Research On Pupil Shape Problem In Self-referencing Interferemeter Wavefront Detection

Based on the principle of pinhole diffraction, the self-referencing interferometerwavefront sensor obtains idea standard wave surface and then get directly the measuredwavefront information by using phase reconstruction technology. All kinds ofinterferometry always need to accurately determine the effective data area ofinterferograms. At the same time, the operation of position registration will also be neededto the simultaneous phase-shifting interferograms. In addition, the performance of existingwavefront sensors will decline while they are applied to wavefront detection of irregularpupil beam. Therefore, the paper will also study the wavefront detection of different pupilshapes, which is based on self-referencing interferometer wavefront sensor.This paper firstly develops a position registration method applied to circular domainsimultaneous phase-shifting interferograms, which based on statistical analysis ideaincluding variance analysis, threshold segmentation and improved Hough transform. Withthis method the position parameters and the effective data area of each frame ofinterferogram can be obtained. With numerical simulation the accuracy of this methodreaches to0.5pixels while the radius of edge is greater than64pixels. Moreover, we builta self-referencing simultaneous phase-shifting interferometer to validate experimentally ofthe proposed method. The experimental results show that, this method is accurate andreliable, and it can assure the reconstructed accuracy of wavefront phase, also holds abetter ability ofresisting environment, convenience and practicability as well.Additionally, this paper takes the central obscuration light beam as an example, thenthrough numerical simulation studies the reference wave after pinhole filter, and hence theoptimal pinhole size is obtained for the central obscuration pupil. The simulated resultsshow that the self-referencing interferometer wavefront sensor may be applied in thewavefront detection of arbitrary pupil shapes light beam. Also, we has studied the effectivedata area determination and wavefront reconstruction of central obscurationinterferograms.The proposed method about effective data area determination and position registrationholds an extremely significant application value in the pattern preprocessing. The studied achievement about central obscuration pupil shape provides a valuable idea to study thewavefront detection of arbitrary pupil shapes light beam, and will also establish thecorresponding studied foundation for the further research on the related fields.