Bilateral filter

For other uses, see Bilateral (disambiguation).

A bilateral filter is an edge-preserving and noise reducing smoothing filter. The intensity value at each pixel in an image is replaced by a weighted average of intensity values from nearby pixels. This weight is based on a Gaussian distribution. Crucially the weights depend not only on Euclidean distance but also on the radiometric differences (differences in the range, e.g. color intensity). This preserves sharp edges by systematically looping through each pixel and according weights to the adjacent pixels accordingly.

Adobe Photoshop implements a bilateral filter in its surface blur tool.

See also

• Gaussian filter
• Gaussian function
• Gaussian blur
• Convolution

External links

• Kunal N. Chaudhury Constant-time filtering
• Kunal N. Chaudhury, Daniel Sage, and Michael Unser Java plugin, Fast bilateral filtering
• Sylvain Paris, Pierre Kornprobst, Jack Tumblin, Frédo Durand, Bilateral Filtering: Theory and Applications, preprint
• Sylvain Paris, Pierre Kornprobst, Jack Tumblin, Frédo Durand, A Gentle Introduction to Bilateral Filtering and its Applications, SIGGRAPH 2008 class
• Ben Weiss, Fast Median and Bilateral Filtering, SIGGRAPH 2006 preprint
• Carlo Tomasi, Roberto Manduchi, Bilateral Filtering for Gray and Color Images (shorter HTML version), proceedings of the ICCV 1998