High Dynamic Range Mode (Hdr); Cmosis Multi Slope - Photon Focus MV0 3D06 Series User Manual

High Dynamic Range Mode (HDR)

To have an accurate laser line detection it is important that the pixels that represent the laser
line, are not saturated. The High Dynamic Range (HDR) mode is a special integration mode
that increases the dynamic range of the pixels, and thus avoids the saturation of the pixels in
many cases.

12.1 CMOSIS Multi Slope

The CMOSIS CMV2000 and CMV4000 sensors provide a HDR mode. It is called multi slope or
piecewise linear mode, which clips illuminated pixels which reach a programmable voltage,
while leaving the darker pixels untouched (see Fig. 12.1). The clipping level can be adjusted
once (2 slopes) or twice (3 slopes) within the exposure time.
Parameters:
Multislope_Mode There are 3 predefined HDR parameter sets: LowCompression,
NormalCompression and HighCompression. If Multislope_Mode is set to UserDefined then the
individual parameters can be set to user defined values.
Multislope_NrSlopes Number of slopes. Multislope_NrSlopes=2: 2 slopes with only knee point
B. Multislope_NrSlopes=3: 3 slopes with knee points A and B.
Multislope_Value1 Corresponds to Vlow1: the higher the value, the higher the compression.
Multislope_Time1 Time corresponding to knee point B. The value is the fraction (per mill) of
the total exposure time.
Multislope_Value2 Corresponds to Vlow2: the higher the value, the higher the compression.
This value is ignored if Multislope_NrSlopes =2.
Multislope_Time2 Time corresponding to knee point A. The value is the fraction (per mill) of
the total exposure time. This value is ignored if Multislope_NrSlopes =2.
The red line in Fig. 12.1 shows a pixel with high illumination. Without the HDR (3 slopes)
mode, the pixel would have reached its saturated value. With HDR mode, the pixel reaches
value P1 which is below the saturation value. The resulting pixel response in this case is shown
in Fig. 12.2. The blue line (P2) shows a pixel with low illumination. Its value never reaches
Vlow2 or Vlow1 at the knee points and the resulting response is linear.
The parameters Multislope_Value1 and Multislope_Value2 are only applied after
a camera trigger. Note that in free-running mode the camera trigger is applied
internally by the camera itself.
MAN083 08/2020 V1.2
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