1. A camera system ( 10 ) for generating an image presegmented into regions ( 106 a - b ) of interest and of no interest, comprising: an image sensor ( 18 ) for taking a raw image resolved into pixels and an evaluation unit ( 20 ) configured to divide the raw image into part regions ( 106 a - b ), configured to calculate a respective contrast value for each part region ( 106 a - b ) and configured to decide whether each part region ( 106 a - b ) is either a region of interest ( 106 a ) or a region of no interest ( 106 b ) based on the respective contrast value, wherein the evaluation unit ( 20 ) has a preprocessing unit ( 22 ), which is implemented on an FPGA, configured to access the respective pixels of a part region ( 106 a - b ) and configured to generate respective summed values (a, b) for the part region based on the respective pixels; and wherein the evaluation unit further has a structure recognition unit ( 24 ) configured to calculate the respective contrast value for the part region ( 106 a - b ) based on the respective summed values (a, b) without accessing the respective pixels.