测量比的标定方法分析与应用

标定是视觉测量的首要环节,标定结果的精度及算法的性能影响测量结果,在机械零件的尺寸测量中,普遍采用标定测量比的方法进行测量.经过缜密地推导,得出了测量比的计算公式,给出了严格的测量比定义.根据新的定义,必须保证零件到相机的距离和标定件到相机的距离严格相等,否则测量结果毫无意义.以空间两点高程差测量为例,给出了用测量比法进行尺寸测量的详细过程,可作为修正由于零件到相机距离变化而引起的测量误差的参考.

Analysis and Application of Calibration Method of Measurement Scale

Calibration is the initial step in vision measurement,and its accuracy and algorithm performance affect measurement results.Measurement scale is widely used in measuring mechanical parts size.A formula used for the calculation is worked out through rigorous deducion,and measurement scale is then rigorously defined.According to the new definition,it is crucial that the distance between parts and camera should be precisely the same as that between calibration parts and camera.Otherwise,the results count for nothing.The depth displacement of two points at ransom,for instance,is calculated in detail by adopting measurement scale,providing implication for correcting measurement errors due to variation of distance between parts and camera.