Line integral convolution

Line Integral Convolution (LIC) is a Scientific Visualization technique proposed by Brian Cabral and Leith Leedom to visualize flows, like for example the wind movement in a tornado. Compared with classical Integration like techniques it has the advantage of producing a whole image at every step.

Principle

Intuitively spoken, we somehow visualize the flow of white paint that we spoiled on a vector field.

Algorithmically, we generate a gray level image of random pixels directly at the desired output resolution. Then for every pixel we calculate the forward and backward streamline of a fixed arc length. The average of all the pixels that lie in this streamline is the value assigned to the current pixel in the output image.

The output image will normally be colored in some way. For the tornado example the LIC output could be the lightness of the color and the vector length at every point could give the hue.

References

• [1], tutorial including a lot of sample pictures