# Demonstration of 3D ISAR Security Imaging at 24GHz with a Sparse MIMO Array

## TL;DR

This paper demonstrates a 3D ISAR security imaging system at 24GHz using a sparse MIMO array, combining advanced calibration, motion tracking, and GPU-based processing for real-time human and object imaging.

## Contribution

It introduces a novel 3D ISAR imaging setup with a sparse MIMO array, calibration procedures, and an integrated motion tracking and neural network recognition system.

## Key findings

- Successful 3D imaging of humans with concealed objects
- Effective calibration of MIMO channel imbalance
- Real-time imaging achieved with GPU acceleration

## Abstract

A 3D ISAR security imaging experiment at 24GHz is demonstrated with a sparse MIMO array. The MIMO array is an 8Tx/16Rx linear array to achieve real-aperture imaging along the vertical dimension. It is time-switching multiplexed with a low-cost FMCW transceiver working at 22GHz-26GHz. A calibration procedure is proposed to calibrate the channel imbalance across the MIMO array. The experiment is conducted on human moving on a cart, where we take advantage of the linear motion of human to form inverse synthetic aperture along the horizontal dimension. To track the motion of human, a 3D depth camera is used as an auxiliary sensor to capture the rough position of target to aid ISAR imaging. The back projection imaging algorithm is implemented on GPU for quasi-real-time operation. Finally, experiments are conducted with real human with concealed objects and a preliminary automatic object recognition algorithm based on convolutional neural networks are developed and evaluated on real data.

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Source: https://tomesphere.com/paper/1908.06619