A method of reducing column fixed pattern noise including calibrating a readout circuit, wherein the readout circuit is electrically connected to at least one programmable gain amplifier and an analog-to-digital converter. Calibrating the readout circuit includes electrically disconnecting the readout circuit from a pixel output and electrically connecting a pixel reset input of the readout circuit to a pixel output signal input of the readout circuit. Calibrating the readout circuit further includes comparing a measured output of the readout circuit to a predetermined value and storing the comparison result in a non-transitory computer readable medium. The method further includes operating the readout circuit, the operating the readout circuit includes receiving a pixel sample signal and outputting a calibrated output based on an operating output and the stored comparison result.