Luminance mapping of light sources using ray sampling and compression

In this paper, a ray sampling method for calculating the luminance maps of light sources and compressing the ray files is proposed. The approach can directly derive luminance maps ofa light source from the ray file. The Fibonacci lattice model and the Kriging techniques are used to reconstruct the rays and to interpolate the luminous flux values of the new rays from the original ray data, respectively. A planar LED is used for the verification experiments. Luminance maps are simulated via sampling a ray file of the LED, and compared with actually measured luminance maps. A good agreement is found by high NCC and low NRMSE values as wellas the visual comparisons,and indicates the effectiveness of the proposed method. In addition, the ray emission experiments are performed,and the experimental results preliminarily validate the ability of the proposed sampling method in terms of compressing ray data.