Supported by:


Cameras equipped with a polarizing image sensor. Check for support using PxLGetCameraFeatures.


Description:


Mechanism to reduce any of the 4 polar channels, thus reducing influence light polarized to that specific channel, will have on the pixel value(s). This feature is of particular value when used with PIXEL_FORMAT_POLAR4_12, in so far as the feature can be used, for instance, to see individual polar channels. For example, if a the f45Value were set to 100, while f0Value, f90Value, and f135Value are all set to 0, then pixel value will only be influenced by light polarized to 45 degrees (clockwise from horizontal), and of course, unpolarized light. Note that when this feature is combined with PIXEL_FORMAT_POLAR4_12, the pixel values are normalized (see note below).


API Control:


PxLGetFeature, PxLSetFeature


Feature
Num Params
Parameters
Units
Restrictions
FEATURE_POLAR_WEIGHTINGS

Specifies the weighting factor to be used for each of the polar-subchannels, when determining pixel values.
4
f0Value
Percent
Limited to 100 percent
f45Value
Percent
Limited to 100 percent
f90Value
Percent
Limited to 100 percent
f135Value
Percent
Limited to 100 percent



Feature Flags:


Camera
Presence
Read Only
Auto
Manual
One-time Auto
Off
Settable While Streaming
Persistable
Cameras equipped with a polarizing sensor 
Yes
No
No
Yes
No
No
Yes
Yes



Parameter Values:


Parameter
Unit
Type
Min
Max
Default
Step Size
Comments
f0Value
Percentage
Absolute
0
100
100
0.1
Percentage contribution for the 0 degree polar channel (I0). Determines the extent to which light polarized to 0 degrees (horizontal), affects the overall pixel value.
f45Value
Percentage
Absolute
0
100
100
0.1
Percentage contribution for the 45 degree polar channel (I45). Determines the extent to which light polarized to 45 degrees (clockwise from horizontal), affects the overall pixel value.
f90Value
Percentage
Absolute
0
100
100
0.1
Percentage contribution for the 90 degree polar channel (I90). Determines the extent to which light polarized to 90 degrees (vertical), affects the overall pixel value.
f135Value
Percentage
Absolute
0
100
100
0.1
Percentage contribution for the 135 degree polar channel (I135). Determines the extent to which light polarized to 135 degrees (clockwise, from horizontal), affects the overall pixel value.


Notes:

  • Setting the fXValue of each of the 4 polar channels to 100, will have each of the polar channels contributing fully to the overall pixel values. Reducing the fXValue for a given polar channel will have 2 effects:

  • It will reduce the influence light polarized to that specific channel, has on the pixel value.

  • It will make unpolarized light, appear polarized.

When used with PIXEL_FORMAT_POLAR4_12, This feature will have the effect ‘weighted averaging’ across all requested polar channels, without losing overall intensity. Setting two of the polar channels to 100%, and the other two to 0%, will in effect average just two of the polar channels.  Setting all polar channels to 0, will result in dark pixels.  For example, say f0Value were set to 100, f45Value set to 50, and f90Value and f135Value were set to 0, then the pixel value will be weighted so that 2/3 of the value comes from the I0 sub-pixel, while 1/3 of the value comes from the I45 sub-pixel.