3D Shape Estimation via Multi-View Silhouette Projection

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Solution Overview

Problem

Existing methods for reconstructing a three-dimensional shape of an object from multi-viewpoint images, such as the volume intersection method, require significant computational resources, especially when dealing with large spaces or high-resolution images, leading to increased calculation burdens.

Innovation Solution

The proposed solution involves an image processing apparatus that acquires silhouette image data from multiple viewpoints, generates low-resolution data, and calculates intersection intervals of line segments with the object by projecting them onto both low-resolution and high-resolution silhouette data, thereby reducing the computational load by limiting the processing to necessary regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the volume intersection method is used to reconstruct three-dimensional shape from multi-viewpoint images, then the shape estimation accuracy is improved, but the calculation amount increases significantly when the space to be measured is large

Engineering Contradiction:
Improveshape estimation accuracyVSAvoidcalculation amount
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the measurement space into a coarse grid structure where only certain regions (those intersected by rays from silhouette boundaries) are processed in detail. This divides the large space into manageable segments, reducing the overall calculation amount while maintaining shape estimation accuracy in the regions of interest.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing qualities to different regions: high-resolution processing is applied only to regions where rays intersect silhouette boundaries (potential object regions), while other regions use lower-resolution or pre-defined grid data. This local differentiation reduces calculation amount without compromising the accuracy of the actual object shape estimation.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the contour of silhouette is extracted to limit ray intersection calculation, then the calculation amount is reduced, but the calculation amount increases if the resolution of input image is high

Engineering Contradiction:
Improvecalculation amountVSAvoidsilhouette resolution
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent extracts only the essential silhouette boundary information from high-resolution images, rather than processing the entire high-resolution image data. By taking out just the contour information needed for ray intersection testing, the calculation amount is reduced while maintaining the precision needed for accurate shape estimation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a hybrid approach where silhouette extraction is performed at reduced resolution for most rays, but full-resolution silhouette data is used for critical rays that define object boundaries. This partial application of high-resolution processing reduces overall calculation while maintaining necessary precision.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS10325378B2Image processing apparatus, image processing method, and non-transitory storage medium
Publication Date: 2019.06.18 CANON KK
  • US10325378B2 patent drawing
  • US10325378B2 patent drawing
  • US10325378B2 patent drawing

AI summary

An image processing apparatus includes: an acquisition unit configured to acquire pieces of silhouette image data of an object viewed from multiple different viewpoints; a generation unit configured to generate, from the pieces of silhouette image data, pieces of low-resolution data representing images with a resolution lower than the pieces of silhouette image data; and an estimation unit configured to, by performing, for a plurality of line segments in space containing the object, processing in which, after a line segment in the space is projected onto a piece of low-resolution data to calculate a first intersection of the line segment with the object, the line segment is projected onto a piece of silhouette image data to calculate a second intersection of the line segment with the object, calculate intervals over which the plurality of line segments intersect the object and estimate a shape of the object.