Enhancement of Digital Radiographic Images for Gas Turbine Blades Based on Simple Scattering Model.

Digital radiographic imaging technique plays an essential role in the non-destructive testing of gas turbine blades. Due to the scattered X-rays in the detection of gas turbine blade, the quality of digital radiographic image is limited, and the effective information may be missed, which makes it difficult to characterize defects. Based on the simple scattering model and dark channel priori theory, an enhancement method for digital radiographic images of gas turbine blades is presented in this paper. Using the digital radiographic testing system, the proposed method is verified in the detection of uncooled 3rd and 4th stage gas turbine blades which is composed of nickel-based high temperature alloys. The experimental results show that the proposed method can dramatically enhance the visibility of digital radiographic images, including the improvement of contrast-noise ratio and sensitivity. In the meantime, the tiny defects that are not visible in the initial image can be identified and the detection can be more accurately characterized in the enhanced digital radiographic images. The proposed method can assist in de-scattering applications and improve the visibility of digital radiographic images without precise information about the X-ray condition. [ABSTRACT FROM AUTHOR]