Monocular Obstacle Detection Using Planar Homography

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Solution Overview

Problem

Current obstacle detection systems for autonomous vehicles are complex and costly, requiring multiple sensors and computational resources, and struggle with real-time deployment due to iterative processing and feature extraction requirements, especially in complex scenes.

Innovation Solution

A system utilizing a single monocular camera to detect obstacles through planar homography and self-supervised scene structure understanding, where a deep neural network predicts a scene structure map from image frames, enabling obstacle detection with minimal sensors and reduced computational intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors and iterative processing methods are used for obstacle detection, then detection accuracy is improved, but device complexity and computational costs increase

Engineering Contradiction:
Improveobstacle detection accuracyVSAvoidsensor and processing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes unnecessary components from the obstacle detection system. Instead of using multiple sensors (cameras, LIDAR, radar), the invention achieves accurate obstacle detection using only a single monocular camera by extracting geometric relationships through planar homography and residual flow computation, thereby eliminating redundant sensors and reducing system complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a virtual copy of the road surface geometry through planar homography transformation. By warping the first image frame to align with the second frame using homography, the system creates a virtual representation of the road plane, allowing obstacle detection through comparison without requiring physical multiple sensors

Inventive Principle:
Principle #26Copying

2Measurement precision

If iterative feature extraction and matching algorithms are used, then obstacle detection capability is improved, but processing speed and real-time performance deteriorate

Engineering Contradiction:
Improveobstacle detection capabilityVSAvoidreal-time processing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary computation of planar homography parameters from detected feature points before the actual obstacle detection process. By pre-computing the homography matrix H that describes the geometric transformation between frames, the system prepares the road surface alignment in advance, enabling faster real-time obstacle detection without iterative processing during runtime

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical iterative feature matching process with a direct geometric computation approach. Instead of iteratively extracting features and matching them across frames, the system uses planar homography to directly compute the geometric relationship between frames, substituting iterative mechanical processing with a closed-form mathematical solution that achieves real-time performance

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

3Measurement precision

If stereo cameras and depth images are used for obstacle segmentation, then segmentation accuracy is improved, but hardware cost and system complexity increase

Engineering Contradiction:
Improveobstacle segmentation accuracyVSAvoidsensor configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the single camera system to self-generate depth and geometric information through computational methods. By computing planar homography and residual flow from monocular image sequences, the system self-produces the depth cues and geometric relationships that would traditionally require stereo cameras, eliminating the need for additional sensors while maintaining segmentation accuracy

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the parameter representation from direct depth measurements (requiring stereo cameras) to homography parameters and residual flow vectors that can be computed from monocular sequences. By transforming the problem into the homography parameter space, the system achieves obstacle segmentation using only a single camera, fundamentally changing the hardware requirements

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11830160B2Object detection using planar homography and self-supervised scene structure understanding
Publication Date: 2023.11.28 NVIDIA CORP
  • US11830160B2 patent drawing
  • US11830160B2 patent drawing
  • US11830160B2 patent drawing

AI summary

In various examples, a single camera is used to capture two images of a scene from different locations. A trained neural network, taking the two images as inputs, outputs a scene structure map that indicates a ratio of height and depth values for pixel locations associated with the images. This ratio may indicate the presence of an object above a surface (e.g., road surface) within the scene. Object detection then can be performed on non-zero values or regions within the scene structure map.