ALLIED Vision Technologies Guppy F-503 - Manual (Page 188)

Controlling image capture
GUPPY Technical Manual V7.1.0
188
• Line 1 shows the broadcast command, which stops all cameras con-
nected to the same IEEE 1394 bus. It is generated by holding the Shift
key down while clicking on Write.
• Line 2 generates a broadcast one-shot in the same way, which forces all
connected cameras to simultaneously grab one image.
Jitter at start of exposure
The following chapter discusses the latency time which exists for all CCD
models when either a hardware or software trigger is generated, until the
actual image exposure starts.
Owing to the well-known fact that an Interline Transfer CCD sensor has both
a light sensitive area and a separate storage area, it is common to interleave
image exposure of a new frame and output that of the previous one. It makes
continuous image flow possible, even with an external trigger.
• The Micron/Aptina CMOS sensor of the GUPPY F-036 uses a pipelined
global shutter, thus imitating the separate light sensitive and storage
area of a CCD. For more information see Chapter
Pipelined global shutter
(only Guppy F-036) on page 168.
• The Micron/Aptina CMOS sensor of the GUPPY F-503 uses an elec-
tronic rolling shutter and a global reset release shutter. For more
information see Chapter
Electronic rolling shutter (ERS) and global reset
release shutter (GRR) (only Guppy F-503) on page 169.
For the CCDs the uncertainty time delay before the start of exposure depends
on the state of the sensor. A distinction is made as follows:
FVal is active  the sensor is reading out, the camera is busy
In this case the camera must not change horizontal timing so that the trigger
event is synchronized with the current horizontal clock. This introduces a
max. uncertainty which is equivalent to the line time. The row time depends
on the sensor used and therefore can vary from model to model.
FVal is inactive  the sensor is ready, the camera is idle
In this case the camera can resynchronize the horizontal clock to the new
trigger event, leaving only a very short uncertainty time of the master clock
period.
Model Camera idle Camera busy
Guppy F-033 40.69 ns 32.29 µs
Guppy F-036 29.89 µs 29.89 µs
Guppy F-038 8.77 µs 68.06 µs
Guppy F-038 NIR 8.77 µs 68.06 µs
Table 70: Jitter at exposure start