MESHLAB ALIGN POINT CLOUDS SOFTWARE

Max iteration number: the maximum number of iterations that the software will performĪfter clicking Process, the software starts to automatically calculate, save the project as an ALN file (Align Project), and then open it with a text editor, you can see that each point cloud in the Align file has a rotation matrix representing its position and posture.Target distance (equivalent to mean square error mse): an average alignment error value that the software will try to obtain from the process.Once the initial alignements are complete, drop it down to 1mm to'fine tune' A value of 5 or 10 (in millimeters) is usually a good start. Typically for a manually aligned object you want this to be large enough to encompass your'point picking' error. Minimal starting distance: this ignores any samples that are outside of this range.A small sample typically works quiet well.

You do not want to make this number too big.

Sample Number: this is the number of samples it pulls from each mesh to compare to the other meshes.

If we don't check it, there will be a scaling factor in the final transformation matrix. If our two point clouds have the same size, then we must check the Rigid matching selection. Pay attention to the default parameters in Param ICP Default and modify them as needed. After the initial registration, we will perform ICP registration. Later, you will find that the two point clouds are basically overlapped, and an asterisk appears before the name of the second point cloud. Double-click the left mouse button to select, hold down Ctrl and double-click the left button to eliminate the selection. Select at least 4 pairs of points and click OK to confirm. Manually select matching points on the two point clouds. Then select another point cloud and click Point Based Glueing. After the selection, an asterisk will appear in front of the point cloud name. Here, use the original point cloud without translation and rotation as the reference, and then click Glue Here Mesh. Then click the Align button on the toolbar to perform registration, and an Align Tool dialog box will pop up. Import these two files into MeshLab, and you can see two point clouds after the rendering mode is selected as point, as shown in the figure below. The transformation matrix T corresponding to this transformation is: Then the monkey head is translated and rotated in Blender to another position, where it is translated 2 units along the XYZ axis (keyboard commands in Blender: GX2, GY2, GZ2), and then rotated -45° around the Z axis (RZ-45), and finally output it as a PLY file. PLY is a commonly used in the field of graphics research. It allows files to be stored in ASCII format or in binary form. Next, output it as a file in PLY format (PLY file format is a set of three-dimensional mesh model data format developed by Stanford University. First press the X key in Blender to delete the default cube, then press Shift+A to create a monkey head suzanne (Suzanne is Blender's alternative to more common test models such as the Utah Teapot and the Stanford Bunny), and then add a modifier, Subdivision Surface set the Render to 1 and click Apply. The open source 3D modeling software Blender is used here. For verification, you need to create two point clouds with mismatched positions and poses.

MESHLAB ALIGN POINT CLOUDS REGISTRATION

Let's try the point cloud registration function in MeshLab. export: PLY, STL, OFF, OBJ, 3DS, COLLADA, VRML, DXF, GTS, U3D, IDTF, X3D.import: PLY, STL, OFF, OBJ, 3DS, COLLADA, PTX, V3D, PTS, APTS, XYZ, GTS, TRI, ASC, X3D, X3DV, VRML, ALN.

Meshlab align point clouds