Looking for image distortion algorithm

Recently I saw demonstration of image distortion algorithm that preserves some objects in image. For example changing weight/height ratio but preserving people faces in image to look realistically. The problem is i can't find the reference to that demonstration neither I know the name of such transformations.

Can anybody point me to a references to such开发者_开发百科 algorithms?

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Perhaps you are referring to liquid rescale?

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Seam carving is the current favourite. Liquid Rescale is an implementation of it.