Deboeverie, Francis

English

Ghent University Academic Bibliography

A Uniform Approach for Face Segmentation andCoding with Adaptive Region GrowingFrancis DeboeverieDepartment of Telecommunication and Information Processing, Ghent UniversitySupervisor(s): Wilfried Philips, Peter VeelaertNowadays, it is the goal in visual communication applications, such as in smartphones and inautomated video conferencing, to send and store images of faces at a low bitrate, in such a way thatthe faces are still recognizable. Furthermore, it is essential that the representation is intelligent, sothat it can be used for face analysis.In this work we propose a novel technique to code and segment images of faces by 2-d polyno-mial surfaces. A face representation with polynomial surfaces is natural and offers a compact andreversible way to preserve the essence of the original face image. In order to have a complete cod-ing, the contours are coded by 1-d polynomial functions. On this manner, we efficiently representfaces in a hundred bytes instead of a hundred kilobytes. Transmitting these face parameters overthe network is very efficient, while preserving all the necessary details of the face. Furthermore, atreceiver side, these parameters are useful for face analysis.To segment the intensities of a face according to polynomial surfaces, we propose an intelligentsegmentation algorithm, which is a region growing algorithm based on constructive polynomialfitting. This constructive fitting works with a so-called infinity fitting cost, which is preferredover least squares, because it has the advantages of suitability for region growing and capabilityfor handling outliers. We also introduce adaptive thresholding for the constructive surface fitting,which allows a variable polynomial order and a variable segment thickness of the surfaces.Compression with polynomial surfaces is compared with JPEG. For minor image quality re-quirements, we achieve higher compression ratios, while presenting faces more recognizable,demonstrated in the results by higher rates for face detection and face recognition.

A uniform approach for face segmentation and coding with adaptive region growing

https://biblio.ugent.be/publication/2102407/file/2102434

A uniform approach for face segmentation and coding with adaptive region growing

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Ghent University Academic Bibliography