The Effects of Digital Cameras Optics and Electronics for Material Acquisition

For material acquisition, we use digital cameras and process the pictures. We usually treat the cameras as perfect pinhole cameras, with each pixel providing a point sample of the incoming signal. In this paper, we study the impact of camera optical and electronic systems. Optical system effects are modelled by the Modulation Transfer Function (MTF). Electronic System effects are modelled by the Pixel Response Function (PRF). The former is convolved with the incoming signal, the latter is multiplied with it. We provide a model for both effects, and study their impact on the measured signal. For high frequency incoming signals, the convolution results in a significant decrease in measured intensity, especially at grazing angles. We show this model explains the strange behaviour observed in the MERL BRDF database at grazing angles.