TM
USING Scan Do
SCAN CONVERTERS IN
USABILITY LAB APPLICATIONS
MARKET: Research, Analysis,
Training
DOC. NUMBER: T-11
Usability labs are designed to evaluate the ease of use, effectiveness and ergonomics of computer
software and hardware. When studying software usability, researchers typically examine issues such as
whether a program’s human interface is intuitive by design and how well, in practice, the software accom-
plishes the objectives for which it is designed. For hardware, such as keyboard, mouse, trackball and
graphic tablets, researchers evaluate the ergonomics of the products’ design.
In order to perform effective analyses, researchers must be able to observe and then repeatedly review
both the human interaction with the software and hardware and the graphic output as it appeared on the
monitor. This requires the recording of the subjects’ interactions with the test products. This TECHniques
illustrates how CSI’s family of Scan Do
®
computer-to-video scan converters may be employed in a usabil-
ity lab setting to best record the images from the computer monitor, which may then be integrated with
camera shots of the subject interacting with the software and hardware. This combined capturing of infor-
mation can provide the researcher with the most complete picture of the subject’s “test experience”, there-
fore aiding him in developing recommendations for the refinement of the test products.
Often in usability labs, a
camera will be used to ob-
serve and record the image on
the computer monitor’s screen
along with the accompany ac-
tions of the computer opera-
tor. Two problems arise in this
scenario. First of all, because
a computer video signal is not
synchronous with a standard
video signal, an annoying hori-
zontal bar will constantly roll
through the recorded image of
the computer monitor’s screen. In addition, if the com-
puter operator is positioned squarely in front of the
computer monitor, the video camera must be placed
at an angle, thus providing a distorted perspective
of the monitor screen.
Scan Do provides a sharp, “straight-on” picture of
the computer monitor’s output in a format that can
be recorded to videotape without any rolling bars. In
addition, the unit is unobtrusive and therefore will
not interfere with the computer operator’s actions.
Scan Do may be used in any usability lab setting,
from simple, over-the shoulder, single-camera set-
ups, to sophisticated testing facilities that include
several cameras for observing posture and hand and
eye movements combined with timing mechanisms.
In the most simple, single-camera setup, Scan Do
may be used to simultaneously observe and record
the computer screen while a camera captures the
human response. For this application, Scan Do Select
is most appropriate. It is compatible with computer
resolutions up to 1280x1024 and features picture
sizing from 85% up to 200% so that the complete
computer screen or enlarged portions are viewable
in the standard video formats. In addition, Scan Do
Select’s four levels of anti-flicker filtering eliminate
disturbing jitter of fine horizontal lines, like those found
in spreadsheets, fine text and desktop icons.
Scan Do and TwinSplit are registered trademarks of Communications Specialties, Inc.
© 1999, Communications Specialties, Inc.