| 摘要 |
<p>A method for obtaining a reflectance function from a camera output includes the following steps: uniformly sampling the visible range of wavelengths (λ = a to λ = b) by choosing an integer n and specifying that λi =a+(i-l)Δλ, i =1,2,...n, with formula (I); defining a relationship between camera output and reflectance function, using the following equation: P = WTr, where P is a known camera response vector, W is a known weight matrix derived from an illuminant function and the spectral sensitivities of the camera sensors, WT is the transposition of the matrix W and r is an unknown n component column vector representing reflectance function defined by formula (II): where R(λ1)to R(λn) are the unknown reflectances of the observed object at each of the n different wavelengths; and finding a solution for P = WTr which includes a measure of both the smoothness and the colour constancy of the reflectance function, the relative importance of smoothness and of colour constancy being defined by respective weighting factors. The above method results in a reflectance function which is relatively smooth and which preferably has a high degree of colour constancy, and is therefore realistic.</p> |
