1. Field
The present invention relates generally to color blind systems and more particularly to filtering graphics to enable color-blind viewing.
2. Background Information
Computer graphics systems are commonly used for displaying graphical representations of objects on a two-dimensional video display screen. Current computer graphics systems provide highly detailed representations and are used in a variety of applications. Such systems typically come pre-installed with a plethora of accessibility tools for people with disabilities. Yet, providing color corrected graphics for people who suffer from color blindness still remains a challenge.
More than 20 million Americans, many of them computer users, experience some form of color blindness, which is the inability to distinguish certain colors. When light enters the eye, it passes through several structures before striking the light sensitive receptors in the retina at the back of the eye. These receptors are called rods and cones. Rod are responsible for night vision, and cones are responsible for color vision, functioning best under daylight conditions.
Each of the three types of cones, red cones, blue cones and green cones, has a different range of light sensitivity. In an individual with normal color vision, the cone population consists of approximately 74 percent red cones, 10 percent green cones and 16 percent blue cones. The stimulation of cones in various combinations accounts for the perception of colors. For example, the perception of yellow results from a combination of inputs from green and red cones, and relatively little input from blue cones. If all three cones are stimulated, white is perceived as the color. Defects in color vision occur when one of the three-cone cell coding structures fails to function properly. One of the visual pigments may be functioning abnormally, or it may be absent altogether. Most color-deficient individuals have varieties of red or green deficiency.
Since most color-blind people see black and white accurately, color is not an issue if images are in grayscale. However, most applications and web sites are heavily color reliant. Color is a particular problem with image maps in which clickable areas are delineated by color. Application and website designers have attempted to address this problem by enhancing areas by placing underlined text or a black outline in the image. Another technique is to place colors against an appropriate background where they can be more visible. Furthermore, considering that most color-blind people have a red-green color blindness, limiting using red and green together is another option. However, this limits the palette of acceptable colors. Consequently, very few application and web developers are willing to sacrifice having a flashier site to accommodate color-blind users.
What is needed therefore is a method, apparatus and system for providing color corrected graphics for color-blind users.