This plugins computes and draws contour lines on top of a 2D sequence. Additionally, it can print level labels next to the contour lines.
The contouring algorithm is a port to Java of the code found in the GIST package, also used by other plotting tools like Matplotlib.
Once installed, open the plugin by clicking on its icon in the "Plugin" workspace. Also open an image to use the plugin on.
Choose the number of levels to draw, and the min/max level values. In the example below, the image data goes from -0.4 to 0.4 roughly, and we have chosen to draw 13 levels from -0.35 to 0.35.
Sometimes displaying the contours on the whole image domain is not satisfying. In the above example, the interesting data lies inside a region at the center of the image, while the exterior intensities are zero. To remove the exterior from the contour display, we can use a mask sequence, of the same dimension as the original image, where the data is zero in the exterior region and non-zero in the inside region where the contours should be computed and displayed.
Finally, it may be desirable to show labels to indicate the level values. To do so, enable the checkbox "Print levels lavels" and choose a satisfying fontsize.
You may uncheck the "Remove previous contour painters" option to draw several contours with different parameters (different masks, labels for only a subset of levels, etc.). Every contour set is a layer that can be hidden, shown again, or deleted in the Icy's "Layer" pane.