Methods for non-contact monitoring of three-dimensional global landslide deformation with millimeter-level accuracy

A method for non-contact monitoring of three-dimensional global landslide deformation with millimeter-level accuracy, comprising:

• S1:
• acquiring two phases of three-dimensional surface deformation point cloud data for deformation interpretation, and extracting global point cloud features;
• S2:
• performing optimization using a Bayesian optimization algorithm based on the global point cloud features and a trained neural network model to obtain an optimal initial calculation point spacing, a minimum point cloud search radius, a maximum correspondence point search distance, a point count threshold of point cloud, and a root mean square error (RMSE) threshold;
• S3:
• obtaining initial calculation points based on the optimal initial calculation point spacing, dividing to obtain initial point cloud blocks, performing preliminary registration using an average domain vector algorithm to obtain an initial transformation matrix, and decomposing the initial transformation matrix to obtain a translation vector and a rotation matrix;
• S4:
• reducing a calculation point spacing to obtain new calculation points, and performing weighted averaging on a rotation vector and the translation vector of previous calculation points adjacent to the new calculation points using inverse distance weighting to obtain initial transformation parameters of the new calculation points;
• S5:
• rotating and translating the initial point cloud blocks to new positions based on the initial transformation parameters of the new calculation points, performing re-registration to obtain a new transformation matrix, and decomposing the new transformation matrix to obtain a new translation vector and a new rotation matrix;
• S6:
• repeating the S4 and S5, when a displacement of a current calculation point after certain registration is less than a specified threshold, assuming that a current calculation point spacing is d, determining calculation as completed when the displacement of the current calculation point is within a range of d/2, and when reducing the calculation point spacing next time, a region where the calculation point is located not taking the new calculation points but directly using the previous calculation points;
• and when the calculation point spacing is reduced to the specified threshold, determining calculation as completed after current calculation ends;
• after the S6, the method further comprising:
• interpreting to obtain a translation vector {right arrow over (t)}n corresponding to the calculation points based on all calculation points and corresponding transformation matrices in final calculation, and superimposing the translation vector {right arrow over (t)}n with an initial translation vector {right arrow over (t)}n−1 of the current calculation to obtain a total translation vector {right arrow over (t)}total of the calculation points;
• t
• →
• total
• =
• t
• →
• n
• -
• 1
• +
• t
• →
• n
• obtaining a global displacement and deformation field of a calculation region.