Lanzavecchia S, Tosoni L, Bellon P L
Università degli Studi, Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Milan, Italy.
Comput Appl Biosci. 1995 Aug;11(4):373-8. doi: 10.1093/bioinformatics/11.4.373.
A single projection of a helical distribution of matter allows one to obtain the complete three-dimensional reconstruction of the structure. This task is usually performed by a Fourier-Bessel algorithm, which is more efficient than a customary fast Fourier transform inversion. This article describes how to achieve such a result by a direct Fourier method in a reasonable time. Once the two-dimensional transform of the projection is obtained from the source image, it is possible to build up the three-dimensional transform array, in Cartesian coordinates, that yields the reconstruction by a straightforward Fourier inversion. Images of projected helices should be studied with high sampling rates to enhance the resolution, and the segments of helix should be long enough to give a satisfactory signal-to-noise ratio. These conditions result in three-dimensional transform arrays that would require one or more gigabytes of storage. The strategy proposed here requires much less storage and is fast enough to allow the reconstruction to be performed with different parameters and filters in a very short time without any sacrifice in resolution.
物质螺旋分布的单个投影能让人获得结构的完整三维重建。此任务通常由傅里叶 - 贝塞尔算法执行，该算法比传统的快速傅里叶变换反演更高效。本文描述了如何通过直接傅里叶方法在合理时间内实现这一结果。一旦从源图像获得投影的二维变换，就可以构建笛卡尔坐标下的三维变换数组，通过直接的傅里叶反演得到重建结果。应使用高采样率研究投影螺旋的图像以提高分辨率，并且螺旋段应足够长以给出令人满意的信噪比。这些条件会导致三维变换数组需要一吉字节或更多的存储空间。这里提出的策略所需存储空间少得多，并且速度足够快，能够在非常短的时间内使用不同参数和滤波器进行重建，而不会在分辨率上有任何损失。
