Patent ID: 8115824

Claim:
Active-Pixel-Sensor apparatus for use in a star tracker device, the active-pixel-sensor comprising: an imager chip, said imager chip configured with an array of photo-diodes configured to operate as optical pixels, and a logic circuit being configured for: reading out a pixel signal depending on an amount of light irradiated during a predetermined integration time and resetting the optical pixel upon termination of the predetermined integration time; processing the pixel signals and to output the modified signals; and periodically performing a non-destructive readout of the pixel signal during the integration time, wherein the logic circuit is further configured for: detecting whether or not a discontinuity has occurred in the pixel signal during the integration time, and for modifying the signal depending on the result of this detection; and wherein the logic circuit is further configured to: determine a difference between results of subsequent non-destructive readouts, and detect the discontinuity by comparing the thus determined difference with a predetermined threshold value.