Search results for "Image"
showing 10 items of 6818 documents
A new algorithm for bit rate allocation in JPEG2000 tile encoding
2004
A new algorithm for allocating a given bit rate to different image tiles in the JPEG2000 encoding system is proposed. The algorithm outperforms other approaches commonly used in implementations. The new algorithm is suitable when information content is not equally distributed across the image. It is based on the computation of an index of the information content of each tile. To implement the proposed approach, we modified JasPer, a free software-based JPEG2000 coder implementation (Adams, M.D. and Kossentini, F., Proc. IEEE Int. Conf. on Image Process., vol.2, p.53-6, 2000). The experimentation was carried out on a subset of the JPEG2000 test images. Experimental results are reported, show…
Restoration of out of focus images based on circle of confusion estimates
2002
In this paper a new method for a fast out-of-focus blur estimation and restoration is proposed. It is suitable for CFA (Color Filter Array) images acquired by typical CCD/CMOS sensor. The method is based on the analysis of a single image and consists of two steps: 1) out-of-focus blur estimation via Bayer pattern analysis; 2) image restoration. Blur estimation is based on a block-wise edge detection technique. This edge detection is carried out on the green pixels of the CFA sensor image also called Bayer pattern. Once the blur level has been estimated the image is restored through the application of a new inverse filtering technique. This algorithm gives sharp images reducing ringing and c…
Automatic Volumetric Liver Segmentation Using Texture Based Region Growing
2010
In this paper an automatic texture based volumetric region growing method for liver segmentation is proposed. 3D seeded region growing is based on texture features with the automatic selection of the seed voxel inside the liver organ and the automatic threshold value computation for the region growing stop condition. Co-occurrence 3D texture features are extracted from CT abdominal volumes and the seeded region growing algorithm is based on statistics in the features space. Each CT volume is composed by 230 slices, having 512 x 512 pixels as spatial resolution, and 12-bit gray level resolution. In this initial feasible study, 5 healthy volunteer acquisitions has been used. Tests have been p…
A Graph-Based Method for PET Image Segmentation in Radiotherapy Planning: A Pilot Study
2013
Target volume delineation of Positron Emission Tomography (PET) images in radiation treatment planning is challenging because of the low spatial resolution and high noise level in PET data. The aim of this work is the devel- opment of an accurate and fast method for semi-automatic segmentation of me- tabolic regions on PET images. For this purpose, an algorithm for the biological tumor volume delineation based on random walks on graphs has been used. Va- lidation was first performed on phantoms containing spheres and irregular in- serts of different and known volumes, then tumors from a patient with head and neck cancer were segmented to discuss the clinical applicability of this algo- rith…
The four types of self-adaptive systems: A metamodel
2017
The basic ideas of self-adaptive systems are not a novelty in computer science. There are plenty of systems that are able of monitoring their operative context to take run-time decisions. However, more recently a new research discipline is trying to provide a common framework for collecting theory, methods, middlewares, algorithms and tools for engineering such software systems. The aim is to collect and classify existing approaches, coming from many different research areas. The objective of this work is providing a unified metamodel for describing the various categories of adaptation.
Fast Volumetric Reconstruction of Human Body through Superquadrics
2013
This paper describes a technique to reconstruct the volumes of the human body. For this purpose, are introduced mathematical objects able to represent 3d shapes, called super quadrics. These objects are positioned in the space according the captures made by a Microsoft Kinect device and are composed to represent the volumes of the human body. The employment of quaternions provides a relevant speedup for the rotation of the volumes and allows to follow the human movements in real time and reduced computational cost.
Efficient rapid prototyping of image and video processing algorithms
2004
Image and video processing tasks are often confined for real-time execution on large size workstations or expensively custom designed hardware. The current availability of mature reconfigurable hardware, like Field Programmable Gate Arrays (FPGAs), coupled with the usage of hardware programming languages offers a good path for porting such applications on portable devices. This paper explores the rapid prototyping of a real-time road sign recognition system on a FPGA, using an algorithmic-like hardware programming language: the Handel-C language. We investigate the relationship between efficient Handel-C data, structures, constructs and the related high level C data, structures, constructs.…
L’exemplum del Dinomenide Gelone tra memoria civica e storiografica
2015
La storia della Sicilia greca è scandita, nei suoi momenti chiave, dalla persistente presenza dell’immagine del Dinomenide Gelone. Questo lavoro analizza le valenze paradigmatiche assunte dalla sua figura nella memoria civica siracusana e nella produzione storiografica; inoltre ricostruisce le dinamiche politiche che hanno spinto i principali tiranni siracusani (da Dionisio I a Ierone II) a stabilire un confronto con Gelone. Il suo exemplum è utilizzato per legittimare azioni politiche e impegno antipunico; particolare attenzione è posta alla Biblioteca storica di Diodoro Siculo e al ruolo che in essa assume la figura del Dinomenide; in relazione a questi aspetti l’opera dell’Agirinense sem…
L’errore fantastico. La fotografia astratta e l’estetica Glitch
2019
Con l’avvento del computer, dei software informatici e delle loro molteplici applicazioni, la fotografia inizia ad accostare alle rappresentazioni oggettive tutta una serie di sperimentazioni visive che rendono l’immagine scattata qualcos’altro da sé, con rese che di fatto si avvicinano più alla pittura che alla fotografia. Attraverso l’uso del Glitch, dell’imprevisto, tecnicamente dell’errore di sistema, l’immagine di partenza diventa una finestra verso visioni ed espressioni artistiche inimmaginabili. Ne derivano rappresentazioni affascinanti la cui bellezza inevitabilmente stupisce. With the advent of computers, computer software and their multiple applications, photography begins to com…
Schermi. Immagini, corpi, condivisioni
2019
In this book the author investigates the digital image proliferation of our times from an interdisciplinary point of view.