Abstract: An image based opto-electronic encoder for a joint, the encoder having a reading head for the first part of the joint and an optical system, comprising a ball lens for the second part of the joint. The ball lens has a front surface transparent for measuring light and an at least partially reflective, structured back surface. The ball lens has—with respect to the measuring light—a refractive index of at least approximately two or an equal radially varying refractive index, such that a bundle of measuring light rays reflected inside the ball lens from a point of the back surface of the ball lens forms at least approximately a parallel bundle after getting refracted at the front surface of the ball lens. The reading head and the ball lens are rotatable relative to each other in at least two degrees of freedom.

Abstract: A Coordinate Measuring Machine (CMM) system comprising a CMM, a rotary table, and a rotation arrangement, wherein the CMM system is configured to be calibrated by determining the 6 dof pose of a jig, and to a method for calibrating. The jig may be mounted such that a current pose of the jig is associated with a current pose of the rotary table with respect to the CMM. The rotary table may be moved into multiple poses, and the 6 dof pose of the jig is measured for each of the multiple poses of the rotary table. An error map is generated, based on the angles associated with the poses of the rotary table, and is used to generate a coordinate transformation from the CMM coordinate system to the part coordinate system, which is associated with the rotary table, based on the error map.

Abstract: An image based opto-electronic encoder for a joint, the encoder having a reading head for the first part of the joint and an optical system, comprising a ball lens for the second part of the joint. The ball lens has a front surface transparent for measuring light and an at least partially reflective, structured back surface. The ball lens has -with respect to the measuring light- a refractive index of at least approximately two or an equal radially varying refractive index, such that a bundle of measuring light rays reflected inside the ball lens from a point of the back surface of the ball lens forms at least approximately a parallel bundle after getting refracted at the front surface of the ball lens. The reading head and the ball lens are rotatable relative to each other in at least two degrees of freedom.

Abstract: A Coordinate Measuring Machine (CMM) system comprising a CMM, a rotary table, and a rotation arrangement, wherein the CMM system is configured to be calibrated by determining the 6 dof pose of a jig, and to a method for calibrating. The jig may be mounted such that a current pose of the jig is associated with a current pose of the rotary table with respect to the CMM. The rotary table may be moved into multiple poses, and the 6 dof pose of the jig is measured for each of the multiple poses of the rotary table. An error map is generated, based on the angles associated with the poses of the rotary table, and is used to generate a coordinate transformation from the CMM coordinate system to the part coordinate system, which is associated with the rotary table, based on the error map.