Surveying Instrument Camera Eccentricity Compensation

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Solution Overview

Problem

In surveying instruments with eccentric camera and instrument centers, the camera image center does not align with the measurement point, requiring manual compensation for target distance, which is inconvenient and prone to error.

Innovation Solution

A computer-implemented method that automatically compensates for the offset between the tracking camera and the distance measuring device by using angle encoders and a drive system to rotate the surveying instrument components, ensuring accurate alignment without user interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual compensation for camera eccentricity is implemented, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvealignment accuracyVSAvoiduser convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system automatically performs the eccentricity compensation calculation and adjustment without requiring user intervention. The computer system computes the offset between camera center and instrument center, then automatically adjusts the virtual indicator position based on target distance, eliminating the need for manual compensation while maintaining measurement precision.

Inventive Principle:
Principle #25Self-service

2Productivity

If automatic tracking is implemented, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvetracking efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system continuously captures images of the target, computes the offset between the virtual indicator and target center, and automatically adjusts the measuring head orientation based on this feedback. This closed-loop control enables automatic tracking that improves productivity while managing complexity through algorithmic rather than mechanical solutions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical tracking mechanisms with computational methods. The computer system calculates the required orientation adjustments based on image analysis and communicates these to the drive system, substituting mechanical complexity with software-based control that achieves the same tracking function more efficiently.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If virtual indicator alignment is adjusted for target distance, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvecrosshair alignmentVSAvoidalignment convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system pre-computes the offset between camera center and instrument center during setup. This preliminary calibration allows the system to automatically apply the correct virtual indicator position for any target distance without requiring the user to perform manual alignment adjustments, thereby maintaining precision while improving operational convenience.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4556848A1Method for operating a surveying instrument to track a target
Publication Date: 2025.05.21 HILTI AG
  • EP4556848A1 patent drawingFigure 1
  • EP4556848A1 patent drawingFigure 2A
  • EP4556848A1 patent drawingFigure 2B

AI summary

Computer-implemented method for operating a surveying instrument to track a target in a worksite, in which the surveying instrument and the target are deployed, comprising the steps: Instructing the tracking light source to emit tracking light, instructing the tracking camera to capture a first image, which shows the target to be tracked, instructing the drive system to rotate the measuring head to an orientation, in which, in the first image, a virtual indicator is aligned to the target, in that orientation, instructing the first angle encoder to measure first angle data in the first plane and/or the second angle encoder to measure second angle data in the second plane, computing a first angle gap in the first plane and/or a second angle gap in the second plane based on a distance value of the surveying instrument to the target and on the first offset, and instructing the drive system to rotate the support about the first angle gap and/or the measuring head about the second angle gap.