All the colours of the rainbow
A breakthrough by a research team in Hong Kong is set to allow colour blind people to view almost all natural colours on screens.
The colour blind Aussie businessman was completely unprepared for what happened when he walked into the electronics fair and donned a pair of special glasses. For the first time in his life he could distinguish the colours red and green. Peter Marragg has suffered from colour blindness all his life.
What made the experience even more important to him was the knowledge that from now on he could see those colours through the glasses, while enjoying a movie or a television program with his family, who are not colour blind.
Computer and engineering scientists at the Chinese University of Hong Kong (CUHK) made the breakthrough that opens up a whole new on-screen world of almost natural colour for people like Marragg.
The breakthrough comes from manipulating the colours that often bedevil colour-deficient people onto two separate screens. The colours are reorganised on those screens to make the colour distinctions easier to recognise for people with colour blindness. The device has no effect on people with normal vision. They see the screen as they normally would.
"Red and green used to appear as the same colour to me," Marragg said, "but now I can easily distinguish the differences."
The application, developed by computer scientist Samuel Shen Wuyao and his team, can be installed on any regular 3D display device. Colour blind football fans now can distinguish between the colours of players' jerseys.
The problem for colour blind and colour-deficient people begins with the light receptors of the eyes — the rods and cones — which transmit information from the eyes to the brain.
The ability to distinguish colour resides in the three different types of cones in the human eye. Generally speaking the cones are sensitive to red, blue and green, respectively.
Colour blindness is a condition usually inherited through a faulty gene in the X chromosome from the mother. Because females have two X chromosomes, they usually compensate for deficiency in one, thus the vast majority of people affected by color deficiency are men.
The problem with colour blindness is that the light-sensitive cones of the retina function at "below normal" sensitivity. Those afflicted with the deficiency are unable to discriminate between colors.
The most common type of colour blindness, for example, is red-green colour deficiency. Some people suffer from blue-yellow colour blindness. People at the extreme end of colour blindness can see only black and white.
The different colours we see are distinguished by their wavelengths on the electromagnetic spectrum, of which the visible spectrum is but a small part. The variability of the wavelength determines the colours people see. People with defective vision cannot perceive the "just noticeable" differences by which colours normally are perceived.
Although there is currently no cure for colour blindness, the CUHK application provides color enhancement. The CUHK team developed an application that produces a pair of virtually identical images and displays them on the viewing device. The separate images are re-colored to emphasize the differences.
According to the type and severity of the patient's colour blindness, each image can be re-colored into hues and colour saturations making the distinction clear.
The singular images we see combine the images picked up by the left and right eye. Seen through a pair of regular 3D glasses, each eye of the colour blind patient receives only one of the two re-colored images. When the image is viewed as a single object by the brain, colour blind people are able to distinguish the colours.
Shen and his team started research on the visual technology five years ago, when he learnt that colour-blindness in Hong Kong was much more prevalent than he believed. Around the globe, it's estimated 250 million people have colour deficiency.
"A very large number of people have problems distinguishing colours when they do day-to-day work, using computers, for example, which limits their choices of occupation," he said.
To enable colour-blind people to distinguish colours, scientists had to understand how colour is perceived in the brain and simulate the process. That meant collating information from a variety of colour-blind people over a long period of time.
Shen has expressed his confidence that the application can be used in movie theaters, home television screens, mobile device screens, as well as wearable equipment, and would benefit many in the community.
Many major corporations, including Apple and Samsung, have expressed their interest in cooperating with the team, to make it easier for colour-blind users to see the screen.
"We, as scientists with rich knowledge and experience on colour enhancement, should do something to help make a difference," Shen said.
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