Jun 18 2011

An improved parallel projection image reconstructor for Matlab

Tag: Implementation,softwareadmin @ 1:18 pm

This post describes a replacement for iradon for Matlab and Octave. The new function, CTrecon.m,

1. Fixes a bug in iradon that results in offsets from the true values in the reconstructed image.

2. Uses a mex function from iradon_speedy for backprojection. According to a comment by Jeff Orchard, the author of iradon_speedy, on the Mathworks File Exchange entry for iradon_speedy, Matlab R2011a now uses a mex function. I do not have that version so I cannot confirm this.

3. Handles complex projections to return a complex reconstructed image – see zBackproject.c

4. Regularizes the interface to (parameter-name’,parameter-value) syntax. This implies that CTrecon cannot just be dropped in for iradon. The advantage is more readable code.

more –>;

Jun 13 2011

The dimensionality of attenuation coefficients

Tag: Math,Physicsadmin @ 12:12 pm

In my previous post,  I showed how the singular value decomposition (SVD) can be used to study the effective rank of a matrix. In this post, I use the SVD to quantify the dimensionality of attenuation coefficients.

more –>;