Samara University has developed a compact smartphone hyperspectrometer

Samara University scholars have developed a hyperspectrometer, which can be attached to any video- or photo-camera as well as to smartphones and tablets. This light extender of 25 mm in diameter can be widely used for the evaluation of water, soil, food, etc.

According to World Health Organization the reason of more than 200 diseases is unhealthy food, containing malignant bacteria and harmful chemical substances. One more risk factor is water resources that can be poisoned by chemicals because of soil contamination as well. The development of Samara University - supercompact hyperspectrometer - will help to orientate in the environment. With the help of this device any smartphone or any other gadget owner will be able to determine the extent to which this or that product is clean.

The making of compact, light and safe image-forming spectrometers has been worked at for several years at the university. The developments are being held on the basis of Department of Engineering Cybernetics and Institute of Image Systems Processing (IISP) RAS, the scientific advisor of which is Samara University President, academic of RAS Viktor Soyfer.

"Image-forming spectrometers divide a light beam not into three colour elements, as, for example, a camera, but into a set of 10, 30, and 100. Depending on their amount we call these devices differently", Roman Skidanov, Professor of Department of Engineering Cybernetics, Head of Research and Development Laboratory of computer-aided systems of research (RDL-35) tells. "If there are from 10 to 30 spectrum channels, this is a multispectrometer, and if, let's say, 100 and more, it is a hyperspectrometer".

The new development of the university scholars is a miniature version of a compact hyperspectrometer.  The scholars are engaged in creation of an extender construction with 25 mm in diameter and 30-40 mm in length. As Roman Skidanov has mentioned, such an attachment can be fastened on smartphones, tablets. It will allow these gadgets carrying out functions of image-forming hyperspectrometers, which can be used widely in everyday life, for instance, for evaluation of food and dishes as well as for water and soil. 

"If a supercompact hyperspectrometer is set on a smartphone, then everyone will have an opportunity to orient in the environment. This is very important, as, for instance, the access to safe food is the most important factor for life sustaining. And ecological environment, understanding if water or soil are contaminated is the token of health", Viktor Soyfer made the point. 

Theoretical basis for projecting of such optical system is presented in the article "Harmonical lens with circular aperture", issued in the journal "Computer Optics". The authors of the article - Roman Skidanov, postgraduate student of Samara University Yrii Strelkov and the chief programmer of Institute of Image Systems Processing RAS Sergey Volotovskiy - suggest using for making of the compact device the construction of planar image-forming lens on the basis of flat circular reflecting harmonical lens.

The developers have proved that the length of the lens built according to the suggested scheme can be several times less than its focal distance - from 0,05F to 0,1F. And computer modelling shows that the lens of 25 mm in diameter with the focal distance of 50 mm can have the height of several mm. 

Herewith, the cost of the main optical element of the hyperspectrometer - diffraction grating - according to Roman Skidanov, will not exceed several hundreds of roubles as Samara University has well tested original technologies for making diffractive optical elements (DOE).

In 2016 Chinese scholars patented a similar smartphone extender. Still, according to Roman Skidanov, it has an optical scheme, which needs a complex and high-precision setting that limits the capabilities of the device significantly and makes it more expensive and complex for production as well.

A simpler hyperspectrometer attachment is already embodied "in metal" by the scholars of Samara University. Its mass does not exceed 300 grams. After the attachment to a photo- or video device it will allow receiving a hyper-spectrum for every pixel of an image. The device is meant for the solution of tasks in industry and agriculture, where there is no need in compactability: it can determine the soil dampness distantly, presence of fertilizers in it. Such a hyperspectrometer attachment can be mounted to the equipment set of UAV for solution of different tasks of Earth Remote Probing.

For reference

Samara National Research University is one of the world leaders in the development of compact optical systems on the basis of diffractive optical elements (DOE). In November 2017, at the biggest technological conference in Europe WebSummit 2017 Samara representatives introduced the first in the world super-light diffractive lens. In it one optical element, weighing only 5 gr changed the complex and heavy system of lens and mirrors similar to the one being used in telephoto lens with focal distance of 300 mm and weigh of 500 gr.

Photo: Anastasiya Korotkova (Photoclub "Illuminator")