Measurement sensitivity enhancement by improved reflective computer vision technique for non-destructive evaluation

This paper presents an improved reflective computer vision technique, which is based on the optical interference. The improved technique eliminates the use of the computer-generated and monitor-display fringe pattern in the traditional reflective computer vision method. Instead, an optical interference fringe pattern having an analog resolution is produced by a two-point source of coherent light; hence, the fringe phase determination is no longer subjected to the depth resolution of the computer-monitor. With the use of higher gray-level image digitizers, the sensitivity of the fringe phase determination would be proportionally increased. In this paper, the principle and the instrumentation of the improved technique are presented. In addition, experimental demonstration of the improved technique in the non-destructive evaluation field is also included.