this paper presents a new procedure for automatic extraction of the blood vessels and optic disk (od) in fundus fluorescein angiogram (ffa). in order to extract blood vessel centerlines, the algorithm of vessel extraction starts with the analysis of directional images resulting from sub‑bands of fast discrete curvelet transform (fdct) in the similar directions and different scales. for this pur...

This paper through Comparative analysis of This Discrete Polar Complex Exponential Transform approach is improved from traditional Polar Complex Exponential Transform (PCET) and this transform also encompasses the features of orthogonality and rotation invariance. We introduce a new 9×9 circle instead of a unit circle in DPCET to calculate features of image more precision. And various experimen...

For a family of weight functions invariant under a finite reflection group, we show how weighted Lp multiplier theorems for Dunkl transform on the Euclidean space Rd can be transferred from the corresponding results for hharmonic expansions on the unit sphere Sd of Rd+1. The result is then applied to establish a Hörmander type multiplier theorem for the Dunkl transform and to show the convergen...

The contrast enhancement technique used manipulates the DCT coefficients of a JPEG image to improve its quality. It is carried out in the decompression stage so that the compressibility of the image is not affected. Since DCT and its inverse transform IDCT are performed on 8 x 8 blocks of pixels, any image processing algorithm implemented in the transform domain produces flaws known as blocking...

This work presents the combining of 2 methods, which are fast Fourier transform spread (FFT-spread) and 2×2 space time block codes (STBC), to boost the system performance for coherent optical orthogonal frequency division multiplexing (COOFDM) communication systems which is faster than the discrete Fourier transform spread (DFT-spread). The system performances are usually measured by the unit o...

With the start of the widespread use of discrete wavelet transform the need for its efficient implementation is becoming increasingly more important. This work presents a general approach of discrete wavelet transform scheme vectorisation evaluated on an FPGAbased Application-Specific Vector Processor (ASVP). This unit can be classified as SIMD computer in Flynn’s taxonomy. The presented approa...

The Mergelyan and Ahlfors-Beurling estimates for the Cauchy transform give quantitative information on uniform approximation by rational functions with poles off K. We will present an analogous result for an integral transform on the unit sphere in C2 introduced by Henkin, and show how it can be used to study approximation by functions that are locally harmonic with respect to the Kohn Laplacia...

|In this paper, we propose uni ed systolic arrays for computation of the 1-D and 2-D discrete cosine transform/discrete sine transform/discrete Hartley transform (DCT/DST/DHT). By decomposing the transforms into evenand odd-numbered frequency samples, the proposed architecture computes the 1-D DCT/DST/DHT. Compared to the conventional methods the proposed systolic arrays exhibit advantages in t...

Frequency-domain and subband implementations improve the computational efficiency and the convergence rate of adaptive schemes. The well-known multidelay adaptive filter (MDF) belongs to this class of block adaptive structures and is a DFT-based algorithm. In this paper, we develop adaptive structures that are based on the trigonometric transforms DCT and DST and on the discrete Hartley transfo...

A Fast algorithm for the Discrete Hartley Transform (DHT) is presented, which resembles radix-2 fast Fourier Transform (FFT). Although fast DHTs are already known, this new approach bring some light about the deep relationship between fast DHT algorithms and a multiplication-free fast algorithm for the Hadamard Transform. Key-words Discrete transforms, Hartley transform, Hadamard Transform.