JP2010200360A - Imaging apparatus, stroboscopic image generation method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a stroboscopic image at a high speed by extracting an object part of effective frames and synthesizing the extracted object image and a background image. <P>SOLUTION: A one-dimensional data generating section 213 converts images, continuously photographed and stored in an image memory 230 by continuous photographing operation of an imaging section 100 to one-dimensional data whose data amount is small, by projecting them in one direction according to a moving direction of a photographed object. If an object detecting section 214 detects a part which shows the photographed object in respective photographed images, on the basis of the generated one-dimensional data, an image selection section 215 selects images in which the detected photographed object parts do not overlap as effective frames. If the effective frames are selected, on the basis of the one-dimensional data, a background image generation section 216 generates the background image using pixel values of the effective frames, and at the same time, the object detecting section 214 extracts the photographed object part of the respective effective frames. A stroboscopic image generating section 217 synthesizes the extracted photographed object image and the background image to generate a stroboscopic image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device, a strobe image generation method, and a program, and more particularly to an imaging device, a strobe image generation method, and a program suitable for strobe image generation in the imaging device.

  A stroboscopic image (multi-stroboscopic image) is known in which a moving subject is photographed with a fixed camera and a moving image is shown in one image (photo). In the era of film cameras, such strobe images were generated by flashing a moving subject multiple times during a long exposure, but in today's widespread use of digital cameras, images from computers in cameras are used. A strobe image can be generated by the processing.

  In the strobe image generation by such image processing, conventionally, subjects are taken out from images in which subjects do not overlap (for example, Patent Document 1), or a shooting time that seems to be a background is specified from a specific area on a moving image (for example, (Patent Document 2) to determine the position of the subject.

Japanese Patent No. 3793258 Patent No. 35699992

  In such a conventional technique, when the frame rate in continuous shooting or moving image shooting changes or the size of the subject changes, the subject in the image is acquired until the area information about all the captured images can be acquired. The position of cannot be specified. For this reason, when a strobe image is generated from a continuous image or a moving image, it takes time to select an image to be used, and the strobe image cannot be generated at high speed.

  SUMMARY An advantage of some aspects of the invention is that it provides an imaging device, a strobe image generation method, and a program that can generate a strobe image at high speed.

In order to achieve the above object, an imaging apparatus according to the first aspect of the present invention provides:
Imaging means for generating a plurality of continuous captured images by imaging;
One-dimensional data generating means for generating one-dimensional data corresponding to the moving direction of the subject from each captured image generated by the imaging means;
Subject detection means for detecting a portion indicating the subject in each captured image based on the one-dimensional data generated by the one-dimensional data generation means;
Image selecting means for selecting the captured image used for generating the strobe image based on a portion indicating the subject detected by the subject detecting means;
Background image generation means for generating a background image from the captured image selected by the image selection means;
A strobe image generating means for generating a strobe image by combining the background image generated by the background image generating means and the portion indicating the subject in the captured image selected by the image selecting means;
It is characterized by providing.

In the imaging apparatus,
The one-dimensional data generation means includes
It is desirable to generate projection data obtained by projecting each captured image in the direction orthogonal to the moving direction of the subject as the one-dimensional data.

In the imaging apparatus,
The subject detection means preferably detects a portion indicating the subject by comparing a difference between the one-dimensional data and a pixel value at the same coordinate on the one-dimensional data and a threshold value.

In the imaging apparatus,
It is desirable that the image selection unit selects a captured image in which a portion indicating the subject detected by the subject detection unit does not overlap.

In order to achieve the above object, a strobe image generation method according to a second aspect of the present invention includes:
A strobe image generation method for generating a strobe image from imaging by an imaging device,
The imaging device is
A one-dimensional data generation step for generating one-dimensional data according to the moving direction of the subject from a plurality of consecutive captured images generated by imaging;
A subject detection step of detecting a portion indicating the subject in each captured image based on the one-dimensional data generated in the one-dimensional data generation step;
An image selection step of selecting the captured image used for generating the strobe image based on a portion indicating the subject detected in the subject detection step;
A background image generation step of generating a background image from the captured image selected in the image selection step;
A strobe image generation step of generating a strobe image by combining the background image generated in the background image generation step and the portion indicating the subject in the captured image selected in the image selection step;
It is characterized by performing.

In order to achieve the above object, a program according to the third aspect of the present invention is:
On the computer,
A function of generating one-dimensional data corresponding to the moving direction of the subject from a plurality of consecutive captured images generated by imaging;
A function of detecting a portion indicating the subject in each captured image based on the one-dimensional data;
A function of selecting the captured image used for generating a strobe image based on a portion indicating the detected subject;
A function of generating a background image from the selected captured image;
A function of generating a strobe image by combining the generated background image and a portion showing the subject in the selected captured image;
It is characterized by realizing.

  According to the present invention, a strobe image can be generated at a higher speed.

It is a block diagram which shows the structure of the digital camera concerning embodiment of this invention. It is a functional block diagram which shows the function implement | achieved by the control part shown in FIG. It is a flowchart for demonstrating the "strobe image generation process" concerning embodiment of this invention. FIG. 4 is a diagram for explaining a display example of a setting screen displayed in the “strobe image generation processing” shown in FIG. 3, and (a) shows a display example of a setting screen for designating the orientation of the camera; b) shows a display example of a setting screen for designating the moving direction of the subject. It is a figure for demonstrating the captured image concerning embodiment of this invention, (a) illustrated the scene of the continuous shooting required for strobe image generation, (b) was shown to (a). An example of a captured image (continuous shot image) obtained by continuous shooting is shown. FIG. 4 is a flowchart for explaining “one-dimensional data generation processing” executed in “strobe image generation processing” shown in FIG. 3. FIG. 7 is a diagram for explaining the “one-dimensional data generation process” shown in FIG. 6, where (a) shows the relationship between the coordinates in the captured image and the subject movement direction, and (b) and (c) show the captured image. An example of projection and one-dimensional data is shown, and (d) is a diagram in which the one-dimensional data shown in (b) and (c) are superimposed. FIG. 4 is a flowchart for explaining “subject area detection processing” executed in “strobe image generation processing” shown in FIG. 3; FIG. 4 is a flowchart for explaining “subject area detection processing” executed in “strobe image generation processing” shown in FIG. 3; FIG. 4 is a flowchart for explaining “subject area detection processing” executed in “strobe image generation processing” shown in FIG. 3; FIG. 11 is a diagram for explaining the “subject area detection processing” shown in FIGS. 8 to 10, in which (a) shows an example of an object area detected when the moving direction of the object is the X direction; ) Shows an example of a subject area detected when the subject moving direction is the Y direction. 4 is a flowchart for explaining an “effective frame selection process” executed in the “flash image generation process” shown in FIG. 3. 4 is a flowchart for explaining an “effective frame selection process” executed in the “flash image generation process” shown in FIG. 3. It is a figure which shows the example of the selected effective frame. FIG. 4 is a flowchart for explaining “background image generation processing” executed in “strobe image generation processing” shown in FIG. 3; FIG. 4 is a flowchart for explaining “subject image extraction processing” executed in “strobe image generation processing” shown in FIG. 3; It is a figure which shows the example of the produced | generated flash image.

  Embodiments according to the present invention will be described below with reference to the drawings. In the present embodiment, a case where the present invention is realized by a digital still camera (hereinafter referred to as a digital camera) is illustrated. The digital camera 1 according to the present embodiment is assumed to have a function that a general digital still camera has, and at least includes a so-called continuous shooting function. Here, the continuous shooting function is a function capable of obtaining a plurality of continuous captured images by a single shutter operation.

  The digital camera 1 according to the present embodiment has a strobe image generation function that generates a strobe image (multi-strobe image) from a captured image obtained by the continuous shooting function by applying the present invention. Here, the “strobe image” refers to an image in which a moving process of a moving subject is represented in one image. In order to generate a strobe image with the digital camera 1 according to the present embodiment, an object that moves (moves) is imaged by the continuous shooting function. In this case, the digital camera 1 is fixed and imaged.

  FIG. 1 is a block diagram showing a configuration of a digital camera 1 according to an embodiment of the present invention. The schematic configuration of the digital camera 1 according to the present embodiment includes an imaging unit 100, a data processing unit 200, an interface (I / F) unit 300, and the like as illustrated.

  The imaging unit 100 is a part that performs an imaging operation of the digital camera 1, and includes an optical device 110, an image sensor unit 120, and the like as illustrated.

  The optical device 110 includes, for example, a lens, a diaphragm mechanism, a shutter mechanism, and the like, and performs an optical operation related to imaging. In other words, the operation of the optical device 110 collects incident light and adjusts optical elements related to the angle of view, focus, exposure, and the like, such as focal length, aperture, and shutter speed. Note that the shutter mechanism included in the optical device 110 is a so-called mechanical shutter, and when the shutter operation is performed only by the operation of the image sensor, the optical device 110 may not include the shutter mechanism. The optical device 110 operates under the control of the control unit 210 described later.

  The image sensor unit 120 generates an electrical signal corresponding to the incident light collected by the optical device 110, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). (Semiconductor) image sensor. The image sensor unit 120 performs photoelectric conversion to generate an electrical signal corresponding to the received light and output it to the data processing unit 200.

  The data processing unit 200 processes the electrical signal generated by the imaging operation by the imaging unit 100 to generate digital data indicating the captured image, and performs image processing on the captured image. As shown in FIG. 1, the data processing unit 200 includes a control unit 210, an image processing unit 220, an image memory 230, an image output unit 240, a storage unit 250, an external storage unit 260, and the like.

  The control unit 210 includes, for example, a processor such as a CPU (Central Processing Unit), a main storage device (memory) such as a RAM (Random Access Memory), and the like. Each part of the digital camera 1 is controlled by executing the stored program. Further, in the present embodiment, by executing a predetermined program, a function related to each process described later is realized by the control unit 210.

  The image processing unit 220 includes, for example, an ADC (Analog-Digital Converter), a buffer memory, an image processing processor (a so-called image processing engine), and the like. Based on the signal, digital data indicating a captured image is generated.

  That is, when the analog electric signal output from the image sensor unit 120 is converted into a digital signal by the ADC and sequentially stored in the buffer memory, the image processing engine performs so-called development processing on the buffered digital data. Adjust image quality and compress data.

  The image memory 230 includes, for example, a storage device such as a RAM or a flash memory, and temporarily stores captured image data generated by the image processing unit 220, image data processed by the control unit 210, and the like.

  The image output unit 240 includes, for example, an RGB signal generation circuit and the like, converts the image data expanded in the image memory 230 into an RGB signal and the like, and outputs the RGB signal to a display screen (a display unit 310 to be described later).

  The storage unit 250 includes a storage device such as a ROM (Read Only Memory) or a flash memory, and stores programs and data necessary for the operation of the digital camera 1. In the present embodiment, it is assumed that the operation program executed by the control unit 210 and the like, parameters and arithmetic expressions necessary for the processing are stored in the storage unit 250.

  The external storage unit 260 includes a storage device that can be attached to and detached from the digital camera 1 such as a memory card, and stores image data captured by the digital camera 1.

  The interface unit 300 has a configuration related to an interface between the digital camera 1 and its user or an external device. As shown in FIG. 1, the display unit 310, an external interface (I / F) unit 320, an operation unit 330, etc. Consists of

  The display unit 310 includes, for example, a liquid crystal display device, and displays and outputs various screens necessary for operating the digital camera 1, live view images at the time of shooting, captured images, and the like. In the present embodiment, display output of a captured image or the like is performed based on an image signal (RGB signal) from the image output unit 240.

  The external interface unit 320 includes, for example, a USB (Universal Serial Bus) connector, a video output terminal, and the like, and performs output of image data to an external computer device, display output of a captured image to an external monitor device, and the like. .

  The operation unit 330 includes various buttons configured on the outer surface of the digital camera 1, generates an input signal corresponding to an operation by the user of the digital camera 1, and inputs the input signal to the control unit 210. As buttons constituting the operation unit 330, for example, a shutter button for instructing a shutter operation, a mode button for designating an operation mode of the digital camera 1, a cross key and a function button for performing various settings, and the like Is included.

  Here, in the present embodiment, the control unit 210 executes the operation program stored in the storage unit 250 to realize each process described later. In this case, the functions realized by the control unit 210 are implemented. This will be described with reference to FIG.

  FIG. 2 is a functional block diagram illustrating functions realized by the control unit 210. Here, a functional configuration necessary for realizing a function of generating a strobe image from an image captured by the continuous shooting function is shown. In this case, as illustrated, the control unit 210 includes an operation mode processing unit 211, an imaging control unit 212, a one-dimensional data generation unit 213, a subject detection unit 214, an image selection unit 215, a background image generation unit 216, and a strobe image generation. Functions as a unit 217.

  The operation mode processing unit 211 cooperates with the display unit 310 to display screens necessary for the user of the digital camera 1 to specify various operation modes of the digital camera 1 and setting screen displays for each specified operation mode. In addition, the operation mode designated by the user is recognized in cooperation with the operation unit 330, and a program or an arithmetic expression necessary for executing the operation mode is read from the storage unit 250, and the main memory of the control unit 210 is read out. Load to device (memory).

  In this embodiment, it is assumed that the operation mode (strobe image generation mode) related to the strobe image generation function is specified by the user, and each functional configuration of the control unit 210 described below corresponds to the specification of the strobe image generation mode. This is a functional configuration realized by executing a program loaded by the operation mode processing unit 211.

  The imaging control unit 212 executes an imaging operation with the digital camera 1 by controlling the imaging unit 100. Since the strobe image generation function according to the present embodiment generates a strobe image from the captured image obtained by the continuous shooting function of the digital camera 1, the imaging control unit 212 according to the present embodiment has a continuous shooting operation. Control to do. In this case, it is assumed that the imaging operation by the imaging unit 100 is continuously performed while the shutter button of the operation unit 330 is pressed. The captured images (continuous captured images) obtained by the continuous shooting operation controlled by the imaging control unit 212 are sequentially stored in the image memory 230 through the processing by the image processing unit 220. In this case, for example, a frame number is assigned to each of the continuous shot images stored in the image memory 230 in the order of imaging.

  The one-dimensional data generation unit 213 sequentially converts the continuous shot images stored in the image memory 230 into one-dimensional data, and stores it in the main storage device (memory) of the control unit 210, for example. Here, the “one-dimensional data” represents information such as pixel values constituting the image data in one direction component. In the present embodiment, projection data obtained by projecting image data in a predetermined one direction is set as one-dimensional data. In this case, one direction in which the image data is projected is determined based on the moving direction of the target subject (details will be described later).

  The subject detection unit 214 detects a portion (region) indicating the subject in each captured image by comparing one-dimensional data between the captured images. In this case, the subject detection unit 214 detects position information (coordinate information) of the detected subject part. In addition, the subject portion of the image selected by the image selection unit 215 is extracted from the captured image (continuous shot image) stored in the image memory 230.

  The image selection unit 215 selects a captured image in which the subject portions do not overlap based on the position information of the subject portion detected by the subject detection unit 214, and thereby selects an image (frame) suitable for generating a strobe image. Choose from.

  The background image generation unit 216 generates a background image from the captured image selected by the image selection unit 215. Here, for all selected captured images, the pixel values at the same coordinates are acquired, and the background value excluding the subject is generated by using the median value of the pixel values as the pixel value of the coordinates.

  The strobe image generation unit 217 combines the background image generated by the background image generation unit 216 with the image of the subject portion extracted by the subject detection unit 214 from the selected captured image, thereby moving the image into one background image. Strobe images that appear at a plurality of locations without overlapping the subject to be generated are generated.

  The above is the function realized by the control unit 210. In the present embodiment, each function described above is realized by a logical process performed by the control unit 210 executing a program. These functions are, for example, ASIC (Application Specific Integrated Circuit). Or an integrated circuit). In this case, among the functions shown in FIG. 2, the functions related to image processing may be realized by the image processing unit 220.

  The configuration of the digital camera 1 described above is a configuration necessary for realizing the present invention, and a configuration used for a basic function and various additional functions as a digital camera is provided as necessary. .

  The operation of the digital camera 1 having such a configuration will be described below. Here, “strobe image generation processing” executed by the digital camera 1 when the strobe image generation mode is designated will be described with reference to the flowchart shown in FIG. This strobe image generation processing is started when the user of the digital camera 1 operates the operation unit 330 and designates the strobe image generation mode. In this case, the operation mode processing unit 211 loads the program or the like related to the strobe image generation mode from the storage unit 250, so that the following processing is executed by each functional configuration illustrated in FIG.

  When the processing is started, the operation mode processing unit 211 displays a setting screen for setting necessary for implementing the strobe image generation mode on the display unit 310 (step S101). An example of the setting screen displayed here is shown in FIG.

  Here, first, a setting screen for setting the orientation (vertical and horizontal) of the camera as shown in FIG. 4A is displayed. This setting screen is for allowing the user to select whether the digital camera 1 when shooting a continuous shot image as a flash image is in the horizontal position or the vertical position. The user of the digital camera 1 operates the operation unit 330 and designates the direction of the camera during continuous shooting. If the digital camera 1 has, for example, a vertical position detection function using an acceleration sensor or the like, the detection result can be used, and it is not necessary for the user to specify the setting on the setting screen.

  When the orientation of the designated camera is designated, the operation mode processing unit 211 displays on the display unit 310 a setting screen for setting the moving direction of the subject as shown in FIG. That is, in the strobe image generation mode, a moving subject is photographed, and the moving direction is set here. As shown in the figure, for example, an arrow indicating four directions is displayed on the setting screen for setting the moving direction of the subject. Therefore, the user operates the cross key of the operation unit 330 to select the subject to be photographed. Set the direction of movement.

  The operation mode processing unit 211 records the camera direction and the moving direction of the subject set in this way, for example, in the main storage device (memory) of the control unit 210, and thus enters the strobe image generation mode. Setting is performed (step S102).

  Here, FIG. 5A illustrates the relationship between the digital camera 1 and the subject when shooting in the strobe image generation mode. In this case, for example, it is assumed that the subject MV moving from the left to the right is shot with the digital camera 1. In this case, shooting is performed with the direction and angle of view of the digital camera 1 fixed. 5A, the contents set in step S102 are “camera direction: horizontal position” and “subject movement direction: → (right)”. That is, it is set that the subject moves in the horizontal direction.

  As described above, since continuous shooting is performed in the strobe image generation mode, the user of the digital camera 1 starts shooting by operating the shutter button of the operation unit 330 after performing the above settings. . Therefore, the operation mode processing unit 211 instructs the imaging control unit 212 to perform continuous shooting when the strobe image generation mode is designated.

  When the user (photographer) of the digital camera 1 operates (presses) the shutter button (operation unit 330), an input signal corresponding to the operation is input from the operation unit 330 to the control unit 210. As a result, the imaging control unit 212 determines that the shutter button has been operated (step S103: Yes), and controls the imaging unit 100 to perform continuous shooting (step S104). This continuous shooting imaging operation is performed while the user continues to press the shutter button (step S105: No).

  When the shutter operation ends (step S105: Yes), the imaging control unit 212 instructs the imaging unit 100 to end the imaging operation. As a result, the continuous shooting operation is completed, and images (continuous shot images) obtained by the continuous shooting are sequentially stored in the image memory 230 through the processing in the image processing unit 220 (step S106).

  FIG. 5B shows an example of the continuous shot image obtained when the scene illustrated in FIG. As illustrated, the movement of the subject MV is indicated by a plurality of captured images. As described above, since the digital camera 1 is fixed and photographed, the portion other than the subject MV (that is, the background) in each continuous image does not change significantly.

  Here, each of the continuous shot images obtained by one continuous shooting imaging operation is assigned a frame number of 1 to p in the time series of the captured images. In the example of FIG. 5B, images from frame 1 to frame 12 (that is, p = 12) are obtained.

  When continuous shooting is performed in this manner, processing for generating a strobe image using the obtained continuous shot image is sequentially executed. Here, first, the imaging control unit 212 notifies the end of continuous shooting to the one-dimensional data generation unit 213, thereby executing “one-dimensional data generation processing” for converting the continuous shot image into one-dimensional data. (Step S200). This one-dimensional data generation process will be described with reference to the flowchart shown in FIG. In order to facilitate understanding, in the following description, it is assumed that “lateral position” is set as the orientation of the camera.

  When the processing is started, the one-dimensional data generation unit 213 sets the initial value “1” of the frame number to the pointer n for designating the image (frame) to be processed (step S201), and the image memory The image with the frame image number n stored in 230 (the nth image) is selected as a processing target (step S202).

  When the processing target image is selected, the one-dimensional data generation unit 213 initializes the survey coordinates in the image (step S203). Here, the coordinates in which each of the x coordinate and the y coordinate is “0” are set as initial investigation coordinates. Here, the coordinates on the image will be described with reference to FIG. In this embodiment, since the orientation of the camera is “horizontal position”, the captured image obtained by such a digital camera 1 is a horizontally long image as shown in FIG. In this case, the horizontal direction of the image is “X direction”, and the vertical direction is “Y direction”. Here, the upper left corner of such an image is taken as the coordinate origin (0, 0). In this case, if the number of pixels in the X direction is sizeX, the maximum value of the x coordinate is sizeX-1. Similarly, if the number of pixels in the Y direction is sizeY, the maximum value of the y coordinate is sizeY-1.

  Next, the one-dimensional data generation unit 213 determines that the subject movement direction set in step S102 of the strobe image generation process (FIG. 3) is the X direction in the coordinate system of the captured image defined as shown in FIG. Or Y direction (step S204). Here, when the camera is in the horizontal position, if any of the left and right directions is specified on the setting screen shown in FIG. 4B, the moving direction of the subject is the X direction (horizontal direction). On the other hand, if any one of the up and down directions is designated, the moving direction of the subject is the Y direction (vertical direction).

  In the scene illustrated in FIG. 5A, since the subject MV moving in the lateral direction is captured, it is determined that the moving direction of the subject is the X direction (step S204: Yes). When the moving direction of the subject is the X direction, the one-dimensional data generation unit 213 performs a process of projecting an image in a direction orthogonal to the moving direction of the subject, that is, the Y direction.

  In this case, the one-dimensional data generation unit 213 projects in the Y direction by adding the pixel values in the Y direction in all the coordinates in the X direction of the processing target image (step S205, step S206, step S207: Yes). Here, since the survey coordinates are initialized in step S203, first, the pixel values of the y coordinate corresponding to the x coordinate 0 are added together, and the result is stored in the main storage device (memory) of the control unit 210. . Next, the value of the x coordinate is incremented by 1, and the same calculation is performed for the next x coordinate. Such processing is repeated for the x-coordinate size of the image in the X direction, that is, the number of pixels in the X direction.

  On the other hand, when the moving direction of the subject is the Y direction (up and down direction) (step S204: No), the image is projected in the direction orthogonal to the moving direction, that is, the X direction by the same method (step S208). , Step S209, Step S210: Yes).

  When the projection on the processed image ends (step S207: No or step S210: No), the one-dimensional data generation unit 213 increments the pointer n by 1 (step S211), and the frame number corresponding to the new pointer n is consecutive. If it is equal to or less than the frame number assigned by the shooting (step S212: No), the next continuous shot image is selected as a processing target (step S202).

  On the other hand, when the projection for all the continuous shot images is completed (step S212: Yes), the process returns to the flow of the strobe image generation process (FIG. 3).

  By such projection by the one-dimensional data generation process, each of the continuous shot images is converted into one-dimensional data as shown in, for example, FIGS. 7B and 7C. Such one-dimensional data generation can be expressed by, for example, Equation 1.

  When the one-dimensional data (projection data) is generated for each of the continuous shot images in this way, the one-dimensional data generation unit 213 associates the generated one-dimensional data with the frame number of the original captured image. Are sequentially stored in the image memory 230, and the subject detection unit 214 is notified that one-dimensional data for all the continuous shot images has been generated. In response to the notification from the one-dimensional data generation unit 213, the subject detection unit 214 executes “subject region detection processing” for detecting a subject portion using the converted one-dimensional data (step S300).

  Here, the concept of the process of detecting the subject portion from the one-dimensional data of the continuous shot image will be described with reference to FIGS. 7B to 7D. FIG. 7B shows an example (upper row) of a captured image when an image is taken without the subject MV in the scene shown in FIG. 5A and an example (lower row) of one-dimensional data of the captured image. FIG. 7C shows an example of a captured image in the state where the subject MV is present (upper stage) and an example of one-dimensional data (lower stage) of the captured image.

  As described above, when the strobe image is generated by the digital camera 1 according to the present embodiment, the digital camera 1 is fixed and continuous shooting is performed. Therefore, there is no significant change in the background portion other than the subject MV between the plurality of continuous shot images obtained. Therefore, when one-dimensional data between continuous shot images is compared, a change appears in the range of the subject MV. Here, for easy understanding, one-dimensional data of an image in which the subject MV is not shown and an image in which the subject MV is shown are shown in FIGS. 7B and 7C, respectively. Comparing the respective one-dimensional data, the data of the part where the subject MV is shown in FIG. 7C is different from FIG. 7B, and the other parts are the same data.

  That is, when the one-dimensional data of both images are overlapped as shown in FIG. Such a place where the one-dimensional data does not match is a range where the subject MV is captured (a range in the X direction if the movement direction of the subject is the X direction, a range in the Y direction if the movement direction is the Y direction). . Therefore, if the difference of the one-dimensional data between the continuous image which adjoins in time series order is taken, the transition of a to-be-photographed range will be shown.

  The subject detection unit 214 detects a subject portion in the continuous shot image by performing processing based on such a principle. The subject area detection process (step S300) executed here will be described with reference to the flowcharts shown in FIGS.

  When the process is started, the subject detection unit 214 first determines whether the moving direction of the subject is the X direction or the Y direction based on the setting content in step S102 of the strobe image generation process (FIG. 3) (step S102). S301). Hereinafter, the case where the moving direction of the subject is the X direction (step S301: Yes) will be mainly described.

  In this case, the subject detection unit 214 initializes coordinates in the X direction to be investigated. As described above, since the coordinate range of the captured image is (0,0) to (sizeX-1, sizeY-1), the initial value of the x coordinate is set to “0” (step S302).

  Next, the subject detection unit 214 sequentially designates frames of the continuous shot image by designating the pointer n to be 1 to p, and each frame is generated by the “one-dimensional data generation process” (FIG. 6). One-dimensional data corresponding to the coordinate x is acquired from the image memory 230 and stored in, for example, the main storage device (memory) of the control unit 210 (step S303 to step S306: No).

  When the one-dimensional data of all the frames is acquired (step S306: Yes), the subject detection unit 214 sorts the acquired one-dimensional data (step S307), and the coordinate x indicates the background image. In this case, the pixel value fb (x) is set (step S308).

  Such an operation is performed at each point of the x coordinate (Step S309, Step S310: No). When background pixel values fb (x) for all x coordinates (0 to sizeX-1) in all frames are obtained (step S310: Yes), the process proceeds to step S311 (FIG. 9).

  Here, the subject detection unit 214 sets the pointer n to the frame initial value “1” and the x coordinate to the coordinate initial value “0” (steps S311 and S312). Then, the subject detection unit 214 calculates the difference fd (x) (= |) between the pixel value fn (x) at the x coordinate of the nth frame and the background pixel value fb (x) at the coordinate x obtained in step S308. fb (x) −fn (x) |) is calculated (step S313: Yes, step S314).

  The subject detection unit 214 determines whether the calculated difference fd (x) is larger than a predetermined threshold DiffTh, thereby determining whether the coordinate x is a portion indicating the subject (step S315). ). That is, since the background pixel value fb (x) is a pixel value when the coordinate x indicates the background image, if the actual pixel value fn (x) is significantly different from the pixel value of the background image, the frame The coordinate x at n indicates other than the background, that is, the subject MV. Therefore, if the threshold value DiffTh for performing such determination is set and the difference fd (x) is larger than the threshold value DiffTh, it is possible to determine that the pixel value fn (x) is a pixel value indicating the subject portion.

  Here, when the pixel value fn (x) is equal to or less than the threshold value DiffTh (step S315: No), the coordinate x in the nth frame is not the subject portion, so the x coordinate is incremented by 1 (step S316), and the image size is within the image size. (Step S313: Yes), the same determination is performed for the next coordinate x (steps S314 and S315).

  Here, since the x coordinate is set to “0”, which is the left end of the image, in the initialization in step S312, when it is determined that the coordinate x of the survey coordinate indicates the pixel of the subject portion (step S315: Yes). The subject detection unit 214 sets the x coordinate as the coordinate L (n) corresponding to the left end of the subject portion in the nth frame (step S317).

  In other words, since the determination is performed from the position of x = 0, which is the left end of the captured image, while the x coordinate is incremented by 1, the processing of step S312 to step S316 has searched the subject portion from the left end of the image. become. Here, since the subject range with respect to the x-coordinate has a width, it is necessary to specify the right end of the subject range. Therefore, when the left end of the subject portion is specified, the subject detection unit 214 performs an operation of searching for the right end of the subject portion.

  In this case, the search for the subject portion is started from the right end side of the captured image. Therefore, the subject detection unit 214 sets the survey coordinate x to sizeX-1 that is the x coordinate indicating the right end of the captured image (step S318). Here, since the right end of the subject portion is searched, the survey coordinate x must be on the right side of the coordinate L (n) that is the left end of the subject portion in step S317. Therefore, if the survey coordinate x is larger than L (n) (step S319: Yes), the subject detection unit 214 calculates fd (x) for the coordinate x (step S320), and the calculated fd (x) is calculated. It is determined whether or not the threshold value is greater than DiffTh (step S321).

  If fd (x) at the coordinate x is equal to or less than the threshold DiffTh and does not indicate the subject portion (step S321: No), the subject detection unit 214 shifts the survey coordinate x by -1 to the left by one coordinate. (Step S322), the same determination is made for the coordinate x (step S319, step S320, step S321). In this way, when searching from the right end side of the captured image and determining that the pixel at the survey coordinate x indicates the subject portion (step S321: Yes), the subject detection unit 214 detects the coordinate x in the frame n. Is the coordinate R (n) of the right end of the subject portion at (step S323).

  Note that when the subject portion is not detected even after searching from the left end of the image (step S313: No), or when the x coordinate set from the right end side is on the left side of the subject left end L (n) (step S319: No). It is assumed that there is no subject portion in the frame n. For example, a numerical value is set such that L (n) = R (n), and the investigation target is moved to the next frame (step S324).

  Also, when the subject range is detected for the frame n, the above-described processing is performed with the next frame as an investigation target (step S324, step S325: No). When the subject area is detected for all the frames (step S3325: Yes), the flow returns to the strobe image generation process (FIG. 3).

  The above is the operation for detecting the subject area when the moving direction of the subject is the X direction. In this case, as shown in FIG. 11A, the range in the X direction of the subject MV appearing in each frame is sequentially obtained. The coordinates (L (n) and R (n)) of the subject range obtained in this way are stored in a main memory (memory) or the like in association with the frame number.

  On the other hand, when the moving direction of the subject is the Y direction, the same process as described above is performed in the Y direction. That is, by performing steps S326 to S334 in FIG. 8 and steps S335 to S349 in FIG. 10, the upper end coordinates T (n) and the lower end coordinates B (n) of the subject image appearing in each frame are obtained. (Refer FIG.11 (b)).

  When the subject area is detected in this way, the subject detection unit 214 notifies the image selection unit 215 to that effect. In this case, the image selection unit 215 executes “effective frame selection processing” (step S400 in FIG. 3) for selecting a captured image (effective frame) used for generating a strobe image based on the detected subject area. To do. This effective frame selection process will be described with reference to the flowcharts shown in FIGS.

  When the process is started, the image selection unit 215 first determines whether the moving direction of the subject is the X direction or the Y direction (step S401). Here, the flowchart of FIG. 12 shows processing when the moving direction of the subject is the X direction, and the flowchart of FIG. 13 shows processing when the moving direction is the Y direction.

  When the moving direction of the subject is the X direction (step S401: Yes), the image selecting unit 215 sets the pointer n to the frame initial value “1” and based on the detection result in the subject region detection process described above, It is determined whether or not there is a subject area in the frame (steps S402 to S403). Here, L (n) and R (n) (or T (n) and B (n)) indicating the range of the subject area are recorded for frame n, and L (n) ≠ R (n) If (or T (n) ≠ B (n)), it is determined that the subject area is detected from frame n.

  If no subject area is detected from frame n (step S403: No), the nth frame is an invalid frame that is not used to generate a strobe image (step S404), and the subject area is set for the next frame. Is determined (step S409, step S410: No, step S403).

  In this manner, the presence / absence of the subject region is sequentially determined from the first frame of the continuous shot image. Then, the image selection unit 215 selects the first frame determined to have a subject area as an effective frame (step S403: Yes, step S405: No, step S407). Here, the image selection unit 215 assigns an effective frame number different from the frame number to the frame (continuous shot image) selected as the effective frame. In this case, “1” is assigned as the effective frame number to the frame selected as the first effective frame in step S407. Further, the image selection unit 215 sets the frame number of the frame selected in step S407 to the pointer m for designating an effective frame (step S408).

  When the first valid frame is selected and the frame number of this frame is set to the pointer m, the image selection unit 215 increments the pointer n by 1 and determines whether or not there is a subject area for the next frame (steps S409 and S410). : No, step S403). That is, the next frame used for generating the strobe image is searched. Here, after the first valid frame is selected (step S405: Yes), the subject area between the investigation target frame (nth frame) and the last valid frame (frame designated by the pointer m) is selected. By comparing these positions, a frame in which the previous effective frame and the subject portion do not overlap is selected as an effective frame.

  Here, when the moving direction of the subject is the X direction, there are two types of movement: left-to-right movement and right-to-left movement. If moving from left to right, the subject area in frame n needs to be on the right side of the subject area in frame m. On the other hand, if moving from right to left, the subject area in frame n needs to be on the left side of the subject area in frame m.

  Therefore, the image selection unit 215 determines that the subject left end L (n) in the frame n is larger than the subject right end R (m) of the frame m, or the subject right end R (n) in the frame n is the subject left end L (of the frame m. If smaller than m), it is determined that the subject portion of frame n does not overlap the subject portion of frame m (step S406).

  If the subject area of the frame n matches such a condition (step S406: Yes), the image selection unit 215 selects the nth frame as an effective frame (step S407). On the other hand, if the condition is not met (step S406: No), the n-th frame is set as an invalid frame that is not used for generating the strobe image (step S404).

  As for the subsequent continuous shot images, when effective frames are selected by such condition determination and all continuous shot images are examined and effective frames are selected (step S410: Yes), as shown in FIG. The effective frame to which the effective frame number different from the frame number is assigned and the invalid frame not used for generating the strobe image are distinguished.

  It is assumed that the effective frame numbers are serial numbers in the time series in the selected effective frame as shown in the figure. In this case, the number of selected effective frames is p ′ (p ′ ≦ p). As described above, by adding the identification information indicating the selected effective frame, the effective frame can be distinguished from the continuous shot images stored in the image memory 230. However, by deleting the invalid frame from the image memory 230, the effective frame can be distinguished. Only the frame may be left in the image memory 230.

  The above is the operation of selecting an effective frame when the subject has moved in the X direction. Even when the moving direction of the subject is the Y direction (step S401: No in FIG. 12), an effective frame can be selected by the same process. That is, by performing steps S411 to S419 in the flowchart shown in FIG. 13, a frame in which the images of the subject moving in the Y direction do not overlap is selected as the effective frame, but the selection after the first effective frame is selected. The condition considers the case where the subject moves from top to bottom and the case where the subject moves from bottom to top.

  That is, if moving from the top to the bottom, the subject area in the frame n needs to be below the subject area in the effective frame m selected immediately before. On the other hand, if it has moved from the bottom to the top, the subject area in the frame n needs to be above the subject area in the effective frame m selected immediately before.

  Therefore, the image selection unit 215 determines that the subject upper end T (n) in the frame n is larger than the subject lower end B (m) of the effective frame m selected immediately before, or the subject lower end B (n) in the frame n is immediately before If it is smaller than the subject upper end T (m) of the selected effective frame m, it is determined that the subject portion of the frame n does not overlap with the subject portion of the effective frame m selected immediately before (step S415 in FIG. 13).

  As described above, the subject area is detected from the one-dimensional data obtained by projecting the captured image in one direction, and the frame in which the subject portions do not overlap is selected. That is, by selecting an image (effective frame) used for generating a strobe image based on one-dimensional data with a small amount of data, the amount of processing until image selection is performed rather than using all data of the captured image. Is greatly reduced.

  When an image (effective frame) used for generating a strobe image is selected in this way, in the strobe image generation process (FIG. 3), a background image of the strobe image is generated using the image data of the selected frame. “Background image generation processing” (step S500) for the purpose, and “Subject image extraction processing” (step S600) for extracting the image of the subject portion from the effective frame are sequentially executed.

  The “background image generation process” will be described with reference to the flowchart shown in FIG. This background image generation processing is started when the image selection unit 215 notifies the background image generation unit 216 that the effective frame selection processing has ended.

  When the process is started, the background image generation unit 216 initializes coordinates (x, y) to be examined on the effective frame. Here, by setting the initial value “0” of each of x and y, the coordinate origin (0, 0) of the effective frame is set as the survey coordinates (step S501).

  Next, the background image generation unit 216 stores the pixel value of the set coordinates (x, y) in the image memory 230 by sequentially specifying 1 to p ′ with the pointer n ′ that specifies the effective frame. It acquires sequentially from all the effective frames (1-p ') (step S502-step S504, step S505: No).

  When the pixel values of the coordinates (x, y) are acquired from all the effective frames (step S505: Yes), the background image generation unit 216 sorts the acquired pixel values (step S506) and sets the median value to the coordinates (x , Y) is a pixel value (background pixel value fb ′ (x, y)) when the background portion is indicated (step S507).

  When the background pixel value fb ′ (x, y) for the coordinates (x, y) is obtained, the background image generation unit 216 sequentially sets the coordinates in the coordinate range of the effective frame as the investigation coordinates, and the coordinates (x, y). A background pixel value fb ′ (x, y) is obtained for (Step S508, Step S509: No, Step S502 to Step S507). Here, for example, by sequentially incrementing the x-coordinate with respect to the same y-coordinate by +1, when the x-coordinate reaches the right end of the image, the y-coordinate is incremented by 1 and the coordinate x is set to 0 (0) , 0) to (sizeX−1, sizeY−1) are sequentially obtained to obtain a background pixel value fb ′ (x, y) at each coordinate.

  By using the background pixel value fb ′ (x, y) obtained from all coordinates as the pixel value at each coordinate, a background image showing only the background portion shown in the effective frame can be obtained. When the background image generation unit 216 generates the background image in this way (step S510), the background image generation unit 216 stores the generated background image in the image memory 230 and notifies the subject detection unit 214 that the background image has been generated. Exit.

  In this case, returning to the flow of the strobe image generation process (FIG. 3), the “subject image extraction process” (step S600) is executed. This subject image extraction process is executed by the subject detection unit 214 when the background image is generated. This subject image extraction processing will be described with reference to the flowchart shown in FIG.

  When the process is started, the subject detection unit 214 initializes the coordinates (x, y) (step S601) and the target frame (step S602), and coordinates from each of the effective frames 1 to p ′. The pixel value fn ′ (x, y) of (x, y) is sequentially acquired, and the difference fd ′ (x, y) from the background pixel value fb ′ (x, y) at the coordinate (x, y) is calculated. (Step S603 to Step S605, Step S606: No).

  When the difference fd ′ (x, y) at the coordinates (x, y) is calculated from all the effective frames (step S606: Yes), the subject detection unit 214 calculates the standard deviation fs of the calculated difference fd ′ (x, y). (x, y) is calculated (step S607). Here, for example, the subject detection unit 214 calculates Formula 2 to calculate the standard deviation fs (x, y).

  When the standard deviation fs (x, y) at the coordinates (x, y) is calculated, the subject detection unit 214 moves the survey coordinates within the coordinate range of the effective frame, and the standard deviation fs (x, y) at each coordinate. Are sequentially calculated (step S608, step S609: No, step S602 to step S607).

  When the standard deviation fs (x, y) at each coordinate is calculated, the subject detection unit 214 sets the variation threshold move used for determining the subject part in each effective frame based on the calculated standard deviation fs (x, y). (Step S610). Here, for example, the variation threshold value move is set by calculating Equation 3.

  When the variation threshold move is set, the subject detection unit 214 calculates a pixel value satisfying the difference fd ′ (x, y) ≧ the variation threshold move from each of the effective frames (1 to p ′) stored in the image memory 230. Obtain (Step S611, Step S612, Step S615, Step S616: No).

  The subject detection unit 214 sets the pixel value satisfying such a condition as a pixel value indicating the subject portion in the frame n ′ (step S614). In this case, for example, the difference fd ′ (x, y) ≧ the variation threshold value. Data for which the coordinate for move is “1” and the coordinate for difference fd ′ (x, y) <variation threshold move is “0” is generated. For example, the generated data of 0 and 1 are continuous. Label areas with the same number and separate areas with different numbers. Then, the pixel value for the coordinate that becomes only the maximum region among the labeled regions is set as the pixel value indicating the subject portion in the frame n ′.

  At this time, the subject detection unit 214 performs, for example, processing for complementing defects such as expansion, hole filling, and contraction, and processing for adding a transmission parameter to the periphery of the subject region (step S613).

  Through the processing as described above, an image (subject image) indicating the subject portion is extracted from each effective frame. When the subject image is extracted from the effective frame, this process is terminated, and the flow returns to the strobe image generation process (FIG. 3). At this time, the background image generation unit 216 notifies the strobe image generation unit 217 that the subject image has been extracted.

  In the strobe image generation process flow, the strobe image generation unit 217 combines the background image generated in the background image generation process (step S500) and the subject image in each effective frame extracted in the subject image extraction process. Thus, a strobe image as shown in FIG. 17 is generated (step S107).

  The generated strobe image is displayed on the display unit 310 through the image output unit 240 and is also stored in the storage unit 250 or the external storage unit 260 in response to an instruction input by the user of the digital camera 1 operating the operation unit 330. Then (step S108), the process ends.

  When the camera is in the vertical position, a strobe image can be generated in the same manner by performing the above-described processing in the coordinate system when the captured image is rotated by −90 ° or 90 °.

  As described above, a strobe image can be generated at high speed by applying the present invention as in the above embodiment.

  In other words, an image obtained by continuous shooting is converted into one-dimensional data with a small amount of data, and a frame necessary for generating a strobe image is selected based on the one-dimensional data, thereby reducing the processing amount until image selection. This greatly reduces the processing time.

  In this case, the one-dimensional data can be projection data obtained by projecting a captured image in one direction. Therefore, one-dimensional data can be generated by a simple process.

  When such projection data is generated, one-dimensional data regarding the moving direction can be obtained by projecting in one direction orthogonal to the moving direction of the subject. With such projection data, it is possible to easily determine the overlap of the subject portions in the movement direction. Therefore, only by designating the moving direction of the subject, it is possible to automatically generate a combined strobe image without overlapping the subjects.

  Since the processing amount for generating one-dimensional data and selecting an effective frame is small, it is possible to generate a strobe image at high speed without providing a processor or the like of the digital camera with more processing power than necessary. As a result, for example, even with a compact digital camera, a strobe image can be generated without stress on the spot.

  For example, when checking a form related to an action such as a sport with a strobe image, there is no need to prepare a large-scale device such as a personal computer. Can be done in a short time.

  In addition, since effective frames can be selected at high speed, a strobe image can be generated at high speed even if there are many continuous shot images. In other words, when creating a strobe image, there is no need to limit the number of captured images and the continuous shooting speed, so it is possible to generate a strobe image even when shooting regardless of the continuous shooting speed or shooting start timing. it can.

  The said embodiment is an example and the application range of this invention is not restricted to this. That is, various applications are possible, and all embodiments are included in the scope of the present invention.

  For example, in the above embodiment, the search for the subject area and the acquisition of the background pixel value are performed by shifting the coordinates one by one. However, for example, the processing can be performed at a higher speed by moving the coordinates intermittently.

  In the above embodiment, the background pixel value is the median value of all the pixel values, but is not limited thereto, and may be an average value, for example.

  Further, the processing speed may be increased by performing processing after making the number of coordinates of the target image smaller than the actual image size.

  In the above embodiment, the background image is generated with the pixel value based on the difference of the pixel value at each coordinate. However, if the subject region is not detected in the continuous shot image, the above-described background image generation processing is not performed. In addition, the image may be adopted as the background image.

  In the above embodiment, a strobe image in which subject images do not overlap is generated by selecting a frame in which subject portions do not overlap as effective frames. However, the present invention is not limited to this. A strobe image showing the subject portion may be generated. In this case, for example, an interval (for example, the number of pixels) of the subject image desired by the user is specified on the setting screen before shooting. When detecting the subject area from the one-dimensional data, L (n) (or R (n)) or T (n) (or B (n) of the subject area detected in the first selected effective frame ), The frame whose position separated by the specified interval is L (n) (or R (n)) or T (n) (or B (n)) is sequentially selected as the next and subsequent valid frames. Thus, it is possible to generate a strobe image in which the subject portion appears at a specified interval. In this case, the subject portion does not overlap if the specified interval is large, but the subject portion overlaps if the interval is small. Also in this case, since the subject area is detected from the one-dimensional data, a strobe image can be generated at high speed.

  In the case where the present invention is realized by an imaging apparatus such as the digital camera 1 exemplified in the above embodiment, each function of the control unit 210 can be provided in addition to the provision of the configuration and functions according to the present invention in advance. By applying a program that realizes the same function as the above, it is possible to make an existing imaging device function as the imaging device according to the present invention.

  In the above-described embodiment, a digital still camera is shown as an example of an imaging device. However, the imaging device can be of any form, and can be realized with a single digital still camera. The present invention may be applied to various electronic devices (for example, cellular phones) provided.

  In the above embodiment, an example in which a strobe image is generated from an image obtained by a continuous shooting function by a still camera has been shown. However, since it is sufficient that a frame image in which a subject is continuously changed is obtained, it can be obtained from moving image data. A strobe image can be generated. Therefore, even if the present invention is applied to a video camera or various imaging devices having a moving image imaging function, a strobe image can be generated at high speed.

  Even in such a case, by applying the program, an existing apparatus can be caused to function as the imaging apparatus according to the present invention.

  The application method of such a program is arbitrary. For example, the program can be applied by being stored in a storage medium such as a CD-ROM or a memory card, or can be applied via a communication medium such as the Internet.

  If the apparatus can perform image processing, high-speed strobe image generation can be realized by applying the above program. In other words, the present invention is not limited to an imaging apparatus, and for example, by applying the above program to a personal computer or the like, a strobe image can be generated at high speed from an image captured in advance.

DESCRIPTION OF SYMBOLS 1 ... Digital camera, 100 ... Imaging part, 110 ... Optical apparatus, 120 ... Image sensor part, 200 ... Data processing part, 210 ... Control part, 211 ... Operation mode processing part, 212 ... Imaging control part, 213 ... One-dimensional data Generation unit, 214 ... Subject detection unit, 215 ... Image selection unit, 216 ... Background image generation unit, 217 ... Strobe image generation unit, 220 ... Image processing unit, 230 ... Image memory, 240 ... Image output unit, 250 ... Storage unit , 260 ... external storage unit, 300 ... interface unit, 310 ... display unit, 320 ... external interface unit, 330 ... operation unit

Claims (6)

Imaging means for generating a plurality of continuous captured images by imaging;
One-dimensional data generating means for generating one-dimensional data corresponding to the moving direction of the subject from each captured image generated by the imaging means;
Subject detection means for detecting a portion indicating the subject in each captured image based on the one-dimensional data generated by the one-dimensional data generation means;
Image selecting means for selecting the captured image used for generating the strobe image based on a portion indicating the subject detected by the subject detecting means;
Background image generation means for generating a background image from the captured image selected by the image selection means;
A strobe image generating means for generating a strobe image by combining the background image generated by the background image generating means and the portion indicating the subject in the captured image selected by the image selecting means;
An imaging apparatus comprising: The one-dimensional data generation means includes
Generating, as the one-dimensional data, projection data obtained by projecting each captured image in a direction orthogonal to the moving direction of the subject;
The imaging apparatus according to claim 1. The subject detection means detects a portion indicating the subject by comparing a difference between the one-dimensional data and a pixel value at the same coordinate on the one-dimensional data and a threshold value;
The imaging apparatus according to claim 1 or 2, wherein The image selection means includes
Selecting a captured image in which the portion indicating the subject detected by the subject detection means does not overlap;
The image pickup apparatus according to claim 1, wherein the image pickup apparatus is an image pickup apparatus. A strobe image generation method for generating a strobe image from imaging by an imaging device,
The imaging device is
A one-dimensional data generation step for generating one-dimensional data according to the moving direction of the subject from a plurality of consecutive captured images generated by imaging;
A subject detection step of detecting a portion indicating the subject in each captured image based on the one-dimensional data generated in the one-dimensional data generation step;
An image selection step of selecting the captured image used for generating the strobe image based on a portion indicating the subject detected in the subject detection step;
A background image generation step of generating a background image from the captured image selected in the image selection step;
A strobe image generation step of generating a strobe image by combining the background image generated in the background image generation step and the portion indicating the subject in the captured image selected in the image selection step;
A strobe image generation method comprising: On the computer,
A function of generating one-dimensional data corresponding to the moving direction of the subject from a plurality of consecutive captured images generated by imaging;
A function of detecting a portion indicating the subject in each captured image based on the one-dimensional data;
A function of selecting the captured image used for generating a strobe image based on a portion indicating the detected subject;
A function of generating a background image from the selected captured image;
A function of generating a strobe image by combining the generated background image and a portion showing the subject in the selected captured image;
A program characterized by realizing.

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