Enhancing Digital Core Image Resolution using the Optimal Upscaling and Downscaling Algorithm Based on Paired Scanning Electron Microscope Images

Summary The porous media community extensively utilizes digital rock images for core analysis. High-resolution (HR) digital rock images that possess sufficient quality are essential but often challenging to acquire. Super-resolution (SR) approaches enhance the resolution of digital rock images and provide improved visualization of fine features and structures, aiding in the analysis and interpretation of rock properties, such as pore connectivity and mineral distribution. However, there is a current shortage of real paired microscopic images for SR training. In this study, we used two types of scanning electron microscopes (SEMs) to obtain the images of shale samples in five regions, with 1X, 2X, 4X, 8X, and 16X magnifications. We used these real scanned paired images as a reference to select the optimal method of image generation and validated it using enhanced deep SR (EDSR) and very deep SR (VDSR) methods. Our experiments demonstrate that the bilinear algorithm is more suitable than the commonly used bicubic method for upscaling and downscaling low-resolution (LR) images, establishing image data sets in SR approaches. This preference is partially attributed to the operational mechanisms of SEMs.