Capturing Nature without Contact

Laboratories and Equipment in Biosystems Engineering

Spectroscopy Laboratory

The Spectroscopy Laboratory contains a complete test stand for hyperspectral imaging in various wavelengths, including an artificial broadband light system. Currently available camera systems are capable of recording spatially resolved absorption spectra in a wavelength range of 1.0 to 2.5 µm. The sensor cooled to around 195 ° K has a spectral resolution of 6.25 nm in 256 equidistant spectral channels. It digitizes at 14 bits.

© Fraunhofer IFF
Dielectric spectroscopy setup. A laptop controls and displays recorded spectra online. The control electronics are completely integrated in an embedded PC and the sensor head.

In the TEPROSA project in cooperation with Otto von Guericke University Magdeburg, we developed a special spectroscopy system in the VHF range that employs a dielectric sensor and artificial intelligence to analyze data. It is used for the online identification of complex mixtures of substances in liquids.

The sensor head consists of highly durable, biocompatible ceramic. The system operates in a frequency range of 15 kHz to 150 kHz, regularly scanning 400 channels. A complex impedance spectrum that characterizes the biochemical composition of liquids can be recorded within one second. The measurement electronics are highly integrated and data is evaluated in an embedded PC.

© Fraunhofer IFF
A test setup combined with a conveyor that records multichannel acoustic spectra. The impact of the measured object, in this case walnuts undergoing quality testing, on an impact plate generates a characteristics acoustic spectrum that can be used to quantify relevant object properties and control the subsequent sorting plant.

The Spectroscopy Laboratory has various acoustic sensors that record spectra of acoustic signals. They consist of microphone arrays and seismic sensors. They record multichannel acoustic spectra in the frequency range of 20 Hz to 20 kHz. Using specially developed pattern recognition software, they can, among other things, quantify relevant properties of objects when they strike an impact plate.

Aerial Hyperspectral Images

© Fraunhofer IFF
Aerial hyperspectral imaging system. An adaptor specially designed and made for this application is used to mount all of the components on an aircraft’s exterior, thus allowing its use on any aircraft. A separate energy supply system and an imaging computer are on board the aircraft.

We have developed a system, mountable on common service aircraft (e.g. general aviation aircraft, agricultural aircraft), which uses hyperspectral camera systems to take aerial photographs. In addition to a hyperspectral camera, the system has a conventional color camera, GPS and integrated sensors that record an aircraft’s flight dynamics, acceleration and the like during measurements. This makes it possible to record correctly georeferenced and rectified hyperspectral images from any flight level. The system has its own energy supply system and is thus independent of the aircraft’s electrical system.