Vítor Carvalho

Yarn Diameter Measurements Using Coherent Optical Signal Processing

A method to measure variations in yarn diameter using coherent optical signal processing based on a single photodiode plus additional electronics is described. The approach enables us to quantify yarn irregularities associated with diameter variations which are linearly correlated with yarn mass variations. A robust method of system auto-calibration, eliminating the need for a temperature and humidity controlled environment, is also demonstrated. Two yarns that span the diameter ranges commonly used in the textile industry were used to verify the system linearity and ascertain its resolution. The results obtained have been verified using image analysis. Moreover, a diameter characterization was performed under real-world conditions for three types of yarns and a correlation with capacitive measurements is also presented. The system with sensitivity of 0.034 V/mm2 is able to detect minute variations of yarn diameter and characterize irregularities starting at very low thresholds (commercial systems generally characterize variations of 30% or greater relative to the average value).

Optical Yarn Hairiness Measurement System

This paper presents a system developed for measuring yarn hairiness using a coherent optical signal processing technique, in steps of 1 mm. The system hardware is divided into two main parts: optical, for establishing an image regarding yarn hairiness and electronic, which converts the optical signal to a proportional voltage signal. Additionally, software using LabVIEWTM was also designed to acquire the output voltage with a data acquisition board (DAQ) and to perform the corresponding data processing. This system is able to quantify the traditional commercial hairniness parameters, as sH (%), CVH (%), H and spectral analysis based on FFT. In addition several other parameters, novel in textile characterization, such as DRH (%), IDRH (%), UH (%) and spectral analysis based on FWHT and FDFI are readily available. The results obtained using this system to characterize a 4.20 g/Km cotton yarn are presented.

Development of a Yarn Evenness Measurement and Hairiness Analysis System

This paper presents an automatic yarn characterization system, based on capacitive sensors for evenness measurement and on optical sensors for hairiness analysis. This approach enables direct yarn mass determination in 1 mm range for evenness, an increase by a factor of eight over the most common commercial solutions (8 mm), and will also enable hairiness measurement up to 1 mm with high accuracy. This system determines all parameters commonly used in textile industry, for different sensitivity values defined by the operator. It also presents new parameters, not measured by commercial equipments (integral deviation rate-IDR, different signal processing techniques to detect error patterns (fast Walsh-Hadamard transform-FWHT) and other adapted parameters (deviation rate-DR, spectrograms (fast Fourier transform-FFT), coefficient of variation-CV, mean deviation-U, number and length of faults)

Serious game as a tool to intellectual disabilities therapy: Total challenge

Nowadays there are games that involving a challenge and using a reward system are designed to solve problems in several areas. These games, called serious games, do not put aside the entertainment, although this is not their main purpose. Among the problems that can be solved or at least mitigated with the help of serious games, there are highlighted those involving health care and especially intellectual disabilities. Despite the existence of a variety of serious games intended to minimize health problems, there is still much work to be conducted within the problems related to intellectual deficiency. Thus, this study intends to investigate the evolution of patients with intellectual disabilities using a serious game capable of monitoring their evolution, concerning memory, decision-making time, capacity of observation, learning and applying knowledge.

Automatic Yarn Characterization System: Design of a Prototype

This paper presents Yarn System Quality (YSQ), an innovative, low-cost, portable and high-precision yarn evaluation tester, for quality control of yarn characteristics under laboratory conditions. It presents a modular architecture, simultaneously integrating measurements of yarn hairiness, mass, regularity and diameter. An external module to obtain the yarn production characteristics using analogue optics and image processing is also available. The quantification of yarn hairiness and diameter variation (with a sampling resolution length of 1 mm) is carried out using photodiodes; the diameter characterization, based on 0.5 mm width samples, employs a linear photodiode array; the measurements of mass variation, based on samples of 1 mm, uses a parallel plate capacitive sensor. In the YSQ measurement parameters based on optical sensors a coherent signal processing technique with Fourier analysis is used, to obtain linear output signal variations. A comparison between the results obtained using the YSQ tester and a commercial solution is also presented.

Yarn Evenness Parameters Evaluation: A New Approach

This paper presents MPS1 (Mass Parameterization System), an automatic system for determination of mass characteristics of textile yarn. It is based on 1 mm parallel capacitive sensors, working online or offline. This new approach allows direct measurement of yarn mass in the 1 mm range (increasing the resolution by eight times) [Pinto, J. G., Dissertação de Mestrado, Minho University, 2004; Baxter, L. Capacitive sensors: design and applications, IEEE Press, 1997]. Acquisition and data processing are performed in Labview™ from National Instruments. All parameters commonly used in the textile industry are determined for different values of sensitivity defined interactively by the operator. In MPS1, the new parameters were used (integral of deviation rate [IDR%], signal processing techniques based on the fast Walsh-Hadamard Transform and on fast impulse frequency determination [FDFI]) and others adapted (deviation rate [DR%], spectograms, frequency and mass variation diagrams, coefficient of variation [CV%], mean deviation [U%], faults counting and extension). Anew feature of this system is also the online automatic quality classification of mass parameters.

Automatic yarn characterization system

This paper presents an innovative, low cost, portable and high-precision yarn evaluation tester, YSQ (Yarn System Quality), for quality control of yarn characteristics under laboratory conditions. It presents a modular format, which can integrate simultaneously yarn hairiness, mass, regularity and diameter measurements. The quantification of yarn hairiness and diameter variation (with a sampling resolution length of 1 mm) is carried out using photodiodes; the diameter characterization, based on 0.5 mm width samples, employs a linear photodiode array; the measurements of mass variation, based on samples of 1 mm, employs a parallel plates capacitive sensor. In the YSQ measurement parameters based on optical sensors, a coherent signal processing technique with Fourier analysis is used, to obtain linear and consistent output signal variations. A comparison between results obtained using the YSQ and a commercially available solution is presented.

Application for physiotherapy and tracking of patients with neurological diseases - Preliminary studies

As a significant number of individuals has severe motor disabilities, due to neurological diseases, it is important to provide appropriate rehabilitation programs to improve their quality of life. Several studies suggest that serious games have a tremendous potential as rehabilitation tools. Thus, the objective of this work is to develop an application, to run as a serious game in the near future, to monitor the major physiotherapy movements of people with neurological diseases. This application will be based on Image Processing techniques, to verify whether the patient is correctly performing the physiotherapy exercises.

An Overview of Industrial Communication Networks

The authors of this paper are grateful to national funds by FCT—Fundacao para a Ciencia e Tecnologia in the scope of the project: PEst-OE/EEI/UI0319/2014.

Yarn-Mass Measurement With 1-mm-Length Samples

In textile production, measurement of yarn mass in the 1-mm range is of utmost importance to properly evaluate evenness, as several irregularities occur in 1-4-mm yarn length. Direct measurements in the 1-mm range are not available in commercial equipment. One of the most common, from Uster, is based on yarn samples of 8 mm. This paper presents a direct mass measurement in the 1-mm range system based on parallel capacitive sensors and signal-processing techniques for detection of periodical errors. Results point out that evaluation of yarn mass, with this approach, is feasible in the 1-mm range, allowing online measurement (1-mm yarn mass) in a spinning frame for real-time control. Despite low signal-to-noise ratio, it is possible to measure small variations of yarn mass (typical capacity variation of 2.08times10-17 F for 57 tex-0.057 g/m of yarn). As a spin-off of this project, a new low-cost control system is being prepared for detection of yarn break and bobbin end in knitting flat machines. Online quality classification is also feasible with the developed system