Cornell Box	Cornell Box's lines
Cornell Box's edges	Cornell Box's Hough Transform

Figure 5: Results of applying entire algorithm to the Cornell Box

A building	A building's lines
A building's edges	A building's Hough Transform

Figure 6: Results of applying entire algorithm to a photo of a building.

A bunch of rectangles	Lines detected
Edge pixels detected	Hough Transform of the synthetic image

Figure 7: Results of applying entire algorithm to a synthetic image with just monochrome rectangles.

Zelda	Lines detected on Zelda
Zelda's edge pixels	Hough Transform of Zelda

Figure 8: Results of applying entire algorithm to an artistic image of Zelda


NOTE: Lots more images of my results and the intermediate steps can be found on my project web page at:
http://www.cs.utah.edu/~wyman/classes/imp/edge_detection/index.html