Anti-Aliasing: Best Solution for Aliasing in Low Resolution RAW video Upscaling

[JuanIrache]

I tested some methods. To do so, I basically downscaled an image to 50%, upscaled it again with different plugins, and compared the results to the original image. Here's a detail of the comparison.

https://dl.dropboxusercontent.com/u/15481036/upscale.jpg

And here you can download the tiffs: https://dl.dropboxusercontent.com/u/15481036/images%20to%20compare.zip

Blow Up 3 is the only one that does something to aliasing. It does so by "destroying" the image and "creating a new similar one", in my opinion. I don't like the plastic look it gives, and I feel like it is inventing too much information and applying sharpness where there shouldn't be any. However, I wouldn't mind using it for some shots with bad aliasing and then mask out the non-aliased area. To my eye, the winner is S-Spline from Photo Zoom, the best results in both sharp and blurry areas, while respecting the look of the image.

I wrote some code to compare the images in a measurable way. Basically, the code tells you either how many pixels in the original image match the ones in the processed ones, or how different the different pixels are. The results were really disappointing. Basically it looks like only the Nearest Neighbour image shares around 30% of the information with the original image. The rest of them are mostly "invented". This might also be because there seems to be a small offset (less than a pixel?) between the original and the processed images.

Does anyone now of a method to make this comparison useful?

[Luiz Roberto dos Santos]

Just updating with new comparison make by Infognition.
Of course the test is questionable, and they should have used SSIM method for analysis, but I think valid post (really slow process, but good result with super-resolution):

http://www.infognition.com/articles/video_resize_shootout.html

[Audionut]

For upscaling, one of the eedi implementations.

http://avisynth.nl/index.php/AntiAliasing

[Luiz Roberto dos Santos]

For upscaling, one of the eedi implementations.

http://avisynth.nl/index.php/AntiAliasing

Try to see the link above... this compare EEDI3 with other methods. As I say, the Super Resolution generate more PSNR.
Of course, the EEDI is freeware (or open source?) script, and Video Enhancer not.

[Audionut]

Couple of things about that shootout.

They only measured PSNR.  There are plenty of other metrics available for testing.  Including some other metrics would have given a greater picture of performance.  PSNR is useful, don't get me wrong, but it is far from the be all, and end all, of video accuracy.

4x resize?  That's a little far removed what I would consider most people are aiming for.  And resizing all the way down to 480x270, has destroyed most detail.  This will favor any resizers which do a half assed job of retaining detail.  Combined with only PSNR measurement   

tritical's avisynth plugins are open sourced, the source code is available in downloads from his site.