In this paper two connectionist models for mid-level vision problems,
namely, edge and line linking, have been presented. The processing ele
ments (PE) are arranged in the form of two-dimensional lattice in both
the models. The models take the strengths and the corresponding direc
tions of the fragmented edges (or lines) as the input. The state of ea
ch processing element is updated by the activations received from the
neighboring processing elements. In one model, each neuron interacts w
ith its eight neighbors, while in the other model, each neuron interac
ts over a larger neighborhood. After convergence, the output of the ne
urons represent the linked edge (or line) segments in the image. The f
irst model directly produces the linked line segments, while the secon
d model produces a diffused edge cover. The linked edge segments are f
ound by finding out the spine of the diffused edge cover. The experime
ntal results and the proof of convergence of the network models have a
lso been provided.