民生用ビデオカメラによる3次元動作分析用,同期信号発生装置の試作  [in Japanese] Development of a synchronizing signal generator for 3D motion analysis with household camcorders  [in Japanese]

To analyze 3D motion with 2 household degital camcorders, a synchronizing signal generator constructed by 10 pairs of LEDs and the driving circuit was developed, Ten pieces of red colored 5 cm wide line tape were attached on a L-shaped 1 m long white angle bar at outside surfaces of L-shape with a distance of each 5 cm, and on each red area 2 green LEDs were mounted at both surfaces and these 2 LEDs were connected in series. At video recording, each pair of LEDs (ten pairs in total) were lighted successively for each 1/600 second (1/10 single field time) once each cycle by a singechip mycrocomputer, and this cycle was repeated at intervals of 1 second. The angle bar was set in the vicinity of right or left end of the camera angle, and both outside surfaces of L-shape were trained to 2 camcorders. When an exposure of a camcorder comes across the lighting cycle of LEDs, a certain position and number of LEDs, corresponding to the delay from the lighting of the first pair and the duration of the exposure respectively, are recorded to a camcorder. Based on these records, the time difference of each exposure of 2 camcorders could be calculated, and the coordinates of the subject in the screen image derived from one camcorder could be converted to those synchronized to another camcorder by interpolation