JP5341655B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an image pickup apparatus and a control method thereof, and more particularly to an image pickup apparatus capable of shooting in a direction different from the direction of the center of an optical axis by controlling an image cutout position and a control method thereof. is there.

  Some imaging devices such as digital cameras and digital video cameras have a display device having a finder function on the back of the imaging device. The photographer can photograph a desired image or video by photographing while viewing the subject image displayed on the display device.

  In high-angle shooting in which the imaging device is held at a position higher than the photographer's eye level or in low-angle shooting in which the imaging device is held in a position lower than the photographer's eye level, the photographer May not ensure the visibility of the display screen of the display device provided in the imaging device. FIG. 6B is a diagram illustrating the positional relationship between the photographer and the display device provided in the imaging device, for example, during high-angle shooting (i), normal shooting (ii), and low-angle shooting (iii). It is. In the normal shooting of (ii), the display device provided in the imaging device faces the photographer's eyes, but in the high angle shooting (i) and the low angle shooting (iii), the display device is provided in the imaging device. The displayed display device is positioned in an oblique direction with respect to the photographer. That is, for example, when the display device is an LCD, it is difficult to recognize the luminance difference or contrast ratio of the display content of the display device from outside the viewing angle range unique to the LCD. Further, for example, even when a display device with a wide viewing angle and a wide viewing angle is provided, when viewing the display screen from an oblique direction with respect to the display device, it is difficult to determine the angle of view and composition of shooting.

  Various proposals have been made for the problem of visibility of a display device provided in an imaging apparatus during such high-angle shooting or low-angle shooting. Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique that enables a photographer to ensure the visibility of a display device by providing the image pickup device with an opening / closing mechanism of a display device provided in the image pickup device. Japanese Patent Application Laid-Open No. 2004-228561 provides a technique for rotating a display control device provided in an imaging device in the imaging device, and controlling a rotation angle of the display device from tilt angle information and position (height) information of the imaging device. Is disclosed. In the imaging devices disclosed in Patent Documents 1 and 2, for example, as shown in FIG. 6C, the imaging device is used during high angle shooting (i), normal shooting (ii), and low angle shooting (iii). The provided display device faces the photographer's eyes. For this reason, the photographer can take a picture while confirming the display device facing the camera without being aware of the viewing angle of the display device provided in the imaging device.

JP 2001-94845 A JP 2007-180663 A

  However, in the imaging devices described in Patent Documents 1 and 2, in order to make the display device movable, it is necessary to provide a mechanical movable mechanism such as an opening / closing mechanism and a rotation mechanism in the imaging device, which increases the size of the imaging device. There is a problem. Further, there is a problem that the manufacturing cost increases due to an increase in the number of mechanisms.

  The present invention has been made in view of the above-described problems of the prior art, and imaging of a display device during high-angle shooting or low-angle shooting without providing a mechanical movable mechanism in the imaging device. The purpose is to improve the visibility to the person.

In order to achieve the above object, an imaging apparatus of the present invention has the following configuration.
Comprising imaging means for imaging a subject, a clipping means for cutting out a part of the area of the image captured by the imaging means, display means for displaying an image of a part of the area cut out by the cutout section, a cut-out In the case of high-angle shooting in which the image pickup device is held at a position higher than the eye level of the photographer, the center of a part of the area cut out by the cut-out means is the center of the image picked up by the image pickup means. In the case of low-angle shooting in which the image pickup device is set at a position lower than the eye level of the photographer and set at a lower position, the center of a part of the area cut out by the cut-out means is set by the image pickup means. It is characterized by being set to a position above the center of the captured image.

  According to the present invention, it is possible to improve the visibility of a display device to a photographer during high-angle shooting or low-angle shooting without providing a mechanical movable mechanism in the imaging device.

1 is a block diagram illustrating an example of a functional configuration of an imaging apparatus according to an embodiment of the present invention. 5 is a flowchart of image cutout processing according to the first embodiment. The figure for demonstrating an image cut-out process. 10 is a flowchart of image cutout processing according to the second embodiment. The figure for demonstrating the acquisition process of space position angle information. The figure which imitated the positional relationship of a photographer and the display apparatus provided in the imaging device.

  Hereinafter, preferred and exemplary embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment described below, the present invention is applied to a digital camera as an example of an imaging apparatus provided so that a shooting mode corresponding to high angle shooting or low angle shooting can be selected by a user. It is an example.

(Embodiment 1)
In the digital camera 100 shown in FIG. 1, the imaging lens 101 is an optical system for taking in information on a subject into the digital camera 100. The imaging lens 101 includes, for example, a zoom lens, a focus adjustment lens, and the like, and is used for enlarging / reducing a subject image and focusing on the subject image. The image sensor 102 photoelectrically converts the subject image formed by the imaging lens 101 to generate an analog image signal, and passes it to the A / D converter 103. The A / D conversion unit 103 performs A / D conversion on the input analog image signal and passes the output digital image data to the image processing unit 104.

  The image processing unit 104 applies conversion processing such as luminance adjustment, level correction, and resolution conversion to the input (digital) image data. In the present embodiment, an image cutout processing unit 105 is provided in the image processing unit 104. The image cutout processing unit 105 performs a process of cutting out and outputting a part of the image data input to the image processing unit 104. The image data to which the conversion process is applied by the image processing unit 104 is displayed on the image display unit 106. The image display unit 106 is a small display device such as an LCD, for example, and after the digital camera 100 is activated by the photographer operating the power SW 111, the image data captured and converted by the digital camera 100 is sequentially displayed. To do.

  The lens driving unit 107 controls the driving of the imaging lens 101 in response to, for example, an operation of the shutter SW 112 and the zoom SW 113 by the photographer. For example, the magnification lens is driven when a zoom request is made by the photographer's operation of the zoom SW 113, and the focus adjustment lens is driven when the photographer requests a focus by half-pressing the shutter SW 112.

  The control unit 108 controls the operation of each block of the digital camera 100. The control unit 108 is, for example, a CPU. The operation program of each block stored in the ROM 109 is expanded in a RAM (not shown) and executed, thereby causing the above-described blocks to perform an operation. The information stored in the ROM 109 includes not only the operation program for each block but also parameters necessary for processing of each block of the digital camera 100 and the digital camera 100 such as the number of output pixels and the focal length. The ROM 109 also stores a shooting mode described later, operation parameters of each block of the digital camera 100 corresponding to the shooting mode, information on the currently selected shooting mode, and the like.

  When an imaging request instruction is input by the photographer operating the shutter SW 112, the control unit 108 records the image data output from the image processing unit 104 on the recording medium 110. The recording medium may be removable such as a memory card, or may be incorporated such as an internal memory.

  When receiving an input by the photographer's operation of the menu SW 114, the control unit 108 reads GUI information for selecting a shooting mode from the ROM 109 and displays it on the image display unit 106. In the present embodiment, the shooting modes stored in the ROM 109 of the digital camera 100 include three shooting modes that can be selected by the photographer. One of the three shooting modes is a mode for shooting with the digital camera 100 at a normal eye level of the photographer, and is set to this mode in the initial state of the imaging apparatus. The remaining two shooting modes are “high angle shooting mode” in which the digital camera 100 is held above the eye level of the photographer and the front subject is photographed, and the digital camera 100 is placed below the eye level of the photographer. This is a “low-angle shooting mode” in which the subject in front is photographed. In addition, after the shooting mode is determined by the photographer in the present invention, the control unit 108 reads from the ROM 109 operation parameters that are set for each block of the digital camera 100 corresponding to the selected shooting mode, and stores the operation parameters in each block. Apply.

The image clipping process in the digital camera according to the first embodiment having the above-described configuration will be described in detail with reference to the flowchart of FIG.
In step S <b> 201, the control unit 108 determines whether the currently selected shooting mode of the digital camera 100 stored in the ROM 109 is “high angle shooting mode” or “low angle shooting mode”. If the currently selected shooting mode is neither the “high angle shooting mode” nor the “low angle shooting mode”, the control unit 108 determines whether the digital zoom is used in the current zoom setting of the digital camera 100 in S202. To do. When the digital zoom is used, the process proceeds to S203, and the control unit 108 sets the center of the captured image data as the center for cutting out an image for enlargement. Further, when the digital zoom is not used, it is not necessary to perform image clipping.

  When the currently selected shooting mode is “high angle shooting mode” or “low angle shooting mode”, the control unit 108 acquires information on the number of cutout pixels stored in the ROM 109 and the current optical system state. Information on the focal length is obtained from (S204). The information on the number of cut-out pixels is information included in each setting of “high angle shooting mode” and “low angle shooting mode” stored in the ROM 109, for example, and is the pixel of image data cut out from the captured image data Point to a number. Further, the information about the number of cut-out pixels may not be included in the setting of the shooting mode, and for example, the photographer may be able to set it.

  Next, the control unit 108 determines whether or not the currently selected shooting mode stored in the ROM 109 is the “high angle shooting mode” (S205). When the currently selected shooting mode is "High Angle Shooting Mode", the center of the range to cut out the image from the captured image data (cutting center) is below the optical axis center (center of the image data) (S206). In the case of the “low angle shooting mode”, the cut-out center is set to a position above the optical axis center (S207).

  Here, the relationship between the cutting center and the optical axis center will be described with reference to FIG. FIG. 6A shows the digital camera 100 so that the image display unit 106 faces the photographer in each of high angle shooting (i), normal shooting (ii), and low angle shooting (iii). It is the figure which showed the state which gripped. First, in normal shooting, for example, the direction 611 of the optical axis center and the direction 612 of the subject are the same as shown in the figure. Since the subject direction 612 is the optimum direction as the cutout center of the image data to be captured, when the digital zoom is used in normal shooting, the cutout center of the image coincides with the optical axis center. Next, in the case of high-angle shooting, when the digital camera 100 is held so that the image display unit 106 faces the photographer, the direction 601 about the optical axis and the direction 602 of the subject are different. For example, when the subject direction 602 is the front direction of the photographer as shown in the figure, the cutout center is below the optical axis center, that is, the subject direction 602 is the cutout center. Similarly, in the case of low-angle shooting, when the digital camera 100 is held so that the image display unit 106 faces the photographer, the direction 621 about the optical axis and the direction 622 of the subject are different. For example, when the subject direction 622 is the front direction of the photographer as shown in the figure, the cut-out center is above the optical axis center, that is, the subject direction 602 is the cut-out center. As a result, it is possible to perform photographing centering on the subject image while holding the digital camera 100 so that the image display unit 106 faces the photographer, that is, in a state where visibility is ensured.

  In step S208, the control unit 108 acquires information on an inclination angle that is an angle formed by the direction of the center of the optical axis and the direction of the cutting center (inclination angle detection). The information on the tilt angle may be stored in the ROM 109 as setting information of “high angle shooting mode” and “low angle shooting mode”, or may be set by the photographer and stored in the ROM 109, for example.

  In step S <b> 209, the control unit 108 calculates the position of the cut-out center from information on the tilt angle, the focal length, and the number of pixels of the captured image data. Here, a method of calculating the position of the cut-out center will be described with reference to FIG. 3 taking the “high angle shooting mode” as an example. In FIG. 3A, the optical axis center direction 301 and the cut-out center direction 302 of the digital camera 100 form an inclination angle Θ, and half the vertical field angle derived from the focal length information. Assuming α, the imaging range captured by the imaging element 102 is represented by 304. In the imaging range 304, the cutout range corresponds to 303. FIG. 3B shows the image data imaged at this time, the entire imaged image data is the imaging range 304, and the rectangular area represented by diagonal lines is the cutout range 303. A point O is the center of the image data to be captured, and corresponds to the center of the optical axis. Further, the point O ′ is the cut-out center to be calculated. At this time, as the distance X between the cut-out center O ′ and the optical axis center O, when using the inclination angle Θ, the angle of view α, and the number of pixels Y that is half the number of vertical pixels of the captured image data, X = Y · tan Θ / Calculated by tanα. In other words, the calculated cut-out center O ′ is a point shifted by X downward in the vertical direction with respect to the optical axis center in the “high angle shooting mode”.

  In step S210, the control unit 108 determines whether or not the cutout range centered on the calculated cutout center is an area that can be cut out, that is, whether or not the entire cutout range is included in the captured image data area. To do. Specifically, in FIG. 3B, when the number of pixels Z that is half of the number of vertical pixels of the cutout range 303 (vertical component of the number of cutout pixels) is used, an area (imaging range 304) that can be cut out. ) Is included in X ≦ Y−Z.

  If the cutout range is within the cutout area, the control unit 108 moves the process to S213. When the cutout range does not fall within the cutout area, the control unit 108 sets the cutout center and the cutout range at a limit position (for example, (b) in FIG. So that X = Y-Z (S211). Further, in step S212, the control unit 108 reads out a screen display indicating that the cutout range has been changed from the ROM 109, for example, because the cutout range determined based on the set tilt angle value is not included in the image display unit. 106. The screen display may be, for example, a text notification, or a mark indicating that the cutout range has been changed to a part of the image display unit 106.

  In step S <b> 213, the control unit 108 performs a clipping process from the captured image data according to the clipping range set in the image clipping processing unit 105. The image data to which the clipping process is applied is subjected to various conversion processes by the image processing unit 104 and then displayed on the image display unit 106.

  As described above, according to the present embodiment, for example, when a photographer holds a digital camera at a position different from the eye level of the photographer and performs photographing, the digital camera can be used without using a mechanical mechanism. It is possible to shoot in a state where the visibility of the display unit provided is ensured. Specifically, for example, when a digital camera is held above the eye level of the photographer and shot, an image taken around a point lower than the optical axis center of the digital camera is cut out to obtain an optical axis. It is possible to shoot an image centered on a different direction from. In addition, for example, it is possible to perform forward shooting in a state where the display unit of the digital camera is directly facing the photographer and the visibility is ensured.

(Embodiment 2)
In addition to the configuration of the digital camera of the first embodiment, the digital camera of the second embodiment further includes an acceleration sensor 121 that detects the tilt angle of the digital camera and an atmospheric pressure sensor 122 that detects height information of the digital camera.

The image clipping process in the digital camera of the second embodiment having such a configuration will be described in detail with reference to the flowchart of FIG. Note that the steps in FIG. 4 that perform the same processes as those in the first embodiment are denoted by the same reference numerals as those in FIG. 2 and redundant descriptions are omitted, and only the characteristic steps in the present embodiment are described.
In the present embodiment, an “angle shooting mode” is provided as a shooting mode, and the photographer can select it. “Angle shooting mode” is a summary of “high angle shooting mode” and “low angle shooting mode”. In this embodiment, when the “angle shooting mode” is selected, the control unit 108 selects “high angle” or “ It is assumed that it is “low angle” and the processing is changed.

  In step S <b> 401, the control unit 108 determines whether the currently selected shooting mode of the digital camera 100 stored in the ROM 109 is the “angle shooting mode”. If the currently selected shooting mode is not “angle shooting mode”, the control unit 108 advances the processing to S202. When the currently selected shooting mode is “angle shooting mode”, the control unit 108 acquires information on the number of cut-out pixels stored in the ROM 109 and information on the focal length from the current optical system state. Is acquired (S204).

  In step S <b> 402, the control unit 108 acquires the current height information of the digital camera 100 in the space from the atmospheric pressure sensor 122. Based on the acquired height information, the control unit 108 determines whether the current position of the digital camera 100 is “high angle” or “low angle” (S403). Specifically, a description will be given with reference to FIG. For example, when the atmospheric pressure PH that is lower than the reference atmospheric pressure P0 (atmospheric pressure at the height h) is measured by the atmospheric pressure threshold stored in the ROM 109, “high angle (higher than the height h)” is set. Similarly, when the atmospheric pressure PL that is higher than the reference atmospheric pressure P0 by the atmospheric pressure threshold stored in the ROM 109 is measured, it is determined as “low angle (lower than height h)”. As the reference atmospheric pressure, for example, the atmospheric pressure detected by the atmospheric pressure sensor 122 when the digital camera 100 is turned on, or the atmospheric pressure detected by the atmospheric pressure sensor 122 when the “angle shooting mode” is selected can be used. In this case, the control unit 108 stores information on the reference atmospheric pressure in the ROM 109 and manages it in the ROM 109 until the shooting mode is changed.

  If it is determined in S403 that it is neither “high angle” nor “low angle” (for example, the change in atmospheric pressure is equal to or less than the threshold value), the control unit 108 moves the process to S203. The control unit 108 uses the center of the optical axis as the cutout center (S203), and performs cutout processing with the number of cutout pixels associated with the “angle shooting mode” stored in the ROM 109 in S213.

  If it is determined in S403 that “high angle” or “low angle”, the control unit 108 acquires the direction of gravitational acceleration from the acceleration sensor 121, and calculates the current tilt angle of the digital camera 100 from the value (S404). ). In step S405, the extraction center is calculated from the height information (“high angle” or “low angle”), the tilt angle, the focal length, and the number of pixels of the captured image. The height information is information for determining whether the cutting center is located above or below the optical axis center. For example, in the case of “high angle”, the cutting center is below the optical axis center.

  According to the present embodiment, for example, by using the height information and the tilt angle information of the digital camera, even if the position where the digital camera is gripped is fluidly changed, it is possible to shoot in a state in which the visibility of the display unit is ensured. It becomes possible to do.

  In the present embodiment, whether the “angle shooting mode” is “high angle shooting”, “low angle shooting”, or “normal shooting” is determined based on the height information acquired by the atmospheric pressure sensor 122. However, as shown in FIG. 5B, the acceleration sensor 121 obtains the angle Θ formed by the gravitational acceleration, thereby determining whether it is “high angle shooting”, “low angle shooting”, or “normal shooting”. You may judge.

According to Embodiments 1 and 2,
(1) Prepare "High Angle Shooting Mode" and "Low Angle Shooting Mode"
(2) Whether to perform image cut-out processing based on a preset tilt angle value,
(3) “Angle shooting mode” is prepared, and height information is acquired using an atmospheric pressure sensor, and “high angle”, “low angle”, and “normal” are determined.
(4) “Angle shooting mode” is prepared, and “high angle”, “low angle”, and “normal” are judged using the value of the inclination angle detected by the acceleration sensor,
(5) The image cut-out process is performed based on the value of the inclination angle detected by the acceleration sensor.
In the embodiment of the present invention, for ease of explanation, the digital camera having (1) and (2) is described in the first embodiment, and the digital camera having (3) to (5) is described in the second embodiment. . However, the configurations (1), (3), (4), (2), and (5) can be implemented in any combination.

Claims (7)

Imaging means for imaging a subject;
Clipping means for cutting out a partial area of the image captured by the imaging means;
Anda display means for displaying an image of said part of the area cut out by the cutout section,
The clipping means is
For high angle photographing performing an imaging device imaging poised at a position higher than the height of the photographer's eye, the central part of the region cut out by the cutout unit, the image captured by the image pickup means Set to a position below the center,
In the case of low-angle shooting in which the imaging device is held at a position lower than the eye level of the photographer, an image obtained by imaging the center of the partial area cut out by the clipping unit An imaging apparatus characterized by being set at a position above the center of the image. The imaging apparatus according to claim 1, wherein the cutout unit includes a determination unit that determines a position of a center of the partial area cut out by the cutout unit. Further comprising an inclination angle detecting means for detecting an inclination angle of the imaging device;
3. The imaging according to claim 2, wherein the determination unit determines a position of a center of the partial region cut out by the cut-out unit based on an inclination angle detected by the inclination angle detection unit. apparatus. If the partial area cut out by the cut-out means centered on the position determined by the determination means does not fit within the area of the image picked up by the image pickup means, the cut-out means The imaging apparatus according to claim 2 or 3, wherein a position of a center of the partial area cut out by the cutout unit is changed and cut out so as to be within a region of the picked-up image. Further comprising an inclination angle detecting means for detecting an inclination angle of the imaging device;
Said cut-out means, on the basis of the inclination angle detected by the inclination angle detection means, the imaging states of the imaging apparatus is characterized in that to determine which of the high-angle photographing and the low-angle shot The imaging device according to any one of claims 1 to 4 . Further comprising height detection means for detecting height information of the imaging device;
Said cut-out means includes a wherein based on the height information detected by the height detecting unit, the imaging states of the imaging apparatus to determine which one of the high-angle photographing and the low-angle shot The imaging device according to any one of claims 1 to 4 . A method for controlling an imaging apparatus including an imaging means for imaging a subject,
A clipping step in which the clipping unit cuts out a part of the image captured by the imaging unit;
Display means having a display step of displaying an image of said part of the area cut out by the cutting process step,
In the cutting out step, the cutting out means
In the case of high-angle shooting in which the image pickup device is held at a position higher than the eye level of the photographer, the center of the partial area cut out by the cut-out process is the center of the image picked up by the image pickup means. Set to a position below the center,
In the case of low-angle shooting in which the imaging device is held at a position lower than the eye level of the photographer, an image obtained by imaging the center of the partial area cut out by the clipping unit A method for controlling an image pickup apparatus, wherein the position is set to a position above the center of the image pickup apparatus.

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