Baranoski, Gladimir V.G.Rokne, Jon G.Xu, Guangwu2008-05-082008-05-081999-03-01http://hdl.handle.net/1880/46402Virtual spectrophotometric measurements have important applications in physically-based rendering. These measurements can be used to evaluate reflectance and transmittance models through comparisons with actual spectrophotometric measurements. Moreover, they can also be used to generate spectrophotometric data, which are dependent either on the wavelength or on the illuminating geometry of the incident radiation, from previously validated models. In this paper the ray casting based formulation for virtual spectrophotometers is discussed, and a mathematical bound, based on probability theory, is proposed to determine the number of rays needed to obtain asymptotically convergent readings. Specifically, the exponential Chebyshev inequality is introduced to determine the ray density required to obtain reflectance and transmittance measurements with a high reliability/cost ratio. Practical experiments are provided to illustrate the validity and usefulness of the proposed approach.EngComputer Scienceunknown1999-639-0210.11575/PRISM/30977