# COMPARISON BETWEEN MEXICAN HAT AND HAAR WAVELET DESCRIPTORS FOR SHAPE REPRESENTATION

### Adnan Abou Nabout, Bernd Tibken

#### 2009

#### Abstract

The wavelet transformation is a well known method in several engineering fields. In image processing and pattern recognition the wavelet transformation is used for the recognition of object shapes by deriving so called wavelet descriptors. In this context the Mexican Hat as well as the Haar function were used as mother wavelets. To derive wavelet descriptors the methods use a periodical angle function derived from the contour polygon. The angle function describes an object shape by calculating the angle changes along the object contour beginning from a given starting point. Since object shapes are described by polygons, the angle function is step-shaped and therefore it includes discontinuity at the existing polygon corners. This causes big changes of the Haar wavelet descriptors if the positions of the polygon corners change due to small changes of the object shape. Such changes can be caused at least by digitalization or binarization errors. The Mexican Hat wavelet descriptors are more adapted and suffer however from small changes. In this paper we present the results of the comparison between both methods in there accurateness of describing object shapes.

#### References

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#### Paper Citation

#### in Harvard Style

Abou Nabout A. and Tibken B. (2009). **COMPARISON BETWEEN MEXICAN HAT AND HAAR WAVELET DESCRIPTORS FOR SHAPE REPRESENTATION** . In *Proceedings of the 6th International Conference on Informatics in Control, Automation and Robotics - Volume 1: ICINCO,* ISBN 978-989-674-000-9, pages 214-221. DOI: 10.5220/0002207002140221

#### in Bibtex Style

@conference{icinco09,

author={Adnan Abou Nabout and Bernd Tibken},

title={COMPARISON BETWEEN MEXICAN HAT AND HAAR WAVELET DESCRIPTORS FOR SHAPE REPRESENTATION},

booktitle={Proceedings of the 6th International Conference on Informatics in Control, Automation and Robotics - Volume 1: ICINCO,},

year={2009},

pages={214-221},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0002207002140221},

isbn={978-989-674-000-9},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the 6th International Conference on Informatics in Control, Automation and Robotics - Volume 1: ICINCO,

TI - COMPARISON BETWEEN MEXICAN HAT AND HAAR WAVELET DESCRIPTORS FOR SHAPE REPRESENTATION

SN - 978-989-674-000-9

AU - Abou Nabout A.

AU - Tibken B.

PY - 2009

SP - 214

EP - 221

DO - 10.5220/0002207002140221