| 摘要 |
PROBLEM TO BE SOLVED: To provide a displacement detection method for estimating the sub- pixel displacement of an image in an image correlation position transducer with high speed and accuracy, and a reading head using it. SOLUTION: A correlation value (sum of differences) between first and second images is calculated and plotted each time one pixel is shifted along the direction of displacement. The points of a relatively small number of correlation values in the vicinity of extreme values are used. Also, symmetrical points across extreme values of the points of specific correlation values are obtained by interpolation from the points of other correlation values, and mid-point positions with respect to these points are used as extreme values. Thus, the speckle image correlation position transducer can be formed which can detect displacement with high speed and accuracy through simple calculations, using the points of a relatively small number of correlation values.
|
