Radiography is usually the method of choice for the detection of hidden design details and discontinuities in art objects. However, infrared reflectography (IRR) and other techniques, such as IRR coupled with multi/hyperspectral imaging, are now equally important for the detection of overpaint, changes, and general pigment distribution. To maximize information extraction from the images, as well as attempt to optimize the operators’ image interpretation, the noise of the system should be minimized. The development of effective image noise removal techniques within both the spatial and frequency domains is an important research area in industrial radiographic testing. In this study, the dual-domain image denoising technique was used to improve hidden design details and discontinuity visualization from art object radiographs. The technique relies on generating the low and high frequency components of the image through bilateral filtering and removing noise from the low contrast component using the wavelet shrinkage technique. The proposed algorithm was successfully applied to radiographic images of cultural heritage objects. Improvements in the design detail visualization and discontinuity region detections were achieved while preserving object edge and fine detail imaging information. Improvements in the visualization of detailed design and discontinuities were observed while preserving the overall quality of the image with respect to contours and fine details on the surface of the objects. Evaluation of the collected images demonstrated that design details obtained using the dual-domain reconstructed images were better visualized. Experts reviewed opinions gathered from Level II radiography certificate holders. These experts showed that design details from the dual-domain reconstructed images were better visualized than from the original images. Different discontinuities were also better detected by the application of the technique to the images. The evaluation of the image quality enhancement shows that the pixel intensity increases almost four times through the proposed technique.
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