ALLIED Vision Technologies Guppy F-503 User Manual
Page 101
Description of the data path
GUPPY Technical Manual V7.1.0
101
Readout schemes: GUPPY interlaced models
(F-038, F-038 NIR, F-044, F-044 NIR, F-025,
F-029)
The GUPPY F-038/038 NIR/044/044 NIR/025/029 cameras use so-called
interline scan interlaced CCDs.
Interlaced means: one complete image is scanned or reconstructed by a tem-
poral succession of odd lines and interleaved even lines.
NIR means: near infrared. These sensors are equipped with the SONY EXview
HAD technology improving sensitivity (also in the near infrared light region:
700 nm to 1000 nm).
Advantages of interlaced CCDs compared to progressive CCDs:
•
More simple shift register (2-phase shift register per pixel element com-
pared to progressive CCDs with 3-phase shift register per pixel element)
and higher fill factor of pixels
•
Vertical binning (aka field integration) increases sensitivity by a factor
of two
•
Very sensitive EX-View HAD sensors available (PAL/NTSC resolution)
In the following chapters the 3 different readout modes of the GUPPY inter-
laced models are explained:
•
Format_7 Mode_0: interlaced, field integration (vertical binning)
•
Format_7 Mode_1: interlaced, frame integration
•
Format_7 Mode_2: non-interlaced, field integration (horizontal + verti-
cal binning), so-called progressive readout mode
4-phase vertical shift register
The interline interlaced CCDs use 4-phase vertical shift register and two gates
for two vertical pixels. The gates are used to control field or frame integra-
tion:
•
Field integration: the two gates are activated at the same time
– see
Figure 51: Format_7 Mode_0: 4-phase vertical shift register pre-
–
Figure 57: Format_7 Mode_2: 4-phase vertical shift register pre-
charging (non-interlaced, field)
•
Frame integration: the two gates are activated every other field
– see
Figure 54: Format_7 Mode_1: 4-phase vertical shift register pre-
•
Pre-charging of the phases defines interlaced or non-interlaced.
Note
For demosaicing process outside of the camera, see Chapter