Signing on the tactile line
ACM Transactions on Computer-Human Interaction
We present McSig, a multimodal system for teaching blind children cursive handwriting so that they can create a personal signature. For blind people handwriting is very difficult to learn as it is a near-zero feedback activity that is needed only occasionally, yet in important situations; for example, to make an attractive and repeatable signature for legal contracts. McSig aids the teaching of signatures by translating digital ink from the teacher's stylus gestures into three non-visual forms:
... (1) audio pan and pitch represents the x and y movement of the stylus; (2) kinaesthetic information is provided to the student through a force-feedback haptic pen that mimics the teacher's stylus movement; and (3) a physical tactile line on the writing sheet is created by the haptic pen. McSig has been developed over two major iterations of design, usability testing and evaluation. The final step of the first iteration was a short evaluation with eight visually impaired children. The results suggested that McSig had the highest potential benefit for congenitally and totally blind children and also indicated some areas where McSig could be enhanced. The second prototype incorporated significant modifications to the system, improving the audio, tactile and force-feedback. We then ran a detailed, longitudinal evaluation over 14 weeks with three of the congenitally blind children to assess McSig's effectiveness in teaching the creation of signatures. Results demonstrated the effectiveness of McSig-they all made considerable progress in learning to create a recognizable signature. By the end of ten lessons, two of the children could form a complete, repeatable signature unaided, the third could do so with a little verbal prompting. Furthermore, during this project, we have learnt valuable lessons about providing consistent feedback between different communications channels (by manual interactions, haptic device, pen correction) that will be of interest to others developing multimodal systems.