High Tech Aids Low Vision: A Review of Image Processing for the Visually Impaired.
Recent advances in digital image processing provide promising methods for maximizing the residual vision of the visually impaired. This paper seeks to introduce this field to the readership and describe its current state as found in the literature. A systematic search revealed 37 studies that measure the value of image processing techniques for subjects with low vision. The techniques used are categorized according to their effect and the principal findings are summarized. The majority of participants preferred enhanced images over the original for a wide range of enhancement types. Adapting the contrast and spatial frequency content often improved performance at object recognition and reading speed, as did techniques that attenuate the image background and a technique that induced jitter. A lack of consistency in preference and performance measures was found, as well as a lack of independent studies. Nevertheless, the promising results should encourage further research in order to allow their widespread use in low-vision aids.
EPSRC Centre for Doctoral Training in Applied Photonics, Heriot-Watt University, UK.
Howard
H
Moshtael
Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, UK ; Honorary Professor of Vision Science and Interface Technologies, Heriot-Watt University, UK ; Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
Tariq
T
Aslam
School of Engineering, University of Edinburgh, UK.
Ian
I
Underwood
School of Clinical Sciences, University of Edinburgh, UK.
Baljean
B
Dhillon
image enhancement; image processing; low vision; sensory aid; visually impaired persons