Patent ID: 6198086
Filing Date: 2001-03-06
Classification: H04N

Abstract:
A method for detecting an image signal by means of an array of photosensitive devices with each of which the charge of a capacitance can be altered, comprising the following steps:a) detecting an optical signal of each photosensitive device by means of the following substeps:a1) creating a charge condition of the capacitance with a predetermined voltage,a2) changing the charge of the capacitance either with a photocurrent generated in the photosensitive device by the optical signal or with a quantity derived from the same and detecting the voltage across the capacitance after a predetermined time period,a3) deciding whether the detected voltage lies within a valid range and, if this is so, determining on the basis of the detected voltage a valid signal which characterizes the detected optical signal, and, if this is not so,a4) repeating the steps a1) to a3) with a time period which differs from the predetermined time period either a predetermined number of times or until it is determined in step a3) that the detected voltage lies in a valid range;b) storing the valid signal, determined for each photosensitive device and characterizing the detected optical signal, together with the time period for which a valid signal has been detected, wherein a predetermined signal is stored if a valid signal characterizing the detected optical signal is not detected in steps a1) to a4); andc) obtaining the image signal from the stored optical signals for the individual photosensitive devices and the respective assigned time periods.