Materialbestämning och Komplettering av Time-of-Flight-kamera med Hjälp av Ultraljud

Sammanfattning: For people with blindness or visual impairment, everyday life risks being characterized by mental problems, loneliness and low mobility. At the same time, research shows that social interaction and movement in particular contribute to a higher quality of life. That is why the aid Audomni is currently being developed at the Faculty of Engineering at Lund University. Audomni uses a Time-of-Flight camera to convert the visual impressions of the surroundings into sound. Camera technology encounters challenges when it comes to reading reflective and transparent materials, which results in incorrect depth measurements. It is therefore of interest to explore possible solutions to this. Ultrasound is here presented as a possible technology to supplement the reading of the environment. Ultrasound can be used both to record distances where the Time-of-Flight camera is unable to, and to determine what material is being read, especially where the camera fails to adequately measure the environment. In addition, the technology can be applied in the test stages of Audomni, when collecting data for a test environment in virtual reality, where the user of Audomni learns to use the aid in a safe environment. Material information is obtained by studying the amplitude of the echo signal. Examination of the test materials cardboard, arm with jacket, arm without jacket, wall, sheet metal, glass, plexiglass and mirror was done at distances of 0.25, 0.5, 0.75 and 1 meter. The tests show that ultrasound measures distances with lower measurement deviations compared to the camera, especially for the materials sheet metal, glass, plexiglass and mirror. Ultrasound is thus a promising technology both for supplementing the Time-of-Flight camera and for material recognition.