| cyl(r) | cone(r) | exponential(r) | gauss(r) |
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| airy(r) | sinc(r)^2 | (sinc(x)*sinc(y))^2 | tri(x)*tri(y) |
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source code: imdemo.cpp
The domain of these images is -2 <= (x, y) < 2
The sinc and airy functions above have a ring structure which can be seen more clearly by taking the logarithm of the image. The method is
v = (v>0.0? 1.0+log10(v)/decades: 0.0);
where v is a pixel value and
decades is the number of decades to stretch.
The images below were stretched with decades = 3
| airy(r) | sinc(r)^2 | (sinc(x)*sinc(y))^2 |
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source code for logarithmic enhancement: logim.cpp
The ring structure in the above images extends much further than the domain of those
images. We can use imdemo to produce images over a larger range. We also
make the images themselves bigger. For the airy function, the following commands were
used.
imdemo 4 bigdemo4.img 256 10 logim bigdemo4.img 3
The domain is now -5 <= (x, y) < 5
| airy(r) | sinc(r)^2 | (sinc(x)*sinc(y))^2 |
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Written by: John Loomis
E-Mail address: John.Loomis@notes.udayton.edu
Last updated: 17 Oct 1996