Discrete sine transform

About: Discrete sine transform is a research topic. Over the lifetime, 3269 publications have been published within this topic receiving 73181 citations.

The discrete fractional Fourier transform and Harper's equation

Abstract: It is shown that the discrete fractional Fourier transform recovers the continuum fractional Fourier transform via a limiting process whereby inner products are preserved.

Multiplyless discrete cosine transform

Abstract: A method is disclosed for performing a discrete cosine transform on a transform input value wherein the discrete cosine transform has a plurality of predetermined transform coefficients. A number N 1 of shift operations is determined independently of the transform input value in order to provide a set of N 1 of shift operations. A number N 2 of add operations is determined independently of the transform input value in order to provide a set of N 2 add operations. The transform input value is operated upon only by the N 1 shift operations and the N 2 add operations to provide a discrete cosine transform output value without any multiplication. This method may be applied to both forward and inverse discrete cosine transforms. The transform coefficients are simplified coefficients which are provided by truncating and modifying prior art transform coefficients. This simplification is adapted to provide coefficients which require fewer than a predetermined number of shift and add operations in order to determine an approximation of the product which would result from a multiplication by the coefficient. The simplification of the coefficients causes degradation of a video image transformed using the simplified coefficients. Therefore the simplification is constrained to cause an acceptable amount of image degradation.

Digital Image Watermarking Technique Using Discrete Wavelet Transform and Discrete Cosine Transform

Abstract: Digital watermarking has been proposed as a viable solution to the need of copyright protection and authentication of multimedia data in a networked environment, since it makes possible to identify the author, owner, distributor or authorized consumer of a document. In this paper a new watermarking technique to add a code to digital images is presented: the method operates in the frequency domain embedding a pseudo-random sequence of real numbers in a selected set of DCT coefficient. And a new method for digital image watermarking which does not require the original image for watermark detection. The watermark is added in select coefficients with significant image energy in the transform domain in order to ensure non- erasability of the watermark. Advantages of the proposed method include: improved resistance to attacks on the watermark, implicit visual masking utilizing the time-frequency localization property of wavelet transform and a robust definition for the threshold which validates the watermark.. Experimental results demonstrate that this proposed technique is robust to most of the signal processing techniques and geometric distortions.

A new transform for 2-D signal representation (MRT) and some of its properties

Abstract: A new transform (MRT) for two-dimensional signal representation and some of its properties are proposed in this paper. The transform helps to do the frequency domain analysis of two-dimensional signals without any complex operations but in terms of real additions. It is obtained by exploiting the periodicity and symmetry of the exponential term in the discrete Fourier transform (DFT) relation, and by grouping related data. Forward and inverse relations of the transform are presented. The transform coefficients show useful redundancies among themselves. These redundancies, which can be used to implement the transform, are studied. A few properties of the transform are studied and the relevant relations are presented.