Patent ID: 7388204

Claim:
A feature inspection system for inspecting a feature extending from a cavity within a structure to an outer surface of the structure, the feature inspection system comprising: a first gas of a first density adapted to flow over the outer surface around the feature; a second gas of a second density different from the first density and adapted to flow into the cavity and through the feature; an infrared camera comprising a lens and adapted to provide a thermal image of an area of the outer surface around the feature, the thermal image comprising an array of elements representing a plurality of temperatures; a generally annular piece sized to fit around the lens, the annular piece comprising gas discharge passages spaced around a periphery of the annular piece and in fluid communication with the first gas for directing the first gas over the area of the outer surface; and a control in electrical communications with the infrared camera and causing the first gas and the second gas to simultaneously flow over the outer surface and through the feature, respectively, and the control processing the plurality of temperatures to identify a qualitative characteristic of the feature.