This work presents two variants of Born-series methods, for the first time, providing a numerical solution to the time-independent photoacoustic wave equation. These methods are effective in providing accurate solution even when there is a mismatch in speed-of-sound between the source and the ambient region. The traditional Born-series (TBS) and convergent Born-series (CBS) methods have been systematically compared for a test imaging case. The solution was computed keeping speed-of-sound outside the source as constant (1500 m/s) and varying the same quantity from 1950 to 1200 m/s inside the source (a disc with 5 μm radius) over a large frequency band (7–2000 MHz). The TBS method fails to converge when the variation in the speed-of-sound is approximately % or %. The CBS method provides the required robust numerical solution even in case of mismatch in speed-of-sound in various regions of imaging domain.

中文翻译：

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收敛Born级数提高非时变光声波动方程数值解的精度

这项工作首次提出了玻恩级数方法的两种变体，为与时间无关的光声波动方程提供了数值解。即使在声源和环境区域之间的声速不匹配时，这些方法也能有效地提供准确的解决方案。传统的玻恩级数 (TBS) 和收敛玻恩级数 (CBS) 方法已针对测试成像案例进行了系统比较。计算的解决方案是保持源外的声速恒定 (1500 m/s)，并在大频带上从 1950 到 1200 m/s 的源（半径为 5 μm 的圆盘）内改变相同的数量（ 7–2000 兆赫）。当声速变化约为 % 或 % 时，TBS 方法无法收敛。