Ozdemir A K, Takasu T, Shinohara S, Yoshida H, Sumi M
Shizuoka University, Hamamatsu, 432-8561 Japan.
Appl Opt. 1999 Apr 1;38(10):1968-74. doi: 10.1364/ao.38.001968.
A novel laser speckle velocimeter with two self-mixing laser diodes (SM-LD's) for velocity and length measurements of moving surfaces is reported. The mean frequency of the speckle signal obtained in the measurement system depends on the surface path illuminated by the SM-LD. This behavior of the speckle signal in the SM-LD's is exploited to detect the front and the end edges of a target surface by sampling continuously the number of intensity changes in a speckle signal waveform. Once the edges are determined, the velocity and the length of the surface are calculated easily. The error for length and velocity measurements of a target with a homogeneous rough plane surface of 60-mm length, moving at a velocity of 200 mm/s, can be as low as 2.1% and 1.75%, respectively.
报道了一种新型激光散斑测速仪，它采用两个自混合激光二极管（SM-LD）来测量运动表面的速度和长度。测量系统中获得的散斑信号的平均频率取决于SM-LD照射的表面路径。通过连续采样散斑信号波形中的强度变化次数，利用SM-LD中散斑信号的这种特性来检测目标表面的前沿和后沿。一旦确定了边缘，就可以轻松计算出表面的速度和长度。对于长度为60毫米、速度为200毫米/秒的均匀粗糙平面目标，长度和速度测量的误差分别可低至2.1%和1.75%。
