Rapid crystal sizing on the pan stage by digital image analysis

Improving the control of crystal size on the pan stage has several potential benefits. These include increased productivity of high-grade pans. improved purging of highgrade fugals and better compliance with product sugar specifications for crystal size. Current practice relies heavily on the operator's experience to judge the size of crystals in proof samples viewed under a pan stage microscope. This paper reports on the development of an automatic crystal sizing system for pan stage proof samples using digital image analysis. The key steps, preparing the proof sample. providing correct illumination and developing the required sequence of image processing operations. are discussed. Two crystal size correlations are presented and results from factory testing of the clystal sizing system are reported.