Japanese researchers said Saturday they have developed a humanoid robot that can laugh and smile as it mimics a person's facial expressions.

The robot, Geminoid TMF, can move its rubber facial skin to imitate a smile, a laugh showing teeth, and a grim look with furrowed brows, by receiving electric signals from the person it is modelled on.

The researchers demonstrated with a robot made to look exactly like an attractive woman in her 20s with long dark hair. The woman and the robot were dressed in the same clothes - a black skirt and black leather jacket.

The robot smiled and furrowed its brow in almost simultaneous mimicry of the woman, whose face was filmed with a video camera which then provided information on her expressions to the robot through electric signals.

"I felt like I had a twin sister," the woman told reporters afterwards.

The developers said they expected the robot to be eventually used in real-life situations, for example in hospitals.

"We've already got some data showing that the robot gave patients psychological security by nodding and smiling at them, when patients were checked on by doctors," said Satoko Inoue, spokeswoman for Kokoro, one of the two companies involved in the development.

"A new technology always creates some fears and negative opinions," but the researchers wanted to make robots that could express something similar to human emotions, said Hiroshi Ishiguro, a professor at Osaka University who led the research.

Copies of the robot are expected to be sold for about 10 million yen (110,000 dollars), mainly to robotics research organisations, Ishiguro said, without giving a timeframe.