Patent ID: 9590000
Date: 2017-03-07
CPC Classifications: F41G,G01S,H01L

Claim:
1. A method of imaging a field of view, the method comprising: illuminating the field of view by means of the output beam of a CW laser, modulated at a first rate to provide a stream of laser pulses; imaging the field of view using a multi-pixel sensor array; accumulating signals obtained from said pixels during the detection of laser pulses reflected from said field of view in a first set of pixel signal accumulators, for the duration of a predetermined plurality of pulses, to obtain from those pixels a first set of accumulated pixel signals arising from said reflected laser pulses; reading out said first set of accumulated pixel signals to image said field of view, after completion of said predetermined plurality of pulses; accumulating signals obtained from said pixels in periods between the detection of pulses reflected from said field of view, in a second set of pixel signal accumulators, for said duration of said predetermined plurality of pulses, to obtain from those pixels a second set of accumulated pixel signals; and reading out said second set of accumulated pixel signals after completion of said predetermined plurality of pulses, wherein said pixel signals accumulated in each of said first and second sets of pixel signal accumulators and read out therefrom, are subtracted, to generate image signals of said field of view in which the effect of background illumination is subtracted out.