Re-Referencing and Calibration for Robust Ratiometric Light Intensity Measurement

Point-of-care (POC) medical devices have become very popular to help diagnose and monitor health conditions without the need for specialized staff or attendance at medical centers. A large portion of these devices use light intensity-based measurements; however, the accuracy and repeatability of these measurements are affected by variations both within and between devices. Therefore, a universal method for device calibration and ratiometric measurement is presented which can provide a robust ratiometric light intensity measurement. The method can be applied to different light intensity measurement devices which utilize different sensor types, such as CMOS cameras or photodiodes (PDs). Results show that the method is able to produce a more accurate and repeatable ratiometric measurement when exposed to variations in both the intensity of the light source and the sensitivity of the sensors used to capture the light intensity.