In the results, the images are as follows:

1. original: Original
2. seg: Segmentation using Felzenszwalb & Huttenlocher algorithm
3. cluster: for each cluster of segments with more than 1 element, that cluster is colored a random color (segments in singleton clusters made greyscale)
4. pop: original image with segments in singleton clusters made greyscale.

original	seg	cluster	pop
bike-racks-and-windows
bollards1
dandelions
flowers
upson-floor-dots1