New smartphone app can 'see' inside objects

You will soon be able to use your smartphone to scan fruits for pesticides, thanks to a new app developed by researchers that looks directly inside objects and displays its specific constituents.
Using the 'HawkSpex mobile' app, users can take out their smartphone, aim it at the object being scanned and get the desired information, for instance, whether an apple contains pesticide residues.
Although systems that perform such scans already exist, users usually have to clamp additional parts such as a prism onto the front of the integrated camera, researchers said.
This is costly and impractical and additionally interferes with a smartphone's design, they said.

"What makes our app special is that users don't need anything for a scan other than the camera already integrated in their smartphones," said Professor Udo Seiffert from Fraunhofer Institute for Factory Operation and Automation in Germany.
The app adjusts to different coloured light each time and ascertains how much of a colour's light is reflected by an object, thus generating a complete spectral fingerprint of the object.

The engineers use a mathematical model to extract just about any information on an object, like its constituents, from its spectral fingerprint.
"Since hyperspectral cameras are not integrated in smartphones, we simply reversed this principle," said Seiffert.

"The camera gives us a broadband three-channel sensor, that is, one that scans every wavelength and illuminates an object with different coloured light," he said.
Instead of the camera measuring luminous intensity in different colours, the display successively illuminates the object with a series of different colours for fractions of a second.
If the display casts only red light on the object, the object can only reflect red light - and the camera can only measure red light.
Intelligent analysis algorithms enable the app to compensate a smartphone's limited computing performance as well as the limited performance of the camera and display.

Seiffert hopes the app may be launched by the end of the year.