Pedestrian Detection via Kernel Discriminant Analysis

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Solution Overview

Problem

Existing vehicle periphery observation systems face challenges in accurately detecting pedestrians due to environmental fluctuations such as day-night changes and seasonal variations, leading to reduced efficiency and potential failure in pedestrian detection.

Innovation Solution

The implementation of an image processing equipment that performs kernel discriminant analysis on photographed images, using an input feature vector generation unit, discriminant analysis operations unit, score accumulation unit, and score judgment unit to determine if an object is a pedestrian, with features such as size, upper portion shape, and side portion shape being normalized and analyzed in a discriminant space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If infrared radiation camera is used for pedestrian detection, then detection capability in certain conditions is improved, but detection accuracy deteriorates under environmental fluctuations such as day-night changes and seasonal variations

Engineering Contradiction:
Improvepedestrian detection capabilityVSAvoidpedestrian detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameter from thermal radiation (infrared) to optical reflection (visible light). By using visible light cameras instead of infrared cameras, the system detects pedestrians based on reflected light rather than thermal emission, making detection results independent of temperature differences between the human body and ambient atmosphere. This parameter change resolves the contradiction by maintaining detection accuracy across varying environmental conditions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complex image processing is performed to improve pedestrian identification accuracy, then detection accuracy is improved, but processing time increases

Engineering Contradiction:
Improvepedestrian identification accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the image processing task into distinct stages: first extracting candidate regions using simple features (size, position), then performing detailed analysis only on these candidates using kernel discriminant analysis. This segmentation allows the system to maintain high accuracy through sophisticated analysis while reducing overall processing time by limiting complex operations to a small subset of potential pedestrian regions rather than analyzing the entire image.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary filtering by extracting and analyzing basic features (object size, position, simple shape characteristics) before applying the more computationally intensive kernel discriminant analysis. This preliminary action identifies candidate pedestrian regions that are then subjected to detailed analysis, ensuring high accuracy while minimizing processing time by avoiding exhaustive analysis of all image regions.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If comprehensive feature analysis is performed on all detected objects, then identification accuracy is improved, but operational load increases

Engineering Contradiction:
Improveobject identification accuracyVSAvoidoperational load
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies comprehensive feature analysis (kernel discriminant analysis with multiple features including size, upper portion shape, and side portion shape) only to candidate objects that have already been identified through preliminary filtering. By performing partial analysis on the entire image set followed by excessive (comprehensive) analysis only on selected candidates, the system achieves high identification accuracy while keeping operational load manageable through selective application of complex processing.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP1760632B1Image processing equipment
Publication Date: 2021.06.16 SUBARU CORP
  • EP1760632B1 patent drawingFigure 1
  • EP1760632B1 patent drawingFigure 2
  • EP1760632B1 patent drawingFigure 3

AI summary

A design for the high speed identification of a pedestrian at an image is provided, having an input feature vector generation unit 23b for generating, based on an image of an object, an input feature vector u that includes as elements the object's size, the object's upper portion shape, and the object's side portion shape; a kernel discriminant analysis operations unit 23c for generating a vector y mapped to the discriminant space, through performing operations for kernel discriminant analysis based on the input feature vector; and an object determination unit 23d for determining whether the object is a pedestrian or not, depending on whether or not this vector y is within a fixed area at the discriminant space.