Search results for "CONTRAST"

Multi-level contrast filtering in image difference metrics

2013

In this paper, we present a new metric to estimate the perceived difference in contrast between an original image and a reproduction. This metric, named weighted-level framework Δ E E (WLF-DEE), implements a multilevel filtering based on the difference of Gaussians model proposed by Tadmor and Tolhurst (2000) and the new Euclidean color difference formula in log-compressed OSA-UCS space proposed by Oleari et al. (2009). Extensive tests and analysis are presented on four different categories belonging to the well-known Tampere Image Database and on two databases developed at our institution, providing different distortions directly related to color and contrast. Comparisons in performance wi…

SNOM study of ferroelectric domains in doped LiNbO3 crystals

2009

Abstract This work shows a study of the periodic ferroelectric domains formed in LiNbO3 crystals doped with rare earths by means of scanning near field optical microscopy (SNOM) technique. It has been observed periodic structures associated with ferroelectric domains with an unexpected high value of the optical contrast working under reflectance SNOM mode. From Raman-Nath diffraction patterns, a refractive index modulation of Δ n ∼ 1 0 − 4 has been calculated. These results were correlated with the ferroelectric periodic domains obtained by the SNOM technique. A light waveguide effects along the ferroelectric domains is suggested to explain the high reflectance contrast observed in SNOM exp…

High-contrast white-light Lau fringes

2004

We present a new optical assembly with which to achieve Lau fringes with totally incoherent illumination. Gratinglike codification of the spatially incoherent source combined with an achromatic Fresnel diffraction setup allows us to achieve Lau fringe-pattern visibility of almost 100% with broadband light. The white-light character to our proposed setup is in stark contrast to previous monochromatic implementations. Potential implications of this fact are identified.

SAFETY OF REPEATED MDCT WITH CONTRAST COMPOUND IN CASE OF PREVIOUS MILD OR MODERATE ADVERSE REACTION: A SINGLE CENTRE RETROSPECTIVE STUDY.

2015

Aims and objectives Methods and materials Results Conclusion Personal information References

Cue combination in a combined feature contrast detection and figure identification task

2006

AbstractTarget figures defined by feature contrast in spatial frequency, orientation or both cues had to be detected in Gabor random fields and their shape had to be identified in a dual task paradigm. Performance improved with increasing feature contrast and was strongly correlated among both tasks. Subjects performed significantly better with combined cues than with single cues. The improvement due to cue summation was stronger than predicted by the assumption of independent feature specific mechanisms, and increased with the performance level achieved with single cues until it was limited by ceiling effects. Further, cue summation was also strongly correlated among tasks: when there was …

Breast dynamic contrast-enhanced-magnetic resonance imaging and radiomics: State of art

2020

Breast cancer represents the most common malignancy in women, being one of the most frequent cause of cancer-related mortality. Ultrasound, mammography, and magnetic resonance imaging (MRI) play a pivotal role in the diagnosis of breast lesions, with different levels of accuracy. Particularly, dynamic contrast-enhanced MRI has shown high diagnostic value in detecting multifocal, multicentric, or contralateral breast cancers. Radiomics is emerging as a promising tool for quantitative tumor evaluation, allowing the extraction of additional quantitative data from radiological imaging acquired with different modalities. Radiomics analysis may provide novel information through the quantification…

Dynamic contrast‐enhanced magnetic resonance imaging for monitoring angiogenesis during bone regeneration – a randomized pilot study in rabbits

2020

Problemas en la estimación y en el contraste de los rendimientos anormales a largo plazo: Estado de la cuestión

2002

-Jose.E.Farinos@uv.es -Ana.M.Ibanez@uv.es El paradigma de la eficiencia ha sido puesto en entredicho en las últimas décadas como consecuencia de la obtención de rendimientos anormales, estadística y económicamente significativos, durante amplios periodos de tiempo tras algunas importantes decisiones empresariales. No obstante, los problemas conceptuales y estadísticos que presenta la medición y contrastación de los rendimientos anormales a largo plazo ha supuesto que la evidencia obtenida pase a calificarse como anomalía. Dada la escasa proliferación de este tipo de estudios en nuestro mercado y el desafortunado desarrollo de algunos de los existentes, en este trabajo presentamos estos prob…

Local Spatio-Temporal Log-Gaussian Cox Processes for seismic data analysis

2022

We propose a local version of the spatio-temporal log-Gaussian Cox processes (LGCPs) employing the Local Indicators of Spatio-Temporal Association (LISTA) functions into the minimum contrast procedure to obtain space as well as time-varying parameters. We resort to the joint minimum contrast method fitting method to estimate the set of second-order parameters for the class of Spatio-Temporal LGCPs. We employ the proposed methodology to analyse real seismic data occurred Greece between 2004 and 2015.

FOCAL LIVER LESIONS: CONTRAST-ENHANCED ULTRASOUND

2008

Contrast-enhanced ultrasound (CEUS) represents a significant breakthrough in sonography and it is being increasingly used for evaluation of focal liver lesions (FLLs). The unique feature of CEUS of non-invasively assessing in real time liver perfusion throughout the vascular phase has led to a dramatic improvement in diagnostic accuracy of US in either detection and characterization of FLLs, as well as in the guidance and evaluation of response of therapeutic procedures. Currently, CEUS is included as a part of the suggested diagnostic work-up of FLLs, resulting in a better patient management and cost-effective therapy delivering. After a brief description of the basis of different CEUS tec…