JP2004117490A - Autofocus system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an autofocus system capable of easily and rapidly setting and changing the position and the size of a focus area in accordance with the position and the size of a main subject on an image plane by detecting the operation of a television camera or the like on a monitor screen by a touch panel and changing the position and the size of the object frame (focus area) of autofocus by such operation. <P>SOLUTION: The touch panel 18 is provided on a monitor 16 for displaying a photographic image according to a video signal from a camera main body 10. When a photographer touches two points diagonally located in the focus area to be set on the image plane of the monitor 16, the focus area is given from a focus area setting part 20 to an AF circuit 14, and processing for autofocus control with the focus area as an object is performed by the AF circuit 14. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an autofocus system, and more particularly, to an autofocus system that performs contrast type autofocus control.
[0002]
[Prior art]
2. Description of the Related Art In a camera for photographing a moving image, a contrast method is generally adopted as an autofocus method. In the contrast method, a focus evaluation value is generated by integrating high frequency components of a video signal in a certain target frame (focus area) of a video signal obtained from an image sensor, and the focus evaluation value is maximum (maximum). The focus adjustment is automatically performed so that Thereby, the best focus (focusing) that maximizes the sharpness (contrast) of the image captured by the image sensor is obtained.
[0003]
[Problems to be solved by the invention]
Incidentally, the focus area is generally fixed at the center of the screen, but the main subject to be focused is not always located at the center of the screen, and its size is not constant. Therefore, it is convenient if the focus area can be easily and quickly set and changed to a position and a size corresponding to the main subject.
[0004]
The present invention has been made in view of such circumstances, and an autofocus system that can easily and quickly set and change the position and size of a focus area according to the position and size of a main subject on a screen. The purpose is to provide.
[0005]
[Means for Solving the Problems]
In order to achieve the object, among images captured by a camera, an image captured by the camera in an autofocus system that performs autofocus control of the camera with respect to an image within a predetermined target frame A display unit that displays an image, an operation detection unit that detects an operation performed on the screen of the display unit by a touch panel provided on a front surface of the display unit, and a desired operation based on the operation detected by the operation detection unit. And a target frame setting means for setting a rectangular frame having a position and a size as the target frame.
[0006]
According to a second aspect of the present invention, in the first aspect of the present invention, the target frame setting unit sets the rectangular frame having two points designated by the operation detecting unit as diagonal positions. It is characterized in that it is set as a target frame.
[0007]
According to a third aspect of the present invention, in the first or second aspect of the invention, the autofocus control controls a focus of the camera so that a contrast of an image in the target frame is increased. In this way, the focus is automatically adjusted.
[0008]
According to a fourth aspect of the present invention, in the first aspect of the present invention, the camera is a video camera.
[0009]
According to the present invention, the position and the size of the target frame (focus area) of the autofocus can be changed by the operation on the display screen of the image captured by the camera. Accordingly, the position and size of the focus area can be set and changed easily and quickly.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of an autofocus system according to the present invention will be described in detail with reference to the accompanying drawings.
[0011]
FIG. 1 is a block diagram showing a configuration of an autofocus system according to the present invention applied to a television camera system. In FIG. 1, the television camera includes a camera body 10 and a lens device 12. The camera body 10 has a required signal processing circuit that generates and outputs a video signal of an image sensor or a subject captured by the image sensor as a video signal. And so on. The lens device 12 includes a photographing lens that forms an image of subject light from the subject, a drive circuit that drives a focus (focus lens), a zoom (zoom lens), and the like of the photographing lens.
[0012]
On the other hand, the video signal generated by the camera body 10 is output to an AF circuit 14 that executes an autofocus control process, and is also output to a monitor 16 (viewfinder) for a photographer to check a captured video in real time. It is supposed to be. The AF circuit 14 may be built in the lens device 12 or the camera body 10. Further, the monitor 16 is not limited to a use for a photographer to confirm a photographed image in real time.
[0013]
The AF circuit 14 sets an image (video signal) in a focus area (target frame) set as described later as a target image based on the video signal obtained from the camera body 10, and contrasts the target image (image contrast). (Sharpness) is evaluated. If the value for evaluating the contrast is referred to as a focus evaluation value, the focus evaluation value increases as the contrast increases. Then, a focus drive signal is commanded to increase the focus evaluation value by a focus command signal to a focus drive circuit built in the lens device 12, and the focus is set so that the focus evaluation value becomes a maximum value. Thereby, the subject in the focus area is focused.
[0014]
On the other hand, the focus area can be set and changed to a desired position and size by a photographer or the like by touch input on the screen of the monitor 16 by the following configuration. In the present embodiment, the focus area is limited to a rectangular shape (rectangle) because of the easiness of the operation of designating the focus area.
[0015]
As shown in the figure, a touch panel 18 is arranged on the front surface of the screen of the monitor 16. When a photographer or the like touches the screen of the monitor 16 with a fingertip or the like, the touched position (coordinate) is changed to a focus area setting unit 20. Is detected by The focus area setting unit 20 monitors an operation of a touch input on the touch panel 18 and transmits coordinates specifying a focus area to the AF circuit 14 based on the operation.
[0016]
As shown in FIG. 2, the touch panel 18 arranged in accordance with the screen of the monitor 16 is subdivided into a plurality of regions, and each region has, for example, horizontal coordinates 1 to 8 and vertical coordinates A to H. It is represented by a combination. Then, the coordinates of the area including the touched portion are detected by the CPU 22 of the focus area setting unit 20. Although the processing of the CPU 22 will be described later, for example, as shown in FIG. 3, when the photographer or the like touches (1) and (2) on the screen in order, the (1) and (2) areas are The CPU 22 detects the coordinates of the areas (1) and (2) and sets the coordinates of the areas (1) and (2) to the focus area FA. Are transmitted to the AF circuit 14 in FIG.
[0017]
The AF circuit 14 uses the coordinates (1) and (2) for specifying the focus area FA given from the focus area setting unit 20 to set the image (video signal) in the focus area FA as a target image as described above. Performs auto focus control processing. Note that the AF circuit 14 keeps the previously set focus area valid until the focus area setting unit 20 gives new coordinates of the focus area. The initial focus area is, for example, a predetermined standard focus area.
[0018]
FIG. 4 is a flowchart showing a processing procedure of the CPU 22 corresponding to the focus area designating operation shown in FIG. First, the CPU 22 determines whether a touch input has been made on the screen of the monitor 16 (step S10). When the determination is NO, this determination is repeated, and when the determination is YES, the coordinates (1) are stored (step S12). Subsequently, the CPU 22 determines whether a touch input has been made on the screen of the monitor 16 (step S14). When the determination is NO, this determination is repeated, and when the determination is YES, the coordinates (2) are stored (step S16). Then, the coordinates (1) and (2) are transmitted to the AF circuit 14 as coordinates for specifying the focus area (step S18).
[0019]
As described above, in the above-described embodiment, a case has been described in which the focus area designating operation is performed by sequentially designating two diagonal points of the focus area as shown in FIG. Is not limited to this.
[0020]
For example, as shown in FIG. 5, (1) on the screen of the monitor 16 is touched with a fingertip or the like, and the fingertip is slid while keeping touching the screen, and the finger is released from the screen with (2). Thus, the focus area FA may be set so that the coordinate (1) touched first and the coordinate (2) released first are diagonal.
[0021]
The processing procedure of the CPU 22 in this case is shown in the flowchart of FIG. First, the CPU 22 determines whether a touch input has been made on the screen of the monitor 16 (step S30). If the determination is NO, this determination is repeated, and if the determination is YES, the coordinates are stored (step S32). Subsequently, the CPU 22 determines whether or not a touch input has been made on the screen of the monitor 16, that is, whether or not a touch has been made on the continued screen (step S34). If the determination is YES, the coordinates (2) are read (step S36). Subsequently, it is determined whether or not the read coordinates have changed from the previously read coordinates (step S38). If the determination is YES, the coordinates read in step S36 are stored (step S40), and the process returns to step S34. On the other hand, if NO is determined in the step S38, the process returns to the step S34 without performing the process of the step S40.
[0022]
If NO in step S34, that is, if it is determined that a touch input has not been made, the CPU 22 obtains the coordinates (1) of the first touch input and the coordinates (2) of the first release of the touch input (step S42). . That is, the coordinates stored in step S32 are coordinates (1), and the coordinates stored last in step S40 are coordinates (2). Then, the coordinates (1) and (2) are transmitted to the AF circuit 14 as coordinates for specifying the focus area (step S44).
[0023]
In addition to the focus area designation operation shown in FIGS. 3 and 5, for example, as shown in FIG. 7, if the user touches the screen of the monitor 16 from (1) and slides it so as to draw a closed curve, the touch is performed. The minimum rectangular range FA including the entire area may be set as the focus area.
[0024]
In the above embodiment, the position and size of the focus area are specified at the same time. However, the present invention is not limited to this, and only the position or the size may be set. For example, if no special designation is made, the size of the focus area is fixed, and a focus area centered on the position touched on the screen can be set. You may make it changeable by the touch input on a screen.
[0025]
Further, the present invention can be applied not only to a camera for capturing a moving image but also to a camera for capturing a still image.
[0026]
【The invention's effect】
As described above, according to the autofocus system according to the present invention, the position and size of the target frame (focus area) of the autofocus can be changed by operating the image captured by the camera on the display screen. The position and size of the focus area can be set and changed easily and quickly according to the position and size of the main subject on the screen.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an autofocus system according to the present invention applied to a television camera system.
FIG. 2 is a diagram showing a configuration of a touch panel and a focus area setting unit 20;
FIG. 3 is an explanatory diagram illustrating an operation of designating a focus area;
FIG. 4 is a flowchart illustrating a processing procedure of a CPU of a focus area setting unit corresponding to the designation operation in FIG. 3;
FIG. 5 is an explanatory diagram showing another method of designating a focus area.
FIG. 6 is a flowchart illustrating a processing procedure of a CPU of a focus area setting unit corresponding to the designation operation in FIG. 5;
FIG. 7 is an explanatory diagram showing another method of specifying a focus area.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Camera main body, 12 ... Lens device, 14 ... AF circuit, 16 ... Monitor, 18 ... Touch panel, 20 ... Focus area setting part, 22 ... CPU, 24 ... Serial communication circuit

Claims (4)

In an autofocus system that performs autofocus control of the camera on an image in a predetermined target frame, among images captured by a camera,
A display unit that displays an image captured by the camera,
Operation detecting means for detecting an operation performed on a screen of the display unit by a touch panel provided on a front surface of the display unit,
An autofocus system comprising: target frame setting means for setting a rectangular frame having a desired position and size as the target frame based on an operation detected by the operation detection means. 2. The autofocus system according to claim 1, wherein the target frame setting unit sets a rectangular frame having two points designated by the operation detection unit as diagonal positions as the target frame. 3. The autofocus system according to claim 1, wherein the autofocus control automatically performs focusing by controlling a focus of the camera so that a contrast of an image in the target frame is increased. 4. The autofocus system according to claim 1, wherein the camera is a camera for shooting a moving image.

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