摘要
线积分卷积(LIC)方法是一种针对矢量场数据的可视化技术,本文主要研究了LIC方法应用于海洋流场的可视化质量改进问题。主要包括以下几点改进:根据海流运动方向改变稀疏背景噪声的指向以使流线变得更加细长明亮;针对稀疏噪声中海流变化剧烈的区域流线会出现分叉的问题,采用忽略稀疏背景噪声流线追踪时非主流线部分的纹理点的积分计算方法来解决此问题,同时可以省去不必要纹理点的积分计算的开支,加快显示速度;采用赋予海流随机的初始相位的方法来解决稀疏噪声循环动画突兀的问题;通过流线的运动速度快慢或者流线的颜色来表示海流速度大小;通过对海流数据进行插值并改善边界流线追踪条件的方法可形成完整细致的全球海流图像。实验结果表明,该方法可以生成纹理对比强烈、细节清晰、动画连贯的高质量海流运动图像,具有良好的可视化效果。
Line integral convolution(LIC) is a visualization technique for vector data. This paper mainly studies the visual quality improvement when LIC is applied to the ocean current field. Several improvements are made: the direction of background sparse noise is changed according to the direction of vector field in order to make the streamline more clear and bright; the pixels which the main streamlines do not pass are ignored to avoid the confusion by the dispersed streamlines, it can also save a lot of extra calculation of unnecessary pixels to speed up the operation; random initial phase for every streamline is provided to avoid the pulsation effect when using sparse noise as background noise during animation; the velocity is encoded in the speed of almost the same length streamline animation in order to express flow rate; moreover,display the velocity is displayed by the color of streamlines; interpolate ocean data and improve boundary streamline tracking conditions to form a complete and detailed global current image. The experimental results show that this method can generate high-quality ocean current images with strong texture contrast, animation continuity and clear details, and has good visual effects.
引文
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