Methods of measurement of image quality in teleultrasound.

Abstract

In recent years, teleultrasound has emerged as a potentially effective method of provision of ultrasound services to remote areas of the community. Transmission of teleultrasound, however, requires a high degree of compression when utilizing the relatively low bandwidth ISDN connections available within the UK. The actual amount of compression occurring varies both with the connection and the image content, often on a frame to frame basis. For this reason, traditional measurements of image quality using test tools are ineffective. Most studies to date have assessed equipment performance by testing diagnostic performance. Although this is the most important method of assessing the results of image degradation, few studies have attempted to perform physical measurements of degradation. The aims of this study were to measure the amount of degradation within a teleultrasound system and, using a number of methods, to ascertain the most useful indicators of loss of image quality. Groups of successive abdominal ultrasound images were captured and digitized both before and after degradation via an ISDN6 teleultrasound system. Normalized mean squared error (NMSE), pixel histograms, line and surface plots, Fourier spectra and contrast measurements were carried out on regions of interest in both sets of images. The NMSE was most sensitive to degradation, with alterations in the NMSE value depending on image content and degree of degradation. Fourier analysis was also indicative, showing consistent changes in high frequency content again varying with image content.

Image Quality in Real-Time Teleultrasound of Infant Hip Exam Over Low-Bandwidth Internet Links: a Transatlantic Feasibility Study

“…It was also found, with regard to diagnostic quality, that there was mild degradation in gray scale, brightness, and contrast of the images and the main effect is that of loss of high-frequency data [34,37].…”

“…DICOM standard is not applicable to video sequences apart from storage of sequences as separate images [34]. In our study DICOM is not used.…”

“…Earlier research has shown that the normalized mean squared error is a very sensitive test of image degradation but is completely non-specific as it conveys no spatial information [34]. It was also found, with regard to diagnostic quality, that there was mild degradation in gray scale, brightness, and contrast of the images and the main effect is that of loss of high-frequency data [34,37].…”

A Blurring Index for Medical Images

“…4,8,9 However, both MSE and NMSE do not correlate well with image quality measurements and ROC studies are timeconsuming.…”

Descrição de uma ferramenta digital e de um ambiente virtual para fins de segunda opinião em oftalmologia

“…A utilização da internet torna-se praticamente compulsória para estes fins dada a facilidade e o baixo custo da transmissão das informações, permitindo uma eficiente veiculação e troca de imagens, sons e textos a partir de praticamente qualquer computador pessoal (3) . Os serviços de aconselhamento diagnóstico já existem em áreas como a cardiologia, radiologia e dermatologia (4)(5)(6) . A oftalmologia, por ser uma especialidade cujo diagnóstico se baseia preferencialmente em imagens, tem uma vocação natural para esta modalidade (7) .…”