JP2010085699A - Auto focus system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an auto focus (AF) system which is applied to a television camera and which can suitably set an AF area (AF frame) by selecting the operation methods, according to the photographic state. <P>SOLUTION: The setting operation of the AF area (AF frame) as an object range of AF can be carried out by both an AF operation part 74 constituted by an operation member, such as, track ball, tab, and LCD 40 with a touch panel. On the LCD 40 with the touch panel, a pickup video taken in from a camera body 14 is displayed, and the area of the AF area can be set through touching operations, while the video is viewed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an autofocus system, and more particularly to an autofocus system that can easily set an AF area (AF frame) indicating a target range to be focused by autofocus (AF).

  Conventionally, a contrast method is generally used as an autofocus (AF) method in broadcasting or commercial television cameras. In the contrast method, the contrast of the subject image is detected from the image signal (video signal) of the subject image formed by the imaging lens and captured by the imaging device, and the focus of the photographing lens (focus lens) is set so that the contrast becomes the highest. ) To automatically focus on the best focus state.

  In contrast-based AF, the imaging range (imaging range) of the camera is not an AF target range, but is often limited to a subject within a part of the imaging range. For example, an image signal of a predetermined range (AF area) targeted for AF is extracted from the image signal of the subject image effectively captured by the image sensor, and the contrast of the image is based on the image signal of the extracted range. The focus is controlled so that becomes the highest. As a result, the AF target is limited to a subject within a certain range.

  In this specification, an AF target range (target range for focusing by AF) is referred to as an AF area, and a frame indicating the range of the AF area (an outline of the AF area) is referred to as an AF frame.

  Conventionally, there is known an autofocus system in which an operator such as a cameraman can set (adjust) the range (position, size, shape) of an AF area by manual operation. In such an autofocus system, An AF operation device is installed on a pan stick extending from a pedestal (tripod, pedestaldry) that supports a TV camera, and by operating a joystick (or a trackball) or a volume provided on the AF operation device, An AF area (AF frame) is set (see, for example, Patent Document 1). For example, the size and shape (aspect ratio) of the AF frame can be set by operating a volume, and the position of the AF frame can be set by operating a joystick or a trackball.

Conventionally, there has also been proposed an AF area that can be set by a touch operation on a touch panel installed in a viewfinder (see, for example, Patent Document 2).
JP 2006-251682 A JP 2004-117490 A

  By the way, when setting the AF area by operating the operation member of the AF operation device, the cameraman uses the familiar viewfinder as when operating the focus and zoom with the controller installed on the pan bar. There is an advantage that the setting operation of the AF area can be performed without removing the hand from the pan stick while watching.

  However, the AF area setting operation with the joystick or volume of the AF operation device takes time, and it is difficult to get used to the operation.

  On the other hand, when setting an AF area by operating a touch panel installed in a viewfinder or the like, the AF area setting operation can be performed in the same manner as a range specifying operation on a personal computer. There is an advantage that it is easy.

  However, when operating the touch panel, it is necessary to completely remove the hand from the pan bar, so the pan / tilt operation cannot be performed at the same time, and it is possible to quickly shift to another operation such as a focus operation. There is a disadvantage that it can not.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an autofocus system in which an AF area (AF frame) can be suitably set by an operation method according to a shooting situation.

  In order to achieve the object, the invention according to claim 1 focuses the optical system so that a subject within a predetermined AF area out of the range of the subject imaged by the optical system is focused. In an autofocus system that automatically controls, an AF area operation unit that changes the range of the AF area based on an instruction by manual operation, and changes the range of the AF area based on a touch operation on a screen of a display with a touch panel. And an AF area operation means comprising a first AF area operation means for changing the range of the AF area based on an operation on an operation member other than the display with the touch panel. It is a feature.

  According to a second aspect of the present invention, in the first aspect of the invention, the AF area operating means operated later is validated among the first AF area operating means and the second AF area operating means. It is characterized by that.

  The invention according to claim 3 is characterized in that in the invention according to claim 1 or 2, an image of a subject image formed by the optical system is displayed on the display with a touch panel.

  According to the present invention, when the AF area setting operation is performed, the first AF area operation means and the second AF area operation means having different operability according to the shooting situation and the shooting program can be used properly. The AF area can be easily set.

  According to the present invention, it is possible to suitably set an AF area (AF frame) by selecting an operation method according to a shooting situation.

  The best mode for carrying out an autofocus system according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an external view showing an embodiment of a television camera system to which the present invention is applied. As shown in the figure, the television camera 10 is a camera mainly used for broadcasting or business use, and is composed of a lens device 12 and a camera body 14, and is mounted on a pan head 18 installed on a pedestalry 16. It is supported.

  The pan head 18 has two left and right pan rods 22, 24 extending, and the grip portion 22 A of the right pan rod 22 has a focus demand (focus controller) 26 in which an AF operation device described later is incorporated. Is mounted by a mounting clamp 38, and a zoom demand (zoom controller) 28 is installed in the grip portion of the left pan bar 24.

  In addition, a liquid crystal display (LCD) 40 with a touch panel is installed in the right grip portion by an installation tool 42 as a component of the AF operation device. In the following, the liquid crystal display (LCD) 40 with a touch panel may be simply referred to as an LCD 40.

  The focus demand 26 is provided with a pivotable focus knob 30. When the focus is controlled by manual focus (MF), when the focus knob 30 is pivoted, a focus corresponding to the pivot position is obtained. A focus control signal for instructing movement of the focus (focus lens) with the position as the target position is given from the focus demand 26 to the lens device 12. As a result, the focus lens of the lens device 12 moves to the target position commanded by the focus control signal.

  The zoom demand 28 is provided with a rotatable thumb ring 34. When the thumb ring 34 is rotated in the left-right direction, the zoom (zoom lens) is moved with a zoom speed corresponding to the rotation position as a target speed. A zoom control signal to be commanded is given from the zoom demand 28 to the lens device 12. As a result, the zoom lens of the lens device 12 moves at the target speed commanded by the zoom control signal.

  Although details will be described later, the focus demand 26 is provided with various operation members (operation members for AF) of an AF operation device incorporated in the focus demand 26. The LCD 40 is also used as an AF operation device.

  A viewfinder 36 that is a display device is installed on the camera body 14. Since the viewfinder 36 displays an image of the subject photographed by the camera 10, the cameraman photographs the subject with a desired composition by operating the focus demand 26 and the zoom demand 28 while viewing the image. Can be done. Also, the AF area range, which is the AF target range, can be displayed by, for example, an AF frame indicating its outline, and the AF frame is displayed superimposed on the subject image on the screen of the viewfinder 36. It is like that. Accordingly, when the focus is controlled by AF, it is possible to know which range of the subject within the shooting range is in focus, and an AF operation member (second AF) disposed on the focus demand 26. The AF area is changed to a range (position, size, shape) that matches the desired subject within the shooting range by operating the screen of the LCD 40 (first AF area operation means) with a touch panel (area operation means). Can be done.

  The focus control of MF and AF can be switched by a mode switch or the like provided in the focus demand 26.

  FIG. 2 is a block diagram showing a configuration of an autofocus system applied to the television camera system. Note that FIG. 2 mainly shows components related to AF, and the processing contents of each component will be mainly described.

  As shown in the figure, the autofocus system includes the lens device 12, the camera body 14, the viewfinder 36, and the AF operation device 50 shown in FIG. The AF operation device 50 includes a configuration unit incorporated in the focus demand 26 in FIG. 1 and an LCD 40 with a touch panel in FIG.

  The lens device 12 includes an optical system for forming a subject image and a control system for controlling the focus, zoom, iris, and the like of the optical system. An AF processing unit 62 and a focus driving unit 64 are shown.

  When performing focus control by AF, the CPU 60 focuses on a subject in the AF area designated by the AF operation device 50 as described later, and causes the AF processing unit 62 to set the AF area range (position, size, The focus information on the subject in the AF area is sequentially acquired from the AF processing unit 62 by designating the shape. Then, based on the focus information, the focus drive unit 64 is instructed to drive the focus (focus lens) of the optical system, and the focus is set at a focus position determined to be in focus by the focus information.

  For example, assuming that AF of the contrast method is adopted, the AF processing unit 62 takes in a video signal of a video photographed by the imaging element of the camera body 14 from the camera body 14 and performs AF based on the video signal. A focus evaluation value indicating the contrast level of the video (image) in the area is obtained as focus information.

  As shown in FIG. 3, the AF area 100 is set as a rectangular area within the imaging range 102 of the imaging element of the camera body 14. A frame 104 indicating the outline of the AF area 100 indicates an AF frame.

  Here, in the lens device 12 or the camera main body 14, an AF optical system and an image sensor are provided. For example, a light splitting means such as a half mirror is arranged for an image optical system that forms a subject image on an image pickup surface of an image pickup device (image pickup device) of the camera body 14, and the optical path is branched into two. An optical path of the AF optical system different from the optical path of the image optical system is provided. In the AF optical system, a subject image in a focused state equivalent to the subject image formed by the video optical system is formed, and an AF imaging element for capturing the subject image is disposed. When such an AF optical system and an AF imaging device are provided, the video signal of the video imaged by the AF imaging device is used as the video signal of the video imaged by the imaging device of the camera body 14. You may make it take in in AF process part 62. FIG.

  In contrast AF, a so-called optical path length difference method is known. In the optical path length difference method, for example, the AF optical system is provided as described above, and the optical path is further branched into a plurality (for example, two) in the AF optical system. An imaging surface of the AF imaging element is disposed in each optical path, and each imaging surface is disposed at a position having an optical path length difference. In addition, each imaging surface is arranged at a position where the optical path length becomes longer and a position where the optical path length becomes shorter than the imaging surface of the imaging device for video, for example. Note that the AF imaging element may be one in which a plurality of imaging surfaces with different optical path lengths are formed in one imaging element, or may use a plurality of imaging elements.

  Then, the AF processing unit 62 acquires the video signals of the images captured by the respective imaging surfaces of the AF imaging element, and the AF areas captured by the respective imaging surfaces of the AF imaging element based on the respective video signals. The focus evaluation value of the video within is obtained. Then, by comparing the magnitude relationship of the focus evaluation values with respect to the respective imaging surfaces, the focus state (in-focus, front pin, rear pin) is detected with respect to the subject in the AF area. By providing the CPU 60 with the focus state information thus detected as focus information, the CPU 60 can set the focus to the in-focus position based on the focus information.

  The AF operation device 50 is an operation unit for the cameraman to manually set the position, size, and shape (aspect ratio) of the AF area by manual operation. As shown in FIG. An operation unit 74, a display processing unit 76, a touch panel control unit 78, and the LCD 40 with a touch panel shown in FIG.

  The CPU 70 reads an operation on the operation member of the AF operation unit 74 or a touch operation on the screen of the LCD 40 with a touch panel, and determines the position, size, and shape of the AF area based on those operations. Then, information indicating the range of the determined AF area (AF area information) is transmitted to the CPU 60 of the lens apparatus 12 via SCI (serial communication interface) 72 and 66. In accordance with this AF area information, the AF area set by the CPU 60 as the AF processing unit 62 is set as described above.

  FIG. 4 illustrates an example of the operation member that constitutes the AF operation unit 74. In FIG. 4, the operation member of the AF operation unit 74 is disposed in the main body of the focus demand 26, and a trackball 80, knobs (volumes) 82 and 84, a mode switch 86, an AF start switch 88, and the like are provided. . Reference numeral 30 denotes a focus knob that is rotated when the focus position is designated by the MF.

  The trackball 80 is an operation member for moving the position of the AF area 100 (AF frame 104) shown in FIG. 3 within the imaging range 102, and the AF area 100 in a direction corresponding to the rotation direction of the trackball 80. The position of is to move. Instead of the trackball 80, another input operation device for specifying the position such as a joystick may be provided.

  The knob 82 is an operation member for changing the size of the AF area 100. When the rotation position of the knob 82 is changed, the size of the AF area 100 is adjusted while the center position and the aspect ratio are maintained constant. The size is enlarged or reduced to a size corresponding to the rotational position 82.

  The knob 84 is an operation member for changing the shape (aspect ratio) of the AF area 100. When the rotation position of the knob 84 is changed, the aspect ratio of the AF area 100 is maintained while the center position and the area are maintained constant. Is changed to an aspect ratio corresponding to the rotational position of the knob 84.

  The mode switch 86 is an operation member for selecting a desired mode among the AF off (MF mode), the momentary mode, and the continuous mode, and can be switched at three positions corresponding to each mode. Yes. When AF off is selected, focus control by AF is not executed, and focus control by MF is executed. That is, in this state, the CPU 60 of the lens device 12 moves the focus to a position corresponding to the rotational position of the focus knob 90.

  The momentary mode is a mode in which focus control by AF is executed only while the AF start switch 88 is on, and the continuous mode is a mode in which focus control by AF is always executed.

  Such an AF area setting operation using the trackball 80 and the knobs 82 and 84 of the AF operation unit 74 can be always performed regardless of the mode selected by the mode switch 86. However, a switch for invalidating the setting operation of the AF area (prohibiting the change of the AF area) may be provided to prevent a change due to an erroneous operation, and the change of the AF area is prohibited when the AF is off (MF mode). May be.

  On the other hand, the LCD 40 with a touch panel shown in FIG. 1 and FIG. 2 enables an operator such as a cameraman to perform an AF area setting operation by a touch operation on the screen. Compared with the operation, the AF area setting operation itself can be easily performed.

  On the screen of the LCD 40 with a touch panel, for example, an image currently captured by the television camera 10 and an AF frame indicating the range of the currently set AF area are displayed as in the viewfinder 36. . The video displayed on the LCD 40 is generated by the display processing unit 76, and the video signal of the video captured by the imaging device of the camera main body 14 is captured from the camera main body 14 into the display processing unit 76. Yes. The video output terminal of the camera main body 14 and the video input terminal provided in the focus demand 26 are connected by a cable so that the video signal output from the camera main body 14 is taken into the display processing unit 76.

  The display processing unit 76 is provided with information indicating the currently set AF area range from the CPU 70, and the display processing unit 76 is currently set for the video captured from the camera body 14. The image of the AF frame having a position, size, and shape corresponding to the AF area being superimposed is superimposed, and the video is output to the LCD 40 with a touch panel.

  The touch panel control unit 78 detects a position (coordinates) touched (tapped) on the screen of the LCD 40 with a touch panel, and gives the touch position information to the CPU 70.

  The CPU 70 acquires a touch operation (touch position) on the screen of the LCD 40 performed by the operator based on the touch position information given from the touch panel control unit 78, and the position and size of the AF area based on the touch operation. Determine the shape.

  FIG. 5 is a diagram showing a screen of the LCD 40 with a touch panel. In the figure, when the operator touches point A and then touches point B, the CPU 70 determines a square area having points A and B as diagonal vertices as the AF area 100. The operator touches the position of the diagonal vertex of the quadrangular area to be set as the AF area while watching the captured image displayed on the screen, thereby setting the AF area of the desired size and shape at the position of the desired subject. It can be specified.

  Note that the present invention is not limited to such an operation, and the AF area range may be designated by any method. For example, by touching the point A with the fingertip, touching the screen as it is, and sliding the fingertip and releasing the fingertip from the screen at the point B, it is possible to specify an AF area having the points A and B as diagonal vertices. You may do it.

  Further, when a desired position on the screen is touched twice (double tap) twice, the position of the AF area may be moved so that the position becomes the center position.

  As described above, the AF area can be set by any operation of the AF operation unit 74 and the LCD 40. Which setting of the AF operation unit 74 and the LCD 40 is valid may be specified by, for example, a switch, or may be validated when an operation is performed later.

  In the above-described embodiment, the configuration in which some components (the AF operation unit 74 and the like) of the AF operation device 50 are incorporated in the focus demand 26 has been described. Alternatively, it may be configured as a controller independent of other controllers. Further, the operation member for performing the AF area setting operation may have any configuration.

  Moreover, in the said embodiment, LCD40 with a touch panel is installed in the bread stick 22 (refer FIG. 1), However, LCD40 may be installed in any position. Alternatively, a touch panel may be attached to the viewfinder 36 instead of the LCD 40 with a touch panel (the viewfinder 36 is a display with a touch panel), and the AF area setting operation may be performed by a touch operation on the screen of the viewfinder 36.

  In the above embodiment, the image captured by the camera 10 is displayed on the LCD 40. However, when the lens device 12 includes the AF image sensor, the image captured by the AF image sensor. May be acquired from the lens device 12 and displayed on the LCD 40. Further, for example, the position (coordinates) on the screen of the viewfinder 36 and the position (coordinates) on the screen of the LCD 40 are made to correspond to each other while viewing the captured image displayed on the viewfinder 36 and the AF area (AF frame). If the AF area setting operation is performed by operating the screen of the LCD 40, the captured image may not be displayed on the LCD 40.

  In the above embodiment, the position, size, and shape of the AF area can be changed by the AF operation unit 74 or the LCD 40. However, all elements of the position, size, and shape are not necessarily changed as the range of the AF area. It doesn't have to be made possible. For example, only the position change may be possible.

FIG. 1 is an external view showing an embodiment of a television camera system to which the present invention is applied. FIG. 2 is a block diagram showing the configuration of the autofocus system according to the present invention. FIG. 3 is an explanatory diagram showing an AF area (AF frame). FIG. 4 is an external view showing the configuration of the operation unit of the AF operation device. FIG. 5 is an explanatory diagram used for explaining the AF area setting operation by the LCD with a touch panel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Television camera, 12 ... Lens apparatus, 14 ... Camera body, 16 ... Pedestardry, 18 ... Pan head, 22, 24 ... Pan stick, 26 ... Focus demand, 28 ... Zoom demand, 30 ... Focus knob, 36 ... View Finder, 40 ... Liquid crystal display with touch panel, 50 ... AF operation device, 60, 70 ... CPU, 62 ... AF processing unit, 64 ... Focus drive unit, 74 ... AF operation unit, 76 ... Display operation unit, 78 ... Touch panel control unit , 80 ... track ball, 82, 84 ... knob, 100 ... AF area, 104 ... AF frame

Claims (3)

In the autofocus system that automatically controls the focus of the optical system so that the subject within the range of a predetermined AF area is in focus within the range of the subject imaged by the optical system,
AF area operation means for changing the range of the AF area based on an instruction by manual operation, and first AF area operation means for changing the range of the AF area based on a touch operation on the screen of a display with a touch panel. An autofocus system comprising an AF area operation means comprising a second AF area operation means for changing the range of the AF area based on an operation on an operation member other than the display with a touch panel.   2. The autofocus system according to claim 1, wherein the AF area operation unit operated later is validated among the first AF area operation unit and the second AF area operation unit. 3.   3. The autofocus system according to claim 1, wherein an image of a subject image formed by the optical system is displayed on the display with a touch panel.

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