Image Analysis for Cotton Fibers Part II: Cross-Sectional Measurements

Abstract

Cross-sectional analysis of cotton fibers provides direct, accurate measurements of fiber fineness and maturity, which are often regarded as the reference data for validating or calibrating other indirect measurements of these important cotton properties. Despite the importance, cross-sectional methods of using image analysis have not been broadly applied to cotton quality evaluations because of the tedious procedures for both preparing cotton samples and processing cross-sectional images. This paper illustrates image processing procedures dedicated to cotton cross-sectional analysis for the purpose of increasing the efficiency and accuracy of fiber separation and feature extraction. These procedures greatly improve the automation of processing cotton cross-sectional images and increase the number of analyzable fibers per image. The cross-sectional data of cotton fibers also have good correlations with longitudinal data and data from the Advanced Fiber Information Systems.A cotton cross section contains measurable information directly related to the maturity of the fiber. Crosssectional measurements of cotton maturity may be used as a reference when other methods need to be calibrated.Much research has been conducted with image analysis technology to measure cotton maturity and other parameters from fiber cross sections [4][5][6][11][12][13][14][15]. The success of a cross-sectional method using image analysis largely relies on two techniques: fiber cross-sectioning and image segmentation. Cross-sectioning is the most import step in obtaining analyzable images of fibers, and grinding and cutting are the two general methods for fiber cross-sectioning. In grinding, a bundle of fibers embedded in a polymer resin and hardener mixture is hardened, ground, then polished, and the surface containing the fiber cross sections is imaged on a microscope by reHected light [9]. There are many different ways of cutting a thin slice of fibers perpendicular to the long axes [ 1, 3]. A quick embedding method specifically for cotton fibers was established by researchers at the USDA Southern Regional Research Center (SRRC) [3]. A bundle of fibers is embedded in a methacrylate medium, polymerized in a uv reactor, and cut into 1-3 tkm slices with a microtome. This sectioning method greatly improves the separability and contrast of individual fibers in the image captured by transmitted light. ' Image segmentation is a computational process that separates cotton cross sections from the image background and from one another. Segmentation results directly influence the efficiency and accuracy of crosssectional measurements. Due to variations in the crosssectional shape and thickness of the sliced samples. fibers in different regions may exhibit different levels of contrast and focus in an image. There are always cross sections that contact or overlap others in the image. Some appear to be damaged due to scratching of the cutting knife. Cotton cross sections can have convex or concave boundaries, and hollow or solid cores, making many p...

Transgenic cotton over-producing spinach sucrose phosphate synthase showed enhanced leaf sucrose synthesis and improved fiber quality under controlled environmental conditions

“…Theta: (a) is the ratio of the area of the cell wall to the area of a circle having the same perimeter as the fiber section, thereby indicating fiber maturity; and (b) is mathematically related to AFIS Maturity Ratio, which equals Theta/0.577 (Pierce and Lord 1939). Images of randomly chosen fiber cross-sections (400 or more per plant; ‡1,600-2,000 per line) were digitized (Hitachi HVC-20 3CCD camera with Coreco Oculus TCX frame grabber) and quantitatively analyzed by Fiber Image Analysis System software (Xu and Huang 2004).…”

Macro and Micro Characterization of Biopolymers: Case of Cotton Fibre

“…Therefore, Image Analysis presents a quick and reliable technique for determining the cotton fibre maturity which consists of performing cotton fibre cross-section, acquiring and analyzing their image to determine: Perimeter, Area and Theta (degree of secondary wall thickening of cotton fibres). (Xu & Huang, 2004) Figure 2 shows a schematic cross section of the cotton fibre; the shaded area is the secondary cell wall and the linear dimension measured along the outer periphery of the fibre is called the perimeter. …”

Analysis of the physical properties of developing cotton fibres

“…The primary cell wall determines the length of the cotton fibre, while the secondary cell wall determines fibre strength [44]. The summary of fibre length measurements of developing cotton fibres is presented in Figure 4, wherein it is observed that a significant increase in fibre length up to 24 dpa; this observation is in agreement with Schubert et al [45] who reported a rapid increase in fibre length to 27 dpa, and Benedict et al [46] who showed an increase in fibre length of cotton fibres until 25 dpa.…”