A Drawing-Aid System using Supervised Learning

Abstract

In an educational front, learning support for handicapped students is important. For these students, several types of support systems and devices have been studied (Fujioka et al., 2006; Uesugi et al., 2005; Ezaki et al., 2005a, 2005b; Kiyota et al., 2005; Burke et al., 2005; Ito, 2004; Nawate et al., 2004, 2005). Among others, for the student suffering from paralysis of a body, drawing on a computer is widely used as occupational therapy. The drawing on a computer usually employs the control devices such as a track ball, a mouse controller, and so on. However, some handicapped students have difficulty in operating these control devices. For this reason, the development of drawing-aid systems has been receiving much attention (Ezaki et al., 2005a, 2005b; Kiyota et al., 2005; Burke et al., 2005; Ito, 2004; Nawate et al., 2004, 2005). In the development of drawing-aid systems, two types of approaches have been studied: a hardware approach and a software approach. In the hardware approach (Ezaki et al., 2005a, 2005b; Kiyota et al., 2005; Burke et al., 2005; Ito, 2004), exclusive control devices must be developed depending on the conditions of handicapped students. Therefore we focused on a software approach (Ito, 2004; Nawate et al., 2004, 2005). In the software approach, the involuntary motion of the hand in device operations is compensated for to draw clear and smooth figures. The influence of the involuntary contraction of muscles caused by the body paralysis can be separated into hand trembling and sudden action. In previous studies of the software approach, several types of compensation methods have been proposed (Ito, 2004; Nawate et al., 2004, 2005; Morimoto & Nawate, 2005; Igarashi et al., 1997; Yu, 2003; Fujioka et al., 2005) to draw clear and smooth figures in real time. Among others, a moving average method (Nawate et al., 2004) is one of the simplest of methods that do not include the difficulty such as figure recognition or realization of natural shapes. The simple algorithm of this method enables drawing-aid in real time. However, this method has difficulty in tracing the tracks of a cursor, because the cursor points in the track are averaged without distinguishing sudden actions from hand trembling. For this reason, a compulsory elimination method (Nawate et al., 2004) is incorporated with the moving average method. In the compulsory elimination method, the points with large differences in angle are eliminated by calculating a movement direction of the track. The judgement of this elimination is determined by a threshold parameter. However, to eliminate the influence of sudden actions, it has difficulty in determining the threshold parameter. Since the degree of sudden action and hand trembling depends on the conditions of handicapped students, the O pe n A cc es s D at ab as e w w w .in te ch w eb .o rg