Color Vision Deficiency (CVD) affects our ability to distinguish colors. It can impact on a child's ability to learn, the ability to select two socks that match in color, the selection of clothing, purchasing fruits and vegetables, and even careers. The purpose of the Colorblind Simulator app is to provide educators, graphic designers, and everyone who works with individuals with CVD, a way to understand their world.
The Colorblind Simulator app for Android is a collection of simulation tools. It includes tools for images, text, Material Design colors, and any single RGB color. Currently, it is the only color blindness simulation toolbox available for Android.
We do not see RGB colors. Rather, the cone cells on the retina of the eye respond to different wavelengths of light. There are three different types of cones: long wavelength (red) cones, medium wavelength (green) cones, and short wavelength (blue) cones. The following diagram illustrates the LMS wavelengths.
Simulation processing is a memory intensive task, as the app processes each pixel in an image. Each pixel is transformed to its LMS color, color loss factors are applied, and then transformed ack to RGB. The application default is for dichromatic vision, which involves 100% less loss of one cone type. These conditions are protanopia (red), deuteranopia (green), and tritanopia (blue). The most common form of color blindness is deuteranopia. A far larger number of individuals are affected by anomalous trichromacy, which means that there is a partial loss of one of the cone types. The following graphic compares (from left to right) normal, protanopia, deuteranopia and tritanopia vision for a flower.
The above images assumed 100% loss, and used the linear model. The app offers two other models. The linear model, itself, is a variation of the Brettel-Vienot-Mollon (BVM) model. The Meyer-Greenberg-Wolfmaier-Wickline (MGWW) is an alternate model that produces slightly different results. The MGWW model was developed for color monitors. A fourth, grayscale model simulates monochromatic vision, a vary rare form of color vision deficiency.
The Colorblind Simulator app is not limited to processing example images, images from galleries, or the camera. The text activity provides a way to test background colors with various text colors. Along with transforming the colors, the text activity displays the W3C contrast ratio. While it is just a dream, it would be nice if this activity put an end to red text on a black background, and yellow text on a white background.
The material colors activity provides shows the impact of CVD on the standard Android design colors. This activity is also a good way to see the impact on groups of colors. The following screenshot illustrates what red colors look like to someone who has protanopia. The darker colors of red are much hard to distinguish.
The quick test app displays the conversion of any single color. You can just play with the scroll bars and watch the colors change.
To see these features in action, I created a two minute video at https://youtu.be/nblzVHEbu2s. The Colorblind Simulator Pro app is available from the Google Play store, and only costs $1.29, which helps support future development of this app. If you have any questions about this app, you can contact me through the Twitter link on this page, or send an email to support@all-things-android.com.
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