Apparently Bilateral filter may produce similar results as Noise reduction or Surface blur effects. It's hard to draw direct comparison (I'm not aware of internal implemetation details of standard effects) but I may present my subjective comparison of images produced.
The first important thing is that Bilateral filter has 3 parameters (rather than 2 in case of standard effects):
- Kernel size - this can be treated as radius, it defines how many surrounding pixels take part in calculations for each specific pixel. Greater value is required for High-Res images.
- Color factor - this one can be treated as color tolerance, the greater the values is the larger would be areas blurred and more pixels would be grouped
- Spatial factor - this one defines how strong is blur within areas (domains) of similar colors
Normally a combination of great spatial factor and small color factor is used to achieve noise reduction; large values for both parameters are for fancy blurry effects.
The bellow example shows difference in noise reduction. I’ve tried to achieve similar looking results for both Bilateral and Noise reduction effects by playing with parameters.
Original:
Bilateral - left, Noise reduction(10, 0.80) - right:
Noise reduction effect changes luminosity (shaded passenger side of the car), Bilateral filter preserves more details (trees in the background) and in my opinion noise is higher on the second image (far lanterns, bonnet).
If we try to achieve blurry effect the difference is more distinctive.
Original:
Bilateral(15, 60, 100):
Surface blur(20, 50):
As you can see there're differences in the resulting images and the filter can be treated as an alternative to both standar Noise reduction and Surface blur effects.
