JP5736796B2 - Electronic camera, program and recording medium - Google Patents

Description

  The present invention relates to an electronic camera, a program, and a recording medium on which the program is recorded.

  2. Description of the Related Art Conventionally, an electronic camera that automatically takes a panning shot while reducing blurring of a main subject has been proposed (see, for example, Patent Document 1).

JP 2009-130557 A

  However, in the above-described shooting by the electronic camera, the moving direction of the main subject is limited to, for example, the horizontal direction in the shooting screen. For this reason, depending on the moving direction of the main subject, it may be difficult to perform shooting that reduces the blur of the main subject.

  In view of the above circumstances, an object of the present invention is to provide a photographing unit that reduces blurring of a main subject even when the main subject moves in any direction on the photographing screen.

An electronic camera according to an aspect of the present invention includes an imaging unit that captures a subject image and outputs image data, a main subject region detection unit that detects a main subject region where a main subject exists using the image data, and the main A movement for detecting movements of the plurality of detection areas set in the main subject area using a setting unit that sets a plurality of detection areas in the subject area and a plurality of the image data captured at different times A detection unit; and a control unit that controls the imaging unit to output recording image data when the motion of the plurality of detection areas detected by the motion detection unit is smaller than a predetermined threshold. Features.

The program according to an aspect of the present invention includes an imaging process that captures a subject image and outputs image data, a main subject area detection process that detects a main subject area where a main subject exists using the image data, and the main subject Motion detection for detecting movement of the plurality of detection areas set in the main subject area using setting processing for setting a plurality of detection areas in the area and a plurality of the image data captured at different times And a control process for performing control to output the recording image data by performing the imaging process when the motions of the plurality of detection areas detected by the motion detection process are smaller than a predetermined threshold. To be executed.

The recording medium of one embodiment of the present invention includes an imaging process that captures a subject image and outputs image data, a main subject area detection process that detects a main subject area where a main subject exists using the image data, and the main subject area detection process. A setting process for setting a plurality of detection areas in a subject area and a motion for detecting movements of the plurality of detection areas set in the main subject area using a plurality of the image data captured at different times A detection process and a control process for performing control to output the image data for recording by performing the imaging process when the motions of the plurality of detection areas detected by the motion detection process are smaller than a predetermined threshold value. Instructions to be executed are recorded.

  The present invention can provide imaging means for reducing the shake of the main subject even when the main subject moves in any direction on the imaging screen.

The block diagram which shows the structural example of the electronic camera 1 The figure explaining an example of the setting process of an observation area | region The figure explaining an example of the detection process of the motion amount for every observation area The figure explaining another example of the detection processing of the motion amount for every observation area A flowchart showing an example of the operation of the electronic camera 1 Sequence diagram showing an example of shooting operation in blur suppression mode The figure which shows an example of the criterion of the movement state of the main subject The figure explaining an example of the photography scene where a main subject moves to an optical axis direction The figure explaining an example of automatic zoom mode The figure explaining another example of automatic zoom mode

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of the electronic camera 1. Here, the electronic camera 1 has a “blur suppression mode” in which shooting is performed with blurring of the subject suppressed. The shake suppression mode is a shooting mode in which shooting is automatically performed when, for example, a moving main subject stops on the shooting screen.

  The electronic camera 1 includes a photographing optical system 10, a lens driving unit 11, a diaphragm 12, a diaphragm driving unit 13, an image sensor 14, a signal processing unit 15, a RAM (Random Access Memory) 16, and an image processing unit. 17, flash memory 18, recording interface unit (hereinafter referred to as “recording I / F unit”) 19, display interface unit (hereinafter referred to as “display I / F unit”) 20, display monitor 21, and touch panel 22. , An operation unit 23, a release button 24, a CPU (Central Processing Unit) 25, and a data bus 26.

  Among these, the signal processing unit 15, the RAM 16, the image processing unit 17, the flash memory 18, the recording I / F unit 19, the display I / F unit 20, and the CPU 25 are connected to each other via a data bus 26. The lens driving unit 11, the aperture driving unit 13, the signal processing unit 15, the touch panel 22, the operation unit 23, and the release button 24 are connected to the CPU 25.

  The photographic optical system 10 includes a plurality of lens groups including a zoom lens that adjusts the focal length and a focus lens that adjusts the imaging position on the imaging surface of the imaging element 14. The lens driving unit 11 adjusts the lens positions of the zoom lens and the focus lens in the photographic optical system 10 in the direction of the optical axis (L in the figure) according to an instruction from the CPU 25. For the sake of simplicity, FIG. 1 shows the photographing optical system 10 as a single lens.

  The diaphragm 12 adjusts the amount of light per unit time incident on the image sensor 14. The diaphragm drive unit 13 adjusts the opening amount of the diaphragm 12 in accordance with an instruction from the CPU 25.

  The image sensor 14 captures a subject image that has passed through the photographing optical system 10 and the diaphragm 12 and acquires an analog image signal. The analog image signal output from the image sensor 14 is input to the signal processing unit 15. Note that three types of color filters of R (red), G (green), and B (blue) are arranged on the imaging surface of the imaging device 14 in, for example, a Bayer array. Further, the charge accumulation time of the image sensor 14 and the reading of the image signal are controlled by a timing generator (not shown).

  Here, the image sensor 14 captures an image for recording (main image) in response to a full press operation of a release button 24 described later. The imaging element 14 continuously captures images for observation (through images) at predetermined intervals during standby for shooting. In addition, the imaging element 14 captures a recording image in response to an instruction from an acquisition unit 25e described later in the shake suppression mode.

  The imaging device 14 is a CCD (Charge Coupled Device) type or CMOS (Complementary Metal-Oxide Semiconductor) type color image sensor.

  The signal processing unit 15 converts an analog image signal output from the image sensor 14 into a digital signal (image data) and outputs the digital signal to the data bus 26.

  The RAM 16 is a volatile memory, and the image data output from the signal processing unit 15 is temporarily recorded in the RAM 16 as image data via the data bus 26. The image processing unit 17 reads the image data recorded in the RAM 16 and performs various image processing (gradation conversion processing, contour enhancement processing, white balance processing, etc.). In addition, the image processing unit 17 analyzes the image signal and detects the luminance for each pixel. Specifically, the image processing unit 17 converts image data of RGB signals into image data of luminance signals (Y signals) and color difference signals (Cr, Cb signals) (YC conversion).

  The flash memory 18 is a rewritable nonvolatile semiconductor memory. A program for controlling the electronic camera 1 is recorded in the flash memory 18 in advance. The CPU 25 executes processing of a flow shown in FIG. 5 described later as an example according to this program. The flash memory 18 stores information (including a threshold value) indicating determination criteria for the moving state of the main subject in a table (details will be described later).

  The recording I / F unit 19 is formed with a connector (not shown) for connecting a detachable recording medium 30. Then, the recording I / F unit 19 accesses the recording medium 30 connected to the connector and performs still image recording processing and the like. The recording medium 30 is, for example, a card type nonvolatile memory card. FIG. 1 shows the recording medium 30 after being connected to the connector.

  The display I / F unit 20 outputs a still image for reproduction temporarily recorded in the RAM 16, an image showing an operation menu of the electronic camera 1, and the like to the display monitor 21. In addition, the display I / F unit 20 outputs, to the display monitor 21, a through image in which the resolution of the image output by the image sensor 14 is set lower than the recording image recorded on the recording medium 30 during shooting standby. For example, the display I / F unit 20 outputs a through image to the display monitor 21 at 30 frames per second (30 fps). The display monitor 21 is composed of, for example, a liquid crystal display medium.

  The touch panel 22 detects the position of a fingertip or the like that has touched the touch panel surface. The touch panel 22 receives the operation from the photographer by outputting the detected position information to the CPU 25. The operation unit 23 has a plurality of buttons (not shown) for accepting a photographer's operation, and accepts an instruction input for operating the electronic camera 1.

  The release button 24 is used to obtain a recording image to be recorded on the recording medium 30 and a half-press operation (instruction input for starting operation such as autofocus (AF) and automatic exposure (AE) before photographing) and a full-press operation. An instruction input of “image pickup operation start” is received.

  The CPU 25 is a microprocessor that performs various calculations and overall control of the electronic camera 1. The CPU 25 controls each part of the electronic camera 1 by executing the above program. The CPU 25 also functions as a recognition unit 25a, a setting unit 25b, a motion amount detection unit 25c, a determination unit 25d, an acquisition unit 25e, and a zoom control unit 25f.

  The recognition unit 25a recognizes the main subject from the image. For example, the recognition unit 25a extracts a person's face by analyzing the image and recognizes the face as a main subject. Specifically, the recognition unit 25a extracts the skin color area as a face area based on the luminance distribution of the image signal of the image. When the recognition unit 25a detects a face, the recognition unit 25a further detects a feature portion of the face. That is, the recognition unit 25a detects facial feature parts such as eyes, nose, ears, and lips from an image by a feature point extraction process described in, for example, Japanese Patent Application Laid-Open No. 2001-16573. Accordingly, the recognition unit 25a can easily recognize the face area of the person as the main subject. Note that the recognition unit 25a may recognize a side profile of the face. Specifically, the recognition unit 25a extracts a face outline from a skin color area and a black area connected to the area based on the luminance distribution of the image signal of the image, and the shape of the face outline has central symmetry. If not, it may be detected as a profile. The recognizing unit 25a may detect a side face based on the outline of the nose, which is the outline of the face.

  In addition, the recognition unit 25a may recognize the area designated by the user input via the touch panel 22 as the main subject. Thereby, the recognition unit 25a can set the area designated by the user as the main subject.

  Alternatively, the recognition unit 25a may separate the main subject and the background by quantizing the image data of the image and recognize the main subject. Specifically, in order to binarize the image data, the recognition unit 25a selects the brightness of a pixel that serves as a binarization reference based on the luminance distribution of the image data. The recognizing unit 25a binarizes the image data by setting the pixel value brighter than the reference pixel value as white and the dark pixel value below the reference as black based on the brightness of the pixel. . As a result, the recognition unit 25a can obtain an image in which the area indicating the main subject and the area indicating the background are separated.

  The setting unit 25b sets a plurality of observation areas in the area of the main subject in order to detect the movement of the main subject moving in any direction within the shooting screen. Specifically, the setting unit 25b sets, for example, characteristic parts such as eyes, nose, ears, and lips recognized by the recognition unit 25a in the observation region. Alternatively, the setting unit 25b may set a region including the midpoint of each side of the rectangular frame surrounding the face region as the observation region, as shown in FIG.

  FIG. 2 is a diagram for explaining an example of the observation region setting process. FIG. 2 schematically shows one frame (through image) in which the main subject (person P1) runs from the right to the left on the paper in the shooting screen. Here, the recognition unit 25a extracts a face area and sets a rectangular frame W1 surrounding the face area. Then, the setting unit 25b sets, for example, an area including the midpoint of each side of the rectangular frame W1 as the observation area. Specifically, the setting unit 25b sets observation areas (S1, S2, S3, and S4) at four locations on the upper, lower, left, and right sides of the face area of the person P1, which is the main subject.

  The motion amount detection unit 25c detects the motion amount for each observation region based on a plurality of through images acquired in time series.

  FIG. 3 is a diagram for explaining an example of a motion amount detection process for each observation region. The imaging screen shown in FIG. 3 corresponds to the imaging surface of the imaging device 14, and as an example, is divided into 30 parts vertically, 20 parts horizontally, and 600 parts as a whole. FIG. 3A illustrates each pixel corresponding to the image of one frame shown in FIG. The motion amount detection unit 25c detects, for example, the motion amount of each observation area of the main subject between frames based on the movement amount of the number of pixels in the image. FIG. 3B illustrates the respective pixels in association with each other on the image of the next frame (current frame) of the frame illustrated in FIG. For easy understanding, in FIG. 3B, the rectangular frame W1 of the previous frame (FIG. 3A) and the person P1 (dotted line in the figure) are also drawn in association with each other. In FIG. 3B, the motion vectors (arrows in the figure) are schematically superimposed and drawn.

  Based on the luminance of each pixel detected by the image processing unit 17, the motion amount detection unit 25 c performs the color (luminance) of four pixels in the observation region (S 1, S 2, S 3, S 4 (reference number omitted)). The direction of movement is detected in pixel units. In the example of FIG. 3B, since the entire observation region has moved by 8 pixels in the direction of the motion vector, the motion amount detection unit 25c detects the movement of the person P1. Here, the movement amount detection unit 25c may detect the movement amount of the observation region when the movement amount of the observation region exceeds a preset threshold value between consecutive frames. That is, the motion amount detection unit 25c detects the motion amount of the observation region based on the movement amount of the observation region. Thereby, the motion amount detection unit 25c can detect the motion amount using the threshold value as a determination criterion. Here, the threshold is, for example, the amount of movement of the observation region on the pixel, and in the case of FIG. In actual application, the threshold value may be changed as appropriate. Further, in this embodiment, in order to make the explanation easy to understand, the threshold value is associated with the movement amount on the pixel in the observation region, but the movement distance set in advance is associated with the position coordinate in the imaging screen. It may be set as a threshold value.

  FIG. 4 is a diagram for explaining another example of the motion amount detection process for each observation region. In FIG. 4, it is assumed that the moving direction of the main subject is the optical axis direction (including a direction having a component in the optical axis direction of the photographing optical system 10). 4A and 4B show a through image in a time series in a scene in which the main subject (person P2) moves in the optical axis L direction (vertical direction in the drawing: z direction in the drawing) of the photographing optical system 10. FIG. ing. The recognition unit 25a detects the face area of the person P2 and sets a rectangular frame W1. Here, FIG. 4C is a diagram obtained by extracting and enlarging the region in the rectangular frame W1 of FIGS. 4A and 4B. In FIG. 4C, the left side of the drawing is a diagram showing a region in the rectangular frame W1 of FIG. 4A, and the right side of the drawing is a diagram showing a region in the rectangular frame W1 of FIG. 4B.

  The setting unit 25b sets the observation areas S1 to S4 in the rectangular frame W1 in the same manner as described with reference to FIG. Here, when the person P2 moves from the state shown in FIG. 4A to the state shown in FIG. 4B, the moving direction of the person P2 is a direction approaching the photographer. At this time, the movement direction of each observation region (S1 to S4) is a direction in which the rectangular frame W1 is enlarged on the photographing screen, and is a direction toward the outside as indicated by an arrow in FIG. Direction ”). When the moving direction of the person P2 moves away from the photographer, the moving direction of each observation area (S1 to S4) is a direction in which the rectangular frame W1 is reduced on the shooting screen and is a direction toward the inside (hereinafter referred to as “negative”). Direction ”). Therefore, when the movement direction of each observation region (S1 to S4) is a positive direction or a negative direction, the motion amount detection unit 25c detects the movement direction of the person P2 as the optical axis direction.

  That is, when the setting unit 25b sets four observation areas in the main subject, the movement amount detection unit 25c sets the movement direction of the main subject in the shooting screen as the vertical direction, the left-right direction, the diagonal direction, and the optical axis direction. It is possible to easily detect which direction (the front-rear direction). Note that the setting unit 25b sets four observation regions as an example, and is not limited to four.

  The determination unit 25d determines the moving state of the main subject based on the amount of movement for each observation region. Specifically, the determination unit 25d determines whether the main subject has moved in any direction within the shooting screen based on the amount of movement for each observation region between the current frame and the previous frame, or The moving state such as whether the main subject is stationary is determined.

  When the determination unit determines that the observation region is stationary, the acquisition unit 25e causes the image sensor 14 to acquire the main image. Specifically, after performing AE and AF, the acquisition unit 25e performs automatic shooting that controls the shooting conditions such as the charge accumulation time via a timing generator (not shown) and causes the image sensor 14 to acquire the main image. Do.

  The zoom control unit 25f changes the zoom magnification. Specifically, the zoom control unit 25f instructs the lens driving unit 11 to change the zoom magnification. Accordingly, the zoom control unit 25 f changes the zoom magnification of the zoom lens of the photographing optical system 10 via the lens driving unit 11. In addition, when the determination unit 25d determines that the moving state of the main subject is movement in a direction having a component in the optical axis direction of the photographing optical system 10, the zoom control unit 25f changes the zoom magnification. Thereby, the zoom control unit 25f can cancel the movement amount of the observation region (details will be described later).

  Further, the CPU 25 detects the movement of the main subject due to the difference between the current frame and the previous frame, and tracks the main subject in the image. Specifically, as an example, the CPU 25 divides the through image into blocks of 16 pixels × 16 pixels, and calculates a pixel in which the difference signal between frames of each pixel is equal to or greater than a preset threshold value for the difference signal for each block. Thus, the movement of the main subject is detected. Note that the CPU 25 may perform inter-frame difference by thinning out and reading through images.

  Next, an example of the operation at the time of photographing with the electronic camera 1 will be described. FIG. 5 is a flowchart showing an example of the operation of the electronic camera 1. In the following operation example, after the power is turned on, the CPU 25 first drives the imaging device 14 to start capturing a through image. After that, when the operation unit 23 receives an instruction input of “blur suppression mode” as the shooting mode, the CPU 25 starts the processing of the flow illustrated in FIG. 5. It is assumed that the number of pixels of the image sensor 14 is larger than the number of pixels described in FIG. Further, the CPU 25 may accept an instruction input for setting an “auto zoom mode” in which the zoom magnification is changed without the photographer's operation as a mode below the “blur suppression mode”.

  FIG. 6 is a sequence diagram illustrating an example of a photographing operation in the shake suppression mode. As a shooting scene, a scene in which a main subject (person P3) is playing soccer is taken as an example. In FIG. 6A, the process of the flow shown in FIG. 5 is represented along the time axis t (unit: second) from the start to the end. In FIG. 6B, four through images ((1) to (4) in the drawing) are extracted and drawn in time series in association with the processing of the flow shown in FIG.

  Step S101: The recognition unit 25a of the CPU 25 performs recognition processing of the main subject. Specifically, the recognition unit 25a extracts the skin color area as a face area based on the luminance distribution of the image signal of the through image. Then, the recognizing unit 25a detects a feature portion of the face from the image by the feature point extraction process described above. Further, the recognizing unit 25a sets a rectangular frame W1 surrounding the face area of the person P3 based on the positional relationship of the facial feature parts (see (1) in FIG. 6B).

  Step S102: If the main subject has been recognized (step S102: Yes), the CPU 25 proceeds to the process of step S103. On the other hand, when the main subject cannot be recognized (step S102: No), the CPU 25 ends the process of the flow shown in FIG.

  Step S103: The setting unit 25b of the CPU 25 performs observation area setting processing. Specifically, the setting unit 25b sets the observation areas (S1, S2, S3, S4) at four locations on the top, bottom, left, and right of the face area of the person P3 that is the main subject ((1) in FIG. 6B). ) Here, the CPU 25 causes the rectangular frame W1 to be superimposed and displayed on the through image displayed on the display monitor 21. On the other hand, the CPU 25 does not require the photographer to visually recognize the observation area, and therefore does not display the observation area on the display monitor 21. The setting unit 25b may set facial features such as the eyes, nose, and lips of the person P3 as an observation area.

  Step S104: The CPU 25 performs a main subject tracking process. Specifically, the CPU 25 detects the movement of the main subject based on the inter-frame difference between the current frame and the previous frame, and tracks the main subject in the image. Further, the CPU 25 calculates a motion vector (including direction and size) based on the position of the main subject to be tracked in the current frame and the position of the main subject to be tracked in the previous frame. Note that the diagrams (3) and (4) in FIG. 6B correspond to the processing from step S104 to step S110.

Step S105: The CPU 25 determines whether or not the main subject has been tracked between frames. If the main subject disappears in the shooting screen (step S105: No ), the CPU 25 ends the process of the flow shown in FIG. On the other hand, when the main subject does not disappear in the shooting screen (step S105: Yes ), the CPU 25 proceeds to the process of step S106.

  Step S106: The movement amount detection unit 25c of the CPU 25 calculates a movement amount for each observation region between frames. Specifically, the motion amount detection unit 25c detects the amount of movement of the main subject for each observation region between frames from the current frame and the previous frame, based on the amount of movement of the number of pixels in the image.

  Step S107: The determination unit 25d of the CPU 25 determines whether or not the movement amount for each observation region is equal to or less than a threshold value. Specifically, the determination unit 25d refers to the threshold value recorded in the flash memory 18, and the main subject moves in any direction within the shooting screen based on the amount of movement for each observation region determined from the amount of movement. Whether or not the main subject is stationary is determined. Here, if the movement amount for each observation region is equal to or smaller than the threshold value, the determination unit 25d determines that the main subject is in a stationary state. Therefore, when the movement amount for each observation area is equal to or less than the threshold (step S107: Yes), the CPU 25 proceeds to a photographing process in step S111 described later. On the other hand, when the movement amount for each observation region is larger than the threshold (step S107: No), the CPU 25 proceeds to the process of step S108. Note that the determination unit 25d may perform the determination with reference to information indicating the determination criterion of the moving state of the main subject recorded in the flash memory 18.

  FIG. 7 is a diagram illustrating an example of a criterion for determining the moving state of the main subject. FIG. 7A is a diagram illustrating an example of a criterion for determining the moving state of the main subject when the main subject moves in the optical axis direction. FIG. 7A shows the relationship between the number of horizontal pixels of the main subject, the stationary state, and the allowable threshold. Here, for the sake of simplicity, the horizontal width of the main subject may be the horizontal width of the rectangular frame W1 shown in FIG.

  For example, if the number of horizontal pixels in the previous frame is 10 pixels and the number of horizontal pixels in the current frame is 10, the determination unit 25d determines that the main subject is Determine that it is stationary.

  On the other hand, as shown in FIG. 4, when the moving direction of the main subject approaches the photographer in the optical axis direction, the ratio of the main subject (face area) in the shooting screen increases. For example, when the number of horizontal pixels in the previous frame is 10 pixels, but the number of pixels in the current frame is 30 pixels in accordance with the movement, the determination unit 25d determines that the movement amount for each observation area in the next inter-frame difference is For example, if it is 6 pixels or less, it is determined that the main subject is stationary. Thereby, the determination unit 25d can determine the movement state of the main subject more accurately. This is because the ratio of the main subject in the shooting screen is, for example, when FIG. 4 (a) is compared with FIG. 4 (b), the case of FIG. This is because even if the movement amount of the number of pixels is the same as the ratio is small, the movement is larger than in the case of FIG.

  FIG. 7B shows the relationship between the shutter speed and the threshold value for allowing the main subject to be stationary. The faster the shutter speed, the easier it is to shoot a moving subject stationary. Accordingly, the determination unit 25d may determine the movement state of the main subject by further adding the number of pixels corresponding to the set value of the shutter speed to the threshold number of pixels. Thus, the determination unit 25d can determine the moving state of the main subject by increasing the threshold value as the shutter speed setting value increases.

  The number of pixels shown in FIG. 7 is an example, and is not limited to these numerical values. In FIG. 7B, the determination unit 25d does not further add the number of pixels corresponding to the shutter speed setting value to the threshold number of pixels, but multiplies a predetermined proportional coefficient according to the shutter speed setting value. You may make it do.

  Step S108: When the moving direction of the main subject is the optical axis direction (step S108: Yes), the CPU 25 proceeds to the process of step S109. On the other hand, when the moving direction of the main subject is not the optical axis direction (step S108: No), the CPU 25 returns to the process of step S104 and continues the tracking process.

  Step S109: The CPU 25 determines whether or not the automatic zoom mode is set. When the automatic zoom mode is set (step S109: Yes), the CPU 25 proceeds to the process of step S110. On the other hand, when the automatic zoom mode is not set (step S109: No), the CPU 25 returns to the process of step S104 and continues the tracking process.

  Step S110: The zoom control unit 25f of the CPU 25 changes the zoom magnification. Note that in the case of the shooting scene taken up in FIG. 6, the main subject (person P3) has not moved in the optical axis direction, and therefore the processing in steps S109 and S110 is not performed. Therefore, in this embodiment, the details of the processing in steps S109 and S110 will be described separately by taking up movement of the main subject in the optical axis direction in another shooting scene.

  Step S111: The acquisition unit 25e of the CPU 25 causes the image sensor 14 to acquire a main image by automatic shooting. Specifically, the acquisition unit 25e controls the imaging conditions such as the charge accumulation time via a timing generator (not shown) and causes the image sensor 14 to acquire the main image (in (4) of FIG. 6B). (See figure). Then, the CPU 25 ends the process of the flow shown in FIG. Thereafter, the CPU 25 records the main image on the recording medium 30.

  Next, an example of shooting in a shooting scene in which the main subject moves in the optical axis direction will be described.

  FIG. 8 is a diagram illustrating an example of a shooting scene in which the main subject moves in the optical axis direction. FIG. 8A shows a state where the main subject (person P4) is on the swing 50. FIG. Here, at the points (A) and (C), the motion vector of the main subject riding on the swing 50 once becomes zero, and the main subject is temporarily stationary. Thereafter, the motion vector is reversed, and the main subject starts moving on the swing 50 again. At the point (B), the motion vector is maximum.

  FIG. 8B is a front view (through image) of the main subject (person P4) riding on the swing 50. FIG. FIG. 8B shows the point (C) in FIG.

  For example, as shown in FIG. 8, when the moving direction of the main subject approaches the photographer in the optical axis direction, the CPU 25 proceeds to the process of step S109. Furthermore, when the automatic zoom mode is not set (step S109: No), the CPU 25 returns to the process of step S104. For example, when the main subject (person P4) reaches the point shown in FIG. 8B (the point (C) in FIG. 8A) while repeating the processing from step S104 to step S109, the main subject Is temporarily stationary. In this case, in the next process of step S107, the determination unit 25d determines that the movement amount for each observation region is equal to or less than the threshold (step S107: Yes), and the CPU 25 proceeds to the imaging process of step S111. Then, the CPU 25 ends the flow process (blur suppression mode) shown in FIG. Thereafter, the CPU 25 records the main image on the recording medium 30.

  Next, a case where the automatic zoom mode is set will be described. FIG. 9 is a diagram illustrating an example of the automatic zoom mode. FIG. 9A shows a positive direction of movement of the main subject (P4) in the previous frame (movement from (A) to (C) shown in FIG. 8A). As shown in FIG. 9A, when the moving direction of the main subject approaches the photographer in the optical axis direction, the CPU 25 proceeds to the process of step S109. Furthermore, when the automatic zoom mode is set (step S109: Yes), the CPU 25 proceeds to the process of step S110.

  The zoom control unit 25f shifts the zoom lens of the photographing optical system 10 to the wide-angle side via the lens driving unit 11 (FIG. 9B). In FIG. 9B, the moving direction of each observation region is represented by a solid line arrow (motion vector). A dotted arrow schematically represents shifting the zoom lens to the wide angle side.

  CPU25 returns to the process of step S104 again after the process of step S110. Then, the CPU 25 performs a tracking process to obtain an image of the current frame. At this time, the main subject of the current frame is shown in FIG. The motion amount detection unit 25c detects the movement amount of the main subject for each observation region between frames from the current frame and the previous frame, based on the movement amount of the number of pixels in the image. The determination unit 25d determines again the moving state of the main subject based on the amount of movement for each observation region (step S106). For example, the determination unit 25d compares the main subject shown in FIG. 9A with the main subject shown in FIG. 9C. If the amount of movement for each observation area is equal to or less than the threshold (step S107: Yes), the main subject appears to be stationary, so the CPU 25 can move to the photographing process in step S111. Then, the CPU 25 ends the process of the flow shown in FIG. Thereafter, the CPU 25 records the main image on the recording medium 30.

  FIG. 10 is a diagram for explaining another example of the automatic zoom mode. FIG. 10A shows a negative direction of movement of the main subject (P4) in the previous frame (movement from (C) to (A) shown in FIG. 8A). As shown in FIG. 10A, when the moving direction of the main subject is away from the photographer in the optical axis direction, the CPU 25 proceeds to the process of step S109. Furthermore, when the automatic zoom mode is set (step S109: Yes), the CPU 25 proceeds to the process of step S110.

  The zoom control unit 25f shifts the zoom lens of the photographing optical system 10 to the telephoto side via the lens driving unit 11 (FIG. 10B). In FIG. 10B, the moving direction of each observation region is represented by a solid line arrow (motion vector). A dotted arrow schematically represents shifting the zoom lens to the telephoto side.

  CPU25 returns to the process of step S104 again after the process of step S110. Then, the CPU 25 performs a tracking process to obtain an image of the current frame. At this time, the main subject of the current frame is shown in FIG. The motion amount detection unit 25c detects the movement amount of the main subject for each observation region between frames from the current frame and the previous frame, based on the movement amount of the number of pixels in the image. The determination unit 25d determines again the moving state of the main subject based on the amount of movement for each observation region (step S106). For example, the determination unit 25d compares the main subject shown in FIG. 10A with the main subject shown in FIG. If the amount of movement for each observation area is equal to or less than the threshold (step S107: Yes), the main subject appears to be stationary, so the CPU 25 can move to the photographing process in step S111. Then, the CPU 25 ends the process of the flow shown in FIG. Thereafter, the CPU 25 records the main image on the recording medium 30.

As described above, the electronic camera 1 of the present embodiment can determine the moving state of the main subject by setting the observation area even when the main subject moves in any direction within the shooting screen. it can. As a result, the electronic camera 1 automatically acquires the main image when the main subject is stationary (including when the main subject is apparently stationary). Therefore, the electronic camera 1 can provide a photographing unit that reduces blurring of the main subject.
(Supplementary items of the above embodiment)
(1) In the above embodiment, the case where the zoom magnification of the zoom lens of the photographing optical system 10 is changed in the automatic zoom mode has been described. Here, the zoom control unit 25f may change the zoom magnification of the zoom lens according to the user's manual operation in the shake suppression mode. In this case, the setting unit 25b sets the observation area again for the main subject after changing the zoom magnification. Further, the CPU 25 resets the threshold according to the ratio of the main subject in the shooting screen after changing the zoom magnification. Thereby, even if the zoom magnification changes according to the user's manual operation, the motion amount detection unit 25c can detect the motion amount using the reset threshold as a determination criterion.

  (2) In the above embodiment, the recognition unit 25a recognizes a face as a main subject. Here, in the present embodiment, an image in which a person is registered in advance may be recorded in the flash memory 18. Thereby, when there are a plurality of persons in the shooting screen, the recognition unit 25a may collate the face recognized in the shooting screen with the face registered as a person and use only the registered person as the main subject.

  (3) In the above embodiment, shooting was performed without moving the electronic camera 1. In the present embodiment, the above-described photographing unit may be applied to panning photographing.

  (4) The program of the present invention is executed on the CPU 25 of the electronic camera 1, for example. In the above embodiment, the program of the present invention is recorded in the flash memory 18 in advance. In the present embodiment, for example, the program of the present invention may be recorded on the recording medium 30 and the program recorded on the recording medium 30 may be recorded on the flash memory 18. Thereby, in the electronic camera 1, it becomes possible to apply the program of this invention as firmware which adds a new function.

  (5) The program of the present invention may be applied to a camera system that combines a so-called web camera and a computer. In this case, the program of the present invention may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed.

  (6) Note that the “computer system” in (5) includes an OS (Operating System) and hardware of peripheral devices. Further, the “computer-readable recording medium” in (5) means a portable recording medium such as a flexible disk, a magneto-optical disk, an optical disk, and a memory card, and a storage device such as a hard disk built in the computer system. . Further, the above-mentioned “computer-readable recording medium” refers to a program that is dynamically executed for a short time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. What is held, and what holds a program for a certain period of time, such as a volatile memory inside a computer system serving as a server or client in that case, may be included. Further, the above program may be for realizing a part of the above-described functions, and further, may be realized by combining the above-described functions with a program already recorded in the computer system. .

DESCRIPTION OF SYMBOLS 1 ... Electronic camera, 14 ... Image sensor, 25a ... Recognition part, 25b ... Setting part, 25c ... Motion amount detection part, 25d ... Determination part, 30 ... Recording medium

Claims (9)

An imaging unit that captures a subject image and outputs image data ;
A main subject area detection unit for detecting a main subject area where a main subject exists using the image data ;
A setting unit for setting a plurality of detection areas in the main subject area ;
Using a plurality of the image data picked up at different times, a motion detection unit for detecting movements of the plurality of detection regions set in the main subject region ;
A control unit that controls the imaging unit to output image data for recording when the movements of the plurality of detection areas detected by the motion detection unit are smaller than a predetermined threshold value. camera. The electronic camera according to claim 1 ,
The main subject region detection unit detects a human face region as the main subject region,
The electronic camera according to claim 1, wherein the setting unit sets a feature portion of the face of the person as the detection area . An electronic camera according to claim 2,
The electronic camera according to claim 1, wherein the detection area includes at least one of an eye part, a nose part, an ear part, and a lip part of the face of the person . An electronic camera as claimed in any one of claims 1 to 3,
The control unit increases the predetermined threshold as the shutter speed increases . The electronic camera according to claim 4 ,
The electronic camera according to claim 1, wherein the control unit increases the predetermined threshold as the lateral width of the main subject region increases . An electronic camera as claimed in any one of claims 1 to 5,
A zoom control unit for changing the zoom magnification of the imaging optical system;
The zoom control unit changes the zoom magnification of the imaging optical system when the motion detection unit detects that the main subject is moving in the same direction as the optical axis direction in the imaging optical system. And an electronic camera. An electronic camera according to claim 6,
The control unit detects again the movement of the detection area in accordance with the change of the zoom magnification of the imaging optical system, and when the movement of the plurality of detection areas is smaller than a predetermined threshold, the imaging unit detects image data for recording. An electronic camera characterized by being controlled so as to output . Imaging processing for capturing a subject image and outputting image data ;
A main subject region detection process for detecting a main subject region where a main subject exists using the image data ;
A setting process for setting a plurality of detection areas in the main subject area ;
Using a plurality of the image data captured at different times, a motion detection process for detecting movements of the plurality of detection areas set in the main subject area ;
A control process for performing control to output the image data for recording by performing the imaging process when the motion of the plurality of detection areas detected by the motion detection process is smaller than a predetermined threshold;
A program that causes a computer to execute. Imaging processing for capturing a subject image and outputting image data ;
A main subject region detection process for detecting a main subject region where a main subject exists using the image data ;
A setting process for setting a plurality of detection areas in the main subject area ;
Using a plurality of the image data captured at different times, a motion detection process for detecting movements of the plurality of detection areas set in the main subject area ;
A control process for performing control to output the image data for recording by performing the imaging process when the motion of the plurality of detection areas detected by the motion detection process is smaller than a predetermined threshold;
A computer-readable recording medium having recorded thereon instructions for causing a computer to execute.

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