Supported by ...


  • The PL-B740 series cameras have up to three extended shutter knee points.
  • The PL-B760 series cameras have up to two extended shutter knee points.
  • The PL-D721 series cameras have up to two extended shutter knee points.


Description


Extended shutter allows for a multiple slope integration to extend the dynamic range of the camera.  The multiple slope operation is controlled using knee points, where each knee point occurs at a separate time during the overall integration. Each knee point represents a separate reset point for the image where pixels brighter than a certain value are reset to that value. For example the 741 camera can have up to three knee points when operating in extended shutter mode.  When the first knee point occurs, all pixels that are over 25% of saturation are reset to 25% of saturation. When the second knee point occurs all pixels that are over 50% of saturation are reset to 50% of saturation, and when the third knee point occurs all pixels over 75% of saturation are reset to 75% of saturation. This enables the capture of images where information can be retrieved from both dark areas of the scene that require long integration times, and bright areas that require short integration times.


The value that is set for each knee point is the time from the start of integration to when the knee point occurs.  Each knee point must have a greater time than the previous knee point and all knee point times must be less than the overall integration time.  The effect in the image is to reset the pixel at that time and to integrate until the end of the overall integration time. 


Hence, as the knee point time becomes longer, the integration time shortens and the dynamic range expands in bright areas of the image.


        Note: The PL-B760 series cameras have a limitation in that, when the trigger feature is OFF. The first knee point cannot occur during the readout of the previous frame. The duration of the readout is dependent on the frame rate and exposure time.  Use PxLGetFeatures to determine the minimum and maximum values allowed for each knee point.


        Note: Knee points are not allowed when using trigger modes 1 and 2,where the exposure time is determined by external signals.



API Control

PxLGetFeaturePxLSetFeature



Feature ID
Number of Parms
Parameters
Units
Restrictions
FEATURE_EXTENDED_
SHUTTER


>Extended shutter control, 

allows multiple knee points.

5
fNumberKnees
N/A
Integer Only
Must be less than the 
integration time.


Must be less than the integration time 
and greater than Knee point 1


Must be less than the integration time 
and greater than Knee point 2


Must be less than the integration time 
and greater than Knee point 3.



Feature Flags


Camera
Pressure
Read Only
Auto
Manual
One-time Auto
Off
CiD
PL-B740
Yes
No
No
Yes
No
Yes
Yes
PL-B760
Yes
No
No
Yes
No
Yes
Yes
PL-D721
Yes
No
No
Yes
No
Yes
Yes

Parameters

Camera
Parameter
Unit
Type
Min
Max
Default
Step Size
Comments
PL-B740
# Knee Points
Knees
Absolute
0
3
0
1

Seconds

Absolute
0.00004
1
0.04
0.00001
Must be less than the integration time.
Seconds

Absolute
0.00005
1
0.04
0.00001
Must be less than the integration time and greater than knee point 1
Seconds

Absolute
0.00006
1
0.04
0.00001
Must be less than the integration time and greater than knee point 2
PL-B760
# Knee Points
Knees
Absolute
0
2
0
1

Seconds

Absolute
Varies
Varies
0.012
Between 45 and 60 us
Min and max values vary with the trigger mode and frame rate.

The value must be less than the integration time. See note.

Seconds

Absolute
Varies
Varies
0.012
1
Must be less than the integration time and greater than knee point 1.
PL-D721
# Knee Points
Knees
Absolute
0
2
0
1

Seconds

Absolute
Varies
Varies
Varies
0.00001
Must be less than the integration time.
Seconds

Absolute
Varies
Varies
Varies
0.00001
Must be less than the integration time and greater than knee point 1.

        Note: The PL-B760 series cameras have a limitation in that, when the trigger feature is OFF, the first knee point cannot occur during the readout of the previous frame. The duration of the readout is dependant on the frame rate and exposure time. Use PxLGetFeature to determine the minimum and maximum values allowed for each knee point.