JP2005236508A - Automatic tracking device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide automatic tracking device and method capable of performing tracking stably with no interruption at the time of tracking an object, e.g. an intruder, in an image. <P>SOLUTION: A template setting section 102 registers the object region in an image inputted from an image input section 101 as a template image. A template matching section 103 searches a region having high correlation with a registered template image among new input images by correlation operation. An apparent profile variation detecting section 104 detects apparent variation in profile of the object under search in template matching process. Depending on detection results from the apparent profile variation detecting section 104, a template holding control section 105 alters the upper limit of the holding number of template images or the update frequency of template when the apparent profile of the tracking object varies significantly. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an automatic tracking device and an automatic tracking method for tracking a specific object in a captured image in a monitoring system for an intruding object or the like.

  Remote monitoring camera systems have become widespread, and it has become possible to monitor an image taken at a specific point in a remote place and track an intruder or the like. Cameras used in surveillance camera systems are generally equipped with a wide-angle lens as a photographic lens to monitor a wide area, and although it is possible to determine the presence or absence of an intruding object, details such as the intruder's human phase and facial expression, etc. Has a drawback that cannot be grasped.

  Therefore, in addition to cameras equipped with wide-angle lenses, cameras equipped with pan, tilt, and zoom (hereinafter collectively referred to as PTZ) functions are installed, and the details of the intruder's human phase, etc. are controlled by the PTZ control of the observer. There is a monitoring system that can acquire a simple image (Non-Patent Document 1). However, manual operation of a camera having a PTZ function using an operation device such as a joystick to keep track of an intruder requires advanced technology, and many observers feel difficulty. Therefore, an automatic tracking device that can automatically track a tracking object such as an intruder in a captured image using an image recognition technique is desired.

  As an apparatus capable of such automatic tracking, an object tracking method and an object tracking apparatus using a template matching method have been proposed (Patent Document 1). Template matching is a method in which a partial image obtained by cutting out an image area of a tracking object at a certain time is used as a template image, and an area having the highest correlation with the template image is obtained by correlation calculation or the like in images at different times, and the tracking object is tracked. is there.

  FIG. 8 is a flowchart showing the operation at the time of object tracking in the conventional example of Patent Document 1. First, object detection processing is performed on an input image at a certain time t1 (step 901), and an image of the detected object region is registered as an initial template image (step 902). Next, an input image at a new time t2 is input (step 903), template matching is performed to detect a region having the highest correlation with the template image from the input image, and the object is tracked (step 904).

  Then, it is determined whether template matching processing has been performed for all stored template images (step 905). If all template matching processing has been completed, maximum matching determination processing is performed (step 906). ). If all the template matching processes are not completed, the template matching process in step 904 is repeated until the template matching process is completed.

  In step 906, if the maximum matching degree is equal to or smaller than the predetermined value, it is determined that there is no tracking object in the input image, and the process returns to step 901 to perform object detection processing again. On the other hand, when the maximum matching degree is a predetermined value or more, the position of the template image is corrected according to the result of template matching (step 907), and the corrected plurality of template images are stored (step 908). The plurality of template images are template images related to the same object although the acquisition time or update time is different and the appearance is slightly different. Subsequently, the camera platform is controlled so that the optical axis direction of the camera faces the tracking object (step 909). Then, for example, when the tracked object is present within a predetermined alarm range, an alarm is sounded or an image of the tracked object is displayed on the monitoring monitor (step 910).

JP 2001-60269 A Ushita, Fujiwara, Tadami, “Swinging, Tracking Intrusion Monitoring System Using Zoom Camera”, IEICE Technical Report PRMU 99-67 (P23-30), September 1999

  However, in the conventional automatic tracking method as described above, inappropriate data having a large difference from the apparent shape of the latest tracked object and having a high correlation with the background region is retained in a plurality of template images. There was a case. In such a case, erroneous correspondence to the background is likely to occur in template matching, resulting in a problem that tracking of the tracked object is interrupted and tracking is likely to fail.

  The present invention has been made in view of the above circumstances, and provides an automatic tracking device and an automatic tracking method capable of stable tracking without tracking interruption when tracking an object such as an intruder in an image. With the goal.

  An automatic tracking device according to the present invention is an automatic tracking device that inputs an image captured by an imaging unit and tracks a target object in the image, and correlates a template image indicating the characteristics of the target object with an input image. A template matching means for performing calculation, a shape change detecting means for detecting a shape change of the target object, and a template holding control means for controlling an update algorithm of the template image in accordance with a processing result of the shape change detecting means. It is to be prepared.

  With this configuration, for example, when there is a change in the shape of the target object, the content stored in the template image can be adaptively changed by changing the template image update algorithm, and the object can be tracked more stably. Is possible. As the template image update algorithm, for example, since a plurality of template images are normally held and correlation calculation is performed, there are an upper limit number of templates to be held, a template image update frequency, and the like.

  Further, as one aspect of the present invention, in the automatic tracking device described above, the shape change detection unit has a large apparent change when the target object moves in a direction crossing the optical axis of the imaging unit, In the case of moving in the direction along the optical axis, it is included that it is determined that the apparent change is small.

  With this configuration, it is possible to appropriately determine a change in the shape of the target object according to the moving direction of the target object, and it is possible to appropriately control the content held in the template image.

  Also, as one aspect of the present invention, in the automatic tracking device described above, the shape change detection unit may change the apparent change of the target object when a pan / tilt angle or a zoom ratio of the imaging unit is controlled to a predetermined value or more. Also included are those that are judged to have occurred.

  With this configuration, it is possible to appropriately determine a change in the shape of the target object based on the pan / tilt control amount or the zoom ratio control amount of the imaging unit, and the content held in the template image can be appropriately controlled. .

  Further, as one aspect of the present invention, in the automatic tracking device described above, the template holding control unit may detect the template image when the shape change detecting unit determines that the target object has a shape change. Also included are those that lower the retention limit.

  With this configuration, when there is a change in the shape of the target object, it is possible to reduce the retention of the template image having a high correlation with the background by reducing the upper limit of the number of template images retained. For this reason, it is possible to prevent the tracking of the object from being interrupted due to the template matching with the background, and it is possible to track the object more stably.

  Further, as one aspect of the present invention, in the automatic tracking device described above, the template holding control unit may detect the template image when the shape change detecting unit determines that the target object has a shape change. Some of them increase the update frequency.

  With this configuration, by increasing the update frequency of the template image when there is a change in the shape of the target object, the ratio of the template image updated at a relatively close time can be increased, and the object can be tracked more stably. It becomes possible.

  The automatic tracking method of the present invention is an automatic tracking method for inputting an image taken by an imaging means and tracking a target object in the image, and setting a template image indicating the characteristics of the target object in the input image. A template setting step, a template matching step for calculating a correlation between the new input image including the target object and the template image, a shape change detecting step for detecting a shape change of the target object, and the shape change detection process And a template holding control step for controlling an update algorithm of the template image according to the result.

  By this procedure, for example, when there is a change in the shape of the target object, the content stored in the template image can be adaptively changed by changing the template image update algorithm, and the object can be tracked more stably. Is possible.

  The present invention also provides a program for causing a computer to execute each procedure of the automatic tracking method. With this program, the automatic tracking method according to the present invention can be implemented by a computer. This program can also be stored in a recording medium such as a memory, a hard disk, or a CD-ROM.

  ADVANTAGE OF THE INVENTION According to this invention, when tracking objects, such as an intruder, in an image, the automatic tracking apparatus and automatic tracking method which can perform stable tracking without interruption of tracking can be provided.

  Hereinafter, as an embodiment of the present invention, in a remote monitoring system for monitoring an intruding object or the like, an object in a captured image is tracked using a template, and panning, tilting, and zooming operations (PTZ operation) of the camera are controlled in detail. An example of an automatic tracking device such as an automatic tracking camera for monitoring an intruding object and an automatic tracking method will be described.

(First embodiment)
FIG. 1 is a diagram showing a functional configuration of an automatic tracking apparatus according to the first embodiment of the present invention.

  The automatic tracking device 100 includes an image input unit 101 that inputs an image captured by the imaging device 108, a template setting unit 102 that registers an object region (target object region) in the input image as a template image, and an input image A template matching unit 103 that searches for a region having a high correlation with the registered template image from among the templates, an apparent shape change detection unit 104 that detects an apparent shape change of the target object being tracked in the template matching process, A template holding control unit 105 that controls the upper limit of the template holding number according to a change in the apparent shape, and an imaging device control unit that causes the imaging device 108 to perform a PTZ operation so that the target object appears (positions) in the center of the captured image. 106 and an image output unit 107 that outputs an image to an external image display device 109. It is configured to.

  In the present embodiment, for a captured image captured by the imaging device 108 and input from the image input unit 101, the template setting unit 102 registers an object region in the image as a template image and sets a template. Thereafter, for a new captured image input from the image input unit 101, the template matching unit 103 searches for a region having a high correlation with the registered template image. Here, when a change in the apparent shape of the object being tracked is detected, the upper limit of the number of saved template images is changed by the control of the template holding control unit 105 in accordance with the change in the appearance of the tracked object. For example, if it is determined that the apparent shape of the tracking object has changed significantly, the upper limit of the number of saved template images is lowered.

  Next, the operation of the main part of the automatic tracking device 100 will be described. First, the template setting unit 102 sets, as a template image, a rectangular area including pixels of an object area to be tracked from an input image (an image taken by the imaging device 108). As a setting method of the template image, the operator may manually set and operate the object region while looking at the input image, or the region where the luminance change has occurred in the input image is regarded as the object region. An area including pixels assigned with the same label after the labeling process may be automatically set as a template image.

  It is assumed that a plurality of template images are held for the same object with different acquisition times and update times, but a single template image may be used. When the correlation between the template image and the input image becomes low, the maximum number of templates that can be stored is added. When the maximum number is reached, delete some templates and add new ones. Examples of the template deletion rule include deletion from an old one, deletion from a lower correlation, and the like.

  The template setting method is not limited to the above example, and a pattern recognition technique may be used to set an object region as a template when a certain image region is recognized as an object to be tracked. The size of the template is generally set to a size including the entire object region, but a part of the object region such as the periphery of the head may be set as a template image. Further, the template image is cut out from the input image and is a part of the input image. However, the template image may be used without any particular processing, or may be used as a template image by performing edge extraction or various filter processes. .

  FIG. 2 is a diagram for explaining the operation of the template matching unit 103. The template matching unit 103 obtains a correlation between the new input image input from the image input unit 101 and the registered template image, and searches for a highly correlated area. In FIG. 2, the template image of the immediately preceding frame set by the template setting unit 102 as shown in FIG. 2A is set as a template image T, and the newly input input image as shown in FIG. To do. The template matching unit 103 searches the corresponding area 201 having the highest correlation with the template image T from the input image I. Here, the search for the corresponding region 201 can be repeated every tens to hundreds of milliseconds to track the object position. When there are a plurality of template images T, the search is performed using all target template images.

  At this time, a search range 202 of about several tens of pixels in the horizontal and vertical directions is set in the latest input image I with reference to the region having the highest correlation in the processing of the immediately preceding frame. When obtaining the correlation, the correlation with the template image T is sequentially obtained while scanning the search range 202. Although it is conceivable that the search range 202 is the entire input image, the search range is generally limited because the amount of calculation is too large or miscorrespondence is likely to occur. The width of the search range 202 is about several to several tens of pixels in the horizontal and vertical directions, depending on the movement of the object.

  An example of using normalized correlation as a method for calculating a correlation value in an image will be described. The size of the template image T is set to K (H) * L (V) pixels, and the template image T (p, q) is moved so that the rectangular area K (H) in the current frame image I (x, y) is moved. * L (V) pixels are assumed. The normalized correlation value NRML (xv, yv) between the template image T (p, q) and the rectangular area K (H) * L (V) pixel in the current frame image I (x, y) is expressed by the following formula ( It can be expressed as 1).

  The normalized correlation value NRML is closer to 1.0 as the correlation between both images is higher, and is 0 when there is no correlation. When an image having exactly the same pixel value as that of the template image T exists in the search range 202, the normalized correlation value NRML is 1.0. A position on the current frame having the highest correlation is defined as a corresponding area 201. The movement amount of the corresponding area 201 from the position of the template image extracted in the immediately preceding frame is (xv, yv), which indicates the motion vector of the template.

  In the above example, the method of obtaining a correlation value between a new input image and a template image by normalized correlation has been described. However, as a correlation value calculation method, a difference method or a difference absolute value sum method with a smaller amount of calculation is used. This method can also be used.

  The apparent shape change detection unit 104 detects that the apparent shape of the object being tracked has changed, and notifies the template holding control unit 105 described later. The change in the appearance of the tracked object can be determined using the moving direction of the intruder, for example.

  FIG. 3 is a diagram illustrating an example of a moving direction of an object and an apparent change in a captured image of the object. FIG. 3A illustrates a case of moving in a direction crossing the optical axis of the imaging apparatus, and FIG. The cases of moving in the direction along the optical axis are shown.

  When the tracking object 301 moves in a direction crossing the optical axis of the imaging device 302 such as a camera as shown in FIG. 3A, the tracking object 301 is initially observed from the front when viewed from the imaging device 302. The side will be observed as it moves, and the back will be observed as it moves further. In this case, in the captured image by the imaging device 302, a different surface is captured as the tracking object 301 moves. Therefore, the apparent shape change of the object moving in the horizontal direction in the captured image increases with the movement.

  When the tracking object 301 moves so as to follow the optical axis of the imaging device 302 as shown in FIG. 3B, when viewed from the imaging device 302, the tracking object 301 is always observed near the front, and the apparent per moving distance is observed. The change is small. At this time, if the zoom control is appropriately performed, the size of the object on the image can be made substantially constant. Therefore, the apparent shape change of an object moving in the vertical direction or depth direction in the captured image or an object having a small movement on the image is small. However, the apparent shape change becomes large regardless of the moving direction when the tilt angle (the depression angle) of the imaging device is large as in the case of passing under the imaging device.

  The moving direction of the tracking object can be grasped by integrating the number of moving pixels on the image obtained by template matching according to the direction, but in the case of an automatic tracking device, the object is always near the center of the image. Since the imaging apparatus itself is pan-tilt controlled, the moving direction can be determined using this pan-tilt control amount.

  Therefore, the apparent shape change detection unit 104 has a large apparent change when the tracking object 301 moves in a direction crossing the optical axis of the imaging device 302, and when the tracking object 301 moves in a direction along the optical axis of the imaging device 302. Judge that the change in appearance is small. Alternatively, it is determined that an apparent change has occurred when the pan / tilt angle or the zoom ratio of the imaging device 302 is controlled to a predetermined value or more.

  The template holding control unit 105 receives the processing result of the apparent shape change detection unit 104, adaptively changes the upper limit of the number of held images, and then saves the template image. Although it is assumed that a plurality of template images are set and held for the same object, a single template image may be used. When the correlation between the template image and the input image becomes low, the template images are added up to the maximum number that can be stored. When the upper limit is reached, the template image is updated according to a predetermined rule. For example, after deleting the old one, add a new one. The relationship between the correlation value between the template image and the input image and the number of template images will be described below.

  When correlation calculation is performed in the template matching unit 103, a correlation value CORR between each template image and the input image, for example, a normalized correlation value NRML described in the above equation (1) is obtained as a result. Here, when the correlation value between the input image and the plurality of template images satisfies the condition of the following expression (2), the template image is added.

      Correlation value CORR ≦ correlation value threshold TH_CORR (2)

  If there are a plurality of template images, a plurality of correlation values can be obtained, and the maximum value is taken as the correlation value CORR of equation (2). That is, when the correlation value CORR between the plurality of template images and the input image is equal to or smaller than the predetermined correlation value threshold TH_CORR and the correlation becomes low, a new template is added.

  It is considered that the number of stored template images can cope with the shape change of the tracking object if it is held to some extent, but if it is too much, a template having a high correlation with the background pattern is likely to be stored. . In fact, if a large number of template images acquired over a long period of time are held, those having a high correlation with the background pattern are stored, and a phenomenon occurs in which the template is stuck on the background and object tracking is interrupted.

  Therefore, in this embodiment, when it is determined that the appearance of the object has changed significantly, the upper limit of the number of template images to be saved is made smaller than usual, and the template image that deteriorates the tracking performance is deleted and not used. . If the storage number upper limit has already been exceeded, some template images are deleted according to a predetermined rule. For example, as a rule to be deleted, it is possible to delete from the oldest one, or delete from the one having a low correlation with the tracking object by template matching.

  FIG. 4 is a flowchart showing a template image control operation by the template holding control unit 105 in the first embodiment.

  The template holding control unit 105 determines whether there is an apparent shape change of the tracked object based on the detection result in the apparent shape change detection unit 104 (step 401). If it is determined in step 401 that the apparent shape change of the tracking object is greater than or equal to a predetermined amount, the upper limit of the number of template images stored is reduced below normal (step 402). As a result, when the apparent shape of the tracked object changes greatly, the template image that degrades the tracking performance is deleted and is not used. If the storage number upper limit has already been exceeded, some template images are deleted according to a predetermined rule. On the other hand, if it is determined in step 401 that there is no change in the apparent shape of the tracked object, the process ends without changing the upper limit of the number of saved template images.

  The imaging device control unit 106 controls a camera driving mechanism that performs panning, tilting, and the like so that the optical axis of the camera of the imaging device 108 (the viewing direction of the camera) faces in the direction in which the tracking object exists. As a result, the imaging device 108 is driven and controlled so that the tracking object is positioned at the center of the captured image. At this time, the center position of the tracking object detected by template matching is compared with the center position of the input image, and the center position of the detected tracking object is shifted in the left-right direction with respect to the center position of the input image. Control the pan motor of the camera and adjust it by moving the optical axis of the camera in the horizontal direction. Further, when the center position of the tracking object is shifted in the vertical direction with respect to the center position of the input image, the camera is adjusted by moving the optical axis of the camera in the vertical direction by controlling the tilt motor of the camera.

  Next, the overall operation of the automatic tracking device of the first embodiment configured as described above will be described with reference to FIG. FIG. 5 is a flowchart showing an operation procedure of the automatic tracking device according to the first embodiment.

  First, the image input unit 101 inputs an image captured by the imaging device 108 (step 501). Then, the template setting unit 102 sets a template by registering an object region (a pixel region of an object to be tracked) in the input image as a template image (step 502). Next, an image newly captured by the imaging device 108 is input in the image input unit 101 (step 503).

  Then, the template matching unit 103 compares the new input image with the template image to calculate a correlation value, and searches for a region having a high correlation with the registered template image from the new input image (step 504). ). By this template matching process, the pixel position of the tracking object is extracted.

  Next, the apparent shape change detection unit 104 determines whether there is a change in the apparent shape of the tracked object, and notifies the template holding control unit 105 of the determination result (step 505). If it is determined that the apparent shape change of the tracking object is large, the template holding control unit 105 performs control so as to lower the upper limit of the number of template images held in accordance with the change in the appearance of the tracking object (step 506). On the other hand, if it is determined that the apparent shape change of the tracking object is small, step 506 is skipped. Note that when the upper limit of template retention is lowered and the upper limit of template retention is exceeded, some template images are deleted.

  Then, the template holding control unit 105 determines whether the correlation value between the input image and the template image is equal to or less than a predetermined threshold based on the processing result in the template matching unit 103, and updates the template image if it is equal to or less than the threshold. . Then, the updated template image is stored (step 507).

  Thereafter, the imaging device control unit 106 controls panning, tilting, and zooming of the imaging device 108 and causes the imaging device 108 to perform a PTZ operation so that the tracking object is positioned at the center of the image (step 508). Then, the monitoring area including the tracking object is imaged (step 509). Then, the image output unit 107 outputs the image captured by the imaging device 108 to an external image display device (step 510). Thereafter, the process returns to the new image input process in step 503, and the same process is repeated.

  As described above, in the automatic tracking device according to the first embodiment, the apparent shape change detection unit 104 determines the apparent shape change of the tracking target object based on the moving direction of the object, and there is an apparent shape change. In addition, the template image update algorithm used in the correlation calculation is changed. Specifically, the template storage control unit 105 reduces the upper limit of the number of template images stored. As described above, it is possible to reduce the storage of a template image having a high correlation with the background pattern by adaptively changing the held content of the template image according to the detection result of the apparent change of the tracking object. As a result, the tracking of the object can be prevented from being interrupted, and the object can be tracked more stably.

(Second Embodiment)
The second embodiment is an example in which the function of the template holding control unit 105 in the automatic tracking device 100 is changed. Other configurations and operations are the same as those of the first embodiment described above, and here, the description will focus on the features of the second embodiment.

  In the second embodiment, the template holding control unit 105 controls the template update frequency according to the change in the apparent shape of the target object. That is, the template holding control unit 105 receives the processing result of the apparent shape change detection unit 104, adaptively changes the image update frequency, and then stores the template image. The image input from the image input unit 101 is searched for a region having a high correlation with the registered template image in the template matching unit 103, and when an apparent change in the object being tracked is detected, the amount of change is determined. The template update frequency is changed under the control of the template holding control unit 605. At this time, if it is determined that the apparent shape of the object has changed significantly, the update frequency of the template image is set higher than usual.

  It is effective to have multiple template images to cope with changes in the shape of the object, but if the movement is accompanied by a relatively large change in the apparent shape, the template update frequency is increased, and more A template image close to the current shape can be held. Specifically, when it is determined that the appearance has changed significantly, for example, the template value is updated more frequently by lowering the correlation value threshold used when updating the template as used in Equation (2). To change.

  FIG. 6 is a flowchart showing a template image control operation by the template holding control unit 105 according to the second embodiment.

  The template holding control unit 105 determines whether there is an apparent shape change of the tracked object based on the detection result in the apparent shape change detection unit 104 (step 601). If it is determined in step 601 that the apparent shape change of the tracking object is greater than or equal to a predetermined amount, the template image update frequency is increased (step 602). As a result, when the apparent shape of the tracking object changes greatly, the template image is updated more frequently. On the other hand, if it is determined in step 601 that there is no change in the apparent shape of the tracked object, the process ends without changing the update frequency of the template image.

  Next, the overall operation of the automatic tracking device according to the second embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing an operation procedure of the automatic tracking device according to the second embodiment.

  In FIG. 7, the procedure from the image input to the determination of the apparent change of the tracked object, that is, the operations in steps 501 to 505 are the same as those in the first embodiment shown in FIG. If it is determined in step 505 that the apparent shape change of the tracking object is large, the template holding control unit 105 controls the template image to be updated at a higher frequency according to the change in the tracking object appearance (step 706). On the other hand, if it is determined that the apparent shape change of the tracked object is small, step 706 is skipped. Note that the operations after the procedure for updating and saving the template image, that is, the operations after step 507 are the same as those in the first embodiment shown in FIG.

  As described above, in the automatic tracking device according to the second embodiment, the apparent shape change detection unit 104 determines the apparent shape change of the object to be tracked based on the moving direction of the object, and there is an apparent shape change. In addition, the template image update algorithm used in the correlation calculation is changed. Specifically, the template holding control unit 105 increases the update frequency of the template image. In this way, a template image closer to the current shape can be retained by control to adaptively change the retained content of the template image according to the detection result of the apparent change of the tracking object, and the apparent appearance of the tracking object can be retained. The object can be tracked more stably following the change in shape.

  The present invention has an effect of enabling stable tracking without tracking interruption when tracking an object such as an intruder in an image, and a specific object in a captured image is detected in a monitoring system such as an intruding object. This is useful for an automatic tracking device and an automatic tracking method for tracking.

The figure which shows the function structure of the automatic tracking apparatus which concerns on the 1st Embodiment of this invention. (A) The figure which shows the template image T of the last frame in operation | movement of the template matching part of this embodiment, (b) The figure which shows the input image I in operation | movement of the template matching part of this embodiment. (A) The figure which shows an example of an apparent change when an object moves to the direction which crosses the optical axis of an imaging device in this embodiment, (b) In this embodiment, an object moves to the direction along the optical axis of an imaging device. Showing an example of apparent change when 6 is a flowchart illustrating a template image control operation by the template holding control unit according to the first embodiment. The flowchart which shows the operation | movement procedure of the automatic tracking apparatus in 1st Embodiment. 8 is a flowchart showing a template image control operation by the template holding control unit according to the second embodiment. The flowchart which shows the operation | movement procedure of the automatic tracking apparatus in 2nd Embodiment. Flow chart showing the operation at the time of object tracking in the conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Automatic tracking apparatus 101 Image input part 102 Template setting part 103 Template matching part 104 Apparent shape change detection part 105 Template holding | maintenance control part 106 Imaging device control part 107 Image output part 108,302 Imaging device 109 Image display apparatus 301 Tracking object

Claims (7)

An automatic tracking device that inputs an image captured by an imaging unit and tracks a target object in the image,
Template matching means for performing a correlation operation between a template image indicating the characteristics of the target object and an input image;
A shape change detecting means for detecting a shape change of the target object;
An automatic tracking device comprising: a template holding control unit that controls an update algorithm of the template image according to a processing result of the shape change detection unit. The automatic tracking device according to claim 1,
The shape change detecting means has a large apparent change when the target object moves in a direction crossing the optical axis of the imaging means, and a small apparent change when the target object moves in a direction along the optical axis. An automatic tracking device characterized by judging. The automatic tracking device according to claim 1,
The automatic tracking device, wherein the shape change detecting means determines that an apparent change of the target object has occurred when a pan / tilt angle or a zoom ratio of the imaging means is controlled to a predetermined value or more. The automatic tracking device according to any one of claims 1 to 3,
The automatic tracking apparatus, wherein the template holding control means lowers the upper limit of the number of holding template images when the shape change detecting means determines that the target object has a shape change. The automatic tracking device according to any one of claims 1 to 3,
The automatic tracking device, wherein the template holding control means increases the update frequency of the template image when the shape change detecting means determines that the target object has a shape change. An automatic tracking method for inputting an image taken by an imaging means and tracking a target object in the image,
A template setting step for setting a template image indicating the characteristics of the target object in the input image;
A template matching step for performing a correlation operation between the new input image including the target object and the template image;
A shape change detecting step for detecting a shape change of the target object;
A template holding control step of controlling an update algorithm of the template image in accordance with a processing result of the shape change detection.   The program for making a computer perform each procedure of the automatic tracking method of Claim 6.

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