Enhancement of Ultrasonic Images of Defects in 3-D Composite

Abstract

Image enhancement and analysis methods are applied to ultrasonic C-scans of stitched, resin transferred molded 3-D composites to make their quality for visual determination of the amount of porosity defect equal to that for 2-D composites conventionally fabricated from prepreg. The application of these methods is necessary because the 3-D reinforcing fiber architecture, along which the porosity tends to form during fabrication, is also imaged in the ultrasonic c-scans, thus severely limiting the visual determination of the amount of porosity present. Comparisons are made of the C-scan images of a stitched panel before and after the application of image enhancement and analysis methods to demonstrate the value of the methods. The importance of the number of shades of gray in the image for visual interpretation of defects and for the application of the enhancement methods is also discussed.