1. A computer implemented method performed by a computer system programmed to perform the method comprising: determining by the computer system a first diffuse illumination compensation value associated with a first surface region on an object in response to an irradiance associated with the first surface region; determining by the computer system a first diffuse reflection value associated with the first surface region on the object in response to the irradiance associated with the first surface region; determining by the computer system a second diffuse illumination compensation value associated with a second surface region on the object in response to an irradiance associated with the second surface region; determining by the computer system a second diffuse reflection value associated with the second surface region on the object in response to the irradiance associated with the second surface region; receiving by the computer system a specification of a first weighting for the first diffuse illumination compensation value and the first diffuse reflection value, and a second weighting for the second diffuse illumination compensation value and the second diffuse reflection value, wherein the first weighting is different from the second weighting; determining by the computer system a diffuse illumination value associated with the first surface region on the object in response to the first diffuse illumination compensation value, the first diffuse reflection, and the first weighting; determining by the computer system a diffuse illumination value associated with the second surface region on the object in response to the second diffuse illumination compensation value, the second diffuse reflection, and the second weighting; and determining by the computer system an image including a rendered representation of the object in response to the diffuse illumination value associated with the first surface region and to the diffuse illumination value associated with the second surface region.