Fig. 1. Schematic diagram of camera depth of field in composite surface measurement system

Fig. 2. Principle of knife-edge method

Fig. 3. Diagram of secondary defocusing method

Fig. 4. Flow chart of system parameter selection strategy

Fig. 5. Composite surface measurement system model based on fringe projection and direct phase measure deflectometry

Fig. 6. Hardware setup of the composite surface measurement system

Fig. 7. Defocus quantification method simulation. (a) Analysis of results of simulated edge method; (b) Estimation of defocus amount

Fig. 8. Defocus calibration. (a) Edge defocus value; (b) Defocus values fitted to multiple positions using plane fitting

Fig. 9. Analysis of phase error model. (a) Simulation of the phase error; (b) Experimental and simulation error comparison

Fig. 10. Optimal defocus analysis of the LCD-reference surface. (a) Optimal defocusing selection; (b) Defocusing range of LCD

Fig. 11. Reference plane spectrum analysis. (a) Binary at the front end; (b) Binary at the back end; (c) Modulated binary at the front end

Fig. 12. Composite surfaces object. (a) Computer identification; (b) Ring step

Fig. 13. Optimal defocus analysis of the LCD-measured step. (a) Optimal defocusing selection; (b) Defocusing amount for LCD component

Fig. 14. Phase unwrapping and comparison of step. (a) Uncompensated binary fringes; (b) Sinusoidal fringes; (c) Compensated binary fringes; (d) Sinusoidal fringes; (e) Absolute phase of (a); (f) Absolute phase of (b); (g) Absolute phase of (c); (h) Absolute phase of (d)

Fig. 15. Comparison of three-dimensional topography for specular components. (a) Uncompensated binary fringes; (b) Sinusoidal fringes; (c) Compensated binary fringes

Fig. 16. Results of three-dimensional surface topography reconstruction for composite objects. (a) Surface topography of computer identification; (b) Reconstructed depth of step