Table Of Contents
Find Pattern (G Dataflow)
Searches for a template image in a rectangular search area of the image.
image in
Reference to the source image.
template image
Reference to the image to locate during the match process.
The template image is the image obtained from the output of the Learn Pattern node. If the template has not been learned, this node first goes through the learning process.
search rectangle
Rectangular search area in an image.
The left, top, right, and bottom coordinates describe a non-rotated rectangle. The rotation specifies the rotation angle of the rectangle around its center.
left
X-coordinate of the upper left corner of the rectangle.
top
Y-coordinate of the upper left corner of the rectangle.
right
X-coordinate of the bottom right corner of the rectangle.
bottom
Y-coordinate of the bottom right corner of the rectangle.
rotation
Rotation angle in degrees of the rectangle with its center as point of rotation.
If the rotation angle does not equal zero, the left, top, right, and bottom coordinates are not the actual coordinates of the upper left and bottom right corner of the rectangle. Instead these coordinates are a position, if the rotation angle equals zero.
coordinate system
Input that specifies the coordinate system to use.
reference system
Cluster containing origin, angle (deg), and axis reference.
origin
Point cluster that specifies the origin of the base-reference coordinate system.
x
X-coordinate of the center of the circle.
y
Y-coordinate of the center of the circle.
angle (deg)
Angle that the base-reference coordinate system makes with the image coordinate system.
axis reference
Element defined as direct or indirect.
measurement system
Cluster containing origin, angle (deg), and axis reference.
origin
Point cluster that specifies the origin of the base-reference coordinate system.
x
X-coordinate of the center of the circle.
y
Y-coordinate of the center of the circle.
angle (deg)
Angle that the base-reference coordinate system makes with the image coordinate system.
axis reference
Element defined as direct or indirect.
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.
Default: No error
options
Cluster defining the parameters of the template location algorithm and the information that is overlaid on the result image.
algorithm
Pattern matching algorithm used to find the template information.
all learns the template using all of the algorithms.
| Name | Value | Description |
|---|---|---|
| all | 0 | Uses all of the algorithms, one after the other. |
| low discrepancy sampling | 1 | Uses a low discrepancy sampling algorithm. This algorithm extracts the most significant information to represent an image. If the template contains large regions of similar grayscale information, a wide aspect ratio, or is very small, use one of the pyramidal matching algorithms instead. |
| grayscale value pyramid | 2 | Uses a grayscale value pyramid algorithm. This algorithm uses normalized gray values as features, and is useful when the template does not contain structured information, but has intricate textures for dense edges. |
| gradients pyramid | 3 | Uses a gradient pyramid algorithm. This algorithm uses filtered edge pixels as features. This algorithm is more resistant to occlusion and intensity changes compared to the grayscale value pyramid, and is often being faster because of a smaller amount of data. However, the strength and reliability of edges reduces at very low resolutions this method requires the user to sometimes work at higher resolutions compared to the gray value method. |
number of matches requested
Number of valid matches expected.
minimum match score
Smallest score a match must have to be considered valid.
subpixel accuracy
Boolean that specifies if the match results should be returned with subpixel accuracy.
rotation angle ranges
Array of angle ranges where each range specifies how much the template pattern rotates in the image.
Each range is specified by a start angle and an end angle, both of which are expressed in degrees.
show search area
Boolean that pecifies if the centers and bounding rectangles of the patterns found are overlaid on the result image.
show result
Boolean that specifies if the centers and bounding boxes of the patterns found are overlaid on the result image.
number of matches
Number of template matches found in the inspection image based on the input settings.
image out
Reference to the destination image.
The search area and/or the result of the measurement can be overlaid on the image according to the settings.
matches (pixel)
Array of match clusters, in pixel coordinates.
Position
Point-coordinate cluster corresponding to the center of the template.
Angle
Rotation angle of the template in the source image at the current match location.
Scale
Change in percentage size of the matched template from the original template.
This parameter is not used for pattern matching and is always set to 1.
Score
Match results ranked on a scale of 0 to 1000, where 0 equals no match and 1000 equals a perfect match.
Bounding Box
Array of points that define the boundary of the template pattern in the image.
Connect this array directly to the Overlay Multiple Lines node to overlay the location of a match on the image.
matches (real-world)
Array of match clusters, in real-world coordinates.
Position
Point-coordinate cluster corresponding to the center of the template.
Angle
Rotation angle of the template in the source image at the current match location.
Scale
Change in percentage size of the matched template from the original template.
This parameter is not used for pattern matching and is always set to 1.
Score
Match results ranked on a scale of 0 to 1000, where 0 equals no match and 1000 equals a perfect match.
Bounding Box
Array of points that define the boundary of the template pattern in the image.
Connect this array directly to the Overlay Multiple Lines node to overlay the location of a match on the image.
coordinate system dup
Reference to the coordinate system.
reference system
Cluster containing origin, angle (deg), and axis reference.
origin
Point cluster that specifies the origin of the base-reference coordinate system.
x
X-coordinate of the center of the circle.
y
Y-coordinate of the center of the circle.
angle (deg)
Angle that the base-reference coordinate system makes with the image coordinate system.
axis reference
Reference to the axis defined as direct or indirect.
measurement system
Cluster containing origin, angle (deg), and axis reference.
origin
Point cluster that specifies the origin of the base-reference coordinate system.
x
X-coordinate of the center of the circle.
y
Y-coordinate of the center of the circle.
angle (deg)
Angle that the base-reference coordinate system makes with the image coordinate system.
axis reference
Reference to the axis defined as direct or indirect.
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.
elapsed time
Duration of the search, in milliseconds.
Where This Node Can Run:
Desktop OS: Windows
FPGA: Not supported
Web Server: Not supported in VIs that run in a web application