Traffic Light Phase Detection Using Color Saturation Analysis

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for detecting traffic light phases in motor vehicles face challenges such as glare, reflections, poor contrast, steep viewing angles, and partial masking, which hinder accurate recognition of traffic light phases.

Innovation Solution

An apparatus comprising an image sensor, segmentation, and computer devices that determine traffic light phases by analyzing maximum color saturation and brightness in defined image regions, using the HSV color space and considering contrast and camera performance, to accurately identify red, amber, and green signals even at unfavorable angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional image evaluation methods are used to detect traffic light phases, then the system is simple to implement, but the detection accuracy deteriorates due to glare, reflections, poor contrast, steep viewing angles, and partial masking

Engineering Contradiction:
Improvetraffic light phase detection accuracyVSAvoidimage processing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The image processing is divided into distinct segments: image acquisition, segmentation to identify signal lamp regions, evaluation to determine color saturation and brightness, and decision-making to establish traffic light phase. This segmentation allows each component to be optimized independently, improving detection accuracy while managing system complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system evaluates multiple parameters including color saturation, brightness, contrast values, and light conditions rather than relying on a single parameter. By changing and comparing multiple parameters simultaneously, the system achieves more accurate traffic light phase detection even under challenging conditions like glare and reflections

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If the vehicle stops directly at the stop line to capture traffic light images, then the timing is optimal, but the viewing angle becomes steep causing poor image quality

Engineering Contradiction:
Improvetime to detect traffic light phaseVSAvoidimage quality at steep viewing angle
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The system compensates for steep viewing angles by evaluating multiple parameters including contrast values and light conditions alongside color saturation and brightness. This multi-parameter approach maintains detection accuracy even when the viewing angle is unfavorable, allowing the vehicle to stop at the optimal position without sacrificing image quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from multiple image evaluation parameters to adjust and confirm traffic light phase detection. By continuously evaluating contrast, brightness, and color saturation, the system can verify detections even under suboptimal viewing conditions, reducing the need for re-capturing images

Inventive Principle:
Principle #23Feedback

3Reliability

If standard brightness evaluation is used for traffic light detection, then the processing is simple, but the reliability deteriorates due to reflections of extraneous light

Engineering Contradiction:
Improvetraffic light phase recognition reliabilityVSAvoidimage evaluation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system transitions from evaluating only brightness to evaluating both color saturation and brightness simultaneously. This parameter change allows the system to distinguish true traffic light signals from reflections, as reflected light typically has different color saturation characteristics than direct traffic light signals

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system utilizes color space analysis (HSV or similar) to evaluate the color characteristics of detected regions. By analyzing color saturation and hue in addition to brightness, the system can reliably identify traffic light phases even when reflections are present, as the color information provides additional verification

Inventive Principle:
Principle #32Color changes

Data Source

PatentUS11068729B2Apparatus and method for detecting a traffic light phase for a motor vehicle
Publication Date: 2021.07.20 CONTI TEMIC MICROELECTRONIC GMBH
  • US11068729B2 patent drawing
  • US11068729B2 patent drawing

AI summary

An apparatus for detecting a traffic light phase for a motor vehicle, includes: an image sensor device (10), configured to capture an image of a traffic light and to provide the image as image data; a segmentation device (20) configured to define at least one partial region of the captured image and to assign it to at least one signal lamp of the traffic light; a scaling device (30), configured to determine a maximum color saturation and/or a maximum brightness in the at least one partial region; and a computer device (40) configured to determine a signal status of the traffic light based on the maximum color saturation and/or the maximum brightness.