Abstract: To correct the gray levels or pixel intensities of images provided by a digital infrared camera having a two-dimensional array of detector elements with non-sensitive areas therebetween, correction coefficients respectively allocated to the detector elements are stored in a memory of an image processing system. The gray levels of image pixels are corrected by the respective corresponding correction coefficients. The correction coefficients are progressively updated and improved by means of a dynamic correction process. To distinguish stationary features in a scene being viewed from non-uniformities among the detector elements so that such stationary features do not influence the updating of the correction coefficients, the image of the scene incident on the detector is moved relative to the detector, by means of a microscanner deflecting the image beam incident, on the detector.

Abstract: The present invention relates to a multispectral photodiode for infrared radiation comprising a substrate, a first semiconductor layer of first conductivity with a large band gap arranged on the substrate, a second semiconductor layer of first conductivity with a small band gap arranged on the first semiconductor layer, a first diode area which is formed from a zone of second conductivity with the first semiconductor layer, and a second diode area which is formed from a zone of second conductivity with the second semiconductor layer. The disadvantage of known multispectral photodiodes is that the first diode area, which is sensitive to the short-wave portion, is smaller than the second diode area, which is sensitive to the long-wave portion.

Abstract: The invention concerns a process to correct the intensity of images from a digital infrared camera with a two-dimensional detector. First a stationary correction is made at a reference source to determine correction coefficients. For the stationary correction, an average intensity characteristic curve U.sub.av (T) is determined for the detector and compared with the intensity characteristic curve U.sub.j (T) for each image point j of the two-dimensional detector to determine correction coefficients for each image point j. A non-linear formulation is used to adapt the intensity characteristic curve U.sub.j (T) of each image point to the average intensity characteristic curve U.sub.av (T). Correction coefficients are stored in a memory to correct the individual intensity U.sub.j of each image point j during operation. During operation, the correction coefficients are improved dynamically. The intensity Uj of an image is recorded and the intensity Uj of the image is filtered by a locally acting adaptive filter.