3-D Shape Measurement Studies Based On Phase Measurement Methods

With the development of computer technique, electronics technique and modern optics information theory , the un-touched optics has an ocean of evolution.High-speed,high-resolution,un-touched,adjustability and low cost characterize the un-touched Optical 3D shape measurement technique.It has been widely used in Reverse Elngineering,CAD,Numerica1 Control Machining,fast Moulding,product Quality Inspection and medieal science etc.Phase-approaching of projected grating is an important embranchment of un-touched optics, the 3-D shape measurements were achieved using the deformed fringes by the height of the objects. The contour lines and Moiréseries were avoided, the data of analysis were offered, appropriate for realization of images processing automatization, the more information was obtained by adding density of images, then the high precision and delicacy were realized.In this paper,two measurement systems were desighned:one is the combination of digital shadow moirémethod and Fourier transform .the sinusoidal fringes were produced by computer, and projected by LCD projector, the reference image and deformed image were captured by CCD and saved in computer. The information of the object can be obtained through Fourier transform of the two images.The other is the combination of shadow moirémethod and phase-shifting transform.In the system some pulses produced by programming are sent to the IPC5373 which controls a step motor. Then the projection grating is moved tinily by using a mechanical device, which the phase-shift of 3-D shape measurement is achieved. The experimental results show that the system is simple and easy to be operated. The precision and the automatic measurement of the shape measurement are improved. Therefore, the system may have some practical value.We analyzed the error causing by projection,imaging, parameter of grating etc and improve the method to reduce the error.Another,we improve the method of objection image stripe and image dark to identify the image borderline and carry on its test.