由相移方法的手段阴影云纹地形_图文

1、 SHADOW MOIRE TOPOGRAPHY (d Fig. 10 Four moire images with shifted phases: (a shift =O, (b =1T/2, (C =rr, and (d =31T/2 in the case of 1= 200 mm, d 125 mm, and p=O.4 mm. method because the surface unevenness of 0.25 mm is too small to be contoured by this experimental arrangement. As is shown in Fig

2、. 10, contour lines are difficult to observe in four pictures with shifted phase. However, computer processing of the four images in Fig. 10 can produce a graphic representation of the result shown in Fig. 11, where the wireframe model is composed of 128 X 128 pixels. In practice, measurement is per

3、formed for about 256 X 256 pixels, and resolution in the x-y plane is 0.105 mm. For the calibration of measurement, cross-sectional profiles obtained by this method are shown in Fig. 12, with the result obtained by a mechanical contact profilometer. The two results agree well under the condition tha

4、t these measurements have to be performed differently. The ultimate resolution and accuracy attainable depend on uncertainty caused by the geometric arrangement of the to 5mm Fig. 11 Computed result from four images in Fig. 10. OPTICAL ENGINEERING / July 1993 / Vol. 32 No. 7/1673 Downloaded From: ht

5、tp:// on 02/26/2014 Terms of Use: /terms YOSHIZAWA and TOMISAWA (mm 0. - (mm 0.4 0.3 0.2 0.1 14 12 10 8 6 4 2 0.4 0.3 0.2 0.1 0 2 4 6 8 10 12 14 (mm 14 12 10 86 4 2 0 2 4 6 8 10 12 14 (mm ( By phase shift moire method (m (By phase shift moire

6、method 0.4 0.3 0.2 0.1 1412 10 8 6 4 2 0 2 4 6 8 10 12 14 (By contact profilometer (b ( By contact profilometer (a (mm Fig. 12 Comparison of measured results with respect to cross sections in Fig. 9: (a cross section AA obtained by phase-shift moire method and bya mechanical profilometerwith a conta

7、ct stylus and (bcross section BB obtained by same two methods. system. According to a calibration experiment in which a conical reference object (40 mm in diameter and 3 mm in height measured by a contact profilometer was compared with this optical result, standard deviation of the measured values i

8、n height was calculated as 0.021 mm in the case of a 0.73-mm interval of contours. This result means that height 3. J. Allen and D. Meadows, ' 'Removal of unwanted patterns from moire contour maps by grid translation techniques," AppI. Opt. 10(1, 210 212 (1971. 4. J. Bruning, D. Herriot

9、t, J. Gallagher, D. Rosenfeld, A. White, and D. Brangaccio, ' 'Digital wavefront measuring interferometer for testing optical surfaces and Ienses," Appl. Opt. 13(1 1, 26932703 (1974. is measured with accuracy of 1/35 of the contour interval; i.e., the fringe interval of moire can be vir

10、tually divided into 35 by means of phase shifting. 4 Toru Yoshizawa graduated and received his master's and doctor's degrees in precision engineering from the University of Tokyo. After doing research and educational work at Yamanashi University, he became a professor in the Department of Me

11、chanical Systems Engineering at Tokyo University of Agriculture and Technology. Conclusions Profilometry ofdiffused objects by shadow moire topography has been attempted with the aid of the phase-shift method. pose of 3-D metrology. Even with coarse moire fringes, highly precise measurement with acc

12、uracy of 1/35 of the fringe interval and automatic analysis of shape, including automatic identification of convex or concave surfaces, can be expected. On the basis of 256 X 256 pixel data, a complete 3-D profile of an object can be produced in a matter of a few Owing to the application of the phas

13、e-shift method to shadow moire, high-resolution measurement is attainable for the pur- His interests include practical optics, image metrology, and their applications to mechanical engineering. Teiyu Tomisawa graduated and received his master's degree in mechanical systems engineering from Tokyo

14、 University of Agriculture and Technology. His interests include optical metrology and image processing in the field of mechanical engineering. He is currently working on applimeasuring techniques to the car industry. minutes with a working system configured with a low-cost computer image-processing unit. References 1 . H. Takasaki, ' 'Moire topography,' ' Appi. Opt. 9(6, 14671472 (1970. cations of optical and mechanical 2. Moire Contourography and Its Applications, Japanese Society for Moire Con