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Chapter 7 MicroMAX DIF Camera 99
first image exposure time. The controller signal goes low when the
camera is ready to begin imaging.
Figure 56 illustrates an EEC timing example.
EXT. SYNC. (A)
Images
t
exp
Mechanical
Shutter
8 ms
8 ms
NOT SCAN
Image 1
t
sync
Image 2
200 ns
READY
Figure 56. EEC Timing Example with Exposure Time in Software Set to t
exp
Summary of EEC Timing mode
• Enables double image capture under external control.
• Requires that the switch, if present on the back of the camera, be set to INACTIVE.
• The width of the pulse applied to Ext Sync sets the exposure time of the first image.
The Exposure Time set in software on the Experiment Setup Main tab page sets the
second image time, at the end of which the shutter begins to close.
• An external trigger is required to initiate the imaging process. The goes low
when the system is ready. Once
is low, an external trigger applied to the
Ext Sync connector initiates the double image capture.
ESABI (Electronic Shutter Active Between Images)
The last timing mode, ESABI, allows separation time between the two images. This
mode gives the user the ability to capture two images and use the interline chip’s
electronic shutter feature between images so that no signal is integrated in the time
between. The exposure time for both images is the same but they can be separated in
time. Each time the camera is ready to receive a trigger,
goes low. Thus
goes low twice during each ESABI cycle and the controller can be triggered
once by a sync pulse applied to Ext Sync each time. Thus two sync pulses are required,
one for each image, during each double capture. The programmed Exposure Time as set
on the Experiment Setup Main tab page sets the first image time and the time after the
start of the second image time when the shutter begins to close.
Figure 57 illustrates
ESABI m
ode timing.
Note that charge produced by light impinging on the photosensors during the interval
between the two im
ages is discarded and does not affect the second image. The time
between the first and second image can be as long as required according to the
experimental requirements. This can be particularly useful in fluorescence measurements.
By doing captures with different intervals between the two images, the fluorescence
decay characteristics can be easily measured.