Range measurement for active optical recognition devices
First Claim
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1. A laser range echo device for measuring distances in the decimeter range, comprising:
- (a) laser beam transmitting means for transmitting a pulse of laser light toward a target;
(b) start pulse generating means for generating a start pulse upon transmission of said laser pulse;
(c) laser receiver means for generating a stop pulse in response to the receipt of the reflection of said laser light pulse from said target;
(d) a high-speed switch arranged to be actuated for a predetermined time following the onset of said start pulse;
(e) capacitive means for producing a ramp voltage in response to the actuation of said switch, said ramped voltage changing substantially linearly from a starting value to an ending value in a matter of nanoseconds; and
(f) a flash A/D converter arranged to sample the instantaneous value of said ramped voltage in response to said stop pulse;
(g) whereby said flash A/D converter provides a digital representation of said instantaneous value with an accuracy sufficient to digitally represent the travel distance of said laser light pulse in increments in the decimeter range.
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Abstract
An inexpensive, reliable analog ramped-voltage timing device (34, 36, 38, 40, 44) can be used in a laser echo ranging device capable of resolution in the decimeter range by using a very steep ramp (42), and a flash A/D converter (50) to instantaneouly sample the ramped voltage upon receipt of the laser echo.
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Citations
8 Claims
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1. A laser range echo device for measuring distances in the decimeter range, comprising:
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(a) laser beam transmitting means for transmitting a pulse of laser light toward a target; (b) start pulse generating means for generating a start pulse upon transmission of said laser pulse; (c) laser receiver means for generating a stop pulse in response to the receipt of the reflection of said laser light pulse from said target; (d) a high-speed switch arranged to be actuated for a predetermined time following the onset of said start pulse; (e) capacitive means for producing a ramp voltage in response to the actuation of said switch, said ramped voltage changing substantially linearly from a starting value to an ending value in a matter of nanoseconds; and (f) a flash A/D converter arranged to sample the instantaneous value of said ramped voltage in response to said stop pulse; (g) whereby said flash A/D converter provides a digital representation of said instantaneous value with an accuracy sufficient to digitally represent the travel distance of said laser light pulse in increments in the decimeter range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification