Dimensional control of sand particles based on the Iranian National Standard Organization using image processing technique

Fourier series is a general technique for particle shape analysis. Lower order Fourier descriptors provide measures of roundness, elongation, asymmetry, triangularity and squareness. Higher order descriptors provide textural information like surface roughness. In this paper, firstly the captured image of sands grains is pre-processed to improving the quality of image in terms of edge sharpness, color and other image factors. Then, the sand shape characteristics is extracted using the Fourier series from the output Image of the previous step. In this work, two applications of the Fourier series in particle shape analysis are considered. First, the measurement of sand shape characteristics like elongation and triangularity which is important factors in cement mixture, plaster, other building applications and road construction. Secondly, the sizes of sand grains are also measured and compared to standardized classes used for each above mentioned applications to show the deviation from the standard specifies. The comparison between measured data from machine vision technique and conventional standard method show the efficiency of this new visual inspection system. The shape characteristics are not considered in conventional standard and only the dimensional measurement is developed. Therefore, using the machine vision method along with the Fourier series improves the current standard in terms of fast measuring speed, low cost measurement and adding the shape characteristics as well as the size of sands.