A medical image processing apparatus comprises processing circuitry configured to: obtain a medical imaging data set representative of at least part of at least one surface render from the medical imaging data set at least one image of the at least part of the at least one surface, wherein the or each image is rendered using a respective lighting configuration and determine a measure of lighting quality for the or each rendered image wherein, for the or each rendered image, the determining of the measure of lighting quality comprises, for each of a plurality of locations on the at least part of the at least one surface, determine a correspondence between a curvature of the at least one surface at that location and a lighting value at that location, wherein the lighting value is obtained from the rendering of the image and determine the measure of lighting quality based on the determined correspondences.
