Patent ID: 6515702
Filing Date: 2003-02-04
Classification: H04N

Abstract:
A CMOS radiation-sensing device, comprising:a substrate formed of a semiconductor material; a detector array formed in said substrate and configured to have CMOS detector pixels to detect radiation by producing electrical signals indicating said radiation; a readout circuit having a plurality of storage cells formed in said substrate displaced from said detector array and connected to respectively receive said electrical signals from a group of pixels in said detector array in parallel to produce an output indicative of said radiation; and a pixel-selecting circuit formed in said substrate and configured to select a special pixel from said detector array which has a maximum pixel signal amplitude in a frame captured by said detector array, wherein said pixel-selecting circuit comprises an array of signal-processing circuits respectively connected to receive said electrical signals from said readout circuit in parallel, a ramp generator to produce a global ramp signal to said array of signal-processing circuits, an inhibitor circuit to permit a signal-processing circuit with a largest signal to output said largest signal and to inhibits other signal-processing circuits, a memory unit storing said largest signal value and an address of a corresponding pixel which produces said largest signal, and a comparator circuit to compare an existing signal in said memory unit with largest signals selected from other groups of pixels in said detector array to select said special pixel.