Image-Frame Reflection Detection for Accurate Object Tracking

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Solution Overview

Problem

Existing object detection algorithms struggle in environments with reflective surfaces, leading to issues such as double counting or missing reflections due to the imperfect similarity between reflections and tracked objects, especially in scenarios like city environments with mirrors and glass surfaces.

Innovation Solution

A method and controller that analyze distance ratios and displacement factors of unfiltered object position indicators in a sequence of image frames to identify reflections by comparing normalized sizes and movements, determining the object with a lower detection score as the reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If object detection algorithms are used in environments with reflective surfaces, then objects can be detected, but reflections are either double-counted or missed due to imperfect similarity between reflections and tracked objects

Engineering Contradiction:
Improveobject detection accuracyVSAvoidreflection identification precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by calculating normalized size and normalized movement for each detected object before final identification. By pre-computing these characteristics and storing them for comparison, the system can efficiently identify reflections without reprocessing the entire detection data, thus improving reflection identification precision while maintaining detection accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by comparing the normalized size and normalized movement of detected objects against each other to identify reflections. The detection score is adjusted based on this comparison, creating a feedback loop that refines the identification process. This feedback mechanism allows the system to correctly distinguish between actual objects and reflections, resolving the contradiction between detection accuracy and reflection identification precision.

Inventive Principle:
Principle #23Feedback

2Productivity

If reflections are treated as separate objects, then all objects including reflections can be detected, but the number of detected objects increases leading to double counting

Engineering Contradiction:
Improvedetection coverageVSAvoidnumber of detected objects
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The system merges the detection of actual objects and reflections into a unified processing framework. By calculating normalized size and normalized movement for both actual objects and their reflections using the same algorithms, the system maintains consistent detection coverage while enabling subsequent differentiation. This merging approach ensures that both objects and reflections are detected (maintaining productivity) but allows for later identification and filtering to prevent double counting.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system applies local quality by treating detected objects and reflections differently in the final output based on their identified characteristics. While both are processed through the same detection pipeline (maintaining detection coverage), the system then applies different handling based on whether an object is identified as a reflection through normalized size and movement comparison. This allows the system to maintain high detection coverage while preventing double counting by applying localized differentiation in the output processing stage.

Inventive Principle:
Principle #3Local quality

3Productivity

If detection score threshold is lowered to include reflections, then more objects are detected including reflections, but false positives increase

Engineering Contradiction:
Improvedetection sensitivityVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary calculation of normalized size and normalized movement for all detected objects before final classification. By pre-computing these characteristics, the system can later use them to filter out reflections without needing to lower the detection score threshold. This preliminary action enables the system to maintain high detection sensitivity while using the pre-computed characteristics to ensure high detection accuracy through subsequent filtering.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system extracts the reflection identification task from the main detection process. By separating the detection phase (which uses standard thresholds and detects both objects and reflections) from the identification phase (which uses normalized size and movement comparison to distinguish reflections), the system can maintain high detection sensitivity while preventing false positives through extraction of the reflection discrimination function into a separate processing stage.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS12555377B2Detection of reflection objects in a sequence of image frames
Publication Date: 2026.02.17 AXIS
  • US12555377B2 patent drawing
  • US12555377B2 patent drawing
  • US12555377B2 patent drawing

AI summary

A system and techniques for detecting a reflection of an object in a sequence of image frames. Objects of a given type are detected in the sequence of image frames, and a detection score is determined for each detected object. Distance ratios between unfiltered object position indicators identified for each detected object are determined. A displacement factor is determined for each detected object between a current location of the detected object and a previous location of the detected object. One of the two detected objects which has a lower detection score is a reflection of the other of the two detected objects is determined in response to finding a match between normalized sizes and normalized movements of the detected objects.