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Radon parameters [message #40223]

Mon, 26 July 2004 10:28

Tim[1]
Messages: 4
Registered: June 2004

Junior Member

Dear all,

This sort of question has come along before, but I'm still not able to give
the correct parameters to the RADON function.

The situation is as follows. I have 73 experimentally obtained projections
of an object, each 193 by 193 pixels. This should give me 193 sinograms,
each 193 by 73 pixels. For each sinogram, I wish to produce a
backprojection, and I can do this using the obsolete RIEMANN command, but
I'd like to do so with the RADON function eg,

IDL> bp = RADON(/backprojection, sinogram, THETA=theta, RHO=rho)

The 73 projections were taken over an angular range -70 degrees to +74
degrees, with 2 degree increments. I am thus setting 'theta' using,

IDL> theta=(2*FINDGEN(73) - 70) * !DTOR

But, what of rho? I think that this should be a vector of 73 elements, but I
can't fathom the rationale behind how it should be formed. RADON reports
that "ARRAY, RHO, or THETA dimensions are incompatible", and I'm pretty sure
the RHO's to blame.

Any advice?

Thanks,

Tim

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[Message index]

		Radon parameters By: Tim[1] on Mon, 26 July 2004 10:28
		Re: Radon parameters By: Timm Weitkamp on Sat, 31 July 2004 03:27

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