San Francisco on a foggy day.

(sff1): The original image.
(sff1sca1): Cropped grayscale version of the original.
(sff1can1): Result of edge detecting sff1sca1 using the Canny operator.
(sff1hou1): Hough transform space of sff1can1.
(sff1hou2): Reconstructed edges with peak value bigger than 70% of maximum peak from the Hough Transform in sff1hou1 superimposed on sff1can1.
(sff1hou3): Reconstructed edges with peak value bigger than 50% of maximum peak from the Hough Transform in sff1hou1 superimposed on sff1can1.