Temat: fractional transform

Skocz do pozycji: 1.

Tytuł:: Double-image encryption algorithm based on discrete fractional angular transform and fractional Fourier transform
Autorzy:: Qiu, Tian
Dai, Wei-Hua
Chen, Su-Hua
Zhou, Hang
Gong, Li-Hua
Tematy:: chaotic system
fractional transform
discrete fractional angular transform
double-image encryption; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/2172857.pdf Link otwiera się w nowym oknie
Opis:: By combining fractional Fourier transform with discrete fractional angular transform, a double-image encryption algorithm is designed. The discrete cosine transform is performed on two grayscale images to generate a spectrum image, and then the generated spectrum image is compressed into an image with Zigzag scanning. The compressed image is processed with the discrete fractional angular transform, and then fractional Fourier transform and double random phase coding are executed on the image. The DNA operation controlled by chaotic system is introduced to change the pixel values. Finally, the ciphertext image is obtained through bit-level permutation and pixel adaptive diffusion. The statistical information of the plaintext images is employed as the input of the SHA-256 to calculate the initial conditions of the chaotic map. Simulation experiments demonstrate that the double-image encryption algorithm can effectively reduce the correlation among adjacent pixels of the plaintext images.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Certain properties of continuous fractional wavelet transform on Hardy space and Morrey space
Autorzy:: Verma, Amit K.
Gupta, Bivek
Tematy:: fractional Fourier transform
continuous fractional wavelet transform
Hardy space
Morrey space; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/2049016.pdf Link otwiera się w nowym oknie
Opis:: In this paper we define a new class of continuous fractional wavelet transform (CFrWT) and study its properties in Hardy space and Morrey space. The theory developed generalize and complement some of already existing results.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Identification of sonar detection signal based on fractional Fourier transform
Autorzy:: Wang, B.
Tang, J.
Yu, F.
Zhu, Z.
Tematy:: fractional Fourier transform
watermark
sonar; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/259724.pdf Link otwiera się w nowym oknie
Opis:: Aiming at the source of underwater acoustic emission, in order to identify the enemy emission sonar source accurately. Using the digital watermarking technology and combining with the good time-frequency characteristics of fractional Fourier transform (FRFT),this paper proposes a sonar watermarking method based on fractional Fourier transform. The digital watermark embedding in the fractional Fourier transform domain and combined with the coefficient properties of the sonar signal in the fractional Fourier transform to select the appropriate watermark position. Using the different characteristics of the signals before and after embedding, an adaptive threshold was set for the watermark detection to realize the discrimination of sonar signals. The simulation results show the feasibility and has better resolution and large watermark capacity of this method, while the robustness of the watermark is better, and the detection precision is further improved.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Image encryption algorithm by using the logistic map and discrete fractional angular transform
Autorzy:: Yu, J.
Li, Y.
Xie, X.
Zhou, N.
Zhou, Z.
Tematy:: image encryption
logistic map
discrete fractional angular transform; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/173813.pdf Link otwiera się w nowym oknie
Opis:: A new image encryption scheme based on logistic map and discrete fractional angular transform has been proposed. In the proposed scheme, the original image is encrypted with the random sequence generated by the logistic map, and the encrypted image is subsequently processed by the discrete fractional angular transform, which produces the ciphertext after double encryptions. The parameters of the logistic map and the order of the discrete fractional angular transform serve as the main keys of the image encryption algorithm. Simulation results show that the proposed image encryption algorithm can effectively resist the attacks of statistical analysis, and has acceptable encryption effect and security.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 5.

Tytuł:: Comparative analysis of variants of Gabor-Wigner Transform for crossterm reduction
Autorzy:: Ajab, M.
Taj, I. A.
Khan, N. A.
Tematy:: Wigner Distribution
Gabor transform
Gabor Wigner Transform
fractional Fourier transform; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/221743.pdf Link otwiera się w nowym oknie
Opis:: Gabor Wigner Transform (GWT) is a composition of two time-frequency planes (Gabor Transform (GT) and Wigner Distribution (WD)), and hence GWT takes the advantages of both transforms (high resolution of WD and cross-terms free GT). In multi-component signal analysis where GWT fails to extract auto-components, the marriage of signal processing and image processing techniques proved their potential to extract autocomponents. The proposed algorithm maintained the resolution of auto-components. This work also shows that the Fractional Fourier Transform (FRFT) domain is a powerful tool for signal analysis. Performance analysis of modified fractional GWT reveals that it provides a solution of cross-terms of WD and blurring of GT.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Image encryption combining discrete fractional angular transform with Arnold transform in image bit planes
Autorzy:: Zhou, Z.
Yu, J.
Liao, Q.
Gong, L.
Tematy:: Arnold transform
bit plane
discrete fractional angular transform
image encryption algorithm; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/173704.pdf Link otwiera się w nowym oknie
Opis:: A new image encryption algorithm by using a discrete fractional angular transform and Arnold transform in image bit planes is investigated. In the image encryption algorithm, the original image is encrypted by the Arnold transform in image bit planes firstly, and then the resulting image is encrypted by the discrete fractional angular transform further. The key of the image encryption algorithm includes the parameters of the Arnold transform and the order of the discrete fractional angular transform. It is shown that the proposed image encryption algorithm is of high security and strong enough to counteract some conventional image attack manners.
Dostawca treści:: Biblioteka Nauki

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na półce

Skocz do pozycji: 7.

Tytuł:: High-security image encryption by multiplexing phase encoding in domains of dual optical transforms
Autorzy:: Li, Zhihui
Gao, Bin
Pan, Xiaoou
Li, Linlin
Wang, Chenxuan
Zuo, Weizhuo
Ji, Yu
Liu, Shutian
Liu, Zhengjun
Tematy:: extended fractional Fourier transform
geometric operations
random phase encoding; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/27310099.pdf Link otwiera się w nowym oknie
Opis:: A novel optical image encryption is proposed based on multiplexing of the random phase encoding with shift and rotation operations in domains of two transforms, extended fractional Fourier transform (eFrFT) and Fresnel transform. The original image is subjected to eFrFT with the action of the random phase mask. The mask is shifted and rotated to enhance the security of this encryption method. The image obtained from eFrFT is entered into Fresnel diffraction by the use of the phase mask to obtain the final encrypted image. We plan for the phase keys to be multiplexed in order to decrease the amount of keys that need to be stored in an application. Here, the displacement, rotation angle, and wavelength in this system can be used as additional keys to improve the security and reliability of the encryption system. Numerical experiments are conducted to verify the effectiveness and security of the method. The findings demonstrate that the keys are sufficiently sensitive for high security.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Construction of waveform library in cognitive radar
Autorzy:: Guo, Y.
Wu, Y.
Liu, H.
Tematy:: fractional Fourier transform
ambiguity function
Barker
Frank
waveform libraries; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/260610.pdf Link otwiera się w nowym oknie
Opis:: Based on the thoughts of cognitive radar, Fractional Fourier Transform (FrFT) is used to generate a rotatable waveform libraries of Frank coded/Barker coded waveform in this paper. Then, the ambiguity function is used to analyze the delay resolution, Doppler resolution, delay side-lobe level, and Doppler side-lobe level of the waveform libraries and orthogonality of them is also analyzed. Furthermore, we proved theoretically that there is a fixed coordinate transformation between the waveforms of library and its origin waveform. Therefore, the Cramér-Rao low bound (CRLB) of motion parameters can be computed easily using the waveforms of the libraries, which facilitate the subsequent waveform scheduled work. Simulation results show that the library waveforms can reduce delay resolution to satisfy the different situations and can bring significant benefits for delay resolution, orthogonality and reuse interval.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Color image encryption using affine transform in fractional Hartley domain
Autorzy:: Singh, P.
Yadav, A. K.
Singh, K.
Tematy:: color image encryption
affine transform
fractional Hartley transform
occlusion and noise attacks; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/173825.pdf Link otwiera się w nowym oknie
Opis:: A novel scheme for color image encryption using the fractional Hartley and affine transforms is proposed. An input color image is first decomposed in its RGB (red, green and blue) components. Each component is bonded with a random phase mask and then subjected to a fractional Hartley transform followed by affine transform. Thereafter, a second random phase mask is applied to each component before the final transformation by fractional Hartley transform resulting in a component-wise encrypted image. Finally, all three components are combined to give a single channel encrypted image. The scheme is validated with numerical simulations performed on a color image of size 256 × 256 × 3 pixels using MATLAB 7.14. The use of affine transform along with fractional Hartley transform adds to the security. The scheme is evaluated for its sensitivity to the parameters of the fractional Hartley and affine transforms. On analysing the plots of correlation coefficient and mean-squared-error, the scheme is found to be highly sensitive to the encryption parameters. Also, it is evaluated for its robustness against the usual noise and occlusion attacks. The proposed scheme is secure and robust owing to multiplicity of encryption parameters introduced through the type of transforms used.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Asymmetric double-image encryption using twin decomposition in fractional Hartley domain
Autorzy:: Kumar, Jaideep
Singh, Phool
Yadav, Ak
Tematy:: double image encryption
twin decomposition
asymmetric cryptosystem
fractional Hartley transform; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/2060684.pdf Link otwiera się w nowym oknie
Opis:: Twin decomposition, consisting of equal and random modulus decompositions, not only makes a cryptosystem asymmetric but also resists special attack. A new double-image asymmetric crypto-system using twin decomposition in fractional Hartley domain is proposed. An input grayscale image, bonded with another grayscale image as its phase mask, is transformed via fractional Hartley transform. Equal modulus decomposition is applied on the resulting image, giving us two intermediate images. One of them is subjected to another fractional Hartley transform followed by random modulus decomposition, whereas the other serves as the first private key. The application of random modulus decomposition also results in two images: encrypted image and the second private key. During the process of decryption, firstly the encrypted image is combined with second private key and thereafter it is subjected to inverse fractional Hartley transform. The resulting image is then combined with the first private key, and followed by another inverse fractional Hartley transform, thus recovering the two original images. The proposed cryptosystem is validated for pairs of grayscale images.
Dostawca treści:: Biblioteka Nauki

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