JP2015154401A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus that reduces blurring of images at the time of photography with light emission.SOLUTION: An imaging apparatus includes: an imaging element 6 for imaging object light; a lighting device 34 that emits illuminating light to a subject; a camera-shake detection section 48 that detects camera-shake; a synchronization speed determination section 4 that determines a synchronization speed of a shutter 38 to be synchronized with light emission of the lighting device based on a camera-shake amount detected by the camera-shake detection section; a decimation rate determination section 4 that determines a decimation rate for reading out an image data from the imaging element based on a synchronization speed determined by the synchronization speed determination section; a photographing control section 4 that allows the lighting device to emit light in synchronization with the synchronization speed determined by the synchronization speed determination section, and allows the imaging element to perform decimation-image photography with light emission at a decimation rate determined by the decimation rate determination section.

Description

  The present invention relates to an imaging apparatus that performs photographing (illumination photographing) with illumination light (light emission).

  2. Description of the Related Art Conventionally, in order to prevent overexposure during backlight photographing, there is an imaging device that thins out the number of pixels and synchronizes with the emission of illumination light to speed up the synchronization time (for example, Patent Document 1). reference).

JP 2003-333419 A

  By the way, since underwater is darker than on land, light emission (illumination) photography that emits illumination light may be performed. However, in flash photography, illumination light is emitted when the shutter is fully opened and the entire screen is illuminated (in the case of shooting at the so-called flash synchronization speed). There was an area that did not go well enough. Also, underwater photography has a problem that the captured image is likely to be blurred in light emission photography in which the shutter speed cannot be increased because the imaging device cannot be fixed due to the floating state of water or the influence of waves.

  An object of the present invention is to provide an imaging apparatus that reduces image blurring during flash photography.

  An imaging apparatus according to the present invention includes an imaging device that captures subject light, an illumination device that emits illumination light to the subject, a camera shake detection unit that detects camera shake, and a camera shake amount detected by the camera shake detection unit. Based on the tuning second time determining unit for determining the second synchronizing time of the shutter to be synchronized with the light emission of the illumination device, and reading out the image data from the imaging device based on the second tuning time determined by the second tuning time determining unit. A decimation rate determination unit for determining a decimation rate at the time, and illuminating the illumination device in synchronization with the synchronization time determined by the synchronization second time determination unit, and the imaging according to the decimation rate determined by the decimation rate determination unit And a photographing control unit that performs thinning image light-emission photographing with an element.

  According to the present invention, it is possible to reduce image blurring during light emission (illumination) photography.

1 is a block diagram showing a system configuration of a digital camera according to an embodiment. It is a flowchart which shows the thinning image light emission imaging | photography process by the digital camera which concerns on embodiment. It is a figure which shows the relationship between opening / closing of the shutter of the digital camera which concerns on embodiment, and light emission of illumination light. It is a figure which shows the thinning-out rate corresponding to the restriction | limiting at the time of the tuning second which concerns on embodiment. It is a figure which shows light emission and the light-receiving area of illumination light when thinning-out image light emission photography is performed in the embodiment. It is a figure which shows light emission and the light-receiving area of illumination light when the imaging | photography range in embodiment is reduced and thinning image light emission imaging | photography is performed.

  Hereinafter, a digital camera as an imaging device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a system configuration of a digital camera 2 according to the embodiment. As shown in FIG. 1, the digital camera 2 includes a control unit 4 that is configured by a microprocessor or the like and comprehensively controls each unit of the digital camera 2. The control unit 4 includes an image sensor 6, an image processing unit 8, a buffer memory 10, an operation unit 12, an external storage unit 14, a display unit 16, a drive unit 18, a light emission control unit 20, a pressure sensor 22, a thinning determination unit 24, The AF control unit 26, the exposure control unit 28, the light control unit 30, the storage unit 31, and the communication unit 32 are connected.

  The image sensor 6 is configured by a CCD, a CMOS, or the like, images subject light via the photographing lens 42, and outputs an image signal to the control unit 4. The image processing unit 8 performs image processing such as white balance adjustment, contour compensation, gamma correction, and resizing processing on the image data based on the imaging signal. The image processing unit 8 performs an interpolation process for interpolating the thinned pixels when the image pickup signal obtained by performing the pixel thinning by the image pickup device 6 is read. The buffer memory 10 temporarily stores image data based on the imaging signal output from the imaging element 6. The operation unit 12 includes a power switch for turning on / off the power of the digital camera 2, a shooting mode button, a release button, and the like.

  The external storage unit 14 is a memory card or the like that is detachably attached to a card slot (not shown) provided in the digital camera 2, and associates image data stored in the buffer memory 10 and information related to imaging. Remember. The display unit 16 is configured by an LCD or the like, and displays a through image based on an imaging signal from the image sensor 6, an image based on image data stored in the external storage unit 14, a menu screen for performing various settings, and the like. . The drive unit 18 opens and closes the shutter 38 according to the release operation.

  Note that the shutter 38 is a mechanical shutter having a front curtain and a rear curtain as a light shielding member, and at the time of photographing, the imaging surface is opened from a state where the front curtain shields the light receiving area of the image sensor 6. After a lapse of time corresponding to a preset shutter speed, the rear curtain travels from a state where the light receiving area is opened to a state where the light receiving area is blocked.

  The light emission control unit 20 controls the light emission timing of the illumination device 34 that emits illumination light for illuminating the subject based on an instruction from the control unit 4. The pressure sensor 22 detects water pressure and the like acting on the digital camera 2. The thinning determination unit 24 determines whether to perform pixel thinning based on a determination result of whether or not the device is used in water based on the detection result of the pressure sensor 22.

  The AF control unit 26 transmits a control signal for moving the focus lens to an appropriate target position to the lens unit 40 by the phase difference AF method or the contrast AF method. Based on the brightness of the subject measured by a photometric sensor (not shown), the exposure control unit 28 determines the shutter speed, aperture value, and ISO sensitivity so that the subject can be photographed with appropriate exposure. The dimming control unit 30 controls the amount of illumination light emitted by the illumination device 34.

  The storage unit 31 stores a table for determining a thinning rate when performing pixel thinning out from the image pickup device 6 and reading out an image pickup signal according to the synchronization time of the shutter 34 to be synchronized with light emission of the illumination device 34.

  The communication unit 32 transmits a control signal or the like to the lens unit 40 in accordance with an instruction from the control unit 4, receives various data transmitted from the lens communication unit 50 of the lens unit 40, and receives the received various types of data. Data and the like are output to the control unit 4.

  The digital camera 2 has a lens mounting portion (not shown) to which the lens unit 40 can be attached and detached, and the lens unit 40 is mounted on the lens mounting portion of the digital camera 2. The lens unit 40 includes a photographic lens 42 and a lens control unit 44 that is configured by a microprocessor or the like and comprehensively controls each unit of the lens unit 40. The lens control unit 44 is connected with a drive unit 46, a camera shake detection unit 48, and a lens communication unit 50.

  The drive unit 46 adjusts the opening amount of the diaphragm 54 for adjusting the amount of light incident on the image sensor 6 in accordance with an instruction from the lens control unit 44. The camera shake detection unit 48 includes a gyro sensor or the like, and detects the presence or absence of camera shake and the amount of camera shake. The lens control unit 44 communicates with the digital camera 2 via the lens communication unit 50.

  Hereinafter, with reference to the flowchart of FIG. 2, the thinned-out image emission photographing process when photographing a still image underwater by the digital camera 2 according to the embodiment will be described.

  When the photographer sets a light emission (illumination) shooting mode in which shooting is performed by causing the illumination device 34 to emit light using the operation unit 12, the control unit 4 shifts to the light emission shooting mode and starts a light emission (illumination) shooting process. . That is, when the release button is pressed, the control unit 4 detects the pressure acting on the digital camera 2 by the pressure sensor 22, and determines whether or not the sensor is being used underwater from the detection result (step S1). When it is determined that the controller 4 is used underwater (Yes in step S <b> 1), the controller 4 acquires camera shake information indicating the presence or absence of camera shake from the lens unit 40 via the communication unit 32. Specifically, the lens control unit 44 detects the presence / absence of camera shake and the amount of camera shake using the camera shake detection unit 48, and if there is no camera shake, the camera shake information indicating that there is no camera shake is transmitted to the digital camera 2 via the lens communication unit 50. If there is a camera shake, the camera shake information to which the camera shake amount is added is transmitted to the digital camera 2 via the lens communication unit 50. Accordingly, the control unit 4 acquires camera shake information.

  When the acquired camera shake information indicates that there is no camera shake (step S2, No), or when the controller 4 determines that the camera is used on land in step S1 (step S1, No), the exposure control unit 28. APEX calculation (with tuning time limit) is performed (step S3), and the shutter time (TV value), aperture value (AV value), and ISO sensitivity (SV value) for proper exposure are determined. In the APEX calculation (with tuning time limit), the shutter time is determined to be equal to or longer than the tuning time (1/60 seconds) for synchronizing with the light emission of the lighting device 34.

  The controller 4 sets the shutter time, aperture value, and ISO sensitivity based on the determined shutter time (TV value), aperture value (AV value), and ISO sensitivity (SV value), and the illumination device 34. Is emitted, and normal flash photography is performed in which imaging is performed by the image sensor 6 (step S4). Note that the control unit 4 controls the light emission control unit 20 at the start of processing for performing flash photography and performs monitor light emission by the illumination device 34. At this time, the light control unit 30 is controlled based on the amount of light incident on the imaging device 6. Thus, the amount of light emitted during the main light emission by the lighting device 34 is determined.

  In normal flash photography, as shown in FIG. 3, the illumination device 34 emits light at the timing when the entire light-receiving area of the image sensor 6 is opened before the front curtain of the shutter 38 opens and the rear curtain travels. A photographed image that has been illuminated is picked up. The control unit 4 stores the image data read from the image sensor 6 and stored in the buffer memory 10 in the external storage unit 14 (step S5).

  On the other hand, when the camera shake amount is added to the camera shake information acquired in step S2, that is, when the camera shake information indicates presence of camera shake (Yes in step S2), the control unit 4 performs an APEX calculation ( Variable time limit) is performed (step S6). The shutter time (TV value), aperture value (AV value), and ISO sensitivity (SV value) are determined.

  Here, the variable tuning second time limit is to change the tuning second time limit so that the shutter second time can be set faster than 1/60 second according to the amount of camera shake. The limit is changed to, for example, 1/125 second, 1/250 second, 1/500 second, or 1/1000 second. Therefore, in step S6, the control unit 4 changes the limit of the tuning time so that the shutter time (TV value) that can eliminate camera shake can be determined, and performs the APEX calculation to obtain the shutter time (appropriate exposure). TV value), aperture value (AV value) and ISO sensitivity (SV value) are determined.

  Next, the control unit 4 refers to the table stored in the storage unit 31 and determines the thinning-out rate of the image data corresponding to the changed limitation on the tuning seconds (step S7). FIG. 4 shows a table stored in the storage unit 31. When the limit at the tuning time is 1/60 seconds, no thinning is performed, and when the limitation at the tuning time is 1/125 seconds, the thinning rate is 3/4. (Throughout one line pixel, one line pixel is thinned out). When the tuning time limit is 1/250 second, the thinning rate is 2/3 (out of three line pixels, one line pixel is thinned out.) The thinning-out rate is 1/2 (one line of pixels is thinned out of two lines of pixels) when the limit at the tuning time is 1/500 seconds. Further, the thinning-out rate is 1/2 when the limit at the tuning time is 1/1000 second. This is because interpolation processing of image data becomes difficult if the thinning rate becomes too large.

  When the determined thinning rate is 3/4 (step S8, small), the control unit 4 emits light from the illumination device 34 and captures a thinned image with a thinning rate of 3/4 at the shutter time determined in step S6. Thinned image emission photography (small thinning rate) is executed (step S9). In this case, the limitation on the tuning time is changed to 1/125 seconds, but by setting the thinning rate to 3/4, illumination light is applied to the entire light receiving area of the image sensor 6 as shown in FIG. Can be taken.

  When the determined thinning rate is 2/3 (step S8, middle), the control unit 4 emits light from the illumination device 34, and captures a thinned image with a thinning rate 2/3 at the shutter time determined in step S6. Thinned image emission photographing (during a thinning rate) is executed (step S10). In this case, the limitation on the tuning time is changed to 1/250 seconds. However, by setting the thinning rate to 2/3, it is possible to perform photographing with illumination light applied to the entire light receiving area of the image sensor 6. .

  When the determined decimation rate is ½ (step S8, large), the control unit 4 determines whether or not to reduce the shooting range by the image sensor 6 depending on whether or not the limitation on the tuning time is 1/500 seconds. Is determined (step S11). For example, the control unit 4 determines that the shooting range is not changed when the limit at the time of synchronization is 1/500 second (No in step S11).

  Further, the control unit 4 determines that the shooting range is to be reduced when the limit of the synchronization time is 1/1000 second (step S11, Yes), and the reduced shooting range (light receiving area) as shown in FIG. Is set (step S12). In other words, the light receiving area is set so that the illumination light strikes the entire area of the reduced imaging range of the image sensor 6 even when the emission time is set to 1/1000 second and the thinning rate is reduced to 1/2. to shrink.

  The control unit 4 emits the illumination device 34 when the limitation on the synchronization time is 1/500 second and it is determined that the shooting range is not changed (No in step S11) or after the shooting range is set in step S12. Then, a thinned-out image emission photographing (thinning-out rate is large) is performed to capture a thinned-out image with a thinning rate of 1/2 at the shutter time determined in step S6 (step S13). In thinning-out image emission photographing (thinning-out ratio is large), when the limit at the time of synchronization is 1/500 second, photographing is performed with illumination light applied to the entire light receiving area of the image sensor 6 by halving the thinning-out ratio be able to. In addition, when the limit of the synchronization time is 1/1000 second, the shutter light is a shutter time that can eliminate camera shake by reducing the photographing range, and illumination light is applied to the entire light receiving area of the image sensor 6 as shown in FIG. Can be taken. In other words, when a thinned image is captured by limiting the synchronization time of 1/500 seconds with a thinning rate of 1/2, if camera shake remains, the shooting range is reduced to 1/500 seconds. Faster tuning time limit is possible.

  The control unit 4 performs an interpolation process for interpolating the image data thinned out by the thinned image emission photographing by the image processing unit 8 (step S14). The control unit 4 stores the image data subjected to the interpolation processing in the external storage unit 14 (step S5).

  According to the digital camera 2 according to this embodiment, thinning-out image emission shooting is performed by determining the thinning-out rate of pixels according to the amount of camera shake when used underwater, and thus light emission with reduced image blurring at the time of shooting is performed. Shooting can be performed.

  In the above-described embodiment, the case where thinned image emission photographing is performed in water has been described as an example. However, when the digital camera 2 is used on land, for example, when photographing outside scenery while moving by car. For example, the thinned image emission photographing according to the above-described embodiment may be performed, and the same effect as described above can be obtained.

  In the above-described embodiment, the case of taking a still image by thinning image emission shooting has been described as an example. However, the present invention may be applied to the case of shooting a moving image by thinning image emission shooting. In this case, the limit and the thinning-out rate at the tuning time are determined based on the amount of camera shake, and the charge accumulation time in the image sensor 6 corresponding to the limitation at the tuning time is set. As a result, even when the illumination device 34 continuously emits light underwater to capture a moving image, illumination light can be applied to the entire image for each frame image, and blurring of the image for each frame image can be reduced. .

  DESCRIPTION OF SYMBOLS 2 ... Digital camera, 4 ... Control part, 6 ... Image pick-up element, 8 ... Image processing part, 14 ... External storage part, 20 ... Light emission control part, 22 ... Pressure sensor, 24 ... Thinning-out judgment part, 28 ... Exposure control part, DESCRIPTION OF SYMBOLS 31 ... Memory | storage part, 34 ... Illuminating device, 38 ... Shutter, 40 ... Lens unit, 44 ... Lens control part, 48 ... Camera shake detection part.

Claims (4)

An image sensor for imaging subject light;
An illumination device that emits illumination light to a subject;
A camera shake detector for detecting camera shake;
Based on the amount of camera shake detected by the camera shake detection unit, a synchronization time determination unit that determines the synchronization time of the shutter to be synchronized with the light emission of the illumination device;
A decimation rate determining unit that determines a decimation rate when reading out image data from the image sensor based on the synchronized second time determined by the synchronized second time determining unit;
A shooting control unit that causes the illumination device to emit light in synchronization with the tuning time determined by the tuning second time determination unit, and performs thinning image emission shooting with the imaging element at a thinning rate determined by the thinning rate determination unit;
An imaging apparatus comprising:   The imaging apparatus according to claim 1, wherein when the tuning second time determined by the tuning second time determination unit is faster than a predetermined value, a range captured by the imaging element is reduced.   The imaging apparatus according to claim 1, further comprising an image complementing unit that complements image data thinned out by the thinned image emission photographing.   The photographing control unit performs thinning-out moving image emission photographing by thinning out image data of frame images constituting moving image data output from the image sensor at a thinning-out rate determined by the thinning-out rate determining unit. The imaging device according to claim 1, wherein the imaging device is a feature.

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