JP2010136239A - Photographic apparatus, control method of the photographic apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a saturation region from being multiplexed, when capturing an image in which a subject is stationary and the background is shown flowing. <P>SOLUTION: Prior to main photographing, a pre-image is captured, and the exposure time for a plurality of times of photographing during a panning mode is set from the pre-image. It is determined through photographing, according to the set exposure time whether there is a saturation region in an image. If there is a saturation region, exposure is set to further shorten the exposure time. For the case of positive determination, a plurality of images are captured, by performing a plurality of times of photographing, and the plurality of images are combined, thereby generating a combined image in which a desired subject is stationary and the background is shown flowing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photographing apparatus particularly suitable for panning, a photographing apparatus control method, and a program for causing a computer to execute the photographing apparatus control method.

  When shooting a moving subject such as an automobile to obtain an image with a sense of speed, with the shutter speed set slower than normal, the photographer moves the camera according to the subject's movement, A panning technique is used, which can obtain a still image with a flowing background. Although such a panning shot can obtain a speedy image, it is necessary to move the camera in accordance with the movement of the subject, so there is a high possibility that a moving subject will be shaken unless it is an expert. .

For this reason, at the time of panning, a plurality of images are continuously captured at a shutter speed shorter than the shutter speed when performing normal panning, and a plurality of images are acquired, and positions of moving objects included in the plurality of images A technique for synthesizing a plurality of images and acquiring a synthesized image while performing matching is proposed (see Patent Documents 1 to 3). According to the methods of Patent Literatures 1 to 3, since the shutter speed of each photographing is short, it is possible to reduce blurring of the moving object. As a result, the moving object is similar to the case where the expert performs the panning. Can obtain a composite image in which the background is still and the background is flowing.
JP 2005-135091 A JP 2006-339903 A JP 2006-25312 A

  In the images acquired by the methods described in Patent Documents 1 to 3, the background is a result of superimposing a plurality of images. For this reason, if the saturated area where the pixel value is the maximum value is included in each of the plurality of images, the position of the saturated area moves in the order of photographing, so the position of the saturated area in each image is different. When the positions of the saturated regions are different in this way, there are portions in the composite image where the saturated region and the unsaturated region in each image overlap. However, when the saturated region and the unsaturated region in each image overlap, the saturated region does not flow smoothly, and the saturated region and the unsaturated region appear alternately on the composite image, so there is a saturated region in between. As a result, the saturation region is multiplexed.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent saturation regions from being multiplexed when an image in which a subject is stationary and a background flows is acquired.

An imaging apparatus according to the present invention includes imaging means for acquiring an image by imaging,
Photographing control means for controlling the photographing means to sequentially acquire a plurality of images sequentially in time;
Motion analysis means for analyzing the motion of the plurality of images;
Based on the analysis result of the movement, a combining unit that combines the plurality of images to generate a combined image;
Exposure processing means for setting exposure of the photographing means so that a saturated region does not exist in each of the plurality of images when the plurality of images are acquired using the photographing means. It is.

  “Analyzing the movement of a plurality of images” means analyzing how the pixels in each image are moving. Specifically, using one of the plurality of images as a reference, the movement direction and the movement amount of the corresponding pixel between the reference image and the other images are obtained, and the reference direction is determined based on the movement direction and the movement amount. This means analyzing how the pixels in the image to be moved are moving.

  In the photographing apparatus according to the present invention, the synthesizing unit detects a moving object from each of the plurality of images based on the analysis result of the movement, and the position of the moving object in each of the plurality of images substantially matches. As described above, the plurality of images may be combined to generate a combined image.

  In the photographing apparatus according to the present invention, the exposure processing means may be means for controlling the exposure of the photographing means so that each pixel value of the plurality of images is less than the maximum luminance.

  Further, in the photographing apparatus according to the present invention, a pre-image for controlling the exposure is obtained before obtaining the plurality of images, and the exposure at the time of obtaining the plurality of images is set based on the pre-image, The pre-image is acquired again with the set exposure, it is determined whether or not the saturated region exists in the pre-image, and the setting of the exposure and the acquisition of the pre-image are repeated until the determination is negative. It may be further provided with control means for controlling the photographing control means and the exposure processing means to repeat.

  In addition, the photographing apparatus according to the present invention may further include brightness correction means for correcting the brightness of the composite image.

  Further, in the photographing apparatus according to the present invention, the exposure processing unit may be configured so that the saturation region does not exist in a region other than the region where the motion is small in the plurality of images based on the analysis result of the motion. It is good also as a means to set exposure.

  In the photographing apparatus according to the present invention, the photographing control unit stops acquiring the plurality of images when the saturation region cannot be eliminated even if the exposure set by the exposure processing unit reaches a limit value. It may be a means.

  The “exposure limit value” is a limit for underexposure of at least one of exposure setting values that can be set by the exposure processing means, that is, shutter speed, aperture value, gain, etc., so that there is no saturation region. Mean value. For example, when the fastest shutter speed that can be set in the photographing apparatus is 1/2000 seconds, the exposure limit value is 1/2000 seconds.

  In this case, notification means for notifying that acquisition of the plurality of images has been stopped may be further provided.

An imaging apparatus control method according to the present invention includes an imaging means for acquiring an image by imaging,
Photographing control means for controlling the photographing means to sequentially acquire a plurality of images sequentially in time;
Motion analysis means for analyzing the motion of the plurality of images;
A control method for an imaging apparatus, comprising: combining means for combining the plurality of images to generate a combined image based on the analysis result of the movement,
When the plurality of images are acquired using the photographing unit, exposure of the photographing unit is set so that a saturated region does not exist in each of the plurality of images.

  In addition, you may provide as a program for making a computer perform the control method of the imaging device by this invention.

  According to the present invention, the exposure of the photographing unit is set so that there is no saturated region in each of the plurality of images, and the plurality of images are acquired sequentially in time, based on the motion analysis results of the plurality of images. Thus, a plurality of images are combined to generate a combined image. As a result, the saturated region does not exist in the plurality of images, so that the saturated region and the non-saturated region do not overlap on the composite image, and as a result, the saturation region can be prevented from being multiplexed.

  In addition, by detecting a moving object from each of the plurality of images based on the analysis result of the movement, and generating a composite image by combining the plurality of images so that the positions of the moving objects in each of the plurality of images substantially match, It is possible to obtain an image in which the moving object is accurately stopped and the background flows.

  Further, by controlling the exposure so that each pixel of the plurality of images is less than the maximum luminance, it is possible to reliably prevent the generation of a saturated region.

  Here, when the exposure is set so that there is no saturated region, the plurality of images are underexposed and the brightness is insufficient. Therefore, by correcting the brightness of the composite image, it is possible to acquire a composite image having a desired brightness while preventing the saturation region from being multiplexed.

  In addition, since a region with small motion is stationary in the composite image, multiplexing does not occur in the composite image even if a saturated region exists. For this reason, it is possible to reduce the amount of calculation for setting the exposure by setting the exposure so that there is no saturated region in a region other than the region where the motion is small in the plurality of images.

  In addition, when the exposure becomes the limit value and the existence of the saturated region cannot be resolved, the acquisition of the plurality of images and the generation of the composite image in the situation where the multiplexing occurs are stopped by stopping the acquisition of the plurality of images. It is possible to prevent wasteful processing due to the execution.

  In this case, by notifying that the generation of a plurality of images has been stopped, the photographer can know in advance that a composite image will not be generated even if panning is performed. By taking measures, it is possible to ensure that there are no saturated regions in the image.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are views showing the appearance of a digital camera 1 to which a photographing apparatus according to an embodiment of the present invention is applied. As shown in FIGS. 1 and 2, a release button 2, a power button 3, and a zoom lever 4 are provided on the top of the digital camera 1.

  The release button 2 has a structure in which two types of operations can be instructed by pressing in two steps. For example, in shooting using an automatic exposure adjustment function (AE: Auto Exposure) and an automatic focus adjustment function (AF: Auto Focus), the digital camera 1 performs a first pressing operation (half-pressing) in which the release button 2 is lightly pressed. (Also called exposure), preparation for shooting such as exposure adjustment and focusing is performed. In this state, when a second pressing operation (also referred to as full pressing) in which the release button 2 is strongly pressed is performed, the digital camera 1 starts exposure and records image data for one screen obtained by the exposure. Record on media.

  On the back of the digital camera 1, a monitor 5 such as a liquid crystal, a mode dial 6 used for setting a shooting mode, and various operation buttons 8 are provided. In the present embodiment, it is possible to set a shooting mode for shooting, a playback mode for playing back an image recorded on a recording medium on the monitor 5, and the like. In addition to the normal shooting mode for performing normal shooting, the panning mode for performing panning can be set as the shooting mode.

  Next, the internal configuration of the digital camera 1 will be described. FIG. 3 is a schematic block diagram showing an internal configuration of a digital camera to which the photographing apparatus according to the embodiment of the present invention is applied. As shown in FIG. 3, the digital camera 1 to which the photographing apparatus according to the present embodiment is applied has an imaging system 9.

  The imaging system 9 includes a photographing lens 10 including a focus lens 10a for focusing on a subject and a zoom lens 10b for realizing a zoom function. Each lens can be moved in the optical axis direction by a focus lens driving unit 11 and a zoom lens driving unit 12 each including a motor and a motor driver. The focus lens driving unit 11 controls the movement of each lens based on an instruction from the AF processing unit 28 described later, and the zoom lens driving unit 12 based on an instruction from the CPU 40 according to the operation of the zoom lever 4. .

  The diaphragm 14 includes a plurality of diaphragm blades. The aperture drive unit 15 is a small motor such as a stepping motor, and adjusts the position of the aperture blade so that the aperture size of the aperture becomes a size suitable for the purpose according to the aperture value data output from the AE processing unit 29. .

  The shutter 16 is a mechanical shutter and is driven by a shutter driving unit 17. The shutter drive unit 17 controls the opening and closing of the shutter 16 according to a signal generated by pressing the release button and the shutter speed data output from the AE processing unit 29.

  An image sensor 18 is provided behind the shutter 16. In the present embodiment, it is assumed that a CMOS type image sensor 18 is used. The imaging element 18 has a photoelectric surface in which a large number of light receiving elements are two-dimensionally arranged, and subject light that has passed through an optical system such as the photographing lens 10 forms an image on the photoelectric surface and is subjected to photoelectric conversion. In front of the photocathode, a microlens array for condensing light on each pixel and a color filter array in which filters of R, G, and B colors are regularly arranged are arranged. The image sensor 18 outputs the electric charge accumulated for each pixel as an analog photographing signal one pixel at a time in synchronization with the readout signal supplied from the image sensor controller 19. The time for accumulating charges in each pixel, that is, the exposure time, is determined by an electronic shutter drive signal given from the image sensor control unit 19. This exposure time is set by an AE processing unit 29 described later. The gain of the image sensor 18 is adjusted by the image sensor control unit 19 so that an analog image signal having a predetermined size can be obtained.

  The analog photographing signal read from the image sensor 18 is input to an analog front end (AFE) 20. The AFE 20 includes a correlated double sampling circuit (CDS) that removes noise from the analog signal, an auto gain controller (AGC) that adjusts the gain of the analog signal, and an A / D converter (ADC) that converts the analog signal into a digital signal. It consists of. The image data converted into the digital signal is RAW data having R, G, and B density values for each pixel.

  The timing generator 21 generates a synchronization signal. By supplying this timing signal to the shutter drive unit 17, the image sensor control unit 19, and the AFE 20, the release button is operated, the shutter 16 is opened and closed, and the image sensor 18. The readout of the charges from the AFE 20 and the processing of the AFE 20 are synchronized. The maximum value of the charge reading speed from the image sensor 18 (maximum charge read time) is determined in advance by the specifications of the image sensor 18 and the timing generator 21.

  In addition, the digital camera 1 has a flash 24 that emits light when necessary during photographing. The light emission of the flash 24 is controlled by the light emission control unit 23.

  The digital camera 1 also has an image input controller 25 that transfers the image data output from the AFE 20 to another processing unit via the data bus 41, and a frame memory 26 that temporarily stores the image data transferred from the image input controller 25. Is provided.

  The frame memory 26 is a working memory used when performing various processes described later on image data. For example, an SDRAM (Synchronous Dynamic Random Access Memory) that performs data transfer in synchronization with a bus clock signal having a constant period. Is used.

  The display control unit 27 displays the image data stored in the frame memory 26 on the monitor 5 as a through image, or displays the image stored on the recording medium 34 on the monitor 5 in the reproduction mode. is there. The through image is captured by the imaging system 9 at predetermined time intervals in synchronization with the synchronization signal generated by the timing generator 21 while the imaging mode is selected.

  The AF processing unit 28 and the AE processing unit 29 determine shooting conditions based on the pre-image. The pre-image is represented by image data stored in the frame memory 26 as a result of the CPU 40 having detected a half-press signal generated by half-pressing the release button causing the image sensor 18 to perform pre-photographing. It is an image.

  The AF processing unit 28 detects the in-focus position of the focus lens 10a based on the pre-image. As a method for detecting the in-focus position, for example, a TTL method for detecting the in-focus position using the feature that the contrast of the image is high when the desired subject is in focus is used.

  The AE processing unit 29 measures the subject brightness based on the pre-image, and sets and outputs the aperture value and the shutter speed as the exposure set value based on the measured subject brightness (AE process). Specifically, as shown in FIG. 4, the pre-image is divided into 64 × 8 photometric areas, and the shutters are determined based on the brightness of each area and a program diagram stored in the internal memory 35 in advance. Set the speed and aperture value. The shutter speed corresponds to the exposure time of the image sensor 18.

  Here, in the digital camera 1 according to the present embodiment, when the normal shooting mode is set, shooting is performed by one exposure by pressing the release button once. On the other hand, when the panning mode is set, the exposure is usually divided into a plurality of times, and a plurality of images corresponding to the plurality of exposures are acquired. . Note that a plurality of images are combined as described later to generate a combined image. For this reason, in the panning mode, the AE processing unit 29 sets the exposure time (set as T1) after the division based on the shutter speed set based on the pre-image, that is, the exposure time (set as T0). The number of exposures n is calculated. In the following description, the process of setting the exposure time T0 before setting the exposure time T1, that is, the process of setting the exposure time T0 in the normal photographing mode is performed after the first AE process and the first AE process. The process of setting the exposure time T1 for acquiring a plurality of images in the panning mode is referred to as a second AE process. Note that the second AE process includes the first AE process.

  In the present embodiment, after performing the first AE process, the AE processing unit 29 performs the exposure time T0, the exposure time T1, and the exposure stored in the internal memory 35 described later in the second AE process. With reference to the table in which the number of times n is associated, the exposure time T1 and the exposure time n are set from the exposure time T0. Note that when the image sensor 18 is capable of reading charges for 300 frames per second at the maximum, the maximum charge reading time is 1/300 seconds, so the minimum value of the exposure time T1 is 1/300 seconds. It becomes.

  Here, the maximum readout time of the image sensor 18 means the shortest value of time required to read out the electric charge generated by the exposure after the exposure is completed after the exposure of the image sensor 18 is started. For this reason, when the exposure time of the image sensor 18 is shorter than the maximum readout time, the reading of the charge from the image sensor 18 cannot be continued. However, when the exposure time of the image sensor 18 is equal to or longer than the maximum readout time, the image sensor The reading of charges from 18 can be continued.

  Further, at the time of shooting in the normal shooting mode, the shutter 16 is opened at the shutter speed set by the AE processing unit 29, and the image sensor 18 is exposed for an exposure time T0 corresponding to the shutter speed. On the other hand, at the time of shooting in the panning mode, the shutter 16 is opened after the release button is pressed until the set number of exposures n is taken, and during that time, the image is taken at the set exposure time T1. Charges are repeatedly read from the element 18.

  FIG. 5 is a diagram showing the shutter speed, that is, the exposure time for one shooting in the normal shooting mode, and FIG. 6 is a diagram showing the exposure time for one shooting in the panning mode. As shown in FIG. 5, when the exposure time T0 when the divided shooting is not performed is 1 / 7.5 seconds and the exposure time T1 is 1/60, in the panning mode, the figure is shown. As shown in FIG. 6, the exposure with an exposure time T1 of 1/60 seconds is performed eight times.

  Note that since the exposure time T1 for one shooting in the panning mode is shorter than the exposure time T0, the brightness of an image acquired by one shooting in the panning mode is set to one exposure time T0. In order to match the brightness of an image acquired by shooting, it is necessary to increase the aperture value. For this reason, in the present embodiment, in the panning mode, the aperture value for one shooting is set together with the exposure time T1 by the second AE process. Note that the aperture value set by the first AE process may be used as it is without setting the aperture value.

  The AWB processing unit 30 automatically adjusts the white balance at the time of shooting (AWB processing).

  The image processing unit 31 performs image quality correction processing such as brightness correction, gradation correction, sharpness correction, and color correction on the image data of the main image, and RAW data as Y data that is a luminance signal and a blue color difference signal. YC processing is performed for conversion into YC data consisting of Cb data that is and Cr data that is a red color difference signal. The main image is an image represented by image data that is captured from the image sensor 18 by main shooting executed when the release button is fully pressed and is stored in the frame memory 26 via the AFE 20 and the image input controller 25. It is.

  The compression / decompression processing unit 32 performs a compression process on the image data of the main image processed by the image processing unit 31 in a compression format such as JPEG, and generates an image file. A tag storing incidental information such as shooting date and time is added to the image file based on the Exif format or the like.

  The media control unit 33 accesses a recording medium 34 that is detachably set on a media throttle (not shown), and controls writing and reading of an image file.

  The internal memory 35 stores various constants set in the digital camera 1, a lookup table, a program executed by the CPU 40, and the like.

  The digital camera 1 also includes a motion analysis unit 36 and a synthesis unit 37.

  The motion analysis unit 36 analyzes the motion of the image. Specifically, one reference image is set in a plurality of images acquired by shooting in the panning mode, and the movement direction and movement amount of the corresponding pixel between the reference image and another image are obtained, and the movement direction and movement are determined. Based on the quantity, it is analyzed how the pixels in the reference image are moving. For example, when three images G1 to G3 are acquired by shooting in the panning mode as shown in FIG. 7, if the reference image is the image G1, the movement amount of the pixel corresponding to the car in the reference image G1 is as follows. Since the motion analysis unit 36 is very small, the motion analysis unit 36 outputs an analysis result indicating that the pixel motion in the region corresponding to the automobile in the reference image G1 is small. Note that whether or not the movement is small may be determined by determining whether or not the movement amount is smaller than a predetermined threshold value. On the other hand, since the background house in the reference image G1 has moved greatly, the motion analysis unit 36 outputs an analysis result that the movement of the pixels in the region other than the region corresponding to the car in the reference image G1 is large.

  Note that before the actual photographing, motion analysis may be performed between two through-images acquired successively.

  The combining unit 37 combines a plurality of images acquired by shooting in the panning mode based on the analysis result by the motion analysis unit 36. Specifically, a composite image is generated by superimposing them so that the positions of the regions with small motion in the plurality of images are the same position. For example, if the movement of the central region is small in a plurality of images, a composite image is generated by superimposing the plurality of images so that the position of the central region is the same position. Note that the composition may be performed by calculating the average value of the corresponding pixel values between the plurality of images after aligning the positions of the regions where the motion is small for the plurality of images. Here, the alignment is performed by selecting one reference image from a plurality of images, so that the position of the region where the movement is small in the other image matches the position of the region where the movement included in the reference image is small. May be performed by transforming such as rotation, enlargement / reduction, or the like.

  In addition, based on the analysis result by the motion analysis unit 36, an area where the motion of a plurality of images is small is detected as a moving body, and the plurality of images are superimposed so that the position of the moving body is the same position, and the combined image May be generated.

  As a result, the composite image G0 generated from the three images G1 to G3 as shown in FIG. 7 is such that the automobile is stationary and the background house flows as shown in FIG. Here, in FIG. 8, a state in which an image of a background house is being flown is represented by a horizontal line.

  When shooting using the aperture value set by the first AE process in the panning mode, a composite image is generated by simply adding pixel values of corresponding pixels between a plurality of images. You may make it do.

  By the way, the background of the composite image acquired in the panning mode is a superposition of a plurality of images. For this reason, since the pixel value becomes the maximum value in each of the plurality of images, if the saturated region where the pixel value is saturated is included, the position of the saturated region moves in the shooting order. The positions of are different. When the positions of the saturated regions are different as described above, there are portions where the saturated region and the unsaturated region in each image overlap in the composite image. Here, when the pixel value is saturated, for example, when the pixel value of each pixel of the image acquired by the digital camera 1 according to the present embodiment has a resolution of 8 bits for each color of RGB, each value of RGB becomes 256. .

  However, when the saturated region and the unsaturated region in each image overlap, the saturated region does not flow smoothly, and the saturated region and the unsaturated region appear alternately on the composite image, so there is a saturated region in between. As a result, the saturation region is multiplexed.

  For example, as shown in FIG. 9, when the sunlight is reflected on the window portion of the house of the three images G11 to G13 acquired in the panning mode, that portion becomes a saturated region. When the three images G11 to G13 including the saturated region are combined in this way, as shown in FIG. 10, since the three saturated regions appear in the background of the combined image G10, the saturated regions are multiplexed.

  For this reason, in the present embodiment, before the main shooting, pre-shooting is performed again with one exposure time T1 set in the panning mode, and a saturated region is included in the pre-image acquired by the second pre-shooting. Determine if it exists. If there is no saturated region, shooting is performed with the set exposure time T1. When the saturated region exists, the AE processing unit 29 performs the second AE process again using the pre-image acquired again so that the exposure is under, and sets the exposure time T1 and the number of exposures n again. Set. Then, the pre-photographing and the setting of the exposure time T1 are repeated until the exposure time T1 in which no saturated region exists is set. Note that the second AE process again does not include the first AE process.

  In addition, since a subject with small motion is stationary in the composite image, no multiplexing occurs in the composite image even if a saturated region exists on the subject. For this reason, motion analysis is performed by the motion analysis unit 36 from the time of through-image shooting, and it is determined whether or not a saturated region exists in the pre-image only in a region other than the region in which the motion in the pre-image is small. Also good. For example, as shown in FIG. 11, in the case where the pre-image is divided into 64 areas and AE processing is performed, is a saturated area present in an area (indicated by hatching) other than an area where a car with small movement exists? What is necessary is just to determine.

  In the panning mode, the subject to be photographed so as to be stationary is often at the center of the angle of view. For this reason, you may use the area | region which exists in the center predetermined range among several area | regions divided | segmented for AE processing as an area | region where a motion is small.

  The exposure time T1 is shortened by repeating the setting of the exposure time T1, but in order to continuously read out charges from the image sensor 18, the exposure time is longer than the maximum charge read time of the image sensor 18. T1 cannot be shortened. For this reason, in the present embodiment, if the existence of the saturated region cannot be eliminated even if the exposure time T1 is set to the time corresponding to the maximum charge readout time, the CPU 40 generates the saturation region in the composite image. Since panning cannot be avoided, the panning mode is stopped. Further, the CPU 40 instructs the display control unit 27 to display a notification that the panning cannot be performed on the monitor 5 while the panning mode is stopped.

  Further, by repeating the setting of the exposure time T1, the brightness per image becomes dark. For this reason, in this embodiment, the brightness of the composite image can be made appropriate by performing brightness correction processing on the composite image in the image processing unit 31.

  The CPU 40 controls each part of the main body of the digital camera 1 according to signals from various processing units such as the release button 2, the operation button 8, and the AE processing unit 29.

  The data bus 41 is connected to various processing units, the frame memory 26, the CPU 40, and the like, and exchanges image data and various instructions.

  Next, processing performed in the present embodiment will be described. FIG. 12 is a flowchart showing processing performed in the present embodiment. Since the present invention is characterized by the shooting process in the panning mode, in the embodiment described below, the process when the panning mode is set will be described.

  The CPU 40 monitors whether or not the release button 2 is half-pressed (step ST1). When the release button 2 is half-pressed, the imaging system 9 performs pre-photographing (step ST2), and the AE processing unit 29 A second AE process is performed using the pre-image acquired by the pre-photographing (step ST3). Then, the CPU 40 performs pre-shooting again with the exposure time T1 set by the second AE process (step ST4), and determines whether or not the pre-image acquired thereby includes a saturated region (step ST5). .

  If step ST5 is affirmed, the CPU 40 determines whether or not an exposure time that is further underexposed can be set from the currently set exposure time T1 (step ST6). Specifically, it is determined whether or not the currently set exposure time T1 is the fastest charge readout time in the imaging device 18. If step ST6 is denied, since it is not possible to perform photographing that is underexposed any more, it is impossible to avoid the presence of saturated regions in a plurality of images acquired in the panning mode. Therefore, the CPU 40 stops the panning mode (step ST7), displays on the monitor 5 that the panning mode is stopped (step ST8), and ends the process.

  On the other hand, if step ST6 is affirmed, the CPU 40 instructs the AE processing unit 29 so that the exposure is under (step ST9). Accordingly, the process returns to step ST4, the AE processing unit 29 performs the second AE process again, and repeats the processes after step ST4. Note that the second AE process again does not include the first AE process.

  If step ST5 is negative, the CPU 40 starts monitoring whether or not the release button 2 has been fully pressed (step ST10), and if step ST10 is affirmative, the CPU 40 performs actual shooting and acquires a plurality of images (step ST10). ST11). Next, the motion analysis unit 36 analyzes the motion of the plurality of images acquired by the actual photographing (step ST12), and the combining unit 37 generates a composite image by superimposing the plurality of images based on the motion analysis result. (Step ST13). Further, the image processing unit 31 performs image processing including brightness correction on the composite image (step ST14). Then, the compression / decompression processing unit 32 generates an image file from the image data of the composite image subjected to the image processing (step ST15), and the media control unit 33 records the image file on the recording medium 34 (step ST16). The process is terminated.

  As described above, according to the present embodiment, since the exposure time T1 is set so that there is no saturated region in each of the plurality of images acquired in the panning mode, there are saturated regions in the plurality of images. As a result, the saturated region and the non-saturated region are not overlapped on the composite image, thereby preventing the saturation region from being multiplexed.

  Here, when the exposure is set so that there is no saturated region, the plurality of images are underexposed and the brightness is insufficient. Therefore, by correcting the brightness of the composite image, it is possible to obtain a composite image having a desired brightness while preventing the saturation region from being multiplexed.

  In addition, in the composite image, the region where the motion is small is in a static state, so that no multiplexing occurs in the composite image even if there is a saturated region. For this reason, it is possible to reduce the amount of calculation for setting the exposure by setting the exposure so that there is no saturated region in a region other than the region where the motion is small in the plurality of images.

  In addition, when the exposure setting value for preventing the saturation area from being present, that is, when the shutter speed reaches the maximum charge readout time and the saturation area cannot be eliminated, the panning mode is stopped and a plurality of images are stopped. By stopping acquisition, it is possible to prevent useless processing by acquiring a plurality of images and generating a composite image in a situation where multiplexing occurs.

  In this case, by displaying on the monitor 5 that the generation of a plurality of images has been stopped, the photographer can know in advance that a composite image will not be generated even if panning is performed. By taking measures such as changing, it is possible to prevent the saturation region from being present in the image.

  In the above embodiment, the brightness of the composite image is corrected. However, the aperture value and the gain of the analog signal are adjusted even when shooting is performed with the exposure time T1 set by the second AE process. Thus, it is possible to prevent the brightness of each of the plurality of images from decreasing. For this reason, when the brightness of each of the plurality of images can be appropriately maintained by adjusting the aperture value and the gain, the image processing unit 31 does not need to perform the brightness correction process on the composite image.

  Further, in the above embodiment, when the underexposure cannot be set, the panning mode is stopped and the process is ended, but the normal shooting mode may be changed.

  The digital camera 1 according to the embodiment of the present invention has been described above. However, the computer functions as a unit corresponding to the AE processing unit 29, the motion analysis unit 36, and the synthesis unit 37, and the process as illustrated in FIG. A program for performing the above is also one embodiment of the present invention. A computer-readable recording medium that records such a program is also one embodiment of the present invention.

The figure which shows the external appearance of the digital camera to which the imaging device by embodiment of this invention is applied (front side) The figure which shows the external appearance of the digital camera to which the imaging device by embodiment of this invention is applied (back side) 1 is a schematic block diagram showing an internal configuration of a digital camera to which a photographing apparatus according to an embodiment of the present invention is applied. Diagram showing an example of division into photometric areas The figure which shows the exposure time by one imaging | photography in normal imaging | photography mode The figure which shows the exposure time by one imaging | photography at the time of panning mode Diagram showing multiple images acquired in panning mode (no saturation area) Diagram showing composite image (no saturation area) Diagram showing multiple images acquired in panning mode (with saturation area) Figure showing a composite image (with saturated area) Diagram for explaining determination of saturation region A flowchart showing processing performed in the present embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 5 Monitor 9 Imaging system 10 Shooting lens 11 Focus lens drive part 23 Light emission control part 24 Flash 28 AF process part 29 AE process part 36 Motion analysis part 37 Synthesis | combination part 40 CPU

Claims (10)

Photographing means for acquiring an image by photographing;
An imaging control means for controlling the imaging means to sequentially acquire a plurality of images sequentially in time;
Motion analysis means for analyzing the motion of the plurality of images;
A combining means for combining the plurality of images to generate a combined image based on the analysis result of the movement;
An exposure processing unit configured to set an exposure of the imaging unit so that a saturated region does not exist in each of the plurality of images at the time of obtaining the plurality of images using the imaging unit. apparatus.   The synthesizing unit detects a moving object from each of the plurality of images based on the analysis result of the motion, and synthesizes the plurality of images so that the positions of the moving objects in each of the plurality of images substantially coincide with each other. 2. The photographing apparatus according to claim 1, wherein the photographing apparatus is a means for generating a composite image.   3. The photographing apparatus according to claim 1, wherein the exposure processing means is means for controlling exposure of the photographing means so that each pixel value of the plurality of images is less than a maximum luminance.   Before the acquisition of the plurality of images, a pre-image for controlling the exposure is acquired, an exposure at the time of acquisition of the plurality of images is set based on the pre-image, and the pre-image is again set by the set exposure. Acquiring, determining whether the saturated region exists in the pre-image, and repeating the setting of exposure and acquiring the pre-image again until the determination is negative. 4. The photographing apparatus according to claim 1, further comprising control means for controlling the processing means.   5. The photographing apparatus according to claim 1, further comprising brightness correction means for correcting the brightness of the composite image.   The exposure processing means is means for setting the exposure of the photographing means so that the saturated region does not exist in a region other than a region where the motion is small in the plurality of images based on the analysis result of the motion. The imaging device according to any one of claims 1 to 5.   The imaging control means is means for stopping the acquisition of the plurality of images when the presence of the saturated region cannot be eliminated even if the exposure set by the exposure processing means reaches a limit value. The imaging device according to any one of 1 to 6.   8. The photographing apparatus according to claim 7, further comprising notification means for notifying that acquisition of the plurality of images has been stopped. Photographing means for acquiring an image by photographing;
Photographing control means for controlling the photographing means to sequentially acquire a plurality of images sequentially in time;
Motion analysis means for analyzing the motion of the plurality of images;
A control method for an imaging apparatus, comprising: combining means for combining the plurality of images to generate a combined image based on the analysis result of the movement,
A method for controlling an imaging apparatus, comprising: setting exposure of the imaging unit so that a saturated region does not exist in each of the plurality of images when acquiring the plurality of images using the imaging unit. Photographing means for acquiring an image by photographing;
Photographing control means for controlling the photographing means to sequentially acquire a plurality of images sequentially in time;
Motion analysis means for analyzing the motion of the plurality of images;
A program for causing a computer to execute a control method of an imaging apparatus including a combining unit that combines the plurality of images and generates a combined image based on the analysis result of the motion,
A program for causing a computer to execute a procedure for setting exposure of the photographing unit so that a saturated region does not exist in each of the plurality of images at the time of obtaining the plurality of images using the photographing unit.

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