Geometrical limitations on the voting process in the classical Hough transform resulting from that the detected objects are opaque to the applied means of measurement are considered. It is assumed that the measurements are made from one point, like in LIDAR scanning. The detected object is a circle and the two point elementary voting set forming its chord is considered. The first type of condit...

The drawbacks of the standard Hough transform (SHT) are the computational time spending and the large storage requirement. Moreover, the voting method of SHT affects accuracy of detection. In this paper, a new voting method is proposed to reduce the computation and storage requirements of SHT for circle detection. This method improves the efficiency of circle detection by letting each pixel onl...

In this paper we proposes a new method t o detect a slanted ellipse using Hough transform with 5 parameters effectively. The procedure is as follows: First, a pair of arcs are detected as a part of the slanted ellipse using a circle detecting Hough transform with 3 parameters; the central point (xc,yc) and the slanted angle 9 can be obtained. Second, the slanted ellipse is transformed into a no...

We present a novel method for detecting circles on digital images. This transform is called the circlet transform and can be seen as an extension of classical 1D wavelets to 2D; each basic element is a circle convolved by a 1D oscillating function. In comparison with other circle-detector methods, mainly the Hough transform, the circlet transform takes into account the finite frequency aspect o...

We present a two-step algorithm for the recognition of circles. The first step uses a 2D Hough Transform for the detection of the centres of the circles and the second step validates their existence by radius histogramming. The 2D Hough Transform technique makes use of the property that every chord of a circle passes through its centre. We present results of experiments with synthetic data demo...

While automatic detection of point sources in astronomical images has experienced a great degree of success, less effort has been directed towards the detection of extended and low-surface brightness features. At present, existing telescopes still rely on human expertise to reduce the raw data to usable images and then to analyse the images for non-pointlike objects. However, the next generatio...

We present a new method for detecting circles on digital images. This transform is called the circlet transform and can be seen as an extension of classical 1D wavelets in 2D: each basic element is a circle convolved by a 1D wavelet. In comparison with other circle-detector methods, mainly the Hough transform, the circlet transform takes into account the finite frequency aspect of the data: a c...

Presented are the methods proposed by authors to identify and model the optic disc in colour retinal images. The first three our approaches localized the optic disc in two steps: a) in the green component of RGB image the optic disc area is detected based on texture indicators and pixel intensity variance analysis; b) on the segmented area the optic disc edges are extracted and the resulted bou...