| abstract |
The more modern imaging systems employ solid state detector area arrays which "stare" at the viewed scene (and are thus known as "staring arrays") Unfortunately, these arrays are not very uniform, and the sensitivity and the output absolute value of the detector elements can vary significantly over the array. A normalisation process can be employed, but if such a process is based on the assumption that each element's output is a linear function of its input there may be problems. The present invention suggests a solution to this difficulty; it proposes dividing the operating range of the elements into a plurality of adjacent regions, calculating the gain and offset correction factors for each region separately (upon the basis that the input/output relationship in that region is linear), and then in operation correcting the element's output in accordance to which region it is in. <IMAGE> |