Laser range finding apparatus
First Claim
1. Laser range finding apparatus comprising a pulsed laser (11), a light deflecting device (15), a photodetector arrangement (22) having an opto-electronic photodetector (23) and an electronic control and evaluation system (10), wherein the pulsed laser (11) is controlled to transmit light pulses (12) and the sequential light pulses (12) that are transmitted are deflected via the light deflecting device (15) at changing angles into a measurement region (13), wherein the light pulses (12'"'"') reflected back from an object (14) located in the measurement region (13) are received by the photodetector arrangement (22), wherein a sensing signal representative for the range of the object (14) from the light deflecting device (15) is found in the electronic control and evaluation system (10) in accordance with the pulse transit time method from the time between the transmission and the reception of a light pulse (12, 12'"'"') on taking account of the speed of light, and wherein a compensation is also effected for transit time measurement errors arising as a result of signal dynamics, characterized in thatthe electronic control and evaluation system (10) includes means (C, 36, 37;
- 34,
38) for measuring the total electrical charge which has flowed via the photodetector (23) during the reception of a light pulse (12'"'"') and/or for measuring the pulse width of the received light pulse (12'"'"'); and
in that the compensation of the transit time error which occurs as a result of the signal dynamics, takes place in dependence on the measured electrical charge and/or the pulse width on the basis of respective correction values which are determined by the electronic control and evaluation system (10) as a result of charges and/or pulse widths and pulse transit times which were measured with respect to at least one reference object (86) arranged at a defined distance from the light deflecting device (15) and having different reflectivities.
1 Assignment
0 Petitions
Accused Products
Abstract
A laser range finding apparatus comprises a pulse laser (11), a light deflecting device, a photodetector arrangement (22) having an opto-electronic photodetector (23) and also an electronic control and evaluation system (10) in which a sensing signal representative for the range of an object is determined in accordance with the pulse transit time method from the time between the transmission and reception of a light pulse taking account of the speed of light. The electronic control and evaluation system (10) includes means for measuring the total electrical charge which has flowed via the photodetector (23) during the reception of a light pulse and/or for the measurement of the pulse width of the received light pulse. The compensation takes place as a result of the transit time measurement errors which arise as a result of the signal dynamics in dependence on the measured electrical charge or pulse width on the basis of respective correction values which were determined by the electronic control and evaluation system with respect to charges or pulse widths and pulse transit times, which were measured with respect to at least one reference object (86) having different reflectivities and arranged at a defined range from the light deflecting device (15).
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Citations
21 Claims
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1. Laser range finding apparatus comprising a pulsed laser (11), a light deflecting device (15), a photodetector arrangement (22) having an opto-electronic photodetector (23) and an electronic control and evaluation system (10), wherein the pulsed laser (11) is controlled to transmit light pulses (12) and the sequential light pulses (12) that are transmitted are deflected via the light deflecting device (15) at changing angles into a measurement region (13), wherein the light pulses (12'"'"') reflected back from an object (14) located in the measurement region (13) are received by the photodetector arrangement (22), wherein a sensing signal representative for the range of the object (14) from the light deflecting device (15) is found in the electronic control and evaluation system (10) in accordance with the pulse transit time method from the time between the transmission and the reception of a light pulse (12, 12'"'"') on taking account of the speed of light, and wherein a compensation is also effected for transit time measurement errors arising as a result of signal dynamics, characterized in that
the electronic control and evaluation system (10) includes means (C, 36, 37; - 34,
38) for measuring the total electrical charge which has flowed via the photodetector (23) during the reception of a light pulse (12'"'"') and/or for measuring the pulse width of the received light pulse (12'"'"'); and
in that the compensation of the transit time error which occurs as a result of the signal dynamics, takes place in dependence on the measured electrical charge and/or the pulse width on the basis of respective correction values which are determined by the electronic control and evaluation system (10) as a result of charges and/or pulse widths and pulse transit times which were measured with respect to at least one reference object (86) arranged at a defined distance from the light deflecting device (15) and having different reflectivities. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A laser range finding apparatus comprising a pulsed laser directing light pulses towards an object that is spaced from the apparatus;
- a photodetector receiving light pulses reflected by the object;
an evaluation circuit generating distance signals reflecting a distance between the object and the apparatus from a pulse transit time between a transmission and reception of light pulses by the apparatus using the speed of light;
a deflector arranged between the laser and the object for angularly deflecting sequential light pulses to change their angular positions relative to the object;
a transmitter sending to the evaluation circuit angular position signals representative of the angular positions of the sequential light pulses;
the evaluation circuit being adapted to determine the distance between the object and the apparatus from the distance signal and the angular position signal;
a control circuit operatively connected with the evaluation circuit for measuring at least one of an electrical charge which has flowed through the photodetector during the reception of a light pulse and a pulse width of a received light pulse; and
a reference object located at a defined distance from the apparatus;
the evaluation circuit further generating needed correction values for correcting errors in the distance signals caused by signal dynamics by comparing the at least one of the electrical charge which has flowed through the photodetector and the pulse width with at least one of a corresponding electrical charge which has flowed through the photodetector and a pulse width resulting from a reference laser light pulse reflected by the object. - View Dependent Claims (20, 21)
- a photodetector receiving light pulses reflected by the object;
Specification