Image processing device and method for producing in real-time a digital image from a sequence of digital images

Image processing device for producing in real-time a digital composite image from a sequence of digital images recorded by a camera device, in particular an endoscopic camera device, the image processing device comprising a selecting unit, a key point detection unit, a transforming unit and a joining unit, wherein the key point detection unit comprises a filter configured for producing a filter response for the reference image and for producing a filter response for the further image, wherein the key point detection unit comprises a maximum detection unit configured for executing following steps separately for the filter response for the reference image and for the filter response for the further image, wherein a variable threshold is used: i) creating blocks by dividing the respective filter response, ii) calculating the variable threshold for each of the blocks, iii) discarding those blocks of the blocks from further consideration, in which the respective filter response at a reference point of the respective block is less than the respective variable threshold.