THz Feature Localization via Wavelength-Based Signal Segmentation

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Solution Overview

Problem

Current THz imaging techniques face challenges in feature localization due to ambiguity in pixel size definition caused by broadband pulses, leading to decreased detection and localization of features based on their size and location, especially when features are similar in size to or smaller than the focal spot sizes, and misalignment with the pixel array.

Innovation Solution

A method that utilizes a transform to convert broadband returns into wavelength-based returns, grouping them into distinct focal diameter categories, calculating intra- and inter-return probabilities, and establishing a refined pixel grid for enhanced feature localization by aligning the scanned features with wavelength groups and overlap regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If broadband pulses are used for imaging, then the imaging capability is improved, but the pixel size definition becomes ambiguous leading to decreased feature localization precision

Engineering Contradiction:
Improveimaging capabilityVSAvoidfeature localization precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The broadband pulse signal is segmented into multiple wavelength components, each associated with a specific focal spot size. By processing each wavelength component separately and then combining the results, the patent resolves the ambiguity of pixel size definition while maintaining the benefits of broadband imaging.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent dynamically adjusts the effective pixel size based on the wavelength content of the signal. Different wavelength ranges are assigned to different pixel sizes according to their focal spot characteristics, creating a dynamic rather than static pixel definition that adapts to the imaging requirements.

Inventive Principle:
Principle #15Dynamics

2Area of stationary object

If pixel size is defined to match the largest focal spot size, then the coverage area is improved, but the image resolution decreases

Engineering Contradiction:
Improvecoverage areaVSAvoidimage resolution
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The imaging process is segmented into multiple wavelength-based processing streams, each with its own optimized pixel size. Shorter wavelengths use smaller pixels for high resolution, while longer wavelengths use larger pixels for broader coverage, and the results are combined to achieve both goals simultaneously.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If pixel size is defined to match the smallest focal spot size, then the image resolution is improved, but the measured area coverage decreases

Engineering Contradiction:
Improveimage resolutionVSAvoidmeasured area coverage
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

Multiple wavelength components with different focal spot sizes are merged into a single composite image. Each wavelength contributes to different spatial frequencies, and their combination provides both high resolution (from short wavelengths) and broad coverage (from long wavelengths) in the final image.

Inventive Principle:
Principle #5Merging (Combining)

4Difficulty of detecting and measuring

If features are similar in size to or smaller than focal spot sizes, then the detection capability is challenged, but the localization accuracy decreases

Engineering Contradiction:
Improvedetection capabilityVSAvoidlocalization accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent introduces a wavelength dimension to the imaging process, transforming the problem from a single spatial dimension to a combined wavelength-spatial domain. By analyzing features across multiple wavelength components, small features can be detected and localized with higher accuracy than would be possible with a single focal spot size.

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

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

This approach dynamically defines pixel size and location, improving image resolution and feature localization by separating the signal from each pulse into component spot sizes, allowing for precise spatial analysis and accurate representation of feature positions.

Implementation Method 1

When light passes through an aperture, or lens, diffraction occurs. Equation (1) describes the intensity of light in the focal plane... The pattern resulting from this diffraction is referred to as the Airy pattern.

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

The position of the pulses defines the location of each pixel... The size of each pixel is defined by the focal spot size of the pulse... Equation (3), which describes this diameter [focal spot diameter]

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentUS11163060B1Feature localization through broadband processing
Publication Date: 2021.11.02 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES
  • US11163060B1 patent drawing
  • US11163060B1 patent drawing
  • US11163060B1 patent drawing

AI summary

A method for increasing localization utilizing overlapped broadband pulses includes using a transform to convert broadband returns into wavelength based returns. The wavelength based returns are grouped into at least two wavelength group returns for each location having different focal diameters. Intra-return probabilities of object location are computed from the group returns. Inter-return probabilities are computed for overlapping regions of the pulse returns. A pixel grid is established for displaying the calculated object location probabilities. By further processing, the pixel grid can be refined to show finer details.