What is the upper limit of the number of N-wires?

[hihihowareyou]

What is the upper limit of the number of N-wires?

I am trying to calibrate my probe with 8 group of wires.

So many groups are used becasue I am try to cover the image space by the wires so I can reduce the relative movement between the transducer and the phantom.

However, they are not recognized, though image quality is still OK.

I tried to change the config.xml, the detection alogrithm can only work when the upper 3 groups are left in it. Changing groups or add group number will make it fail again.

Any advise on large number of N-wires?

[lassoan]

All you need to do is to specify all the N-wires in your device set configuration file. The example configuration files contain 3 <Pattern Type="NWire"> elements. Your configuration will contain 8.

[hihihowareyou]

Hi Lassoan, If I put 8 patterns in the configuration like below, the wire detection can't work.

`  <Pattern Type="NWire">
    <Wire Name="  1:G10_G10" EndPointFront=" 29.8 0 45  " EndPointBack="  29.8 70 45  "/>
    <Wire Name="  2:F10_L10" EndPointFront=" 24.8 0 45  " EndPointBack="  54.8 70 45  "/>
    <Wire Name="  3:K10_K10" EndPointFront=" 49.8 0 45  " EndPointBack="  49.8 70 45  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  4:G9_G9" EndPointFront=" 29.8 0 40  " EndPointBack="  29.8 70 40  "/>
    <Wire Name="  5:L9_F9" EndPointFront=" 54.8 0 40  " EndPointBack="  24.8 70 40  "/>
    <Wire Name="  6:K9_K9" EndPointFront=" 49.8 0 40  " EndPointBack="  49.8 70 40  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  7:I8_I8" EndPointFront=" 39.8 0 35  " EndPointBack="  39.8 70 35  "/>
    <Wire Name="  8:H8_N8" EndPointFront=" 34.8 0 35  " EndPointBack="  64.8 70 35  "/>
    <Wire Name="  9:M8_M8" EndPointFront=" 59.8 0 35  " EndPointBack="  59.8 70 35  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  10:J7_J7" EndPointFront=" 44.8 0 30  " EndPointBack="  44.8 70 30  "/>
    <Wire Name="  11:O7_I7" EndPointFront=" 69.8 0 30  " EndPointBack="  39.8 70 30  "/>
    <Wire Name="  12:N7_N7" EndPointFront=" 64.8 0 30  " EndPointBack="  64.8 70 30  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  13:E6_E6" EndPointFront=" 19.8 0 25  " EndPointBack="  19.8 70 25  "/>
    <Wire Name="  14:D6_J6" EndPointFront=" 14.8 0 25  " EndPointBack="  44.8 70 25  "/>
    <Wire Name="  15:I6_I6" EndPointFront=" 39.8 0 25  " EndPointBack="  39.8 70 25  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  16:D5_D5" EndPointFront=" 14.8 0 20  " EndPointBack="  14.8 70 20  "/>
    <Wire Name="  17:I5_C5" EndPointFront=" 39.8 0 20  " EndPointBack="  9.8 70 20  "/>
    <Wire Name="  18:H5_H5" EndPointFront=" 34.8 0 20  " EndPointBack="  34.8 70 20  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  19:G4_G4" EndPointFront=" 29.8 0 15  " EndPointBack="  29.8 70 15  "/>
    <Wire Name="  20:L4_F4" EndPointFront=" 54.8 0 15  " EndPointBack="  24.8 70 15  "/>
    <Wire Name="  21:K4_K4" EndPointFront=" 49.8 0 15  " EndPointBack="  49.8 70 15  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  22:G3_G3" EndPointFront=" 29.8 0 10  " EndPointBack="  29.8 70 10  "/>
    <Wire Name="  23:F3_L3" EndPointFront=" 24.8 0 10  " EndPointBack="  54.8 70 10  "/>
    <Wire Name="  24:K3_K3" EndPointFront=" 49.8 0 10  " EndPointBack="  49.8 70 10  "/>
  </Pattern>`

If I change the configuration as below, it works.

  <Pattern Type="NWire">
    <Wire Name="  1:G10_G10" EndPointFront=" 29.8 0 45  " EndPointBack="  29.8 70 45  "/>
    <Wire Name="  2:F10_L10" EndPointFront=" 24.8 0 45  " EndPointBack="  54.8 70 45  "/>
    <Wire Name="  3:K10_K10" EndPointFront=" 49.8 0 45  " EndPointBack="  49.8 70 45  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  4:G9_G9" EndPointFront=" 29.8 0 40  " EndPointBack="  29.8 70 40  "/>
    <Wire Name="  5:L9_F9" EndPointFront=" 54.8 0 40  " EndPointBack="  24.8 70 40  "/>
    <Wire Name="  6:K9_K9" EndPointFront=" 49.8 0 40  " EndPointBack="  49.8 70 40  "/>
  </Pattern>
  <Pattern Type="NWire">
    <Wire Name="  7:I8_I8" EndPointFront=" 39.8 0 35  " EndPointBack="  39.8 70 35  "/>
    <Wire Name="  8:H8_N8" EndPointFront=" 34.8 0 35  " EndPointBack="  64.8 70 35  "/>
    <Wire Name="  9:M8_M8" EndPointFront=" 59.8 0 35  " EndPointBack="  59.8 70 35  "/>
  </Pattern>

Please note that I am using a customized phantom. I had succeed in one trail with 5 N-wire patterns, which are all aligned in horizontal direction. I think , one possible cause of the detection failure is the horizontal offset of the wires, how do you think?

[lassoan]

Probably you need to relax the tolerances

[hihihowareyou]

I had tried that too, still not work. I am wondering, whether the horizontal offset affect the line detection?

[hihihowareyou]

I had another setup, 5 patterns are positioned vertically, it works.
But when I introduce horizontal offset, it failed. You can check the plans as below.

[lassoan]

Probably the xml file does not match the actual geometry of the n-wires.

[hihihowareyou]

I am quite confident about the config.
You can check the screen shot below: the rows are quite accurate, but detection was not working. Even if I reduced the quantity of patterns to 4, (first 4 rows, quite accurate as you can see), detection still can't work.