Search results for " Segmentation"

A fully automatic method for biological target volume segmentation of brain metastases

2016

Leksell Gamma Knife is a mini-invasive technique to obtain a complete destruction of cerebral lesions delivering a single high dose radiation beam. Positron Emission Tomography (PET) imaging is increasingly utilized for radiation treatment planning. Nevertheless, lesion volume delineation in PET datasets is challenging because of the low spatial resolution and high noise level of PET images. Nowadays, the biological target volume (BTV) is manually contoured on PET studies. This procedure is time expensive and operator-dependent. In this article, a fully automatic algorithm for the BTV delineation based on random walks (RW) on graphs is proposed. The results are compared with the outcomes of…

AUTOMATIC RETINA EXUDATES SEGMENTATION WITHOUT A MANUALLY LABELLED TRAINING SET

2011

International audience; Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, two new methods for the detection of exudates are presented. The methods do not require a lesion training set so the need to ground-truth data is avoided with significant time savings and independence from human error. We evaluate our algorithm with a new publicly available dataset from various ethnic groups and levels of DME. Also, we compare our results with two recent exudate segmentation algorithms on the same dataset. In all of …

Segmentation boundaries in accelerometer data of arm motion induced by music : online computation and perceptual assessment

2022

Segmentation is a cognitive process involved in the understanding of information perceived through the senses. Likewise, the automatic segmentation of data captured by sensors may be used for the identification of patterns. This study is concerned with the segmentation of dancing motion captured by accelerometry and its possible applications, such as pattern learning and recognition, or gestural control of devices. To that effect, an automatic segmentation system was formulated and tested. Two participants were asked to ‘dance with one arm’ while their motion was measured by an accelerometer. The performances were recorded on video, and manually segmented by six annotators later. The annota…

Zero-shot Semantic Segmentation using Relation Network

2021

Zero-shot learning (ZSL) is widely studied in recent years to solve the problem of lacking annotations. Currently, most studies on ZSL are for image classification and object detection. But, zero-shot semantic segmentation, pixel level classification, is still at its early stage. Therefore, this work proposes to extend a zero-shot image classification model, Relation Network (RN), to semantic segmentation tasks. We modified the structure of RN based on other state-of-the-arts semantic segmentation models (i.e. U-Net and DeepLab) and utilizes word embeddings from Caltech-UCSD Birds 200-2011 attributes and natural language processing models (i.e. word2vec and fastText). Because meta-learning …

WATCHING PEOPLE: ALGORITHMS TO STUDY HUMAN MOTION AND ACTIVITIES

2020

Nowadays human motion analysis is one of the most active research topics in Computer Vision and it is receiving an increasing attention from both the industrial and scientific communities. The growing interest in human motion analysis is motivated by the increasing number of promising applications, ranging from surveillance, human–computer interaction, virtual reality to healthcare, sports, computer games and video conferencing, just to name a few. The aim of this thesis is to give an overview of the various tasks involved in visual motion analysis of the human body and to present the issues and possible solutions related to it. In this thesis, visual motion analysis is categorized into thr…

Space-Frequency Quantization for Image Compression With Directionlets

2007

The standard separable 2-D wavelet transform (WT) has recently achieved a great success in image processing because it provides a sparse representation of smooth images. However, it fails to efficiently capture 1-D discontinuities, like edges or contours. These features, being elongated and characterized by geometrical regularity along different directions, intersect and generate many large magnitude wavelet coefficients. Since contours are very important elements in the visual perception of images, to provide a good visual quality of compressed images, it is fundamental to preserve good reconstruction of these directional features. In our previous work, we proposed a construction of critic…

Segmentation of Employee Perceptions in Relation to Corporate Social Responsibility Practices

2013

Sustainability is changing the competitive landscape and reshaping the opportunities and threats that companies face. However, for companies to become green they need employees to develop, believe and engage with these initiatives. To achieve success with sustainable practices, companies can use internal marketing which is based on the satisfaction of employees as a premise to achieve the retention and attraction of top talent that will lead to corporate success. It is estimated that the internal customer satisfaction and loyalty contribute to satisfying the external customers, leading ultimately to a company's profit maximization. In this paper I explore the impact of companies' sustainabi…

Gestión empresarial y dinámica laboral en España

2015

El objetivo del presente artículo es plantear una serie de reflexiones sobre la dinámica labo- ral reciente en la economía española bajo el enfoque analítico de la segmentación laboral. Desde esta perspectiva, la situación y problemas del mercado laboral se explican por un conjunto de factores relacionados con las prácticas de gestión empresarial y no tanto por la regulación que limita la competencia en el mercado o las modalidades contractuales. Nues- tra conclusión es que es necesario superar el marco analítico restringido del enfoque econó- mico convencional e introducir otras dimensiones, que van más allá del mercado, para una mejor compresión de los problemas laborales. En este sentido…

The Analysis of Consumer Behavior in Relationship to a Global Brand in the Lodging Industry, Across Europe and North America Abstract: The world is c…

2011

Market Segmentation in the Decision Making Process in Tourism

2014

In this paper, I examine the responses of 154 tourists in relation to their predisposition to purchase and the patterns and habits that are usually decisive in the decision making process regarding tourism services or products. For this research, I conducted a selective direct research, whose purpose was to obtain a segmentation of consumers who purchase tourism services based on specific dimensions of behavior. This research also implied studying the behavior of current and potential customers who purchase travel services depending on several variables for establishing different consumption habits. Thus, to establish a more detailed image of the tourists who participated in this direct and…