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Please teach me why wallfilter is IIR.

My name is Masatoshi nakashima,

I am learning ultrasound signal processing.

Please teach me about  wallfilter algorithm.  

In Application Report SPRAB11–November 2008
"Efficient Implementation of Ultrasound Color Doppler
Algorithms on Texas Instruments’ C64x™ Platforms",
there is a explanation of wallfilter.
"This module does an IIR filtering operation.
The basic operation done for filtering for each scan-line set is a multiplication of complex input
data matrix, X, with real coefficient matrix, W, given by,
Y DxN =X DxN  *    W NxN      "

I can not understand why this equation expresses IIR.  I think IIR should have feedback input.
(1) Please teach me, what is feedback element in this matrix conversion equation.
(2)Please teach me, how to design W matrix. 
Please  pardon me for my  poor knowledge.
regards.


  •  This is a follow by myself.   I read "Clutter Filter Design for Ultrasound Color Flow Imaging",

    I understood IIR design method  a little.

    (1) what initialization method is adopted in the  wall filter of MIDAS demo V3?

    (2) Please teach the design  parameter of  the wall fileter of MIDAS demo v3.

    thank you.

  • Expert 4920 points

    In reply to masatoshi nakashima:

    Masatoshi,

    This post should answer your 2 questions:

    http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/439/t/149912.aspx#541961

    - Uday

    --- If you need more help, please reply. If this answers your question, please Verify Answer below this post ---

  • In reply to Uday:

    Mr. Gurani:

    Thank you for your answer. I read the post which was shown me.

    But  I can not found wf_coeff.m. 

    Please teach me where it is. 

    And I can not found(understand ) the method of the filter initialization in the post.

    Thank you.

  • In reply to Uday:

    Dear Mr. Gurnari,

     I have read the post that you show me. 

    I can not find wf_coeff.m . Please teach me where it is.

    Thank you.

  • Expert 4920 points

    In reply to masatoshi nakashima:

    The STK-MED that the e2e post refers to is the Medical Imaging Software Toolkit (STK-MED). You can download the latest STK-MED v3.0 from http://www.ti.com/tool/s2meddus and the file is located at 'stk-med-03.xx.xx.xx\miAlgos\dpu\test\vectors\wf_coeff.m'

    - Uday

    --- If you need more help, please reply. If this answers your question, please Verify Answer below this post ---

  • In reply to Uday:

    Mr.Gurnani:

     Thank you for your quick answer. I have read wf_coff.m.

    I  have understood this filtering. 

    Thank you again.

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