LAUSR

Abstract. To evaluate the intermediate-frequency error of a precision optical surface, a method for more accurate separation and identification of the intermediate-frequency error is proposed. This method is based on the Hilbert spectrum and the instantaneous frequency separation method. Experimental results show that the intermediate-frequency error spectrum can be obtained using the method of instantaneous frequency separation based on the Hilbert spectrum. This method separates only the intermediate-frequency error component (0.03  mm  −  1  ≤  f  ≤  8.33  mm  −  1). Also, the method accurately identifies the nonqualified component distribution (at sampling points 200, 840, and 1000). Therefore, this algorithm is a useful guide for deterministic processing of optical components.