BP(back projection) does not work properly for opposite stimulation protocol.

eitcom / pyEIT

Python based toolkit for Electrical Impedance Tomography

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BP(back projection) does not work properly for opposite stimulation protocol. #19

Closed ultrach closed 3 years ago

ultrach commented 3 years ago

Hi.

I tested the example "eit_dynamic_bp.py". It runs well at the default setting, but if I change the scanning conditions,

el_dist, step = 1, 1 ==> el_dist, step = 8, 1

the result is weird like as below. Figure_1

Does the BP solver not support the opposite stimulation protocol? or Is there anything i am missing?

Thank you in advance.

liubenyuan commented 3 years ago

Hi, Its a bug in BP normalization. I have updated the BP solver as well as the BP example.

Sorry for the inconvenience and the late reply.

ultrach commented 3 years ago

Hi. Thank you for your kind support. pyEIT is a great help to me.

liubenyuan commented 3 years ago

@ultrach It would be great if you cited our article in your research, haha.

ultrach commented 3 years ago

If I have an oppotunity, I'll gradly do that. By the way, the opposite protocol(el_dist=8, n_el=16) for bp solver result is still weired. TT

liubenyuan commented 3 years ago

Yeah, you can not assign n_el=16 if the total number of electrode is 16, in this way, the two nodes of voltage meter is a=i, b=(i+16)%16=i, which is the same electrode.