Exploring Haptic Colour Identification Aids
Richard Nguyen, Connor Geddes · 2019 · Proceedings of the 21st International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS) · doi:10.1145/3308561.3356111
Summary
This poster paper presents two novel haptic devices — ColourWrist and ColourVest — designed to help people with Colour Vision Deficiency (CVD) identify colors through tactile feedback. Approximately 8% of males and 0.5% of females have some form of CVD, which creates barriers in everyday tasks like selecting ripe fruit, reading color-coded maps and charts, choosing matching clothing, and interpreting traffic signals. Existing solutions include smartphone apps that identify colors visually or through speech, but these require looking at a phone screen — problematic when hands or eyes are busy. Previous haptic approaches used vibrotactile patterns on the palm but were slow to learn due to their complexity. ColourWrist is a wrist-worn device containing four solenoids and one vibration motor that maps any RGB color input to one of 16 color categories, each represented by a unique 2-second haptic pattern combining solenoid pushes and vibration. It connects to a smartphone camera that captures color data and transmits the corresponding pattern via Bluetooth. ColourVest is a vest-mounted system with a 10x8 2D vibrotactile array on the back that notifies the user of the general location of a user-selected target color within their field of view. The user selects one of 16 color categories they want to find, points the smartphone camera at a scene, and the vest buzzes in the corresponding back location where that color appears in the camera frame — enabling spatial color search without visual feedback.
Key findings
A preliminary evaluation with two participants with CVD (both protanopia — red-green color blindness) compared the devices against a control condition (no aid). Participants performed color identification tasks with physical objects and evaluated the devices qualitatively. Both participants described ColourWrist as "intuitive" and appreciated that the haptic patterns could be learned without visual reference. ColourVest was described as "useful" for locating specific colors in a scene, particularly for tasks like finding a colored object among others. The 16 color categories were derived by dividing the RGB color space into perceptually distinct groups. ColourWrist's haptic encoding uses combinations of the four solenoids (which produce distinct push sensations on different parts of the wrist) plus vibration intensity to create distinguishable patterns for each category. ColourVest's spatial mapping approach takes a fundamentally different strategy — rather than encoding color identity as a pattern, it maps color location to body location, leveraging the body's natural spatial perception. Limitations included the prototype's bulk, the need for further optimization of haptic patterns for discriminability, and the small participant sample.
Relevance
This research explores an underserved area of accessibility: assistive technology for color vision deficiency. While CVD affects a significant portion of the population, technological solutions have been limited primarily to visual overlays (color-correcting glasses) or smartphone apps that name colors on screen. Haptic approaches offer the unique advantage of being usable while the eyes and hands are engaged in other tasks — a limitation of both visual and speech-based color identification tools. The two devices represent complementary design philosophies: ColourWrist answers "what color is this?" through encoded patterns (useful for identifying a specific object's color), while ColourVest answers "where is this color?" through spatial mapping (useful for searching a scene for a target color). For accessibility practitioners, the work demonstrates how sensory substitution — conveying visual information through touch — can be applied to color perception, not just to spatial or textual information. The wearable form factors (wrist band and vest) enable always-available, hands-free color information, which could benefit not only people with CVD but also situations where color identification is needed in visually demanding or hands-busy contexts.
Tags: colour vision deficiency · haptic feedback · sensory substitution · wearable technology · vibrotactile · color blindness · assistive technology · color identification