2.3.1. Haptics

The haptic methods for the visually impaired person can offer more methods for interaction with the other human senses, such as hearing, and do not interfere with them. It has been noted in studies that the visually impaired have higher memorization abilities and recognition of haptic tasks [83]. The advantages of haptic feedback are high privacy, because only the person can observe the stimuli, as well as usefulness in high-noise environments and the fact that they can expand the person's experience as an additional communicational channel [84]. Buimer et al. [62] presented an experiment of a technique used to recognize facial emotion and send feedback through a vibration belt to the user. The authors conveyed information regarding six emotions by installing six vibration units in a belt. Even though the technique has accuracy problems, the satisfactory results of this method are based on a study of eight visually impaired people. Five of them found that the belt was easy to use and could interpret the feedback while conversing with another person. Meanwhile, the other three found its use difficult. Gonzalez-Canete et al. have proposed Tactons, whereby they identified sixteen applications with different vibration signals so that they could be distinguished from one another. The authors found that musical techniques for haptic icons are more recognizable and can be further distinguished. In addition, adding complicated vibrotactile sensations to smartphones is a significant benefit for users with any kind of sensory disability. The authors measured the recognition rate of the VI users and non-VI users. They found that non-VI users scored higher rates, especially with identification applications that they were familiar with, but when they used the reinforcement learning stage, in which some feedback is provided to the users, the recognition rate of the VI users increased [84].
