Search results for "Hough transform"
showing 7 items of 17 documents
Automatic Detection and Characterization of Acoustic Plane-Wave Reflections Using Circular Microphone Arrays
2013
The spatial characteristics of the sound field inside a room can be meaningfully described by means of microphone array processing techniques. In this context, the set of impulse responses sampled by a microphone array can be seen as an image made of acoustic plane-wave footprints. Due to the circular geometry of the microphone array, these footprints have a cosine-like shape that can be fully described as a function of the direction of arrival (DOA) of the impinging plane wave. This paper proposes a Hough-transform-based approach to plane-wave detection in microphone array multi-trace impulse responses. Experiments using a set of real microphone recordings are described, showing the potent…
Automated Detection of Optic Disc Location in Retinal Images
2008
This contribution presents an automated method to locate the optic disc in color fundus images. The method uses texture descriptors and a regression based method in order to determine the best circle that fits the optic disc. The best circle is chosen from a set of circles determined with an innovative method, not using the Hough transform as past approaches. An evaluation of the proposed method has been done using a database of 40 images. On this data set, our method achieved 95% success rate for the localization of the optic disc and 70% success rate for the identification of the optic disc contour (as a circle).
Event reconstruction methods for the HypHI Phase 0 experiment at GSI
2010
WOS: 000282530300034
Optimizing Hough transform for fertilizer spreading optical control
2006
International audience; In Europe, centrifugal spreading is a widely used method for agricultural soil fertilization. In this broadcasting method, fertilizer particles fall onto a spinning disk, are accelerated by a vane, and afterward are ejected into the field. To predict and control the spread pattern, a low-cost, embeddable technology adapted to farm implements must be developed. We focus on obtaining the velocity and the direction of fertilizer granules when they begin their flight by means of a simple imaging system. We first show that the outlet angle of the vane is a bounded value and that its measurement provides the outlet velocity of the particle. Consequently, a simple camera un…
Randomized Hough Transform for Ellipse Detection with Result Clustering
2005
Our research is focused on the development of robust machine vision algorithms for pattern recognition. We want to provide robotic systems the ability to understand more on the external real world. In this paper, we describe a method for detecting ellipses in real world images using the randomized Hough transform with result clustering. A preprocessing phase is used in which real world images are transformed - noise reduction, greyscale transform, edge detection and final binarization - in order to be processed by the actual ellipse detector. The ellipse detector filters out false ellipses that may interfere with the final results. Due to the fact that usually more "virtual" ellipses are de…
Detection of rupture lines for active scanning
2007
Corner and junction detection is an important preprocessing step in image registration, data fusion, object recognition, and many other tasks. This work deals with corner and junction detection of characteristic features of the structure resulting from cross-pattern projection. The ultimate aim is to adapt the positions and orientation of the cross-pattern projections to what has been observed. The use of this projected light pattern in the framework of active vision allows us to identify certain points of interest on 3-D objects, to directly acquire a synthesis, which thus permits simplified detection, measurement, recognition, or tracking. We present detection methods for corners and junc…
Automatic Conjunctival Provocation Test Using Hough Transform of Extended Canny Edge Maps
2013
Computer-aided diagnosis is developed for assessment of allergic rhinitis/rhinoconjunctivitis measuring the relative redness of sclera under application of allergen solution. The patient’s eye images are taken from commercial digital camera. The iris is robustly localized using a gradient-based Hough circle transform. From the center of the pupil, the region of interest within the sclera is extracted using geometric anatomybased a-priori information. The red color pixels are extracted thresholding in the hue, saturation and value color space. Then, redness is measured by taking mean of saturation projected into zero hue. Evaluation is performed with 92 images taken from 13 subjects, 8 respo…