Kernel Space Traffic Light Recognition via HSV Binarization

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Solution Overview

Problem

Current traffic light recognition systems face challenges in accurately identifying traffic lights amidst similar objects due to variations in illumination, occlusion, and angle, leading to high false positives and misclassification rates, especially in urban scenarios where GPS errors and hardware installation costs are concerns.

Innovation Solution

A system utilizing a kernelization module to project frames into a kernel space based on luminance and saturation properties, followed by binarization and decision tree analysis to identify candidate blobs, with a classification module using support vector machines for accurate traffic light recognition, reducing false positives and negatives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If vision-based methods using RGB color space and template matching are used for traffic light recognition, then the system can operate with low cost and ubiquitous camera sensors, but the recognition accuracy deteriorates due to sensitivity to illumination variations, view-angle, and weather conditions

Engineering Contradiction:
ImprovecostVSAvoidrecognition accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transforms the input image from RGB color space to HSV color space, changing the parameter representation of colors. This transformation makes the traffic light detection more robust to illumination variations because HSV separates hue (color information) from value (brightness), allowing consistent color recognition under different lighting conditions while maintaining compatibility with standard camera sensors

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an additional processing dimension by applying morphological operations (erosion and dilation) in the spatial domain and using histogram analysis in the color domain. These additional dimensional transformations help separate traffic lights from similar objects like tail lights by analyzing their spatial distribution patterns and color histograms across multiple dimensions

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

2Measurement precision

If GPS information and camera calibration are used to constrain traffic light search region, then detection accuracy improves, but the system complexity and infrastructure requirements increase due to need for pre-mapping and accurate calibration

Engineering Contradiction:
Improvedetection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes the dependency on GPS and pre-mapping infrastructure by implementing a purely vision-based detection system. The method extracts traffic light candidates directly from image processing without requiring external positioning systems, thereby reducing system complexity while maintaining detection accuracy through robust image analysis techniques

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs self-calibration and self-localization by using the camera's intrinsic parameters and the geometric relationships visible in the image itself. Rather than requiring external GPS calibration, the system uses vanishing point detection and perspective transformation to automatically establish the search region based on the captured image geometry

Inventive Principle:
Principle #25Self-service

3Productivity

If geometric features and color space analysis are used for traffic light identification, then the method is computationally efficient, but false positive rate increases due to similarity with tail lights, street lights, and reflections

Engineering Contradiction:
Improveprocessing speedVSAvoidfalse positive rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the image processing into distinct stages: candidate detection using morphological operations, feature extraction using histograms, and classification using decision trees. This segmentation allows efficient processing at each stage while progressively filtering out false positives, maintaining high processing speed through parallelizable operations and early rejection of non-candidate regions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces histogram analysis as an intermediary step between simple color detection and final classification. The histogram acts as a mediator that captures the distribution of colors in candidate regions, providing additional discriminative information to distinguish traffic lights from similar objects while maintaining computational efficiency through histogram-based feature extraction

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11087153B2Traffic light recognition system and method
Publication Date: 2021.08.10 COGNIZANT TECH SOLUTIONS INDIA PVT LTD
  • US11087153B2 patent drawing
  • US11087153B2 patent drawing
  • US11087153B2 patent drawing

AI summary

The present disclosure is directed to a traffic light recognition system and method for advanced driver assistance systems (ADAS) and robust to variations in illumination, partial occlusion, climate, shape and angle at which traffic light is viewed. The solution performs a real time recognition of traffic light by detecting the region of interest, where extracting the region of interest is achieved by projecting the sequence of frames into a kernel space, binarizing the linearly separated sequence of frames, identifying and classifying the region of interest as a candidate representative of traffic light. With the aforesaid combination of techniques used, traffic light can be conveniently recognized from amidst closely similar appearing objects such as vehicle headlights, tail or rear lights, lamp posts, reflections, street lights etc. with enhanced accuracy in real time.