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nagadomi / waifu2x

Image Super-Resolution for Anime-Style Art
http://waifu2x.udp.jp/
MIT License
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"Medium" and "High" can look granier than "Low" on some images #368

Open NintendoManiac64 opened 3 years ago

NintendoManiac64 commented 3 years ago

On the waifu2x.udp.jp web app, when using the settings of "Medium" or "High" noise reduction + "Artwork" + "2x", some images will actually look grainier than "Low" noise reduction, especially so with the "High" noise reduction setting.

Worse still is that I was able to even replicate this issue in Snowshell whether set to "Waifu2x-converter-cpp" or "Waifu2x-Caffe" (I cannot test "Waifu2x-ncnn-Vulkan"), however with Snowshell this issue seems much less severe and, with "Medium" noise reduction, only exists a little bit in Snowshell.

The two attached images are the only source images (that is, before waifu2x processing) where I've run into this issue occurring (it's more noticeable with the first image however).

And the animated PNG at the bottom is a zoomed-in view of an area near the center of the first image demonstrating different levels of noise reduction arranged from most to least grainy (those not labeled as "Snowshell" were converted using the waifu2x.udp.jp web app).

psvita_op2title_2_opt psvita_op2title_opt animation

nagadomi commented 3 years ago

See #320

NintendoManiac64 commented 3 years ago

See #320

But wouldn't this then make the graininess be the same then between the web app and Snowshell?

Also for reference, the source images are not JPEGs but rather frames from an h.264 video.

nagadomi commented 3 years ago

I don't know the details of snowshell, but there are three versions of the waifu2x model: vgg7, upconv7 and cunet, with the older software uses vgg7 or upconv7. The web app uses cunet. Also, waifu2x's noise reduction expects only JPEG noise.