A gadget to "translate" dog barks for humans, a "babypod" that plays music inside the mother's vagina for unborn babies and the world's first self-colonoscopy method were among the whacky inventions on show Friday at a new Tokyo exhibition.

The museum celebrates weird and wonderful inventions created by real scientists for the Ig Nobel Prize -- or "anti-Nobels" -- designed to make people "laugh first and think later."

Japanese medic Akira Horiuchi, 57, was among the winners last week of the tongue-in-cheek prize, organised by the satirical science journal "Annals of Improbable Research", for his do-it-yourself colonoscopy.

Horiuchi demonstrated his technique to AFP at the museum from his 2006 study "Colonoscopy in the Sitting Position: Lessons Learned from Self-Colonoscopy."

The researcher said he had never found his method embarrassing.

"I knew the importance of colonoscopy and that the number of colon cancer patients was increasing," Horiuchi told AFP.

The latest research shows that cancer of the colon is the most prevalent form of the disease among Japan's 870,000 cancer sufferers, according to the National Cancer Center.

"Not many people took the test... so I wanted to create an examination that would be accepted by everyone," said Horiuchi.

Another exhibit was the dog-language interpreter "Bowlingual", which classifies barks into six emotional categories -- frustration, menace, joy, sorrow, desire, and self-expression.

The babypod is a speaker inserted into the vagina that creates a "concert" for unborn children, after research showed this was more effective than playing music on the belly.

Japanese researchers have won Ig Nobel prizes for 12 years in a row. The winners include a team who developed Bowlingual and researchers who discovered female insects endowed with a penis.

Prize founder Marc Abrahams told reporters in Tokyo Friday that Japan had so many winners because there were "many eccentric people" in the country.

"In most of the world, when people behave in very eccentric ways, that's considered to be a very bad thing."

"In Japan and also in the UK, it's different," Abrahams said.

"You don't kill your eccentrics. You love them," he said, adding that is why Japan and the UK have long been "inventing so many clever, crazy, wonderful things."

Horiuchi agrees.

"I thought I was an eccentric. But I now know there are many people like me in Japan.