A5103028630- Optical measurement and interference techniques
- Image Processing Techniques and Applications
- Advanced Measurement and Metrology Techniques
- Optical Systems and Laser Technology
- Surface Roughness and Optical Measurements
- Advanced X-ray Imaging Techniques
- Advanced Vision and Imaging
- Advanced Surface Polishing Techniques
Fudan University
2019-2021
In the phase measuring deflectometry, two groups of fringe patterns in orthogonal directions are usually applied to establish correspondences between pixel pairs on screen and camera. Usually, 16 phase-shifting with different spatial frequencies required order calculate absolute phases conventional temporal unwrapping algorithms. This requirement makes measurement inefficient not robust against environmental noise. this paper, an efficient retrieval strategy is developed, which requires only...
Off-axis deflectometry is widely applied in the measurement of specular surfaces. However, measuring accuracy depends on reliability geometrical calibration. Existing methods are inconvenient to be utilized due their disadvantages low efficiency and operational complexity. A simple calibration method proposed by applying a flat mirror with markers, only one image needs captured. compensation process introduced correct form error mirror. Experimental results show that re-projection errors...
The phase measuring deflectometry is a powerful method for complex optical surfaces, which captures the reflected fringe images associated with displaying screen and calculates normal vectors of surface under test (SUT) accordingly. captured are usually set conjugate to SUT, in turn makes defocused. As result, blurring effect caused by point spread function (PSF) off-axis catadioptric imaging system can bias solved phases. In order correct errors, light field constructed based on Fourier...
Phase measuring deflectometry is a powerful method of complex optical surfaces that captures the reflected fringe images associated with displaying screen and calculates normal vectors surface under test (SUT) accordingly. The captured are usually set conjugate to SUT, which in turn makes defocused. As result, blurring effect caused by defocus aberrations off-axis catadioptric imaging system can severely degrade phases solved from blurred images. In order correct phase errors, space-variant...
Deflectometry is a powerful measuring technique of complex optical surfaces. Usually series binary patterns or sinusoidal fringes are displayed on screen, and correspondences established between the screen camera points according to their gray levels phases. The image associated with pixel blurred due defocus aberrations off-axis imaging system, calculated location correspondence point will in turn be biased. space variant spread function catadioptric system analyzed based light field...
The phase measuring deflectometry is a powerful technique for the in-situ measurement of complex optics. Its accuracy comparable with conventional interferometry, but higher flexibility, stability and efficiency. three main challenges in deflectometric measurement, namely position-angle uncertainty calculating pixel correspondences, height-slope ambiguity specifying normal vectors, rank deficiency surface reconstruction are analyzed. Some significant error factors effective solutions...