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Lately, I've been trying to increase the quality of some of my images. I discovered rather quickly however that you can't fundamentally improve the quality of an image and that this was a common issue when scaling pictures.

I understand that this issue is born out of the fact that a computer doesn't know what's actually happening in a picture i.e. A man holding up three or two fingers and therefore scaling makes the picture appear blurry.

So I was wondering whether there was a software that could break down images into separate colour layers, for example, an image of a fox being broken down into separate maps of orange, dark orange, darker orange and white. Once the image had been broken into these layers, could you then scale them in unison so that the image doesn't blur? This method allows the image to scale while remembering a colour maps shape and colour value.

Is this a known method and will it work?

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  • Do you mean the same as described here: Vectorizing pixels in bitmap images for infinite resizing. Possible? ....in particular, read my answer. It sounds like what you're talking about is simply resizing images without any interpolation, which is of course possible and not unusual at all.
    – Cai
    Commented Nov 20, 2017 at 14:51
  • Vectorising raster images to enlarge them is really no better than just enlarging a raster image. This is the kind of thing you can expect. i.imgur.com/16ccfOc.png
    – Billy Kerr
    Commented Nov 20, 2017 at 15:17
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    An image is just an array of numbers. No matter what you do to an image, its data will always come from those original numbers. You can't recreate data which wasn't captured by the camera. The "color layers" you talk about... If they come from a normal image, they would consist of pixels, just like the original image, right? And they would scale the same way: Either chunky (nearest neighbor) or blurry (bicubic, among others). You can add noise, blur, sharpen, make every pixel circular or convert to vector, but you are not really adding data, merely camouflaging the loss of data when scaling.
    – Wolff
    Commented Nov 20, 2017 at 20:12
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    Data can not magically appear.
    – joojaa
    Commented Nov 20, 2017 at 20:19

3 Answers 3

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You're talking about Image Trace in Adobe Illustrator.

https://helpx.adobe.com/illustrator/using/tracing-artwork-live-trace-or.html

So I was wondering whether there was a software that could break down images into separate colour layers, for example, an image of a fox being broken down into separate maps of orange, dark orange, darker orange and white. Once the image had been broken into these layers, could you then scale them in unison so that the image doesn't blur?

You are describing Image Trace

It's not perfect. Image Trace is not going to add data back into the image that was not there. However, if you have a high enough quality image that is not overly complicated than Image Trace will break down your image to basic shapes and colors which will then allow you to resize the image without it becoming blurry.

Image Trace will not work as well with real photographs. No software exists that will do that. You have to do everything manually if you want to clean up a bad image.

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There are some resample algorithms that do something like that. For example, Benvista Photozoom has one called S-Spinline. Tries to predict a path instead of just pixels, and "invents" the in-between pixels according to it.

The result is good for some types of images, especially flat zones. But in some cases, it leaves a distinct rounded look.

On the image, A. 800% scaled original photo, B. Resampled with a simple bicubic algorithm, C. PhotoZoom S-Spinline.

enter image description here

It makes a good job avoiding blurriness on the edges but still can not invent new detail.

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Yes, this is the method GIF images use to reduce file size, and it works very well in many cases.

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    I don't think that's what he is asking at all
    – LateralTerminal
    Commented Nov 20, 2017 at 14:12
  • I could certainly be wrong, but I believe "separate maps of orange, dark orange, darker orange and white" is very close to what GIF color mapping does.
    – 13ruce
    Commented Nov 20, 2017 at 15:37
  • Sure, I agree that is how gif works. However, the asker wants to resize images without loosing quality. Gif does lose quality when you resize it. Converting an image to gif actually makes the quality of the image a lot worse. Anyway, gif is great for what it is. It's just not made to be scaled.
    – LateralTerminal
    Commented Nov 20, 2017 at 15:42
  • You can define a specific color table, (A map of specific color "layers"): - "A small color table may suffice for small images, and keeping the color table small allows the file to be downloaded faster. Both the 87a and 89a specifications allow color tables of 2n colors for any n from 1 through 8. Most graphics applications will read and display GIF images with any of these table sizes; but some do not support all sizes when creating images. Tables of 2, 16, and 256 colors are widely supported." -Wikipedia
    – 13ruce
    Commented Nov 20, 2017 at 15:42
  • "Is it possible to resize images without losing resolution" With gif? No, Gif is a raster format. Not a vector format. Maybe if we were talking about flash?
    – LateralTerminal
    Commented Nov 20, 2017 at 15:43

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