Image Based Estimation of Fruit Phytopathogenic Lesions Area

摘要

A method was developed to measure the surface area of walnut fruit phytopathogenic lesions from images acquired with a basic calibration target. The fruit is modelled by a spheroid, established from the 2D view ellipse using an iterative process. The method was tested with images of colour circular marks placed on a wooden spheroid. It proved effective in the estimation of the spheroid semi-diameters (average relative errors of 0.8% and 1.0%), spheroid surface (1.77%) and volume (2.71%). The computation of the colour mark surface area was within the expected error, considering the image resolution (up to about 4%), for 22 out of 28 images tested.