Phase aberration caused by the skull is a major barrier to achieving high quality photoacoustic images of human and non-human primates’ brains. To address this issue, time-reversal methods have been used but they are computationally demanding and slow due to relying on solving the full-wave equation. The proposed approach is based on model-based image reconstruction in the frequency-domain to achieve near real-time image reconstruction. The relationship between an imaging region and transducer array elements can be mathematically described as a model matrix and the image reconstruction can be performed by pseudo-inverse of the model matrix. The model matrix is numerically calculated due to the lack of analytical solutions for transcranial ultrasound. However, this calculation only needs to be performed once for a given experimental setup and the same acoustic medium, and is an offline process not affecting the actual image reconstruction time. This non-iterative mode-based method demonstrates a substantial improvement in image reconstruction time, being approximately 18 times faster than the time-reversal method, all while maintaining comparable image quality.

中文翻译：

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基于频域模型的经颅光声成像重建方法：二维数值研究

由头骨引起的相位像差是获得人类和非人类灵长类动物大脑的高质量光声图像的主要障碍。为了解决这个问题，已经使用了时间反演方法，但由于依赖于求解全波方程，这些方法计算量大且速度慢。所提出的方法基于频域中基于模型的图像重建，以实现近实时图像重建。成像区域和换能器阵列元件之间的关系可以在数学上描述为模型矩阵，并且可以通过模型矩阵的伪逆来执行图像重建。由于经颅超声缺乏解析解，模型矩阵采用数值计算。然而，对于给定的实验设置和相同的声学介质，这种计算只需要执行一次，并且是一个离线过程，不会影响实际的图像重建时间。这种基于非迭代模式的方法展示了图像重建时间的显着改进，比时间反转方法快了约 18 倍，同时保持了可比较的图像质量。