Histogram Equalization MCQ
PDF/CDF mapping, global equalization side effects, adaptive CLAHE tiles, and when histogram methods help.
Histogram
Counts
CDF
Mapping
Equalize
Global
CLAHE
Local tiles
Histogram-based enhancement
Histogram equalization spreads intensity usage to improve contrast by remapping via the cumulative distribution—global methods can over-amplify noise in flat regions.
CLAHE
Contrast Limited Adaptive HE applies equalization in tiles and clips histogram peaks to reduce noise amplification and blocking.
Building blocks
CDF
Running sum of normalized histogram defines a monotonic gray-level transform.
Linear stretch
Maps min–max to full range—simple baseline before heavier transforms.
Artifacts
Equalization can wash out natural appearance; clip limit and tile grid matter.
Color images
Apply on luminance channel to avoid hue shifts, or use careful per-channel strategies.
Transform view
Input intensity → T(r) → Output intensity