Table Of Contents
Detect Shapes (Detect Lines) (G Dataflow)
Searches for lines in an image.
ROI descriptor
Rectangle or rotated rectangle within which to detect shapes.
Global Rectangle
Coordinates of the bounding rectangle.
Contours
Individual shapes that define an ROI.
ID
Object specifying if contour is the external or internal edge of an ROI.
Type
Shape type of the contour.
Coordinates
Relative position of the contour.
image in
Reference to the searched image.
line length range
Lengths of lines to detect.
Min Length
Minimum length of the described line.
Max Length
Maximum length of the described line.
curve extraction options
Information about how curves are extracted from the inspection image during the match phase.
Extraction Mode
Input that specifies how the node identifies curves in the image.
| Name | Value | Description |
|---|---|---|
| Normal | 0 |
(Default) Select if you want the node to make no assumptions about the uniformity of objects in the image or the image background. |
| Uniform Regions | 1 |
Select if you want the node to assume that either the objects in the image or the image background consist of uniform pixel values. This allows the node to more accurately calculate the external curves of the objects. |
Edge Threshold
Minimum contrast a seed point must have for it to begin a curve.
Valid values range from 1 to 255.
Default: 75
Edge Filter Size
Width of the edge filter that the node uses to identify curves in the image.
| Name | Value | Description |
|---|---|---|
| Fine | 0 |
Sets to fine edge filter size. |
| Normal | 1 |
(Default) Sets to normal edge filter size. |
| Contour Tracing | 2 |
Sets to contour tracing edge filter size, which provides the best results for contour extraction but increases the time required to process the image. |
Min Length
Length, in pixels, of the smallest curve that you want the node to identify.
The node ignores any curves that have a length less than this value.
Default: 25
Row Search Step Size
Distance, in the y direction, between the image rows that the algorithm inspects for curve seed points.
Valid values range from 1 to 255.
Default: 15
Col Search Step Size
Distance, in the x direction, between the image columns that the algorithm inspects for curve seed points.
Valid values range from 1 to 255.
Default: 15
Max Endpoint Gap
Maximum gap, in pixels, between the endpoints of a curve that the node identifies as a closed curve.
If the gap is larger than this value, the node identifies the curve as an open curve.
Default: 10
Closed
match options
Match options used when detecting shapes.
Rotation
Boolean input specifyomg whether or not to search for rotated versions of the shape.
Scale
Boolean that specifies whether or not to search for scaled versions of the shape.
occlusion
Boolean that specifies whether or not to search for occluded versions of the shape.
Range Settings
Array that specifies the allowable ranges for rotation and scale.
Match Constraints
Match option whose values you want to constrain by the given range.
| Name | Value | Description |
|---|---|---|
| Rotation Angle (degrees) | 0 |
Set a range for this option to specify the angles at which you expect the node to find template matches in the inspection image. The node ignores this range if the Rotation is not enabled. |
| Scale Factor (%) | 1 |
Set a range for this option to specify the sizes at which you expect the node to find template matches in the inspection image. The size is expressed as the following percentage: the size of the match divided by size of the template image, multiplied by 100. The node ignores this range if the Scale is not enabled. |
| Occlusion (%) | 2 |
Set a range for this option to specify the amount of occlusion you expect for a match in the inspection image. Matches that have up to 50% occlusion are accurately detected. The node ignores this range if the Occlusion is not enabled. |
Min
Minimum value of the range for a given match constraint.
Max
Maximum value of the range for a given match constraint.
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
minimum match score
Minimum score a returned shape can have.
image out
Reference to the image input.
lines
Array of line clusters that describe each found line.
Start Point
Starting point of the line.
End Point
Ending point of the line.
Length
Length of the line measured in pixels from the start point to the end point.
Angle
Orientation of the line with respect to the horizontal.
Score
Score of the found line. Values range from 0 to 1000, where 1000 represents a perfect match.
number of lines
Number of matches found.
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.
Where This Node Can Run:
Desktop OS: Windows
FPGA: Not supported
Web Server: Not supported in VIs that run in a web application