3D reconstruction and characterization of reef limestone pores based on optical and acoustic microscopic images

The pore network in reef limestone provides an important resource for fluid storage and flow. Three-dimensional (3D) reconstruction and characterization of the spatial structure of reef limestone pores offers a valuable way of identifying its physical and mechanical properties. This paper reports on a study where optical and acoustic microscope images were used to combine the advantages of the high resolution of optical testing with the high penetration capabilities of acoustic testing. This overcomes existing problems with multi-scale structural imaging of the pores in reef limestone caused by the small penetration depth of traditional optical imaging and the low resolution of ultrasonic imaging. First of all, a correlation function between the shallow and deep pore structure of reef limestone is established. This draws on high-resolution data from shallow optical microscopic images and deep acoustic microscopic images with a multi-layered cross-section. The contours of the shallow and deep pore structure are then digitized. After this, horizontal section control points and vertical transition contours are constructed that enable a deep integration of information about the multi-dimensional geometric morphology of the pore structure to be realized, providing in turn for a fine-grained 3D reconstruction of the pore structure at different scales. Finally, factors governing the characterization of contour similarity and center deviation are proposed that make it possible to generate spatial representations of the pore structure across multiple dimensions. A real-world case analysis is then used to verify the feasibility and reliability of the proposed method. The results show that the method can provide abundant data for the establishment of a reef limestone pore network and physical model, making it possible to improve the quality of 3D reconstructions of the pore structure and improve the 3D imaging of reef limestone pore networks. The proposed method can underpin new approaches to analysis of the pore structure of reef limestone and support a wide range of potential applications in the field of pore visualization and characterization.