Multi-Sensor Extrinsic Drift Detection from Pose Change Inconsistency

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Solution Overview

Problem

The accuracy of detection systems is compromised due to changes in the relative pose relationship between sensors caused by factors like vibration and mechanical wear, leading to inconsistent extrinsic parameters.

Innovation Solution

A method and apparatus for detecting changes in extrinsic parameters by acquiring pose data from multiple sensors, determining differences in pose changes, and identifying parameter changes when the difference exceeds a preset level, allowing for recalibration to maintain accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple sensors are used to enhance detection functions, then detection capability is improved, but extrinsic parameter calibration accuracy deteriorates due to pose changes from vibration and mechanical wear

Engineering Contradiction:
Improvedetection capabilityVSAvoidextrinsic parameter calibration accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism by continuously monitoring pose data from sensors and comparing actual pose changes against expected changes based on calibrated extrinsic parameters. When deviations exceed a threshold, the system triggers recalibration, creating a closed-loop system that maintains accuracy despite environmental disturbances like vibration and mechanical wear

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary extrinsic parameter calibration before deployment and uses this pre-calibrated data as a reference baseline. By having the calibrated parameters available in advance, the system can quickly detect anomalies by comparing real-time sensor data against this predetermined reference, enabling rapid response to drift without requiring continuous complex recalibration

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If extrinsic parameters are recalibrated frequently to maintain accuracy, then detection accuracy is improved, but system complexity and calibration time increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidcalibration process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of performing full recalibration routines continuously, the system applies partial action by only triggering recalibration when necessary - specifically when pose change deviations exceed a predefined threshold. This selective approach performs calibration only partially (when needed) rather than excessively (continuously), reducing overall system complexity while maintaining detection accuracy

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system monitors changes in extrinsic parameters over time and triggers recalibration only when parameter drift exceeds acceptable thresholds. By changing the calibration state selectively based on parameter degradation rather than on a fixed schedule, the system optimizes the balance between maintaining accuracy and reducing calibration overhead

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If real-time pose data monitoring is implemented to detect extrinsic parameter changes, then calibration accuracy is maintained, but computational load and processing time increase

Engineering Contradiction:
Improvecalibration accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts and monitors only the critical elements needed for detecting extrinsic parameter changes - specifically pose data from sensors and derived pose changes - rather than processing all sensor data. By taking out only the essential information related to relative sensor positioning, the system maintains calibration accuracy while significantly reducing computational load and processing time

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4155673B1Extrinsic parameter change detection method and apparatus, electronic device, and detection system
Publication Date: 2026.04.08 HANGZHOU HIKVISION DIGITAL TECHNOLOGY CO LTD
  • EP4155673B1 patent drawingFigure 1~2
  • EP4155673B1 patent drawingFigure 3~4
  • EP4155673B1 patent drawingFigure 5~6

AI summary

The present application discloses a method and an apparatus for detecting changes of extrinsic parameters, an electronic device and a detection system. Constrained by extrinsic parameters, if the pose of one of the two sensors with calibrated extrinsic parameters changes at different moments, the pose of the other sensor should also change synchronously, and the pose changes of the two sensors should be consistent. This consistency is reflected in that coordinate transformation is performed through the calibrated extrinsic parameters to convert the pose of the two sensors to a same coordinate system, in which there is no difference in the pose changes of the two sensors. However, if it is determined, according to respective pieces of pose data of any two sensors in a plurality of sensors at different moments, that there is a difference in the pose change between the two sensors, and the difference in the pose change reaches a preset difference level, it means that the pose changes of the two sensors are inconsistent, so that it can be determined that the extrinsic parameters of the two sensors have changed, and the detection of the changes of the extrinsic parameters of the sensors is realized.