor 211, an exposure amount is calculated, and exposure control values such as a shutter speed and an aperture value are calculated according to the shooting mode and shooting conditions using the exposure amount.

  If the valve mode is set as a result of the determination in step # 9, an update time (cycle for repeatedly outputting image data) is input (# 31). The input of the update time will be described later with reference to FIG. When the input of the update time is finished, the process jumps to step # 13. In the bulb mode, since the shutter 213 is opened and closed by a user operation regardless of photometry, the photometry / exposure amount calculation in step # 11 is not executed.

  Next, shooting information is displayed on the liquid crystal monitor 26 (# 13). The shooting information includes the shooting mode and shooting conditions read in step # 7, and the shutter speed and aperture value exposure control values calculated in step # 11. When the bulb mode is set as the shooting mode, as shown in FIG. 12, a valve mode display 301 and an update time display 302 are displayed on the liquid crystal monitor 26 together with other shooting information.

  Once the shooting information is displayed, it is next determined whether or not the playback switch linked to the playback button 38 is on (# 17). The reproduction mode is a mode in which image data recorded on the recording medium 277 is read and displayed on the liquid crystal monitor 26 when the reproduction button 38 is operated. If the result of determination is that the regeneration switch is on, regeneration operation is executed (# 33).

  If the result of determination in step # 17 is that the playback switch is not on, it is determined whether or not the menu switch linked to the menu button 37 is on (# 19). In this step, it is determined whether the menu button 37 is operated and the menu mode is set. If the result of determination is that the menu switch is on, a menu is displayed on the liquid crystal monitor 26 and menu setting operation is performed (# 35). Various setting operations such as AF mode, white balance, ISO sensitivity setting, and drive mode setting can be performed by the menu setting operation.

  If the result of determination in step # 19 is that the menu switch is not on, it is determined whether or not the release button 21 has been half-pressed, that is, whether or not the 1R switch is on (# 21). If the result of determination is that the 1R switch is on, a shooting operation subroutine for shooting preparation and shooting is executed (# 37). Details of this subroutine will be described later with reference to FIG.

  If the result of determination in step # 21 is that the 1R switch is not on, it is determined whether or not the power switch is on as in step # 1 (# 23). If the result of determination is that the power switch is on, processing returns to step # 7 and the above operation is repeated. On the other hand, if the power switch is not on, the power supply is stopped (# 25), the process returns to step # 3, and the above-described sleep state is entered.

  Next, the update time input operation in step # 31 will be described with reference to FIG. When this subroutine is entered, first, the ambient temperature in the vicinity of the image sensor 221 measured by the temperature measurement circuit 231 is detected (# 41). When the environmental temperature is obtained, the update time upper limit value is determined based on the environmental temperature (# 43).

  As shown conceptually in FIG. 10, photodiodes (pixels) are arrayed in the two-dimensional direction in the image sensor 221. In FIG. 10, each cell represents a pixel. Most of the pixels of the image sensor 221 are an effective pixel region 311, the right side is a horizontal light-shielded pixel region 312, and the lower side is a vertical light-shielded pixel region 313. Image data is generated based on pixel signals output from pixels belonging to the effective pixel region 311, and dark current data is generated based on pixel signals output from pixels belonging to the horizontal light-shielded pixel region 312 and vertical light-shielded pixel region 313. Is done.

  As shown in FIG. 11, this dark current has temperature dependence, and the dark current (integrated value) increases rapidly with time as the temperature in the vicinity of the image sensor 221 increases. A dark current is superimposed on the pixel signal obtained by photoelectrically converting the subject image output from the image sensor 221. If the exposure time (integration time) becomes longer, the dark current cannot be ignored. Therefore, it is assumed that the dark current output from the horizontal light-shielding pixel region 312 and the vertical light-shielding pixel region 313 is also generated in the effective pixel region 311, and the dark current removal circuit 227 performs dark darkening from image data based on the pixel signal. The dark current is corrected by subtracting the current data.

  The dark current reaches the saturation level earlier as the temperature is higher. When the dark current reaches the saturation level, the dark current cannot be accurately removed. For this reason, in the present embodiment, when performing an exposure operation for a long time such as a bulb mode, the pixel signal is read from the image sensor 221 before the dark current reaches the saturation level. That is, considering the dark current characteristics, the upper limit value of the update time is limited so that the dark current is not saturated based on the environmental temperature measured by the temperature measurement circuit 231 (# 43). Specifically, a table of environmental temperature and upper limit time is stored and determined by referring to this table.

  Next, in order to input the update time, it is determined whether or not the information setting dial 24 has been operated (# 45). If the result of determination is that the information setting dial 24 has not been operated, processing returns to the original routine. On the other hand, if the information setting dial 24 has been operated, the switch detection circuit 283 detects the rotation direction (# 47).

  Subsequently, it is determined whether or not the detected rotation direction is a direction for reducing the update time (# 49). As a result of the determination, if the rotation direction decreases the update time, it is determined whether or not the previous update time has reached the lower limit value (# 51). The lower limit value may be set as appropriate, but may be about 0.1 seconds, for example. If the result of determination is that the lower limit has not been reached, the update time is shortened in a predetermined step in order from the current setting state (# 53). As shown in FIG. 12, the update time is displayed as update display 302 in the shooting information on the liquid crystal monitor 26. For example, each time the information setting dial 24 rotates the update time in a direction to shorten the update time, for example, If the current setting state is the initial value of 30 seconds, it gradually decreases in a predetermined step from FIG. 13 (c) toward the lower limit value in FIG. 13 (a). This step may be appropriately determined in consideration of usability. When the update time is shortened, the original routine is restored.

  If the result of determination in step # 49 is not a decreasing direction, it is determined whether or not the previous update time has reached the upper limit value determined in step # 43 (# 55). If the result of determination is that the upper limit has not been reached, the update time is extended in a predetermined step (# 57). Each time the information setting dial 24 is rotated in a direction to increase the update time, the information setting dial 24 gradually increases in a predetermined step from the current state toward the upper limit value in FIG. The update time intervals in FIGS. 13A to 13E are examples, and can be changed as appropriate.

  Thus, in the present embodiment, the set value is limited so that the update time does not exceed the upper limit value or the lower limit value. For this reason, use exceeding the performance of the image sensor 221 can be prevented. In the present embodiment, the upper limit of the update time is changed according to the dark current characteristics. For this reason, the image data can be corrected according to the dark current, and an image with less noise can be obtained.

  Next, the photographing operation in step # 37 will be described with reference to FIG. This subroutine starts when the 1R switch is turned on. First, the photographing information displayed on the liquid crystal monitor 26 is turned off (# 61). Subsequently, a subroutine for phase difference AF control is executed (# 63). In this subroutine, the focus shift direction and the focus shift amount of the photographing optical system 101 are detected by a known phase difference AF, and the drive control of the optical system drive mechanism 107 is performed based on the focus shift direction and the focus shift amount. The system 101 is focused.

  When the phase difference AF is completed, it is determined whether or not the valve mode is set as in step # 9 (# 65). If the bulb mode is not set as a result of the determination, photometry / exposure amount calculation is performed to determine exposure control values such as shutter speed and aperture value (# 67). On the other hand, if the valve mode is set as a result of the determination, step # 67 is skipped and the process proceeds to step # 69. In the bulb mode, as described above, the opening / closing time of the shutter 213 is determined by the photographer, and photometry and exposure amount calculation are unnecessary.

  Subsequently, it is determined whether the shutter button 21 has been fully pressed, that is, whether the 2R switch is on (# 69). If the result of determination is that the 2R switch is not on, it is determined whether or not the 1R switch is on (# 87). If the result of determination is that the 1R switch is not on, the shooting operation is terminated and processing returns to the original routine. On the other hand, if the result of determination is that the 1R switch is on, processing returns to step # 69 and enters a standby state for detecting the state of the 1R switch and 2R switch.

  If the result of determination in step # 69 is that the 2R switch is turned on, the routine proceeds to step for shooting. First, the movable mirror 201 is retracted (moved to the raised position) (# 71). As a result, the subject light flux by the photographing optical system 101 is guided in the direction of the image sensor 221. Subsequently, the lens CPU 111 is instructed to perform a narrowing operation, and the narrowing operation of the diaphragm 103 is executed (# 73).

  Now that the preparation for entering the normal photographing operation or the bulb photographing operation is completed, the exposure operation is started (# 75). In the exposure, the traveling of the front curtain of the shutter 213 is started and the charge accumulation of the image sensor 221 is started. When the time corresponding to the shutter speed obtained in step # 67 or the shutter speed manually set by the photographer has elapsed, or when the photographer has instructed the end of bulb photography, the running of the rear curtain of the shutter 213 is started. At the same time, the charge accumulation of the image sensor 221 is terminated.

  Here, when the bulb mode is set, the shutter 213 is opened while the release button 21 is fully pressed, and during this time, the image sensor 221 repeatedly acquires image data at update time intervals. An image based on the image data is displayed on the liquid crystal monitor 26 while being updated. Details of this exposure operation will be described later with reference to FIG.

  When the exposure operation is completed, an instruction to open the aperture 103 is output to the lens CPU 111, and the aperture 103 is opened (# 77). Subsequently, the movable mirror 201 is returned to the lowered position (# 79), and image processing of a normal image or additional image data read from the image sensor 221 and temporarily stored in the SDRAM 267 is performed (# 79). # 81). The image data subjected to the image processing is recorded in the recording medium 277 (# 83), and the display of the image displayed on the liquid crystal monitor 26 is stopped (# 85). When the image display is stopped, the original routine is restored.

  Next, the exposure operation in step # 75 will be described with reference to FIG. When this subroutine is entered, first, as in step # 9, it is determined whether or not the valve mode is set (# 101). If the valve mode is not set as a result of the determination, a normal shooting mode such as a program shooting mode is executed.

  As a normal shooting mode, first, a timer for measuring the exposure time is started (# 103), and when the shutter 213 is opened, the image sensor 221 starts imaging (# 105). That is, photoelectric conversion of the subject image formed on the image sensor 221 is performed, and signal charge accumulation is started. It is determined whether the exposure time (set time) corresponding to the shutter speed calculated in step # 67 or manually set has elapsed (# 107). As a result of the determination, when the exposure time has elapsed, the shutter 213 is closed and the imaging with the image sensor 221 is stopped (# 109).

  Subsequently, the image signal is read from the image sensor 221 (# 111), and the read image signal is temporarily stored in the SDRAM 267 (# 113). Based on the temporarily stored image signal, the captured image is displayed on the liquid crystal monitor 26 (# 115).

  If the valve mode is set as a result of the determination in step # 101, first, the update time input in step # 31 is set as a timer for updating time measurement (# 118). Subsequently, the data in the added image storage area (not shown) prepared in the temporary storage unit 293 is cleared (# 119), and a timer for measuring the update time is started (# 120). Next, the blur sensor / blur detection circuit 233 is activated (# 121), and the suspension flag is reset to “0” (# 122). This pause flag is a flag indicating that the imaging operation is paused when the imaging operation is paused, and “1” indicates that the imaging operation is paused.

  Once the pause flag is reset, the shutter 213 is opened and imaging is started (# 123), as in step # 105. Then, a blur detection process subroutine is executed (# 124). In this subroutine, based on the output of the blur sensor / blur detection circuit 233, the imaging is temporarily stopped when the blur amount is equal to or greater than the first determination value, and the imaging is resumed when the state equal to or less than the second determination value continues for a predetermined time. This blur detection processing subroutine will be described later with reference to FIG.

  Subsequently, it is determined whether or not the update time measuring timer has passed the update time set in step # 119 (# 125). As a result of the determination, if the update time has not elapsed, it is determined whether or not the release button 21 has been fully pressed, that is, whether or not the 2R switch has been turned off (# 151). When the 2R switch is on and the update time has not elapsed, the process enters a standby state in which step # 125 and step # 151 are repeatedly determined.

  As a result of the determination in step # 125, when the update time has elapsed, the imaging of the image sensor 221 is stopped while the shutter 213 is open, and the image signal is read (# 127, # 129). The digitized image data of the read image signal is temporarily stored in the latest image holding area in the storage area of the temporary storage unit 293. This accumulation temporarily holds the read image data for an addition operation to be executed later.

  Next, the timer for measuring the update time is restarted (# 133), and the image sensor 221 is started to image (# 135). Subsequently, the addition operation unit 294 performs addition operation on the past addition image data stored in the addition image storage area of the temporary storage unit 293 and the above-described latest image (# 137), and again in the temporary storage unit 293. Store in the added image storage area (# 138). The stored added image is displayed on the liquid crystal monitor 26 (# 139), and the process returns to step # 125 to execute the above-described steps.

  When the photographer who has viewed the displayed image determines that the exposure level has reached the intended level and releases the full press of the release button 21, that is, when the 2R switch is turned off, the determination in step # 151 results in The process proceeds from step # 151 to step # 153, and the process proceeds to end the exposure operation. That is, the shutter 213 is closed and the imaging is stopped (# 153), and the image data is read and the image data is temporarily stored (# 155, # 157) as in steps # 129 and # 131. Then, similarly to steps # 137 to # 139, an added image is obtained by the addition operation, and the added image is stored and then displayed (# 159, # 160, # 161). When the added image is displayed, the operation of the blur sensor / blur detection circuit 233 is stopped (# 163), and the process returns to the original routine.

  Thus, every time the update time set in step # 118 elapses (# 125 → Y), imaging with the image sensor 221 is stopped, the image signal is read, and the past stored in the temporary storage area The added image data is added and calculated, and displayed on the liquid crystal monitor 26 as shown in FIG. When the update time elapses for the first time, the exposure time is short, so the entire image is dark. However, the image data is added every time the update time elapses, so that the image gradually becomes brighter. By observing the liquid crystal monitor 26, the photographer can determine whether the brightness intended by the photographer has been achieved.

  Next, the blur detection processing subroutine of step # 124 will be described using the flowchart shown in FIG. When the subroutine for blur detection processing is entered, first, a temporary stop flag is determined (# 171). If the result of determination is that the temporary stop flag is “0”, it is next determined whether or not the amount of blur output from the blur sensor / blur detection circuit 233 is greater than the criterion value 1 (# 173).

  As a result of the determination, if the blur amount is smaller than the determination value 1, the process returns to the original routine. On the other hand, when the blur amount is larger than the determination value 1 (timing t1 in FIG. 9), the image pickup in the image pickup device 221 is temporarily stopped with the shutter 213 opened (# 175), and the image signal is read out. (# 177). Since the read image signal is discarded, reading of the image signal may be omitted and the image pickup unit may be reset if the image pickup unit can be reset without reading the image signal. . The reason why the image signal captured during the update time is discarded is to prevent the image from being blurred and resulting in a shooting result different from the original aim.

  Thereafter, 1 is set in the temporary stop flag (# 179), and the time measuring operation of the timer for updating time is stopped (# 181). Then, display during stop of the imaging operation is performed (# 183). This display is for notifying that the imaging operation has been stopped due to the detection of blurring, and the stopped display 307 is superimposed on the added image on the liquid crystal monitor 26. When the stop display is performed, the original flow is restored.

  If the result of determination in step # 171 is that the temporary stop flag is 1, it is determined whether or not the blur amount is greater than a determination value 2 (# 185). In this case, it is determined that the amount of shake is determined to be greater than the determination value 1 in step # 173 and the pause flag is set to 1, and during the second predetermined time (timed by the timer 2), the amount of shake is set. Waits for the judgment value to become 2 or less. The determination value 2 is smaller than the determination value 1.

  If the result of determination in step # 185 is that the amount of blur is greater than determination value 2 (FIG. 9, between timing t1 and timing t2), the timer 2 starts timing (# 195) and returns to the original flow. Return. On the other hand, as a result of the determination, if the blur amount becomes smaller than the determination value 2 (FIG. 9, timing t2), whether the timer 2 has completed the timekeeping operation, that is, after the blur amount becomes smaller than the determination value 2, It is determined whether or not a predetermined time has passed (# 187).

  If the result of determination in step # 187 is that timer 2 has not completed timekeeping operation, processing returns to step # 185. On the other hand, when the timing operation of timer 2 is completed (FIG. 9, timing t3), the timing operation of the timer for the update time is started (# 189). Further, the image pickup operation of the image pickup device 221 is started with the shutter 213 opened (# 191). Then, the temporary stop flag is reset to 0 (# 193), and the stopped display 307 displayed in step # 183 is erased (# 194) in accordance with the resumption of imaging. When erasing is complete, the original flow is restored.

  As described above, according to an embodiment of the present invention, the shake detection unit 299 that detects vibration of the image pickup apparatus, and the image pickup by the image pickup unit 291 are temporarily stopped and started based on the detection output of the shake detection unit 299. A control unit 297 for controlling is provided. For this reason, a blur-free image can be obtained.

  In the present embodiment, when determining the blur amount, the first and second determination values are provided to provide hysteresis characteristics. For this reason, it is possible to prevent the imaging operation from becoming unstable before and after the determination value, that is, frequently stopping and starting the imaging.

  Furthermore, in the present embodiment, imaging is started only when the amount of blur is smaller than the determination value for a second predetermined time after the temporary stop. For this reason, it is possible to resume the imaging in the bulb photography after the blur is surely settled, and it is possible to prevent a blurred image.

  In the present embodiment, when the valve mode is set, the release button 21 is fully pressed, and the shutter is opened until the full press is released, that is, only while the 2R switch is on, and the imaging operation is performed. Had gone. However, other than this method, for example, the imaging operation is started when the release button 21 is fully pressed (first release operation), and the imaging operation is continued even when the release button 21 is fully released, and again. The imaging operation may be stopped when the release button 21 is fully pressed (second release operation performed after the first release operation).

  Further, in the present embodiment, the pause and restart of the imaging operation at the time of bulb shooting have been described. However, the present invention is not limited to this, and can also be applied to the case of shooting at long seconds. In the case of long-time shooting, in step # 151, it is only necessary to determine whether or not the set long-second time has elapsed, instead of determining the 2R switch.

  Further, in the present embodiment, when the suspension is temporarily performed based on the blur detection result, the liquid crystal monitor 26 is notified by the stop indication 307. However, the present invention is not limited to this, and photography such as bulb photography is being performed. A display element such as an LED may be provided, and another display element may be used, such as turning off the display element during a temporary stop, or may be notified by a sound generation element. Furthermore, in one embodiment of the present invention, during the temporary stop, the stopped display 307 is displayed during the stop, but it may be notified only for a predetermined time from the start of the temporary stop.

  Further, in the present embodiment, when the exposure operation is finished, in step # 155 (FIGS. 7 and 14), an image is read and an added image obtained by adding the images is displayed (# 161). However, it is of course possible to display the final added image obtained in step # 137 without reading out the image in step # 155.

  Further, in this embodiment, the added image is overwritten every time the image is taken. However, a plurality of temporary storage areas are prepared and stored in the plurality of temporary storage areas sequentially without overwriting the added images. Anyway. Further, the update time of the added image is manually input by the photographer using the information setting dial 24 (# 31 in FIG. 4). However, the update time is not limited to this. Of course, it does not matter if it is set automatically.

Furthermore, in the present embodiment, an example in which a single-lens reflex type is applied as a digital camera has been described. However, the present invention may be a digital camera such as a compact type other than a single-lens reflex type, and may be a mobile phone or a personal digital assistant (PDA). Personal
Of course, a camera built into Digital Assist) may be used. The present invention can be applied to any imaging apparatus capable of shooting in bulb mode or long time.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the gist thereof in the implementation stage. . In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, you may delete some components of all the components shown by embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is the external appearance perspective view which looked at the digital single-lens reflex camera concerning one Embodiment of this invention from the back. 1 is a block diagram illustrating an overall configuration of an electric system of a digital single-lens reflex camera according to an embodiment of the present invention. In the digital single-lens reflex camera concerning one Embodiment of this invention, it is the block diagram which extracted and showed the structure relevant to imaging and display, such as a valve mode. It is a flowchart which shows the operation | movement of the power-on reset in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the update time input in one Embodiment of this invention. It is a flowchart which shows the imaging | photography operation | movement in one Embodiment of this invention. It is a flowchart which shows the exposure operation | movement in one Embodiment of this invention. It is a flowchart which shows the blur detection process in one Embodiment of this invention. In the digital single-lens reflex camera concerning one Embodiment of this invention, it is a figure which shows the state change of an imaging according to blurring amount. It is a figure which shows each area | region of the image pick-up element of the digital single-lens reflex camera concerning one Embodiment of this invention. 4 is a graph showing the relationship between temperature and integration level with respect to dark current in an image sensor of a digital single lens reflex camera according to an embodiment of the present invention. It is a figure which shows the imaging | photography information display of the digital single-lens reflex camera concerning one Embodiment of this invention. It is a figure which shows the update display of the digital single-lens reflex camera concerning one Embodiment of this invention, (a) to (e) shows the display of each different update time. It is a figure which shows the image display in the liquid crystal monitor at the time of bulb mode imaging | photography in one Embodiment of this invention, (a)-(g) shows the display which changes with progress of update time.

Explanation of symbols

21 ... Release button, 22 ... Shooting mode dial, 24 ... Information setting dial, 26 ... LCD monitor, 27 ... Continuous / single-shot button, 28 ... AE lock button, 30 ... Cross button, 30U ... Cross button for up, 30D ... Cross button for down, 30R ... Cross button for right, 30L ... Cross button for left, 31 ... OK button, 33 ..Live view display button 34... Enlarge button 37. Menu button 38. Play button 40. Media loading lid 50. Strobe 100. Interchangeable lens 101 ... Imaging optical system, 103. Diaphragm, 107... Optical system drive mechanism, 109... Diaphragm drive mechanism, 111. 203 ... submirror, 205 ... focusin Screen, 207... Pentaprism, 211... Photometric sensor, 213... Focal plane shutter, 217... Infrared cut filter / low pass filter, 221. Circuit 225 ... ADC circuit 227 ... Dark current removal circuit 231 ... Temperature measurement circuit 233 ... Blur sensor / blur detection circuit 237 ... Shutter drive mechanism 239 ... Moving mirror Drive mechanism, 241 ... photometric processing circuit, 243 ... focus detection sensor, 245 ... focus detection processing circuit, 250 ... ASIC, 251 ... sequence controller (body CPU), 252 ... data Bus, 257 ... Image processing circuit, 259 ... Compression / decompression circuit, 261 ... Video signal output circuit, 263 ... Liquid Monitor drive circuit, 265... SDRAM detection circuit, 267... SDRAM, 271... I / O circuit, 273... Communication circuit, 275... Recording medium control circuit, 277. ... Flash memory control circuit, 281 ... Flash memory, 283 ... Switch detection circuit, 285 ... Various switches, 291 ... Imaging unit, 293 ... Temporary storage unit, 294 ... Addition Arithmetic unit, 295 ... addition image recording unit, 296 ... image display unit, 297 ... control unit, 298 ... setting unit, 299 ... blur detection unit, 300 ... communication contact, 301 ... Valve mode display, 302 ... Update time display, 307 ... Stopped display, 311 ... Effective pixel area, 312 ... Horizontal shading pixel area, 313 ... Vertical shading pixel area

Claims (7)

An imaging unit that repeatedly captures a subject image at a set period and outputs image data;
Each time the image data is output, an addition operation unit that performs an addition operation with past image data and generates an added image;
An image display unit for displaying the added image;
A blur detection unit that detects vibration of the imaging device;
A control unit for temporarily stopping and starting the imaging by the imaging unit based on an output signal of the blur detection unit;
An image pickup apparatus comprising:   The control unit has a first determination value for determining a blur amount for temporarily stopping the imaging, and a second determination value for determining a blur amount for starting the imaging. The imaging apparatus according to 1.   The imaging apparatus according to claim 2, wherein the control unit starts the imaging when the value is below the second determination value for a predetermined time.   The imaging apparatus according to claim 1, wherein when the imaging is paused, the control unit invalidates the image data acquired within the set cycle. An imaging unit that repeatedly captures a subject image at a set period and outputs image data;
An addition operation unit that performs an addition operation of the image data repeatedly captured and generates an addition image;
A vibration detection unit that detects vibration of the imaging device and outputs an output signal;
A control unit for temporarily stopping and starting the imaging by the imaging unit based on the output signal of the blur detection unit;
An image pickup apparatus comprising:   The imaging apparatus according to claim 5, wherein the control unit has a hysteresis characteristic in a determination value of the output signal of the shake detection unit when the imaging is temporarily stopped and started. Repeatedly capture the subject image at the set cycle, output the image data,
Each time the image data is output, an addition operation with past image data is performed to generate addition image data,
An added image is displayed based on the generated added image data,
Based on the output signal according to the vibration of the imaging device, the imaging of the subject image is temporarily stopped and controlled to start.
And a method of controlling the imaging apparatus.