A technique for the application of composite patches for repairing metallic structures has been developed recently. In order to achieve to an effective repair, high-quality patches and bonding should be used. Various ultrasonic testing (UT) techniques, such as pulse-echo, are commonly used to check the patch and bonding. Ultrasonic measurements are associated with some limitations, especially for the multilayered structures, due to the presence of a significant amount of noise in the scan images. In order to enhance the UT images, various processing techniques can be employed. In the present research, different image processing algorithms based on morphology techniques have been adopted to enhance the C-scan images obtained from the ultrasonic measurement of five carbon/epoxy patches bonded to an aluminum plate. Twelve delaminations with various sizes and locations along with three disbond discontinuities were artificially embedded in the five patches. The processed and input images have been quantitatively compared to clarify how useful the utilized morphology processing algorithms can be. According to the comparison results, a morphology-based processing algorithm that is more useful than the others has been introduced.
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