Ray tracing is a computer graphics technique that traces the path of light to create photorealistic images. It uses GPUs to solve speed issues and is playing a key role in next-generation technologies such as VR and AR. It has great potential to be combined with AI.
Ray Tracing
With $2.7 billion in box office revenue worldwide, Avatar is more than just a film. The film stunned many people not only for its content, but also for the fact that all of its visuals were created with computer graphics. The realistic visuals, which look as if they were actually filmed on an alien planet, are a dream come true for humans to create scenes that existed only in our imagination. Computer graphics technology has only been around for about 50 years, but it has come a long way in leaps and bounds to keep up with the pace of computer advancements.
Advances in computer graphics aren’t just limited to the film industry, but have been applied to a wide range of fields, including gaming, virtual reality (VR), and augmented reality (AR). Beyond providing visual entertainment, these technologies are also playing an important role in solving real-world problems in education, healthcare, scientific simulations, and more. The success of Avatar, in particular, marked a turning point in the evolution of computer graphics as more than just an auxiliary tool, but as a means to create innovative combinations of art and storytelling.
Computer graphics technologists have long been trying to solve two main questions: ‘How can we make images more realistic?’ and ‘How can we process images faster?’ Ray tracing is the method that focuses on realism, and scanning is the method that focuses on speed. In this article, we’ll focus on ray tracing for making computer images more realistic.
How computer images are stored
Before we can understand ray tracing, we need to understand how computers store images. If you’ve ever done a mosaic in art class, it’s easy to understand how computers store pictures. A mosaic, made up of squares like a checkerboard, is similar to how computer picture files are stored. Each square has a colour corresponding to a number, and the picture file is the result of storing them one after the other. This has the advantage of simplicity and high quality, but it also has the disadvantage of taking up a lot of space. In the past, computers were slow and had little storage capacity, which made it difficult to store high-quality images, but today, computers with sufficient capacity and speed make it easy to store images in this way.
How does ray tracing work?
Optical ray tracing works by tracing the path of light to create an image. Here, an imaginary beam of light is usually assumed to originate from the eye. In reality, light leaves a light source, bounces off an object, and then enters our eyes, but ray tracing works backwards because it’s hard to predict where light from a light source will go, and it would be necessary to calculate all directions, so for efficiency, it makes more sense to calculate from the eye. This way, we only need to calculate the scene we actually see, which results in a more efficient image.
Here’s how ray tracing works: an imaginary ray of light from the eye is traced in a straight line until it reaches a specific object. When the light hits an object, it stores the colour of the object and calculates the path of the reflected light. Each time the light hits an object, it is reflected back, and this is repeated over and over again, adding the colour of the object as if it were a continuous layer of paint, until the image is finally complete. In this way, the colour of each point is calculated to create the image.
The benefit of ray tracing is that it can produce highly realistic images, as it can accurately simulate real-world physical phenomena such as reflections, refractions, and shadows. However, this precision also comes at the cost of computational time. Complex scenes often require the computer to compute for hours to represent them.
Speed issues and solutions
Graphics processing units (GPUs) have emerged to solve the speed problem of ray tracing. While the CPU is typically responsible for computing on a computer, the GPU can handle many more calculations simultaneously by using multiple computing units. Since ray tracing requires calculating the colours of many points, this multi-computational structure is very advantageous, and it has recently become common to use GPUs to make ray tracing faster.
Recent researchers are developing a variety of ways to further speed up ray tracing, most notably by optimising the way objects are stored to calculate colours more quickly. In the future, it is expected that faster and more realistic images will be achieved by utilising GPUs more efficiently and simulating the physical properties of objects more accurately.
Future computer graphics technologies
Beyond film and gaming, ray tracing is also being widely applied to next-generation technologies such as virtual reality (VR) and augmented reality (AR). In particular, users of VR devices require high-quality graphics that are processed in real time for an immersive experience. As ray tracing is increasingly combined with real-time processing, it will play an important role in the future of graphics technology.
It’s also likely to be combined with artificial intelligence (AI) and machine learning techniques to create more efficient and faster graphics processing systems. This will give us a much more immersive visual experience than we have today, and we’ll be able to experience realistic scenes in real time in our everyday lives that we used to only see in films and games.
