Hierarchical Bicyclist Detection Using Synthetic Training Data

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Solution Overview

Problem

Current object detection systems face challenges in detecting bicyclists due to limited training sets, complex annotation processes, and slow detection speeds, making them unsuitable for real-time applications, especially in vehicle systems where bicyclists' variations and motion blur complicate recognition.

Innovation Solution

A method using a hierarchical classifier system that employs both linear and non-linear classifiers, where a target image is initially classified with a linear classifier, and if the error value exceeds a threshold, it is re-classified using a non-linear classifier, leveraging a positive training image generation module and detection module to generate and annotate 2D images of bicyclists for training, and a detection module that extracts HOG features to determine the presence of bicyclists in real-time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a non-linear classifier is used to improve detection accuracy for bicyclists, then detection precision is improved, but processing time increases and real-time capability is lost

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The detection system is segmented into two stages: a linear classifier for rapid initial screening and a non-linear classifier for accurate verification. This segmentation allows the system to maintain real-time speed for common cases while achieving high accuracy only when needed, resolving the contradiction between speed and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies the complex non-linear classifier only partially - specifically only when the linear classifier indicates uncertainty or when detection confidence is insufficient. This partial application of computational resources maintains real-time capability for most cases while providing high accuracy when necessary.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If manual annotation of training images is performed to ensure data quality, then training data accuracy is improved, but time consumption increases

Engineering Contradiction:
Improvetraining data accuracyVSAvoidannotation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system uses self-generated synthetic training data where the rendering module automatically creates annotated images of bicyclists from 3D models. The system serves itself by generating its own training data without requiring manual annotation, dramatically reducing time consumption while maintaining data quality through controlled synthetic generation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of manually creating training data by annotating real images, the system copies and generates training data synthetically from 3D bicyclist models. This copying approach produces perfectly annotated data automatically, eliminating the time-consuming manual annotation process.

Inventive Principle:
Principle #26Copying

3Measurement precision

If extensive training data is collected to improve detection accuracy, then detection precision is improved, but data collection complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoiddata collection complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system generates training data by copying and rendering 3D bicyclist models rather than collecting real-world images. This synthetic copying approach produces unlimited training data with perfect annotations automatically, eliminating the complexity of real data collection while maintaining high detection accuracy.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system replaces the mechanical process of manually collecting and annotating real images with an automated computational rendering system. This substitution transforms a complex manual process into an automated digital generation process, reducing complexity while increasing data availability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9213892B2Real-time bicyclist detection with synthetic training data
Publication Date: 2015.12.15 HONDA MOTOR CO LTD
  • US9213892B2 patent drawing
  • US9213892B2 patent drawing
  • US9213892B2 patent drawing

AI summary

A determination is made in real-time regarding whether a bicyclist is present in a target image. A target image is received. The target image is classified and an error value for the target image is determined using a linear classifier. If the error value does not exceed the threshold value, the classification is outputted. Otherwise, if the error value exceeds the threshold value, the target image is classified using a non-linear classifier.