Hakakzadeh Soheil, Amjadian Mohammadreza, Zhang Yachao, Mostafavi Seyed Masood, Kavehvash Zahra, Wang Lidai
Electrical Engineering Department of Sharif University of Technology, Tehran, Iran.
Equal Contribution.
Biomed Opt Express. 2023 Jan 5;14(2):651-666. doi: 10.1364/BOE.480842. eCollection 2023 Feb 1.
In a photoacoustic (PA) imaging system, the detectors are bandwidth-limited. Therefore, they capture PA signals with some unwanted ripples. This limitation degrades the resolution/contrast and induces sidelobes and artifacts in the reconstructed images along the axial direction. To compensate for the limited bandwidth effect, we present a PA signal restoration algorithm, where a mask is designed to extract the signals at the absorber positions and remove the unwanted ripples. This restoration improves the axial resolution and contrast in the reconstructed image. The restored PA signals can be considered as the input of the conventional reconstruction algorithms (e.g., Delay-and-sum (DAS) and Delay-multiply-and-sum (DMAS)). To compare the performance of the proposed method, DAS and DMAS reconstruction algorithms were performed with both the initial and restored PA signals on numerical and experimental studies (numerical targets, tungsten wires, and human forearm). The results show that, compared with the initial PA signals, the restored PA signals can improve the axial resolution and contrast by 45% and 16.1 dB, respectively, and suppress background artifacts by 80%.
在光声（PA）成像系统中，探测器存在带宽限制。因此，它们采集到的光声信号带有一些不需要的波纹。这种限制会降低分辨率/对比度，并在重建图像的轴向方向上产生旁瓣和伪影。为了补偿有限带宽效应，我们提出了一种光声信号恢复算法，其中设计了一个掩码来提取吸收体位置处的信号并去除不需要的波纹。这种恢复提高了重建图像的轴向分辨率和对比度。恢复后的光声信号可被视为传统重建算法（如延迟求和（DAS）和延迟相乘求和（DMAS））的输入。为了比较所提方法的性能，在数值和实验研究（数值目标、钨丝和人体前臂）中，分别使用初始光声信号和恢复后的光声信号执行了DAS和DMAS重建算法。结果表明，与初始光声信号相比，恢复后的光声信号可分别将轴向分辨率和对比度提高45%和16.1 dB，并将背景伪影抑制80%。
