On computation of Hough functions

On computation of Hough functions

Hough functions are the eigenfunctions of the Laplace tidal equation governing fluid motion on a rotating sphere with a resting basic state. Several numerical methods have been used in the past. In this paper, we compare two of those methods: normalized associated Legendre polynomial expansion and Chebyshev collocation. Both methods are not widely used, but both have some advantages over the co...

study of hash functions based on chaotic maps

توابع درهم نقش بسیار مهم در سیستم های رمزنگاری و پروتکل های امنیتی دارند. در سیستم های رمزنگاری برای دستیابی به احراز درستی و اصالت داده دو روش مورد استفاده قرار می گیرند که عبارتند از توابع رمزنگاری کلیددار و توابع درهم ساز. توابع درهم ساز، توابعی هستند که هر متن با طول دلخواه را به دنباله ای با طول ثابت تبدیل می کنند. از جمله پرکاربردترین و معروف ترین توابع درهم می توان توابع درهم ساز md4, md...

Fast 3D Hough Transform Computation

We present a three-dimensional generalization of linear Hough transform allowing fast calculating of sums along all planes in discretized space. The main idea of this method is multiple calculation of two-dimensional fast Hough transforms combined with a specific method for plane parametrization. Compared to the direct summation, the method achieves significant acceleration ( O(n log n) vs O(n)...

Ensemble computation approach to the Hough transform

It is demonstrated that the classical Hough transform with shift-elevation parametrization of digital straight lines has additive complexity of at most O(n3/ logn) on a n× n image. The proof is constructive and uses ensemble computation approach to build summation circuits. The proposed method has similarities with the fast Hough transform (FHT) and may be considered a form of the “divide and c...

On the Minimum Computation Time of Functions