Abstract:
Surface colour considered as a quality parameter change with the maturity of fruits. Many unripe
fruits initially show greenish surface colour which gradually changes to yellow colour when they
mature. The change of colour patterns is similar within each fruit category. The consumer often
judges the ripeness of the fruits by its colour. If the relationship between the surface colour of a
fruit category and the maturity can be determined, development of electronic devices capable of
sorting fruits automatically depending on the level of ripeness is a possibility. This is also useful
for grading fruits when they are being harvested. In this work, by applying image processing
techniques colour change with the maturity of Papaya fruits was studied. The commonly
available papaya variety ‘Red Lady’ was selected to carry out this work because they show
clear colour variation during the ripening period. RGB and OHTA colour spaces based image
segmentation algorithms were developed to detect yellow colour regions in papaya fruits. A
normalization technique was applied to reduce systematic bias due to the surrounding light
condition in the RGB space. Results show a non-linear increase in the surface yellow colour
with the age of the fruits. Preliminary results show that normalizing technique can help to reduce
this systematic bias.
