Allied Guppy, Техническое руководство, Страница: 131 / 238

Controlling image capture
GUPPY Technical Manual V4.0.1
131
Example GUPPY F-033
100 x 20 µs + 24.28 µs = 2024.28 µs exposure time
The minimum adjustable exposure time set by register is 20 µs.
Æ
The real
minimum exposure time of GUPPY F-033 is then 20 µs + 24.28 µs = 44.28 µs.
Extended shutter
The exposure time for long-term integration of up to 67 seconds for the CCD-
models and up to 979 ms for the CMOS models can be extended via the
EXTENDED_SHUTTER register.
The longest exposure time, 3FFFFFFh, corresponds to 67.11 sec.
Camera Register value Timebase
GUPPY F-033 100 20 µs
Table 56: Register value and Timebase for GUPPY F-033
Register Name Field Bit Description
0xF100020C EXTD_SHUTTER Presence_Inq [0] Indicates presence of this feature (read
only)
--- [1..5]
ExpTime [6..31] Exposure time in µs
Table 57: Extended shutter configuration
Note
L
• Exposure times entered via the 81Ch register are mir-
rored in the extended register, but not vice versa.
• Longer integration times not only increase sensitivity,
but may also increase some unwanted effects such as
noise and pixel-to-pixel non-uniformity. Depending on
the application, these effects may limit the longest
usable integration time.
• Changes in this register have immediate effect, even
when the camera is transmitting.
• Extended shutter becomes inactive after writing to a
format/mode/frame rate register.