sgivisit.txt
Updated on November 28, 1997
November 13, 1997
MEMORANDUM
To: William Luttge, Ph.D.
From: Richard Rathe, M.D.
Subj: Insights Gained From the October Visit to SGI
1. The audiovisual specialist I spoke with confirmed that a
building-wide cable television system continues to be the most
cost-effective means to distribute full motion video at moderate
resolution. Such a system would require a single coaxial cable to each
location where it will be used. These signals could be selected and viewed
on standard television equipment or on personal computers equipped with
tuner cards.
2. Current analog technologies apparently are capable of handling much
higher resolutions than S-video (approximately 450 lines). The audiovisual
consultant I spoke with suggested that we plan for five wire, RGB + H/V
(red green-blue + horizontal/vertical) to every location where we
anticipate the need for true high resolution video. Looking to the future,
the same consultant suggested that the next generation of systems will use
so-called "component" signals requiring six wires. The marginal cost of
adding a sixth wire is likely to be small, so I recommend that we add an
extra wire to each location in anticipation of future needs.
3. I was impressed that the high resolution projection systems at 561
seemed to handle our digital and analog materials rather well. I believe
in most cases the limiting factor was not the resolution of the projection
systems themselves. In the case of the JPEG images we pre-scanned, I
believe we saw the limitations of our scanner and perhaps the JPEG format
itself. In the case of the slide-to-video projector, we must keep in mind
that our projector is over 10 years old and the images we saw were
"quadrupled" from approximately 250 lines of resolution. When you consider
this I think it's quite remarkable how good they looked. It is my
understanding that the
latest generation of slide-to-video/digitizers are capable of
matching the projector's resolution pixel for pixel.
4. I believe we have learned from this experience that not all medical
images are created equal. I was surprised that the angiography slide
looked as bad as it did. This may have been due to the high degree of
contrast in this particular image. I would not be surprised if there are
categories of medical images that even a state-of-the-art system will have
trouble with.