Controlling image capture
MARLIN Technical Manual
V2.4.0
136
Secure image signature (SIS)
SIS: Definition
Secure image signature (SIS)
is the synonym for data, which is inserted
into an image to improve or check image integrity.
With the new firmware V3.03, all CCD Marlin models can insert
•
Time stamp (1394 bus cycle time at the beginning of integration)
•
Trigger counter (external trigger seen only)
•
Frame counter (frames read out of the sensor)
into a selectable line position within the image. Furthermore the trigger
counter and the frame counter are available as advanced registers to be read
out directly.
SIS: Scenarios
The following scenarios benefit from this feature:
•
Assuming camera runs in
continuous mode
, the check of monotonically
changing bus cycle time is a simple test that no image was skipped or
lost in the camera or subsequently in the image processing chain.
•
In (synchronized)
multi-camera applications
, the time stamp can be
used to identify those images, shot at the same moment in time.
•
The cross-check of the frame counter of the camera against the frame
counter of the host system also identifies any
skipped or lost images
during transmission.
•
The cross-check of the trigger counter against the frame counter in the
camera can identify a
trigger overrun
in the camera.
The handling of the SIS feature is fully described in the Chapter
Secure image
signature (SIS)
on page 225.
Note
L
•
FirePackage
offers additional and independent checks
to be performed for the purpose of image integrity.
Details can be found in the respective documentation.