Three-dimensional measuring technique for surface topography using a light-sectioning microscope

Abstract

Three-dimensional (3D) surface topographic analysis, measurement, and assessment techniques have raised great interest not only among researchers but also among industrial users. Many industrial processes and applications are directly influenced by the small-scale roughness of surface finishes. This paper describes the development and implementation of a noncontact, three-dimensional, microtopography measuring system. The instrument is formed by combining a modified light-sectioning microscope subsystem with a computer subsystem. In particular, optical system characteristics of the light-sectioning microscope are investigated, and a textured steel sheet is measured to demonstrate good practical outcomes. Details of measuring processes and image processing algorithms are provided, such as procedures for measurement, image edge extraction, and 3D topography reconstruction. After the 3D topography of the measured surface has been reconstructed, the topography field description parameters are calculated. A standard roughness block was used for calibration of the surface microtopography measuring system. Results obtained showed the measurement method output has good agreement with the actual asperity (unevenness or roughness) of the surface. The computer subsystem is used to process and control asperity measurements and image generation, and for image acquisition and presentation.

Light-Sheet Microscopy for Surface Topography Measurements and Quantitative Analysis

“…al. [2]. Thus, choosing a system setup such that the illumination unit and the imaging unit are perpendicular to each other and at 45 degrees from the reference plane greatly simplifies the calculations.…”

“…Thus, choosing a system setup such that the illumination unit and the imaging unit are perpendicular to each other and at 45 degrees from the reference plane greatly simplifies the calculations. It should be mentioned that the system in Reference [2] uses a slit to generate the light-sheet, which causes significant energy loss. In contrast, we produce the light-sheet by compressing collimated light spot through a cylindrical lens so that the utilization of laser source is more efficient.…”

“…In contrast, we produce the light-sheet by compressing collimated light spot through a cylindrical lens so that the utilization of laser source is more efficient. We also create an infinite imaging space by using a tube lens, removing the need for an eyepiece, which is required in the system in Reference [2]. The geometrical model we utilize is also convenient and legible, as opposed to the complex light tracing based on the ABCD law utilized in Reference [2].…”

“…In traditional microscopic imaging, attention is on the 2D morphological characteristics of objects, however, it is impossible to acquire the full spatial information of an object with 2D image information. As a consequence, 3D measurements have become a commonplace inspection method for, e.g., textured steel sheets, silicon wafers and metallic surfaces [1][2][3].…”

Surface topography and mechanical properties of flax fibres modified glass ionomer restorative materials

“…Surface roughness can be measured qualitatively by scanning electron microscopy [17,18] or quantitatively by profilemetry [19] and light sectioning microscopy [20] . Recently, the atomic force microscopy (AFM) showed high capability to reveal more detailed information of surface topography [21] of resin composites after various treatments e.g., mechanical tooth brushing [22] , different polishing protocols [23] or in-office bleaching [24] .…”