Active Thermography Using Cellphone Attachment Infrared Camera

Active thermography (AT) is a widely studied non-destructive testing method for the characterization and evaluation of biological and industrial materials. Despite promising applications of AT in industry and medicine, commercialization and wide-spread adaption of AT has long been impeded by the high cost (usually $10k-$100k) and large size of infrared cameras. In order to overcome these limitations, in this thesis, we aim to demonstrate feasibility of performing AT with cell-phone attachment infrared cameras with cost of -$250 and size significantly less than the research-grade infrared cameras. This involves developing a hardware-level code/software for controlling camera attributes in order to achieve stable acquisition of frames at high frame rates. Given the importance of portability, we also demonstrate possibility of developing a setting that is both portable and easy to set up The nominal frame rate of camera through its standard applet is less than 9fps. In order to achieve higher frame rate, we utilized USB 2.0 documentation and Microsoft Windows native application programming interfaces to set up packets of information. These packets of information were then sent to the cameras default endpoint address and, subsequently, acquire frame data from camera through a corresponding pipe. As such, the developed platform has not only the ability to control camera attributes (e.g., calibrate camera, acquire frame, etc) through a simple USB interface but also can achieve a stable high frame rate of 33fps through a circular buffer hierarchy and multi-threading. To demonstrate performance of developed low-cost and portable system, two series of AT experiments were conducted: (i) in response to the recent legalizations of marijuana in Canada, we interrogated the photothermal responses of commercially available oral fluid lateral flow immunoassays (LFIAs) with the developed system. The results of our low-cost setup represent that it can reliably detect THC concentrations as low as 2ng/ml in oral fluid with 95% accuracy. (ii) To demonstrate ability of the system in early detection of dental caries, artificially-induced caries were imaged using the low cost and portable system. Our results suggested the ability of the developed AT low cost system for detecting early dental carries.