Contour-based strike zone shaping and visualization in broadcast baseball video: providing reference for pitch location positioning and strike/ball judgment

Abstract

The strike zone plays a crucial role in baseball. Pitches which pass through the strike zone count as strikes, three of which strike out the batter. Besides strike/ball judgment, the strike zone also provides the reference for positioning pitch locations, about which sports fans and professionals have an intense interest in compiling statistics. This paper presents contour-based strike zone shaping and visualization in broadcast baseball video. We first detect the home plate, which determines the vertical limits of the strike zone. Then, an efficient algorithm is designed for batter contouring and the points of curvature extremes on the batter's contour are computed to locate the dominant points which determine the horizontal limits of the strike zone. The experiments show that the proposed framework is able to shape the strike zone fairly well in various baseball sequences, needless of manual operation and additional camera setting. The proposed strike zone shaping and visualization will be able to assist in pitch analysis and statistics compiling.