System and method for calibrating a linear array using a calibration standard and a calibration piece with dark and light response measurements

Abstract

A method of balancing responses of a plurality of sensor chips arranged generally in a linear array comprising: exposing the plurality of sensor chips to an absence of illumination; measuring a dark response of each photosensor of a plurality of photosensors; positioning a calibration piece within a field of view of the plurality of sensor chips other than a calibration sensor chip; illuminating a calibration standard and the calibration piece with a light source; measuring a light response of each photosensor of the plurality of photosensors; applying an offset to the light response of each photosensor of the plurality of photosensors by subtracting the dark response of each photosensor of the plurality of photosensors to obtain an offset light response for each photosensor of the plurality of photosensors; calculating a mean offset light response for each sensor chip of the plurality of sensor chips by averaging the offset light response for each photosensor of the plurality of photosensors in each sensor chip of the plurality of sensor chips; calculating a modified light response for each photosensor of the plurality of photosensors by modifying the offset light response for each photosensor of the plurality of photosensors based on the mean offset light response of the sensor chip comprising the respective photosensor, the mean offset light response of the calibration sensor chip, an initial mean offset light response of the sensor chip comprising the respective photosensor, and an initial mean offset light response of the calibration sensor chip; and, applying a first gain to the offset light response of each photosensor of the plurality of photosensors based on the modified light response of each respective photosensor to obtain a corrected light response of each photosensor of the plurality of photosensors.