Research And Realization About Progressive-Simplification Based Vectorization On Well Log Graph

Vectorization, i.e. raster-to-vector conversion, is the process of analyzing the scanned image of an engineering drawing in paper form and recognizing the graphic objects in the drawing, and finally, generating the vector format file. Well log graph, discussed in this paper, is a kind of engineering drawing, which are used for oil and natural gas exploitation.Oil and natural gas are both important energy and precious chemical resources, so it is not surprised that all the countries pay special attentions to their oil exploitation. A part of the key work of each oil field is to take full advantages of the well log curves on graphs, analyse and extract the information contained, and store them properly. The oil field, named Daqing, spent much money on software and computer equipment----SUN Workstations. Then they spent a few years, finished only little part of the work. The main aim was at vectorizing the well log curves applying foreign software. The main tool is a mouse. How to vectorize the information rapidly and correctly remains to be an emergent unresolved problem.To solve the problem, this paper tries to design software for automatic vectorization, according to different characteristic of kinds of graphic. For example, Well computer drawing's back grids and well curves intercross frequently, and their gray are near. At the same time, grids are skimble-scamble, and so on. We introduce a new vectorization model-"Progressive-Simplification based Vectorization model"and bring forward a layered-tracing vectorization method for curves. Furthermore, after vectorization, we do some research on the important technique of graph redrawing. Among these key technology are as the follows:1. A method for extracting the back grids based on spatial recognizing, including the method of step point based cross matching and Hough transform.2. Pre-processing method for curves, including Laplace operator, morphologic operator and human-machine interaction.3. Tracking algorithm for curves, including the method for gray threshold combining space information, lag structure which was used to compress well-logging data during Compressing and a progressive-completing method for curves tracing.4. Graph redrawing, including sliming curves and compensation for peak value...