Generalized synthetic aperture sensing with wavefront coding

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04161
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21030:Measurement engineering-related
• Research Institution: Yamagata University
• Principal Investigator: Tamura Yasutaka 山形大学, 大学院理工学研究科, 名誉教授 (40171904)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 多次元信号処理 / 波面の符号化 / 合成開口 / L1ノルム最小化 / デルタシグマ変調

Outline of Final Research Achievements

The relationship between the data acquisition conditions and the information to be recovered in the synthetic aperture type sensing system is discussed from the viewpoint of "wavefront coding" in a generalized manner, and the guideline for the system design is theoretically and empirically presented.
By using singular value decomposition analysis, we proposed a method of wide null formation to limit the measurement conditions, and confirmed its effectiveness. In addition, by applying the L1 norm minimization method, which has been attracting attention as a compressed sensing method, we proposed and verified a method for recovering target information from incomplete observation data. In addition, we proposed a method to encode two-dimensional wave distributions using the nonlinear characteristics of sensors. These investigations were carried out mainly by numerical simulations and partly by actual measurements.

Free Research Field

計測工学，信号処理

Academic Significance and Societal Importance of the Research Achievements

医療やレーダなど広い応用分野を持つ合成開口技術は，観測データから対象の情報を復元する計測の問題として一般化でき，学術的に重要な意義を持つ。
本研究では，合成開口技術を，時間と空間の両次元に渡る多次元信号である波面を符号化する過程として扱うことでデータ取得と情報復元の最適化設計を図る。また，ランダム配置された素子や多重反射・共鳴・非線形性などの，従来は利用されることの少なかった特性を利用した新しい合成開口システムを可能にすることを目指す。本研究の成果は，高フレームレート・高分解能の超音波撮像システムのや，低コストの車載用レーダなどへの応用が可能であり，広い分野の産業への貢献が期待できる。