Spatial Filtering of Image Noise Based on the Spot Apparatus

The paper discusses two approaches for spatial filtering of noise in CT images. The first method modifies a noise reduction algorithm for binary images by representing a grayscale image as a stack of contrast layers and processing each layer independently. Its key drawback is high computational complexity. The second, more efficient approach also uses a three-dimensional representation but scans not the entire volume, only the region near its “upper boundary”, which significantly speeds up processing.