Novelty is incremental. The major change over the baseline ResTv1 is the pixel-shuffle only, and the rest of the modifications are not new and cannot be one of the contributions.
Any intuitions or insights of why the architecture should be designed like this are missing: why the upsampling module should be involved? What can we learn from the architectural modifications from ResTv1 to RestV2 such as the block number at the first stage is halved.
Experimental justifications in Sections 3.4 and 4.3 do not seem to be enough backups for the explanation of the proposed architectural design. For example, Figure 3 tells us the upsampling module seemingly reduces the difference in the log amplitude between particular frequencies and the center frequency. However, this does not indicate the upsampling module is necessarily used. Furthermore, one may naturally ask the questions: 1) why do some specific frequencies only benefit from information recovery?; 2) If the upsampling module really helps information flow, shouldn't the entire frequency have the same effect?; 3) why the output-side layers do not benefit from it? Furthermore, Figure 4 is not clearly illustrated.
The details of Pixel-shuffle are not clearly presented. Is it the pixel-shuffle operation used in the super-resolution field? Then, why the dimensionality remains the same after upsampling in Figure 2. (b)?
The authors did not provide the limitations and potential negative societal impact of their work.
2) If the upsampling module really helps information flow, shouldn't the entire frequency have the same effect?;