Is it or will it be possible to upscale to custom resolution? about waifu2x

[Saren-Arterius]

If you need 1.5x, you can first resize your image by (1.5/1.6)x using photoshop, then resize it using waifu1.6x, lol.
I think it's because the algorithm's limitation actually.

[Zotikus1001]

Yes, I could do that, but its more work on top..

I wanted to know if it is possible, or if its limited to that because of the algorithm..
It may be limited right now, but it may be possible to get it working on different x scales..

[drdaxxy]

There is only Waifu2x. The 1.6x scale setting on the webinterface just scales down from 2x to 1.6x using a more conventional image filter.

Don't know whether it's practical to scale to different factors by changing a few parameters and using different training images, haven't really looked at the code much.

[nagadomi]

The pre-trained model of waifu2x supports only 2x-scaling.
Implementation of 1.6x scaling is here.
https://github.com/nagadomi/waifu2x/blob/master/web.lua#L150

-- upscaling 2x
x = apply_scale2x(x) 
-- downscaling to custom resolution with generic image scaling algorithm.
x = iproc.scale(x, x16[1], x16[2], "Jinc")

[RockNHawk]

So if I want to upscale to like 5x , I should training a new model ?

[RockNHawk]

@nagadomi

[nagadomi]

You can apply 2x consecutively. 2x->4x->8x->5x(downscaling), but it will not get much better results.

[RockNHawk]

Thanks !😋