Searched for: subject:"Perception"
(1 - 9 of 9)
document
Walraven, P.L. (author), Instituut voor Zintuigfysiologie TNO (author)
On the basis of new experimental data of tritanopic vision the convergence centre for tritanopia has been redetermined, and has turned out to bex' = 0.1747,y' = 0.0060 in the Judd 1951-chromaticity diagram. A consequence of this determination is that the blue system is more sensitive than was concluded from the Thomson-Wright (1953) study. The...
article 1974
document
Walraven, J. (author), Instituut voor Zintuigfysiologie TNO (author)
article 1979
document
Vos, J.J. (author), Walraven, P.L. (author), Instituut voor Zintuigfysiologie TNO (author)
On the basis of the concepts, discussed in Part I of this study, a line element is developed to describe colour discrimination data. First the simple case of unsaturated neural data transmission is treated. Then complicating effects of saturation and supersaturation are introduced. The goodness of fit with shapes and orientation of JND-ellipses...
article 1972
document
Vos, J.J. (author), Estevez, O. (author), Walraven, P.L. (author), Instituut voor Zintuigfysiologie TNO (author)
New action spectra are derived for the foveal cones on the basis of three assumptions: (1) the Stiles-Burch (1959) colorimetric data are better than CIE 1931; (2) the long wavelength flanks of the dichromatic luminosity functions offer better anchorage than the confusion loci; and (3) the relative mutual heights per receptor can be derived from...
article 1990
document
Vos, J.J. (author), Walraven, P.L. (author), Instituut voor Zintuigfysiologie TNO (author)
To derive the fundamental response curves for the three colour mediating systems from the location of the dichromatic confusion centres, one must make certain assumptions on the nature of dichromatism. It is shown, however, that one can avoid to make specific quantitative assumptions by bringing into the picture other visual data, such as the...
article 1971
document
Walraven, J. (author), Janzen, P. (author)
In this investigation, carried out under a Youth Health Care postgraduate course in Nijmegen, the stereopsis of a school population of 730 children, aged 4-18 years, was recorded and clinically evaluated. Stereopsis was measured using the TNO test, a random-dot stereo test especially designed for the early detection of amblyopia. The main aims...
article 1993
document
Bouman, M.A. (author), Walraven, P.L. (author), Instituut voor Zintuigfysiologie TNO (author)
On the basis of measurements of the achromatic zone for red light in the fovea and for green light in the periphery, a discussion is given on the possible difference in threshold mechanisms for the achromatic (scotopic) and chromatic (photopic) retinal systems. A specific suggestion for this distinction is given that not directly refers to the...
article 1972
document
Walraven, J. (author), Werner, J.S. (author)
The locus of unique white was measured for two observers over a wide range of stimulus intensities, using both direct matching and absolute judgements. Chromaticity coordinates of each observer's unique white were found to be invariant over a range of about 4 log units. This result is discussed in the context of the class of models that explain...
article 1991
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Dijk, J. (author), Verbeek, P.W. (author), Walraven, J. (author), Young, I.T. (author)
We present the results of experiments in which we manipulated color images in the CIELAB space by first applying a scaling factor on chroma (C*). After this we applied a gamma transformation (an exponent relating the input to the output) to the luminance (Y) in XYZ space, while keeping the chromaticity values (x, y) constant. The aim of the...
conference paper 2002
Searched for: subject:"Perception"
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