3次元動態計測システムとその応用

抄録

A measurement system for the three-dimensional position using "SELSPOT" is shown, which has many advantages over the methods with photographs, movies, or other devices, with respect to its on-line measurement, easy operation, fast sampling, fast data processing, and high accuracy. This is important in view of the application that the display of the analyzed data is required soon after the measurement, such as the experiment of sports physiology and rehabilitation. The system is constructed with a measurement subsystem and an analyzing subsystem. The measurement subsystem is constructed with the dual two-dimensional measurement device which is named "SELSPOT", a communication and timing controller, microcomputer for the filing of the data, and external memory devices. The analyzing subsystem is constructed with the random scan type graphic display with the light pen and ten-keyboard for the interactive analysis, the line printer for the numerical data, and the x-y plotter for the hard copy of the screen. This paper proposes a precise method with which the three-dimensional position is calculated from the dual two-dimensional data. This method defines it as the generalized inverse of the characteristic equation on the camera and the detective device, or the middle point of the segment which determines the minimum length of the two principle rays. By the analysis of the detective device and the lens system, the three factors of the following measurement errors and the methods of their compensation is considered: the non-linearity of the position sensitive detector with the distance between the camera and the LED, the interference of the lightning in the experiment room, and the distortion of the lens. On the other hand, this paper also proposes a new method for camera setting which causes the least error in the calculated data. In the results, the worst accuracy is ±0.4% with error compensation, and ±2.0% without the compensation, respectively. In addition, as the software of the analyzing subsystem realizes the interactive processing and the sufficient function, the period for the display and analysis of the three-dimensional movement is shortened.