Railroad Light Activation Detection for Autonomous Vehicle Control

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Solution Overview

Problem

Autonomous vehicles face challenges in accurately detecting the status of railroad lights, leading to potential unsafe decisions due to false positives or negatives, as existing sensor technologies may misinterpret the illumination status of railroad lights, especially under adverse conditions like low sunlight.

Innovation Solution

The system determines the illumination status of railroad lights by analyzing image data using processors, categorizing by color and shape, and determining brightness levels, with a sliding window correlation filter or convolutional neural network, to calculate a confidence level indicating the likelihood of the light being active, which adjusts the vehicle's trajectory and control actions accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing sensor technologies (LIDAR, radar, cameras) are used to detect railroad lights, then the vehicle can perceive the environment, but false positives or negatives occur leading to unsafe decisions

Engineering Contradiction:
Improvedetection accuracyVSAvoidillumination status detection
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The detection system segments the railroad light detection task into multiple independent analysis components: image capture, color classification, shape verification, brightness threshold evaluation, and temporal pattern recognition. Each component processes specific features separately and combines results to achieve more reliable detection than any single sensor or method could provide alone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system introduces an intermediary confidence level metric that mediates between raw sensor data and vehicle control decisions. This confidence level serves as a buffer that filters out false positives/negatives by requiring multiple corroborating features (correct color, proper shape, appropriate brightness threshold, expected temporal pattern) before triggering a definitive detection state, thereby improving both reliability and measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the vehicle responds quickly to detected railroad lights, then safety is improved, but false detections cause unsafe maneuvers such as hard braking

Engineering Contradiction:
Improvesafe maneuveringVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The system performs preliminary verification of multiple light features (color, shape, brightness, temporal pattern) before committing to a detection decision. By pre-establishing confidence thresholds and requiring corroborating evidence across multiple detection dimensions, the system prepares the confidence level metric in advance, enabling quick response only when the preliminary verification is satisfied, thus avoiding unsafe maneuvers from false detections while maintaining rapid response to genuine threats.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The confidence level metric provides continuous feedback between the detection system and vehicle control system. This feedback mechanism allows the vehicle to respond appropriately to detection confidence: high confidence triggers immediate safety maneuvers, while low or uncertain confidence maintains normal operation. This feedback loop enables differentiated response speeds based on detection reliability, ensuring quick action only when necessary and avoiding unsafe maneuvers from false positives.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11249487B2Railroad light detection
Publication Date: 2022.02.15 WAYMO LLC
  • US11249487B2 patent drawing
  • US11249487B2 patent drawing
  • US11249487B2 patent drawing

AI summary

The technology relates to controlling a vehicle based on a railroad light's activation status. In one example, one or more processors receive images of a railroad light. The one or more processors determine, based on the images of the railroad light, the illumination status of a pair of lights of the railroad light over a period of time as the vehicle approaches the railroad light. The one or more processors determine based on the illumination status of the pair of lights, a confidence level, wherein the confidence level indicates the likelihood the railroad light is active. The vehicle is controlled as it approaches the railroad light based on the confidence level.