Multiple channel locating

Patent metadata

Field	Value
Publication number	US-10317193-B2
Application number	US-201715607602-A
Country	US
Kind code	B2
Filing date	May 29, 2017
Priority date	Jul 8, 2008
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

Methods, systems, and apparatuses are provided for estimating a location on an object in a three-dimensional scene. Multiple radiation patterns are produced by spatially modulating each of multiple first radiations with a distinct combination of one or more modulating structures, each first radiation having at least one of a distinct radiation path, a distinct source, a distinct source spectrum, or a distinct source polarization with respect to the other first radiations. The location on the object is illuminated with a portion of each of two or more of the radiation patterns, the location producing multiple object radiations, each object radiation produced in response to one of the multiple radiation patterns. Multiple measured values are produced by detecting the object radiations from the location on the object due to each pattern separately using one or more detector elements. The location on the object is estimated based on the multiple measured values.

First claim

What is claimed is:

1. A method for estimating coordinates of a location on an object in a 3D scene, the method comprising:
producing one or more radiation patterns varying along at least two directions, wherein at least a portion of each of the one or more radiations patterns repeats along at least one direction from the at least two directions;
calculating one or more illumination symbols based on the one or more radiation patterns;
illuminating a region of the object with the one or more radiation patterns, wherein the region includes a plurality of locations that includes the location whose coordinates are to be estimated and wherein each illuminated location within the region produces one or more object radiations in response to the one or more radiation patterns;
measuring at least a portion of the one or more object radiations using one or more detector elements to produce a plurality of measured values;
calculating one or more detection symbols from the plurality of measured values;
establishing a correspondence between at least one of the one or more detection symbols and at least one of the one or more illumination symbols, wherein establishing the correspondence between at least one of the one or more detection symbols and at least one of the one or more illumination symbols includes:
calculating a cross-correlation between a single illumination symbol from the one or more illuminations symbols and the one or more detection symbols; and
utilizing the calculated cross-correlation to establish the correspondence; and

estimating the coordinates of the location on the object based on the correspondence between the at least one of the one or more detection symbols and the at least one of the one or more illumination symbols.

2. The method of claim 1 , wherein the portion of each of the one or more radiation patterns that repeats includes two or more maxima.

3. The method of claim 1 , wherein establishing the correspondence between at least one of the one or more detection symbols and at least one of the one or more illumination symbols includes:
calculating a cross-correlation between two or more illumination symbols from the one or more illumination symbols and the one or more detection symbols; and
utilizing the calculated cross-correlation to establish the correspondence.

4. A method for estimating coordinates of a location on an object in a 3D scene, the method comprising:
producing one or more radiation patterns varying along at least two directions, wherein at least a portion of each of the one or more radiations patterns repeats along at least one direction from the at least two directions;
calculating one or more illumination symbols based on the one or more radiation patterns;
illuminating a region of the object with the one or more radiation patterns, wherein the region includes a plurality of locations that includes the location whose coordinates are to be estimated and wherein each illuminated location within the region produces one or more object radiations in response to the one or more radiation patterns;
measuring at least a portion of the one or more object radiations using one or more detector elements to produce a plurality of measured values;
calculating one or more detection symbols from the plurality of measured values;
establishing a correspondence between at least one of the one or more detection symbols and at least one of the one or more illumination symbols; and
estimating the coordinates of the location on the object based on the correspondence between the at least one of the one or more detection symbols and the at least one of the one or more illumination symbols, wherein establishing the correspondence between at least one of the one or more detection symbols and at least one of the one or more illumination symbols includes:
calculating a cross-correlation between two or more illumination symbols from the one or more illumination symbols and the one or more detection symbols; and
utilizing the calculated cross-correlation to establish the correspondence; and
finding a peak cross-correlation among the one or more detection symbols for each illumination symbol from the one or more illumination symbols.

5. A method for estimating coordinates of a location on an object in a 3D scene, the method comprising:
producing one or more radiation patterns varying along at least two directions, wherein at least a portion of each of the one or more radiations patterns repeats along at least one direction from the at least two directions;
calculating one or more illumination symbols based on the one or more radiation patterns;
illuminating a region of the object with the one or more radiation patterns, wherein the region includes a plurality of locations that includes the location whose coordinates are to be estimated and wherein each illuminated location within the region produces one or more object radiations in response to the one or more radiation patterns;
measuring at least a portion of the one or more object radiations using one or more detector elements to produce a plurality of measured values;
calculating one or more detection symbols from the plurality of measured values;
establishing a correspondence between at least one of the one or more detection symbols and at least one of the one or more illumination symbols; and
estimating the coordinates of the location on the object based on the correspondence between the at least one of the one or more detection symbols and the at least one of the one or more illumination symbols, wherein estimating the coordinates of the location on the object includes:
selecting one or more subsets of elements within the one or more detected symbols;
establishing a second correspondence between each subset of elements within the one or more detection symbols and a subset of elements within the one or more illumination symbols; and
estimating the coordinates of the location on the object for each subset based on the second correspondence.

6. The method of claim 1 , wherein at least two radiation patterns from the one or more radiation patterns are projected sequentially.

7. The method of claim 1 , wherein at least calculating the one or more detection symbols or calculating the one of more illumination symbols comprises at least removing a common offset, removing a common scale factor, or applying a remapping function.

8. The method of claim 1 , further comprising estimating a three-dimensional surface of the object from a plurality of location coordinate estimations.

9. A system for estimating coordinates of a location on an object in a 3D scene, the system comprising:
a pattern projector configured to produce one or more radiation patterns varying along at least two directions and repeating at least a portion of each of the one or more radiation patterns along at least one direction and configured to be oriented such that a region on the object encompassing the location whose coordinates are to be estimated is illuminated;
a detector array configured to measure at least a portion of the object radiations produced by each illuminated location within the region in response to the one or more radiation patterns to produce a plurality of measured values; and
one or more processors configured to:
calculate a detection symbol from the plurality of measured values;
estimate a correspondence between the detection symbol and an illumination symbol from one or more illumination symbols, wherein estimating the correspondence between the detection symbol and the illumination symbol includes:
calculating a cross-correlation between the illumination symbol and the detection symbol; and
utilizing the calculated cross-correlation to estimate the co

Assignees

• Cognex Corp

Inventors

• Braker Benjamin
• Moore Eric
• Feldkhun Daniel

Classifications

• G01S7/486

  Receivers · CPC title

• G01S7/499

  using polarisation effects · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01B11/2527

  with phase change by in-plane movement of the patern · CPC title

• G01B11/2536

  using several gratings with variable grating pitch, projected on the object with the same angle of incidence · CPC title