Texture may be defined with respect to the global properties of an image or to the repeating units that compose it. We have attempted to isolate the periodic components of texture in wool carpets for the purpose of assessing the effects of wear on carpet textures. Texture is defined as any recurring spatial pattern of sampled gray level intensities. We restrict attention to textural features that reflect the physical characteristics of the carpet tuft assemblies. Our test materials consist of four kinds of double ply wool carpets of differing textures divided into control, light, and heavy wear samples. Video images were recorded under several magnifications using a Truevision Vista board. Image files with 256 gray levels were converted to 32 levels using histogram equalization. Textural features were evaluated by computing gray level differences and second-order gray level statistics. We discuss results for spatial gray level dependence (SGLDM) and gray level difference (GLDM) methods for a range of intersampling distances. Results for our carpet series show that SGLDM and GLDM yield very similar trends, statistical trends within each method are correlated, overall, these measures are generally effective for differentiating the degree of wear as well as providing an indication of textural periodicity, and changes in frequency may be examined by subjecting SGLDM and GLDM statistics to spectral analysis. This study addresses the problem of characterizing vari4tions in carpet texture due to use degradation. We confine our discussion to the wear component of carpet degradation and ignore soiling, staining, photodegradation, and so on. Carpets typically have cut or looped structures, with yams arranged in raised loops or cut raised loops (tufts). Quantifying wear in carpets amounts to monitoring changes in these surface structures. Carpet tufts are subject to mechanical deformation during wear, and the resulting altered or degraded surface displays distinctive visual cues. Subjective ranking has been traditionally applied to wear assessment, since the visual aspect of surface wear is so apparent and, as noted in reference 15, aesthetic degradation may long precede extensive mechanical degradation. While this method of ranking may be quite replicable, the classification methods and their parameters are not as amenable to analytical treatment as one would like, because, as with many human judgment scales, the rules of perception and evaluation that define &dquo;appearance loss&dquo; characteristics are not well understood.Ultimately, it would be desirable to develop automated methods based on changes in the patterns of light reflectance and scattering, luminance, and color collectively referred to as texture. Texture is a very open-ended concept. There are many different kinds of image analysis procedures that are sensitive to changes in &dquo;texture.&dquo; However, it has been our experience that many of these techniques do not yield consistent results when applied to a wide range of texture patterns and are often di...

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In this study, the influence of stitch bonding on the tensile strength and tensile modulus in plain woven Twaron T-750/vinyl ester composites in the direction of thickness was examined. The effect of stitch density was investigated in longitudinal (warp) and transverse (weft) directions as a parameter. The space (opening) geometry and the deformation caused by the stitching process around stitch points were investigated. The stitching tension, stitch thread type and diameter were kept constant throughout the study. An increase in the tensile strength was observed for low stitching densities while there was no change in the tensile strength for medium stitching densities. A decrease in the tensile strength was observed for high stitching densities. It is especially noted that the tensile strength, which is on the transversal direction perpendicular to stitch direction, decreased with stitching density and tensile deformations initiated much earlier in this direction. It was understood that fiber deviations and resin rich areas were much more effective on these decreases compared with fiber deformation.