"street-elbow.raw" is a raw image with 512 columns and 512 rows. The intensity
at each pixel is represented by one byte.

    street-elbow.canny.3.lbed keeps the data of these linked edges by using the
Canny edge detector and the linker based on locally constant curvature hypothesis.  

    street-elbow.dwbed.3.lbed keeps the data of these linked edges by using the
directional Wang-Binford edge detector and the linker based on locally
constant curvature hypothesis.

    To load the *.lbed files, you may take a look at the example algorithms
in io-functions.lisp and io-functions.c. lbed-format.ps explains some detail
about the data structure of lbed files.  You have to modify them
to fit into your purpose. 
    
    linked-edges-5.canny.ps and linked-edges-5.dwbed.ps show the linked edges
with length longer than 5.

    linked-edges-20.canny.ps and linked-edges-20.dwbed.ps show the linked edges
with length longer than 20.