Real-Time Local Noise Filter in 3-D Visualization of CT Data

Removing noise in computer tomography (CT) data for real-time 3-D visualization is vital to improve the quality of the final display. However, the CT noise cannot be removed by straight averaging because the noise has a broadband spatial frequency that is overlapping with the interesting signal frequencies. To improve the display of structures and features contained in the data, we present spatially variant filtering that performs averaging of subregions around a central region. We compare our filter with five other similar spatially variant filters regarding entropy and processing time. The results demonstrate significant improvement of the visual quality with processing time still within the millisecond range.