Abstract：Fluid inclusions(FI) are widely spread in microcracks and composed of fluid inclusion planes(FIP) and fluid inclusion lines(FIL)—the intersections of FIP with some observed planes. These microscopic compositions(FI) or structures(FIP and FIL) with different geometrical and configuration parameters may record the history of deformations and/or fractures in rocks. The original images are obtained from a camera on a heating-freezing stage. These images are first transformed into gray images and broken into blocks by image segmentations. For each block，the inflection point，derivative and color-based methods are all used to detect the edges for each fluid inclusion. The Roberts，Prewitt and Sobel algorithms are used in the inflection point. The LOG and Canny algorithms are used in the derivative method. In order to get better boundaries，the mathematical morphological analyses are used to extend edges，connect discontinuous points，fill pores in outlines，eliminate irrelative parts，smoothen projecting parts and aggregate the smaller inclusions into big ones. The inflation，erosion，seed-filling，boundary connection，smoothening methods are used in the mathematical morphological analysis. After re-orientation for each block，edge points and lines are ascertained in the global coordinate system. According to the geometrical properties of inclusions from edge detection，especially from the mathematical morphological analysis，FILs and their configuration parameters are finally obtained with the least square method. The geometrical properties include positions，areas and long-axis directions. The configuration parameters include length，and width. All of these procedures are coded into a program. Due to the reflection of FIL on the characteristics of microcracks and the formation relationships between the micro- and macro-structures，the analysis presented here may theoretically provide a good foundation to reveal the micromechanics of the change process for different geological phenomena in rock area.
