Different reconstruction algorithms in diffuse optical tomography may result in different image qualities due to the nature of inverse problem that is underestimated and ill-conditioned. A dual-heterogeneity model is presented and the Rytov solution to the diffusion approximation equation is employed
where the scattered field is assumed to be slowly variable in space. Furthermore
the scattering coefficient μs is regarded as a known spatially constant
and thus
the reconstruction of the absorption coefficient μa is solely focused on. Data simulated from the dual-heterogeneity model at various conditions are used to investigate spatial resolution
time consumption for imaging and noise sensitivity of four common reconstruction techniques respectively. The comparative research indicates that Tikhonov method is superior to the other three methods in the performance of spatial resolution when the noise gets relatively low. The truncated singular value decomposition(TSVD)is the most insensitive to noise as the signal to noise ratio is less than 20 dB. When the positions of sources and detectors
the region of interest
and the volume of each voxel are fixed
Tikhonov method takes the least time to image. Generally
the performance of the subspace techniques is better than the one of the algebraic techniques in the aspects mentioned above.
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