Systems and methods for non-intrusive material quality inspection using three- dimensional monostatic radar based imaging

Patent metadata

Field	Value
Publication number	US-12235225-B2
Application number	US-202318185476-A
Country	US
Kind code	B2
Filing date	Mar 17, 2023
Priority date	May 6, 2022
Publication date	Feb 25, 2025
Grant date	Feb 25, 2025

Abstract

This disclosure relates generally to material quality inspection. Conventional approaches available for material quality inspection are unable to address concerns of complexity and cost involved. The technical problem of occluded object detection and material quality inspection for intrinsic defects identification is addressed in the present disclosure. The present disclosure provides a system and method for non-intrusive material quality inspection using three-dimensional monostatic radar based imaging, where the object under inspection undergoes a circular translation motion on a rotating platform. A modified delay-and-sum (m-DAS) algorithm is built by incorporating virtual antenna array to obtain a 3D image reconstruction of the object. From 3D reconstructed images, radial displacement as well as the angular locations of the object is identified which are further used for quality inspection of the material comprised in the object.

First claim

What is claimed is:

1. A system comprising:
a mechanical rotating platform;
an object under inspection positioned on the mechanical rotating platform;
a single static radar positioned at a positioned at a predefined inclination from the object under inspection and the mechanical rotating platform; and
a controller unit in communication with the single static radar, wherein the controller unit comprises:
one or more data storage devices configured to store instructions;
one or more communication interfaces; and
one or more hardware processors operatively coupled to the one or more data storage devices via the one or more communication interfaces, wherein the one or more hardware processors are configured by the instructions to:
(i) acquire, a first set of radar return data from a first reflected signal and a second set of radar return data from a second reflected signal, the first reflected signal being a signal reflected off a first sample setup and the second reflected signal being a signal reflected off a second sample setup in response to a transmitted signal from the single static radar positioned at a predefined inclination from the first sample setup and the second sample setup, wherein the first sample set up comprises the mechanical rotating platform and the second sample set up comprises the object under inspection positioned on the mechanical rotating platform with an offset to center thereof and undergoing a circular translation motion during each rotation of the mechanical rotating platform, and wherein a sample material is placed inside the object under inspection and wherein the radar return data is in form a range time matrix;
(ii) perform, a non-coherent subtraction between the first set of radar return data and the second set of radar return data to obtain a resultant radar return data, wherein resultant radar return data is indicative of a background subtracted range time matrix;
(iii) perform, a plurality of preprocessing steps on the resultant radar return data to obtain a processed range time matrix;
(iv) apply, a range-doppler processing technique on the processed range time matrix to obtain a range-gated matrix indicative of a range time matrix constrained to an observation window;
(v) create a transverse plane image of the object under inspection at a predefined height of the single static radar by applying a modified Delay-and-Sum algorithm on the range-gated range-time matrix, wherein the modified Delay-and-Sum algorithm determines a plurality of virtual antenna positions of the single static radar around the object under inspection and a distance of each pixel of the transverse plane image from each of the plurality of virtual antenna positions of the single static radar;
(vi) iteratively perform steps (i) through (v) to obtain a plurality of transverse plane images of the object under inspection at a plurality of virtual heights of the single static radar, wherein the plurality of virtual heights of the single static radar is indicative of a plurality of transverse cross sections of object under inspection at a plurality of heights; and
(vii) obtain, a three-dimensional reconstructed image of the object under inspection by combining the plurality of transverse plane images.

2. The system of claim 1 , wherein the one or more hardware processors are further configured to
obtain, a 3D reflection intensity map of the object under inspection by using (i) a boundary detection technique and (ii) a thresholding technique;
create, a 3D heatmap view model using the 3D reflection intensity map of the object under inspection for visualization of the sample material placed inside the object under inspection; and
identify, at least one of (i) a high intensity location and (ii) a location with change detection in the 3D heatmap view model to identify one or more anomalies in the sample material placed inside the object under inspection.

3. The system of claim 1 , wherein the one or more hardware processors are further configured to use the resultant set of radar return data to determine an initial three-dimensional reconstructed image of the object under inspection.

4. The system of claim 1 , wherein the plurality of preprocessing steps comprise performing motion filtering, mean subtraction, and envelope detection on the resultant radar return data.

5. The system of claim 1 , wherein the plurality of virtual antenna positions of the single static radar is indicative of virtual motion of the single static radar around the object under investigation in a virtual circular trajectory.

6. A processor implemented method, comprising:
acquiring, via one or more hardware processors, a first set of radar return data from a first reflected signal and a second set of radar return data from a second reflected signal, the first reflected signal being a signal reflected off a first sample setup and the second reflected signal being a signal reflected off a second sample setup in response to a transmitted signal from a single static radar positioned at a predefined inclination from the first sample setup and the second sample setup, wherein the first sample set up comprises a mechanical rotating platform and the second sample set up comprises an object under inspection positioned on the mechanical rotating platform with an offset to center thereof and undergoing a circular translation motion during each rotation of the mechanical rotating platform, and wherein a sample material is placed inside the object under inspection and wherein the radar return data is in form a range time matrix;
performing, via the one or more hardware processors, a non-coherent subtraction between the first set of radar return data and the second set of radar return data to obtain a resultant radar return data, wherein resultant radar return data is indicative of a background subtracted range time matrix;
performing, via the one or more hardware processors, a plurality of preprocessing steps on the resultant radar return data to obtain a processed range time matrix;
applying, via the one or more hardware processors, a range-doppler processing technique on the processed range time matrix to obtain a range-gated matrix indicative of a range time matrix constrained to an observation window;
creating, via the one or more hardware processors, a transverse plane image of the object under inspection at a predefined height of the single static radar by applying a modified Delay-and-Sum algorithm on the range-gated range-time matrix, wherein the modified Delay-and-Sum algorithm determines a plurality of virtual antenna positions of the single static radar around the object under inspection and a distance of each pixel of the transverse plane image from each of the plurality of virtual antenna positions of the single static radar;
iteratively performing, via the one or more hardware processors, steps of acquiring the first set of radar return data and the second set of radar return data to creating the transverse plane image of the object under inspection to obtain a plurality of transverse plane images of the object under inspection at a plurality of virtual heights of the single static radar, wherein the plurality of virtual heights of the single static radar is indicative of a plurality of transverse cross sections of object under inspection at a plurality of heights; and
obtaining, via the one or more hardware processors, a three-dimensional reconstructed image of the object under inspection by combining the plurality of transverse plane images.

7. The method of claim 6 , further comprising:
obtaining, a 3D reflection intensity map of the object under inspection by using (i) a boundary detection technique and (ii) a thresholding technique;
creating, a 3D heatmap view model using the 3D refl

Assignees

• Tata Consultancy Services Ltd

Inventors

• Chowdhury Arijit
• Khasnobish Anwesha
• Rani Smriti
• Kumar Achanna Anil
• Chakravarty Soumya
• Pal Arpan
• Chakravarty Tapas

Classifications

• G01S13/532

  using a bank of range gates or a memory matrix · CPC title

• G01S7/412

  based on a comparison between measured values and known or stored values · CPC title

• G01S13/9064 Primary

  Inverse SAR [ISAR] · CPC title

• G01S13/887

  for detection of concealed objects, e.g. contraband or weapons · CPC title

• G01N22/02 Primary

  Investigating the presence of flaws · CPC title