Wobbling limits the access speed and data storage density in hard disks. A method using optical triangulation of a projected linear array of light beams and time-delay integrated (TDI) imaging was explored to obtain the tilt distribution as the hard disk was rotated. This resulted in fringe image records. A fast-Fourier transform scheme was applied to process the fringe images for more accurate results using the technique. During experimental verification, the technique was shown to reveal the distribution of tilt of a typical hard disk rotating at 2000, 4000, and 6000 rpm.