Patent ID: 8823800

Claim:
A method for correcting non-uniform sensitivity of detector elements in a thermographic camera comprising: recording background frames for internal reference during shutter states corresponding to a beam path of the thermographic camera being closed, wherein a background frame comprises a data set of intensity values of individual detector elements associated with an image of said internal reference at a readout time, logging variations between the background frames for the shutter states, generating an updated background frame, using background frames recorded during at least two shutter states, from a newly recorded background frame and a background frame to be updated by adding a value of each pixel of the newly recorded background frame multiplied by a first factor and a value of each pixel of the background frame to be updated multiplied by a second factor, wherein the first factor is a value between zero and one, and the second factor is the difference between one and the first factor, so that a value of each pixel of the updated background frame is an accumulated weighted average, and correcting at least one image frame using the updated background frame.