I have studied speckle reduction in ultrasonund images using nonisotropic adaptive filtering. I don't understand how to you calculate the direction angle, which is applied when computing the value of G theta. I think that the angle is computed by curve fitting, which is calculated by the first order derivation and the angle is equal to arctan of the slope. My questions are as follows:
1. Which methods do you use to conduct curve fitting?
2. How many points do you use to fit the curve?
3. Could you send your source codes about the angle calculation to me?
Conference Paper Robust facet model for application to speckle noise removal
I use simple mathematical equation, please study math for this help. if you still face problem you can contact with me, then I will provide you the technique. thanks
Dear Sujan Chowdhury,
Have you read the paper of Speckle reduction in ultrasound images using nonisotropic adaptive filtering?
I get edges of original image by canny operation, and calculate the angle of the edge pixel-by-pixel following the tracing boundary method (the MatLab function is bwtraceboundary). The flow path is given as following:
The first step is using the canny operation to obtain the edges;
The second step is using the function bwtraceboundary to get coordination of pixels on an edges.
The third step is using the function polyfit three order polynomial.
The last step is the derivation of the polynomial and calculates the slop of tangent line of a pixel on the edge.
But I can't get right results which is different with results given in this paper. Do you give me some suggestions? Thanks!
My E-mail address is [email protected], and please reply me anytime.
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