Field Line Detection Based on Local-precise Extracting and Modified Hough Transform

In Robocup, the field lines provide robots with the most useful information to make self-locating and strategies. For real-time competitions, the detection must be efficient. In this paper, we present a novel method of line detection based on fast edge extraction and modified Hough Transform. In this study, the condition of different objects´ distances is considered according to the camera angle. In the first step of edge extraction, an image is roughly scanned. A local-precise scanning is then implemented in regions where there may be edge points. After all feature points are picked out, a modified Hough Transform is used to extract lines. The result demonstrates that combining with real-time conditions, such as the angle of the camera and the distances of the objects on court, plays an important role in object detection.