  This paper describes an incoherent method to search for continuous
gravitational waves based on the Hough transform, a well known technique used
for detecting patterns in digital images. We apply the Hough transform to
detect patterns in the time-frequency plane of the data produced by an
earth-based gravitational wave detector. Two different flavors of searches will
be considered, depending on the type of input to the Hough transform: either
Fourier transforms of the detector data or the output of a coherent
matched-filtering type search. We present the technical details for
implementing the Hough transform algorithm for both kinds of searches, their
statistical properties, and their sensitivities.
