scholarly journals Application of Empirical Wavelet Transform in Digital Image Watermarking

2020 ◽  
Vol 37 (5) ◽  
pp. 839-845
Author(s):  
Mohammad Keivani ◽  
Amir Mahdi Sazdar ◽  
Jalil Mazloum ◽  
Akram Esvand Rahmani
Keyword(s):  
Wavelet Transform ◽  
Image Watermarking ◽  
Low Cost ◽  
Original Data ◽  
Point Of View ◽  
Security Requirements ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Empirical Wavelet Transform ◽  
Low Pass

Nowadays, rapid growth of the Internet and digital multimedia technologies make it possible to duplicate data without any loss of quality and at a very low cost. In this regard, manipulation of documents will easily be accomplished by applying digital art and without the copyright owner's permission. To deal with situation, more diverse security requirements are introduced every day. Watermarking is considered as one of the methods used for achieving this purpose. Watermarking is focused on inserting a subtle signal between the host media data somehow it does not change the original data, but they can be extracted if necessary. They are also used as a claim for ownership of the digital effect. Various methods have been presented for watermarking so far. These methods have been developed to overcome the weaknesses of previous methods. Empirical wavelet transform is taken into account as a new method for hiding and extracting military digital images with respect to alpha composition. As such, it is resistant to noise, low pass filter and compression. Analytical studies showed that this method is more efficient than other methods from quantitative and qualitative point of view.

Rapid Recovery of Wide-Bandwidth Photothermal Signals via Homodyne Photothermal Spectrometry: Theory and Methodology

1993 ◽  
Vol 47 (4) ◽  
pp. 489-500 ◽  
Author(s):  
J. F. Power ◽  
M. C. Prystay
Keyword(s):  
High Frequency ◽  
Low Cost ◽  
Signal Recovery ◽  
Wide Bandwidth ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Filter Output ◽  
Low Pass ◽  
Four Quadrant ◽  
Lock In

Homodyne photothermal spectrometry (HPS) is a very wide bandwidth signal recovery technique which uses many of the elements of lock-in detection at very low cost. The method uses a frequency sweep, with a high-frequency bandwidth of up to 10 MHz, to excite a linear photothermal system. The response sweep of the photothermal system is downshifted into a bandwidth of a few kilohertz by means of in-phase mixing with the excitation sweep with the use of a four-quadrant double-balanced mixer and a low-pass filter. Under conditions derived from theory, the filter output gives a good approximation to the real part of the photothermal system's frequency response, dispersed as a function of time. From a recording of this signal, the frequency and impulse response of the photothermal system are rapidly recovered at very high resolution. The method has been tested with the use of laser photopyroelectric effect spectrometry and provides an inexpensive, convenient method for the recovery of high-frequency photothermal signals.

An experimental analog circuit realization of Matsuda’s approximate fractional-order integral operators for industrial electronics

2021 ◽  
Author(s):  
Murat Koseoglu ◽  
Furkan Nur Deniz ◽  
Baris Baykant Alagoz ◽  
Ali Yuce ◽  
Nusret Tan
Keyword(s):  
Fractional Order ◽  
Analog Circuit ◽  
Low Cost ◽  
Electric Circuit ◽  
Partial Fraction ◽  
Circuit Realization ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Performance Improvements ◽  
Low Pass

Abstract Analog circuit realization of fractional order (FO) elements is a significant step for the industrialization of FO control systems because of enabling a low-cost, electric circuit realization by means of standard industrial electronics components. This study demonstrates an effective operational amplifier-based analog circuit realization of approximate FO integral elements for industrial electronics. To this end, approximate transfer function models of FO integral elements, which are calculated by using Matsuda’s approximation method, are decomposed into the sum of low-pass filter forms according to the partial fraction expansion. Each partial fraction term is implemented by using low-pass filters and amplifier circuits, and these circuits are combined with a summing amplifier to compose the approximate FO integral circuits. Widely used low-cost industrial electronics components, which are LF347N opamps, resistor and capacitor components, are used to achieve a discrete, easy-to-build analog realization of the approximate FO integral elements. The performance of designed circuit is compared with performance of Krishna’s FO circuit design and performance improvements are shown. The study presents design, performance validation and experimental verification of this straightforward approximate FO integral realization method.

Treatment of Noise in Experimental Transport Measurements Plots With Discrete Wavelet Transforms

2009 ◽  
Author(s):  
Rube´n Panta Pazos
Keyword(s):  
Wavelet Transform ◽  
Wavelet Transforms ◽  
Transport Theory ◽  
Discrete Wavelet ◽  
Transform Method ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Thresholding Algorithm ◽  
High Pass

In this work it is applied the wavelet transform method [2] in order to reduce diverse type of noises of experimental measurement plots in transport theory. First, suppose that a problem is governed by the transport equation for neutral particles, and an unknown perturbation occurs. In this case, the perturbation can be associated to the source, or even to the flux inside the domain X. How is the behavior of the perturbed flux in relation to the flux without the perturbation? For that, we employ the wavelet transform method in order to compress the angular flux considered as a 1D, or n-th dimensional signal ψ. The compression of this signal can be performed up to some a convenient order (that depends of the length of the signal). Now, the transport signal is decomposed as [9, 11]: ψ=〈am|dm|dm−1|dm−2|⋯|d2|d1〉 where ak represents the sub signal of k-th level generated by the low-pass filter associated to the discrete wavelet transform (DWT) chosen, and dk the sub signal of k-th level generated by the high-pass filter associated to the same DWT. It is applied basically the Haar, Daub4 and Coiflet wavelets transforms. Indeed, the sub signal am cumulates the energy, for this work of order 96% of the original signal ψ. A thresholding algorithm provides treatment for the noise, with significant reduction in the compressed signal. Then, it is established a comparison with a base of data in order to identify the perturbed signal. After the identification, it is recomposed the signal applying the inverse DWT. Many assumptions can be established: the rate signal-to-noise is properly high, the base of data must contain so many perturbed signals all with the same level of compression. The problem considered is for perturbations in the signal. For measurements the problem is similar, but in this case the unknown perturbations are generated by the apparatus of measurements, problems in experimental techniques, or simply by random noises. With the same above assumptions, the DWT is applied. For the identification, it is used a method evolving statistical and metric techniques. It is given some results obtained with an algebraic computer system.

scholarly journals Design of Reconfigurable Bandwidth Filtering Antenna and Its Applications in IR/UWB System

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 163
Author(s):  
Zhuohang Zhang ◽  
Zhongming Pan
Keyword(s):  
System Design ◽  
Time Domain ◽  
Low Cost ◽  
Impulse Radio ◽  
Dynamic Adjustment ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Compact Size ◽  
Low Pass ◽  
Communication Frequency

A reconfigurable bandwidth antenna for an impulse radio-UWB (IR/UWB) system design is illustrated in this paper. By adopting a continuously tunable low-pass filter by varactor at the feed of the antenna, the proposed antenna obtains a continuous tunable bandwidth from 1.02 GHz to 2.42 GHz. To ensure the identifiability of transmitted pulses in (IR-UWB) system, the antenna is analyzed in both frequency domain and time domain. The proposed antenna is valid with a system fidelity factor (SFF) above 0.8 while the bandwidth is tuning. The compact size, low cost, and tunable bandwidth with the identifiability of the transmitted pulse makes it suitable for UWB impulse radars to improve the utility ratio of frequency, and dynamic adjustment avoids interference of the IR-UWB in other communication frequency bands.

Scattering and information

1970 ◽  
Vol 268 (1185) ◽  
pp. 177-200 ◽  
Keyword(s):  
Structural Information ◽  
Speckle Noise ◽  
Quantitative Information ◽  
Sampling Interval ◽  
Point Of View ◽  
Partial Coherence ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Scattering Volume

The paper discusses some aspects of scattering of electromagnetic radiation in inhomogeneous media from the point of view of information theory. A theory is developed, based on a concrete model of a typical scattering experiment, which takes into account the finiteness of the scattering volume and the coherence characteristics of the radiation; as a conclusion, the speckle noise which is superimposed over the signal is brought into evidence. More exactly, it is shown that the spurious oscillations are due to the non-vanishing character of the convolution square of the inhomogeneity distribution function at the point of truncation in the primary space. Subsequently, the structural information of scattering experiments is examined and the finite logoncontent determined. The sampling interval is established and the resolution achievable in scattering measurements is deduced; also the means by which it can be improved are examined. An analysis of the quantitative information obtainable is pursued and the desirability of filtering is suggested. Finally, the way in which the partial coherence effectively acts as a low-pass filter is studied.

scholarly journals Design Engineering Instrumental Carotid Pulse System in Analitical Heart’s Dinamyc With Continuous Wavelet Transform Method

2016 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Eko Agus Suprayitno ◽  
Indah Sulistyowati ◽  
Izza Anshory ◽  
Jamaaluddin Jamaaluddin
Keyword(s):  
Wavelet Transform ◽  
Notch Filter ◽  
Design Engineering ◽  
Continuous Wavelet ◽  
Pulse System ◽  
Transform Method ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Quality Factor Q

Klasifikasi sinyal Carotid Pulse sangat penting untuk mengetahui proses terjadinya tekanan darah dalam mengalirkan darah melewati katup-katup jantung menuju ruang-ruang jantung dan paru-paru serta mendukung analisa suara jantung yang ada untuk mendeteksi murmur, mengklasifikasikan suara jantung normal dan tidak normal, serta untuk menjelaskan dinamika jantung, oleh sebab itu pada penelitian ini dilakukan beberapa pekerjaan pendahuluan pada pembuatan instrumentasi pendeteksian sinyal tekanan darah (Carotid Pulse).Pada penelitian ini dihasilkan informas Low Pass Filter Analog Orde 4 dengan frekuensi cutoff 100 Hz penguatan -3 dB terjadi di area frekuensi 120 Hz. Hasil uji Notch Filter dihasilkan tegangan output terkecil di frekuensi 50 Hz dengan besar Vout (0.14 ± 0.00) volt dengan Quality factor (Q) sebesar 6.28. Analisa sinyal Carotid Pulse dengan DFT memberikan informasi bahwa pada tekanan darah, area frekuensinya di antara 1 Hz sampai 20 Hz. Sinyal Carotid Pulse untuk siklus pertama Frekuensi tertingginya (6.81 ± 0.41) Hz dan merupakan gelombang P yang menggambarkan kenaikan Carotid Pulse secara tiba-tiba dari pemompaan darah pada ventrikel kiri menuju aorta hinggga mencapai puncak. Analisa dengan menggunakan CWT menghasilkan data keterangan waktu yang menunjukkan waktu terjadinya frekuensi tertinggi sinyal Carotid Pulse. Penelitian ini selanjutnya akan dikembangkan pada Multimodal Cardiac Analysis untuk mendapatkan informasi anatomi dan fisiologi jantung yang lebih kompleks.

Mode Decision Strategy for I-Frames in H.264/AVC Based on Low-Pass Filter

2011 ◽  
Vol 460-461 ◽  
pp. 810-815
Author(s):  
Huan Chang Qin
Keyword(s):  
Original Data ◽  
Mode Decision ◽  
Front Part ◽  
Decision Strategy ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Complicated Process ◽  
Low Pass ◽  
Data Partitions ◽  
The Difference

For the purpose of reduce the complicated process of H.264/AVC standard, the overall coding flow is studied, and some of the key technolies are discussed in the front part of this thesis. An algorithm for determining the distortion for different data partitions in H.264/AVC is proposed. A low-pass filter is implemented for each macroblock; after the macroblock is smoothed by this filter we compare the result of the filtered macroblock with the original data and generate the difference between them. Then the basic candidate-mode class is determined based on the difference, and the further mode decision can be made within this sub-class. So that the number of candidate modes is reduced, and the complexity of I-frame mode decision process is reduced.

Trajectory tracking compensation for teleoperation with transmission delays

Robotica ◽  
2011 ◽  
Vol 29 (6) ◽  
pp. 863-871 ◽  
Author(s):  
Lingyan Hu ◽  
Xiaoping P. Liu ◽  
Guoping Liu ◽  
Shaoping Xu
Keyword(s):  
Trajectory Tracking ◽  
Time Delays ◽  
Point Of View ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Transmission Delays ◽  
Additional Signal ◽  
Wave Variables ◽  
Reference Velocity ◽  
Low Pass

SUMMARYThe proper transmission of wave variables rather than power variables in teleoperation with time delays ensures system passivity – rendering the entire system stable, but the introduction of wave variables leads to distortion between the velocities/positions of the master and slave, and the performance deteriorates significantly with the increase of time delays. This paper presents a new compensating scheme implemented at the slave side to remove or cancel partially the distortion. The system passivity can still be maintained by tuning a properly designed low-pass filter. Compared with previous work, the main contribution of this work exists in two points: first, it is the actual velocity/trajectory of the slave rather than the reference velocity/trajectory of the slave that tracks the master one, so the quality of tracking is better and converges faster; second, the proposed compensator does not require any additional signal from the master side, minimizing the amount of data transmitted over the channel, which is very important from the practical point of view. The simulation and experiment results show that the velocity (or trajectory) tracking is significantly improved under the condition of stability, and the force presented to the user is close to the environment one, meaning a high degree of system transparency is achieved.

Application of Wavelet Digital Filter of Fourier Transform Profilometry in 3-D Measurement

2004 ◽  
Vol 471-472 ◽  
pp. 654-657
Author(s):  
Yun Shan Wang ◽  
S. Fu ◽  
Jin Quan Xu ◽  
Can Lin Zhou ◽  
S.C. Si ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Digital Filter ◽  
High Frequency ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Fourier Transform Profilometry ◽  
Low Pass ◽  
Phase Demodulation

Fourier transform profilometry in 3-D measurement based on wavelet digital filter is presented in this paper. Before phase demodulation, original modulated grating image is handled with wavelet transform in order to remove the background components and high frequency. This method resolves spectrum overlapping at some extent and reduces the requirement of low-pass filter.

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