The hypothesis of this study was to find out whether it is possible to capture Woelfflin's basic concepts using methods within CBIR for estimating global characteristics of art works. If results from regression analysis of behavioral data can be linked to global spectral and spatial characteristics of the same art works, then this would substantiate our hypothesis. From a regression analysis assuming a linear relationship between trained observers' ratings of art works representing Woelfflin's concepts and three global image processing features commonly used in CBIR and assumed to be significantly related to the same concepts, we found results that give support to our hypothesis - it seems possible to grasp some of the art concepts by CBIR methods.
This paper will present a literature survey on the basic aspects of the possibilities for color presentation in the
peripheral visual field and the results from some experiments from two laboratories in Japan and in Sweden. The
method used was a color naming technique that included hue and saturation/chromaticness estimations of color
stimuli of different eccentricity. In one laboratory, the size effect was also examined. Unique hue components of
the stimuli were derived from the results of hue and saturation/chromaticness estimates. The results from the two
laboratories showed similar tendency despite the differences in the experiments. The results showed that an
increase of the retinal temporal eccentricity to 40 deg caused impaired color appearance especially for red and
green colors. Smaller color stimuli, subtending 2 deg of visual angle, were perceived as less chromatic as larger
color stimuli, subtending 6.5 deg of visual angle. The results are in line with some earlier studies showing that
blue and yellow colors are better perceived than green and red in periphery.
Three color schemes (monochrome, dichrome, and polychrome) based on basic principles for color perception and cognition were optimized and applied to an electronic map in a horizontal-situation display. Principles for color discrimination, symbol coding, and color naming were applied for the super-imposed symbols (targets, waypoints etc) and for the map symbology (land, water, roads). The color codes were tested in a visual search and detection experiment in a real-time simulation in an air-to-air mission with test pilots as subjects. The simulation task was as close as possible to a real-life situation. The pilots had to track a maneuvering target within specific limits. Reaction times for target detection were recorded. After the simulation, the test pilots gave a subjective estimation of the different color schemes. They also estimated them according to situation awareness using a rating technique on cognitive compatibility (CC-SART). All the results, both the objective and the subjective show that color schemes are advantageous in comparison to the monochrome code. The reaction times were significantly lower for the chromatic color codes. The estimated situation awareness was higher for the chromatic schemes and the subjects gave higher preferences to the chromatic codes.
This report surveys cognitive aspects of color in terms of behavioral, neuropsychological, and neurophysiological data. Color is usually defined as psychophysical color or as perceived color. Behavioral data on categorical color perception, absolute judgement of colors, color coding, visual search, and visual awareness refer to the more cognitive aspects of color. These are of major importance in visual synthesis and spatial organization, as already shown by the Gestalt psychologists. Neuropsychological and neurophysiological findings provide evidence for an interrelation between cognitive color and spatial organization. Color also enhances planning strategies, as has been shown by studies on color and eye movements. Memory colors and the color- language connections in the brain also belong among the cognitive aspects of color.
Used as a redundant code, color is shown to be advantageous in visual search tasks. It enhances attention, detection, and recall of information. Neuropsychological and neurophysiological findings have shown color and spatial perception to be interrelated functions. Studies on eye movements show that colored symbols are easier to detect and that eye fixations are more correctly directed to color-coded symbols. Usually between 5 and 15 colors have been found useful in classification tasks, but this umber can be increased to between 20 to 30 by careful selection of colors, and by a subject's practice with the identification task and familiarity with the particular colors. Recent neurophysiological findings concerning the language-concept connection in color suggest that color concept retrieval would be enhanced by free color naming or by the use of natural associations between color concepts and color words. To test this hypothesis, we had subjects give their own free associations to a set of 35 colors presented on a display. They were able to identify as many as 30 colors without training.
The increasing research and debate during the last decade on the use of color as an information code indicates that color displays are here to stay—because they are preferred to monochrome displays and because they are generally more effective, provided the color coding is done properly.
Depending on the function of the colors, the requirements for legibility, color differences, color contrasts, and color appearance may be widely different.
To meet design requirements for video display units (VDUs), perceptually based color spaces are needed. During the last decade color appearance systems have come into use for color selection in color VDUs. These systems are gaining prominence over colors defined in numerical RGB values, which are not related to the perceptually relevant dimensions of hue, chroma (chromaticness, saturation), lightness, and blackness. We have developed a 'Palette' based on the Natural Color System (NCS) and on the CIE 1976 (L* u* v* ) system (CIELUV). With the 'Palette', colors can be selected interactively as well as automatically, according to a) NCS notations and/or CIELUV values, b) every day language or, c) the functional significance of the color in the image. A palette is presented in a frame around the image. The user is then free to try the different colors one at a time at his/her convenience.