An exposure pattern is computed which is used for exposing a desired pattern on a target by means of a particle beam and a blanking aperture array in a particle-optical lithography apparatus, taking into account a non-uniform current dose distribution as generated by the beam over the positions of the apertures of the blanking aperture array: From the desired pattern a nominal exposure pattern is calculated as a raster graphics comprising nominal dose values for the pixels of the raster graphics; based on a map of the current dose distribution, which correlates each aperture with a current factor describing the current dose of the beam at the location of the aperture, a compensated dose value is calculated for each pixel; and for each pixel, a discrete value is determined by selecting a value from a discrete gray scale so as to approximate the compensated dose value.