Image contrast enhancement algorithm for X-ray observation of space materials in situ

Abstract

Chinese Space Station has planned a high-temperature material science experiment rack, equipped with an X-ray projection imaging module, to support the development of material experiments and research in space. BiFeO3 has been selected as the first batch of experimental materials for Chinese Space Station. The melting and solidification process of BiFeO3, an opaque, high-temperature material, is observed by X-ray observation module in situ. X-ray is the dominant way to observe opaque materials due to its penetrability. In-situ observation of materials is the top priority of this study, so we have strict requirements on image quality, and high-quality images can better analyze the properties and properties of materials. Limited by narrow size and high temperature conditions, the X-ray images collected have low contrast, serious noise pollution, and poor imaging quality. To enhance the contrast and improve the edge details of such images, a grayscale weighted histogram equalization combined with high-frequency enhancement (GWHE-HFE) algorithm is proposed. First, we add a mask to the input image to obtain the region of interest (ROI), and then filter out the low-frequency components of the image by Gaussian high-pass filter to preserve high-frequency details. Second, the image obtained in the previous and the X-ray image of ROI are respectively multiplied by a coefficient and added to obtain the edge-emphasized X-ray image. And then, we use grayscale weighted histogram equalization (GWHE) to process the image obtained in the second step to obtain the contrast enhanced X-ray image. The enhanced image shows the crystal grains and the thin bands where the solid and the melt intersect, and it is helpful to accurately locate the solid solution interface. Experiments on X-ray images of BiFeO3 growth demonstrate that this combined method outperforms existing ones both qualitatively and quantitatively, providing an in-depth and effective analysis method for in high-temperature material-science experiments.

Vision-based measurement method for geometric dimensions of PVC pipe end faces

“…Numerous researchers have conducted extensive studies on various geometric dimension image measurement techniques for different workpieces, achieving significant breakthroughs [4][5][6][7]. Gong-Y and Seibel [8] utilized three-dimensional optical technology to gauge complex micro-surfaces, such as internal threaded holes, within machined parts.…”

Research on the Contrast Enhancement Algorithm for X-ray Images of BiFeO3 Material Experiment

“…Since the melting point of BiFeO 3 is 960 • C, it is not possible to obtain high-definition X-ray images using close-range transmission imaging. The molten BiFeO 3 sample should be kept at a certain distance from the X-ray source and the detector [14][15][16]. The imaging principles are illustrated in Figure 2.…”