Stop Line Detection With Crosswalk-Depth Search Limits

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Solution Overview

Problem

Conventional stop line detection systems often erroneously detect lines other than actual stop lines, such as bus stop area division lines, due to their proximity and similarity in appearance, leading to inaccurate navigation.

Innovation Solution

The apparatus sets a stop line search area extending from the crosswalk to the vehicle side with a depth less than twice the crosswalk depth, uses a nearby traffic signal to define an intersection area, and employs units to detect crosswalks and road markings to accurately set the search area, avoiding erroneous detections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the stop line search area is extended to cover a large distance from the crosswalk, then the detection coverage is improved, but erroneous detection of non-stop lines increases

Engineering Contradiction:
Improvestop line search area coverageVSAvoidstop line detection accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the depth of the stop line search area based on the detected crosswalk depth. Specifically, the search area depth is set to be less than twice the crosswalk depth, creating an adaptive parameter relationship that maintains detection coverage while preventing erroneous detections of distant lines.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by creating a focused search region with specific depth constraints around the crosswalk area. Instead of uniformly searching the entire road ahead, the system concentrates the search within a localized area defined by the crosswalk dimensions, improving precision in the critical detection zone.

Inventive Principle:
Principle #3Local quality

2Length of stationary object

If the stop line search area depth is increased to detect stop lines farther from the crosswalk, then the detection range is improved, but false positive detections of bus stop lines and other markings increase

Engineering Contradiction:
Improvesearch area depthVSAvoiddetection reliability
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent changes the parameter of search area depth by establishing a specific relationship with crosswalk depth (less than twice the crosswalk depth). This parameter constraint ensures the search area extends far enough to capture actual stop lines while being limited enough to exclude bus stop lines and other non-stop line markings that appear farther away.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the crosswalk depth is used as a reference to set the search area depth, then the detection precision is improved, but the system complexity increases

Engineering Contradiction:
Improvestop line detection precisionVSAvoidsearch area setting complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses parameter changes by establishing a simple mathematical relationship (search area depth < 2 × crosswalk depth) that directly links two detectable parameters. This approach improves precision through parameter correlation while maintaining relatively simple system complexity, as both crosswalk depth and search area depth can be determined through standard image processing.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4246456B1Stop line detection apparatus
Publication Date: 2025.10.22 TOYOTA JIDOSHA KK
  • EP4246456B1 patent drawingFigure 1
  • EP4246456B1 patent drawingFigure 2
  • EP4246456B1 patent drawingFigure 3

AI summary

A stop line detection apparatus recognizes a boundary line of a lane on which the host vehicle travels, and detect a stop line at an intersection in front of the host vehicle. The apparatus sets an intersection area corresponding to the intersection in the road on which the host vehicle travels on the basis of a captured image by a front camera of the host vehicle, detects a crosswalk in the intersection area, a stop line search area setting unit configured to set a stop line search area extending from the crosswalk toward a front side in the lane on which the host vehicle travels, and performs stop line detection in the stop line search area. A depth of the stop line search area in an extending direction of a traveling lane is smaller than twice a depth of the crosswalk.