Legacy ImageMagick Discussions Archive

So I guess the way it works is:
my original image is 3264x2448.
by -define distort:viewport=3464x2648-100-100 we define a virtual background that has a border 100 pixel around my original image then we apply distort barrel "0.0301 -.0733 0" and this will only apply to the original image not the one ...

IT WORKED. THANK YOU FMW42 AND SNIBGO.

so that only works with square images. Right?

my image size is 3264 x 2448 what values should I use for distort:viewport?
Thanks.

Great. what does distort:viewport=800x800-300-300 and -trim and +repeat do?!
Thanks.

a=0.0301 (positive not negative)
b=-0.0733 (negative)
c=0

can you apply these parameters to your toes.png and get an output without loosing pixels?
Thanks,

except I don't want the cropping as it tries to keep the image resolution the same. Is there anyway to avoid that?

Use +distort rather than -distort.

see
http://www.imagemagick.org/Usage/distorts/#distort_bestfit
http://www.imagemagick.org/Usage/distorts/#distort_viewport




when I use ...

For a pure scale, you can multiply all four parameters by the same factor.

Is this really right?
let's say a=0.0301 b=-0.0733 and c=0 therefore d=1-(a+b+c)=1.0432
so I multiplied everything by 1.1
a=0.03311
b=-0.08063
c=0
d=1.14752

for a uniform scale I used this command:
convert source ...

Can excel solve the polynomial degree 4 equations?!

OH. Thanks again I didn't realize r' is source and r is the destination I was using it backward.
Interesting that when I changed the signs of a,b,c I got a visually correct result.
I have to try to solve for r in excel and re-plot.
Thanks again you have been very helpful.
r'=a.r^4+b.r^3+c.r^2+(1-a-b ...

one more thing.let's forget about scaling.
I have values for a kodak camera as a=0.0301 b=0.0733 c=0 and d=1-(a+b+c)
I ran the distorted image thru ptlens and convert.exe (imagemagik) and I am getting the same exact undistorted image result and as I expected the corner of image are pulling outward ...

I appreciate it. You have been very helpful Sir.
Thank you.

so we know that d=1-(a+b+c) will normalize based on smaller side of the image if I use 1.1 for d it will affect the distortion. Isn't that true?
I just want not to loose any data from my original image after removing distortion. your method works but it's affecting the solution.
in another word if I ...

So I am using this command to convert.exe" c:\kodak-cma.JPG -distort barrel "0.0301 -.0733 0" d:\corrected.jpg to create undistorted image.
and it works fine. except I don't want the cropping as it tries to keep the image resolution the same. Is there anyway to avoid that?
Thanks