Conveying visual information with spatial auditory patterns

Humans can perceive their spatial surroundings both by the visual and the auditory senses. Even though the auditory system has much lower spatial resolution, it can still serve as an alternative or supplementary information channel for the visual modality. We investigate the feasibility of conveying elaborate visual information by auditory patterns. A system is developed that transforms 2-D binary images into "auditory images." Such images are based on slow raster scanning of a perceptual auditory surface around the subject while emitting sounds that correspond to the brightness level of the images at each location. The parameters involved in such a system are quantitatively investigated with respect to their effect on performance. These parameters include resolution, level difference, sound color contrast, speed, surface curvature, etc. The graphic percepts of synthetic auditory images that correspond to simple shapes are also analyzed. The experimental results show that sound localization can be used to convey visual information quite successfully for simple shapes and low-resolution patterns.