In radiographic post-processing, which method maps input exposure values to a new brightness level using a stored table?

• A. Histogram analysis
• B. Rescaling
• C. Post-processing
• D. Lookup table (LUT) conversion

Answer: (D)

In radiographic post-processing, using a stored table to map input exposure values to a new brightness level is done with a lookup table (LUT) conversion. A LUT is a precomputed array where each possible pixel value serves as an index, and the corresponding entry defines the output display value. This enables fast, per-pixel transformations and allows non-linear adjustments (like windowing or gamma curves) to optimize contrast and brightness for display.

Histogram analysis, while important for informing adjustments, does not perform the per-pixel value mapping itself. Rescaling describes a linear adjustment of values, which can be implemented with a LUT but is not inherently the stored-table mapping by itself. Therefore, the method described is LUT conversion.