Visere => Visere Support => Topic started by: Darian on November 19, 2010, 09:36:04 am

Title: AQuaDenoise Filter Parameters
Post by: Darian on November 19, 2010, 09:36:04 am
Question from user:

Can you explain what each of the values in Aqua noise filter mean:

1. AQua denoise has Sigma and Vector.  Can you explain these?
2. UnSharp Masking - This one I know
3. Xray Denoise - I have been having trouble with this one.  Min/Max and
Average always make the image look like bunch of blocks no matter what value
I use.  So may be you can explain this to me and give me some example values
to use.


Here are some default values.  I will try to put together a document and post it as part of our DMA Algorithms manual.

AQua Denoise: Sigma = 5 and WindowSize = 3
In this case, sigma represents the noise level and WindowSize represents the area used for denoising purposes.  The higher the window size, the slower the denoising algorithm.  For sigma, the higher the value, the more noise is assumed in the image and the more aggressive the denoising algorithm is.  Sigma is the standard deviation of the White Gaussian noise that's assumed in the image.

UnSharpMasking: R = 50 and Gain = 0.8
R is the size of the blurring window.  The gain is how much power we use to boost the high frequency energies (i.e. edges) in the image.  The higher the values, the more blurring.

Denoise XRay: noise level = 0.039, MinMaxR = 1, and AverageR = 5
This filter denoises salt and pepper like images.  If there are black dots in images, they are removed, without causing the edge artifacts that a median filter would cause.

Examples of XRay Denoise and Unsharp Masking are available here: