JPH089227A - Image pickup device with automatic tracking function - Google Patents

Abstract

PURPOSE:To stably extract a target object by using position information to separate and extract a tracking object and the others and taking the moving state of the target object, which is being tracked, into consideration. CONSTITUTION:The video signal obtained by an image pickup part 1 is outputted as a video signal, and a picture extracting part 2 separates a part satisfying the indicated feature values from the input signal in accordance with feature variables (hue, saturation, luminance, etc.,) indicated by a feature designating part 3. Thereafter, the position (for example, the address on X-Y coordinates) of the separated part on the reproduced picture is counted by a position detecting part 4, and this position information is fed back to the picture extracting part 2 to designate the position of extraction discrimination. If the object satisfying the designated fearures disappears in the picture, the picture extracting part 2 (or the position detecting part 4) requests a position storage part 5 to stop the update of position information. The storage part accepts the request to hold the position information at the time of acceptance of the stop request until the restart of update is requested.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tracking photographing apparatus for a video camera or the like, and more particularly to re-identification of a tracking target after a change in the state of a tracking target subject (missing, exceeding trackable range, separating, etc.)

[0002]

2. Description of the Related Art A conventional device is, for example, Japanese Patent Publication No. 5-607.
When the target subject goes out of the screen (outside the tracking possible range) as described in Japanese Patent No. 13 publication, the tracking operation is stopped at that point and the tracking field of view is returned to the initial value after a lapse of a predetermined time. There was.

[0003]

According to the above-mentioned conventional technique, unstable focus fluctuation is caused by maintaining focus control until the target object is lost and a new tracking target is captured at the initial position. The tracking target can be switched smoothly by preventing this. However, the subject to be tracked next does not always come in at the initial position, and the tracking target often switches undesirably, such that the subject often appears or disappears with large movements or other subjects that are out of the tracking range. However, it was not suitable for the purpose of continuously tracking a moving subject.

An object of the present invention is to provide an automatic tracking and photographing apparatus suitable for the above-mentioned purpose by stably and continuously recognizing and extracting a specific object.

[0005]

In order to achieve the above object, in the case where a subject which has been a tracking target until the previous time point disappears from the screen, the place where the tracking target existed at the previous time point or the initial position ( For example, the center of the screen) is used as the center to wait for a specific object to return.

Further, in addition to the features (conditions) designated in advance for recognition / extraction, the static / dynamic features (state) obtained from the recognized / extracted subject are taken into consideration, and the features designated in advance. Among the subjects (candidates) that match with, the one with the smallest state change is selected (specified) so that the same subject is continuously followed.

[0007]

[Operation] The image processing unit searches the screen for a subject matching the specified extraction condition, and at each time (for example, for each field)
Get location information of. The tracking control unit normally controls the movement of the photographing field angle so that the subject is located at the center of the screen based on the position information. When a plurality of subjects matching the extraction conditions are detected, the position of the tracking target subject at the previous time stored is compared with the current position, and it is considered that the subject was the tracking target until the previous time. One is selected, and the movement control of the photographing field angle is performed for the selected subject.
This makes it possible to continuously track the same subject even when there are a plurality of subjects having similar characteristics in the shooting screen.

Further, when the subject tracked up to the previous time point is lost for some reason, the tracking operation is held near the stored subject position at the previous time point, so that the camera side is rotated or the like. Even if the target to be tracked cannot be specified temporarily due to a change in the facing surface or the shadow of another subject, the tracking operation will be restarted from that location when the condition is restored, so tracking shooting without discomfort is possible. Becomes

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The video signal obtained from the image pickup unit 1 is output as a video signal, and is input to the image extraction unit 2. In the image extraction unit 2, the feature value (hue,
According to (saturation, brightness, etc.), a part of the input signal that satisfies the designated feature value is separated. After that, the position detecting unit 4 detects the position (for example, X-
The address at the Y coordinate) is counted. The counted position information is returned to the image extraction unit 2 and the position for extraction determination is designated. As a result, the once extracted object is stably extracted as long as it does not disappear due to sudden movement or obscuration, and similar feature values that exist at the same time in the screen unless overlap occurs. It is also possible to distinguish from an object having. At the same time, the position information is sent to the position storage unit 5 and is sequentially updated. The angle-of-view control unit 6 performs operations such as pan and tilt so that the target subject being photographed is located at the center of the screen based on the subject position information in the position storage unit 5. It should be noted that the operation can be realized by well-known CCD sensor scanning (reading position) varying means such as a camera shake correction function, a device used for remote operation photographing, and the like. In the normal state (a state where image extraction and position detection are properly performed), the position storage unit 5 is sequentially supplied with new position information as described above, and the stored value is updated accordingly. However, if the target subject disappears, the position cannot be detected. Therefore, when the disappearance of the image to be extracted is recognized in the image extracting unit, that is, when there is no object satisfying the specified characteristics in the screen, the image extracting unit 2 (or the position detecting unit 4) is the position storing unit. A request to stop updating the position information is made to 5. The storage unit that has received the request displays the position information at the time when the stop request is received until there is a request to restart the update, that is, until an object satisfying the specified characteristics appears again on the screen due to the disappearance of the subject returning or the like. Hold. As a result,
Even if the target object is blocked between the camera and the target object, the processing equivalent to the presence of the target object in the same place continues, and the foreign object moves and the target object returns. Since the extraction and the position detection are restarted, stable tracking operation is realized.

Next, a second embodiment of the present invention will be described with reference to FIG.
(FIG. 4) will be described. In the first embodiment described above, the object is waiting to be returned at a position immediately before the target object is lost, but in the second embodiment, a search is actively performed when the object disappears (is lost). Is. For example, when the moving object of the tracking target is hidden behind another object, the tracking target is temporarily lost (3b) as in the above case, and the target object moves during the (missing). If it does, it is difficult to restart the tracking operation even if the standby is continued at the position at the previous time (3c). Therefore, if the recovery of the target object is not confirmed even after waiting for a predetermined period, the designation of the image extraction position is sequentially changed centering on the detection position immediately before the point of missing (3d). This avoids the phenomenon that the tracking operation freezes even if the target object moves while the target object is lost. At this time, instead of centering the position immediately before as described above, the center may be the initial position (for example, the screen center),
Further, the search range may be limited to only the periphery of the center position or may be the entire screen, and the search range can be expanded by using the image control means together as shown in FIG.

Next, a third embodiment of the present invention will be described. In the third embodiment, the moving direction and speed of the tracking target subject at the previous time point are monitored, and if the target object is lost, it is assumed that the motion state at the previous time point is maintained and the image extraction position is designated. Is to be updated. As a result, even if the target subject being tracked disappears from the screen temporarily (5b) as shown in FIG. 5, for example, the tracking operation (and the angle of view control) continues. (5c), stable and smooth tracking operation is realized. Furthermore, by combining the second embodiment described above, it is possible to deal with changes in the motion state (direction, speed) during disappearance.

[0012]

As described above, according to the present invention, in addition to appearance features such as color and brightness, position information is used to separate and extract a tracking target object and a non-target object. Since the motion state of the target subject is also taken into consideration, stable extraction of the target subject can be expected even when a plurality of subjects are approaching, intersecting, temporarily disappearing, etc., and it is effective in realizing a smooth automatic tracking function.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an operation outline diagram showing an embodiment of the present invention.

FIG. 3 is an operation outline diagram showing an embodiment of the present invention.

FIG. 4 is an operation outline diagram showing an embodiment of the present invention.

FIG. 5 is an operation outline diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Imaging part, 2 ... Image extraction part, 3 ... Feature specification part, 4 ... Position detection part, 5 ... Position storage part, 6 ... View angle control part.

Claims (6)

[Claims] 1. A feature specifying unit for recognizing and extracting a specific object in a shooting screen, an image extracting unit for extracting a portion that matches the specified feature, and a position of the extracted image is measured. Means, means for returning the measured position information to the image extracting means, the image extracting means for extracting only the returned position, and a shooting angle of view such as pan, tilt, zoom, etc. Means for controlling the photographing angle of view changing means based on the position information of the extracted object, controlling the angle of view so that the extracted specific object is located at the center of the photographing screen, and tracking the target object. In the imaging device configured as described above, including means for storing the position information of the extracted object,
An imaging apparatus having an automatic tracking function, characterized in that when the object disappears from the screen, the appearance of the object to be extracted is waited at the stored position before the disappearance. 2. The method according to claim 1, further comprising means for arbitrarily designating an extraction position, wherein the designation of the extraction position is changed by changing the designation of the extraction position when the extracted object disappears or is lost from the screen. An image pickup apparatus having an automatic tracking function, characterized in that a searched object is searched. 3. The apparatus according to claim 1, further comprising means for arbitrarily designating an extraction position, and when the extracted object disappears or is lost from the screen, the designation of the extraction position is returned to the initial position for extraction. An imaging device having an automatic tracking function, characterized in that it waits for the appearance of a power object. 4. An image pickup having an automatic tracking function according to claim 1, wherein a standby mode with a fixed extraction designated position and a search mode with a variable extraction designated position are alternately switched. apparatus. 5. The pan / tilt at the time of search according to claim 1, 2, 3 or 4, wherein the pan / tilt / zoom or other means for varying the shooting angle of view is used to move the shooting angle of view to a wide angle side. An image pickup apparatus having an automatic tracking function, characterized in that the search range is widened by using the above together. 6. The method according to claim 1, further comprising means for storing information on the shape (size) of the extracted tracking target object, the moving direction, the speed, etc., and the object under tracking is separated into a plurality of pieces. And comparing the stored information with the current state, preferentially selecting an object closest to the immediately previous state, and continuously tracking the selected object. An imaging device having an automatic tracking function.