JPH0432376A - Picture tracking system - Google Patents

Abstract

PURPOSE:To improve the tracking characteristic by obtaining a camera angle fluctuation component caused between pickup period frames of a camera, generating a signal eliminating the angle fluctuation component from a deviation signal being an output of an object position deviation computing element and using the signal to control a camera driver. CONSTITUTION:A camera 1 and an angle detector 4 are placed on a camera driving device 2, and a picture signal picked up from an external field continuously and periodically by the camera 1 is fed to an object position deviation computing element 5, and the angle detector 4 detects an angle being a camera visual field reference with respect to a moment inertial reference synchronously with the camera pickup period and outputs the detection signal to the object position deviation computing element 5. Then the object position deviation computing element 5 obtains a deviation from a camera visual center O to a position of an object W, eliminate the angle fluctuation component of the camera 1 from the deviation signal and uses the result as a control signal and outputs it to the camera drive section 2. Thus, a waste time in existence in the tracking loop is eliminated and the tracking dynamic characteristic is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image tracking method that controls driving of a camera so that when a specific object is imaged by a camera, the specific object is always located in the center of the camera's field of view. In particular, it relates to an image tracking method that aims to improve tracking characteristics by compensating for dead time corresponding to the imaging cycle of the camera. It was equipped with a drive blade W2 and an object position deviation wave X device 3, and was configured as shown in the block diagram shown in FIG. That is, the camera 1 is installed in the camera drive device 12J-, and the deviation of the position of the object W captured by the camera 1 from the camera field of view center 0 is calculated by the object position deviation calculator 3, and based on the results of the 1,000 calculations. Camera drive device 2
A method was adopted in which the object W was tracked by controlling the .

FIG. 7 shows the operation timing of the above-mentioned image tracking system. An image is captured by a camera between time 1+ and t2, and the acquired image data is transferred to the next frame t,
- The operation of performing arithmetic processing on the first half of the previous three and outputting it as a drive signal to the drive device 2 was repeated.

``Problem to be Solved by the Invention'' In the conventional image tracking method described above, as can be seen from the block diagram shown in FIG. 5, deviation calculation processing is included in the tracking loop L, so the processing time is This becomes an element of wasted time and limits the dynamic characteristics of the tracking loop L.

Conventionally, as a measure to reduce the influence of this wasted time element, efforts were made to reduce the wasted time itself, that is, to reduce the amount of wasted time itself.
Efforts have been made only to increase the update rate of the imaging system and to reduce the processing time for deviation calculations.

However, there is a limit to the improvement of the imaging update rate and the reduction of the deviation calculation processing time, and there is a problem that this method cannot fundamentally solve the problem.

The present invention was made to solve such problems, and an object of the present invention is to provide an image tracking method that can eliminate wasted time in the tracking loop and improve tracking dynamic characteristics.

[Means for Solving the Problem] In order to achieve the above object, the image tracking method of the present invention has the following features:
A camera that continuously and periodically captures images of the outside world, a camera drive device that moves the viewing direction of the camera, and an object to be tracked is extracted for each frame from within each frame image captured by the camera. and an object position deviation calculator that outputs the deviation of the object position from the center of the camera field of view, and an angle detector that detects the angle of the camera field of view white reference with respect to the inertial reference in synchronization with the imaging cycle of the camera. , the camera takes pictures based on the output signal from the angle detector t1. An angular fluctuation component of the camera occurring between periodic frames is determined, a signal is generated by removing the angular fluctuation component from a deviation signal that is an output of the object position deviation calculator, and the camera driving device is controlled by the signal. This is the method.

Here, it is preferable that the angle detector is driven integrally with the camera by the camera driving device, and the camera field of view white reference is preferably the center of the camera field of view.

[Operation] 1-According to the present invention having the above-described configuration, it is possible to equivalently remove the dead time element from the tracking loop, and as a result,
It is possible to improve the tracking dynamic characteristics.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a block diagram, and FIG. 3 is a block diagram equivalent to FIG. 2.

In the image tracking system of this embodiment, a camera 1 and an angle detector 4 are mounted on a camera drive device 2.

From the camera l, an image signal obtained by continuously and periodically capturing images of the outside world is sent to the object position deviation calculator 5. Furthermore, the two-angle detector 4 is synchronized with the imaging cycle of the camera, in other words, it is a camera drive unit! In synchronization with the drive @ output timing to 2, the angle of the camera field of view white reference with respect to the inertial reference is detected, and the detection signal is output to the object position deviation calculator 5.8 Here, the camera field of view white reference and 17 , the center O of the camera field of view α is taken. FIG. 4 shows the relationship between the angle γ of the center of camera field of view O with respect to the inertial reference X and the angle angle of the object W, and these angles γ, angle, and angle are input to the object position deviation calculator 5.

The object position deviation calculator 5 has an additional @calculation function 5a, and the function 5a calculates the fluctuation component occurring between the imaging cycle frames of the angle γ of the camera field of view center O. The fluctuation component regarding the angle γ of the camera field of view center O is, in other words, the angle fluctuation component of the camera 1 that occurs between the imaging cycle frames.

The object position deviation calculator 5 (the blower in FIG. 2 includes the camera 1) calculates the distance between the camera field center O and the object W.
, and removes the angular fluctuation component of the camera 1 from this deviation signal, and outputs this to the camera drive unit 2 as a control l signal.

The image tracking system of this embodiment described above has a block configuration equivalent to that shown in FIG. 3, and since the arithmetic processing section E is placed outside the tracking loop I2, wasted time elements are eliminated.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without changing the gist.

[Effects of the Invention] As explained above, according to the present invention, it is possible to equivalently eliminate dead time existing in the tracking loop, thereby improving tracking dynamic characteristics and eliminating waste time occurring in the sample value control system. This has the effect of reducing limit cycles, etc. that tend to occur.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 2 is a block diagram, Fig. 3 is a block diagram equivalent to Fig. 2, and Fig. 4 shows the center of the camera field of view and the object. 5 is a schematic configuration diagram showing a conventional image tracking system, FIG. 6 is a block diagram of the same, and FIG. 7 is an operation timing diagram of the system. l: Camera 2. Camera drive device 4: Angle detector 5: Object position deviation calculator 1st II d: Melao wo Ichiko

Claims (3)

[Claims] (1) A camera that continuously and periodically images the outside world, a camera drive device that moves the viewing direction of the camera, and an object to be tracked that is extracted for each frame from the images of each frame captured by the camera. and an object position deviation calculator that outputs the deviation of the object position from the center of the camera field of view, and an angle detector that detects the angle of the reference within the camera field of view with respect to the inertial reference in synchronization with the imaging cycle of the camera. , based on the output signal from the angle detector, find an angular fluctuation component of the camera that occurs between the imaging cycle frames of the camera, and remove the angular fluctuation component from the deviation signal that is the output of the object position deviation calculator. An image tracking system characterized in that the camera driving device is controlled by the signal generated by the image tracking system. (2) The image tracking system according to claim 1, wherein the angle detector is driven integrally with the camera by the camera driving device. (3) The image tracking method according to claim 1 or 2, wherein the reference within the camera field of view is the center of the camera field of view.