Informatics Publishing Limited

T. Ashok Kumar ¹, S. Priya ², M. G. Mini ³

Affiliations
1 College of Engineering (A Govt. of Kerala Undertaking), Cherthala, Kerala, IN
2 Govt. Model Engineering College, Thrikkakara, Ernakulam, Kerala, IN
3 Department of Electronics Engineering, Govt. Model Engineering College, Thrikkakara, Ernakulam, Kerala, IN

Abstract

This paper presents an approach to the fast localization and extraction of optic disc from fundus images of the human retina. For the diagnosis of Diabetic Retinopathy and other eye related abnormalities, digital fundus images are becoming increasingly important. This fact opens the possibility of applying image processing techniques in ocular fundus images to facilitate and improve diagnosis in different ways. Optic disc is the major landmark for retinal fundus image registration and is indispensible for the quick understanding of retinal images. For the detection and subsequent extraction of optic disc, we first perform bit plane decomposition to the image. The lower order bit planes are found to carry vital information of the location and boundary of optic disc. Then we locate the exact boundary by means of mathematical morphology. The algorithm has been evaluated on a subset of MESSIDOR1 image database with various visual qualities. Robustness with respect to the changes of the parameters of the algorithm has been examined.

Keywords

Bit Plane Decomposition, Image Processing, Mathematical Morphology, Optic Disc Localization.

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T. R. Anoop ¹, M. G. Mini ¹

Affiliations
1 Department of Electronics and Communication Engineering, Model Engineering College, IN

Abstract

Fingerprint alteration is the process of masking one's identity from personal identification systems especially in boarder control security systems. Failure of matching the altered fingerprint of the criminals against the watch list of fingerprints can help them to break the security system. This fact leads to the need of a method for altered fingerprint matching. This paper presents a two stage method for altered fingerprint matching. In first stage, approximated global ridge orientation field of altered fingerprint is matched against the orientation field of its unaltered mate. If this matching is successful, fingerprints go to second stage. Second stage starts with the selection of unaltered region from the altered FP and same region from the unaltered mates. Matching in this stage is performed by extraction of ridge texture and ridge frequency from the selected region of interest. Euclidian distance is used in both stages to compute the matching score.

Keywords

Matching, Ridge Orientation, Ridge Texture, Ridge Frequency, Wavelet Transform.

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M. G. Mini ¹, T. R. Anoop ²

Affiliations
1 Model Engineering College, IN
2 Department of Electronics Engineering, Model Engineering College, IN

Abstract

Ridge orientation field is an important feature for fingerprint matching and fingerprint reconstruction. Matching of the altered fingerprint against its unaltered mates can be done by extracting the available features in the altered fingerprint and using it along with approximated ridge orientation. This paper presents a method for approximating ridge orientation field of altered fingerprints. In the proposed method, sine and cosine of doubled orientation of the fingerprint is decomposed using orthogonal wavelets and reconstructed back using only the approximation coefficients. No prior information about the singular points is needed for orientation approximation. The method is found suitable for orientation estimation of low quality fingerprint images also.

Keywords

Altered Fingerprints, Ridge Orientation, Ridge Texture, Ridge Frequency, Wavelet Transform.

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