The problem of road sign detection and recognition is very important in many practical problems, above all for road cadastral authorities. In this sense, an automatic application able to identify the kind of a road sign starting from common imageries such as photos could be very helpful. The main difficulty is due to a possible poor graphical definition of the imagery. In this case, a valid sup...

A CBIR system for retrieving images with specific buildings from databases is proposed in this paper. We exploit the parallelism invariance property of the line features of buildings in images in the derivation of two new geometrically invariant linear feature descriptors. We call these descriptors Hough descriptors as they are extracted from the Hough transform domain. The underlying concept i...

Automatic pupil detection is often required as a necessary function in modern Ophthalmology diagnosis. After analyzing the major challenges existing in various diagnosis environments, this paper suggests a stepwise work–flow combining machine vision algorithms including spatial convolution, circular Hough transform and region growing, to provide robust and precision alignment between diagnostic...

At the center of the macula, fovea plays an important role in computer-aided diagnosis. To locate the fovea, this paper proposes a vessel origin (VO)-based parabolic model, which takes the VO as the vertex of the parabola-like vasculature. Image processing steps are applied to accurately locate the fovea on retinal images. Firstly, morphological gradient and the circular Hough transform are use...

v LIST OF TABLES vi LIST OF FIGURES viii CHAPTER 1. nslTRODUCTION 1 1.1 Motivation and Problem Statement 1 1.2 Previous Research 4 1.3 Thesis Organization 5 2. MATHEMATICAL METHODS FOR PREPROCESSING AND IMPLEMENTATION WITH THE CUSTOMIZED HOUGH TRANSFORM 7 2.

A new branch of Hough Transform algorithms, called probabilistic Hough Transforms, has been actively developed in recent years. One of the rst was a new and eecient probabilistic version of the Hough Transform for curve detection, the Randomized Hough Transform (RHT). The RHT picks n pixels from an edge image by random sampling to solve n parameters of a curve and then accumulates only one cell...

Replacing the Hough calculation of the trigonomeric functions, sine and cos0,by the piece-wise linear Hough function(PLH), the basic cost for the sine , cose and the multiplications is removed. The PLH function is directly introduced from the usual Hough function. The PLH function inherits the basic properties of the usual Hough function from the view point to extract the line patterns from the...

The Discriminative Generalized Hough Transform (DGHT) is a method for object localization, which combines the standard Generalized Hough Transform (GHT) with a discriminative training technique. In this setup the aim of the discriminative training is to equip the models used in the GHT with individual model point weights such that the localization error in the GHT becomes minimal. In this paper...

This paper studies the use of the generalised Hough transform to locate objects possessing concavities. Hhen locating objects with internal symmetries, ambiguities can arise which nay not be resolvable in the presence of occlusions. On the other hand concavities can help to lake object location more accurate. The boundary orientation distribution can be used to analyse the situation: it shows t...