A measurement device for measuring thread parameters of a threaded object and said measurement device defining a first spatial reference system comprising first co-ordinate axes (X, Y, Z), the threaded object defining a second spatial reference system comprising second co-ordinate axes (X', Y', Z'), comprising: • at least one computer controlled laser sensor (5', 5", 16), • a computer controlled mechanical moving system, on which said at least one sensor (5', 5", 16) is mounted, able to guide the at least one sensor (5', 5", 16) during scanning operations according to predefined scanning patterns, or trajectories, along which measurement points are selected such that a matrix that describes the quadratic form has maximum rank, when values corresponding to these measurement points are inserted in the matrix, • means to synchronize output signals of the at least one sensor (5', 5", 16) with spatial positions of the mechanical system, and computer means to calculate said matrix that describes the quadratic form thereby representing the threaded object in the first spatial reference system, thus providing a relationship between the first spatial reference system and second spatial reference system, and to control the at least one sensor (5', 5", 16) in the scanning operations, to produce computer images of thread shape of the scanned object, to store the images and to analyze the computer images to obtain quantitative information about thread characteristics, in particular taper, seal diameter and ovality, run-in, run-out, thread diameter, pitch along multiple generatrices of the tube, and step height, • an electronic circuit connecting the computer to the mechanical moving system and to the at least one laser sensor (5', 5", 16). • at least one computer controlled laser sensor (5', 5", 16), • a computer controlled mechanical moving system, on which said at least one sensor (5', 5", 16) is mounted, able to guide the at least one sensor (5', 5", 16) during scanning operations according to predefined scanning patterns, or trajectories, along which measurement points are selected such that a matrix that describes the quadratic form has maximum rank, when values corresponding to these measurement points are inserted in the matrix, • means to synchronize output signals of the at least one sensor (5', 5", 16) with spatial positions of the mechanical system, and computer means to calculate said matrix that describes the quadratic form thereby representing the threaded object in the first spatial reference system, thus providing a relationship between the first spatial reference system and second spatial reference system, and to control the at least one sensor (5', 5", 16) in the scanning operations, to produce computer images of thread shape of the scanned object, to store the images and to analyze the computer images to obtain quantitative information about thread characteristics, in particular taper, seal diameter and ovality, run-in, run-out, thread diameter, pitch along multiple generatrices of the tube, and step height, • an electronic circuit connecting the computer to the mechanical moving system and to the at least one laser sensor (5', 5", 16). <EOS>