Spatio-Spectral Feature Learning for Shadow-Object Distinction

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Solution Overview

Problem

Current computer systems face challenges in accurately distinguishing between shadows and material objects in images, which is crucial for applications like computer vision and robotics, as they lack the cognitive ability to automatically differentiate between the two based on pixel values alone.

Innovation Solution

A computerized method using spatio-spectral features, specifically the X-junctions where material edges and illumination boundaries intersect, is employed to identify material edges by calculating spectral ratios and applying machine learning techniques to classify these features, allowing for the differentiation between shadows and objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional pixel value analysis is used, then the processing is simple, but the ability to distinguish shadows from material objects is poor

Engineering Contradiction:
Improvedistinguishing accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from analyzing only spatial pixel values to incorporating spectral dimensions by capturing images across multiple wavelengths. This dimensional expansion allows the system to distinguish shadows from material objects by analyzing how different materials reflect light at various spectral wavelengths, thereby improving measurement precision without excessive complexity increase.

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

Solution Approach 2:

The patent changes the parameters being analyzed from simple intensity values to spectral ratios and spatio-spectral features. By computing ratios of pixel values across different wavelengths and analyzing these spectral characteristics, the system achieves better shadow-material distinction while managing complexity through focused feature extraction.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If spectral analysis is performed to improve shadow detection, then the accuracy improves, but the computational complexity increases

Engineering Contradiction:
Improveshadow detection accuracyVSAvoidcomputational power
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent extracts specific spectral features (ratios of pixel values at different wavelengths) from the full spectral data. By focusing computation on these key extracted features rather than processing all spectral information, the system achieves improved shadow detection accuracy while reducing the overall computational power required.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary spectral ratio calculations and feature extraction before the main shadow detection algorithm. By pre-computing spectral characteristics and organizing them into meaningful features, the system reduces the computational burden of the subsequent shadow-material distinction process.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If multiple wavelength images are captured, then the spectral information improves, but the data processing time increases

Engineering Contradiction:
Improvespectral information completenessVSAvoidprocessing time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent extracts essential spectral information by computing ratios between wavelengths rather than processing all spectral data in full detail. This extraction approach preserves the critical spectral information needed for shadow detection while significantly reducing the processing time compared to analyzing complete spectral datasets.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the raw spectral data from multiple wavelengths into spectral ratio parameters. This parameter transformation condenses the information from multiple wavelength images into compact spectral features that retain the essential spectral information while enabling faster processing.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2074557B1Method and system for learning spatio-spectral features in an image
Publication Date: 2014.11.12 TANDENT VISION SCIENCE INC
  • EP2074557B1 patent drawingFigure 1
  • EP2074557B1 patent drawingFigure 2~3
  • EP2074557B1 patent drawingFigure 4

AI summary

In a first exemplary embodiment of the present invention, an automated, computerized method is provided for determining illumination flux in an image. According to a feature of the present invention, the method comprises the steps of performing a computer learning technique to determine spatio-spectral information for the images, and utilizing the spatio-spectral information to identify illumination flux.