Figure 2. Touching axons creating a false axon.

The fluorescent pictures are bicolored: the background is black and the structures are indicated with a specific color, e.g. red. In this figure, 3 axons (i) nearly touch, creating a semi-closed space (a), which might be interpreted as an additional axon using an automatic segmentation routine due to its color. The automatic segmentation of light microscopy images has therefore not only relies on color but also the shape features of the structure.