grab_data¶

This operator is used to access the binary nodes of the NxLib API Tree.

Parameters¶

grab_data (Image, Region, Contours, AcqHandle, Data)

Parameter	Description
Image	Variable where the retrieved image will be stored. Note: If ‘grab_data_items’ contains multiple items, this will be a tuple of images.
Region	Region which describes the valid 3D points. Note: If ‘grab_data_items’ contains multiple items, this will be a tuple of regions.
Contours	Not used.
AcqHandle	An acquisition handle obtained via ‘ open_framegrabber’.
Data	Not used.

Dependencies¶

All dependencies can be manipulated with ‘ set_framegraber_param’.

Parameter	Description
grab_data_items	Contains the list of binary nodes which will be returned in the Image value. Depending on the type of the acquisition handle following binary nodes can be accessed:
	‘Stereo’	Binary node		Image Type
		Images/Raw/Left, Images/Raw/Right		1 channel / Byte
		Images/Rectified/Left, Images/Rectified/Right		1 channel / Byte
		Images/WithOverlay/Left, Images/WithOVerlay/Right		3 channel / Byte
		Images/DisparityMap		1 channel / Byte
		Images/PointMap		3 channel / Byte
		Images/Normals		3 channel / Byte
	‘Monocular’	Images/Left		1 channel / Byte
		Images/Left		1 channel / Byte
		Images/WithOverlay/Left		3 channel / Byte
	‘Item’ (referring to root)	Images/RenderPointMap		1 channel / Byte
		Images/RenderPointMapTexture		1 channel / Byte
		Images/RenderView		3 channel / Byte
auto_grab_data	If ‘auto_grab_data’ is set, ‘grab_data’ will also automatically capture a new image and execute all necessary commands to generate the binary nodes listed in ‘grab_data_items’.
	Binary node		Execute commands
	Images/Raw/Left, Images/Raw/Right		cmdCapture
	Images/Rectified/Left, Images/Rectified/Right		cmdCapture, cmdRectifyImages
	Images/DisparityMap		cmdCapture, cmdComputeDisparityMap
	Images/PointMap		cmdCapture, cmdComputeDisparityMap, cmdComputePointMap
	Images/Normals		cmdCapture, cmdComputeDisparityMap, cmdComputePointMap, cmdComputeNormals
	Images/Left		cmdCapture,
	Images/Rectified		cmdCapture, cmdRectifyImages
	Images/RenderPointMap		cmdCapture, cmdComputeDisparityMap, cmdComputePointMap
	Images/RenderPointMapTexture		cmdCapture, cmdComputeDisparityMap, cmdComputePointMap
	Images/RenderView		cmdCapture, cmdComputeDisparityMap, cmdRenderView
replace_nans	All internal binary fields use the NaN (“Not a number”) value of the IEEE floating point format to indicate that a certain point is invalid (i.e. not triangulated). Unfortunately NaN values within images cause various problems within Halcon, therefore by stetting this flag to ‘true’, ‘grab_data’ replaces NaN values within floating point images with 0.
generate_regions	By deactivating this flag, ‘grab_data’ no longer delivers the Region value. This can be used to save computation time.

Note

All automaticallly executed commands will be run without parameters. The operator automatically enables the projector for stereo cameras.

Example¶

* Open default stereo camera
open_framegrabber('Ensenso-NxLib', 0, 0, 0, 0, 0, 0, 'default', 0, 'Raw', -1, 'false', 'Stereo', '', 0, 0, AcqHandle)

* Set 'grab_data_items'
* 'grab_data_items' is by default 'Images/PointMap' for Stereo handles
set_framegrabber_param (AcqHandle, 'grab_data_items', ['Images/DisparityMap','Images/PointMap'])

* Grab images with 'auto_grab_data' on
grab_data (Image, Region, Contours, AcqHandle, Data)

* Without 'auto_grab_data' following commands would be needed for the same result:
* Note that in this case, you have to enable the projector manually if you need it!
set_framegrabber_param (AcqHandle, 'auto_grab_data', 'false')
open_framegrabber('Ensenso-NxLib', 0, 0, 0, 0, 0, 0, 'default', 0, 'Raw', -1, 'false', 'Item', '/', 0, 0, RootHandle)
set_framegrabber_param (RootHandle, 'do_execute', 'Capture')
set_framegrabber_param (RootHandle, 'do_execute', 'ComputeDisparityMap')
set_framegrabber_param (RootHandle, 'do_execute', 'ComputePointMap')
grab_data (Image, Region, Contours, AcqHandle, Data)