Resolving subjects and measuring observer/subject distances with a thermal tactile imager

Abstract

Visually-impaired people have difficulty detecting objects beyond the reach of a cane. We functionally coupled a far-infrared camera to a linear array of tactile elements to create a thermal tactile viewer that enhances environmental awareness. Users may scan such a device across a scene to spatially locate people. We observed in a series of acuity-measuring tasks, at twenty feet of observer/subject separation, observers could resolve two people standing four inches apart (a separation angle of 1 degrees ) and locate the angular position of people within a room with 78% accuracy. Additionally, when employing a technique involving two sweeps from two observation points separated by approximately an arm span, subjects correctly reported observer/subject separation distance with 60% accuracy. These observations suggest the technique of information transfer provided by a thermal tactile viewing device provides the fundamental acuity required for an assistive locating device.

A Review on Device-Free Passive Indoor Positioning Methods

“…These devices are relatively expensive. For example, the RAZ-IR Mini, the camera used in [23], costs almost €8000 [24]. Furthermore, quantum detectors, which use a photoelectric effect, are not very suitable for large-scale usage, because they need to cool down to 70 K. Likewise, Golay cell technology is not suitable for large-scale usage, because it is relatively sensitive to vibrations [21].…”

“…Depending on the application and the environment, the thermal imaging system requirements are different. For indoor environment, the technology used in [23] was able to identify the warm targets in the field of view (RAZ-IR mini thermal camera) and produce a tactile feedback. This study used Brailliant 32, a tactile imager, to describe the thermal environment.…”