Hadamard encoding mask

R. A. DeVerse, R. M. Hammaker, and W.G. Fateley, An Improved Hadamard Encoding Mask for Multiplexed Raman Imaging Using Single Channel Detection, J. Mol. Struct, 521, 77-88 (2000). 

Fig. 37. Hadamard mask with a total of 13 slots for demonstration of the principle. Only 7 slots (within the section marked by the heavy line) are exposed to the radiation. 7 independent measurements are obtained by shifting the mask stepwise, each step corresponding to the width of 1 slot on the mask. The resulting Hadamard encoding matrix is a 7 X 7 cyclic matrix...

In the most mature design, one spatial dimension of the magnified Raman image was encoded using a linear Hadamard transform mask. The second spatial dimension was projected unaltered until it was compressed in one dimension using a cylindrical lens and... 

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