title: Development and evaluation of different methods to assess download and display time of image web systems.
abstract: OBJECTIVE
  The aim of this study was to develop and verify different methods of measuring time-to-display (TTD) for radiological images with image web systems (IWS). The process should be automatable in order to repeatedly perform a large number of measurements without human interaction.
  
  
  METHODS
  Three methods were defined and compared with respect to usability, stability, and quality of results. Method 1 was based on Windows 2000 Performance Monitor, whereas method 2 employed phototransistors taped to the screen and connected to a separate PC. A software tool developed for method 3, which used Windows application programming interface (API) function, calls to read the color code assigned to specific pixels on the screen.
  
  
  RESULTS
  Method 3 proved to be the most reliable and easy to automate. The accuracy is practically equivalent to method 2, but it proved to be far more automatable. Method 1 produced the largest mean error, was easily disturbed, but was also easy to set up and provided additional insights into the system's architecture especially if combined with method 3.
  
  
  CONCLUSIONS
  To measure the performance of image distribution systems, any of these methods can be used, but method 3 proved to be superior.
authors.affiliation: Department of Information Technology and Biomedical Engineering, Universitätsklinikum Heidelberg, Tiergartenstrasse 15, 69121, Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Pietsch
authors.forename: A
authors.initials: A
authors.lastname: Schlaefke
authors.forename: T J
authors.initials: TJ
authors.lastname: Vogl
authors.forename: B
authors.initials: B
authors.lastname: Bergh
mesh_terms: D044962:Data Compression; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D020407:Internet; D011786:Quality Control; D011873:Radiology Information Systems; D015203:Reproducibility of Results; D012984:Software; D013995:Time