Abstract: A measurement X-ray CT apparatus calibrates a geometrical positional relationship between a focus of an X-ray source, an X-ray detector, and a rotation center of a rotating table in advance. The measurement X-ray CT apparatus then obtains projection images by irradiating the object to be measured with X-rays to perform a CT scan, and generates a three-dimensional image of the object to be measured by CT reconstruction of the projection images. The measurement X-ray CT apparatus further includes a reference frame that is made of a material and has a structure less susceptible to environmental changes, and sensors that are located on the reference frame and intended to successively obtain calibration values of the geometrical positional relationship between the focus of the X-ray source and the X-ray detector during the CT scan. The calibration values are used as parameters of the CT reconstruction.

Abstract: A measurement X-ray CT apparatus calibrates a geometrical positional relationship between a focus of an X-ray source, an X-ray detector, and a rotation center of a rotating table in advance. The measurement X-ray CT apparatus then obtains projection images by irradiating the object to be measured with X-rays to perform a CT scan, and generates a three-dimensional image of the object to be measured by CT reconstruction of the projection images. The measurement X-ray CT apparatus further includes a reference frame that is made of a material and has a structure less susceptible to environmental changes, and sensors that are located on the reference frame and intended to successively obtain calibration values of the geometrical positional relationship between the focus of the X-ray source and the X-ray detector during the CT scan. The calibration values are used as parameters of the CT reconstruction.

Abstract: A non-contact surface roughness-measuring machine is provided which can avoid damage caused by collision with a workpiece and set a non-contact surface roughness probe at an appropriate position relative to a measurement surface of the workpiece. A non-contact surface roughness probe and a touch-signal probe are attached at a tip end of an arm of a coordinate measuring machine. A stylus of the touch-signal probe is protruded relative to a detection surface of the non-contact surface roughness probe, in which the protrusion amount is within an optimum distance of the non-contact surface roughness probe relative to the measurement surface. When the probes are brought close to the workpiece and the touch-signal probe detects contact, the non-contact surface roughness probe is set within the optimum distance relative to the workpiece.