Table Of Contents

Optical Flow (Optical Flow (LK)) (G Dataflow)

Last Modified: June 25, 2019

Computes the optical flow (velocity flow) information between two successive images using the Lucas-Kanade algorithm.

connector_pane_image
datatype_icon

ROI descriptor

Descriptor that defines the region of interest (ROI) within which the optical flow is computed.

datatype_icon

global rectangle

Coordinates of the bounding rectangle.

datatype_icon

contours

Individual shapes that define an ROI.

datatype_icon

ID

Object specifying if contour is the external or internal edge of an ROI.

datatype_icon

Type

Shape type of the contour.

datatype_icon

Coordinates

Relative position of the contour.

datatype_icon

current frame

Reference to the current source image.

datatype_icon

previous frame

Reference to the previous source image.

datatype_icon

velocity component 1 in

Reference to the image that will contain the horizontal component or the magnitude component of the computed velocity at each pixel.

datatype_icon

velocity component 2 in

Reference to the image that will contain the vertical component or the phase component of the computed velocity at each pixel.

datatype_icon

error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

datatype_icon

velocity representation

Computed velocity information represented in Cartesian or polar coordinates.

datatype_icon

window size

Size of a rectangular block of pixels that are assumed to be moving with the same velocity in the image. Use a larger window size for smoother motion in the image and smaller window sizes for more turbulent motion.

datatype_icon

SizeX

Size of the window in the x dimension.

datatype_icon

SizeY

Size of the window in the y dimension.

datatype_icon

current frame out

Duplicate of the input current frame.

datatype_icon

velocity component 1 out

Reference to the image that contains the horizontal component or the magnitude component of the computed velocity at each pixel.

datatype_icon

velocity component 2 out

Reference to the image that contains the vertical component or the phase component of the computed velocity at each pixel.

datatype_icon

error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application


Recently Viewed Topics