Cotton inspection system benefits from digital upgrade

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Premier Evolvics, a leading Indian manufacturer of quality testing and online monitoring equipment for the textile industry, has upgraded its ART fibre testing machines with digital cameras from Allied Vision Technologies (AVT).

Assessing the quality of raw cotton fibres is a complex activity taking into account a large number of parameters such as the length, the strength, the elongation, the colour (reflectance, yellowness) or the number of contaminating materials (leaves, seeds, dirt) caught in the fibres.

The Premier ART (Automated Rapid Tester) from Premier Evolvics is an automated solution that operates at up to 150 samples per hour and eliminates the subjectivity of human perception.

Critical measurements such as fibre length and length uniformity, colour and trash rate are carried out using an optical solution. Cotton samples are placed in a special box with a transparent bottom and inspected by a built-in camera combined with the appropriate lighting. The images are processed by software modules evaluating the fibre length, colour quality and the percentage of dark particles (contamination). Other characteristics of the cotton are measured with non-optical methods (e.g. strength or micronaire, which describes both the maturity and fineness of the cotton fibre) using elongation and airflow.

The system was upgraded from an analogue to a digital imaging technology. The full digital data transmission increased the reliability of the system while cutting the frame grabber and the open source software helped save license costs. Instead of an analogue connectivity, the AVT Guppy interlaced camera is equipped with a FireWire IEEE 1394a digital interface enabling up to 25fps at full resolution.

'Because of the similar interlaced sensor technology, Premier Evolvics could take the benefits of a migration to a digital interface without having the drawbacks,' explains Anand Chinnaswamy, managing director of Lucid Imaging, AVT's distributor in India. 'No significant changes had to be done to the system architecture such as lighting or software algorithms since the image data delivered by the AVT Guppy have the same specifications as those delivered by the analogue camera.'