Halcon Interface > Operators > set_framegrabber

This operator is used to set interface parameters or to write directly into the NxLib API Tree.

Parameters

set_framegrabber_param (AcqHandle, Parameter, Value)

Parameter	Description
AcqHandle	An acquisition handle obtained via 'open_framegrabber'.
Parameter	This can either be an interface parameter or an item path for direct tree item access.
Value	A variable or constant to be written to the item.

Halcon Interface Parameters

Parameter	Values	Type	Description
'auto_grab_data'	'true', 'false', 0, 1	string, integer	Set the 'auto_grab_data' flag for the given handle.
'do_open_tcp_port'	<port>	integer	Opens a TCP port. Note: Only one port can be open per NxLib instance.
'do_close_tcp_port'	[]		Closes open TCP port.
'do_execute'	'<command>'	string	Executes '<command>' in the NxLib. More information about this parameter can be found here. Note: This parameter is only supported on handles referencing the tree's root node.
'generate_regions'	'true', 'false', 0, 1	string, integer	Set the 'generate_regions' flag for the given handle.
'grab_data_items'	['<binary_node_path>']	string, tuple	List of binary nodes which will be provided when using 'grab_data' on the given handle.
'replace_nans'	'true', 'false', 0, 1	string, integer	Set the 'replace_nans' flag for the given handle.

Tree Item Access

set_framegrabber_param(AcqHandle, ItemPath, Value)
set_framegrabber_param(AcqHandle, ItemPath, [TypeSpecifier, Value])

Parameter

Values

Description

AcqHandle

An acquisition handle obtained via 'open_framegrabber'.

ItemPath

A path to a tree item to be written. The item path is relative to the path with which the handle is associated.

TypeSpecifier

'string', 'json', 'apply', 'image'

A string specifying how the Value is to be interpreted and stored. For further information read the section below.

•'string':	Specifies that Value is a plain string to be stored at the specified item.
•'json':	Specifies that Value is a string to be interpreted as JSON. The resulting JSON item(s) will be stored at/below the item specified by ItemPath.
•'apply':	Same as 'json', but the resulting JSON structure will be written with the parameter onlyWriteableNodes == true in nxLibSetJson. This should be used to apply saved parameter subtrees. Non-writable nodes will be skipped without notice.
•'image'	Used to write an image into a binary node. Note: Only images of the same dimension as the image already in the node can be used.

Value

A variable or constant to be written to the item.

Interpretation of parameter format

When setting a tree item with 'set_framegrabber_param', the HALCON parameter types int and double are written as JSON type Number.

But a HALCON string as parameter could have different meanings:

•It could be a string that should be set on the specified item

•It could be a JSON representation to be stored in the specified item

•It could be a JSON representation to be 'applied' at the specified item, skipping read-only nodes without raising an error

When specifying a string parameter, the order of interpretation is as follows:

•Try to interpret the given string as JSON. If successful, store the given JSON structure at the specified item.

•If the JSON interpretation failed, store the string in the specified item

The interpretation can be specified explicitly using the TypeSpecifier parameter.

Example

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

* Open and close TCP port 24000
set_framegrabber_param (AcqHandle, 'do_open_tcp_port', 24000)
set_framegrabber_param (AcqHandle, 'do_close_tcp_port', [])

* Set a Handle Parameter
set_framegrabber_param (AcqHandle, 'replace_nans', 'false')
set_framegrabber_param (AcqHandle, 'grab_data_items', ['Images/DisparityMap','Images/PointMap'])

* Tree Access
set_framegrabber_param (AcqHandle, 'Parameters/Capture/AutoExposure', 'false')
set_framegrabber_param (AcqHandle, 'Parameters/Capture/Exposure', 5)
* with JSON string
set_framegrabber_param (AcqHandle, 'Parameters', ['apply','{"Capture":{"AutoExposure":false, "Exposure":5}}'])

* Write an image into a binary node
read_image(Image, 'example.png')
obj_to_integer (Image, 1, -1, SurrogateTuple)
set_framegrabber_param(AcqHandle, '/Images/Raw/Left', ['image', SurrogateTuple])