Sökresultat

Filtyp

Din sökning på "*" gav 535382 sökträffar

Non-rigid registration of mammograms obtained with variable breast compression : A phantom study

The amount of breast compression applied during a mammographic exam affects the appearance of mammograms by introducing variations in the shape, position, and contrast of breast anatomical structures, which can conceal existing breast abnormalities or generate false alarms. Due to the complex tissue organization and elastic properties of the breast and the projective nature of mammography, rigid r

Aliasing effects in digital images of line-pair phantoms

Line-pair phantoms are commonly used for evaluating screen-film systems. When imaged digitally, aliasing effects give rise to additional periodic patterns. This paper examines one such effect that medical physicists are likely to encounter, and which can be used as an indicator of super-resolution.

Mammogram synthesis using a 3D simulation. I. Breast tissue model and image acquisition simulation

A method is proposed for generating synthetic mammograms based upon simulations of breast tissue and the mammographic imaging process. A computer breast model has been designed with a realistic distribution of large and medium scale tissue structures. Parameters controlling the size and placement of simulated structures (adipose compartments and ducts) provide a method for consistently modeling im

Mammogram synthesis using a 3D simulation. II. Evaluation of synthetic mammogram texture

We have evaluated a method for synthesizing mammograms by comparing the texture of clinical and synthetic mammograms. The synthesis algorithm is based upon simulations of breast tissue and the mammographic imaging process. Mammogram texture was synthesized by projections of simulated adipose tissue compartments. It was hypothesized that the synthetic and clinical texture have similar properties, a

Generation and evaluation of physically inspired synthetic mammograms

A software breast phantom, based upon a breast tissue model derived from physical properties of breast anatomy, has been developed for mammography simulation. Synthetic mammograms, obtained by applying a breast compression model and an x-ray acquisition model to the software breast phantom, were compared by quantitative and qualitative means with real mammograms at different scales. Good agreement

CNN paradigm based multilevel halftoning of digital images

-An algorithm for displaying gray level images using a small number of flxed quantization levels is proposed. The algorithm, called multilevel halftoning, is based on the Cellular Neural Networks (CNN) paradigm. It tracks the CNN transient outputs and selects the image which is subjectively perceived to be the best when reduced to the allowed number of gray levels. The selection criterion is based

Quality assurance of texture web materials using cellular neural networks

The paper present a parallel implementation of an image processing algorithm for the on-line, non-destructive quality assurance of the non-woven, fibrous web materials. The task of the algorithm is to compute the material microstructure descriptors. The premise underlying this work is that the microstructure determines the performance of the material and characterization of the microstructure may

Digital Collaborative platforms: A challenge for both the Legislator and the Social Partners in the Nordic Model

This paper focuses on the specific problems in the labour and social security legislation as it relates to crowdworkers in the digitalised new economy, analysing their place in labour market, and especially in the collective agreements which are the standard means of regulating working conditions in the Nordic model. Sweden has a binary system where a performing party is as either an employee or s

Who counts as an employer in Sweden?

In this article, the concept of the employer is analysed for Swedish conditions from a variety of perspectives. The special difficulties that face the private sector are charted, as are the principles of the legal subject in triparty contracts with temporary employment agencies, platform work, and umbrella companies. Found to go hand in hand with the concept of employee, the concept of the employe

Collagen remodelling and plasma ascorbic acid levels in patients suspected of inherited bleeding disorders harbouring germline variants in collagen‐related genes

INTRODUCTION: Variants in collagen-related genes COL1A1, COL3A1, COL5A1 andCOL5A2 are associated with Ehlers-Danlos syndrome (EDS), a heterogeneous groupof connective tissue disorders strongly associated with increased bleeding. Of patientswith incompletely explained bleeding diathesis, a relatively high proportion were shown to harbour at least one heterozygous variant of unknown significance (VU