Vehicle Signal Light State Detection Using Temporal Classifiers

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing techniques fail to accurately identify the ON and OFF states of a vehicle's signal lights from images, especially when the cycle and duration of these states are indefinite, making it difficult for automated driving systems to predict vehicle motion effectively.

Innovation Solution

An apparatus and method using a processor to input time series images into a first classifier to detect vehicle regions, and then into a second classifier with a recursive structure or performing convolution operations in the temporal direction to calculate confidence scores for candidate states of the signal light, allowing accurate identification of ON and OFF states based on transition information and confidence scores.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional object detection techniques are used to detect signal light states, then the detection process is simple, but the identification accuracy of signal light ON/OFF states is insufficient

Engineering Contradiction:
Improveidentification accuracy of signal light statesVSAvoidclassifier structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection system is divided into two specialized classifiers: a first classifier for detecting vehicle presence and a second classifier for detecting signal light states. This segmentation allows each classifier to focus on its specific task, improving overall detection accuracy while maintaining manageable complexity through functional division.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second classifier introduces a temporal dimension by processing time-series images sequentially and incorporating previous detection results. This transforms the detection from a single-frame static analysis to a multi-frame dynamic analysis, significantly improving signal light state identification accuracy by considering temporal continuity and state transitions.

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

2Measurement precision

If single-frame image detection is used, then the processing speed is fast, but the accuracy of identifying signal light states with indefinite cycles is insufficient

Engineering Contradiction:
Improveaccuracy of signal light state identificationVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary detection using the first classifier to identify vehicle regions before applying the more computationally intensive second classifier. This preliminary filtering reduces the amount of data requiring detailed analysis, maintaining processing efficiency while enabling accurate multi-frame temporal analysis for signal light state identification.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback from previous detection results into the current frame analysis. The second classifier uses the detected signal light states from previous frames to inform current state determination, allowing the system to leverage temporal patterns and improve accuracy for signal lights with indefinite cycles while maintaining efficient processing through intelligent reuse of historical data.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11900690B2Apparatus, method, and computer program for identifying state of signal light, and controller
Publication Date: 2024.02.13 TOYOTA JIDOSHA KK
  • US11900690B2 patent drawing
  • US11900690B2 patent drawing
  • US11900690B2 patent drawing

AI summary

An apparatus for identifying the state of a signal light includes a processor configured to input time series images into a first classifier to detect object regions each including a vehicle equipped with a signal light in the respective images, the first classifier having been trained to detect the vehicle; chronologically input characteristics obtained from pixel values of the object regions detected in the respective images into a second classifier to calculate confidence scores of possible candidate states of the signal light of the vehicle, the second classifier having a recursive structure or performing a convolution operation in a temporal direction; and identify the state of the signal light, based on the preceding state of the signal light, information indicating whether transitions between the candidate states of the signal light are allowed, and the confidence scores of the respective candidate states.