Based on the discrete fractional random transform (DFRNT), we present the discrete fractional random cosine and sine transforms (DFRNCT and DFRNST). We demonstrate that the DFRNCT and DFRNST can be regarded as special kinds of DFRNT and thus their mathematical properties are inherited from the DFRNT. Numeral results of DFRNCT and DFRNST for one and two dimensional functions have been given.

In the paper, a family of methods that work in the domain of Discrete Fourier and Discrete cosine transforms and proved to be very efficient for adaptive and local adaptive image restoration and target location is reviewed and possible ways for their implementation in analog optical image processors that work with the speed of light are discussed. ©Anita Publications reserved. All rights reserved.

-The discrete Legendre transform is compared to the discrete cosine transform (DCT), which is based on Chebyshev polynomials, in terms of image compression efficiency. Using standard test images in various image compression configurations, the DCT is found to perform marginally better than the discrete Legendre transform in all cases examined. A simplified fundamental matrix theory for construc...

In this paper a reversible discrete cosine transform (RDCT) is presented. N-point reversible transform is firstly presented, then 8-point RDCT is obtained by substituting the 2 and 4point reversible transforms for 2 and 4-point transforms which compose 8-point discrete cosine transform (DCT), respectively. Integer input signal can be losslessly recovered, although the transform coefficients are...

In many signal processing applications, recent techniques often rely on the estimation of a probabilistic model. Many times, this model does not focus on the observed data itself, but rather on a spectral or time-frequency transform of this data, such as the discrete Fourier transform (DFT) or the short-time Fourier transform (STFT). A common statistical assumption regarding these transforms is...

The finger knuckle print (FKP) of a particular person is found to be unique and can serve as a biometric feature has been revealed recently by the researchers. In this paper finger knuckle print will be used as a biometric feature. The databaseImages from Hong KongPolytechnic Universitywere processed using Kekre’s hybrid wavelet type 1 and type 2 for the generation of results. Kekre’s hybrid wa...

A fast algorithm for computing the two-dimensional (2-D) forward and inverse modified discrete cosine transform (MDCT and IMDCT) is proposed. The algorithm converts the 2-D MDCT and IMDCT with block size M×N into four 2-D discrete cosine transforms (DCTs) with block size (M/4)×(N/4). It is based on an algorithm recently presented by Cho [7] for the efficient calculation of one-dimensional MDCT ...

In this paper, we report a novel heuristic for requantizing JPEG images. The resulting images are generally smaller and often have improved perceptual image quality over a "blind" requantization approach, that is, one that does not consider the properties of the quantization matrices. The heuristic is supported by a detailed mathematical treatment which incorporates the well-known Laplacian dis...

For signal representation, it is always preferred that a signal be represented using a minimum number of parameters. In any transform coding scheme, the central operation is the reduction of correlation and thereby, with appropriate coding of the transform coefficients, allows data compression to be achieved. The objective of data encoding is to transform a data array into a statistically uncor...

Current research in image compression (wavelets, local trigono-metric bases, JPEG, etc.) centres on adaptive coding of the grey levels of the image. These methods may be described as using band-limiting procedures with a band-limit that depends on the local properties of the image. This paper looks at the non-adaptive use of Discrete Cosine Transforms in blocks, with uniform band-limits over th...