The line integral convolution (LIC) method, which blurs white noise textures along a vector field, is an effective way to visualize overall flow patterns in a 2D domain. The method produces a flow texture image based on the input velocity field defined in the domain. Because of the nature of the algorithm, the texture image tends to be blurry. This sometimes makes it difficult to identify boundaries where flow separation and re-attachments occur. We present techniques to enhance LIC texture images and use colored texture images to highlight flow separation and re- attachment boundaries. Our techniques have been applied to several flow fields defined in 3D curvilinear multi-block grids and scientists have found the results to be very useful.
David L. Kao,
"Enhanced line integral convolution with flow feature detection", Proc. SPIE 3017, Visual Data Exploration and Analysis IV, (9 April 1997); doi: 10.1117/12.270314; https://doi.org/10.1117/12.270314