Abstract: A process for the automatic contrast and brightness control for thermal imaging apparatus of FLIR systems which is used for forming the actual value of the contrast and brightness of an evaluation window, fixing the shape of the evaluation window and displacing the position of the evaluation window in dependence on the content of the FLIR image, includes: utilizing "n" vertical image columns for evaluation of the FLIR image, converting the average brightness of the FLIR image into an analog voltage signal, comparing the analog voltage signal with a video signal of the FLIR image, summing the results of the comparison in the vertical image columns of the FLIR image such that a sum value results for each image column, determining the position of the horizon from the amounts of the sum values, and in the case of column sums that differ from each other, determining the optimum position of the evaluation window in the horizontal direction from the sum values of the columns such that the surface center of gravity o