Research Of Infrared Thermal Wave Non-destructive Testing Of Aircraft Engine Turbine Blades Crack

Turbine blades are the crucial heated end components of gas turbine engine, which have directly impact on the safety of engine. Because of the speciality of turbine blade materials and the high cost, several nondestructive techniques have been proposed and used for blades inspection tasks. For conventional in nondestructive testing methods, thermal wave nondestructive testing technique has been used to test cracks of turbine blades. The surface and subsurface structure information of specimen may be obtained through controlling the stimulation media actively and monitoring the temperature distribution of specimen.In this paper, hardware and application software of Infrared Thermal Wave Nondestructive Testing system are designed and improved, including heat-wave excitation source and the determination of incentives, as well as design and development of supporting control box; This article focuses on the improvement of application software and mainly reflected in the image processing algorithm research and improvement. In the infrared thermal image pre-processing sectors, the introduction of an assignment-based matrix and rough set indiscernibility sexual relations of PCNN image enhancement algorithms to enhance the image. Part of the crack in the image edge detection, this paper presents an improved method based on the level of center of gravity method underlined sub-pixel extraction method, the algorithm can determine the crack edge pixel coordinates to achieve the edge of the crack redraw.In this paper, two aspects are improved and innovated: First, aproposed a new image enhancement algorithm, which is based on the assignment matrix and rough set indiscernibility of PCNN infrared image enhancement algorithm for image acquisition on Infrared Image Enhancement , to achieve infrared image enhancement and denoising purposes. Noise image contrast is effectively enhanced and noise are contained in a large extent; Second, sub-pixel edge detection positioning method is proposed, which is based on the level of France underlined the center of gravity method, to achieved crack image. The results showed that the detection system can achieve the heat wave excitation, infrared image acquisition and image processing, precise posited the turbine blade cracks, and completed the design requirements.