2012/4

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    Current-Mode Universal Filters Employing Single FDCCII
    (Společnost pro radioelektronické inženýrství, 2012-12) Kacar, Firat; Yesil, Abdullah; Kuntman, Hakan
    In this study, to realize current-mode multifunction filters, three new circuit configurations are presented. The circuits include fully differential current conveyor (FDCCII) and four passive components. First proposed circuit is a universal filter with single-input and three-outputs, which can simultaneously realize current mode low-pass, band-pass and high-pass filter responses employing all grounded passive components. The last two proposed are universal filters with three-inputs single-output, which can realize current mode low-pass, band-pass, high-pass, band-stop and all-pass filter responses employing single FDCCII. Furthermore, each of the proposed circuits still enjoys realization using a minimum number of active and passive components. First and last of the proposed circuits have no requirement with the component choice conditions to realize specific filtering functions. No parameter matching condition is required. Active and passive sensitivities of filters are investigated and calculated 5 percentage hangings. Simulation results are found in close agreement with the theoretical results.
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    Graph Cuts based Image Segmentation using Fuzzy Rule Based System
    (Společnost pro radioelektronické inženýrství, 2012-12) Khokher, Muhammad Rizwan; Ghafoor, Abdul; Siddiqui, Adil Masood
    This work deals with the segmentation of gray scale, color and texture images using graph cuts. From input image, a graph is constructed using intensity, color and texture profiles of the image simultaneously. Based on the nature of image, a fuzzy rule based system is designed to find the weight that should be given to a specific image feature during graph development. The graph obtained from the fuzzy rule based weighted average of different image features is further used in normalized graph cuts framework. Graph is iteratively bi-partitioned through the normalized graph cuts algorithm to get optimum partitions resulting in the segmented image. Berkeley segmentation database is used to test our algorithm and the segmentation results are evaluated through probabilistic rand index, global consistency error, sensitivity, positive predictive value and Dice similarity coefficient. It is shown that the presented segmentation method provides effective results for most types of images.
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    Tunable Versatile High Input Impedance Voltage-Mode Universal Biquadratic Filter Based on DDCCs
    (Společnost pro radioelektronické inženýrství, 2012-12) Horng, Jiun-Wei; Chiu, To-Yao; Jhao, Zih-Yang
    A high input impedance voltage-mode universal biquadratic filter with three input terminals and seven output terminals is presented. The proposed circuit uses three differential difference current conveyors (DDCCs), four resistors and two grounded capacitors. The proposed circuit can realize all the standard filter functions, namely, lowpass, bandpass, highpass, notch and allpass, simultaneously. The proposed circuit offers the features of high input impedance, using only grounded capacitors, and orthogonal controllability of resonance angular frequency and quality factor.
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    Evolutionary Synthesis of Fractional Capacitor Using Simulated Annealing Method
    (Společnost pro radioelektronické inženýrství, 2012-12) Slezak, Josef; Goetthans, Tomas; Drinovsky, Jiri
    Synthesis of fractional capacitor using classical analog circuit synthesis method was described in [6]. The work presented in this paper is focused on synthesis of the same problem by means of evolutionary method simulated annealing. Based on given desired characteristic function as input impedance or transfer function, the proposed method is able to synthesize topology and values of the components of the desired analog circuit. Comparison of the results given in [6] and results obtained by the proposed method will be given and discussed.
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    A Non-blind Color Image Watermarking Scheme Resistent Against Geometric Attacks
    (Společnost pro radioelektronické inženýrství, 2012-12) Ghafoor, Abdul; Imran, Muhammad
    A non-blind color image watermarking scheme using principle component analysis, discrete wavelet transform and singular value decomposition is proposed. The color components are uncorrelated using principle component analysis. The watermark is embedded into the singular values of discrete wavelet transformed sub-band associated with principle component containing most of the color information. The scheme was tested against various attacks (including histogram equalization, rotation, Gaussian noise, scaling, cropping, Y-shearing, X-shearing, median filtering, affine transformation, translation, salt & pepper, sharpening), to check robustness. The results of proposed scheme are compared with state-of-the-art existing color watermarking schemes using normalized correlation coefficient and peak signal to noise ratio. The simulation results show that proposed scheme is robust and imperceptible.