Linear Facility Extraction

Description

• Template selection and editing: Including template selection, template point cloud, key point editing and template saving.
• Strip object extraction: Draw a path based on the selected template, and then perform detection and extraction use manual or semi- automatic methods.

Template editing and selection operations

• Template View: The template view is located on the left side, used to display the template point cloud and key points for the current application.

• Template Selection:When the function is activated, the program automatically loads the template file into the template selection box. Users choose a template that matches the detected object (paying attention to the template point cloud orientation). After setting up the template, the software automatically copies the template file to the user data folder (AppData), and subsequently reads template data from this folder.

• Edit: Enable and disable template editing. When template editing is enabled, the detection function button becomes unavailable. It is restored after closing template editing.

• Create Template: The interaction logic is the same as the profile. Draw a template point cloud with an appropriate thickness perpendicular to the direction of the strip-shaped object. The drawing result will be displayed in the left template view.

• Profile Settings: Used to set the point cloud category and size within the profile, achieving precise control over the template point cloud.

  • Class: Set the category points for generating the template.
  • Thickness: Display the length in the vertical direction of the profile. When checked, it indicates that the thickness is locked.
  • Height: Profile height, with the line as the starting height, and equal portions above and below set height.
  • Width: Draw the horizontal distance between two points.
    

Pay special attention to the adjustment of 'Height,' for example, with railings. When ground points are not within the profile range, adjusting the 'Height' ensures that ground points fall within the profile, ensuring effective extraction.

• Add key points: After creating the template point cloud, select key points on the template point cloud to serve as the starting points for the growth of vector lines for strip-shaped objects.

• Selection key points: Used for key point editing. After selection, use the 'Delete' key to remove key points. Drag with a long left-click to modify the position of the key point.

• Save Template: Temporarily drawn templates are placed in the 'Temporary' section. After saving the template, it can be used in the next extraction.

• Delete Template: Delete the current non-'Temporary' template.

Procedure:

1.Click the Linear Facility Extractionbutton in the road facilities panel to enter edit mode.

2.Click the Start Editbutton to enter template editing mode.

3.Click the Draw Templatebutton, select the profile to draw in the point cloud, and add Key Point 1 and Key Point 2.

4.Click the Save Templatebutton, a dialog box will appear for saving the template. Set the file name and click 'OK'.

5.Click the Finish Editingbutton to close the editing.

Strip Feature Extraction Operation

• Result View: The result view is located on the right side, used to display the results of each extraction, and supports adjustment of key points in the extraction results.

• Layer Selection: Select the result saving layer (line layer).

• Draw a straight line: After activation, draw a straight line in 3D view along the strip-shaped object. The first segment of the line is used to provide the initial detection direction. Extraction starts from the second point, and the extraction result is displayed in the right result view.

• Draw an arc: Draw an arc path, suitable for curved objects. Supports the 'S' shortcut key to switch between 'Line' and 'Arc' shapes, right-click to go back to the previous point.

• Automatic Detection: After completing the drawing of a line segment path (two points), automatic detection can be initiated every 1.5 seconds. If the detection results do not meet the requirements, you can use the spacebar to stop detection, use the right mouse button to backtrack to points that do not meet the requirements, or manually adjust the extraction point positions in the result view. Then, press the spacebar again to continue forward detection. After detection is complete, press Enter to finish.

Procedure:

1.In the left dropdown box for strip feature extraction, select a template. In the right layer dropdown, choose the layer you need.

2.Click the Linebutton, draw the vector line of the object to be extracted in the point cloud. Right-click to undo a node. Click the automatic detectionbutton for automated detection.

You can also choose the Arcbutton according to your actual needs.

3.Click the Stopbutton to end automatic detection. Double-click with the left mouse button to finish editing.

Strip Feature Extraction Results

Important Notes

• Profile point cloud: First, try to ensure that the size and geometric features of the template point cloud are similar to the extraction point cloud. Second, try to include ground points.

• Template Switching: During the extraction process, you can switch templates for continuous detection, but the number of key points in the two templates must be the same.

• Category and Profile Size: Used to adjust the point cloud involved in the extraction.

• Step: Set the automatic detection forward step length. A shorter step length results in finer detection, and it should be reduced at turns.

• Wait Time: Wait time between automatic detections of two frames, used for manual adjustment of extraction results.