Fibre classification using on-line near infra-red spectroscopy

A fibre level is used in calculating the CCS of cane, the actual value being dependent on the class to which the cane belongs. The use of variety for classification of fibre levels in cane is the normal practice in the Australian sugar industry. It relies on the fact that there are high fibre and low fibre varieties. However, it treats all rakes of a variety the same, regardless of the amount of extraneous matter. This paper describes the successful use of on-line near infra-red (NIR) reflectance spectroscopy of prepared cane as a means of classification into high, medium and low fibre classes. The results showed a consistent difference between each class of about one unit, which is about 80% of the maximum achievable. This compares to 50% with class by variety. Some teething problems were experienced. However, the system showed itself to be very robust, continuing to classify in spite of changes to the calibration equation, lamp and main NIR detector. The use of NIR for fibre classification was readily accepted into the cane payment system by the growers, as it could clearly be seen to be an improvement over the existing system using variety.