In this blog post, we will take a look at how ray tracing achieved photorealistic images and became the core of next-generation technology.
Ray Tracing
The movie Avatar, which grossed $2.7 billion worldwide, is more than just a movie. This movie surprised many people not only because of its content, but also because all the images in it were created using computer graphics. The realistic images, which looked as if they were taken directly from an alien planet, elicited gasps from many people. This realistic visual expression is an example of a dream that has been realized, in which scenes that only existed in human imagination are made to appear as if they were real. Computer graphics technology has a short history of just over 50 years, but it has made rapid progress in keeping pace with the development of computers.
The development of computer graphics is not limited to the film industry, but is widely applied to various fields such as games, virtual reality (VR), and augmented reality (AR). These technologies go beyond providing visual enjoyment and play an important role in solving real-world problems, including in education, healthcare, and scientific simulations. In particular, the success of avatars has been an important turning point in the transition of computer graphics from a simple aid to a means of achieving an innovative combination of art and storytelling.
Computer graphics engineers have been trying to solve two main questions for a long time. The first is “How can we make things look more realistic?” and the second is “How can we process images faster?” The method that focuses on making things look more realistic is ray tracing, and the method that focuses on speed is scan conversion. In this article, we will focus on the ray tracing method for more realistic computer images.
How computer images are stored
Before understanding the ray tracing method, it is necessary to first understand how a computer stores images. If you have ever done a mosaic in art class, you can easily understand how to save a picture on a computer. A mosaic composed of squares like a checkerboard is similar to how a computer picture file is stored. The color of each of these squares corresponds to a number, and the image file is created by storing these numbers in order. This method is simple and has the advantage of high image quality, but it also has the disadvantage of taking up a lot of space. In the past, it was difficult to store high-definition images because computers were slow and had little storage capacity, but today, computers have sufficient capacity and speed, making it easy to store images in this way.
Principle of the ray-tracing method
The ray-tracing method is a method of creating an image by tracing the path of light. Here, it is generally assumed that the virtual light originates from the eye. In reality, light comes out of a light source, is reflected off an object, and then enters our eyes, but the ray tracing method calculates this in reverse. This is because it is difficult to predict where the light from the light source will go, and it is necessary to calculate all directions, so it is more suitable to calculate in a way that starts from the eye for efficiency. This method allows us to obtain images more efficiently by only calculating the scenes we actually see.
The specific method of the ray tracing is as follows. A virtual ray of light that starts from the eye is traced in a straight line until it reaches a specific object. When the light hits the object, the color of the object is stored and the path of the reflected light is also calculated. The light is reflected each time it hits an object, and this is repeated to add the color of the object as if it were being painted over, and the image is finally completed. The color of each point is calculated in this way to create an image.
The advantage of ray tracing is that it can produce highly realistic images. It can precisely simulate real physical phenomena such as reflection, refraction, and shadows, resulting in highly precise images. However, this precision also has the disadvantage of taking a long time to calculate. In many cases, a computer needs to run calculations for several hours to render a complex scene.
Speed Issues and Solutions
Graphics processing units (GPUs) were introduced to solve the speed issues of ray tracing. In general, the CPU is responsible for the computer’s calculations, but the GPU can process more calculations simultaneously through multiple computational devices. Since ray tracing needs to calculate the colors of many points, GPUs with this multi-computational structure are very advantageous. Therefore, it has recently become common to use GPUs to process ray tracing faster.
Recent studies are developing various methods to further speed up ray tracing. In particular, methods that optimize the storage of objects to calculate colors faster are attracting attention. In the future, it is expected that more efficient use of GPUs and more accurate simulation of the physical properties of objects will enable faster and more realistic images.
The Future of Computer Graphics Technology
Ray tracing is widely used not only in movies and games, but also in next-generation technologies such as virtual reality (VR) and augmented reality (AR). In particular, users of VR devices require high-quality graphics processed in real time for an immersive experience. Ray tracing will play an important role in driving the development of future graphics technology as it is increasingly combined with real-time processing technology.
In addition, there is a high possibility that a more efficient and faster graphics processing system will be developed by combining artificial intelligence (AI) and machine learning technologies. This will provide us with a much more immersive visual experience. Furthermore, we will enter an era where we will experience realistic scenes that we have only seen in movies or games in real time in our daily lives.
