Wavelet for fix seams and even colors

[rhurta]

The stableSR upscaler have an option to fix colors and seams using wavelet.
From its github (https://github.com/pkuliyi2015/sd-webui-stablesr)
Wavelet decomposes the original and the outcome images into low and high frequency, and then replace the outcome image's low-frequency part (colors) with the original image's. This is very powerful for uneven color shifting. The algorithm is from GIMP and Krita, which will take several seconds for each image.
The results of this process are quite good. but I still prefer Ultimate SD Upscaler as its friendlier with low end cards and low memory as mine (GTX960M with 4GB VRAM)