The invention relates to a method and a device of mobile
augmented reality of an underground
engineering based on a mixed registration. The method comprises the following steps of: standardizing the inner parameters of a
video camera via two-step calibration method; designing a
landmark and regarding the
landmark as the initial base point of the coordinates; firstly realizing the
augmented reality registration based on the
landmark; binding the
video camera and the tracking sensor to form a
rigid body; reading the landmark based on the photogrammetric technology so as to calculate the offset between the center of the
video camera and the
rigid body of the tracking sensor; adding virtual information and mixing the information with the environmental scene; rendering and outputting so as to realize the
augmented reality; fixing a set
relay marker within the functional range of the tracking sensor; calculating out the relative coordinates of the
relay marker via marking point identification and
photogrammetry; calculating the offset value of the
relay marker and the initial base point; and converting the offset value into the coordinate extendable matrix to be loaded to the
system so as to realize the extension of the coordinate
system. Compared with the prior art, the invention has the advantages of low cost, no simple dependence on the landmark or tracking sensor, no need of a
global positioning system (GPS), high speed, convenience, high precision and the like, and creates conditions for enhancing the mobility of the reality technology.