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Hello.
I am Catherine Plaisant, and this
is Dave Carr from the Human Computer Interaction Laboratory
of the University of Maryland.
During last year, we worked on the redesign
of a telepathology workstation user interface.
This was done with Corabi Telemetrics,
who's pioneered the commercialization
of this technology.
Telepathology is of specialized nature,
but we believe that all work will
have other applications in the field
of telemedicine and remote diagnostic in general.
First, let's see what is telepathology
and how the current system works.
In simplest terms, telepathology is the process
of viewing a patient's tissue sample
by a pathologists who is hundreds, even thousands,
of miles away.
For the patient, that means unlimited access
to medical specialists from virtually any point
on the globe.
As specialization grows, access to specialists
becomes a progressively more important issue.
And what the technology does is it
provides a mechanism where every hospital can have
ready access to specialists.
The process works like this.
A pathologist in one location places a slide
under a robotically controlled specialized microscope.
A video camera on the microscope picks up
the image of the sample and feeds it via satellite
to a high resolution video monitor in another location.
So first commercial system is now being used in Atlanta
between Emory and Grady hospital's.
Diagnosis are regularly rendered remotely,
and designed efforts are now directed at improving
the workstation usability.
Traditionally, the manipulation of the slide
under the microscope is very fast and precise.
The pathologist can move the slide by hand
to within a micron, but remote operation
implies time delays, including transmission and device
activation delays.
Limited feedback, devices are usually
not designed for remote operation
and don't send regular status feedback.
And finally, increase potential for breakdowns.
Therefore, the remote control of the microscope
remains slow and potentially frustrating for pathologists.
Of course, we could imagine first digitizing all specimens,
but this is not practical today because those little things are
really three dimensional, very high definition
objects requiring too long scan time
and huge storage space, up to a gigabyte for a case.
Therefore, the specimen has to be
observed under the microscope.
In order to study alternative interfaces and the influence
of time delays, we built a simulation
of the diagnostic workstation that Dave Carr will present.
We have brought together the various controls
onto one touch screen here.
The slider stage can be moved.
These arrow keys move the image incrementally.
Here's focus adjustment and magnification selection.
On a low resolution image of the slide,
the red rectangle shows the position of the stage.
Commands issued here are sent to the remote microscope,
which sends back high resolution image which appears here.
In our simulation, we communicate via serial line
and insert time delays.
To simplify the simulator, we do not use such realistic images.
Instead, we have an image made of color rectangles.
Imagine you had a specimen made up of small rectangles.
You would see a global view like this and a magnified image
like this.
In your simulation of the current system
using a keypad, after I press the right arrow,
the stage moves right.
And if I see something of interest, I press stop,
and it's out of the screen.
So the problem with such stop-start command
is that it's hard to estimate how early to press stop,
so stop location may not even be on the screen yet.
Of course, it's possible to backtrack
to the approximate location where I pressed stop,
but it takes time.
Alternative to the start-stop commands
are pointing to the destination or indicating how far to move.
For pointing at the destination, the rectangle can be moved.
No need to try the microscope.
No overshooting.
You know where it will stop, but when the specimen is viewed
at higher magnification, the stage movements
are too small to be specified on the global view,
so we looked at the other alternative, which
is to allow the users to specify how far to move the stage.
We chose a track ball which can be manipulated
without looking at it.
If I roll the ball a little bit, the slide moves a little bit.
If I roll the ball a lot, the slide moves a lot.
If I press stop to stop it, the side buttons are for focusing.
A pilot study compared the two interfaces
for three time delays.
The direct manipulation of the slide and the global view
was shown to be helpful to novice users.
They had short time delays.
The start-stop was faster.
Surprisingly, at longer time delays,
no significant differences were found.
User comments reflected the increased complexity and lack
of feedback about progress and the final destination.
Estimating how much to move was not easy.
Our revisions to the trackball version
include better feedback about the progress and destination
on the global view.
When I move the trackball, now I get
feedback on the global view.
I see the progress, and I can readjust the final position,
and I also get feedback on the screen with a white cursor.
This is very helpful for the small moves.
It's, once again, pointing to the destination.
When the move is larger, so cursor disappears,
but a green indicator remains, and then
I could readjust the position of the white cursor.
Macro commands should also be helpful.
In the future, a trail can be specified then
followed automatically.
Focusing up and down also seems to follow
regular patterns which can be reproduced with micro commands.
We have tested the revised trackball interface,
and the feedback made a difference, especially
for experienced users.
In addition, we tested another feature,
the use of intermediate views or local maps.
When I would press local map, the microscope image,
which also corresponds to what's in the little red rectangle,
would be digitized and will replace the whole overview
of the slide.
Now when I go from 50 to 400x, I can still see the stage
and get good feedback about my trackball move.
We run an experiment at three magnifications.
100, 200, and 400.
The task involved navigating and finding
special yellow rectangles that represented bad cells.
Users got to do that with a local map
or without the local map.
Users always felt more confident with the local map.
At one of the 100x, which corresponds
to a one 1 to 20 ratio between the global map
and the magnified view, there was no performance differences.
But at a higher ratio, users made less errors
and spent less time when they had the local map.
Therefore, local maps are very important addition
when the ratio between global view and magnified view
is more than 1 to 20, despite the added
complexity of the interface.
Looking to the future when digitizing
all views of all slides will be practical,
we are elaborating a taxonomy of the many zooming
and panning techniques to find the best
matches between navigation techniques and user tasks
Thank you.
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