A Development of Low-Cost Optical Image Device for Tuberculin Skin Test

Tuberculin skin test is done by measuring the maximum size of infectious area. Normally, it is done using a ruler and human eyes. Error can easily occur from this conventional measurement method as the infectious site is in millimeter scale. Different person could interpret different size of the area, which could lead to false diagnosis. To standardize the process, image processing along with optical imaging knowledge are used for creating a system that can determine the size of infectious area with least human action involved. A compact model based on low-cost USB camera and a software that calculates the size of an object in captured image are established. The whole system is tested with variation of samples, with 5 measurements repeatedly done on each sample to find the average size result. In the final stage, the system can properly measure out the redness area on the skin.