Transmission

Generate a sinogram

FreeART offers a transmission projector to produce a sinogram from a phantom. You don t have to deal with the detector has FreeART will automatically setup the experimentation to define a detector at 180 degree from the incoming beam source.

From python

import freeart

# the simplest way to produce a sinogram from a phantom is the following call :
projector = freeart.TxFwdProjection(phantom, minAngle = 0, maxAngle = 2.0*np.pi, anglesNb = 40)
sinogram, angles = projector.makeSinogram()

Note

A larger example is given in freeart/python_utils/example_tx.py

From cpp

// setting up the geometry for the sinogram generation
algoIO.prepareSinogramGeneration(phantomFileName, 0.0, 2.0*M_PI, 125, phantom, sinosGeo);

// defining the transmission reconstruction (here to use double precision )
FreeART::SARTAlgorithm<double,FreeART::TxReconstruction>* al = new FreeART::SARTAlgorithm<double,FreeART::TxReconstruction>(phantom,sinosGeo);
// launch the projection
al->makeSinogram();
// get the sinogram generated
FREEART_NAMESPACE::GenericSinogram3D<double> sinogram = al->getSinogram();

Note

A larger example is given into examples/cpp/projector_tx.cpp

Reconstruction

For a transmission reconstruction you need :

• a sinogram matrix.
• the angle of acquisition of the given sinogram

From python

import freeart

# the simplest way to make a reconstruction fron a sinogram and a set of angles is :
reconstruction = freeart.TxBckProjection(_sinogram, _angles)
# set the relaxation factor. Key parameter for an ART reconstruction
reconstruction.setDampingFactor(0.02)
reconstructed_phantom = reconstruction.iterate(_nbIter)

From cpp

// set up the geometry (sinosgeo) and the stack of sinogram (sinos)
// from a sinoFile and an experiemt setup.
// Here because we are in the transmission case, the experiment setup can be empty of detector
algoIO.buildSinogramGeometry(sinoFile, esu, sinos, sinosGeo);

// create the transmission reconstruction
FreeART::SARTAlgorithm<double,FreeART::TxReconstruction> *al;
al = new FreeART::SARTAlgorithm<double,FreeART::TxReconstruction>(sinos,sinosGeo);
// launch the reconstruction over iterNb iterations
al->doWork(iterNb);

// get the reconstructed phantom
const FreeART::BinVec3D<double>* v = &(al->getPhantom());

Note

A more detailled example is given in the freeart/cpp_utils/projector_fluo.cpp file