Patent ID: 8248479

Claim:
An image processing apparatus for processing output pixel data from a scanned, two-dimensional imaging array having an output intensity function I(x k ,y j ), the apparatus comprising: means for evaluating an Nth order polynomial intensity function G(x k ,y j ), where I(x k ,y j ) comprises an irregular surface consisting of target and background data superimposed on a bias approximating to a smooth surface represented by G(x k ,y j ), said evaluating means including an adder adapted to determine the intensity function G(x k ,y j ) for a given point by adding the value of the intensity function G(x k-1 ,y j-1 ) of a previously calculated point to an offset value; means for calculating coefficients of the intensity function G(x k ,y j ) from the output intensity function I(x k ,y j ); means for subtracting G(x k ,y j ) from I(x k ,y j ); and means for outputting unbiased target and background video data based on a result of the subtracting means.