Measurement and study on drying shrinkage characteristic of tobacco lamina based on computer vision

Abstract

Accurate evaluation of shrinkage characteristic for tobacco lamina during drying process is important for optimizing tobacco primary process. The present work developed a detection and characterization method of shrinkage characteristic based on computer vision. Effect of types and dimensions of tobacco lamina on the shrinkage characteristic were investigated and shrinkage rate variation at different drying stages was also analyzed by this method. The results show that percentage reduction of area, which is obtained by detecting tobacco lamina area before and after drying, can be used to reflect the shrinkage characteristic of tobacco lamina. RSD of measurement results by this method is less than 6% under test conditions. Compared with upper tobacco leaf, middle tobacco leaf shows the higher shrinkage rate of 14.3%. Dimensions of tobacco lamina also have significant effect on its shrinkage characteristic. The larger size (up 30mm mesh) tobacco lamina shows a higher shrinkage rate. Shrinkage rate of tobacco lamina is closely related to moisture content variation during drying. The shrinkage of tobacco lamina during drying mainly occurs within the moisture content range of 20% to 14%.