Dimensional X-ray CT has attracted production industry due to its nature  enabling not only external dimensional measurement but also internal dimensional measurement which has been difficult for pre-existing dimensional measurement instruments. However, because the reconstruction process of three dimensional volume image may be affected by various kinds of error sources of the hardware and also the software, performance evaluation of dimensional X-ray CT has become one of the major issues , especially for X-ray CT system with higher energy such as several MeV. Resolution performance of high energy X-ray CT was evaluated by using a series of phantoms which equip regular line-and-space structures with various pitch sizes down to 100 micrometer. These phantoms were prototyped in the identical pitch sizes with three different materials. These phantoms were practically measured by a high energy X-ray CT. Results and perspective of the resolution performance is presented.
This paper describes the automatic calibration system for an angle encode which is installed at the AIST (National Institute of Advanced Industrial Science and Technology). The system uses the Equal-Division-Averaged (EDA) method that is one kind of the self-checking method. This system has great performance of the calibration with small uncertainty. In this paper we try to explain the factor of uncertainty of this system. The dominant uncertainty factor is the eccentricity of shaft between the system and an external rotary encoder. The influence from other factors is very small about 0.01" or less.
This paper describes the automatic calibration system for angle encoders which is installed at the AIST. The system uses the Equal-Division-Averaged (EDA) method that is one kind of the self-checking method. Both of the reference standard and the object angle encoders are calibrated at the same time against all encoders graduations within only one hour. The resolution and an uncertainty are 0.001 inch and approximately +/- 0.05 inch, respectively. This equal- division-averaged method is hoped to become the national standard method for the calibration of angle encoders.