Point Cloud Edge Detection (Latitude-Longitude Scanning)

Functional Description

This operator extracts external contour edge points of the input point cloud on the XOY plane using a "scan line" method. First, it determines the range of the point cloud on the X and Y axes. Then, based on the set "Resolution" parameter, it divides the X-axis range into several intervals and finds the points with the maximum and minimum Y coordinates within each interval. Similarly, it divides the Y-axis range into intervals and finds the points with the maximum and minimum X coordinates within each interval. Finally, it merges all these found maximum/minimum points to serve as the extracted edge point cloud.

This method is mainly used to extract the outermost contour of the point cloud projection on the XOY plane, and is particularly suitable when the point cloud shape is approximately planar and its main projection surface is close to the XOY plane.

Usage Scenarios

  • Extracting Planar Contours: Obtain the external boundary of flat objects (such as plates, parts) on the XOY plane.

  • Obtaining 2D Envelopes: Get the approximate envelope range of the point cloud on a 2D plane.

  • Simplifying Edge Representation: For application scenarios with complex internal structures but only requiring the external contour.

Inputs and Outputs

Input Items

Pointcloud: Input point cloud or list of point clouds.

Output Items

Point cloud edge: A list of point clouds composed of the extracted edge points.

Parameter Description

This operator has two versions:

  • Point Cloud Edge Detection (Latitude-Longitude Scanning) : Processes point clouds without normal information.

  • Edge Extraction from Point Cloud with Normals(latitude and longitude scanning) : Processes point clouds with normal information.

Both have identical core functionality and parameters, only differing in the type of point cloud data they process.

Resolution

Parameter Description

The number of scan segments in the X-axis and Y-axis directions, determining the fineness of the scan.

Tuning Description

  • Increasing this value: Divides the X-axis and Y-axis ranges into more, smaller intervals, resulting in denser scanning and more densely extracted edge points. This can depict contour details more finely but increases computation.

  • Decreasing this value: Intervals become larger, scanning becomes coarser, and extracted edge points become sparser. Some contour details may be lost, but computation is faster. Needs to be adjusted based on the size, shape complexity, and desired edge point density of the point cloud.

Parameter Range

[0, 1000], Default: 100

Enable node

Parameter Description

Controls whether this operator performs calculations.

Tuning Description

  • Enabled (default): The operator functions normally.

  • Disabled: The operator performs no operations and directly outputs the input data.