ALLIED Vision Technologies Marlin F-201 - Manual (Page 68)

Description of the data path
MARLIN Technical Manual V2.4.0
68
This dual slope reset pulse resets the analogue signal of the pixels below the
dual slope reset level to this level. After the reset, the analogue signal starts
to decrease with the same slope as before (pink P3 and yellow P4 lines).
This introduces a knee-point in the exposure function.
If the dual slope reset pulse is placed at the end of the integration time (90%
for instance), the analogue signal which would have normally reached the
saturation level is no longer saturated at read out. This effect increases the
optical dynamic range of the sensor.
It is important to notice that pixel signals above the dual slope reset level
will be left unaffected (green P1 and green P2).
MARLIN F-131 with three knee-points
The MARLIN F-131 offers up to three knee-points when in global shutter
mode. This functionality is controlled via the following registers.
Register Name Field Bit Description
0xF1000280 HDR_CONTROL Presence_Inq [0] Indicates presence of this
feature (read only)
--- [1..5] Reserved
ON_OFF [6] Enable/disable HDR mode
--- [7..19] Reserved
MaxKneePoints [20..23] R: Number of knee-points
possible in this mode
--- [24..27] Reserved
KneePoints [28..31] W: Number of active knee-
points
0xF1000284 KNEEPOINT_1 --- [0..15] Reserved
Kneepoint1 [16..31] R/W: Time in µs
0xF1000288 KNEEPOINT_2 --- [0..15] Reserved
Kneepoint2 [16..31] R/W: Time in µs
0xF100028C KNEEPOINT_3 --- [0..15] Reserved
Kneepoint3 [16..31] R/W: Time in µs
Table 27: High dynamic range configuration register
Note
L
It is recommended that knee-points be adjusted to 10 %, 5 %
and 2.5 % of the total exposure or shutter time being applied
at the end of the exposure.