3D Shape Reconstruction Using Reliability-Based Voxel Correction

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Solution Overview

Problem

Existing methods for generating three-dimensional shapes of objects using multi-viewpoint images can result in inaccurate reconstructions due to insufficient or unevenly distributed camera viewpoints, leading to excessive inflation or incomplete shape generation.

Innovation Solution

An image processing apparatus and method that selectively retains and corrects geometric data by determining the reliability of camera viewpoints, using a threshold value to ensure accurate shape reconstruction by deleting or applying approximation models to voxels with insufficient valid cameras, and interactively adjusting parameters through a graphical user interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complementation method is used to generate three-dimensional shape of partially lacking object, then the lacking part can be filled, but the shape may be excessively inflated and different from real shape

Engineering Contradiction:
Improveaccuracy of three-dimensional shape reconstructionVSAvoidfidelity of reconstructed shape
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by differentiating between reliable and unreliable regions in the three-dimensional shape data. It identifies portions with insufficient valid cameras and applies different processing strategies: deleting unreliable portions and using approximation models only where necessary, while preserving accurate regions. This localized approach ensures that high-fidelity regions maintain their precision while low-fidelity regions are appropriately handled, resolving the contradiction between completeness and accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of traditionally adding missing parts through complementation (which causes inflation), the patent inverts the approach by selectively deleting unreliable portions and using approximation models only as a fallback. This inversion prevents excessive inflation by removing the problematic complementation step and replacing it with a deletion-and-approximation strategy that maintains shape fidelity.

Inventive Principle:
Principle #13The other way round (Inversion)

2Productivity

If Silhouette Volume Intersection is used with lower number of viewpoints, then processing speed is maintained, but the generated shape may be excessively inflated

Engineering Contradiction:
Improveprocessing speed of shape generationVSAvoidaccuracy of three-dimensional shape
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by evaluating each portion of the three-dimensional shape data based on the number of valid cameras that captured it. Regions with sufficient viewpoints are processed with high accuracy using Silhouette Volume Intersection, while regions with insufficient viewpoints are identified and handled differently through deletion or approximation models. This localized differentiation maintains processing speed while improving overall shape accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies partial action by selectively applying approximation models only to portions with insufficient valid cameras, rather than applying complementation globally. This partial application of approximation prevents excessive inflation in well-captured regions while providing necessary filling only where viewpoints are insufficient, thus maintaining both speed and accuracy.

Inventive Principle:
Principle #16Partial or excessive action

3Area of stationary object

If valid cameras are distributed unevenly, then coverage of object is achieved, but the reconstructed shape lacks fidelity in certain regions

Engineering Contradiction:
Improvecoverage of object by camerasVSAvoidfidelity of reconstructed shape
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent addresses uneven camera distribution by applying local quality assessment to each portion of the object. It identifies regions where valid cameras are insufficient and handles them differently from well-covered regions. Approximation models are applied selectively to under-covered portions, ensuring that coverage is maintained while fidelity is preserved in well-captured areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses parameter changes by introducing a threshold for the number of valid cameras required for reliable reconstruction. Portions exceeding this threshold are processed with high fidelity, while those below the threshold trigger approximation model application. This parameter-based differentiation resolves the contradiction between coverage and fidelity by adapting processing quality to local camera distribution.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3309750B1Image processing apparatus and image processing method
Publication Date: 2024.01.17 CANON KK
  • EP3309750B1 patent drawingFigure 1~2
  • EP3309750B1 patent drawingFigure 3
  • EP3309750B1 patent drawingFigure 4A~4B

AI summary

An image processing apparatus generating geometric data of an object includes an obtaining unit configured to obtain a plurality of images of the object, each image captured from different viewpoints, a generating unit configured to generate geometric data of the object from the images obtained by the obtaining unit, and a correcting unit configured to correct the geometric data based on a reliability of at least a part of the geometric data generated by the generating unit.