Imaging apparatus and subject tracking method

Abstract

The invention provides an imaging apparatus and a subject tracking method. If there is no movement of the imaging apparatus and no subject presence estimation region, normal tracking setting is accomplished (step S203), while if there is a subject presence estimation region, tracking setting is accomplished by expanding the detection range and lowering the detection threshold value (step S204). If the imaging apparatus is moving and there is no subject presence estimation region, normal tracking settings are accomplished (step S208), while if there is a subject presence estimation region, a determination is made as to whether or not that region is one with no flow (movement vector) detected. If this is a region with no flow detected, tracking settings are accomplished by expanding the detection range and using normal detection threshold values (step S207). If there is a region with flow detected, tracking settings are made by expanding the detection range and lowering the detection threshold value (step S204).

Description

technical field [0001] The invention relates to a camera and a method for tracking an object to be photographed. Background technique [0002] An imaging device having a function of sequentially detecting the position of a moving subject is known. For example, there is a technique of tracking a subject using template matching (also called block matching). For example, the image monitoring device described in Patent Document 1 (JP Laid-Open No. 2001-076156) retrieves and extracts from the previous frame image (image including the subject to be tracked) from the search range of the current frame image. The small image regions that are similar to the templates are detected, and the small image regions with the highest similarity are detected. In addition, it is determined that the subject is moving within the detected small image area. Also, if the frame image is captured again, by updating the detected small image area as a template and repeating the above operation, it is ...

AI Technical Summary

Problems solved by technology

[0003] However, according to the technique described in Patent Document 1, since block matching is performed on the same search condition regardless of the motion of the object to be photographed, for example, when the motion of the object to be photographed changes drastically in the frame image, it cannot Issues with performing block matching for subjects with dramatic changes in motion

[0004] Specifically, in the case of a wide shooting angle of view such as wide-angle photography and almost no movement of the subject, there is a problem of an unnecessary increase in the amount of computation.

In addition, in the case of a narrow shooting angle of view such as telephoto and the movement of the subject is intense, there is a problem that the subject cannot be tracked because the possibility of the subject moving out of the search range is high.

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