Acquisition Handle¶

The main access principle, also within HALCON, is the manipulation of the NxLib parameter tree. Each access must be performed on a acquisition handle within Halcon. An acquisition handle is created by calling open_framegrabber. Each acquisition handle simply acts as a reference to an NxLib tree item, i.e. the handle has an associated path, usually the tree’s root or the root item of a camera.

Type

Description

‘Stereo’

Open: The device with serial number ‘<serial_number>’ will be opened automatically during handle creation.

open_framegrabber('Ensenso-NxLib', 0, 0, 0, 0, 0, 0, 'default', 0, 'Raw', -1, 'false', 'Stereo', '<serial_number>', 0, 0, AcqHandle)

If ‘<serial_number>’ is left empty, it will open the first detected stereo camera.

Parameters:

‘grab_data_items’ is set to ‘ Images/PointMap ‘ by default.

Restrictions:

In ‘ set_framegrabber_param ‘ the parameter ‘do_execute’ is not supported.

Close: The associated device will be closed upon destruction of the handle.

‘Monocular’

Open: The device with serial number ‘<serial_number>’ will be opened automatically during handle creation.

open_framegrabber('Ensenso-NxLib', 0, 0, 0, 0, 0, 0, 'default', 0, 'Raw', -1, 'false', 'Monocular', '<serial_number>', 0, 0, AcqHandle)

If ‘<serial_number>’ is left empty, it will open the first detected mono camera.

Restrictions:

In ‘ set_framegrabber_param ‘ the parameter ‘do_execute’ is not supported.

Close: The associated device will be closed upon destruction of the handle.

‘Item’

open_framegrabber('Ensenso-NxLib', 0, 0, 0, 0, 0, 0, 'default', 0, 'Raw', -1, 'false', 'Item', '<node_path>', 0, 0, AcqHandle)

If ‘<node_path>’ is left empty, it will refer to the tree’s root item.

Restrictions:

The operator ‘grab_image’ is not supported.
In ‘set_framegrabber_param’ the parameter ‘do_execute’ is only supported if the handle is referring to the tree’s root item.

Handle Parameters¶

Parameter	Values	Default	Description
auto_grab_data	‘true’, ‘false’	‘true’	If set, it simplifies the usage of ’ grab_data ‘.
parallel_execution	‘true’, ‘false’	‘false’	If set, the NxLib commands of this handle are executed in parallel to commands from other handles. See here for more information.
error_code	<error_code>		Error code from the last raised NxLib API exception.
error_item	‘<error_item_path>’		Path of the item that raised the last NxLib API exception.
error_text	‘<error_text>’		Error text from the last raised NxLib API exception.
generate_regions	‘true’, ‘false’	‘true’	Enables/disables region generation in ‘ grab_data ‘.
grab_data_items	[‘<binary_node_path>’]		List of binary nodes which will be provided when using ‘ grab_data ‘.
replace_nans	‘true’, ‘false’	‘true’	Enables/disables NaN replacement in ‘ grab_data ‘.
color_space	‘Raw’, ‘Rectified’	‘Raw’	Specifies which image will be returned in ‘ grab_image ‘.