2007/4

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    The Use of Wavelets in Image Interpolation: Possibilities and Limitations
    (Společnost pro radioelektronické inženýrství, 2007-12) Dumic, Emil; Grgic, Sonja; Grgic, Mislav
    Discrete wavelet transform (DWT) can be used in various applications, such as image compression and coding. In this paper we examine how DWT can be used in image interpolation. Afterwards proposed method is compared with two other traditional interpolation methods. For the case of magnified image achieved by interpolation, original image is unknown and there is no perfect way to judge the magnification quality. Common approach is to start with an original image, generate a lower resolution version of original image by downscaling, and then use different interpolation methods to magnify low resolution image. After that original and magnified images are compared to evaluate difference between them using different picture quality measures. Our results show that comparison of image interpolation methods depends on downscaling technique, image contents and quality metric. For fair comparison all these parameters need to be considered.
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    Novel Method for Color Textures Features Extraction Based on GLCM
    (Společnost pro radioelektronické inženýrství, 2007-12) Benco, Miroslav; Hudec, Robert
    Texture is one of most popular features for image classification and retrieval. Forasmuch as grayscale textures provide enough information to solve many tasks, the color information was not utilized. But in the recent years, many researchers have begun to take color information into consideration. In the texture analysis field, many algorithms have been enhanced to process color textures and new ones have been researched. In this paper the new method for color GLCM textures and comparing with other good known methods is presented.
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    Blind Source Separation Using Time-Frequency Masking
    (Společnost pro radioelektronické inženýrství, 2007-12) Mohammed, Abbas; Ballal, Tarig; Grbic, Nedelko
    In blind source separation (BSS), multiple mixtures acquired by an array of sensors are processed in order to recover the initial multiple source signals. While a variety of Independent Component Analysis (ICA)-based techniques are being used, in this paper we used a newly proposed method: The Degenerate Unmixing and Estimation Technique (DUET). The method applies when sources are W-disjoint orthogonal; that is, when the time-frequency representations, of any two signals in the mixtures are disjoint sets. The method uses an online algorithm to perform gradient search for the mixing parameters, and simultaneously construct binary time-frequency masks that are used to partition one of the mixtures to recover the original source signals. Previous studies have demonstrated the robustness of the method. However, the investigation in this paper reveals significant drawbacks associated with the technique which should be addressed in the future.
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    Using of Hand Geometry in Biometric Security Systems
    (Společnost pro radioelektronické inženýrství, 2007-12) Varchol, Peter; Levicky, Dusan
    In this paper, biometric security system for access control based on hand geometry is presented. Biometric technologies are becoming the foundation of an extensive array of highly secure identification and personal verification solutions. Experiments show that the physical dimensions of a human hand contain information that is capable to verify the identity of an individual. The database created for our system consists of 408 hand images from 24 people of young ages and different sex. Different pattern recognition techniques have been tested to be used for verification. Achieved experimental results FAR=0,1812% and FRR=14,583% show the possibilities of using this system in environment with medium security level with full acceptance from all users.
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    On the Relationship between Integer Lifting and Rounding Transform
    (Společnost pro radioelektronické inženýrství, 2007-12) Prochaska, Jan; Vargic, Radoslav
    In this paper we analyze the relationship between integer Lifting scheme and Rounding transform as means to compute the wavelet transform in signal processing area. We bring some new results which better describe relationship, reversibility and equivalence of integer lifting scheme and rounding transform concept.