Abstract: A device and a method for projecting image data onto a projection surface of a vehicle windowpane of a vehicle. An image data processing unit generates second image data from first image data based on recorded surroundings brightness of the vehicle. A gradation curve is used to generate the second image data in such a way that dark image regions of the first image data lying below a predetermined color brightness threshold compared to image regions lying above the color brightness threshold in the first image data are brightened in the second image data compared to the first image data with regard to color or greyscale spectra. A degree of brightening of the dark image regions in the first image data increases with an increase in the recorded surroundings brightness.