This paper describes a computational method for estimating the body reflectance function of color surfaces. The experimental apparatus consists of a vision system having seven spectral channels whose wavelength sensitivities cover the visible spectrum. The estimation of the spectral-reflectance function is based on finite-dimensional linear models. In order to use digitized imaged data to evaluate the surface reflectance, a procedure for bypassing the problem of unknown illuminant spectral-power distribution was devised. For the simple objects used (color checker charts), it is found that an accuracy greater than 97% can be achieved.