Figure 2: Image sharpening by GHPF and 2nd order BHPF with D0=50, 100, 150, 200: (a) Original MRI image, (b) 2nd order BHPF, D0=50, (c) GHPF, D0=50, (d) 2nd order BHPF, D0=100, (e) GHPF, D0=100, (f) 2nd order BHPF, D0=150, (h) GHPF, D0=150, (i) 2nd order BHPF, D0=200, (j) GHPF, D0=200.