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Comment by ricardobeat | Hacker News Reader

This is amazing. Not only it completely blows JPEG and BPG out of the water in efficiency, but it makes some images look better than the original! It seems to reduce local contrast which works well for skin (photos 1, 2 and 5), and what it does for repeating patterns is quite pleasant to the eyes (1 and 4).

The only downside I see is the introduction of artifacts like you can see on the right-side face of the clock tower.

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Thanks for the kind words!

We hope that the algorithm we presented is a step in the right direction, and we acknowledge that there's more work to be done! Just like with any algorithm there are ways in which it can be improved. Please check out the supplementary materials [1], to find some examples that can definitely be improved: small faces and small text. Overall, as you say, the algorithm does a great job though!

[1] https://storage.googleapis.com/hific/data/appendixb/appendix...

> it makes some images look better than the original! It seems to reduce local contrast which works well for skin (photos 1, 2 and 5)

It's better than the lossy JPEGs but I strongly disagree it's better than the original - or even close. Examining image 1 closely, the loss of contrast and the regularising of the texture of the skin make the HiFIC image feel fake when I look at it. I downloaded and opened the images at random on my computer to get rid of the bias of "the right one is the original" and it was the original I preferred each time.

Regardless, it's impressive work and I look forward to future developments!

That effect is very close to what a photographer would aim for with manual editing. It is not about fidelity but that blemish-free look which you'll find on any magazine. The authors also mentioned that in their research most users preferred the compressed one!

To me the effect looks like when heavy chroma noise filtering is applied, leaving luminance noise. This is particularly noticeable in image 2 all over the face; it's nothing like the blemish-free look we strive for when post-processing portraits or fashion photography.

How about image 2? On both of my monitors, the colors in the regenerated image have a striking subjective advantage over the original. I'd be surprised if 95%+ of observers didn't favor the compressed version of image 2.

Checked on 2 monitors here (one color calibrated) and I see the HiFiC version of image 2 has slightly more muted colours than the original.

Unclear what you're seeing to get "striking subjective advantage" but it's not visible here.

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