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Varying image compression level spatially based on focal points

IP.com Disclosure Number: IPCOM000200993D
Publication Date: 2010-Nov-03
Document File: 1 page(s) / 47K

Publishing Venue

The IP.com Prior Art Database

Abstract

This article describes a technique for improving the perceived quality of a compressed image or video by varying the compression level spatially to reduce compression artefacts around focal points

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Varying image compression level spatially based on focal points

Disclosed is a technique for improving the perceived quality of a compressed image or video by varying the compression level spatially to reduce compression artefacts.

    Compression algorithms for images and video treat the uncompressed data in a uniform manner. This means they will treat the data as if its significance does not vary spatially, temporally (for video), or in other ways. This does not reflect the behaviour of the human visual system.

    When a human views an image or watches a video, their eyes naturally focus on certain areas of the image, and respond to particular shapes in the image differently. The human brain is well trained to process faces, for example. This means that even small amounts of distortion introduced by compression can make a face difficult to recognise, and if the person is speaking and the image of their mouth is distorted, can make following dialogue difficult.

    This is contrasted against other objects in the image, such as the background, textures of objects in the scene, and a person's clothing which the eye typically does not focus on and so increased compression distortion in these areas of the image might not significantly impact the perceived quality of the image or video.

    The technique takes advantage of focal points in an image or video to vary the compression level spatially across the image in order to reduce compression artifacts around these focal points.

    T...