Performance
195
Alvium CSI-2 Cameras User Guide V2.6.2
Impact by other controls
Exposure times and frame rates with Sony IMX rolling
shutter cameras
Affected models:
Alvium 1800 C-1240 m/c and C-2050m/c
Generally, long exposure times result in low frame rates because one is roughly the
inverse of the other. With Alvium IMX RS cameras
•
The range of available frame rates depends on the exposure time.
•
The exposure time must be increased when low frame rates are used.
•
The available range for frame rate values depends on the exposure time. If by
changing the exposure time, the previous frame rate is moved out of the avail-
able range, the frame rate is adjusted automatically.
Dark current compensation
All sensors accumulate dark current in the pixels. Dark current increases the signal
level and black level. Most sensors in Alvium CSI-2 cameras compensate for this.
For
Alvium 1500 C-050m/c
with the ON Semi PYTHON 480 sensor, see
compensation for 1500 C-050m/c
If cameras are operated at high temperatures or exposure times, compensation
reaches its limits. The typical compensation mechanism uses a
margin
to
compensate for dark current. This works only until dark current reaches the size of
the margin. The following table shows the relation of the margin and accumulated
dark current for a pixel in 8-bit mode with a maximum value of 255.
Input
Output
Exposure time values
Frame rate
Exposure Time
Affected as expected
Affected
CSI-2 Lane Count
Affected
Affected
Height
Not affected
Affected
Width
May be affected
May be affected
Table 95: Impact by other controls
