Stereo Reconstruction Using Homography Fitting

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Solution Overview

Problem

Traditional stereo reconstruction methods face limitations in accuracy and processing speed, particularly in photo-consistency optimization and back-projection of 3D patches into image planes, which are computationally intensive and time-consuming.

Innovation Solution

The implementation of homography fitting to convert photo-consistency measures into an implicit function of pixel coordinates, using an inverse compositional image alignment process to derive analytical gradients, and optimizing correspondence points for improved accuracy and reduced computation time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If traditional stereo reconstruction methods are used, then processing speed is slow, but accuracy can be maintained

Engineering Contradiction:
Improveprocessing speedVSAvoidcomputation time
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent segments the stereo reconstruction process into distinct modules: image rectification, feature point detection, matching, and 3D reconstruction. This segmentation allows each module to be optimized independently, with feature point detection focusing on key locations rather than processing entire images, thereby significantly reducing computation time while maintaining accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by selecting and processing only salient feature points rather than all pixels in the image. By identifying and matching only the most informative feature points (corners, edges, distinctive patterns), the system achieves accurate stereo reconstruction with substantially reduced computational load compared to full-image processing.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If photo-consistency optimization is performed, then accuracy improves, but computation time increases

Engineering Contradiction:
ImproveaccuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies local quality by performing photo-consistency optimization only in local regions around matched feature points rather than across the entire image. This localized approach maintains the accuracy benefits of photo-consistency verification while dramatically reducing the computational scope to only relevant local neighborhoods.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system performs partial photo-consistency optimization by applying it selectively to matched feature point pairs rather than all possible pixel correspondences. This partial application maintains measurement precision for critical feature points while avoiding the computational burden of exhaustive optimization.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If back-projection of 3D patches is performed, then reconstruction detail improves, but processing complexity increases

Engineering Contradiction:
Improvereconstruction detailVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the back-projection operation to reconstruct 3D geometry only at matched feature point locations rather than generating dense 3D meshes for entire image regions. This segmented approach produces accurate 3D point clouds at key locations with minimal computational complexity, avoiding the burden of full patch-based back-projection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs partial back-projection by computing 3D coordinates only for matched feature points rather than back-projecting all pixels or large image patches. This selective back-projection achieves sufficient reconstruction detail for stereo vision applications while keeping processing complexity manageable.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS9652849B2Techniques for rapid stereo reconstruction from images
Publication Date: 2017.05.16 TAHOE RES LTD
  • US9652849B2 patent drawing
  • US9652849B2 patent drawing
  • US9652849B2 patent drawing

AI summary

Stereo image reconstruction techniques are described. An image from a root viewpoint is translated to an image from another viewpoint. Homography fitting is used to translate the image between viewpoints. Inverse compositional image alignment is used to determine a homography matrix and determine a pixel in the translated image.