Improved shading model in spectral-based ray tracing method

This paper proposes an improved ray tracing technique that can reproduce a realistic image based on the spectral characteristic of real lights and objects. The proposed algorithm is able to generate a realistic image that simulates the physical quantity of light energy incoming toward a viewer. First, an accurate image is reproduced using the backward ray tracing method and by tracing the spectral transformation procedures of the rays using the spectral characteristic of objects and illuminants. Next, the shading model of the reproduction algorithm of a realistic image is improved by applying Bouguer-Beer's law to consider the optical absorptive property of transparent objects. Finally, a new ambient light term that considers the diffuse reflection of neighboring objects is defined instead of a constant ambient light term.