Spectropolarimetric Thermal Imaging for Texture-Rich Object Ranging

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Solution Overview

Problem

Existing object detection and ranging technologies for autonomous vehicles face challenges in harsh environments and long distances due to the lack of texture in thermal images, leading to diminished features and errors in stereovision, which affect accuracy and 3D vision capabilities.

Innovation Solution

A method for generating object surface texture in thermal infrared images using spectropolarimetric imaging, involving a spectropolarimetric imaging system that captures heat radiation and applies bandpass filters to generate spectral frames, extracts spectral information, and matches it to reference spectral information using statistical methods to enhance texture and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If thermal infrared imaging is used for passive detection and ranging, then energy efficiency and passive operation are improved, but texture information and object feature discernibility deteriorate

Engineering Contradiction:
Improveenergy efficiencyVSAvoidtexture information
Core Design Contradiction:
Use of energy by moving objectVSLoss of information

Solution Approach 1:

The patent transitions from conventional single-channel thermal imaging to spectropolarimetric imaging by adding spectral and polarization dimensions. This multi-dimensional approach captures heat radiation across multiple wavelengths and polarization states, enabling extraction of both thermal and textural information simultaneously, thus resolving the contradiction between passive thermal detection and texture preservation

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

Solution Approach 2:

The patent segments the thermal radiation signal into multiple spectral bands using bandpass filters. By dividing the continuous spectrum into discrete wavelength ranges, the system can process different spectral components separately to extract both temperature information and surface texture characteristics, maintaining texture fidelity while preserving passive thermal detection capabilities

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If LIDAR is used for active detection and ranging, then 3D mapping and distance measurement are improved, but effectiveness at long distances and in harsh environments deteriorates

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoideffectiveness in harsh environments
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the active mechanical laser scanning system with a passive spectropolarimetric imaging system. Instead of emitting light and measuring return times, the system detects emitted thermal radiation across spectral bands, eliminating the line-of-sight limitations and atmospheric interference that plague LIDAR in harsh environments, while maintaining precision through spectral analysis

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

Solution Approach 2:

The patent changes the detection parameter from single-wavelength intensity (LIDAR) to multi-wavelength spectral distribution. By analyzing the spectral shape and polarization characteristics across multiple bands, the system achieves robust object identification and ranging that is insensitive to ambient lighting conditions and atmospheric variations, improving reliability in harsh environments

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If RGB stereovision is used for scene analysis, then cost-effectiveness is improved, but ranging error accumulation and texture deficiency in thermal images deteriorate

Engineering Contradiction:
Improvecost-effectivenessVSAvoidranging accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent creates a composite imaging approach by fusing spectropolarimetric thermal data with spatial information. The system combines spectral fingerprint analysis from multiple wavelength bands with polarization state data to generate enhanced thermal images that preserve texture information, achieving both cost-effectiveness and high ranging accuracy through integrated multi-parameter analysis

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances object detection and ranging capabilities by providing unique spectral fingerprints for tactical semantic segmentation, distinguishing target information from environmental signals, and improving passive ranging accuracy and 3D vision.

Implementation Method 1

receiving heat radiation from a scene by a spectropolarimetric imaging system

Methodology Applied
Scientific EffectHeat radiation: Thermal Radiation

Implementation Method 2

applying a plurality of associated bandpass filters to the spectropolarimetric imaging system and passing the heat radiation therethrough

Methodology Applied
Scientific EffectBandpass filtering: Filter (optical)

Implementation Method 3

extracting spectral information associated with the scene, including pixel-specific temperature representing an object's temperature, and thermal texture factor representing the object's texture

Methodology Applied
Scientific EffectSpectral extraction: Absorption Spectroscopy

Implementation Method 4

matching the extracted spectral information for each pixel from the generated plurality of spectral frames to the generated reference spectral information using a statistical method to minimize the associated variation

Methodology Applied
Scientific EffectStatistical matching:

Data Source

PatentEP4070054B1Heat assisted detection and ranging based on spectropolarimetric imaging
Publication Date: 2025.08.13 PURDUE RES FOUND
  • EP4070054B1 patent drawingFigure 1
  • EP4070054B1 patent drawingFigure 2
  • EP4070054B1 patent drawingFigure 3

AI summary

A method of generating object surface texture in thermal infrared images is disclosed which includes receiving heat radiation from a scene by a spectropolarimetric imaging system, generating a plurality of spectral frames associated with the scene, each frame having a plurality of pixels, for each pixel from the generated plurality of spectral frames, extracting spectral information associated with the scene, including pixel-specific temperature representing an object's temperature, and thermal texture factor representing the object's texture, for each of a plurality of materials having a specific emissivity in a library, generating reference spectral information as a function of temperature and thermal texture, matching the extracted spectral information for each pixel from the generated plurality of spectral frames to the generated reference spectral information using a statistical method to minimize the associated variation, and extracting spectral metadata from the matched reference spectral information for the associated material based on the match.