Development and preliminary validation of an automatic digital analysis system for animal fibre analysis

Abstract

New equipment was designed and developed to evaluate the physical characteristics of animal fibres, based on an automatic digital analysis system (ADAS) that allows the capture of a series of real-time images. In the development of the mechanical component, a design tool was used that allows visualization, simulation, and documentation of the product. At the same time, an Atmel (ATmega328) microcontroller was programmed to enable displacement of table coordinates, focus of images, and reading of the temperature and humidity of fibre samples and the environment. The fibre images were processed using artificial vision technology. Algorithms were also developed for edge detection to define the diameter of the fibre in pixels. Finally, calibration was carried out using a regression and standardized samples of wool tops. The authors then weighted the pixels to µm with a standard sample. A friendly graphical interface was developed for management of the built equipment, visualization of results, calibration, data and graphic export, configuration, among others. For validation, average fibre diameter (AFD), standard deviation (SD), coefficient of variation and comfort factor (CF) were compared with values of top wool patterns. Finally, the measurements of OFDA 2000 and FIBER-EC were compared using student t-test and Pearson correlation. The results of the validation showed that the confidence limit of FIBER-EC, which varied between 0.075 and 3.47 µm, is similar to that of the confidence limit of Sirolan Laserscan and OFDA 2000. Accuracy is better than the OFDA 2000 for fibre assessments less than 25 µm, which vary between 0.034 and 0.250 µm.

Interlaboratory Test Performance of a Portable Fiber Tester

“…The precision of the PFT-assessed through standard deviation -, varies between 0.01 a 0.11 µm. These are low values compared with the POFITEST evaluation [5], and they indicated a good precision for the PFT. That is, when measuring AFD in a same sample with the PFT the AFD is repeatable.…”

“…The glass sheets were held together by adhesive tape on one end. The wool snippets were spread over a surface of one glass sheet using a spreader dispositive, at a controlled density, then covered with the second glass sheet, according to the operation procedure of PFT [5]. The prepared FHS with snippets was placed on the holder of the PFT and it was measured using the installed computer software.…”

“…Thus, finer wools can produce fabrics of characteristically light weight, soft, with superior handle and drape [4]. Therefore, it is important to measure fiber diameter of wool samples with a high accuracy, precision and quickness [5]. Currently, there are a few instruments in use to measure fiber diameter of either greasy or clean wool samples at wool center laboratory and warehouse [6]; however, those were lack of portability, price affordability, measurable limitation, and inflexibility for field use on farms.…”

Development of Calibration Models to Predict Mean Fibre Diameter in Llama (Lama glama) Fleeces with Near Infrared Spectroscopy

“…In order to obtain reference data to be used in NIR spectroscopy calibration, snippets from each sample were cut and then analysed using the Optical Fibre Diameter Analyser 2000 (OFDA 2000) [14]. This instrument determines the fibre diameter distribution by measuring individual fibres of snippets through an image digitalisation programme [33]. The parameters analysed were: mean fibre diameter (MFD) and standard deviation of MFD (SDMFD), both values expressed in micrometres; coefficient of variation of MFD (CVMFD), which is the percentage of the relationship between SDMFD and MFD; comfort factor (CF), which is the number of fibres less than and equal to 30 µm, divided by the total number of fibres, expressed as a percentage [34,35].…”

Calibration and validation of the mini-fiber EC image analysis instrument mean fiber diameter through direct or primary measurements

“…New device also include FibreLux (developed by FibreLux, Inc., Johannesburg, South Africa) and the portable fibre tester, 7 commercially designated as MiniFiber EC (MFEC), and uses digital image analysis. 8 These instruments quantify the quality traits of fibres objectively 6 within seconds, providing measurements of average fibre diameter, variation in fibre diameter and a prediction of comfort factor in some cases. These instruments do not directly measure in microns, that is, they require calibration and validation, 9 and/or comparison against another instruments.…”