Monocular Camera Object Detection Using Homographies Near the Epipole

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Solution Overview

Problem

Current vehicle detection systems based on classification methods struggle with new vehicle designs and changing structures, leading to reduced performance, especially in recognizing objects near the epipole, where triangulation is imprecise and relative speed is unknown, causing errors in detecting collisions with stationary or moving vehicles.

Innovation Solution

A method that records a sequence of images from a monocular vehicle camera, determines corresponding features, assigns them to levels in space based on orientations (floor, rear wall, side wall planes), calculates homographies to determine movement, and detects dynamic objects by analyzing the movement of these levels, allowing for accurate segmentation and differentiation between static and dynamic objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If classification-based methods are used for vehicle recognition, then known vehicle designs can be recognized, but new vehicle designs and changing bodywork lead to significantly reduced system performance

Engineering Contradiction:
Improvevehicle recognition accuracyVSAvoidability to recognize new vehicle designs
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from classification-based recognition to geometry-based recognition using homography parameters. By changing the recognition parameters from categorical labels to geometric transformations (homography matrices derived from feature correspondences), the system can recognize any vehicle structure without prior training data, thus improving adaptability while maintaining reliability through mathematical rigor.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the machine learning classification system with a geometric computation system based on homography. This substitution eliminates the need for training data and classification models, allowing the system to handle new vehicle designs through pure geometric reasoning based on feature point correspondences between images.

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

2Measurement precision

If triangulation is used for objects near the epipole, then object positions can be determined, but triangulation is imprecise and relative speed is unknown

Engineering Contradiction:
Improveobject position accuracyVSAvoidrelative speed information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the image plane into different regions based on homography analysis. By dividing the scene into regions with different motion characteristics (static background vs. moving objects), the system can separately analyze each region's homography parameters to determine both position and speed, overcoming the limitations of global triangulation near the epipole.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds the temporal dimension by analyzing homography changes across multiple image frames. By examining how homography parameters evolve over time, the system can derive both position and relative speed information, transforming a 2D position estimation problem into a 3D spatio-temporal analysis that recovers speed information lost in static triangulation.

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

3Device complexity

If monocular camera is used for object detection, then system complexity is reduced, but objects close to the epipole can only be triangulated imprecisely

Engineering Contradiction:
Improvecamera system complexityVSAvoidtriangulation accuracy near epipole
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes from using raw pixel coordinates for triangulation to using homography transformation parameters. By representing scene geometry through homography matrices (which encode position, scale, and orientation), the system achieves more stable and accurate measurements near the epipole while maintaining monocular simplicity, as homography parameters are less sensitive to epipolar geometry singularities.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3520025B1Detection and validation of objects from sequential images of a camera using homograpies
Publication Date: 2024.11.06 CONTINENTAL AUTONOMOUS MOBILITY GERMANY GMBH
  • EP3520025B1 patent drawingFigure 1~2
  • EP3520025B1 patent drawingFigure 3a~4
  • EP3520025B1 patent drawingFigure 5a~5d

AI summary

The invention relates to a method and to a device for identifying objects from images from a camera and can be used in particular in camera-based driver assistance systems. The method for detecting objects from a series of images from a vehicle camera comprises the following steps: a) capturing a series of images by means of the vehicle camera, b) determining motion of planes in space, wherein the planes are determined by means of an association of adjacent, corresponding features in at least two consecutive images, and e) identifying dynamic objects on the basis of the determined motion of a plane. According to a preferred embodiment, the method comprises the following step: c) computing homographs for adjacent corresponding features for determining the plurality of planes; and/or d) associating adjacent corresponding features with a bottom plane, a back wall plane or a side wall plane. Because the method according to the invention can be designed to be very fast, generic object detection or scene interpretation is possible for nearly the whole image in real time.