CLAHEa

CLAHEa is a technique used in image processing to enhance the contrast of an image. It stands for Contrast Limited Adaptive Histogram Equalization. Unlike standard histogram equalization, which applies the same transformation to the entire image, CLAHE divides the image into smaller, uniform regions called tiles. It then computes the histogram equalization for each tile independently.

The "contrast limiting" aspect of CLAHE is crucial. Without it, histogram equalization in localized regions can amplify noise in areas with low contrast. CLAHE addresses this by clipping the histogram at a predefined threshold, preventing excessive amplification of intensity differences. Any pixel counts above this threshold are redistributed to other bins in the histogram. This limits the contrast enhancement in each tile, thereby reducing noise amplification.

The output of CLAHE is a more detailed and visually appealing image, especially in regions that were previously too dark or too bright. It is particularly effective for medical imaging, satellite imagery, and other applications where subtle details are important. The parameters for CLAHE, such as the number of tiles and the contrast limit, can be adjusted to fine-tune the enhancement for specific image types.