A micro-electromechanical system (MEMS) scanning mirror accelerates the raster scanning of optical-resolution photoacoustic microscopy (OR-PAM). However, the nonlinear tilt angular-voltage characteristic of a MEMS mirror introduces distortion into the maximum back-projection image. Moreover, the size of the airy disk, ultrasonic sensor properties, and thermal effects decrease the resolution. Thus, in this study, we proposed a spatial weight matrix (SWM) with a dimensionality reduction for image reconstruction. The three-layer SWM contains the invariable information of the system, which includes a spatial dependent distortion correction and 3D deconvolution. We employed an ordinal-valued Markov random field and the Harris Stephen algorithm, as well as a modified delay-and-sum method during a time reversal. The results from the experiments and a quantitative analysis demonstrate that images can be effectively reconstructed using an SWM; this is also true for severely distorted images. The index of the mutual information between the reference images and registered images was 70.33 times higher than the initial index, on average. Moreover, the peak signal-to-noise ratio was increased by 17.08% after 3D deconvolution. This accomplishment offers a practical approach to image reconstruction and a promising method to achieve a real-time distortion correction for MEMS-based OR-PAM.

中文翻译：

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基于微机电系统的光声显微镜降维重建中的空间权重矩阵

微机电系统（MEMS）扫描镜可加快光学分辨率光声显微镜（OR-PAM）的光栅扫描。然而，MEMS镜的非线性倾斜角电压特性将畸变引入到最大的反投影图像中。此外，通风盘的尺寸，超声波传感器的特性和热效应会降低分辨率。因此，在这项研究中，我们提出了一种降维的空间权重矩阵（SWM），用于图像重建。三层SWM包含系统的不变信息，其中包括空间相关的失真校正和3D反卷积。在时间反转过程中，我们采用了序数值马尔可夫随机场和哈里斯斯蒂芬算法，以及改进的延迟和求和方法。实验和定量分析的结果表明，使用SWM可以有效地重建图像。对于严重失真的图像也是如此。平均而言，参考图像和配准图像之间的相互信息索引比初始索引高70.33倍。此外，在3D反卷积后，峰值信噪比提高了17.08％。这一成就为图像重建提供了一种实用的方法，并为基于MEMS的OR-PAM实现了实时失真校正提供了一种有前途的方法。一般。此外，在3D反卷积后，峰值信噪比提高了17.08％。这一成就为图像重建提供了一种实用的方法，并为基于MEMS的OR-PAM实现了实时失真校正提供了一种有前途的方法。一般。此外，在3D反卷积后，峰值信噪比提高了17.08％。这一成就为图像重建提供了一种实用的方法，并为基于MEMS的OR-PAM实现了实时失真校正提供了一种有前途的方法。