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100 MicroMAX System User Manual Version 6.C
Image 1
EXT. SYNC. (A)
Images
t
trig
Mechanical
Shutter
8 ms
8 ms
NOT SCAN
t
trig
Image 2
No Signal
Integration
t
exp
t
exp
200 ns200 ns
READY
Figure 57. ESABI Timing Example: Image Exposure time = t
exp
set in software
Note: The input trigger pulse, t
trig
, must be shorter than the exposure time t
exp
. Otherwise
the second image will occur immediately after the first.
Summary of ESABI Timing mode
• The exposure time selected in Experiment Setup sets the exposure time of both the
first and second image.
• Requires that the switch, if present on the back of the camera, be set to ACTIVE.
• An externally derived trigger edge applied to Ext Sync is required to begin each
image exposure period.
• goes low when the system is ready to capture each image.
Tips and Tricks
Lab Illumination
In DIF measurements, it is necessary to remain mindful of the possibility of laboratory
light affecting the images. Because the first image can be timed with precision, laboratory
light that reaches the camera would generally not be a problem in the first image,
particularly if the capture time is short (few microseconds). The second image, on the
other hand, is much more susceptible to degradation from laboratory illumination
because, even though the second image time may be set to just a few microseconds, the
time to close the shutter, ~8 ms, must be added to that value. Light impinging on the
photosensors during that time will be integrated with the second image. Unless the
experiment is arranged so that background light can’t reach the camera, or unless the
signal is quite bright, the possibility of the second image becoming degraded must be
considered. Where this is source of degradation is a problem, the solution may be to
sharply reduce the laboratory illumination. It should be noted though, that the signal from
many strobed measurements will be sufficiently bright to allow normal laboratory
illumination to be maintained.
Background Subtraction
In any of the double imaging modes, a good idea would be to block both of your light
sources and go ahead and take two images in the same DIF mode and with the same
settings as will be used for the real measurements. That result will be two background
images that can later be subtracted from the experimental data images.