Constructing a Three-Dimensional Image of Surface Texture from Profilograms

Abstract

New requirements on the microgeometry of machine parts’ working surfaces are considered. To calculate the microgeometric characteristics, information regarding the three-dimensional distribution of the microrelief height is required. In other words, textural parameters of the microgeometry are required, rather than profile parameters. In the present work, three-dimensional images of surface microrelief are obtained by simple and accessible methods of deriving information regarding the surface texture— specifically, by means of a profilograph. A profilogram of the precision surface obtained by methods outlined in the corresponding GOST State Standards is used to construct a three-dimensional model of images of the surface microrelief. Then digital values of the signal along the axis of the profilogram are introduced in the computer as a one-dimensional array. The number of elements in this array will determine the size of the image along the X axis (in pixels). This one-dimensional array is regarded as a random iteration of the video signal along the X axis, as if obtained using a video camera. Repetition along the Y axis permits the creation of a three-dimensional model of the surface. However, this image of the 3D surface model does not fully represent the surface microrelief, since each subsequent row of the image completely reproduces its predecessor derived from the initial profilogram. To address this problem, a random component is introduced using a pseudorandom-number generator, so as to add noise to each successive row of the image. The graphs of the video signal for different rows are significantly different. That reflects the texture of the actual microrelief. Thus, the proposed method of image construction yields a 3D model of the surface texture for subsequent optical–electronic analysis of the signals, without the need for complex and expensive equipment.