Multiple illuminants

The gray world assumption works nicely if we only have a single illuminant. However, if we have multiple illuminants, then the gray world assumption does not work. We can see this in image (b) of Figure 6.4. This is not surprising, as one of the assumptions was that we... 

Figure 6.10 Results obtained using a simplified version of Horn s algorithm. It is assumed that the illuminant is constant across the entire image. The algorithm cannot be used if multiple illuminants are present.

Figure 6.16 Results obtained using Forsyth s gamut-constraint algorithm. The algorithm assumes a single illuminant for the entire image, so we cannot use this algorithm if multiple illuminants are present. For both images, the RGB cube was assumed to be the canonical gamut.

Figure 6.24 Results obtained with color cluster rotation. The algorithm performs well given a uniform illumination. It is not able to handle images with multiple illuminants.

The Perkin Elmer FT-IR microscope features compact Cassegrain optics, fixed stereo, zoom stereo, and video viewing points, a vernier calibrated sample stage, multiple illumination positions, high sensitivity, reproducibility, and ease of operation. 

The intensity differences obtained in the diffraction pattern by illuminating such a crystal by x-rays of different wavelengths can be used in a way similar to the method of multiple isomorphous replacement to obtain the phases of the diffracted beams. This method of phase determination which is called Multiwavelength Anomalous Diffraction, MAD, and which was pioneered by Wayne Hendrickson at Columbia University, US, is now increasingly used by protein cystallographers. 

An alternative and illuminating explanation of reduced rank regression is through a principal component analysis of Y, the set of fitted F-variables resulting from an unrestricted multivariate multiple regression. This interpretation reveals the two least-squares approximations involved projection (regression) of Y onto X, followed by a further projection (PCA) onto a lower dimensional subspace. 

For current densities below JPS the photocurrent in aqueous HF is found to be increased by a factor of 2 or even up to a factor of 4 for small photocurrent densities [Br2, Mai, Pel]. This effect is shown in Fig. 4.13. For non-aqueous HF electrolytes factors between 2 and 3 are observed. For further reduction of the illumination intensity the multiplication factor approaches infinity, because of the illu-... 

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