1. A system for determining a time response to a monotonically changing characteristic of a sample, comprising: a camera that obtains a plurality of images of the sample over time, each image having a plurality of pixels, each pixel having an amplitude corresponding to the monotonically changing characteristic of the sample; and a processor that receives the plurality of images and generates a data array for at least a portion of the plurality of pixels, the data array corresponding to a logarithm of the pixel amplitude at a given time and a logarithm of the given time, wherein the processor fits a polynomial to at least a portion of the data array, the polynomial having at least one polynomial coefficient, such that each pixel in said portion of plurality of pixels is represented by a coefficient array containing said at least one polynomial coefficient.