Search results for "Chromaticity"
showing 4 items of 14 documents
Copper(I) Bromide: An Alternative Emitter for Blue-Colored Flame Pyrotechnics.
2015
Copper(I) bromide was evaluated as an alternative emitter for blue flame pyrotechnic compositions. CuBr and CuCl emission spectra were recorded from a butane torch flame and compared. Cu(BrO3 )2 was synthesized and used in pyrotechnic compositions as an oxidizer and the source for the generation of CuBr species. Pyrotechnic compositions, which contained copper and potassium bromates as oxidizers, were optimized for the generation of blue flames. The experimental data, including emission spectra of the flames, chromaticity coordinates, burning rates, luminous intensities, and sensitivity tests, were analyzed and compared.
Red-green flicker resolution as a function of heterochromatic luminous modulation.
1993
Critical fusion frequencies have been evaluated in heterochromatic red-green flicker as a function of red-green luminous modulation defined by mL = (R-G)/(R+G)%, at five different mean luminance levels, two test sizes (2 degrees and 5 degrees) and square wave stimuli. The extreme values mL = +/- 100 correspond to ordinary light-dark flicker (red or green); mL = 0 corresponds to pure chromatic flicker, and any other values correspond to simultaneous luminous and chromatic flicker. To implement the stimuli we have developed a new stimuli generator (AVICO, colour vision analyser) using bicolour LEDs as the light source and electronic control of the luminances and frequencies. The results for a…
ROBUST ROAD SIGNS SEGMENTATION IN COLOR IMAGES
2012
International audience; This paper presents an efficient method for road signs segmentation in color images. Color segmentation of road signs is a difficult task due to variations in the image acquisition conditions. Therefore, a color constancy algorithm is usually applied prior to segmentation, which increases the computation time. The proposed method is based on a log-chromaticity color space which shows good invariance properties to changing illumination. Thus, the method is simple and fast since it does not require color constancy algorithms. Experiments with a large dataset and comparison with other approaches, show the robustness and accuracy of the method in detecting road signs in …
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…