Patent ID: 6018365
Filing Date: 2000-01-25
Classification: H01L,H04N

Abstract:
A method for operating an imaging system having a plurality of active pixel sensor cells, the method comprising the steps of:resetting each of the active pixel sensor cells;collecting photons in each of the active pixel sensor cells during an integration period that begins after the cells have been reset;calculating n collected photon values for each of the active pixel sensor cells for photons collected during the integration period, where n is an integer, each collected photon value indicating how many photons have been collected in a cell since the cell was last reset;comparing the first n-1 collected photon values of each of the active pixel sensor cells to a predetermined value;storing each collected photon value of the first n-1 collected photon values of each cell that is equal to or greater than the predetermined value as a stored value;resetting each active pixel sensor cell having a collected photon value of the first n-1 collected photon values that is equal to or greater than the predetermined value;combining the stored value and the nth collected photon value of each cell having a stored value to obtain a total value for each cell; andoutputting the total value of each cell having a total value, and the nth collected photon value of each remaining cell.