Laser Shows if Fruit's Beauty is Only Skin Deep

May 08, 2005
Laser Shows if Fruit's Beauty is Only Skin Deep

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 the quality of fruit or vegetable flavor--right after picking and in the packing plant--without ever touching the product. Machine vision uses optical sensors to inspect objects.

Image: Using a multispectral imaging system to collect light scattering from the fruit, visiting assistant professor Yankun Peng (from Michigan State University) estimates apple firmness.

Today, batches of fruits and vegetables are judged by sample tastings, but there is no guarantee that all of the produce in the batch will taste the same. Samples are also tested for firmness by mechanically stabbing them with a thick, steel probe. With both methods, the tested produce has to be thrown away.

While there are machine vision tools that can check skin-deep traits like size, color and bruising, it is difficult to judge deep, internal qualities like taste and texture of apples and many other fruits. Now Renfu Lu, an agricultural engineer with the ARS Sugar Beet and Bean Research Unit in East Lansing, Mich., has developed machine vision prototypes that "taste" every single piece of produce from right after harvest to when it passes by on the packing line.

Lu and ARS colleagues on the campus of Michigan State University have tested their laser prototype on apples and peaches. It should work with any produce that is at least as large as an apple or peach. The detector focuses four laser beams, each a different light wavelength, into one sharp beam that shines into individual fruits.

Laser light photons momentarily scatter all the way to the fruit's core and back. The amount of light bounced back after interacting with tissue reflects firmness. Peaches and apples are separated by whether they are soft, firm or hard.

Since scattered light also indicates the amount of light absorbed by the fruit, and that absorption is affected by sugar levels in the fruit, this technology can be used to predict flavors, such as sweetness in apples.

Source: Agricultural Research Service

Explore further: Study finds female entrepreneurs are discounted because of their gender

add to favorites email to friend print save as pdf

Related Stories

Giant virus revealed in 3-D using X-ray laser

Mar 03, 2015

For the first time, researchers have produced a 3-D image revealing part of the inner structure of an intact, infectious virus, using a unique X-ray laser at the Department of Energy's SLAC National Accelerator ...

Throwing light on a mysterious human 'superpower'

Mar 02, 2015

Most people, at some point in their lives, have dreamt of being able to fly like Superman or develop superhuman strength like the Hulk. But very few know that we human beings have a "superpower" of our own, ...

Image sensors that behave like biological retinas

Feb 18, 2015

Ever since the invention of the first camera obscura and the advent of photography in the 19th century, scientists have been fascinated by the use of light sensors to capture the world around us from the ...

Recommended for you

New (road) signs of the times?

25 minutes ago

Traffic accidents claim lives, cause injury and cost money. Working on ways to reduce them is a constant battle.

Is generosity essential to human existence?

2 hours ago

When Dennis ole Sonkoi was a child he never gave much thought to sharing. Growing up in Kenya as part of the Maasai community – a pastoral group of herdsmen that travels throughout Kenya and Tanzania – ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.