A descriptor is a collection of camera feature properties that is applied to an image frame.  Since each frame can have a unique descriptor, they can be used to change camera settings on a frame by frame basis.  The "Descriptors" tab allows the user to add/modify/delete descriptors and view the resulting frame capture.

Note: For a list of cameras that support these descriptors shown in Capture OEM, please see Descriptors.

For information on the API Frame Descriptor, which contains the settings for a captured frame, please see Frame Descriptor

What is a descriptor:

  • A descriptor is a set of parameters associated with a frame that allows for rapid changes of camera parameters in a deterministic manner

  • The descriptor defines the value of each parameter 

  • Each frame can have a unique descriptor, custom descriptors can be used to change camera settings on a frame-by-frame basis for each frame in the video stream 

  • The camera will apply each descriptor in turn when capturing images and will output one frame per descriptor

  • After the last descriptor is used, the next frame in the stream will return to the first descriptor

When to use:

Descriptors are useful for obtaining different views of the same image.

  • Zooming in on several smaller regions of interest within a larger image

  • Panning to different ROI locations in the field of view

  • Obtaining images with different exposure times

  • Sequencing through various trigger inputs and General-Purpose outputs (GPOs) settings

How to use:

Descriptors can be programmed using Pixelink Capture OEM.  Most features that can be controlled via Capture OEM can be modified in a descriptor.  The exceptions are the gamma correction/look-up table feature and Flat Field Correction.

  • Select the Descriptors tab in the PxLDevApp

  • Select the Host Update mode

  • Click create to enable the first descriptor

In the Descriptor Focus

  • Select the button to the right of any of the camera control settings that are highlighted in bold 

  • Modify the value in the dialog that pops up

  • Close the dialog

Note: Changing any of the camera settings on the normal tab panels will also change the setting for the current descriptor

Add / Remove Descriptors

Descriptor Creation

  • Click on “Create”

  • You will see a new descriptor labelled “Descriptor # 1” in the tree view

  • Repeat this step for as many descriptors as desired. (ApiInvalidParameterError will be returned if you attempt to create more descriptors than the camera supports).

Descriptor Setup

  • Click on the descriptor that you wish to modify in the tree view, labelled “Descriptor # N” (where N is the number of the descriptor you wish to modify)

  • Click on the feature controls from the feature list and set the desired settings for the descriptor.

  • Repeat these steps for all descriptors.

  • Click on “Play” to see a preview of the descriptors that have been created

Descriptor Removal

  • Click on the descriptor that you wish to remove in the tree view, labelled “Descriptor # N” (where N is the number of the descriptor you wish to remove)

  • Click on “Delete”, the selected descriptor will be removed.

  • Or, to remove all descriptors at once, click on “Delete All”

Update Mode

Change a Descriptor without affecting the Camera

  • To change a descriptors settings without affecting the image being displayed, click on the desired descriptor and then click on "Host"

  • Click on the feature controls that you wish to modify

  • To apply the "Host" descriptor settings, click on "Update Now" or click on "Camera

Note: It is recommended that all changes to preset descriptors be made in "Host Mode" and updated accordingly.


Descriptor in Focus

This entry indicates which descriptor is currently in focus.

  • “none” means that no descriptors have been created

  • N/A next to a "Descriptor in Focus" means that it is not available with the camera configuration in use

  • A number would suggest the descriptor number that is currently selected