Light-integrating rangefinding device and method
First Claim
1. A method for optically measuring a range R of an object from a rangefinding device, comprising the steps of:
- a) emitting a train of light pulses from said rangefinding device toward said object for reflection thereby, each of said light pulses having an emission time and having a pulse duration corresponding to a round-trip time to a maximum range;
b) detecting light received by said rangefinding device during three time intervals of a same gate duration, said gate duration corresponding to twice the pulse duration, said time intervals being determined by;
a background gate closing at the emission time of one of said light pulses;
a ranging gate centered on the emission time of another one of said light pulses; and
a pulse energy gate opening at the emission time of yet another one of said light pulses;
c) integrating light detected during each of said time intervals, thereby obtaining an integrated light value for each of said gates;
d) normalizing the integrated light value for said ranging gate using the integrated light values for the background and pulse energy gates, thereby obtaining a normalized ranging measurement; and
e) determining said range R of the object from said normalized ranging measurement and calibration data.
9 Assignments
0 Petitions
Accused Products
Abstract
A rangefinding device and a method for determining the range of an object from a rangefinding device are provided. A train of light pulses each having an emission time and a pulse duration is generated. The pulse duration is set to twice the round-trip time to a maximum range of the device. The light pulses are reflected back toward the device by the object and detected according to three time intervals, respectively determined by a background gate, a ranging gate and a pulse energy gate. The light energy received during each interval is integrated and the integrated light value corresponding to the ranging gate is normalized using the values from the other two intervals. The range of the object is determined from the normalized ranging measurement and calibration data.
-
Citations
19 Claims
-
1. A method for optically measuring a range R of an object from a rangefinding device, comprising the steps of:
-
a) emitting a train of light pulses from said rangefinding device toward said object for reflection thereby, each of said light pulses having an emission time and having a pulse duration corresponding to a round-trip time to a maximum range; b) detecting light received by said rangefinding device during three time intervals of a same gate duration, said gate duration corresponding to twice the pulse duration, said time intervals being determined by; a background gate closing at the emission time of one of said light pulses; a ranging gate centered on the emission time of another one of said light pulses; and a pulse energy gate opening at the emission time of yet another one of said light pulses; c) integrating light detected during each of said time intervals, thereby obtaining an integrated light value for each of said gates; d) normalizing the integrated light value for said ranging gate using the integrated light values for the background and pulse energy gates, thereby obtaining a normalized ranging measurement; and e) determining said range R of the object from said normalized ranging measurement and calibration data. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A rangefinding device for optically measuring a range R of an object therefrom, comprising:
-
an emitter module for emitting a train of light pulses toward said object for reflection thereby, each of said light pulses having an emission time and having a pulse duration corresponding to a round-trip time to a maximum range; a receiver module for detecting light received thereby during three time intervals of a same gate duration, said gate duration corresponding to twice the pulse duration, said time intervals being determined by a background gate closing at the emission time of one of said light pulses, a ranging gate centered on the emission time of another one of said light pulses, and a pulse energy gate opening at the emission time of yet another one of said light pulses; integrating means for integrating light detected during each of said time intervals, thereby obtaining an integrated light value for each of said gates; normalizing means for normalizing the integrated light value for said ranging gate using the integrated light values for the background and pulse energy gates, thereby obtaining a normalized ranging measurement; and determining means for determining said range R of the object from said normalized ranging measurement and calibration data. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
Specification