# Research on Multi-Scale Fusion Method for Ancient Bronze Ware X-ray Images in NSST Domain
###### Abstract  
X-ray imaging is a valuable non-destructive tool for examining bronze wares, but the complexity of the coverings of bronze wares and the limitations of single-energy imaging techniques often obscure critical details, such as lesions and ornamentation. Therefore, multiple imaging is required to fully present the key information of bronze artifacts, which affects the complete presentation of information and increases the difficulty of analysis and interpretation. Using high-performance image fusion technology to fuse X-ray images of different energies into one image can effectively solve this problem. However, there is currently no specialized method for the fusion of images of bronze artifacts. Considering the special requirements for the restoration of bronze artifacts and the existing fusion framework, this paper proposes a new method. It is a novel multi-scale morphological gradient and local topology-coupled neural P systems approach within the Non-Subsampled Shearlet Transform domain. It addresses the absence of a specialized method for image fusion of bronze artifacts. The method proposed in this paper is compared with eight high-performance fusion methods and validated using a total of six evaluation metrics. The results demonstrate the significant theoretical and practical potential of this method for advancing the analysis and preservation of cultural heritage artifacts. image fusion; X-ray images of bronze wares; non-subsampled shearlet transform; multi-scale morphological gradient; coupled neural P systems +
Footnote †: journal: Medical  
This paper focuses on the X-ray imaging of Han Dynasty bronze mirrors. During the X-ray imaging process, the varying transmittance of X-rays in distinct areas of the bronze mirrors, specifically the decoration and rim areas, results in differences in brightness and darkness in the final image. Additionally, the optimal diffraction energy needed varies between the center and rim of the mirror due to their differing thicknesses. To acquire more comprehensive information about the mirror, it is necessary to capture images of different areas using varying levels of diffraction energy. As a result, multiple X-ray images of a mirror are often produced, which poses a challenge for heritage workers in analyzing and extracting information about the mirror. To improve the efficiency of cultural relics protection work, multiple bronze mirror X-ray image fusion using image fusion technology can present the information of the bronze mirror more clearly and comprehensively. Image fusion technology is widely utilized in cultural relic protection and research. Its primary principle is to enhance texture clarity, information reproduction, and detail richness of the target image by merging pixel data from the source image with the corresponding positions of the target image [3]. This process generates a more precise and realistic fused image, making it an ideal fit for most bronze ware pixel-level image fusion applications. Due to the unique nature of bronze wares, their digitized information is often not as extensive as that of other fields. As a result, traditional methods are predominantly used for the image fusion of bronze wares, with multi-scale transform (MST) being the most prevalent method in recent years [4]. The MST fusion method decomposes the image into high and low-frequency subbands using a transform and applies a specific fusion rule to merge them, and, finally, obtains the fused image by inverse transformation. Commonly used MST methods includes Wavelet Transform (WT) [5], Shearlet Transformation (ST) [6], Discrete Wavelet Transform (DWT) [5], Non-Subsampled Contourlet Transform (NSCT) [7] and Non-Subsampled Shearlet Transform (NSST) [8]. However, these methods are mostly applied in the fields of medical image fusion and infrared and visible image fusion. At present, there is limited research on bronze X-ray image fusion, with only the use of basic fusion frameworks.