1. A processor readable storage media that includes executable data, wherein the execution of the data enables actions for correcting a digital signal from an image sensor for intensity variations across an optical field imaged onto the image sensor by an optical system, wherein the image sensor includes a multi-dimensional array of individual photo-detectors, the actions comprising: maintaining image correction data for each of at least two color components of the optical field as a function of a radius from a determined point in the optical field imaged thereon to enable spherical correction of the digital signal of the imaged optical field; determining a radius for individual current photo-detectors from a distance along a scanned pattern between the current photo-detector and a prior photo-detector for which its radius is known; utilizing the determined radius to access the intensity corrections for one of the at least two color components of the present photo-detector from the maintained set of intensity correction data; and combining the intensity corrections for the current photo-detector with the image sensor's digital signal for the current photo-detector to provide correction to an outputted digital signal.