Stereo Vision Object Recognition for Road Signs

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Solution Overview

Problem

Existing object detection and recognition systems face challenges in accurately identifying road signs in complex images from moving vehicles, due to variations in size, orientation, color, and similarity to other objects, and require large databases for machine learning, which is time-consuming and expensive, and struggle with real-time processing and environmental factors like light intensity.

Innovation Solution

An object detection and recognition system using multiple image capture devices to form stereoscopic representations, isolating objects with range information, and employing pixel mapping, least squares curve fitting, and correlation analysis to identify objects of interest, with templates pre-screened for location, geometry, and color, and utilizing GPS for locale-specific updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If machine learning algorithms with large image databases are used for road sign recognition, then recognition capability is improved, but system cost and time consumption increase

Engineering Contradiction:
Improveroad sign recognition capabilityVSAvoiddatabase acquisition time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system pre-processes and stores road sign templates in a database before actual recognition operations. These templates include various orientations, sizes, and color variations that are prepared in advance, allowing the recognition algorithm to work with pre-organized data rather than requiring large-scale database acquisition during deployment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts key features from road signs such as color information, shape characteristics, and pictogram patterns, and stores only these essential features in the database rather than complete images. This extraction approach significantly reduces database size while maintaining recognition accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If color segmentation is used to isolate objects from background, then object isolation is improved, but reliability decreases due to light intensity and fading variations

Engineering Contradiction:
Improveobject isolation capabilityVSAvoidcolor segmentation accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system applies different processing strategies to different parts of the image based on local characteristics. For road signs, it uses color information combined with shape and position constraints, while for other objects it applies different segmentation criteria. This localized approach improves reliability by adapting to specific regional characteristics rather than using uniform color segmentation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the parameter space by not relying solely on color information but combining it with geometric parameters (shape, size, orientation) and position parameters. This multi-parameter approach compensates for color variations due to lighting and fading, maintaining segmentation reliability under varying environmental conditions.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If single camera systems are used for road sign detection, then device complexity is reduced, but measurement precision deteriorates due to lack of depth information

Engineering Contradiction:
Improvesystem structureVSAvoidobject distance and orientation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system transitions from 2D image analysis to 3D spatial understanding by incorporating depth information through multiple cameras. The stereo vision setup provides parallax-based depth measurement, enabling the system to determine object distance, size, and orientation more accurately without significantly increasing overall system complexity.

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

4Productivity

If real-time processing is implemented for road sign recognition, then productivity is improved, but measurement precision may deteriorate due to processing time constraints

Engineering Contradiction:
Improvereal-time processing speedVSAvoidobject recognition accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The recognition system is divided into multiple independent modules: object detection, feature extraction, template matching, and verification. Each module processes specific aspects of recognition independently and in parallel where possible, reducing overall processing time while maintaining accuracy through systematic verification steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements a multi-stage recognition process where not all processing steps are applied to every object. High-confidence detections from preliminary stages may skip verification steps, while ambiguous cases receive full processing. This selective application of processing intensity maintains real-time performance while ensuring accuracy for critical cases.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS8131018B2Object detection and recognition system
Publication Date: 2012.03.06 JOYSON SAFETY SYSTEMS ACQUISITION LLC
  • US8131018B2 patent drawing
  • US8131018B2 patent drawing
  • US8131018B2 patent drawing

AI summary

An object recognition system is provided including at least one image capturing device configured to capture at least one image, wherein the image includes a plurality of pixels and is represented in an image data set, an object detection device configured to identify a plurality of pixels corresponding to objects from the at least one image, wherein an object includes a plurality of pixels and is represented in an object data set, wherein the object data set includes a set of features corresponding to each pixel in the object, and an image recognition device configured to recognize objects of interest present in an object by image correlation against a set of template images to recognize an object as one of the templates.