| 摘要 |
An improved leak detection system (10) of the differential absorption type is provided for identifying gas leaks in a test object (12), wherein the improved system (10) provides enhanced resolution and accuracy by compensating for the effects of background gases and the like along the image path. The system utilizes a video camera (18) to generate images of the test object (12) which has been pressurized with a selected gas (14) having strong absorption properties with respect to an illuminating light source (16) of a selected wavelength. Since the absorption bandwidth of the test gas (14) varies with temperature, the gas is preconditioned as by heating such that the temperature of gas leaking to the exterior of the test object (12) will vary with proximity to the test object. The camera (18) observes the pressurized test object in sequence through filters (30, 32) of narrow and broad bandwidth to generate a pair of images which can be electronically compared to isolate upon the test gas (14) located substantially at a specific leakage site or sites on the test object.
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