Imaging system for leak detection

An imaging system and method for leakage detection uses schlieren imaging to locate and characterize a flow of pressurized gas with a refractive index different than ambient air. In particular, a schlieren imaging system includes a collimated light, a knife-edge spatial filter and a 4F telescopic imaging system is used to create an image of a device under test (DUT). The DUT is pressurized and monitored for leaks. When a leak is present and in the monitored plane of the DUT, contrast variation illustrates the presence, location and character of the leak. For example, a waterproof/leakproof mobile device may be evaluated for leakage between layers of modules, such as leaks in the housing of a waterproof electronics case. This detection can allow identification and characterization of the leak point via visual identification.