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Nicole Tatro, Ian Andrews, Terry Braun, Stephen R Russell; Navigation Assistance From the Low-Vision Enhancement Optoelectronic (LEO) Belt. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4019.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the distance and field detection relationship of a novel prototype device that provides distance amplitude-modulated, single-frequency, cutaneous sensory substitution of visual information obtained by a wide-field distance-measuring camera. This device may signal the presence of peripheral threats and beneficial targets to individuals with retinitis pigmentosa, advanced glaucoma, and other disorders involving compromised peripheral but preserved central vision.
Utilizing an Intel RealSense R200 distance detecting infrared camera (imaging field 40o high by 50o wide), our device inputs object distance information to an Intel Compute Stick running Windows 10 that provides computation, scaling, and WiFi connectivity to each of 8 peripheral actuator boxes containing a Particle Photon WiFi transponder, a linear amplitude to voltage vibration motor, and a battery with self-contained charger. When testing subjects, each actuator box is placed in one of 6 different shirt pocket locations, with 1 worn on each ankle. Each location roughly corresponds to the centroid of the spatial area in front of the patient detected by the infrared camera. We constructed a test device to present objects at known distances within each of the 8 pre-defined peripheral receptive zones of the camera. The testing device (approximately 25 by 14 by 14 feet in size) was built to examine the performance of the detection and the output voltages presented to the actuator boxes for each of the peripheral receptive zones. Output voltages were measured for each actuator at 30.5 cm increments over the distance that the target could be detected.
Using a target size of 0.8 cm diameter, two LEO devices were tested. Targets were repeatedly and reliably detected in each receptive zone at an interval distance of 0.5 meters to 2 meters away from the camera. Across that 1.5-meter range, the voltages (maximal 2.0 V) exhibited a linear relationship (r2 = 0.98) with the distance of the target from the camera.
The results show that the device can accurately detect objects each subfield of the 40 by 50 degree field of view of the camera, and that the vibration actuators receive a voltage that is linearly proportional to the distance of the target from the camera.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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