(1) A simulation model to form the image of the objective surface on CRT proposed. Some kinds of test pieces were employed to the investigation : comparing their simulated images with observed figures on CRT, the both images coincide well each other. Consequently it is considered that the simplified model in the optical system for the simulation is practically usable. It enables to transform the coordinates of the objective surface to those on CRT.
(2) Based on the transformability of the coordinates above-mentioned, holographic interferometry with a large angle of incidence is incorporated to the measurement of form deviation of tooth flank of spur gears. The form deviation was expressed by the error surface defined on the plane of action, and was compared with the result obtained by the conventional measurement using contacting stylus. It is confirmed that the form deviation obtained by laser holographic interferometry has a comparable measuring, accuracy to that of the conventional m
(3)This method is applied to measurement of form deviation of helical gear. But there is a problem, that the existence of helix angle reduces the measurable region on a tooth flank in one shot and the area of this region decreases with increasing the helix angle and face width. To solve this problem, following procedure is proposed : The objective tooth flank is divided into some parts and the error surface for each divided zone of tooth flank is continuously concatenated on the plane of action of this gear. The error surface for the whole tooth flank is compared with the result of the conventional method. The measured results shows almost same accuracy as that of conventional method. A good characteristics of interferometry measurement are found, that a little chance of the error surface such as undulation in the form deviation of the objective tooth flank is clearly recongnized.