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Biomedical subjects

C W McCutchen

Publications and source records attributed to C W McCutchen.

6 recordsLinked to original sources
PubMed1991

Convolution relation within the three-dimensional diffraction image.

The amplitude in the image of a point source is (a constant times) the three-dimensional Fourier transform of the lens pupil, i.e., of the amplitude distribution of the converging waves in angle space. If the three-dimensional pupil has axial symmetry, it can be factored into a spherical shell and a one-dimensional function of distance along the axis. The amplitude in the image is given by the convolution of the Fourier transforms of the factors. On the axis, the amplitude is the Fourier transform of the one-dimensional function. Therefore the amplitude anywhere in the image is the convolution of the amplitude on the axis and the Fourier transform of the spherical shell.

Fourier Analysis↗
PubMed1976

Flow visualization with stereo shadowgraphs of stratified fluid.

Water stratified thermally or with dissolved material has a refractive index that varies with height. The stratification has no obvious visual effect until the fluid is disturbed, for example by a fish, but then it marks the creature's wake with a jump in refractive index that is visible in shadowgraphic projection. Two shadowgraphs in stereo display the wake in three dimensions. For a permanent record, or for analysing events too quick for the eye to follow, movies can be taken of the shadowgraphs.

Animals↗