Oranges and mandarins are inspected using artificial vision

Oct 11, 2011

Scientists at the Valencian Institute of Agrarian Research (IVIA, Spain) have created a machine that detects and separates rotten oranges, another that classifies mandarin segments according to their quality and another that helps citrus fruit pickers out in the field. All prototypes use computer vision to automatically inspect the fruits.

Until now, rotten oranges have been detected manually in dark rooms with the help of that illuminates the in damaged rind through fluorescence. The job is carried out in strictly timed shifts due to the risk that this type of light poses. However, a team of researchers from Valencia have just created a machine that can carry out the task automatically.

José Blasco, researcher at the IVIA and a member of the team that patented the machine explains that "through collaboration with a company within this sector, we have developed software and hardware that can locate rotten and discard of those that are not fit for sale."

This creation is just one of the many agricultural applications developed by these scientists in the last 20 years thanks to advances in artificial vision, a series of techniques that allow for a computer to be programmed so that it "understands" the image it has in front of it and can act accordingly. The results have been published in the Food and Bioprocess Technology journal.

Another of the machines -in the presence of visible light- classifies citrus fruits on the production line according to their quality, colouring and the type of damage that the skin presents. In this way, first class fruits that are destined for more demanding markets can be separated from second class fruits that are perfectly edible despite having some small defect like being bruised or scratched. The analysis is carried out at a speed of 15 to 20 pieces of fruit per second.

Researchers have also developed a device that automates the inspection of ready-to-eat segments. After being individually separated on a vibrating platform, they are transported on a conveyor belt to the inspection area which is able to examine 28 segments per second. At this stage, the broken segments are separated from the whole segments and the same goes for those with or without pips. Skin and any other foreign bodies are also identified and eliminated from the production line.

Blasco outlines that "as well as developing property statistical and computing techniques, the use the highest image resolution that modern equipment can achieve. They are capable of analysing objects in regions of the electromagnetic spectrum that the human eye cannot see such as ultraviolet and infrared."

Medical techniques for analysing fruit

"We have even started to inspect the internal quality of fruit using magnetic imaging resonance (MRI), computerized axial tomography (CAT) or X-rays, like those that are used in medicine," he adds. "Although at the moment, these are costly techniques and we must continue in our investigations so as to facilitate their installation and make them more efficient in the fruit selection process."

One of the latest investigations focuses on the use of hyperspectral imaging, which collects and processes information from a large part of the electromagnetic spectrum and provides individual spectral measurements for each pixel. This method can be applied as a way of identifying chemical compounds whose concentrations can change as the fruit ripens or rots. Therefore, it is possible to predict the perfect time to eat the fruit or, indeed, to track the evolution of a disease in the fruit.

The most sizeable of IVIA's projects is a machine that helps during the picking of citrus fruits and it is the size of a large tractor. Blasco highlights that it is a self-propelled prototype capable of classifying oranges whilst still out in the field. As a result, he states that "it is very important that the inspection system is highly efficient from an energy consumption point of view."

Operators pick the fruits and place them on the machine's mobile belt. Quality, colour and the presence of external damage is determined using sensors and a vision system.

The information gathered by the sensors is then transmitted to an automated logic controller in order for the fruit to be classified into the three established categories. Upon arrival at the warehouse, the has already been preclassified and comes with complete statistics on its quality. This allows for it to be valued and its immediate destination can be decided upon.

Explore further: Video: Researchers instruct scientists in giant role tiny fungi play

More information: Sergio Cubero, Nuria Aleixos, Enrique Moltó, Juan Gómez-Sanchis, Jose Blasco. "Advances in Machine Vision Applications for Automatic Inspection and Quality Evaluation of Fruits and Vegetables". Food and Bioprocess Technology 4(4): 487-504, 2011. DOI:10.1007/s11947-010-0411-8

Provided by FECYT - Spanish Foundation for Science and Technology

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Laser Shows if Fruit's Beauty is Only Skin Deep

May 08, 2005

The produce industry is working with the Agricultural Research Service (ARS) to make sure that fruits and vegetables taste as good as they look. They're counting on "machine vision" tools that can predict ...

Recommended for you

France fights back Asian hornet invader

2 hours ago

They slipped into southwest France 10 years ago in a pottery shipment from China and have since invaded more than half the country, which is fighting back with drones, poisoned rods and even chickens.

Tide turns for shark fin in China

2 hours ago

A sprawling market floor in Guangzhou was once a prime location for shark fin, one of China's most expensive delicacies. But now it lies deserted, thanks to a ban from official banquet tables and a celebrity-driven ...

New research reveals clock ticking for fruit flies

3 hours ago

The army of pesky Queensland fruit flies that annually inflict many millions of dollars-worth of damage on the nation's horticultural industry may be about to see their numbers take a significant dive thanks ...

The ABC's of animal speech: Not so random after all

5 hours ago

The calls of many animals, from whales to wolves, might contain more language-like structure than previously thought, according to study that raises new questions about the evolutionary origins of human language.

Manatees could lose their endangered species status

15 hours ago

About 2,500 manatees have perished in Florida over the last four years, heightening tension between conservationists and property owners as federal officials prepare to decide whether to down-list the creature to threatened ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

hush1
not rated yet Oct 11, 2011
Replace the words 'fruit','oranges', 'citrus', and 'mandarin' with the word 'humans' throughout the entire article.

Many a truth spoken in...
jest.