A space-variant differential operator for visual sensitivity.
All the elements of a Fourier analysis can be derived from the experiments of Graham and Robson on contrast sensitivity. Once their experiment is posed as an eigenvalue problem, a complete orthonormal set of eigenfunctions results from solving the associated differential equation. Neither sine and cosine nor Gabor functions result. Instead, the Hermite functions arise as the eigenfunctions of a space-variant differential operator used to model the contrast sensitivity of human observers. These functions, up to a constant, are their own Fourier transforms, and in principle can be used to exactly represent the Fourier transform of naturally occurring visual images.
Stewart
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AL
Stevens Institute of Technology, Hoboken, NJ 07030.
Pinkham
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D015350:Contrast Sensitivity / Q000502:physiology*; D003491:Cybernetics; D005583:Fourier Analysis; D006801:Humans; D008960:Models, Psychological