jixiaozhong / RealSR

Real-World Super-Resolution via Kernel Estimation and Noise Injection
Apache License 2.0
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question about clean-up using bicubic downsampling #26

Closed fedral closed 3 years ago

fedral commented 3 years ago

Hi, I have a question about clean-up section. realSR "adopt bicubic downsampling on the real image in the source domain to remove noise and make the image sharper".

But I think bicubic downsampling preserve as much information as possible, including noise and content, but rather than "remove noise". I tested on DIV2K train image 0048.png, which has severe noise. area / bicubic / bilinear downsampled 720*720 images are compared.

image

bicubic downsampled [bottom left] same visual quaility as HR; area downsampled [top right] eliminate most background noise; bilinear downsampled [bottom right] slightly denoise ;

did I miss something?