Patent ID: 7920248

Claim:
Method for the optoelectronic contactless range measurement according to the transit time principle, in which a distance of an object from a sensor unit is determined from a time difference between a starting signal and an echo signal, which is derived from an optical measurement pulse reflected by the object and for determining the time difference the following steps are performed: a) by comparing the starting signal and echo signal with a digital clock a digital raw value is obtained, b) with the aid of at least two fine interpolators an initial time difference between the starting signal and the beginning of the digital raw value as well as a final time difference between the echo signal and the end of the digital raw value is determined, c) the fine interpolators are in each case supplied with analog signals corresponding to the initial time difference or final time difference, respectively, and are converted to a digital initial time difference or digital final time difference, respectively, wherein for the automatic calibration of the fine interpolators a plurality of measurements of the time difference between a starting signal and an echo signal are carried out according to steps a) to c), where the time intervals to be measured having no phase correlation with the digital clock and where, assuming an equal distribution for the probability with which the values in a given value interval for the initial time difference and final time difference are measured, corrections are calculated for at least one of nonlinearities and drifts of the characteristics of the fine interpolators.