Web Navigation Tool for Visually Impaired People

Introduction

The internet has become a mass communication media that links the whole world together; it does provide knowledge, experience, news, social networks, E-commerce and jobs offers. Blind and visually impaired people need internet access means in their daily life in order to enroll into jobs and extend their knowledge sources. Most of the access means available to visually impaired people are expensive and not dedicated to the internet navigation (e.g., Sriskanthan et al., 1990). The major issue among these tools is their high cost (Freedom Scientific, 2012a, 2012b; King et al., 2004). These means vary greatly in the level of user convenience they provide. They include screen readers (Freedom Scientific, 201b2), screen magnifiers (for those who are not totally blind) (Pearson, 2002), Braille printers and Braille tactile displays. Each method has its advantages and limitations as will be illustrated. Screen magnifiers are not suitable for totally blind individuals. Blind people who are using hardcopy Braille printout or synthesized voice (Josifovski, 1997) output from the computer face limitations of interaction speed and accuracy. They do not have the flexibility of ‘reading’ the screen and making the necessary changes interactively or instantaneously. To receive and process the voice output, the person using the computer must be quite alert in listening. Also, the vocabulary of the synthesized voice is limited. Words with slightly different spelling but having similar phonetics may be pronounced in the same manner, leading to incorrect interpretation. Character by character sound output is very slow for interactive use of computers. A soft Braille display device, on the other hand, allows the users to ‘read’ the characters at their own pace and make on-line changes instantaneously (Sriskanthan et al., 1990).

Braille Display Terminal (BDT) that recognizes the text on the screen and displays it in the Braille display has been reported in (Sriskanthan, 1990). This is a cell-based unit which displays 40 characters at a time. This BDT is implemented as an expansion card that fits into the PC expansion slot. Braille dots were implemented using thermo-plastic pins that expand on heating and contract on cooling. Another display device that reads data from a file has been reported (Huang et al., 2010). This e-reader converts both the Chinese and English characters into the corresponding Braille code and allows data entry from the keyboard. A similar prototype, termed the Tactobook (Velazquez, 2008) consists of a computer-based system that translates fast and automatically any eBook into Braille. Devices converting images into a tactile display have been investigated and used. Bliss et al. (1970) used a 24×6 array of pins driven by piezoelectric bimorphs to produce a tactile representation of an optical image. Another device used an 8×8 arrangement of tactile pins actuated by shape memory alloys (Velazquez, 2006). Another 3D prototype was reported by Shinohara et al. (1998). This consisted of a 64×64 array of pins aligned in a hexagonal structure. Each pin can be raised in discrete steps giving the overall 3D tactile sense.