The characterization of light by its tristimulus coordinates is briefly reviewed. The vector-transformation properties of these coordinates are shown, and the interpretation of change of reference stimuli as a change ...
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The characterization of light by its tristimulus coordinates is briefly reviewed. The vector-transformation properties of these coordinates are shown, and the interpretation of change of reference stimuli as a change of basis in a 3-dimensional vector space is mentioned. The transformation coefficients are then examined as inner products, in a vector space over a basis of the order of the continuum. In this larger system, all possible sets of tristimulus coordinates are associated with a common 3-dimensional subspace. The vector analogy is thereby extended and a generalization is made from tristimulus coordinates to systems based on any number of arbitrary weighting functions. Each such system has an associated subspace, of the appropriate number of dimensions (not necessarily 3), not necessarily significant for human vision. Applications to spectrum characterization and electro-optical detector–response estimation are given.
The resolution of images formed from turbulence-degraded lensless Fourier-transform holograms is analyzed for gaussian and exponential refractive-index structure function models, first by a geometrical-optics method a...
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The resolution of images formed from turbulence-degraded lensless Fourier-transform holograms is analyzed for gaussian and exponential refractive-index structure function models, first by a geometrical-optics method and then by Schmeltzer’s series-expansion method, under the assumption that the random log-amplitude and phase perturbations across the entrance pupil of the recording apparatus are locally stationary processes with gaussian statistics. Both long and short exposures are *** resolution of turbulence-degraded holographic images is governed primarily by a function m 2 ( r 1 ), for which analytical expressions are derived and results of experimental measurements are given. The analytical results obtained for m 2 ( r 1 ) by the geometrical-optics method are identical with those obtained by Schmeltzer’s series-expansion method. The measurements were made by an interferometric technique for horizontal atmospheric propagation paths of 86 and 542 m. In addition, holographic images of an extended object were obtained for the 86-m path.
From the Tower of Babel down to the present, man has been conscious of the limitations of language for conveying his thoughts to his fellows. One has only to use a term such as "artistic" or "intelligen...
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From the Tower of Babel down to the present, man has been conscious of the limitations of language for conveying his thoughts to his fellows. One has only to use a term such as "artistic" or "intelligent" in order to observe the varied meanings that different individuals attach to words.
Hues perceived in two-primary projections were predicted for all combinations of pairs of 31 different spectral primaries by use of our computerized version of the Helson–Judd formulation. The computer was instructed...
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Hues perceived in two-primary projections were predicted for all combinations of pairs of 31 different spectral primaries by use of our computerized version of the Helson–Judd formulation. The computer was instructed to note the absence from the predicted hues of any of the full possible complement of red, yellow–red, yellow, green–yellow, green, blue–green, blue, and red–blue. Experimental confirmation of the computations is reported, based on color naming by trained subjects of the cells in computer-generated quilts projected with a selection of near-spectral primaries. The results of these investigations confirm the usefulness of the Helson–Judd formulation as a means of translating from chromaticity to perceived color in colored displays.
When colorimetric specifications of a large number of samples need be computed from spectrophotometric data, an important saving of time can be realized by use of standard IBM punched-card computing equipment. The met...
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When colorimetric specifications of a large number of samples need be computed from spectrophotometric data, an important saving of time can be realized by use of standard IBM punched-card computing equipment. The method employs weighted ordinates, and results for two light sources can be obtained with very little more expenditure of time than for one. The method is described, with detailed instructions for the machine operators.
Electrical responses of the human retina were measured by an electrode mounted on a contact lens. The form and magnitude of such responses were detd. for stimulation by filtered lights having various dominant waveleng...
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Electrical responses of the human retina were measured by an electrode mounted on a contact lens. The form and magnitude of such responses were detd. for stimulation by filtered lights having various dominant wavelengths. Two sets of spectral sensitivity data, one for the dark-adapted eye and the other for the light-adapted, were obtained by computing the intensity of stimulation necessary at each wave-length to arouse an electrical response of a given small magnitude. Comparable data were obtained in psychophysical expts. in which the same filter combinations and closely similar methods of computation have been employed. The electrical data, for both the light-adapted and the dark-adapteded eye, agree much more closely with the psychophysically determined scotopic sensitivity curve than with the photopic. It appears, however, that lights of the shorter wave lengths are somewhat more effective in arousing electrical responses than the scotopic sensitivity curve would predict,.
Formulas expressing colorimetric purity in terms of given trilinear coördinates have been independently derived by Ives and Priest. This paper gives (1) the derivation of still another form of purity formula; (2)...
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Formulas expressing colorimetric purity in terms of given trilinear coördinates have been independently derived by Ives and Priest. This paper gives (1) the derivation of still another form of purity formula; (2) a discussion of the computational methods which are, at once, accurate and speedy, together with an analysis of the various formulas with regard to convenience for routine computing; (3) the extension of the new formulas to purity for purples; and, (4) a general solution for the trilinear coördinates ( r,g,b ) of a color of purity, p , in terms of the coördinates ( R,G,B ) of the spectrum and the luminosity coefficients ( L r , L g , L b ).
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