Edge Detecting Method for Microscopic Image of Cotton Fiber Cross-Section Using RCF Deep Neural Network

Currently, analyzing the microscopic image of cotton fiber cross-section is the most accurate and effective way to measure its grade of maturity and then evaluate the quality of cotton samples. However, existing methods cannot extract the edge of the cross-section intact, which will affect the measurement accuracy of maturity grade. In this paper, a new edge detection algorithm that is based on the RCF convolutional neural network (CNN) is proposed. For the microscopic image dataset of the cotton fiber cross-section constructed in this paper, the original RCF was firstly used to extract the edge of the cotton fiber cross-section in the image. After analyzing the output images of RCF in each convolution stage, the following two conclusions are drawn: (1) the shallow layers contain a lot of important edge information of the cotton fiber cross-section; (2) because the size of the cotton fiber cross-section in the image is relatively small and the receptive field of the convolutional layer gradually increases with the deepening of the number of layers, the edge information detected by the deeper layers becomes increasingly coarse. In view of the above two points, the following improvements are proposed in this paper: (1) modify the network supervision model and loss calculation structure; (2) the dilated convolution in the deeper layers is removed; therefore, the receptive field in the deeper layers is reduced to adapt to the detection of small objects. The experimental results show that the proposed method can effectively improve the accuracy of edge extraction of cotton fiber cross-section.

Sound absorption of weft knitted fabrics: influence of fibers cross-section shape, stitch density and mechanical modification of surface

PurposeOne of the recent applications of fabrics is to use them for sound insulation. Accordingly, due to their low production cost and low relative density, fabrics have drawn attention in some of the industries such as the automotive and aircraft industries. The present study is aimed to investigate the effects of the fiber cross-section, porosity, thickness of samples and fuzzing of the knitted fabric on the sound absorption coefficient.Design/methodology/approachIn the present study, fabrics with three different stitch densities were knitted by yarns consist of three different forms of fiber cross-section shapes (circular, elliptical and plus-shaped). In this work, the sound absorption coefficient of knitted fabrics was investigated with regard to the different fiber cross-sections and structural parameters using an impedance tube.FindingsAs indicated by the obtained results, the cross-section, porosity, thickness and mass per unit area of the fabrics were the determinant factors for the sound absorption coefficient. In addition to, the sound absorption coefficient and porosity were shown to have an inverse relationship.Originality/valueA section of the present paper has been allocated to the investigation of the effect of the fiber cross-section and fuzzing of fabric on the sound absorption of plain knitted fabrics.

Band Structure in a Sustainable Sonic Crystal

During the last few decades many researchers have been interested in acoustic wave propagation in artificial periodic composites known as sonic crystals. Sonic crystals have received renewed attention because they exhibit acoustic band gaps where there are only evanescent waves. Sonic crystals consist of a periodic array of scatterers embedded in a host medium. The host medium and/or scatterers are fluids. We investigate the band structure of acoustic waves propagating in a sustainable sonic crystal composed by miriti fibers and air, regarding square and triangular lattices. Miriti fibers are extracted from buriti palm petiole (Mauritia flexuosa Mart.), which is a typical specie that grows in Amazonian region. We also study the influence of miriti fiber cross section, i.e. circular, hollow circular, square and rotated square with a 45° angle of rotation with respect to x, y axes. Plane wave expansion method is used to solve the wave equation. Acoustic band gaps are observed for all miriti fiber cross sections and lattices. The best performances of the sustainable sonic crystal are for triangular lattice, regarding circular and rotated square miriti fiber cross sections, and for square lattice with circular miriti fiber cross section. We suggest that the sustainable sonic crystal should be feasible for noise management.