Redlake MASD MegaPlus ES 4.0/E, Руководство пользователя

Страница: 17 / 40

Mega Plus
®
Model ES 4.0/E
3.4.4 Continuous Fluoroscopy
This mode is similar to the Continuous mode, except that the electronic shutter is not used. The
exposure time in continuous fluoroscopy mode is equal to the frame rate time. A frame rate of 30
fps means that the exposure time is 33.3 milliseconds. Since the exposure is fixed, the software
control of exposure is disabled in this mode.
3.4.5 Controlled
The start and exposure time of each image is controlled by input signals supplied by the user to
the EXPOSE input pins in the digital interface connector or the trigger input on the rear panel of
the camera. The exposure time is equal to the time the EXPOSE input signal is true. The frame
rate is inversely proportional to the exposure plus the readout time. The exposure time is
unlimited, but at room temperatures, dark field nonuniformities become noticeable with exposure
times greater than 100 milliseconds.
3.4.6 Trigger
Each exposure is started by a signal connected to the EXPOSE input pins of the digital interface
connector or the trigger input on the rear panel of the camera. The exposure command sets the
exposure time. An exposure starts 17 microseconds (± 100 nanoseconds) after the active edge
of the trigger pulse and ends at the exposure time selected by the EXE command. Use the TRM
command to select the positive or negative edge of the trigger pulse as the trigger point.
The EXPOSE input sets the start time for each frame of video. The camera will ignore additional
EXPOSE signals until it completes the current exposure. The trigger mode of operation is used
to capture a single image or a sequence of images.
3.4.7 Double Exposure
The double exposure sequence begins after receiving a trigger input through the digital connector
or the TRIGGER connector on the rear panel of the camera. The camera captures the first image
in the photo diode array, and then transfers this image to the CCD array. The first image is
transferred from the CCD to the internal frame store while the second image is being captured by
the photo diode array. The second image is then transferred into the CCD array and from there
to the internal frame store’s second image buffer.
When operating in Double Exposure mode, the maximum frame rate is approximately 11.4 fps
due to the necessity for 2 frames per trigger. The camera will ignore triggers that it cannot
accept; so more than 5.7 triggers per second will result in slower operation. If the trigger rate is
set lower, the camera will track the trigger rate exactly.
91000116-001 Revision B 3-3 USER’S MANUAL