Omnidirectional Image Processing via 3D Polyhedron Mapping

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Solution Overview

Problem

Standard convolutional neural networks (CNNs) face challenges in handling spherical images efficiently, particularly in tasks like semantic segmentation, due to distortion issues when mapping spherical inputs to planar representations, which affects accuracy and computational efficiency.

Innovation Solution

The method involves mapping omnidirectional images to a three-dimensional polyhedron, specifically an icosahedron mesh, and processing them using an orientation-aware convolutional neural network with filters aligned to the polyhedron's reference axis, allowing for efficient convolution operations and weight sharing across the sphere.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If spherical images are mapped to planar representations for processing with standard CNNs, then computational efficiency is improved, but distortion issues occur that reduce segmentation accuracy

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidsegmentation accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent transitions from processing images in 2D planar space to 3D spherical space by mapping omnidirectional images to a spherical coordinate system. This allows the neural network to operate natively in 3D space, avoiding the distortion inherent in 2D projections while maintaining computational efficiency through specialized spherical convolution operations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent explicitly adopts a spherical geometry for representing and processing omnidirectional images. By using a spherical coordinate system and spherical convolution operations, the system naturally handles the curved surface of the sphere, eliminating the need for distortion-prone planar projections while preserving computational tractability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Manufacturing precision

If spherical images are processed directly without mapping to planar representation, then segmentation accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improvesegmentation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter space from Cartesian coordinates used in standard CNNs to spherical coordinates. This involves transforming the convolution operations to work with spherical harmonics and angular coordinates, which reduces computational complexity compared to general 3D processing while maintaining the benefits of spherical representation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical approach of mapping spherical images to planar grids with a mathematical approach using spherical coordinate systems and spherical convolution operations. This substitution eliminates the need for complex mapping transformations while providing a more elegant and computationally efficient solution.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If standard CNNs are used on spherical images, then ease of implementation is maintained, but distortion artifacts reduce processing quality

Engineering Contradiction:
Improveease of implementationVSAvoidprocessing quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the spherical image processing into distinct operational phases: mapping omnidirectional input to spherical coordinates, performing convolution operations in the spherical domain, and projecting results back to planar output. This segmentation allows each phase to be optimized independently, maintaining implementation simplicity while improving overall processing quality.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11341722B2Computer vision method and system
Publication Date: 2022.05.24 KK TOSHIBA
  • US11341722B2 patent drawing
  • US11341722B2 patent drawing
  • US11341722B2 patent drawing

AI summary

A computer vision method for processing an omnidirectional image to extract understanding of a scene, the method comprising:receiving an omnidirectional image of a scene;mapping the omnidirectional image to a mesh on a three-dimensional polyhedron;convert the three dimensional polyhedron into a representation of a neighbourhood structure, wherein the representation of a neighbourhood structure represents vertices of said mesh and their neighbouring vertices; andprocessing the representation of the neighbourhood structure with a neural network processing stage to produce an output providing understanding of the scene,wherein the neural network processing stage comprising at least one module configured to perform convolution with a filter, aligned with a reference axis of the three-dimensional polyhedron.