[daip] XSMTH

[Leonia Kogan]

Lynn,

Suppose we have 128 pixels at the first axis of the original image.
And you use NPOINTS=32. 

Then XSMTH will send into first axis of the output image  32 points.
Each of these 32 point is the result of the convolution of the input image 
with the convolved function having its maximum with step of 4 pixel.
I am not sure where does it start:
1,5,9.......125  or
2,6,10......126  or
.....
4,8,12......128

This is my understanding of the XSMTH codes.

Eric Greisen the author of the task will be here on Monday and he will be 
able to give you beter answer.

Leonid Kogan

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>From daip-admin at donar.cv.nrao.edu Thu Jul 24 07:33 MDT 2003
From: "Lynn D. Matthews" <lmatthew at cfa.harvard.edu>
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I have a question regarding the task XSMTH. In the case that OPCODE='smot'
and NPOINTS is set to some number smaller than the size of the original
vector, what algorithm is used to resample? Is every nth point simply
discarded, or is one of the interpolation algorithms used?

I noticed subtle differences between the case where I convolved with a
Gaussian with NPOINTS=0, then used linear interpolation (OPCODE='inte',
dparm(1)=0, NPOINTS=#) to reduce the number of points versus doing the
Gaussian smoothing and resampling in one step, so I want to be sure I
understand what the code is doing in each case.

Thanks,

Lynn
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