Direct Volume Rendering Of 3d Seismic Data, Field Of Study

There exists great limitation on traditional seismic data interpretation method, which shows seismic data sets by displaying the planar image of seismic section and horizontal slice. The advent of scientific visualization technology makes possible 3-D seismic data interpretation. Applying this technology to 3-D seismic sets announces the birth of 3-D seismic data visualization technology, which includes mainly two methods of surface visualization and direct volume rendering. In this paper, we will study ray-casting algorithm in 3-D seismic data sets, one of direct volume rendering methods.The general flow of ray-casting algorithm is: data classification and color assignment -ray tracing and data resampling -image composition. According to the flow, we have deep studied ray-casting algorithm in 3-D seimic data sets and given the specified scheme for realization each step. First, by knowing fully traits of seimic data processed, we put forward two methods of data classification based on equalization: the improvement of Median-cut algorithm and Dynamic Array Algorithm. Second, we select color scale and opacity curve as transfer function, give the index mapping method to reflect fast the adjustment effect of color and opacity. Considering image space transform, traits of seismic data and the correlation of data sets, we achieve the improved ray-casting algorithm. The steps includes: setting up the coordinates, finding and filling the projection polygon, computing ray function, calculating iteratively the sampling start points, intersecting slices, interpolating by bilinear relation, and early ray termination.Through these measures, the algorithm realizes the fast direct volume rendering with the aid of OpenGL technology, and gains faster and better results than traditional method.