Offset noise cancellation in array image sensors

摘要

An integrated circuit active pixel image sensor comprises an array of active pixels having associated therewith one capacitor in each pixel column for storing a combined pixel output signal comprising an image signal and a fixed offset signal and another capacitor in each column for capturing another signal produced when the pixel is reset. The array may be read row-by-row. Each column includes a comparator and a data latch via which a digitized fixed offset corrected pixel output signal is obtained using a ramp voltage source and a digital count broadcaster provided in the sensor.