Filtered backprojection is an image reconstruction technique for Compton imaging that provides reasonably high resolution at much lower computational costs when compared to iterative methods. This work applies a Wiener filter that has been derived for spherical harmonics on Compton imaging using the OrionUM pixelated CdZnTe imaging spectrometer. To regularize the filter, an investigation is made into the power spectral density of the signal and noise to develop an appropriate spectral signal-to-noise ratio model for the restoration process. Experimental measurements were conducted with two ²²⁸ Th sources placed 30° apart. The resulting filtered image of the two sources has an average full-width-at-half-maximum (FWHM) of 9.8° or 7.5° when using a mean squared error and structural similarity optimization approach, respectively, an improvement from the 29.0° FWHM image when using simple backprojection.

中文翻译：

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康普顿成像中使用像素化CdZnTe球谐维纳滤光片的滤波反投影

滤波反投影是用于Compton成像的图像重建技术，与迭代方法相比，它以较低的计算成本提供了合理的高分辨率。这项工作应用了维纳滤波器，该滤波器是使用OrionUM像素化CdZnTe成像光谱仪在康普顿成像中针对球谐产生的。为了对滤波器进行正则化，需要对信号和噪声的功率谱密度进行研究，以开发出适合于恢复过程的合适的谱信噪比模型。实验测量使用两个²²⁸ 光源相距30°。当使用均方误差和结构相似性优化方法时，两个源的最终滤波图像的半峰平均全宽（FWHM）分别为9.8°或7.5°，与29.0°FWHM相比有所改善使用简单反投影时的图像。