Search results for "InGaN"

Distance-based relevance feedback using a hybrid interactive genetic algorithm for image retrieval

2011

Content-based image retrieval (CBIR) systems aim to provide a means to find pictures in large repositories without using any other information except the own content of the images, which is usually represented as a feature vector extracted from low-level descriptors. This paper describes a CBIR algorithm which combines relevance feedback, evolutionary computation concepts and distance-based learning in an attempt to reduce the existing gap between the high level semantic content of the images and the information provided by their low-level descriptors. In particular, a framework which is independent from the particular features used is presented. The effect of different crossover strategies…

Innovative modelling techniques in computer vision

1996

Abstract The paper is concerned with two of main research activities currently carried on at the Computer Science and Artificial Intelligence lab of DIE. The first part deals with hybrid artificial vision models, intended to provide object recognition and classification capabilities to an autonomous intelligen system. In this framework, a system recovering 3-D shape information from grey-level images of a scene, building a geometric representation of the scene in terms of superquadrics at the geometric level, and reasoning about the scene at the symbolic level is described. In the second part, attention is focused on automatic indexing of image databases. JACOB, a prototypal system allowing…

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…

Energy Efficient Optimization for Solar-Powered UAV Communications System

2021

In this work, we explore the energy efficiency optimization for a solar-powered unmanned aerial vehicle (UAV) communications system. We consider a scenario where a number of ground users (GUs) connect with a solar-powered multi-antenna UAV over a wireless link. First, we are able to derive the relations between the uplink data rate and heading angle of UAV and transmission power of GUs. In addition, the harvested energy from solar light is also affected by UAV’s angle. Accordingly, with the objective to maximize the energy efficiency that is related to uplink data rate and energy consumption, we propose to dynamically adjust the UAV trajectory and gesture, by optimizing its velocity, accele…

Energy consumption and optimal relay node placement for cooperative retransmissions

2010

Previous work on cooperative MAC design has shown significant performance improvement in terms of throughput and packet delivery ratio. However, little attention has been paid to extra energy cost at the relay node in order to achieve such benefit. In this paper, we focus on analyzing energy consumption at a relay node in cooperative retransmission networks with mixed Rayleigh and Rician fading channels. Furthermore, optimal relay location is studied with respect to energy efficiency in different scenarios. The simulation and calculation results coincide with each other, both showing the optimal location of the relay node is scenario-dependent and can be obtained under given channel conditi…

An optimal energy efficient cooperative retransmission MAC scheme in wireless networks

2011

While the benefits of cooperative diversity have been well studied in the literature, cooperative MAC protocol design has also attracted much attention recently. In the single-relay Cooperative Automatic Repeat reQuest (C-ARQ) protocol, the best relay node is selected in a distributed manner by relays using different backoff time before packet retransmission. However, this relay selection scheme does not work efficiently in a dense network scenario, due to possible high collision probability among different contending relays. In this paper, we propose an optimized relay selection scheme to maximize system energy efficiency by reducing collision probability. The energy efficiency performance…

2020

Abstract. Despite the availability of both commercial and open-source software, an ideal tool for digital rock physics analysis for accurate automatic image analysis at ambient computational performance is difficult to pinpoint. More often, image segmentation is driven manually, where the performance remains limited to two phases. Discrepancies due to artefacts cause inaccuracies in image analysis. To overcome these problems, we have developed CobWeb 1.0, which is automated and explicitly tailored for accurate greyscale (multiphase) image segmentation using unsupervised and supervised machine learning techniques. In this study, we demonstrate image segmentation using unsupervised machine le…

Motion estimation and reconstruction of piecewise planar scenes from two views

2010

The task of recovering the camera motion relative to the environment (motion estimation) is fundamental to many computer vision applications. We present an algorithm for reconstruction of piece-wise planar scenes from only two views and based on minimum line correspondences. We first recover camera rotation by matching vanishing points based on the methods already exist in the literature and then recover the camera translation by searching among a family of hypothesized planes passing through one line. Unlike algorithms based on line segments, the presented algorithm does not require an overlap between two line segments or more than one line correspondence across more than two views to reco…

The iterative object symmetry transform

2005

This paper introduces a new operator named the Iterated Object Transform that is computed by combining the Object Symmetry Transform with the morphological operator erosion. This new operator has been applied on both binary and gray levels images showing the ability to grasp the internal structure of a digital object. We present some experiments on real images in face analysis.

Saliency Based Aesthetic Cut of Digital Images

2013

Aesthetic cut of photos is a process well known to professional photographers. It consists of cutting the original photo to remove less relevant parts close to the borders leaving in this way the interesting subjects in a position that is perceived by the observer as more pleasant. In this paper we propose a saliency based technique to automatically perform aesthetic cut in images. We use a standard method to estimate the saliency map and propose some post processing on the map to make it more suitable for our scope. We then apply a greedy algorithm to determine the cut (i.e. the most important part of the original image) both in the cases of free and fixed aspect ratio. Experimental result…