What kind of technology allows you to improve images without loss (enlarge)?

Question

GIMP

According to some sites and / or marketers
, "There are many different ways to increase an image without losing quality ..."
I'm interested in real results, how to make a clear, distinguishable face from a photo in which the face is almost indistinguishable when it is enlarged (pixels), as if by increasing the most, I recently read that there is some kind of revolutionary program from one manufacturer, but I can’t find it

Answer 1

Because there are no such programs / algorithms, so you can’t find them.
There are algorithms and programs that implement them that make images SIMILAR to those that could be. The most obvious and simple is the conversion of a raster image into a vector image, followed by an increase. In some images, this can give a superficially very believable result.
There are more complex stochastic algorithms that use several low-resolution photos to create a higher-resolution photo. There, everything is based on the quantum effects of the fotik matrix, and I don’t understand this at all. Of course, it only works with raw, because it's not a good idea to increase jpg.
The whole question here is how important the accuracy of the increase is. It is impossible to make an HD photo of the eye from a daub of five pixels. But to increase twice, having received a reliable result, it is quite possible. But why?

Answer 2

Here's an example habrahabr.ru/post/147828
In general, have you seen the sharpen filter in Photoshop? This is what marketers most likely write about.

Answer 3

in any way without loss of quality,
yes, you can play with filters, increase sharpness, but in any case, this is all a loss of quality, you still can’t take the missing material out of thin air, in fact, you just take it and think it out programmatically so that it could probably be there.

Answer 4

SmartDeblur allows you to partially neutralize the blur effect. www.yuzhikov.com/projects.html

Answer 5

No loss, nothing. Any one of 3 effects will be visible: boundary halo, blurs or stepped contours.