Quick object search using color histograms and pan-tilt-zoom camera?dynamic active search
Takahito Kawanishi, Hiroshi Murase · Electronics and Communications in Japan (Part II Electronics) · 2005
This paper proposes a method of searching for an object in a three-dimensional real environment at high speed using a pan-tilt-zoom camera. The method has been obtained by extending the “active search method,” which is a technique for searching for a specific object in an image at high speed. Objects in a real environment differ in their sizes and how they are observed, depending on differences in camera parameters, the directions of objects, and illumination conditions. Increasing the number of reference images corresponding to various observation methods is effective for handling the above differences, even though the search time is increased by simply increasing the number of images. In addition, when an object is distant, pan-tilt-zoom operations must be performed in stages, which increases the number of camera control operations. The proposed method reduces the time required for searching by using similarities in the histograms of the increased number of reference images. In addition, the number of camera control operations is reduced by dynamically using the proposed method in predicting camera control. Experiments have confirmed the effectiveness of the proposed method, showing that it can find small objects within 5 m of the camera in a real environment, and improves the search speed by a factor of over four compared with the conventional active search method and the conventional method using simple camera control. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 88(5): 40–49, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20179