JP2006139115A - Autofocus system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an autofocus system capable of adjusting the position, the size and the shape of an AF area being an AF object range, wherein the space saving of an operation member is attained by using one operation member to adjust both the size and the shape of the AF area. <P>SOLUTION: A joy stick 62 being an AF area operation part, an AF frame size/shape adjusting knob 64 and an AF frame adjusting and selecting switch 66 are arranged on a focus demand 26 for autofocus operation of a television camera. The AF frame size/shape adjusting knob 64 is used to adjust both the size and the shape of the AF frame (AF area), and which object between them is changed is selected by the AF frame adjusting and selecting switch 66. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an autofocus system, and more particularly to an autofocus system that can change the size, shape, and the like of an AF area that is a target range of autofocus (AF) in an imaging range of a camera.

  In an imaging system that converts an image of a subject into an electrical signal (image signal) using a photographing element (CCD or the like) like a television camera, a contrast method is generally employed as an autofocus (hereinafter referred to as AF) method. . The contrast method is best by detecting the contrast of the subject image from the image signal (video signal) of the subject image captured by the image sensor and controlling the focus (focus lens) of the photographing lens so that the contrast becomes the highest. This is a method of automatically focusing in the focused state.

  In contrast-based AF, an object that effectively captures an image formed by an optical system, i.e., an entire subject image range, is not an AF target range. In many cases, only a subject in a certain range is targeted. For example, out of the image signals of the subject image effectively captured by the image sensor, an image signal in a predetermined range that is a target of AF is extracted, and the contrast of the image becomes the highest based on the image signal in the extracted range. So that the focus is controlled. As a result, the AF target is limited to a subject within a certain range. In this specification, an AF target range 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.

When a single AF area is fixed at a predetermined position within the imaging range, a rectangular AF area is generally set at the center of the imaging range. There is also known one in which the area can be changed to a desired position (for example, see Patent Document 1). Conventionally, as a method for specifying the position of the AF area, for example, a method in which a predetermined direction indicating member is operated to move the AF area up and down, left and right with respect to the imaging range and move the AF area to a target position is used. ing.
JP 2003-224759 A

  By the way, not only the position of the AF area but also the size and shape of the AF area can be changed, the size and shape of the AF area can be adjusted according to the size and shape within the imaging range of the subject to be focused. It is effective because it can. However, when the size and shape can be changed in addition to the position of the AF area, it is necessary to provide an operation member for that purpose. In particular, when the size and shape of the AF area can be changed in multiple steps (continuously), the operation position is not continuous, for example, a rotary knob but a continuous operation position. It is necessary to provide an operation member that can be changed at multiple positions and a position sensor (volume or the like) that detects the operation position based on a voltage level or the like. If such operation members and position sensors are separately provided for adjusting the size and shape of the AF area, a space is required for such operation members and position sensors (lens body and controller). Etc.) becomes difficult to reduce in size.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an autofocus system that can reduce the arrangement space of the operation member related to the operation of the AF area.

  In order to achieve the above object, the autofocus system according to claim 1 controls the focus of the photographic lens with the subject in the AF area within the imaging range of the camera as the target of autofocus, and the range of the AF area. Auto focus means for automatically focusing on the subject, size / shape adjustment operation member used to change the size and shape of the AF area, and operation of the size / shape adjustment operation member Selecting means for selecting which of the size and shape of the AF area to be changed, and AF for changing the object selected by the selection means based on the operation of the size / shape adjusting operation member And an area change processing means.

  According to the present invention, since one operation member can be selected as an operation member for changing the size and shape of the AF area by a selection unit such as a switch, A single size / shape adjusting operation member can be used together without separately providing an operation member for adjusting the size and shape of the area. Therefore, it is possible to reduce the arrangement space of the operation member for adjusting the size and shape of the AF area, and it is possible to reduce the size of the AF area operation unit where the operation member is arranged.

  In addition, the size and shape of the AF area are rarely required to be adjusted at the time of shooting, and one of the priority objects (the object that is frequently changed) can be changed by the size / shape adjusting operation member. If selected by the selection means, there is almost no operational problem with respect to the inability to change those objects at the same time.

  According to a second aspect of the present invention, in the invention of the first aspect, the size / shape adjusting operation member can be set at a continuous operation position, and the AF area change processing means is The object selected by the selection means is changed in a continuous state in accordance with a change in the continuous operation position of the size / shape adjusting operation member. In order to change the size and shape of the AF area in a continuous state, it is necessary that the size / shape adjusting operation member can be set to a continuous operation position as in the present invention. In such a case, if such an operation member is provided separately for adjusting the size and shape of the AF area, a large arrangement space is required, so that one size / shape adjusting operation member is also used. The effect is great.

  According to a third aspect of the present invention, there is provided the autofocus system according to the first or second aspect, further comprising a position changing operation member for changing a position of the AF area, wherein the AF area changing processing means The position of the AF area is changed based on the operation of the changing operation member. The present invention is an aspect in which an operation member for changing the position of the AF area is separately provided.

  According to a fourth aspect of the present invention, in the invention according to the first, second, or third aspect, the size / shape adjusting operation member includes an operation member that operates focus or zoom of the camera. It is characterized by being arranged in a drive unit installed on the side of the lens barrel of the controller or the taking lens. That is, when the AF area operation unit for arranging the size / shape adjusting operation member is arranged in the focus or zoom controller or in the drive unit, the controller or the drive unit can be made small. .

  According to the autofocus system of the present invention, it is possible to reduce the arrangement space of the operation member related to the operation of the AF area.

  Hereinafter, preferred embodiments of an autofocus system according to the present invention will be described in detail 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 includes a lens device 12 and a camera body 14, and is supported by a camera platform 18 installed on a pedestal 16.

  The left and right operation rods 22, 24 are extended on the pan head 18, and a focus demand (focus controller) 26 is installed on the grip portion 22 A of the right operation rod 22 by a mounting clamp 38. A zoom demand (zoom controller) 28 is installed in the grip portion of the operation rod 24. The focus demand 26 and the zoom demand 28 are connected to a predetermined connector of the lens device 12 via a cable.

  The focus demand 26 is provided with a pivotable focus knob 30. When the focus knob 30 is pivoted, the focus (focus lens) is moved with the focus position corresponding to the pivot position as a target position. A focus control signal to be commanded 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.

  As will be described in detail later, the focus demand 26 includes an AF start switch that instructs the start of autofocus (AF), a joystick that operates the position, size, and shape of the AF area that is the target area of AF. An AF area operation unit including an operation member is integrally provided.

  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.

  A viewfinder 36 that is a display device is installed on the camera body 14. Since the viewfinder 36 displays the 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 do. In addition, the AF area range that is the target range of autofocus (AF) can be displayed by, for example, an AF frame indicating its outline, and the AF frame is superimposed on the subject image on the screen of the viewfinder 36. Is displayed. Therefore, when AF is executed, it is possible to know which subject within the shooting range (imaging range) is in focus, and to operate the AF area operation unit disposed on the focus demand 26. Thus, the AF area can be adjusted to a desired range.

  FIG. 2 is a block diagram showing a configuration of an autofocus system applied to the television camera system. The autofocus system shown in FIG. 1 includes the lens device 12, the camera body 14, the viewfinder 36, and an AF area operation unit 54 that is integrally disposed on the focus demand 26.

  The lens device 12 includes a CPU 50 and an AF processing unit 52. Further, the lens device 12 includes an optical system (photographing lens) (not shown) that forms an image of subject light on the imaging surface of the imaging element of the camera body 14, and the optical system includes an optical axis such as a focus lens and a zoom lens. A movable lens group, a fixed lens group, and the like are arranged in the direction. Each movable lens group is driven by a motor (not shown) in accordance with a control signal from the CPU 50, and the CPU 50 controls the position and speed of the focus lens, zoom lens, and the like.

  The focus lens control (focus control) includes manual focus (MF) and autofocus (AF). During MF, a focus control signal output from the focus demand 26 shown in FIG. 1 according to the operation of the focus knob 30. Is acquired by the CPU 50, and the focus lens is controlled so as to be the target position commanded by the focus control signal.

  On the other hand, during AF, focus information (focus evaluation value) detected by the AF processing unit 52 is given to the CPU 50, and the focus lens is controlled based on the focus information. The camera body 14 generates a video signal of a video imaged by the imaging device, and the video signal (luminance signal) is supplied from the camera body 14 to the AF processing unit 52. The AF processing unit 52 performs processing for detecting the contrast of the subject image based on the video signal.

  Here, if the subject or the range of the subject image that is effectively imaged by the imaging element of the camera body 12 is referred to as an imaging range, an AF area that is an AF target range with respect to the imaging range 90 as shown in FIG. For example, 92 is set within the range of the rectangular AF frame 94. Note that the position, size, and shape of the AF area 92 (AF frame 94) within the imaging range 90 are changed according to AF area information provided from the AF area operation unit 54 as described later. 3 corresponds to the shooting range of the television camera 10 and the subject image (video) captured by the imaging element of the camera body 14 is reproduced and displayed on the screen of the viewfinder 36 or the like. Corresponds to the image screen range.

  In FIG. 2, the video signal given from the camera body 14 to the AF processing unit 52 includes video information of the entire imaging range, and the AF processing unit 52 extracts only the video signal within the range of the AF area from the video signal. Then, the high frequency components of the video signal are integrated one field (one screen) at a time. Thus, values indicating the level of contrast of the subject image in the AF area are sequentially obtained. The value (integrated value) is referred to as a focus evaluation value in this specification.

  The CPU 50 sequentially acquires the focus evaluation value from the AF processing unit 52 as focus information, and moves the focus lens to a position where the focus evaluation value is maximized (maximum). Thus, the subject in the AF area is automatically focused.

  The video signal obtained by the image sensor of the camera body 14 is given from the camera body 14 to the viewfinder 36, and the currently captured image is displayed on the screen of the viewfinder 36. In addition, the CPU 50 of the lens device 12 is given AF area information (information on the position, size, and shape of the AF area) indicating the range of the AF area currently set as the AF target range to the camera body 14. It has become. Based on the AF area information, the camera body 14 combines the signal of the AF frame (the outline of the AF area) indicating the current AF area range with the video signal output to the viewfinder 36, as shown in FIG. In addition, an image of the AF frame 94 indicating the current range of the AF area 92 is displayed on the screen of the viewfinder 36 together with the image of the imaging range 90. This allows the photographer to recognize the current AF area range.

  The AF area operation unit 54 is an operation unit for setting and changing the position, size, and shape of the AF area, and is configured integrally with the focus demand 26. FIG. 4 is a plan view showing the appearance of the focus demand 26. As shown in the figure, the focus demand 26 includes a cylindrical main body portion 80 in which various circuits are built, and the main body portion 80 is operated to rotate during MF and designates a target movement position of the focus lens. A focus knob 30 is rotatably provided. An AF start switch 82 is disposed on the peripheral surface of the main body 80, and a joystick 62, an AF frame size / shape adjustment knob 64, and an AF frame adjustment selection switch 66 are disposed as operation members of the AF area operation unit 54. Yes.

  The AF start switch 82 is a switch for starting AF. When the AF start switch 82 is turned on during MF, the signal is given to the CPU 50 of the lens device 12 so that the CPU 50 starts AF processing. It has become. The switching from AF to MF is performed by turning the focus knob 30.

  On the other hand, a joystick 62 arranged as an operation member of the AF area operation unit 54 is a direction indicating member for adjusting the position of the AF area (AF frame). Is moved vertically and horizontally on the screen (on the imaging range).

  The AF frame size / shape adjustment knob 64 is an operation member that is also used to adjust the size and shape of the AF area (AF frame). When the AF frame size / shape adjustment knob 64 is rotated, the center of the AF area is fixed as described later. The size or shape of the AF area is changed according to the state.

  The AF frame adjustment selection switch 66 uses the AF frame size / shape adjustment knob 64 as an operation member for adjusting the size of the AF area (AF frame) or as an operation member for changing the shape of the AF frame. This is a two-position switching slide switch for selecting whether to use. When the AF frame adjustment selection switch 66 is set to the upper side in the drawing, the size of the AF area is adjusted by operating the AF frame size / shape adjustment knob 64. If the AF frame adjustment selection switch 66 is set to the lower side in the figure, the shape of the AF area can be adjusted.

  The main body 80 of the focus demand 26 is equipped with a CPU that performs each process based on the operation of each operation member. The CPU performs AF based on the operation based on the operation of the focus knob 30 and the AF start switch 82. Processing as the area operation unit 54 is executed. In FIG. 2, the CPU of the focus demand 26 is shown as the CPU 60 of the AF area operation unit 54.

  In FIG. 2, the CPU 60 transmits AF area information indicating the position, size, and shape of the AF area (AF frame) to the CPU 50 of the lens apparatus 12, and the AF of the lens apparatus 12 is in accordance with the AF area information. The position, size, and shape of the AF area in the processing unit 52 and the viewfinder 36 are set. The CPU 60 determines the position, size, and shape of the AF area designated by the AF area information based on the operation of the joystick 62 and the AF frame size / shape adjustment knob 64 and the selected position of the AF frame adjustment selection switch 66. By changing, the position, size, and shape of the AF area in the AF processing unit 52 and the viewfinder 36 are changed as follows.

  As shown in FIG. 2, a position sensor 68 is attached to the joystick 62, and the operation of the joystick 62 is detected by the position sensor 68. For example, a signal (voltage value) indicating the angle at which the joystick 62 is tilted in the vertical direction and the angle at which the joystick 62 is tilted in the horizontal direction by the tilting operation in the vertical and horizontal directions with reference to the neutral position where the joystick 62 returns in the non-operating state is the position sensor 68 And the signal is given to the CPU 60.

  The CPU 60 reads the operation direction of the joystick 62 based on the signal from the position sensor 68. Then, based on the operation direction, the position of the AF area 92 (AF frame 94) in the AF processing unit 52 of the lens device 12 and the viewfinder 36 is moved up, down, left, and right in the imaging range 90 as shown in FIG.

  For example, when the joystick 62 is operated to the left as viewed from the position facing the joystick 62, the position of the AF area 92 (AF frame 94) in the imaging range 90 shown in FIG. Move. Similarly, when the joystick 62 is operated in the right direction, the upward direction, and the downward direction, the position of the AF area 92 is the same as the operation direction, the right direction indicated by the arrow B, the upward direction indicated by the arrow C, and the arrow D. A predetermined amount is moved in each of the downward directions shown.

  For example, the CPU 60 moves the position of the AF area 92 by a predetermined amount in the same direction as the operation direction every time the joystick 62 has been operated in a certain direction for a certain period of time. The position is continuously changed. Note that the movement speed of the AF area 92 may be increased in accordance with the amount of operation (tilt angle) of the joystick 62.

  As shown in FIG. 2, a position sensor 70 is attached to the AF frame size / shape adjustment knob 64 so that the operation of the AF frame size / shape adjustment knob 64 is detected by the position sensor 70. It has become. For example, a signal having a value corresponding to the rotation position at which the AF frame size / shape adjustment knob 64 is set by a rotation operation with a predetermined rotation position as a reference is output from the position sensor 70 and provided to the CPU 60.

  The CPU 60 reads the rotational position of the AF frame size / shape adjustment knob 64 based on the signal from the position sensor 70. Further, the CPU 60 detects which position of the two selectable positions the AF frame adjustment selection switch 66 is set as shown in FIG.

  When the AF frame adjustment selection switch 66 is set to a position (lower position in FIG. 4) for selecting size adjustment (size adjustment), the CPU 60 rotates the AF frame size / shape adjustment knob 64. Based on the position, the size of the AF area 92 (AF frame 94) in the AF processing unit 52 and the viewfinder 36 of the lens apparatus 12 is enlarged or reduced as shown in FIG.

  For example, when the value indicating the rotational position of the AF frame size / shape adjustment knob 64 is operated in a direction in which the value is larger than the current value, the AF frame 94 indicated by a solid line corresponding to the current value as shown in FIG. Like the AF frame 94 shown in FIG. 1, the center position and the aspect ratio of the AF area 92 are enlarged while being maintained. When the value indicating the rotational position of the AF frame size / shape adjusting knob 64 is operated in a direction to be smaller than the current value, the AF frame 94 is reduced while maintaining the center position and the aspect ratio. The rotational position of the AF frame size / shape adjusting knob 64 is indicated by a continuous value, and the size of the AF frame 94 is also continuously changed by increasing or decreasing the value.

  On the other hand, when the AF frame adjustment selection switch 66 is set to a position for selecting shape adjustment (upper position in FIG. 4), the CPU 60 selects the position of FIG. 7 based on the rotational position of the AF frame size / shape adjustment knob 64. In this manner, the shape of the AF area 92 (AF frame 94) in the AF processing unit 52 and the viewfinder 36 of the lens apparatus 12 is changed.

  For example, when the value indicating the rotational position of the AF frame size / shape adjustment knob 64 is operated in a direction larger than the current value, the center position and area of the AF area 92 are maintained, as shown in FIG. The AF frame 94 indicated by the solid line corresponding to the current value is increased in the vertical width (the width in the Y direction) as the AF frame 94 indicated by the dotted lines ahead of the arrows A and B (the horizontal width is reduced). To) the shape of the AF area 92 is changed. When the value indicating the rotational position of the AF frame size / shape adjustment knob 64 is operated in a direction smaller than the current value, the solid line corresponding to the current value is maintained while maintaining the center position and area of the AF area 92. The shape of the AF frame 94 indicated by is changed so that the horizontal width (width in the X direction) of the AF area 92 is increased (the vertical width is reduced) like the AF frame 94 indicated by the dotted line ahead of the arrow C. . The shape of the AF frame 94 is also continuously changed by the increase or decrease of the AF frame size / shape adjustment knob 64 continuously.

  Here, when the absolute position is detected by the position sensor 70 as the detection of the rotational position of the AF frame size / shape adjusting knob 64, the size or shape of the AF area 92 corresponding to the absolute position is detected. Shall be set. In this case, when the size adjustment and shape adjustment are switched by the AF frame adjustment selection switch 66, the size or shape of the AF area 92 changes according to the rotational position of the AF frame size / shape adjustment knob 64 at that time. Even in such a case, the AF area 92 can be adjusted to a desired size and shape. However, when the size adjustment and the shape adjustment are switched by the AF frame adjustment selection switch 66, the AF area 92 can be adjusted. The size and shape can be prevented from changing. For example, the rotation position of the AF frame size / shape adjustment knob 64 when the size adjustment and the shape adjustment are switched is set as a reference position, and the amount of change in the rotation position of the AF frame size / shape adjustment knob 64 with respect to the reference position is detected. Then, the size or shape of the AF area 92 is changed by the amount of change. According to this, if the rotational position of the AF frame size / shape adjustment knob 64 is not changed after switching between the size adjustment and the shape adjustment, the size and shape of the AF area 92 do not change, and after the switching, The size or shape of the AF frame can be changed by the amount of operation of the AF frame size / shape adjustment knob 64 (change amount of the rotational position).

  According to the processing of the AF area operation unit 54 described above, the AF area 92 (AF frame) can be adjusted to a desired position, size, and shape, and the AF processing unit 52 focuses on the subject in the AF area 92. And the range of the AF area 92 is displayed on the viewfinder 36. In addition, since one AF frame size / shape adjustment knob 64 is also used as an operation member for adjusting the size and shape of the AF area 92, the arrangement space for the operation member relating to the operation of the AF area can be reduced.

  In the above embodiment, the case where the AF area operation unit 54 is disposed on the focus demand 26 has been described. However, the AF area operation unit 54 may be configured by a dedicated controller or disposed on the zoom demand 28. May be. Moreover, it can also arrange | position in desired positions, such as the lens apparatus 12 and the camera main body 14.

  Further, when the lens device 12 is a portable so-called ENG lens as shown in FIG. 8, the lens barrel 100 is provided with operation rings 102, 104, and 106 for adjusting the focus, zoom, and iris. A drive unit 108 for driving the operation rings 102, 104, 106 by a motor is attached to the side of the lens barrel 100. Various operation members such as a zoom seesaw switch 110 for zoom operation and a VTR switch 112 are disposed in the case of the drive unit 108, for example. The AF area operation unit 54 in the above embodiment may be disposed in the drive unit 108. As shown in the figure, the joystick 62 and the size / shape adjustment knob similar to those in FIG. 64, an AF frame adjustment selection switch 66 may be provided.

  Further, in the above embodiment, the case where the joystick 62 is used as the direction indicating member for instructing the moving direction of the AF area has been described. Any operation member that can instruct the direction, such as four arranged switch members, is applicable.

  In the above embodiment, the size and shape of the AF area can be adjusted by using one operating member. However, the position, size, and shape of the AF area can be adjusted by using one operating member. It is also possible to perform the same. For example, the joystick 62 shown in FIG. 4 and the like is provided, and a selection switch for selecting a desired adjustment from among the AF area position adjustment, size adjustment, and shape adjustment is provided, and the adjustment selected by the selection switch is performed with the joystick. 62 can be performed.

  The present invention can also be applied to AF other than the contrast method as in the above embodiment.

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. FIG. 3 is a diagram illustrating an AF area range in the imaging range. FIG. 4 is a plan view showing a focus demand provided with an AF area operation unit as seen from the front when viewed from the cameraman's standing position. FIG. 5 is an explanatory diagram showing a state in which the position of the AF area is moved up, down, left, and right in the imaging range. FIG. 6 is an explanatory diagram showing a state when the size of the AF area is enlarged / reduced in the imaging range. FIG. 7 is an explanatory diagram showing a state when the shape of the AF area is changed in the imaging range. FIG. 8 is an external view showing a case where the AF area operation unit is arranged in the drive unit of the ENG lens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Television camera, 12 ... Lens apparatus, 14 ... Camera body, 26 ... Focus demand, 28 ... Zoom demand, 30 ... Focus knob, 36 ... Viewfinder, 50, 60 ... CPU, 52 ... AF processing part, 54 ... AF Area operation unit 62 ... Joystick 64 ... Size / shape adjustment knob 66 ... AF frame adjustment selection switch 68, 70 ... Position sensor 72 ... AF start switch 82 ... AF start switch 90 ... Imaging range 92 ... AF area, 94 ... AF frame

Claims (4)

Autofocus means for controlling the focus of the taking lens with the subject in the AF area of the imaging range of the camera as the target of autofocus, and automatically focusing on the subject in the AF area;
A size / shape adjusting operation member used to change the size and shape of the AF area;
Selecting means for selecting which one of the size and shape of the AF area to be changed by operating the size / shape adjusting operation member;
An AF area change processing means for changing an object selected by the selection means based on an operation of the size / shape adjusting operation member;
An autofocus system characterized by comprising   The size / shape adjusting operation member can be set at a continuous operation position, and the AF area change processing means is accompanied by a change in the continuous operation position of the size / shape adjustment operation member. The autofocus system according to claim 1, wherein the object selected by the selection means is shifted in a continuous state.   A position adjustment operation member for changing the position of the AF area is provided, and the AF area change processing means changes the position of the AF area based on an operation of the position adjustment operation member. The autofocus system according to claim 1 or 2.   The size / shape adjusting operation member is disposed in a controller provided with an operation member for operating focus or zoom of the camera or a drive unit installed on a lens barrel side portion of the photographing lens. 4. The autofocus system according to claim 1, 2, or 3.

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