Patent ID: 8363140

Claim:
A digital vision sensor which comprises an array of pixels each having a photodetector and adapted to receive a light beam representing a visual scene, comprising: a reference voltage V ref generator; in each pixel, means for generating during an integration phase, a voltage V P proportional to illumination received by the pixel; in each pixel, a comparator for determining the instant at which the voltage V P of said pixel reaches the voltage V ref , common to all the pixels; a clock generator generating a clock; a device for counting a number of periods of the clock having elapsed since the beginning of the integration phase, delivering a result as a binary code; one RAM static memory word per pixel; in each pixel, means for allowing said binary code present at said instant to be written into said memory; means for controlling a termination of the integration phase; means for reading information stored in the memory; and means for computing the contrast from binary values stored in memory, wherein the period of said clock proportionally increases with the elapsed time from the beginning of the integration phase, and wherein a termination phase for ending the integration phase preceding resetting to zero of the pixels, is carried out with a fixed frequency clock while the reference voltage V ref satisfies a relationship: V ref = 10 - i_i ramp K α ⁢ V ref ⁢ ⁢ 0 .