Robust Detection and Identification of Partially Occluded Circular Markers International Conference on Computer Vision Theory and Applications (VISAPP), located at VISIGRAPP, May 17-21, Angers, France

Robust Detection and Identification of Partially Occluded Circular Markers International Conference on Computer Vision Theory and Applications (VISAPP), located at VISIGRAPP, May 17-21, Angers, France
Johannes Köhler, Alain Pagani, Didier Stricker
International Conference on Computer Vision Theory and Applications International Conference on Computer Vision Theory and Applications (VISAPP), located at VISIGRAPP, May 17-21, Angers, France

Abstract:

In this paper we present a pipeline for the robust detection of partially occluded circular markers. Compared to square markers, occluded circular tags can be tracked in a more robust way, since the camera pose is in this case computed from the whole contour instead of only the four corners. We introduce a new ellipse detection technique based on a constrained RANSAC algorithm and pre-ellipse fit outlier removal to detect tag candidates with damaged borders. Digital codes are used to identify the actual markers afterwards, since correlation based marker identification approaches are not capable of handling occlusion. The key to error detection and correction is a suitable Reed Solomon code together with a proper code layout on the marker. We show that markers covered up to 30% can be detected, our tracker moreover has a very low risk of false positive marker detection.