Preliminary Experiment for Spectral Reflectance Estimation of Human Iris using a Digital Camera June 8 2000

1) Goal – Perform preliminary experiment to check the feasibility and evaluate the accuracy of spectral estimation using a digital camera. 2) Background Multi-spectral acquisition and linear methods have been widely used to estimate spectral properties of imaged materials. 1 2 0 0 O , (1) and the object spectral reflectance as r=(r 1 , r 2 , ... r n) T , where the index indicates the set of n wavelengths over the visible range and T the transpose matrix, representing the transmittance characteristics of the m filters as columns of F (2) and the spectral sensitivity of the detector as 1 2 0 0 O , (3) then the captured image is given by D c =(DF) T Sr, where D c represents the digital counts, and the color vector can be represented as c=At=(X, Y, Z) T where X, Y, Z are the CIE tristimulus values. The CIELAB L*, a*, b* are given by the non-linear transformation ξ, where ξ(X, Y, Z) = L*, a*, b*. If the spectral reflectance is sampled in the range of 400 nm to 700 nm wavelength in 10 nm intervals we have 31 samples. Ideally we should have 31 signals to