Development of computer vision measurement system for magnetic head pitch and roll angles of the single head arm assembly in hard disk driver

The researches on the high efficient, safe and accurate measurement system of magnetic head pitch and roll angles for the HAA in HDD are relatively lack now. In this paper, the perspective projection transformation of the magnetic head object point in the reference image plane was expressed by using the rotary tensor transformation matrix, and the principle for projection deviation angle between the actual object point and ideal object point was derived. Thus, the measurement system hardware with two sets of two-dimensional platforms and CCD camera for measuring magnetic head spatial pitch and roll angles was established, and based on Wit7.0 toolkit and using Microsoft VB6.0 programming language, the measurement system software were obtained by secondary development. Also, the stable performance of the measurement system based on computer vision was demonstrated in the practical application.