Millimeter Wave Detection of Covered Dielectric Objects
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Solution Overview
Problem
Existing methods for detecting concealed non-metallic objects using millimeter waves struggle with spatially unambiguous detection due to higher scattering complexity from non-flat surfaces, leading to inaccurate identification of objects with tapered surfaces.
Innovation Solution
The method involves observing the interference of millimeter waves reflected from the front and rear sides of concealed objects, comparing the difference in signal amplitudes to a threshold, and using three-dimensional focusing to determine the object's location, allowing for unambiguous detection of dielectric objects regardless of shape or surface complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If millimeter waves are used to detect concealed non-metallic objects, then detection capability for non-metallic materials is improved, but spatial resolution and unambiguous detection are degraded due to scattering complexity from non-flat surfaces
Solution Approach 1:
The patent transitions from two-dimensional surface scanning to three-dimensional volumetric imaging by introducing the depth dimension through time-resolved detection of wave reflections from different depths within and beneath the surface, enabling unambiguous spatial localization of concealed objects regardless of surface geometry
Solution Approach 2:
The patent changes the detection parameter from simple amplitude measurement to analysis of the complete wave response including amplitude, phase, and time-of-flight characteristics, allowing differentiation between surface scattering effects and actual concealed objects through multiple physical parameters
2Ease of operation
If conventional reflection measurement is used, then detection process is simple, but accurate identification of objects with tapered surfaces is impossible due to scattering
Solution Approach 1:
The patent introduces an intermediary signal processing layer that separates the complex scattered wave field into component reflections from different interfaces (front surface, rear surface, concealed objects), allowing accurate object identification by analyzing the mediator signals rather than the raw complex reflection pattern
Solution Approach 2:
The patent replaces simple amplitude-based detection with a comprehensive wave field analysis system that measures multiple parameters (amplitude, phase, time-of-flight) and uses computational methods to reconstruct object properties, substituting mechanical simplicity with informational completeness
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 ensures accurate and unambiguous detection of concealed objects, including those with complex shapes, by identifying a specific interference response and filtering noise, providing reliable results even with varying permittivity and mechanical-geometric structures.
Implementation Method 1
the interference—that is, the superposition—of the wave reflected in the transmission direction at the front side of the concealed object and of the wave reflected in the transmission direction at the rear side of the concealed object, is observed
Implementation Method 2
millimeter waves are reflected only slightly or not at all in the air and the clothing of the person under investigation and experience an approximately total reflection on metallic objects and on objects with a high water content
Implementation Method 3
an object made from a non-metallic material, for example, a knife made of ceramic or an explosive powder kept concealed in the proximity of the human body, can be identified by measuring the modulus and the phase of the reflected millimeter waves by means of a focusing method
Data Source
AI summary
The invention relates to a method for detecting a covered dielectric object, where a microwave signal that can be modified in frequency is generated at a particular bandwidth and transmitted in the direction of the covered dielectric object. The microwave signal reflected by the object is then obtained from the three-dimensional measurement result in a lateral, two-dimensional pattern, a highest signal amplitude and a second-highest signal amplitude within a particular time period before or after the received microwave signal is identified in a plurality of pattern points of the pattern. The object is detected if an accumulation of pattern points of the pattern is present, in which the difference in each case between the highest and the second highest signal amplitude of the received microwave signal is less than a defined threshold value.