On a quest to find the tastiest watermelon for your Fourth of July cookout? There’s an Israeli app for that.

After experiencing the bitter frustration of trying to choose a good watermelon – only to get it home and find it hollow and tasteless – three computer science students at the Technion-Israel Institute of Technology decided to use technology to solve that age-old challenge. The result? A prototype that uses a smartphone, sensors and an algorithm to determine the quality of a watermelon in a matter of seconds – without ever opening the watermelon.

Through meetings with agricultural engineers and biologists around the world, Technion students Salah Abed Alehlim, Adam Garah and Ayman Sarha’an concluded there’s a correlation between a watermelon’s external and internal properties. It turns out that tone, color, stripe patterns, shape, and the size of the circle at the bottom of the watermelon all help determine what’s inside.

The app takes a picture of the watermelon from three angles, and uses an algorithm to analyze its external properties. The app then gives each watermelon a taste rating between 1 (“atrocious”) and 5 (“divine”).

Does it work? According to the students, the app (which is not yet available to the public) scored 100 percent accuracy in experiments on 30 watermelons. They also say it can be applied to examine the quality of other types of fruit.