This study was conducted to develop a fast and accurate
computer-based machine vision system
for detecting irregular potatoes
in real-time.
Supported algorithms
were specifically developed and programmed
for image acquisition and processing, controlling the whole process, saving the classification
results and monitoring the progress of all operations. A database of images was first formulated from
potatoes with different shapes and sizes, and then some essential geometrical features such as perimeter,
centroid, area, moment of inertia, length and width were extracted from each image. Also, eight shape
parameters originated from size features and Fourier transform were calculated for each image in the
database. All extracted shape parameters were entered in a stepwise linear discriminant analysis to
extract the most important parameters that most characterized the regularity of potatoes. Based on stepwise
linear discriminant analysis, two shape features (roundness and extent) and four Fourier-shape
descriptors were found to be effective in sorting regular and irregular potatoes. The average correct classification
was 96.5% for a training set composed of 228 potatoes and then the algorithm was validated in
another testing set composed of 182 potatoes in a real-time operation. The experiments showed that the
success of in-line classification of moving potatoes was 96.2%. Concurrently, the well-shaped potatoes
were classified by size achieving a 100% accuracy indicating that the developed machine vision system
has a great potential in automatic detection and sorting of misshapen products.