Spectroscopic 'science camera' system for smartphones the future for mobile health

September 18, 2017 //By Jean-Pierre Joosting
Researchers at the University of Illinois would like to sell mobile device manufactures on the idea of adding yet another image sensor (third camera) as a built-in capability for health diagnostic, environmental monitoring, and general-purpose color sensing applications.

The National Science Foundation provided a pair of University of Illinois professors with a grant to develop technology called "Lab-in-a-Smartphone three years ago." Over that time, the research teams of Brian Cunningham, Donald Biggar Willett Professor of Engineering, and John Dallesasse, associate professor of electrical and computer engineering, have published papers detailing potential ways the mobile devices could provide health diagnostic tests and other measurements normally performed in a laboratory setting. 

The researchers have demonstrated that mobile devices incorporating their sensor can provide accurate measurements of optical absorption spectra of colored liquids or the optically scattered spectra of solid objects. A mobile device incorporating the lab-in-a-smartphone "science camera" can accurately read liquid-based or paper-based medical tests in which the end result is a material that changes from one color to another in the presence of a specific analyte.

A very compact inexpensive system that performs optical spectroscopy in a form factor that can fit inside the body of a phone has also been demonstarted that uses inexpensive components and the same kind of LEDs being used for flash illumination in phones. By adding a special component attached on top of a conventional smartphone image sensor, the researchers were able to measure the light absorption of liquids, and the scattering spectrum of solids. 

"We have had several projects where we looked to use the sensing capabilities of smartphones and mobile devices for point-of-use biomedical tests or tests that could be performed away from the laboratory," Cunningham explained. "But in all the projects that we've worked on so far, there has been a cradle or some instrument that the phone has to be in contact with to perform the measurement."

However, their latest paper, "Integrated spectroscopic analysis system with low vertical height for measuring liquid or solid assays" published in Sensors and Actuators B details how a smartphone could directly be placed over a cartridge containing the liquid to measure the specific color of the liquid. The results could then be directly sent electronically to a physician, who could make a diagnosis and suggest a remedy without a patient needing to see that physician in person.