초록 ▼

A method and apparatus are provided for analyzing the light pattern produced on a photodetector array. The signal produced by the array is filtered with a low pass filter and the output of the filter is differentiated to obtain either the first or second derivative of the filtered signal for one or

A method and apparatus are provided for analyzing the light pattern produced on a photodetector array. The signal produced by the array is filtered with a low pass filter and the output of the filter is differentiated to obtain either the first or second derivative of the filtered signal for one or more points in the pattern. The zero crossing of the differentiated signal is detected and the zero crossing point is timed relative to a further point, e.g., the start of the scan of the array, so as to obtain an output related to the position of the corresponding point or points in the pattern.

대표청구항 ▼

Method for analyzing a light pattern produced on a photo detector array, comprising the steps of: filtering the signal from said photodetector array with a low pass filter, differentiating the output of the low pass filter to obtain a derivative of said filtered signal at at least one point in said

Method for analyzing a light pattern produced on a photo detector array, comprising the steps of: filtering the signal from said photodetector array with a low pass filter, differentiating the output of the low pass filter to obtain a derivative of said filtered signal at at least one point in said pattern, detecting the point of zero crossing of said differentiated signal, and timing said zero crossing point relative to a reference point to obtain the position of at least one point.