 | Find Straight Edge Controls |
Main Tab
The following controls are available on the Main tab.
| Control Name |
Description |
| Step Name |
Name to give the step. |
| Region of Interest |
The region of interest you want to use for the step. |
| Reposition Region of Interest |
When enabled, the step dynamically repositions the region of interest based on a coordinate system you built in a previous step. |
| Reference Coordinate System |
Coordinate system to which you want to link the region of interest. |
Settings Tab
The following controls are available on the Settings tab.
| Control Name |
Description |
| Direction |
Direction in which you want the search lines to look for a straight edge within the region of interest. The following options are available:
- Left to Right—Searches for edges from left to right.
- Right to Left—Searches for edges from right to left.
- Top to Bottom—Searches for edges from top to bottom.
- Bottom to Top—Searches for edges from bottom to top.
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| Edge Polarity |
Specifies the pixel intensity transitions to use to determine edges. The following options are available:
- All Edges—Finds edges characterized by dark-to-bright and bright-to-dark pixel intensity transitions.
- Dark to Bright Only—Finds only those edges characterized by dark-to-bright pixel intensity transitions along the direction of the search line.
- Bright to Dark Only—Finds only those edges characterized by bright-to-dark pixel intensity transitions along the direction of the search line.
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| Look For |
Specifies the type of edges to find in the image. The following options are available:
- First Edge—Finds only the first edge of the specified polarity along each independent search line based on the direction of the search line.
- Best Edge—Finds only the best edge of the specified polarity along each independent search line.
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| Auto Setup |
When enabled, the step automatically locates the strongest edge in the region of interest and returns the parameters it used to find the edge. |
| Minimum Edge Strength |
Minimum difference in the intensity values between the edge and its surroundings. |
| Kernel Size |
Specifies the size of the edge detection kernel. |
| Projection Width |
Specifies the number of pixels averaged perpendicular to the search direction to compute the edge profile strength at each point along the region of interest. |
| Gap |
Specifies the size, in pixels, of the space between the search lines. |
| Edge Strength Profile |
Graphical representation of the edge contrast along the search line specified by the Search Line Index. |
| Search Line Index |
Specifies the index of the search line represented in the Edge Strength Profile. |
Advanced Tab
The following controls are available on the Advanced tab.
| Control Name |
Description |
| Edge Strength Profile |
A graphical representation of the edge contrast along the specified search line. The yellow line indicates the location of the found edge. |
| Search Line Index |
Specifies the index of the search line represented in the Edge Strength Profile. |
| Edge Points Found |
Displays information about the edge points found along all the search lines in the ROI. The following information is displayed for each edge:
- Strength—Strength of the edge. Values range from 0 to 1000 with larger values indicating a stronger edge.
- STR—Signal to threshold ratio for the edge, expressed in decibels.
- TNR—Threshold to noise ratio for the edge, expressed in decibels.
- SNR—Signal to noise ratio for the edge, expressed in decibels.
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Limits Tab
The following controls are available on the Limits tab.
| Control Name |
Description |
| Minimum Angle |
Minimum counterclockwise angle at which the edge can be located from a line perpendicular to the search direction. |
| Maximum Angle |
Maximum counterclockwise angle at which the edge can be located from a line perpendicular to the search direction. |
| Maximum Deviation |
Maximum average error between found edge points and the fitted straight line. |
| Minimum Short Distance |
Minimum distance allowed for the shorter of the following distances:
- The distance between the start point of the first search line and the intersection of the fitted line and the first search line.
- The distance between the start point of the last search line and the intersection of the fitted line and the last search line.
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| Maximum Long Distance |
Maximum distance allowed for the longer of the following distances:
- The distance between the start point of the first search line and the intersection of the fitted line and the first search line.
- The distance between the start point of the last search line and the intersection of the fitted line and the last search line.
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| Step Results |
Displays information about the straight edge found in the image.
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Note When you calibrate the image using a Calibrate Image step, X and Y are returned in the calibration unit you specified. |
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