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Figure 3. Resolution metric. Composite image shows the spatial-resolution scale applied to a representative portion of a radiograph. Reduction in resolution progresses from grade 1 (top left and bottom right: unaltered original, 100%) to grade 15 (bottom row, second from right: 4%). The percentages are a measure of two-dimensional spatial resolution, which was determined on the basis of the square of the bandwidth reduction implemented with power-law filters and can be thought of as the percentage of pixels displayed.