Structured Light Measurement Without Triangulation Calibration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional imaging systems for determining object characteristics require complex computations and calibration procedures, necessitating precise knowledge of spatial 3D relationships between camera, laser emitting device, and ground surface, which is time-consuming and often requires dedicated equipment, and recalibration if positional relationships change.

Innovation Solution

The method involves interpolating object characteristics using stored associations between known values and representations of laser line projections, eliminating the need for complex computations and calibration procedures by determining object characteristics based on relative 3D positions and orientations of the camera and laser device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If triangulation computations are used to determine object characteristics, then measurement precision is improved, but device complexity and calibration requirements increase

Engineering Contradiction:
Improveobject characteristic measurementVSAvoidcalibration procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary calibration by capturing images of training objects with known characteristics and storing the associations between laser line representations and characteristic values in a lookup table. This preliminary action eliminates the need for complex triangulation computations during actual measurement, as the system directly queries the pre-computed associations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates a computational model by capturing and storing representations of laser lines on training objects with known characteristics. These stored representations serve as reference copies that enable direct comparison and measurement without requiring repeated complex geometric computations.

Inventive Principle:
Principle #26Copying

2Reliability

If precise 3D relationships are established during manufacturing, then measurement reliability is improved, but manufacturing complexity and time increase

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs self-calibration by automatically capturing images of training objects, computing the associations between laser line representations and known characteristics, and populating the lookup table without requiring external calibration equipment or manual intervention. This self-service approach reduces both calibration time and manufacturing complexity.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If dedicated calibration equipment is used, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecharacteristic measurement precisionVSAvoidcalibration equipment requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses simple training objects with known characteristics as calibration references instead of expensive dedicated calibration equipment like checkerboard plates. These training objects serve as disposable or reusable references that enable accurate measurement without requiring sophisticated calibration tools.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Ease of operation

If simple relative geometry is enforced between camera and laser emitter, then ease of operation is improved, but adaptability decreases

Engineering Contradiction:
Improvesystem configuration simplicityVSAvoidsystem configuration flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system performs preliminary calibration for each specific configuration by capturing images of training objects and storing configuration-specific associations in the lookup table. This preliminary action enables the system to adapt to different camera-laser geometries without requiring simple fixed relationships, as each configuration is pre-characterized and stored.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12493987B2Calibration-less structured light measurement
Publication Date: 2025.12.09 COGNEX CORP
  • US12493987B2 patent drawing
  • US12493987B2 patent drawing
  • US12493987B2 patent drawing

AI summary

The techniques described herein relate to methods, apparatus, and computer readable media for measuring object characteristics by interpolating the object characteristics using stored associations. A first image of at least part of a ground surface with a first representation of a laser line projected onto the ground surface from a first pose is received. A first association between a known value of the characteristic of the ground surface of the first image with the first representation is determined. A second image of at least part of a first training object on the ground surface with a second representation of the laser line projected onto the first training object from the first pose is received. A second association between a known value of the characteristic of the first training object with the second representation is determined. The first and second association for measuring the characteristic of a new object are stored.