Method for eliminating internal reflection of range finding system and range finding system applying the same
AssigneeAsia Optical Co., Inc.
InventorChih-wei Hung
Life of this patent
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Abstract
A method for eliminating internal reflection signal in a range finding system is disclosed, including the steps of receiving a range-finding signal reflected by an object and an internal reflection signal caused by internal reflection of the range finding system, converting the range finding signal and internal reflection signal, as a combination, into an electrical current signal, cropping the electrical current signal in a time interval for the electrical current signal to pass so as to generate a first electrical signal indicating the internal reflection signal, and subtracting the first electrical signal from the current signal to provide a second electrical signal representing the range-finding signal reflected by the object.
Claims16
A method for eliminating internal reflection in a range finding system that transmits a first light beam along a first optic path to an object and receives a second light beam reflected by the object, internal reflection inducing by the first light beam in the range finding system being received by the range finding system as an internal reflection signal, the method comprising:
- (1) detecting an optical signal in the operation of the range finding system as a combination of the internal reflection signal and the second light beam;
- (2) converting the optical signal into an electrical current;
- (3) cropping the electrical current in a time interval for the electrical current to pass so as to generate a first electrical output corresponding to the internal reflection signal;
- and
- (4) subtracting the first electrical output from the electrical current to obtain a second electrical output representing the second light beam.
A range finding system comprising:
- a laser transmitter that emits a first laser beam toward an object, which reflects the first laser beam as a second laser beam;
- and
- a receiver that receives an optical signal as a combination of the second light beam from the object and an optical noise induced as an internal reflection of the range finding system, the receiver comprising a circuit comprising:
- an optical detector that detects the optical signal and, in response thereto, generates an electrical current,
- a time-depended switch that crops the electrical current in a time interval for the electrical current to pass so as to generate a first electrical signal corresponding to the optical noise, and
- a subtracter that receives both the electrical current and the first electrical signal and subtracts the first electrical signal from the electrical current to provide a second electrical signal representing the second light beam.
A signal processing method for a range finding system of a laser sight, comprising the following steps:
- (a) emitting a range-finding beam to an object, which in turn provides a reflected beam as a reflection of the range-finding beam;
- (b) receiving an optical signal as a combination of the reflected beam and an internal reflection signal;
- (c) converting the optical signal into an electrical signal;
- (d) cropping the electrical signal in a time interval for the electrical signal to pass so as to generate a first output signal corresponding to the internal reflection signal;
- and
- (e) subtracting the first output signal from the electrical signal to generate a second output signal representing the reflected beam.
Dependencies are inferred from the claim text.