Fig. 8From: Acquisition of a single grid-based phase-contrast X-ray image using instantaneous frequency and noise filteringFifteen filtered images of the areas indicated by the blue boxes in Fig. 4b, c using three bitonic filters with different parameter values (Step 2: Fig. 4 RT2 to RT4). Top row: simple bitonic filter; middle row: structurally varying bitonic filter; and bottom row: multi-resolution structurally varying bitonic filter. RT, rectangle; Para, parameterBack to article page