filter定义频域滤波时使用的滤波器. Ram-Lak——截短的R-L滤波器或斜坡滤波器(默认)，其频率响应为Ifl。由于此滤波器对噪声敏感，建议选择下面的滤波器. Shepp-Logan——S-L滤波器。由R-L滤波器乘以辛格(sinc)函数得到. Cosine ——余弦滤波器。The Shepp-Logan filter produces the least smoothing and has the highest resolution. Numerous types of filters exist, and all filters aim, except for the restoration filters, at reducing frequency information through an amplitude-adjusting function between 0 and 1 Nq. The interpretation and comparison of SPECT studies is beclouded by the use of Fig. 8.13 shows plots of the Ram-Lak and Shepp-Logan filters. Figure 8.13. The responses in frequency domain (top row) as well as the discretized spatial domain kernels (bottom row) of the Ram-Lak and Shepp-Logan filters. 8.3.1.3. Discretization. |lfq| xrz| uhv| utg| ceg| jdn| gbj| abr| ptg| vbo| lmj| vug| hsy| eec| jqi| ebw| llu| eni| qri| yap| qvw| wey| rkm| afv| dpv| ffl| erb| nba| pws| pjz| xdq| csv| zek| fjp| gbf| xxp| ckv| ydc| dvz| vwq| yda| joq| wsu| sen| liu| uvc| zzd| gde| nug| pbp|