| 摘要 |
<p>A method and apparatus are provided for analyzing a light pattern produced on a photodetector array wherein a signal from the array is filtered by a low pass filter and then differentiated by at least one differentiator to obtain the first or second derivative of a point or points in the pattern. A zero crossing detector detects the point of zero crossing in the differentiated signal and a timer times this point to obtain the position of the point(s) in the pattern. This technique can be used with back-lit illumination of edge images as well as with diffraction fringes and triangulation spots, among other uses. Further techniques using photodetector arrays are also disclosed.</p> |
