The World's Ugliest Dog Contest will celebrate the inner beauty and imperfections of man's best friend on Friday evening at the Sonoma-Marin Fair in Petaluma.

The pooches — many of which are adoptable or previously adopted — will face off in a red carpet walk and "Faux Paw Fashion Show," organizers said. The contestants are judged on first impressions, unusual attributes, personality and audience reaction.

A blind Chihuahua-Chinese Crested mix named Sweepee Rambo bested 16 other homely hounds in last year's competition and walked away with $1,500, a trophy and a flight to New York for media appearances with her owner, Jason Wurtz. The then-17-year-old champion proved that third time's the charm after falling short in the competition twice before.

In advance of the competition, you can meet this year's contestants — though organizers note that voting is now closed and was for "entertainment purposes only and does not affect the outcome of the World's Ugliest Dog judging."

By celebrating inner beauty, organizers said they hope to showcase that all dogs, regardless of physical appearance, can be lovable additions to any family.

Contest rules prevent owners from intentionally altering their animals to enhance appearance for the purpose of the contest. These pooches are celebrated for their natural ugliness, organizers said.

Besides the main crown, the Spirit Award is presented to a dog and owner who have overcome obstacles or provide service to their community.

The competition has been held in Petaluma for more than 50 years.