Real scene three-dimensional model decryption method and system

The invention relates to a live-action three-dimensional model decryption method and system, and belongs to the field of three-dimensional model decryption, and the method comprises the steps: obtaining the plane coordinates of each node of a live-action three-dimensional model; determining a value domain range [xmin, xmax] and [ymin, ymax] of the plane coordinates; offset threshold values dx and dy and amplitude variables Sx and Sy of the sigmoid transformation function are determined; determining a relation coefficient kx and a relation coefficient ky; normalizing the plane coordinates of each node of the live-action three-dimensional model; determining plane coordinates after decryption; obtaining vertex coordinates of the live-action three-dimensional model; determining a vertex coordinate range [zmin, zmax] of the live-action three-dimensional model; obtaining a decryption scale v and an offset threshold dz; determining an amplitude variable a; determining a decryption function of the ground object heigh