Bilateral filtering for gray and color images

TLDR

Bilateral filtering smooths images while preserving edges by nonlinearly combining nearby pixel values, and in color images it enforces the perceptual metric of CIE‑Lab to smooth colors in a human‑perception‑tuned manner. The method is noniterative, local, and simple, combining gray levels or colors based on both geometric closeness and photometric similarity, favoring nearby values in domain and range. Bilateral filtering eliminates phantom colors along edges in color images and reduces phantom colors present in the original image.

Abstract

Bilateral filtering smooths images while preserving edges, by means of a nonlinear combination of nearby image values. The method is noniterative, local, and simple. It combines gray levels or colors based on both their geometric closeness and their photometric similarity, and prefers near values to distant values in both domain and range. In contrast with filters that operate on the three bands of a color image separately, a bilateral filter can enforce the perceptual metric underlying the CIE-Lab color space, and smooth colors and preserve edges in a way that is tuned to human perception. Also, in contrast with standard filtering, bilateral filtering produces no phantom colors along edges in color images, and reduces phantom colors where they appear in the original image.