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Computer vision system
for milled rice quality analysis
Standardization is a strategy
to improve efficiency and global
competitiveness of the grain
industry. Under the national
standards on grains, milled
rice is classified based on its
size, degree of milling, and
amount of broken and other
defective grains in the sample.
The current practice of
classifying grains is by visual
inspection and manual separation
of each grain according to its
quality category and the result
is calculated on a percentage
weight basis. This type of analysis
is subjective and depends on
the skill of the classifier and
the working conditions.
To provide an objective,
accurate, and quick method of
analyzing milled rice, a group of
researchers led by Dr. Manolito C.
Bulaong of the Philippine Center
for Postharvest Development and
Mechanization (PhilMech) developed
the low-cost computer vision system
(CVS). It is composed of image
acquisition and processing systems.
The flatbed scanner is found to be
technically feasible as a low-cost
image acquisition device. Using the
flatbed scanner reduced the price
of the computer vision system by
94%. The set up using the flatbed
scanner is also simpler because the
scanner has its own light source.
For the image-processing
component, PhilMech developed
the milled rice quality classification
software. This software called
“caliper” was developed to measure
the length of milled rice using the
flatbed scanner. The software is a
faster and more accurate alternative to
manual measurement of milled rice.
Using the “caliper” software
took only about two minutes to
measure the length of about 100
grains compared with about 30
minutes using the manual method.
The main menu of the windowsgraphical
user interface (GUI) of the
software shows the acquired image
of milled rice and individual grain
classification data. The software
uses computer models for the
following: weight prediction, grain
size measurement, and classification
of grains into sound and defective.
This method is faster than
manual analysis used by the National
Food Authority, which takes more
than 2 hours. The computer time
for image acquisition, processing,
and grain classification takes less
than a minute. CVS also gives a
lower average coefficient of variation
of 0.159, compared with 0.363
for manual analysis. The CVS
makes the analysis of milled rice
quality faster, more convenient,
and more accurate than the
conventional, manual method.
Graphical User Interface of the “Caliper” software for measuring
grain size, % head rice, % broken grains, and % brewers.
The PCARRD Monitor 11