row drivers 40 charge signals stored in the selected row of pixels are provided to a readout circuit 42 the pixels read from each of the columns then can be read out sequentially using a horizontal addressing circuit 44 differential pixel signals vout1 vout2 can be provided at the output of the readout circuit 42 as shown in fig2 the array 30 includes multiple columns 49 of cmos active pixel sensors 50 each column includes multiple rows of sensors 50 signals from the active pixel sensors 50 in a particular column can be read out to a readout circuit 52 associated with that column signals stored in the readout circuits 52 then can be transferred to an output stage 54 which may be common to the entire array of pixels 30 the analog output signals then are sent for example to a differential analog to digital converter adc as illustrated in fig3 each cmos active pixel sensor 50 includes a photo sensitive element such as a photodiode 60 buffered by a source follower n channel mos transistor m 2 the pixel has an integration capacitance c in and includes a reset switch that can be implemented as an n channel mos.