This paper addresses the development of an image analysis technique using the Fourier transform of the image to evaluate orientation in a fibrous assembly. The algorithms are evaluated using simulated images presented in Part I of the series. The results are compared with those for the tracking method presented in Part II.

In nonwovens, fiber orientation is an important characteristic because it directly influences the properties of the material. In a series of papers, we plan to explore the viability of image analysis algorithms for characterizing fiber orientation. In the first part of this series, we present a simulation scheme to produce images to test these different algorithms. As part of the series, we will present a direct tracking method in Part II, as well as Fourier and flow field analyses in subsequent parts for characterizing fiber orientation.

This paper extends the work of the first four parts of this series to apply the image analysis methods we have developed to characterize the fiber orientation of real non woven fabrics. The "real" fabrics chosen as typical are a carded crimped fiber web, two relatively dense overall or area bonded fabrics, a pattern or point bonded spun bonded-meltblown-spunbonded fabric, and a lightweight spunbonded nonwoven. In order to deal with real webs, it is necessary to develop a lighting system to give images with sufficient contrast along with an appropriate thresholding method to yield data suitable for analysis. The results indicate that the chord tracking method can charac terize orientation reliably when a direct measure is needed, and the information can be used to characterize and compare nonwoven laydown processes.

, This paper addresses the development of an image analysis technique for direct tracking of fibers in an assembly. The algorithms are evaluated using simulated images presented in an earlier part of the series. The tracking method appears to be extremely efficient in determining fiber orientation distribution in nonwovens regardless of their structural characteristics.

A multilayer model is proposed which predicts the equilibrium sorption isotherms for pure gases in Part I and for binary gas mixtures in Part II. This first part deals with the sorption of a pure gas or vapor, particularly by polymers. The model and equations are significantly different from those presently most used. The model gives good fits to the data against which it has been tested, particularly when used with sigmoidal isotherms. It allows the thermodynamic parameters to be calculated and gives important knowledge about the distribution and location of sorbed species.

This paper addresses the development of the image analysis technique of flow field analysis to evaluate local orientation in a fibrous assembly. The algorithms are evaluated using simulated images presented in Part I of the series. The results are compared with those from the tracking and Fourier methods presented in Parts II and III.

This paper reports the application of image analysis methods we developed previ ously to characterize fiber diameter distribution in nonwovens using a "distance trans form." The method is verified by a series of simulated nonwoven images as well as some real web images used previously, including a carded web, a relatively dense spunbonded fabric, and another relatively open area-bonded spunbonded. The results indicate that the distance transform can be used successfully to characterize fiber diameter.

No abstract