A hidden image has been discovered behind a historic Pablo Picasso oil painting.

The Art Galley of Ontario, where the painting is currently on display, teamed up with Northwestern University’s Centre for Scientific Studies in the Arts in Chicago to scan some of Picasso’s work with X-ray fluorescence spectrometry and other imaging technology.

Researchers revealed at the American Association for the Advancement of Science (AAAS) annual meeting they found Picasso had painted over another image by an unknown artist.

His painting from the blue period, La Miséreuse accroupie, also known as The Crouching Beggar or The Crouching Woman, was created in 1902.

Researchers used imaging technology to identify the underlying painting. Photo: Art Gallery of Ontario

Materials science and engineering professor at Northwestern University, Marc Walton, told AAAS it was known an underpainting existed, but nobody had identified it.

They believed there was an underpainting because of different paint textures.

The X-ray technology revealed behind the painting of The Crouching Beggar was a landscape image of Barcelona.

Professor Walton said Picasso had used some of the existing contours to create his painting.

The artist behind landscape painting is unknown. Photo: Art Gallery of Ontario

Researchers also found another layer between the original painting and Picasso’s finished product — an earlier version of The Crouching Beggar.

“This sort of information allows us to get inside the mind of Picasso, to understand his creative stances, to be able to get a better sense of his working style at this really critical period at the beginning of his career,” Professor Walton told AAAS.

One of the leaders of the project, Francesca Casadio from the Centre for Scientific Studies in the Arts in Chicago, told the BBC the discovery helped understand Picasso’s thought processes.

“Many more paintings are waiting to tell their secrets and with our scanning system we can help them talk to us more,” she said.

Researchers told the AAAS the X-ray fluorescence spectrometry device created grayscale pictures of chemical elements in hidden paints.

Using these elements they were able to create a recolouration of the original work.