António de Oliveira Mendes

Optical Estimation of a Set of Pilling Coefficients for Textile Fabrics

This paper presents the results obtained using an experimental system, based on optical triangulation, which enabled topographic reconstructions of textile fabric surfaces. Consequently, one could evaluate and quantify the pilling formation through the optical estimation of a set of pilling coefficients. The proposed method was found to be precise, robust and systematic, and may constitute an alternative and/or complementary approach to quantify the pilling formation.

Virtual subjective pilling evaluation: an alternative

This paper reports an alternative approach for the evaluation of fabric pilling. On this approach, orthogonal projections of the three-dimensional (3D) fabric images are used directly to virtually evaluate the pilling formation of the fabrics. The 3D images of the fabrics are obtained through the reconstruction of the topography of the real textile fabrics. For that, a dual-scanning optical system (triangulation system) was used, which was developed and implemented by our research team. This evaluation approach is performed by comparing the appearance of the orthogonal projections of the 3D fabric images with the same photographic standard sets used in the conventional subjective method. For the validation of the obtained results with this methodology, a comparison was carried out relative to a reference subjective evaluation. This reference evaluation corresponds to a subjective evaluation of the fabrics originally performed by a panel of experts. A comparison was also performed between the results obtained with this methodology and those obtained by an objective evaluation. This objective evaluation corresponds to the automatic attribution of the equivalent pilling grade to the fabrics, based on the calculation of the total volume of pilling formed in their surfaces. The final results obtained with the described methodology were showed to be globally in agreement with both the reference subjective and the objective evaluations. Subsequently, this method shows potential as an alternative approach for the virtual subjective evaluation of fabric pilling.This paper reports an alternative approach for the evaluation of fabric pilling. On this approach, orthogonal projections of the three-dimensional (3D) fabric images are used directly to virtually evaluate the pilling formation of the fabrics. The 3D images of the fabrics are obtained through the reconstruction of the topography of the real textile fabrics. For that, a dual-scanning optical system (triangulation system) was used, which was developed and implemented by our research team.This evaluation approach is performed by comparing the appearance of the orthogonal projections of the 3D fabric images with the same photographic standard sets used in the conventional subjective method.For the validation of the obtained results with this methodology, a comparison was carried out relative to a reference subjective evaluation. This reference evaluation corresponds to a subjective evaluation of the fabrics originally performed by a panel of experts. A comparison was also performed between the results obtaine...

Subjective and Objective Pilling Evaluations of Textile Fabrics: A Comparison

This paper addresses a comparison between three different approaches used to evaluate a set of different textile fabric samples in terms of pilling formation. Originally, the set was subjectively evaluated by a panel of experts, being that, our reference evaluation. Then, the same set of fabrics was analysed by a dual-scanning optical system which has been implemented by our team to reconstruct 3D images of the topography of the fabrics. With the obtained range data, an objective evaluation of the pilling formation was carried out based on the total pilling volume and the results showed to be in agreement with the original subjective evaluation. In this paper, our purpose is to establish a correspondence model in order to automatically attribute the equivalent pilling grade. Furthermore, the same set of fabrics was then subjectively reevaluated by different observers for comparison with the reference evaluation, and the results obtained by the correspondence model.

Dual-scanning System for Optical Estimation of Pilling Formation

In this paper we present and fully describe an experimental system, based on optical triangulation, for fabric quality control purposes in the textile industry, namely for the objective quantification of pilling formation. The chosen settings, together with the criteria used for each parameter of the system, are boarded and were fixed in order to optimize the performance of the implemented dual-scanning system. Four different experiments were carried out to test and characterize the implemented system. Regarding the application of this system, the experimental results obtained for the optical estimation of the pilling formation, on a set of five different fabrics, have been shown to be in agreement with the subjective grade classification, meaning that the implemented dual-scanning system can be used to objectively quantify this parameter.

Three-dimensional surface reconstruction for evaluation of the abrasion effects on textile fabrics

Abrasion is responsible for many surface changes that occur on garments. For this reason, the evaluation of its effects becomes very important for the textile industry. In particular, pilling formation is a phenomenon that results of the abrasion process and affects fabrics more significantly altering their surface severely. The present work presents a method based on optical triangulation that enables topographic reconstructions of textile fabric samples and consequently, makes possible the evaluation and the quantification of the pilling formation that results from their topographic changes. Specific algorithms, written in the MatLab programming language, were developed and implemented to control the image data acquisition, storage and processing procedures. Finally, with the available processed data was possible to reconstruct the surface of fabric samples in three-dimensions and also, a coefficient to express the pilling formation occurred on the analyzed fabrics was achieved. Several tests and experiences have been carried out and the obtained results shown that this method is robust and precise.

Development of an Innovative 3D Simulator for Structured Polymeric Fibrous Materials and Liquid Droplets

An innovative 3D approach is used to develop and optimize structured polymeric fibrous materials. Using our own materials simulator we are able to design a new material with optimized properties such as porosity or thickness. In this work, for the first time we developed and tested a methodology to design a new fibrous material for which the penetration of a liquid drop can be predicted and optimized. The deposition of a liquid drop into a porous solid material is an important step in many materials applications like printing or filtration. The ability to control and predict the liquid kinetic deposition and the spreading area, are also determinant steps when developing new advanced materials, like structured porous materials, and new applications, like the transport of therapeutic molecules for medicinal purposes. We have used a methodology that includes an innovative 3D model for fibrous materials, an experimental plan to obtain 3D structures with different fibers, and an optic 3D prototype for collecting 3D data of the liquid drop deposition along time. We were able to quantify the time of deposition and the spreading area over time. Using the simulation model for fibrous materials we were able to simulate and produce in the laboratory an optimized structure for the ideal spreading area of the liquid droplet.

Development of an optical system for analysis of the ink---paper interaction

In this work is presented and described an optical system specifically designed and implemented to be applied for the study of the ink–paper interaction at the paper surface, considering the two main directions of the paper sheet (machine and cross directions). This work is particularly concerned with the system description, complete characterization, test, and its usage under real conditions. Concerning the system characterization, the main parameters were addressed and set having in mind its optimization. Relatively to the test of the system, several measurements using specific object samples with known dimensions were carried out to evaluate the accuracy of the obtained results. In terms of its usage under real conditions, an experiment was carried out using a commercial ink and common copy paper to dynamically collect data of its interaction. The collected data, after processing, enabled the determination of the main results of the analyzed ink–paper interaction, which allowed to reach the following conclusions; (1) the implemented system offers two different analysis approaches (qualitative and quantitative), both showing to be in agreement; and (2) the system also shows to be important to identify variations of the ink–paper interaction, manifested in the machine and cross directions of the paper.

Study of repeatability of an optical laser system for characterization of the paper fiber distribution and mass density

This work addresses the study of repeatability of an optical laser system, previously implemented by our research team, for characterization of the fiber distribution and mass density of two paper samples with different characteristics. In the experiment that has been carried out in the current work, both paper samples were laser scanned by the system on a total of 16 times (4 times per day in 4 different days). The data acquired and registered during the experimental work, associated to both tested samples, were then processed and the obtained results showed that the optical system is precise.

Retro-diffusion and transmission of laser radiation to characterize the paper fiber distribution and mass density

This work concerns the characterization of the fiber distribution and mass density of paper samples (extracted from paper sheets) using an optical laser system previously designed and implemented by our research team. To accomplish this task, the developed optical system was used to illuminate the paper samples with laser radiation, by opposite sides, while two image detectors captured images of the retro-diffused and transmitted laser radiation on each side of the paper samples. The captured images were then submitted to several processing routines to enable the assessment of the fiber distribution and mass density. In our experiments, two paper samples extracted from paper sheets of different characteristics were used. In terms of experimental work, the samples were both scanned with the system considering several points dispersed across their entire area, allowing the assessment of both parameters locally (for specific locations of the samples) and globally (considering the samples as a whole).

Study of the ink-paper interaction by image analysis: surface and bulk inspection

In this work, two optical systems previously designed and implemented by our research team, were used to enable the surface and bulk inspection of the ink-paper interaction by image analysis. Basically, the first system works by ejecting micro-liter ink drops onto the papers surface while monitoring the event under three different views over time. The second system is used for sectioning the paper samples through their thickness and to simultaneously acquire images of the ink penetration of each section cut. In the performed experiments, three black inks of different brands and a common copy paper were chosen, used, and tested with the two developed optical systems. Both qualitative and quantitative analyses were carried out at the surface level and in the bulk of the paper. In terms of conclusions, it was shown that the three tested ink-paper combinations revealed very distinct characteristics.