3 x 3 Median Filter 3 iterations of Anisotropic Diffusion, conductance = .1 Canny Edge Detection, threshold = 10 Hough Transform, threshold = 30% of maximum value	Marr-Hildreth Edge Detection, threshold = 20, sigma = 2 Hough Transform, threshold = 35% of maximum value
3 x 3 Median Filter Canny Edge Detection, threshold = 6 Hough Transform, threshold = 35% of maximum value	Marr-Hiltdreth Edge Detection, threshold = 3.5, sigma = 2 Hough Transform, threshold = 39% of maximum value
3 x 3 Median Filter 3 iterations of Anisotropic Diffusion, conductance = .1 Canny Edge Detection, threshold = 5 Hough Transform, threshold = 72% of maximum value	Marr-Hildreth Edge Detection, threshold = 2, sigma = 2 Hough Transform, threshold = 75% of maximum value