The shape of the T1 image and the shape of the electric field are different

[bryn]

but are you using a slice field viewer to show the interpolated MRI slice? If not you basically are looking at the original MRI, with different grid and data ordering.

[lucky_lin]

@bryn I don't know how to use the slice viewer to inspect the T1 image. I just want to export it.

[bryn]

I sent you code (it can also be done in GUI) above to interpolate the T1w image onto the E-field/simulation grid. If you do that you can export it in the same format as you export the E-field (not as a nii.gz file, since the simulation grid is rectilinear which is not supported by nifti files).

[lucky_lin]

@bryn Is the following code correct? I'm not sure if the input is correct.

inputs1 = [model_to_grid_filter.Outputs[""]]
field_data_text_exporter1 = analysis.exporters.FieldDataTextExporter(inputs=inputs1)
field_data_text_exporter1.FileName = output_file1
field_data_text_exporter1.UpdateAttributes()
document.AllAlgorithms.Add(field_data_text_exporter1)
field_data_text_exporter1.Update(overwrite=True)

[bryn]

this does not include the interpolation...

to access an output of an analysis algorithm you can use named outputs or indexed outputs, in your snippet above it may be easier to use the index '0'.

inputs1 = [model_to_grid_filter.Outputs[0]]

[lucky_lin]

@bryn Thank you!!! I'll give it a try！^^

[lucky_lin]

@bryn After executing the code, an error occurred that prevented the export of the txt file.

[bryn]

looking at the error 'Unable to create destination file', I would guess you are trying to write to a directory that does not exist (yet) or without write permissions

[lucky_lin]

However, the electric field data can be exported.

[bryn]

what does your code look like? I create the pipeline in the GUI and it seems to run fine for me (v9.0.0). The "To Python" function yields

# This script was auto-generated by Sim4Life version 9.0.1

import numpy
import s4l_v1.analysis as analysis
import s4l_v1.document as document
import s4l_v1.model as model
import s4l_v1.units as units
from s4l_v1 import ReleaseVersion
from s4l_v1 import Unit

try:
    # Define the version to use for default values
    ReleaseVersion.set_active(ReleaseVersion.version9_0)
    
    # Creating the analysis pipeline
    # Adding a new ModelToGridFilter
    inputs = []
    model_to_grid_filter = analysis.core.ModelToGridFilter(inputs=inputs)
    model_to_grid_filter.Name = "IXI025-Guys-0852-T1"
    model_to_grid_filter.Entity = model.AllEntities()["IXI025-Guys-0852-T1"]
    model_to_grid_filter.UpdateAttributes()
    document.AllAlgorithms.Add(model_to_grid_filter)

    # Adding a new SimulationExtractor
    simulation = document.AllSimulations["EM"]
    simulation_extractor = simulation.Results()

    # Adding a new EmSensorExtractor
    em_sensor_extractor = simulation_extractor["Overall Field"]
    em_sensor_extractor.FrequencySettings.ExtractedFrequency = u"All"
    document.AllAlgorithms.Add(em_sensor_extractor)

    # Adding a new FieldInterpolationFilter
    inputs = [model_to_grid_filter.Outputs[0], em_sensor_extractor.Outputs["EM E(x,y,z,f0)"]]
    field_interpolation_filter = analysis.core.FieldInterpolationFilter(inputs=inputs)
    field_interpolation_filter.UpdateAttributes()
    document.AllAlgorithms.Add(field_interpolation_filter)

    # Adding a new FieldDataTextExporter
    inputs = [field_interpolation_filter.Outputs[""]]
    field_data_text_exporter = analysis.exporters.FieldDataTextExporter(inputs=inputs)
    field_data_text_exporter.FileName = u"D:\\temp\\ExportedFieldData-T1w.txt"
    field_data_text_exporter.UpdateAttributes()
    document.AllAlgorithms.Add(field_data_text_exporter)

except Exception as exc:
    import traceback
    traceback.print_exc()
    # Reset active version to default
    ReleaseVersion.reset()
    raise(exc)

[lucky_lin]

This post is deleted!

[bryn]

your code is still not using the FieldInterpolationFilter to interpolate the T1w image onto the same grid as the E-field. Note, the FieldDataTextExporter takes the output of the interpolator as input