Photron FASTCAM SA-Z, Hardware Manual

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Chapter. 3 Recording
3.7. Image Trigger
This system has a function that automatically activates trigger when the target object area hits a
predetermined image output level. This is a handy function to use when you shoot a high-speed
event that does not output an effective triggering signal, or when you wish to simply automate a
recording without using an external trigger signal.
The use of this function requires the following three settings to be made in advance:
AREA, REFERENCE and RANGE
Each of the above three items will be described in this section.
•
AREA
Sets a field of interest within an image to be recorded.
The Image Trigger function activates trigger by using the averaged level of image output signal within the
field of interest set here.
•
REFERENCE
Sets the reference value of the image output signal level as criterion. The value is set by the 10-bit (0 to
1023) scale.
•
RANGE
Gives a range to the reference value of image output level set in the above step, REFERENCE. The
value is set by the 10-bit (0 to 1023) scale.
The Image Trigger function activates trigger if and when the average value of image output level within
the field set in the AREA step goes out of the range of “REFERENCE ± RANGE” values.
•
The reaction speed of the Image Trigger depends on the repeating rate of video (1/23.98 to 1/60
depending on the video format).
•
The Image Trigger is an auxiliary functionality that activates trigger based on the background
difference within the field of view while waiting for an occurrence of a target event. There is an
inevitable possibility that the system fails to trigger in the timeliest manner to capture short living
events. Therefore, the use of this functionality is NOT advisable to record important experiments
involving once –a -century type or very expensive events.
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