Forums > Jitter

need how to for good quality image scaling

January 7, 2012 | 7:13 am

It seems basic, but I can’t find a satisfying setting for an image I simply scale to the screen size.
I have a book page scanned with a resolution of 2740 * 4222 pixels. Its mainly text I want to be able to read it. I display it with a jit.pwindow. The result is always very pixelated and badly readable. If I look at the same picture in Preview I can easily read it. and it looks at least 1000 times better.
How do I get the same display quality in Jitter? Or how do I downsize a picture in good quality in general? There won’t be a speed issue, its just an image, no video…
I want to avoid to do it outside Max…

Any help appreciated

Stefan


January 7, 2012 | 5:53 pm

How does it look with [fpic]?


January 7, 2012 | 9:57 pm

This patch doesn’t do any magic tricks to enhance clarity, but it does ensure that your viewing window has the correct aspect ratio for the image you’re trying to view.

– Pasted Max Patch, click to expand. –

January 8, 2012 | 12:17 pm

I use this to be sure each qt movie is auto-displayed fullscreen with the good ratio

– Pasted Max Patch, click to expand. –

January 8, 2012 | 10:17 pm

Thanks for the answers, its seems Jitter isn’t capable or those who know how to do it did not come across.
The tip with fpic was the solution. That looks completely fine for me…

Stefan


January 9, 2012 | 12:56 am

Hi Stefan

Whilst I haven’t looked into this myself just yet, I have come across similar problems and believe that the solution may lie in doing some texture filtering on the GPU. The following link may help?

http://http.developer.nvidia.com/GPUGems/gpugems_ch24.html

Like I said though, I haven’t really tried anything like this just yet

DiGiTaLFX


January 9, 2012 | 1:06 am

Use @adapt 1 for jit.qt.movie to read the image? A jit.pwindow @interp 1 is going to scale the image down using linear filtering. Default, if I recall, is @interp 0, i.e.: nearest neighbor filtering. Why not use a fullscreen jit.window so you can see it nicely? Send us the patch you are using, so we can critique it, otherwise we are working in the dark.


January 9, 2012 | 7:07 am

It’s good to know that fpic scales images nicely. For a Jitter solution, using the correct aspect ratio, upsampling (with interpolation) to a size that is a whole number multiple of your window size, then downsampling with interpolation should give the best result. But I think I’m correct in saying that jit.gl.videoplane takes care of the sizing issue for you, and scales image size down using averaging (as opposed to nearest neighbor), giving a pretty good antialiased image. Here’s a quick example.

– Pasted Max Patch, click to expand. –

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