Search results for "Standard illuminant"
showing 3 items of 13 documents
Electromagnetic spectrum and color vision
2004
In most of occasions the maps, drawings and printed images are elaborated thinking that the observer will visualize them with illuminants like the light of the day. With these illuminants, for example the CIE D/sub 65/, we can distinguish the great quantity of colors that it is capable the human eye. But if the illuminant has a very different spectrum than the light of day, for example the light of acetylene, the number of colors that we are able to distinguish can decrease drastically.
Multispectral analysis of color vision deficiency tests
2011
Color deficiency tests are usually produced by means of polygraphy technologies and help to diagnose the type and severity of the color deficiencies. Due to different factors, as lighting conditions or age of the test, standard characteristics of these tests fail, thus not allowing diagnosing unambiguously the degree of different color deficiency. Multispectral camera was used to acquire the spectral images of the Ishihara and Rabkin pseudoisochromatic plates in the visible spectrum. Spectral data was converted to cone signals, and successive mathematics applied to provide a simple simulation of the test performance. Colorimetric data of the each pixel of the test image can be calculated an…
Color discrimination under mesopic conditions in cats and humans
1995
The ability to discriminate colors under various levels of mesopic illumination was studied in three cats using colored papers as stimuli and with a computer controlled training schedule. Discrimination based on brightness differences was prevented using a new method in which illuminant color was varied. The luminance threshold for color discrimination in cats was found to be 0.5 cd/m2, close to the cone threshold reported by others from ganglion cell recordings. The same experiment was carried out with human subjects and revealed a luminance threshold of 0.00042 cd/m2 for color discrimination.