lecture06: 2D filters, and Linear systems
http://www.owlnet.rice.edu/~elec539/Projects97/morphjrks/moredge.html
http://www.owlnet.rice.edu/~elec301/Projects00/tomography/R_intro.htm
http://www.oal.whoi.edu/tomo2.html
http://archaeology.huji.ac.il/ct/
http://www.triumf.ca/welcome/petscan.html
http://www.tomography.umist.ac.uk/intro.shtml
http://www.itso.ru/GEOTOMO/paper_moscow2003/index.html
http://internal.maths.adelaide.edu.au/people/mroughan/traffic_matrices.html
http://www.owlnet.rice.edu/~elec301/Projects00/tomography/code.htm
http://www.radiologyinfo.org/photocat/photos.cfm?image=hd-ct-perfusion.jpg
&&subcategory=Head&&stop=9
http://eivind.imm.dtu.dk/staff/ptoft/Radon/Radon.html
http://mathworld.wolfram.com/RadonTransform.html
http://eivind.imm.dtu.dk/staff/ptoft/Radon/Radon.html
http://www.anc.ed.ac.uk/~amos/hough.html
http://www.owlnet.rice.edu/~elec301/Projects00/tomography/code.htm