Patent applications are being filed round the world by Transducer Valley of Finland (WO 91/15781) for a helmet which divers and firemen can wear on rescue operations in muddy water or thick smoke.
The helmet has a convex array of ultrasound transducers on the front generating a focused beam which scans the area ahead. In between pulses, the transducers function as receivers, picking up reflections from any object hidden in the smoke or mud ahead.
These reflected pulses control a small panel of light-emitting diodes, in front of the wearer's eyes. The panel displays an image, like a coarse television picture, of what lies ahead.
The strength of the returning echoes controls the brightness of the LEDs to help the wearer distinguish between solid objects, such as a human body, and undergrowth or water weeds. With a pair of LED panels, the wearer sees a three-dimensional image and so can ...
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