Tunnel Point Cloud Unrolling

Tunnel point cloud unrolling is a key technology that projects 3D tunnel point clouds onto a 2D plane along the centerline, transforming complex spatial geometric problems into intuitive planar analysis problems.

The unrolled point cloud is presented in a (Mileage, Arc Length, Depth) coordinate system, retaining original attributes such as intensity and color. It supports applications such as tunnel lining defect identification and convergence deformation monitoring.

Supports two unrolling methods: Segmented Projection and Cylindrical Projection, and provides a tunnel centerline extraction tool.

• Define Projection Segments
• Centerline Extraction
• Unrolling

Steps

Select the appropriate unrolling workflow based on the tunnel contour shape.

Cylindrical Projection Unrolling

Suitable for tunnel contours with a single circular arc shape.

1. Extract the tunnel centerline using the Circle Fitting mode in Centerline Extraction;

2. Select the Cylindrical Projection method in Unrolling, define the tunnel radius, and complete the unrolling.

Segmented Projection Unrolling

Suitable for complex tunnel contours composed of non-single circular arcs.

1. Complete the tunnel contour line element definition in Define Projection Segments;

2. Extract the tunnel centerline using the Segmented Matching mode in Centerline Extraction;

3. Select the Segmented Projection method in Unrolling and use the defined projection segments to complete the unrolling.

Export TIFF

The unrolling result is a LiData format point cloud that retains original attribute information (intensity, color, etc.). If TIFF format image results are needed, run the Point Cloud Tools→Export→Convert to TIFF tool in the toolbox.