Improving image quality and interactivity in free-viewpoint video transmission

Author(s):  
Hiroya Sannomiya ◽  
Norishige Fukushima ◽  
Yutaka Ishibashi
2019 ◽  
Vol 64 (4) ◽  
pp. 373-382
Author(s):  
Bennet Hensen ◽  
Urte Kägebein ◽  
Marcel Gutberlet ◽  
Kristina I. Ringe ◽  
Van Dai Vo-Chieu ◽  
...  

Abstract Purpose To analyze the interference between a wireless high definition multimedia interface (WHDMI) and magnetic resonance imaging (MRI) image quality at 1.5T, 3T and 7T. Materials and methods A wireless video transmission system (WVTS) consisting of a WHDMI and a projector was used to transmit and display a video stream into the magnet room. MR image quality was analyzed at 1.5T, 3T and 7T. Signal-to-noise-ratio $(\overline {{\rm{SNR}}} )$ and radio frequency (RF)-noise spectrum were measured at three transmitter positions (A: inside the cabin, B: in front of the waveguide and C: in the control room). WVTS system functionality tests included measurements of reliability, delay and image quality. Results With the WVTS mean $\overline {{\rm{SNR}}} $ values significantly decreased in comparison to the reference for all positions and fieldstrenghts, while the spectra’s baseline is elevated at 1.5T and 3T. Peaks related to continuous wave interferences are apparent at all field strenghts. For WHDMI alone mean $\overline {{\rm{SNR}}} $ values were stable without significant differences to the reference. No elevation of the spectra’s baseline could be observed. Functionality measurements confirmed high connection reliability with stable image quality and no delays for all field strengths. Conclusion We conclude that wireless transmission of video streams into the MRI magnet room is feasible at all field strengths without hampering image quality.


2014 ◽  
Vol 29 (3) ◽  
pp. 290-293 ◽  
Author(s):  
Srikar Adhikari ◽  
Michael Blaivas ◽  
Matthew Lyon ◽  
Stephen Shiver

AbstractObjectiveDisaster management is a complex and difficult undertaking that may involve limited health care resources and evaluation of multiple victims. The objectives of this study were to evaluate the feasibility of real-time ultrasound video transmission from a simulated disaster triage location via commercially available video mobile phones and assess the ability of emergency physicians to accurately interpret the transmitted video of Focused Assessment with Sonography for Trauma (FAST) ultrasound examinations.MethodsThis was a prospective, observational study that took place at a simulated disaster scene put on for an Advanced Disaster Life Support (ADLS) course. The second component occurred at a Level I academic urban emergency department (ED) with an annual census of 78,000. Nineteen subjects at a simulated disaster scene were scanned using a SonoSite Titan ultrasound system (Bothell, Washington USA). An off-the-shelf, basic, video-capable mobile phone was used to record each ultrasound examination; and then immediately transmit the videos to another mobile phone approximately 170 miles away. The transmitted video was received by three emergency physicians with hospital credentialing in emergency ultrasound. Each FAST examination video was assessed for pathology, such as free fluid. The reviewers graded the image quality and documented the overall confidence level regarding whether or not a complete and adequate examination was visualized. Spearman's rank correlation coefficient was used to examine the agreement between the reviewers and the sonologist who performed the ultrasound examinations.ResultsA total of 19 videos were transmitted. The median time for transmission of a video was 82.5 seconds (95% CI, 67.7 seconds-97.3 seconds). No video failed to transmit correctly on the first attempt. The image quality ratings for the three reviewers were 7.7, 7.5, and 7.4 on a 10-point Likert scale. There was a moderate agreement between the reviewers and sonologist in image quality rating and overall confidence level scores (rho = 0.6).ConclusionsReal-time portable ultrasound video transmission via commercially available video mobile phones from a simulated disaster triage location is feasible and emergency physicians were able to accurately interpret video of FAST ultrasound examinations.AdhikariS, BlaivasM, LyonM, ShiverS. Transfer of real-time ultrasound video of FAST examinations from a simulated disaster scene via a mobile phone. Prehosp Disaster Med. 2014;29(3):1-4.


Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.


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