Cascaded Machine Learning and Visual Tracking for 2D Feature Estimation

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Solution Overview

Problem

Current feature tracking methods in computer vision face a trade-off between accuracy and speed, with conventional visual tracking providing high accuracy but high computational cost, and machine learning-based methods offering speed but lower accuracy, and existing combinations requiring specific targets for initial detection, limiting their applicability.

Innovation Solution

A cascaded approach that uses a machine learning technique to provide initial estimates of feature points and displacements in 2D images, followed by a visual tracking technique for refined estimates, allowing every pixel to be a potential feature without the need for initial detection, thereby combining the speed of machine learning with the accuracy of visual tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional visual tracking methods are used, then measurement precision is improved, but productivity deteriorates due to high computational cost limiting the number of features tracked

Engineering Contradiction:
Improvetracking accuracyVSAvoidnumber of features tracked
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the tracking process into two distinct stages: a coarse tracking stage using machine learning methods to handle a large number of features, and a refined tracking stage using conventional visual tracking methods to improve precision on selected features. This segmentation allows the system to process many features efficiently while maintaining high accuracy where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different quality levels of tracking to different regions or features. Machine learning-based coarse tracking is applied globally to all features, while conventional visual tracking with higher precision is applied locally to selected features of interest, optimizing the balance between overall productivity and local measurement precision.

Inventive Principle:
Principle #3Local quality

2Productivity

If machine learning-based tracking methods are used, then productivity is improved through real-time tracking capability, but measurement precision deteriorates due to lower accuracy

Engineering Contradiction:
Improvereal-time tracking speedVSAvoidtracking accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary selection mechanism that bridges machine learning tracking and conventional visual tracking. The machine learning stage identifies candidate features, and a selection process filters these candidates for refined tracking, creating a smooth transition between the two methods and allowing the system to leverage the speed of ML while correcting its precision limitations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If detection-based methods are used, then measurement precision is improved for specific targets, but adaptability deteriorates because specific targets are required for initial detection

Engineering Contradiction:
Improvefeature detection accuracyVSAvoidapplicability to individual pixels
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal tracking framework where every pixel can potentially be a feature, eliminating the need for target-specific detection. The machine learning-based coarse tracking stage processes all pixels uniformly, and the selection mechanism adaptsively chooses which pixels to refine, making the system universally applicable to any image content without requiring predefined target knowledge.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS10733474B2Method for 2D feature tracking by cascaded machine learning and visual tracking
Publication Date: 2020.08.04 SONY GROUP CORP
  • US10733474B2 patent drawing
  • US10733474B2 patent drawing
  • US10733474B2 patent drawing

AI summary

A method for 2D feature tracking by cascaded machine learning and visual tracking comprises: applying a machine learning technique (MLT) that accepts as a first MLT input first and second 2D images, the MLT operating on the images to provide initial estimates of a start point for a feature in the first image and a displacement of the feature in the second image relative to the first image; applying a visual tracking technique (VT) that accepts as a first VT input the initial estimates of the start point and the displacement, and that accepts as a second VT input the two 2D images, processing the first and second inputs to provide refined estimates of the start point and the displacement; and displaying the refined estimates in an output image.