An image processing method for detecting the activation of brake lights of vehicles driving in front, which do not emit an additional or a changed modulated signal during the braking procedure, has been presented. For this purpose, an image sensor or an image sensor system is aligned to a point in front of the vehicle, the camera images are fed into a memory and a motor vehicle driving in front is identified by means of a pattern recognition method on the image; in addition, following the detection of the vehicle, image areas are determined which contain brake lights to a high degree of probability.