Seeing in colour is not a black-and-white business, advises Derek Powell, discovering how Samsung is helping people with colour blindness to see true blue (as well as true reds and greens).
Some levels of colour blindness can now be fixed by your television.
Colour blindness is the umbrella name for a range of conditions that affect a surprising number of people. Many individuals with moderate forms of this condition remain undiagnosed, and there is currently no treatment for inherited colour blindness. But two recent technologies are offering fresh and surprising possibilities — a new window on the world for those with this condition.
In Australia, around one in 12 men and one in 20 women will have some impairment in their ability to distinguish the full range of colours. Worldwide, it is estimated that around 300 million people may have colour vision deficiency (CVD). CVD can prevent people from entering certain professions — pilots and commercial drivers, for example, need to be able to interpret colour correctly to react to everything from traffic lights to cockpit warning indicators; they commonly have to pass a colour blindness test before receiving a licence. Electricians also need to be able to accurately discern active, neutral and earth wires based on colour alone, and there are a number of other roles in the armed forces where lives can be in danger if people cannot correctly recognise objects or indicators based on colour alone.
Our modern reliance on screens in everything from phones and computers to multifunction displays in vehicles has broadened the range of situations in which colour perception difficulties can cause problems. The inability to accurately perceive hues can make it hard or impossible to discern some shades of text over coloured backgrounds on screen. Similarly, interpreting coloured graphics and navigating various user interfaces can be quite difficult.
Fortunately, some of these same screens, on smartphones and TVs, are now able to make life a little easier for those with colour vision deficiencies. Colour coning This is achievable because the way our eyes perceive light has many similarities to the way that colour displays work. In the eye, there are two types of sensors that react to light. Rod cells are quite sensitive, and react like
black-and-white film, seeing the world in shades of grey. Cone cells are our eye’s colour sensors and are of three types, sensitive to red, green or blue light respectively. Our brain uses the signals sent by the different cone cells to distinguish the colour of objects. A red object will primarily stimulate the redsensitive cones; a yellow object will produce a nearly equal stimulus in both the red and green cones, and so on. The eyes have it Normal colour vision is called trichromacy, where the three types of cones operate correctly to accurately distinguish the range of hues from reds through greens to blues.
Anomalous trichromacy occurs when one type of cone has a reduced sensitivity. A reduced sensitivity to green light (known as
deuteranomaly) is the most common form of colour blindness; with reduced sensitivity to red ( protanomaly) the next most common.
Tritanomaly, reduced sensitivity to blue light, is the third form, and is comparatively quite rare. The amount of reduced sensitivity can
vary quite a lot, ranging from almost normal colour vision to cases where the person cannot at all perceive light in the red or green or blue parts of the spectrum. Like the eye, a colour video camera has red, green and blue sensors, with the whole range of colours reproduced on screen by emitting more or less light from red, green and blue pixels, normally balanced to provide proper colour reproduction. To a certain extent you can simulate the effects of protanomaly, deuteranomaly and tritanomaly by going into the menu of a computer monitor and turning down respectively the red, green and blue channels. Presuming you have normal colour vision, if you turn down the red, the resulting picture will look something like the world view of someone with protanomaly. Turning the red right off would somewhat simulate the condition of protanopia, the condition where the person’s red cones are absent altogether (the resulting spectrum corresponds to the colours in the largest circle above left). I don’t want to push this analogy too far, since colour vision deficiency can be much more complicated, but it is useful to understand the possibilities that technology can now bring. Most people are able to function really well with mild or moderate colour blindness, and many remain unaware of the limitations in their own vision. Proper diagnosis involves a variety of tests, often including the Ishihara Plate test. This test uses specially printed graphics with a background of coloured dots that contain numbers picked out in different hues (right). People with various types of colour vision deficiency will be unable to make out certain of the coloured numbers against particular backgrounds.
Vision of the future
To be useful, the printed graphics must have extremely accurate colour printing. Generally, uncalibrated colour monitors couldn’t be guaranteed to reproduce these graphics with sufficient accuracy for a reliable test. But the newest technology smartphone screens can be manufactured to such precise tolerances that they can reproduce Ishihara-style graphics closely enough to provide a useful (though not fully diagnostic) test for colour vision deficiency. A couple of apps have been developed to help address CVD for phone and computer users (including the useful Color Blind Pal for Android, iOS and Mac). Then late last year Samsung announced that it has gone even further, bringing this technology to a much larger canvas.
Samsung has taken a very scientific approach here, working with Professor Klara Wenzel from the Department of Mechatronics, Optics and Mechanical Engineering Informatics at the Budapest University of Technology and Economics. Professor Wenzel leads a team that developed Colourlite Test to accurately diagnose the kind and degree of CVD.
Working with Samsung, the Colorlite team adapted the test* to become an app that can be used on any Samsung Galaxy Note 6 (or later) mobile phone. It is called the ‘SeeColors’ app, and it is able to diagnoses deficiencies in colour vision on-screen. The app was first released some time ago to Hungaria, Romania and Bulgaria but is now available more widely, including via download through Samsung’s dedicated App Store, thereby opening up a new and amazing possibility for those with CVD to experience true colour vision for the first time — on their television. Here’s how it works. First, the user runs the app on-screen and takes the test, responding to each of the graphics that appear. Once complete, the app produces a personalised result that records the type of deficiency (such as deuteranomaly, protanomaly or tritanomaly) and, crucially, gives a number which signifies the degree of impairment. In the next step, the user can instruct their Samsung TV to recalibrate the screen, adjusting the colour balance to precisely counteract the deficiency revealed by the test. If the test indicates a reduced sensitivity to red, *You can try out a simplified form of this test online via www.avhub.com.au/colorlite for example, the screen will boost the red hues to precisely compensate for the lack of sensitivity in the person’s red cones, revealing a range of hues that they just couldn’t discern otherwise.
It is a little more complex that my description would suggest, but still, the idea is so simple that you might well ask why has no-one thought to do this before. There’s a very good reason. Turning up the red channel of an ordinary TV or computer monitor will simply saturate that channel, crushing the contrast without making colours brighter. With conventional screens, the RGB channels normally work near their maximums. While the colour channels can easily be turned down, they simply don’t have the dynamic range to be made significantly brighter. But the higher ‘nit’ levels of today’s high dynamic range (HDR)-capable TVs, such as Samsung’s QLED range, do have the brightness in reserve on each colour to be turned up far enough to make a difference.
But does it work? I can’t easily tell, as I have normal colour vision, so I called a contact at Samsung Australia. We were told that the app had caused some excitement in their office, with a pair of brothers who suffered from the common red-green colour vision deficiency volunteering to try it out. They both reported exciting results, commenting that the correction made a great difference to their viewing experience, even making faces clearer due to the improved skin tones.
There are a couple of limitations, of course. The app needs an HDR TV with QLED technology to operate, and it won’t help someone who has a complete absence of red, green or blue cones — though thankfully that is a relatively small proportion of those with CVD. Also, the recalibration is, of course, really only useful for solo viewing. Once adjusted for someone with significant CVD, the picture will look appalling and un-natural to someone with normal vision.
Despite these niggles, here’s a really good story of how modern display technology, designed to make things a little more real for everyone, can open a truly amazing window on reality for millions of people with CVD.
TRUE COLOURS: the circles represents the colour spectra perceived by people with normal vision (le), protanopia (large circle), and tritanopia (bottom). RIGHT: Samsung’s ‘SeeColor’ app.