”I can’t name it, but I can perceive it” Conceptual and Operational Design of ”Tactile Accuracy” Assisting Tactile Image Cognition

Abstract

Designing a tactile image for blind people is a significant challenge due to the difficulty of recognizing objects on a 2D line drawing image by touch compared to vision. In this paper, we proposed ”tactile accuracy”, a new criterion to evaluate the performance of recognizing 242 raised line images of common objects for 30 subjects (10 blindfolded sighted subjects, 10 congenitally blind subjects, and 10 late blind subjects), instead of the conventional ”naming accuracy” used in the visual image recognition tasks. We used multi-level evaluation criteria including ”tactile accuracy” to systematically analyze the design factors in tactile images. The results showed that using multi-level evaluate criteria could help unveil the tactile cognitive preferences of different types of subjects for personalized learning. Moreover, we reported important design factors that affect tactile image recognition, thus providing guidelines on the design of tactile images.