Surface Alignment
Description
This Step aligns the input surface data to a template in the XOY plane via translation and rotation, ensuring the consistency between the two.
Workflow
The process of configuring this Step is shown below:
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Configure the input. Connect the ports manually or select the input(s) under Input in the parameter configuration panel.
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Make and select a template. For more information on how to make a template, refer to 2D Template Editor.
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Determine whether to enable Use intensity image and Use feature region based on the actual scenario.
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Set Matching Settings.
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Select the desired output(s) under Output.
Input Description
| Input item | Description | ||
|---|---|---|---|
Surface Data |
Surface data used for alignment with the template. |
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Alignment parameter group |
Used to adjust the feature region’s pose in sync with the target object’s pose changes.
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Parameter Description
| Parameter | Description |
|---|---|
Use intensity image |
Determines whether to use the intensity image for template matching. If selected, you must use an intensity image when creating the template; otherwise, the matching will fail. Unchecked by default. When this option is cleared, the Step uses the depth map in the surface data for matching. |
Use Feature Region |
Restricts the matching algorithm to work only within the specified region, improving matching speed and reducing false matches. For more information on how to set and adjust the feature region, see Feature Region. If an alignment parameter group is provided, the Step dynamically adjusts the position and angle of the feature region based on pose changes of the target object during execution. |
Template Settings
| Parameter | Description | ||
|---|---|---|---|
Select template |
This parameter sets the matching template. Click Open the editor to open 2D template editor, where you can edit the template for alignment. After setting and saving the template, click ▼ and select the template in the drop-down menu. For instructions on how to use the editor, refer to 2D Template Editor.
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Matching Settings
Frequently Used Parameters
| Parameter | Description |
|---|---|
Edge Polarity Sensitive |
This parameter controls whether edge polarity must match the template. The polarity indicates the direction of intensity changes along the edges, e.g., light-to-dark or dark-to-light. If there is not a large disparity in the data acquisition scenarios, enable this option to ensure matching accuracy. If there is a large disparity, disable this option to enhance the matching generalization ability. Enabled by default. |
Min Matching Score |
This parameter is used to determine whether a matching result is valid. Any result whose score is below this value will be discarded. Default setting: 50.0 |
Advanced Parameters
| Parameter | Description | ||
|---|---|---|---|
Valid Matching Threshold |
In the target image, points with gradient magnitudes greater than or equal to this threshold are considered valid edge points and participate in matching score calculation. Default value: 10 |
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Min Valid Match Ratio |
The minimum ratio of valid matched edge points to the total number of edge points in the template. Default value: 50% |
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Search Radius |
The radius of the circular search area for finding corresponding matching points of each template feature point in the target image during pose refinement. Default value: 8
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Max Overlap Ratio |
Used to filter out duplicate matching results. If there is an overlap between two matching results and the overlap ratio exceeds this value, only the result with the higher matching score will be retained. Default value: 50% |
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Padding Ratio |
Specifies the ratio of allowed padded size to template size when the target object may be partially outside the image. Padding can recover edge matches that would otherwise fail, but generally increases computation.
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Output Description
Select the output item(s) to add the output port(s) to the Step, and the corresponding data will be output after the Step is run. You can select the output according to the actual measurement requirements.
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If you select an expandable output item, you must expand it by clicking ▶, and then set the Lower Limit and Upper Limit values to determine the acceptable range. If the output value falls within the acceptable range, the measurement item is judged as passing (OK), or else it is judged as failing (NG). |
| Output item | Description | ||
|---|---|---|---|
Aligned surface data |
The surface data after alignment. |
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Matching score |
Used for evaluating the quality of the matching result. |
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Alignment parameter group |
Provides the translation and rotation parameters required to align the matched object with the template.
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Troubleshooting
See Error Code List for common error messages and solutions.