JPH06153051A - Mobile objection tracking image pickup device - Google Patents

Abstract

PURPOSE:To always pick up a mobile objection within a screen by rotary-driving a camera in accordance with the movement of the mobile objection by detecting it from the image pickup device. CONSTITUTION:The video signal of a panoramic TV camera 21 is temporarily accumulated in a frame memory 22 and the next output video signal of the TV camera 21 and the accumulation signal of the memory 22 are subtract- processed at each picture element by a picture element differential arithmetic circuit 23 so as to extract a differential signal, namely, a mobile area. The differential signal is converted to a binary differential signal by a threshold value decided by a binary circuit 24. In a mobile area block detection circuit 25, an image pickup area is divided into prescribed blocks to count the number of picture elements over the threshold value at the time of binarization by each block to decide the block whose total number of the picture elements is over a previously-decided numerical value to be a mobile area block to output a block differential signal. The numerical value to be used for decision is set to be a value which can sufficiently remove a noise such as a fricker, etc. Thus. an image which always pickup the aiming mobile objection within the screen can be outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving object tracking image pickup device, and more particularly, it detects a moving region from a screen image picked up by one of the television cameras to extract the moving object so as to match the movement of the other object. The present invention relates to a moving object tracking image pickup device for tracking and picking up a moving object by driving the television camera.

[0002]

2. Description of the Related Art In a television lecture apparatus for transmitting video and audio information of a lecture scene to a remote place, generally, a lecturer located at a teacher's desk is imaged by a television camera for the lecturer. When moving on the platform, the instructor will be off the screen of the TV camera. A cameraman may manually adjust the camera angle in order to fit the instructor moving away from the teacher's table on the screen of the TV camera, but this method, which requires manpower, is not efficient. As a device that solves this difficulty, there is a moving object tracking imaging device that rotates a television camera in accordance with the movement of the lecturer.

FIG. 1 is a diagram for explaining a conventional example of a moving object tracking image pickup apparatus. Reference numeral 11 is a tracking TV camera, 12 is an electric rotary table, 13 is an angle signal generating circuit, 14 is a position detecting circuit, and 15 is a teacher. It is a mat switch installed in. During the television lecture, the instructor 16 is often located near the desk 17, but may move in front of the blackboard or other background 18. In order to detect this movement, a plurality of mat switches 15 are installed on the floor of the movement area. When the teacher 16 moves on the mat switch 15, the mat switch 15 pressed by the teacher 16 generates a pressure signal. The position detection circuit 14 decodes this pressure signal to identify which mat switch 15 generated the pressure signal, and outputs the position signal corresponding to the pressure signal to the angle signal generation circuit 1.
Output to 3. The angle signal generation circuit 13 determines a predetermined rotation angle based on the position signal, and supplies an angle signal for driving the rotation angle to the electric rotary base 12. The tracking TV camera 11 on the electric rotating table 12 constantly images the instructor 16, and even if the instructor 16 moves, the image of the instructor can be continuously captured in the center of the screen. Therefore, even if a person is taking a lecture in a remote place,
You can always observe the movement.

[0004]

The moving object tracking image pickup device shown in FIG. 1 requires a mat switch to be installed, and the device scale is large.
There is also a problem that only the teacher at the place where the mat switch is installed can detect it. The present invention detects a moving object such as a person from the imaged screen, and drives the television camera in accordance with the movement of the moving object to constantly capture the moving object in the imaging area, thereby solving the above-described problem. The present invention provides a moving object tracking imaging device that has been resolved.

[0005]

[Means for Solving the Problems] First television camera 21
And a second TV camera 11 installed on the electric rotating table 12.
A pixel difference calculation circuit 23 that calculates an inter-frame difference of a video signal output from the first television camera 21; and an inter-frame difference video area that is divided into m × n areas. A moving area block detection circuit 25 that determines an area having a difference value equal to or more than a certain value to be a moving area block, and a center in the horizontal direction from the leftmost block and the rightmost block of those that are determined to be moving area blocks. A center coordinate determination circuit 26 that determines the block coordinates and determines the coordinates of the central block in the vertical direction from the uppermost block and the lowermost block, and an angle signal that drives a predetermined rotation amount based on the determined central coordinates. Angle signal generating circuit 27 for generating
And an electric rotating base 12 for rotating and driving the second television camera 11 by an angle signal.

[0006]

Embodiments of the present invention will be described with reference to FIGS. First, in the block diagram 2, 21 is a panoramic television camera, 22 is a frame memory, 23 is a pixel difference calculation circuit, 24 is a binarization circuit, 25 is a moving area block detection circuit, 26 is a center coordinate determination circuit, and 27 is The angle signal generating circuit 28 is a video output terminal.

FIG. 3 is a diagram showing the arrangement of a tracking TV camera 11 and a panoramic TV camera 21 whose image is taken by a lecturer in a TV lecture. TV camera for foreground 2
The installation position of 1 may be the upper part of the tracking TV camera 11 or the upper part of the instructor 16. Hereinafter, a case where the foreground TV camera 21 is installed above the tracking TV camera 11 will be described.

The video signal output of the panoramic TV camera 21 for picking up a wide scene on the platform has n ₁ × n ₂ pixels, and this video signal is temporarily stored in the frame memory 22. The video signal stored in the frame memory 22 and the output video signal of the next frame of the panoramic TV camera 21 are subjected to subtraction processing for each pixel by the pixel difference calculation circuit 23, and a difference signal between the two frame video signals is extracted. . That is, a region having movement between both frames is extracted. The difference signal output from the pixel difference calculation circuit 23 is binarized in the binarization circuit 24 by a predetermined threshold value for all n ₁ × n ₂ pixels, and the binarized difference signal. Is converted to. The threshold value used here is set to a value that allows the difference signal to be correctly detected in consideration of the contrast between the background and the target person. The binarized differential signal output from the binarization circuit 24 is, in the motion area block detection circuit 25, m (= n ₁ / k) × n (= n ₂ ) in the imaging area composed of n ₁ × n ₂ pixels. / K) blocks (k is a common divisor of n ₁ and n ₂ ), and the number of pixels above a threshold value when binarized for each block is counted, and the total number is predetermined. A block having a numerical value equal to or larger than the specified value is determined as a moving area block, and a block difference signal is output. The numerical value used for the determination here is set to a value that can sufficiently remove flicker and other noise.

FIG. 4 is a diagram for explaining how to determine the center coordinates of the moving area. Reference numeral 32 shows an example of a block screen output from the moving area block detection circuit 25. The horizontal direction is indicated by x, and the vertical direction is indicated by y. This screen 32 is an example of the generation of a moving area block when the person image 31 moves. The shaded blocks indicate blocks that have been determined to be motion area blocks. In the central coordinate determining circuit 26, as shown in FIG. 4, the leftmost moving area block X _l in the screen 32 is displayed.
And the rightmost moving area block Xr determine the horizontal center coordinate Xc, and the uppermost moving area block Yt and the lowermost moving area block Yu allow vertical center coordinates Yc.
Ask for. The angle signal generating circuit 27 has a center coordinate (Xc,
Based on Yc), a rotation angle is calculated as described below, an angle signal for driving a predetermined rotation amount is generated, and this is transmitted to the electric rotary base 12.

FIG. 5 illustrates the rotation angle of the tracking TV camera 11 on the horizontal plane. Here, 41 is an image pickup screen of the panoramic TV camera 21, 42 is an image pickup screen of the tracking TV camera 11, and 43 is a moving area portion caused by the movement of the target person. The panoramic TV camera 21 and the tracking TV camera 11 are installed so that the optical axis in the direction perpendicular to the x axis is common. Also,
When the moving area portion 43 is at the center of the image pickup screen 41, the television camera is installed so that the image pickup screen 42 is output when the tracking television camera 11 has a rotation angle of 0 degrees. Furthermore, the moving area unit 4
When 3 is moved to the right end of the image pickup screen 41, that is, when it is moved rightward by the distance L on the x-axis of the image pickup screen 41, the rotation angle of the tracking TV camera 11 is α. In this state, the distance x on the x-axis of the imaging screen 41
Let θ be the rotation angle of the tracking TV camera 11 when is moved, the following relational expression holds.

Tan θ / tan α = X / L From this equation, the rotation angle θ of the tracking television camera 11 can be obtained by the following equation. θ = tan ⁻¹ xd where d = tan α / L. An angle signal for driving the rotation angle obtained by the above calculation is transmitted to the electric rotary base 12. The electric turntable 12 uses the angle signal transmitted from the angle signal generating circuit 27 to track the television camera 11 for tracking.
Is driven to rotate in a predetermined direction. TV camera for tracking 11
Takes an image of the target person and outputs a video signal via the video output terminal 28.

The above description is for the case where the panoramic TV camera 21 is installed above the tracking TV camera 11, but the installation position is the panoramic TV camera 21.
May be anywhere as long as it can capture an image of the entire moving range of the person to be tracked. For example, even if it is installed above the teacher 16 as shown in FIG.
It is possible to detect and track a moving area as the number 6 moves.

When the moving object is a person, the person area can be detected by its slight movement. Further, when the movement is completely stopped, the person can always be imaged by keeping the electric turntable 12 at that position. In the above description, the moving object is assumed to be a person in a television lecture, but it goes without saying that the present invention can be applied to tracking of a person for purposes other than television lecture, and tracking of a moving object other than a person. .

[0014]

As described above, the moving object tracking image pickup device of the present invention automatically drives the television camera to rotate in accordance with the movement of a person or other moving object without the intervention of a cameraman or other human hand. Therefore, it is possible to output an image in which the moving object of interest is always captured in the screen.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a conventional example of a moving object tracking imaging device.

FIG. 2 is a block diagram illustrating an embodiment of a moving object tracking imaging device of the present invention.

FIG. 3 is a diagram showing an arrangement example of a tracking TV camera and a panoramic TV camera whose target is a lecturer in a TV lecture.

FIG. 4 is a diagram illustrating a method of determining center coordinates of a moving area.

FIG. 5 is a diagram illustrating a rotation angle of a tracking TV camera.

[Explanation of symbols]

 11 Second TV Camera 12 Electric Rotating Platform 21 First TV Camera 23 Pixel Difference Calculation Circuit 25 Motion Area Block Detection Circuit 26 Center Coordinate Determination Circuit 27 Angle Signal Generation Circuit

Claims (1)

[Claims] 1. A first TV camera, a second TV camera installed on an electric rotating base, a pixel difference calculation circuit for calculating a difference between frames of a video signal output from the first TV camera, and a frame. The inter-difference video region is divided into m × n regions, and a moving region block detection circuit that determines a region having a difference value of a certain value or more as a moving region block from among the divided regions, and a moving region block is determined. A center coordinate determination circuit that determines the horizontal center block coordinates from the leftmost block and the rightmost block, and also determines the vertical center block coordinates from the top block and bottom block. And an angle signal generation circuit that generates an angle signal that drives a predetermined amount of rotation based on the determined center coordinates, and an electric rotary base that drives the second television camera to rotate by the angle signal. Moving object tracking image pickup apparatus characterized by Bei.