Road Sign Recognition via Spatial Zone Prediction

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Solution Overview

Problem

Current road sign recognition systems require high computing effort and suffer from insufficient robustness due to the need to search the entire image for potential road signs, which increases processing time and reduces accuracy.

Innovation Solution

The method determines relevant spatial zones in the camera's field of view based on known object positions and road course, calculates image zones on the image plane, and predicts the size of objects within these zones using camera parameters, allowing for focused search areas and reduced computing time while enhancing robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire image is searched for potential road signs using feature extraction and classification, then comprehensive detection is achieved, but computing effort and computing time increase significantly

Engineering Contradiction:
Improvedetection completenessVSAvoidcomputing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The image is divided into multiple zones based on spatial probability, with only high-probability zones subjected to full feature extraction and classification. This segmentation approach maintains detection completeness in critical areas while reducing overall computing effort by excluding low-probability regions from intensive processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing qualities are applied to different image regions: high-probability zones receive full classification and feature extraction, while low-probability zones receive reduced or no processing. This local quality differentiation optimizes the balance between detection reliability and computing efficiency.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If feature extraction and classification are performed on all image candidates, then accurate road sign identification is achieved, but computing time increases

Engineering Contradiction:
Improverecognition accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

Spatial probability zones are pre-calculated based on road geometry and camera parameters before actual road sign detection. This preliminary action enables the system to quickly identify which regions warrant full classification processing, thereby reducing overall processing time while maintaining accuracy in high-probability areas.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Full feature extraction and classification are applied only to high-probability zones rather than the entire image. This partial action approach achieves sufficient recognition accuracy for critical regions while significantly reducing computing time by excluding low-probability areas from intensive processing.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the search area covers the entire field of view, then no road signs are missed, but the computing effort increases

Engineering Contradiction:
Improvedetection robustnessVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The field of view is segmented into high-probability and low-probability zones based on spatial reasoning about road geometry and typical road sign locations. This segmentation allows the system to focus computational resources on high-probability zones, reducing overall computational complexity while maintaining robustness through comprehensive coverage of critical areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the search strategy by changing the effective search parameter (processing intensity) based on spatial probability. High-probability zones receive full processing with all feature extraction and classification, while low-probability zones receive reduced processing, thereby reducing computational complexity while maintaining detection robustness.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8050460B2Method for recognition of an object
Publication Date: 2011.11.01 APTIV TECHNOLOGIES AG
  • US8050460B2 patent drawing
  • US8050460B2 patent drawing
  • US8050460B2 patent drawing

AI summary

The invention relates to a method for the prediction of the size to be expected of the image of a stationary object associated with a road in a picture of the environment in the field of view of a camera device which is in particular arranged at a motor vehicle and which has an image plane including image elements, wherein at least one relevant spatial zone from the field of view of the camera device is determined; wherein boundaries of the calculated projection onto the image plane of the at least one relevant spatial zone are determined in order to determine at least one relevant image zone; wherein a directional beam is determined for each of the image elements in the at least one relevant image zone, said directional beam including those spatial points from the field of view which would be projected onto the respective image element on a projection onto the image plane; and wherein at least one value for the size to be expected of the image of a road sign in the respective image element is determined for each of the image elements in the relevant image zone.