A Novel <i>In Situ</i> Roughness Measurement Based on Spatial Average Analysis of Binary Speckle Image

Abstract

This study proposes a novel optical technique and method for in-situ roughness measurement. The speckle image was obtained by illuminating a laser beam and the reflected laser pattern image from a surface was binarizd and examined. The intensity distribution of binary image utilizes the combined effects of speckle and scattering phenomena. A new parameter of intensity distribution of binary image, Sd BD has been proposed and the surface roughness parameter Ra of machined surfaces (ground) were correlated experimentally. Measurement results demonstrate an excellent correlation between the SdBD and Ra with correlation coefficient of 0.9706. The practicality of the proposed method to in-situ roughness measurement was applied to six samples from roughness Ra 0.2 to 6.25μm (0.3 λ and 10 λ, where λ is diode laser wavelength) of steel through grinding process.

Rapid in-process measurement of surface roughness using adaptive optics

“…Integrating the proposed measuring device with an AO system can achieve a measurement error of less than 8.7% as compared with the stylus method. Experimental results also show that the AO-assisted system in conjunction with the proposed method has much better performance than that reported previously [6] in terms of correlation coefficient (R 2 0.9967). Hence, the proposed AO-assisted system has the ability to reduce measurement error and laser aberrations under turbulence, and has great potential for in situ surface roughness measurement.…”

“…However, this approach has certain disadvantages, such as high contact pressure on the object surface, long measurement time, and difficulty measuring surface roughness in real time. Researchers have developed optical techniques to solve these problems, including the speckle method [4][5][6] and light scattering [7]. Typical measurement results obtained from optical approaches agree reasonably well with the stylus methods and routinely achieve less than 10% error values.…”

Direct-write, highly aligned chitosan-poly(ethylene oxide) nanofiber patterns for cell morphology and spreading control

“…Figure  6 shows the relation between cell spreading and different positioning densities using a binary image method as reported previously [36,37]. Cell viabilities and spreading after culture for 1 and 3 days with various positioning densities of CNF are illustrated.…”

“…Here the binary image analysis [36,37] of pixel counts for dark (D) and bright (B) regions are taken from the optical images of cells cultured for 1 and 3 days to account for cell spreading. In the binary processing, it should be noted that B region counts decrease and D region counts increase with the increase in cell spreading.…”

Adaptive Optics Integrated Surface Roughness Measurement of Sputtered PT Film on Silicon Substrate

“…. Optical techniques have great potential to overcome these problems, including the speckle method and light scattering , which are applicable to surface roughness measurement. Typical measurement results obtained from optical approaches agree reasonably well with the stylus methods, and routinely achieve less than 10% error values.…”