Method for optically scanning and measuring an object

• US 8,625,106 B2
• Filed: 07/20/2010
• Issued: 01/07/2014
• Est. Priority Date: 07/22/2009
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Ossig, Martin, Schumann, Philipp
• Primary Examiner(s): NGUYEN, TU T
• Application Number:
  US13/384,795
• Publication Number:
  US 20120133953A1
• Time in Patent Office: 1,267 Days
• Field of Search: 356/601
• US Class Current: 356/601
• CPC Class Codes: G01S 17/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

In a method for optically scanning and measuring an object by a laser scanner by a procedure in which a emission light beam modulated with a target frequency is emitted by means of a light emitter, a reception light beam reflected or otherwise scattered in some way from an object in the surroundings of the laser scanner is received, with a measuring clock, as a multiplicity of samples by means of a light receiver and in each case at least the distance from the object is determined from the phase angles of the multiplicity of samples for a plurality of measuring points by means of a control and evaluation device, for determining the distances, a phase shift caused by a distance difference of temporal adjacent samples is corrected in order to correct the distances.

Claims

1. A method for optically scanning and measuring an object by a laser scanner, comprising the steps of:

modulating an emission light beam with a target frequency;

emitting the emission light beam;

receiving a reception light beam reflected or otherwise scattered from the object in surroundings of the laser scanner, with a measuring clock, as a multiplicity of samples by a light receiver;

determining in each case at least a distance from the laser scanner to the object from phase angles of the multiplicity of samples for a plurality of measuring points by a control and evaluation device; and

correcting a phase shift caused by a distance difference of temporal adjacent samples to correct the determined distances.

2. The method of claim 1, the step of correcting a phase shift further comprising determining a virtual speed of the object for correcting the phase shift.

3. The method of claim 2, wherein the speed is determined from the distance difference existing between the distances of two temporally adjacent samples and the measuring clock.

4. The method of claim 2, wherein an approximated phase shift is determined from the virtual speed.

5. The method of claim 4, wherein corrected distances of the samples are determined from the approximated phase shift.

6. The method of claim 1, wherein the correction of the phase shift is effected iteratively.

7. The method of claim 1, wherein the multiplicity of samples with corrected distances are combined with data reduction to form the plurality of measuring points.