Camera Homography Recalibration for Accurate Item Tracking

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Solution Overview

Problem

Existing systems face challenges in efficiently identifying and tracking multiple items in real-time due to computational intensity and inaccuracy caused by shifts in camera, 3D sensor, and platform positions, which are difficult to detect and maintain without labor-intensive routine maintenance.

Innovation Solution

A system using cameras and 3D sensors to identify and track items, with continuous monitoring and recalibration of homography to maintain accurate pixel-to-physical location mapping, even in dynamic environments, and techniques for intelligent detection of triggering events and item placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If initial homography is used for pixel-to-physical location mapping, then the system can operate without continuous recalibration, but accuracy deteriorates when camera, 3D sensor, or platform positions shift

Engineering Contradiction:
Improvemapping accuracyVSAvoidrecalibration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system continuously monitors the accuracy of pixel-to-physical location mapping by comparing detected item positions with expected positions. When deviations exceed a threshold, the system triggers automatic recalibration of the homography parameters, creating a closed-loop feedback mechanism that maintains accuracy without requiring manual intervention

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-calibration by automatically detecting position shifts of cameras, 3D sensors, or platform using reference markers or known geometric features in the scene. The homography parameters are updated autonomously based on detected deviations, eliminating the need for labor-intensive manual recalibration while maintaining mapping accuracy

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If comprehensive item identification and tracking is performed, then system functionality is improved, but computational load increases

Engineering Contradiction:
Improveitem identification capabilityVSAvoidcomputational load
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The system divides the computational task into multiple stages: first detecting triggering events and item placement using simplified criteria, then performing detailed identification and tracking only on detected items. This segmented approach processes only relevant data rather than analyzing all sensor data comprehensively, reducing overall computational load while maintaining identification capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs partial identification by detecting key features and characteristics sufficient for item recognition without processing all possible item attributes. Tracking is performed at reduced fidelity using approximate positions and simplified motion models, providing adequate functionality with lower computational requirements than full comprehensive processing

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS12586220B2System and method for camera re-calibration based on an updated homography
Publication Date: 2026.03.24 7-ELEVEN INC
  • US12586220B2 patent drawing
  • US12586220B2 patent drawing
  • US12586220B2 patent drawing

AI summary

A device for object tracking receives an image from a camera, where the image shows a set of points on a calibration board placed on a platform. The device determines a pixel location array that comprises pixel locations associated with the points in the image. The device determines, by applying a first homography to the pixel location array, a calculated location array identifying calculated physical location coordinates of the set of points in the global plane. The device determines that the difference between a reference location array and the calculated location array is more than a threshold value. In response, the device determines that the camera and/or the platform has moved from a respective initial location when the first homography was determined. The device determines a second homography by multiplying an inverse of the pixel location array by the reference location array and calibrates the camera using the second homography.