Results 251 to 260 of about 113,946 (294)

LAPLACIAN DCT COEFFICIENT MODELS

International Journal of Wavelets, Multiresolution and Information Processing, 2008
It is well known that the distribution of the discrete cosine transform (DCT) coefficients of most natural images follow a Laplace distribution. In this note, a collection of formulas is derived for the distribution of the actual DCT coefficient. The corresponding estimation procedures are derived by the method of moments and the method of maximum ...
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Randomized redundant DCT

SIGGRAPH Asia 2015 Technical Briefs, 2015
j In this paper, we propose an acceleration method for image denoising with a redundant discrete cosine transform (R-DCT). Image denoising is essential for image processing, and its efficiency is important for graphics applications. R-DCT with a hard-thresholding or shrinkage method can perform denoising while keeping detail textures.
Shu Fujita, Norishige Fukushima, Makoto Kimura, Yutaka Ishibashi   +3 more
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Optimum DCT quantization

[Proceedings] DCC `93: Data Compression Conference, 2002
The paper offers a solution to the problem of determining good quantization tables for use with the discrete cosine transform. Using the methods proposed, the designer of a system can choose a selection of test images and a coefficient weighting scenario, from which a quantization table can be produced, optimized for the choices made.
D.M. Monro, B.G. Sherlock
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Gaussian DCT Coefficient Models

Acta Applicandae Mathematicae, 2008
It is assumed that the discrete cosine transform (DCT) coefficients of most natural images follow a Gaussian distribution. In this theoretical work, the author obtains sixteen compounded distribution models from \[ f(x)=\frac{1}{\sqrt {2\pi}}\int^\infty_0\frac{1}{\sigma}\exp\left(-\frac{y^2}{2\sigma^2}\right)g (\sigma^2)d\sigma^2 \] by taking different
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JPEG DCT Compressiom

Advanced Materials Research, 2013
With the rapid spread of image processing applications and the further development of multimedia technologies, compression standards become more and more important. This paper intends to explain JPEG (Joint Photographic Experts Group) compression, which is currently a worldwide standard for digital image compression, is based on the discrete cosine ...
Hong Li Jia, Qiang Liu
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Two Stage Color Image Steganography Using DCT (TSCIS-DCT)

2013
In frequency domain steganography, use of color images for secret data hiding may prove to be a decisive innovation. The proposed concept uses two color images for hiding a color/gray authenticating message/image. The mathematical technique of Discrete Cosine Transform (DCT) is applied on each block of size 2x2 taken in row major order from three color
Anirban Goswami, Dipankar Pal, Nabin Ghoshal   +2 more
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The discrete cosine transform DCT-4 and DCT-8

Proceedings of the 4th international conference conference on Computer systems and technologies e-Learning - CompSysTech '03, 2003
In paper two types of the discrete cosine (end sine) transforms (DCT/DST) are analyzed on the base of the linear representations of finite groups and geometrical approach. This transforms are useful for multirate systems, adaptive filtering and compression of speech signals and images.
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Systolic CORDIC DCT: an effective method for computing 2d-DCT

Seventh International Symposium on Signal Processing and Its Applications, 2003. Proceedings., 2003
The 2D-DCT is used in image and speech processing for real-time application. In this paper a new hardware method is proposed for computing 2D-DCT. The hardware employs systolic array for doing recursive equation and use a CORDIC algorithm for determining some part of computation. So the method is called systolic CORDlC DCT or SCDCT.
A. Khayatzadeh, H.S. Shahhoseini, M. Naderi   +2 more
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Diskrete Kosinustransformation (DCT)

2015
Die Fouriertransformation und die DFT sind fur die Verarbeitung komplexwertiger Signale ausgelegt und erzeugen immer ein komplexwertiges Spektrum, auch wenn das ursprungliche Signal ausschlieslich reelle Werte aufweist. Der Grund dafur ist, dass weder der reelle noch der imaginare Teil des Spektrums allein ausreicht, um das Signal vollstandig ...
Wilhelm Burger, Mark James Burge
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The Discrete Cosine Transform (DCT)

2009
The Fourier transform and the DFT are designed for processing complex-valued signals, and they always produce a complex-valued spectrum even in the case where the original signal was strictly realvalued. The reason is that neither the real nor the imaginary part of the Fourier spectrum alone is sufficient to represent (i.e., reconstruct) the signal ...
Wilhelm Burger, Mark J. Burge
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