Search results for "kohina"
showing 6 items of 6 documents
On GPU-accelerated fast direct solvers and their applications in image denoising
2015
Fabrication, Electrical Characterization and 1/f Noise Study of Submicron-sized Superconducting Tunnel Junctions
2016
Studies of transition-edge sensor physics : thermal models and noise
2011
This thesis focuses on studying the noise in transition-edge sensors (TES). More specifically, the aim is to find an explanation for the observed excess noise that is limiting their performance and has been troubling the TES field in recent years. Several theories have been put forth but a definitive answer is still missing. In the early stages of this thesis work a novel theory was presented for the noise in a special TES geometry. In our theory the excess noise is caused by correlated fluctuations of superconductivity at the phase boundary between normal and superconducting states. Data from more recent experiments does not give solid support for the theory and in this thesis the validity…
Optimization-based techniques for image restoration
2001
Kohinanpoisto on olennainen osa kuvankäsittelyä. FL Kirsi Majavan väitöskehittää uuden menetelmän, jolla paljon häiriötä sisältävästä kuvasta löytyvät sekä jyrkät rajat että sileät osat. Ne ovat perinteisen kuvankäsittelyn ongelma-alueita. Työssä kehitetään myös uusia, tehokkaita numeerisia ratkaisumenetelmiä erilaisille kohinanpoistotehtäville. Jos kuvia halutaan analysoida automaattisesti tietokoneella, on usein välttämätöntä aloittaa kuvankäsittely poistamalla kuvasta kohinaa ja muita vääristymiä. Jos kuvasta halutaan automaattisesti löytää ja tunnistaa siinä esiintyvät objektit, on lisäksi olennaista, että kohinanpoisto säilyttää mahdollisimman tarkasti objektien reunat. Usein kuvankäsi…
Analysis of microtomographic images of porous heterogeneous materials
2015
In this work, we study the phases of image processing chain of microtomographic imag- ing in order to obtain reliable results while optimizing the time spent on denoising and segmentation. We consider that the decisions made at the early phases of the processing chain are most important and the selection made there essentially determine the overall quality of imaging process. We also compare here various denoising method qualita- tively, however, we think that the pure noise removal ability is not the only requirement for noise removal in microtomographic images. By proper denoising we can affect selec- tion of segmentation methods and, thus, also the quality of the analysis. Additionally, …
IEEE Access Special Section Editorial: Exploiting the Benefits of Interference in Wireless Networks: Energy Harvesting and Security
2018
Interference used to be viewed as a harmful factor in wireless networks, which can reduce the quality of information transmission. To combat against interference, many interference management techniques have emerged. Due to the latest research advances, interference (or noise) can also be exploited to offer some benefits to wireless networks. The first aspect is that interference in multi-user networks can be collected as a green power supply for the transceivers, known as wireless energy harvesting. Another application is that one can generate artificial noise to disrupt the adversarial eavesdropping, and guarantee the security of wireless networks. Therefore, conventional interference man…