Amazing image conversion algorithms

A list of image processing algorithms whose intelligence level allows them to perform infinitely complex tasks.

From the simplest to the most difficult...

Depixelation of the image

Starting with a pixelated image, in other words, made of large squares, we come to a more accurate image, as if we could subsequently change the resolution of the screen on which they were drawn...

This can be very useful if you want to port an old game to a modern platform such as a smartphone or Canvas.

Implemented by Scale2X . HQX - a similar command line super resolution tool for enlarging images.

Change the image color to black and white

example of colorizing a black and white image

This technique is so well understood that old black and white films can now be replayed in color. This is explained in the article, Colorization Using Optimization, which provides several examples.

A tool available on GitHub also allows you to color a sketch from another image used as a model: Style2Paints. But in 2025, it became possible to ask ChatGPT 4o to color the image, and this is done automatically!

Restore an image or create an HDR

By intelligently removing "noise," in other words, image defects such as dots and scratches that must be correctly interpreted, the algorithm brings a damaged or faded image back to life.

It is implemented in a plugin for Gimp, G'Mic. This plugin can also create HDR automatically, i.e. sharpen both excessively bright and excessively dark areas.

Convert a photo to a drawing

This algorithm is also implemented in G'Mic.

Used from the command line, G'Mic allows numerous transformations, examples of which can be seen in the G'Mic gallery.

Seam thread

smart resizing

Intelligent algorithm for resizing images while maintaining the appearance of objects inside them. It is actually implemented in the resizing function of basic graphical utilities such as Gimp with the Liquid Rescale plugin and ImageMagik with the -liquid-rescale option.

Description.
JS Image Carver. Implemented in JavaScript.

Deleting an object

remove an object from a photo

This reaches its highest level. Starting with the rough outline of the object to be removed from the image, which may be a person or something else, the algorithm is able to identify the object in question, outline its exact outline, extrapolate what the background would be if the object were not present, and reconstruct the background, all without any human intervention.

This algorithm is available both in Gimp software, as an installation plugin, and in Photoshop.

Painting

By sketching and associating simplified objects with photographs, you can create a new image that naturally integrates those objects as if they were photographed.

This algorithm is implemented in Sketch To Photo software. You can download the command line program from the article.

Decorate your face

ItHe has a written rule that determines whether a face is beautiful or not, so the creators assume that what is closer to ordinary is more beautiful.
You can judge for yourself by comparing two versions of the same face in the photo, with the original face on the left and the computer-modified version on the right.

The algorithm has obvious applications in augmented reality, combined with technology that combines a camera with glasses to project an altered image of reality onto lenses.

Read more about this aesthetic intervention algorithm.