What Is 3D Computer Vision?

Three-dimensional (3D) computer vision is a method of using cameras that allows computers to emulate human vision to build a 3D image. With 3D computer vision, a computer uses two cameras at once — just like a person uses two eyes — to build an image with depth. Aside from its use in creating 3D images and movies with recording devices, 3D computer vision also is used frequently with robotics, allowing robots to capture true 3D environments. One of the major problems in developing this system was ensuring that the cameras were aligned correctly, but many systems have perfected this technique. This method also makes 3D technology cheaper for the consumer market, because expensive image processors are not required to build the 3D image.

For 3D computer vision to work, the computer needs to use two different cameras the way people use two eyes. Both cameras record or capture an environment from different angles, allowing the computer to use an algorithm to blend the images and form real-life depth. Computers also are able to capture real-time 3D images, without the need for much processing between the capture and 3D building. This makes 3D computer vision useful for the gaming, movie and recording markets.


Aside from using 3D computer vision to make images and movies, this method also is often used in robotics, especially with robots made to move around and interact with an environment. By using the two cameras, the robot is able to understand the depth of an environment, making it more adept at working with other objects and overcoming physical obstacles such as gaps and bumps. Robotic movement also is smoother because of this understanding of depth.

The major problem in creating 3D computer vision was aligning the two cameras so they would work like eyes. Many of the initial systems using this technology could not get the cameras aligned, so images came out blurred or combined in incoherent ways. As of 2011, many systems have overcome this problem and some are available to consumers.

Before 3D computer vision, there were 3D image processors that could perform the same task of taking images and combining them to form depth. The major problem with this technique is that image processors are expensive, making them largely inaccessible for the consumer market. Cost is not as much of an issue for 3D computer vision, because the process of combining the images is rather simple. This allows the consumer market to enjoy 3D technology without a large price tag.

What Are 3D Desktop Backgrounds?

Three-dimensional (3D) desktop backgrounds are images — made with 3D rendering software or a two-dimensional (2D) graphic design program — that are made to look like they have depth. These 3D desktop backgrounds typically do not create an optical illusion for the viewer the way other 3D media does; rather, they usually are just images that contain an X-, Y- and Z-axis. Depending on the artist, these 3D desktop backgrounds may be realistic or abstract, based on artistic direction and skill. They are just image files, so these backgrounds should work on most operating systems (OSs).

The majority of 3D desktop backgrounds are rendered through 3D image software. To make these images, the artist usually creates a grid and renders the graphics through a series of colors, pre-existing images and layers. These backgrounds also can be made with 2D graphic design software, but this is usually more complex and, thus, rare. Whereas 3D image software is equipped to automatically create 3D images, the artist using 2D image software has to create the illusion of 3D depth through use of shading and other methods.


When people refer to something as being 3D, it usually is a visual illusion made to look like the image is popping out at the viewer; this illusion commonly uses two images and makes the viewer feel like he or she is standing in the image’s surroundings. While some 3D desktop backgrounds may be like this, most are just made with three axes. This gives the image depth, but it usually will not look like the image is coming out to the viewer.

There are many different 3D desktop backgrounds made by artists of various skill levels. Abstract 3D backgrounds typically portray images that are unlikely or unable to occur in reality and rely on various shapes and colors to build the imagery. Realistic 3D backgrounds can be made to look like photos or actual events, and the artist shades the 3D models to make them look like they are real.

While there may be some exceptions, most 3D desktop backgrounds are just regular image files. This means most OSs should have no problem using 3D backgrounds. If an OS does not have a graphical user interface (GUI) or does not have enough memory to support these backgrounds — they typically need more memory than 2D backgrounds — then the computer may be unable to install the backgrounds.

What Is 3D Motion Tracking?

Three-dimensional (3D) motion tracking is the act of capturing motion data from actors and actresses. This is similar to filming a person moving around, but the difference is that, instead of footage that can only be played back, 3D motion tracking records the movements so they can be applied to 3D rendering programs. Performing the capture requires special hardware, such as suits and tiny tracking units, but some systems just need a camera to capture the motion. A subset of motion capturing, called performance capture, deals with extremities and facial features.

The act of 3D motion tracking is similar to filming people moving around, but the difference is in how the information is handled. With filming, the footage can only be watched, while motion capture is a digital model of the motion that can be applied to 3D figures on a computer. This is most often used by the movie industry when creating 3D animated films or when computer-based models require intricate movement. Motion tracking also is used by the military to build virtual exercises and by engineers to control machines.

Special hardware is required to perform 3D motion tracking. In the past, actors and actresses were fitted with suits and small tracking units, and a camera tracked their movement. This hardware is still used frequently, but more advanced systems are able to capture motion data without the need of trackers, known as markerless tracking. A special camera is still needed to translate all movements into digital signals and information.


The practice of 3D motion tracking deals with how the limbs and torso move, but not the finer details of human movement. For finer details, performance capture is used. This type of tracking obtains data from finger and facial movements, so artists controlling the 3D model have intricate data about these movements. Without this information, artists have to create facial expressions and finger movements from scratch, which can lead to awkward expressions or stiff hands and fingers.

Before 3D motion tracking was available, animated film artists in the past used a similar system, called rotoscoping, to track motion. Actors and actresses were filmed performing movements and speaking lines according to the script. Artists would then take the film and draw over each frame individually. This resulted in more realistic animation, because all the movements were based on real people. Most major animation companies, before the advent of the 3D motion tracking, used rotoscoping.

What Is a 3D Engine?

A three-dimensional (3D) engine, often called a game engine, is a system used for virtual computer simulations. Game engines are commonly used in video games, though other non-entertainment applications also exist. A 3D engine has several area of functionality, which work together to create an immersive virtual environment. The rendering component of a game engine calculates the visual appearance of a scene, while a physics component determines how different objects should interact. Some engines also include features such as scripting and artificial intelligence to enhance the feeling of realism.

Game engines streamline several key requirements. During the initial creation of a computer simulation or video game, a 3D engine can be used to simplify the development process. Many simulations and games have the same core features and functionality. A 3D engine allows developers to access common game elements without having to "reinvent the wheel" and build every feature from scratch.

As an example, many popular games are played from a first-person perspective. Even though the story and characters of a new title may be different, the function of this viewpoint is often very similar to existing games. A pre-existing 3D engine can be used to process the visual perspective from this common vantage point. In addition to saving development time, a pre-built game engine also provides players with a consistent and familiar interactive experience.


One common task for a 3D engine is the calculation and rendering of a particular scene. Game engines use mathematical models to predict how rays of light would reflect off of physical objects in the real world. Developers can program in-game objects to emulate certain visual characteristics, and select a material such metal or plastic. When the game is played, the engine will use these variables to simulate the reflection of light, and render a scene that is visually accurate.

If a game includes objects or characters that are movable, the engine may also use math to simulate physics. The 3D engine will often contain a database of physical rules which apply. For instance, a simplified rule might tell the 3D engine that unsupported objects need to fall to simulate gravity. Modern engines contain very sophisticated physics capabilities, which enhance the game experience.

Scripting and artificial intelligence programming can also be included in a game engine. These features allow developers to create characters that seem human. Just as the physics component of an engine allows objects to behave in a realistic way, artificial intelligence can be programmed with a list of character rules. An example of game engine scripting might be a computer character that follows the player through a level, and provides clues or assistance based on the player's actions.

What Is a 3D Accelerometer?

A three-dimensional (3D) accelerometer is an electromechanical device that detects and measures non-gravitational accelerations. These forces can appear as motion, vibration, or orientation of people or equipment. Such forces include static and dynamic accelerations outside the range of normal gravity. This technology appears in many forms and applications, such as those used in video game controllers, smart phones, or pedometers for testing athletic performance. Accelerometers use three-dimensional axes to measure tilt and motion in physical space and provide a wealth of data for movement analysis, digital information processes, or even mechanical safety measures.

A 3D accelerometer might measure voltage variances along three perpendicular axes, by the use of flexing silicon fingers, bubble floats, or other techniques. These horizontal, vertical, and depth (X, Y, and Z) axes allow mathematical analysis of gravity (g) forces, or meters per second per second. One g is equivalent to 9.8 meters/second/second, or 9.8 m/s2. Changes in the piezoelectric voltage of crystals, capacitance between microstructures, piezoresistive effects, and even light all allow the electronic processing of physical accelerations. Some accelerometers require calibration in order to set a resting state to zero, which is actually 1 g in Earth's gravity.


Controlling the tilt and roll of satellites and other dynamic high-technology systems, the accelerometer now also operates in a wide range of common products. The technology is used in tablet computers to orient screens, and also to deactivate hard drives to protect circuitry from falls. It measures performance of automobile braking and suspension systems. The technology also serves in vehicle or personal navigation, as well as in the deployment of automobile airbags.

Accelerometers work in camera image stabilization by controlling shutters to minimize motion blur. They control technology from appliances to missile systems. The devices monitor machine and engine vibrations and the gait of runners and walkers. Applications in smart phones and computer tablets allow for new and creative interactions between virtual and physical realities.

A 3D accelerometer may possess either analog or digital outputs, depending upon the technology it will be embedded into. Another usage factor is the number of spatial dimensions required for analysis; for many applications, two dimensions are sufficient for planar measurements from a fixed mount. Additional aspects include sensitivity and maximum swing, or the range of acceleration forces able to be measured. These depend upon the speeds and impacts involved.

Other computational factors include bandwidth, impedance, and buffering issues, all of which affect accelerometer performance. Cost-effective, lower performance accelerometers are increasingly available and serve consumer markets. Highly accurate devices are found in military, government, and laboratory applications.

What Are 3D Digital Cameras?

Three-Dimensional (3D) digital cameras take a picture with two lenses to create an image that looks three dimensional. Several options are available commercially, and photographers can also create their own systems if commercial ones do not meet their needs. In addition to still photography, 3D video is an option with some products. Working with digital files can be much easier than handling film when it comes to dealing with issues like registration for 3D images, making it accessible to amateur photographers.

In commercial 3D digital cameras, the face of the camera includes two offset lenses. When the photographer presses the shutter, the camera records two images, which can be merged to create a single three-dimensional picture. A toggle may allow people to switch between two and three-dimensional photography for different environments, and it also possible to change between still and video. 3D digital cameras have varying resolutions and quality, depending on model, manufacturer, and intended user populations.

Several types of 3D technology are in use. Some, for example, use colorized layers which must be viewed through special glasses for objects to pop out of the image. Others require people to cross their eyes to see the illusion, or utilize side-by-side pairing and a stereoscopic viewer. 3D digital cameras may enable one or more of these options for the photographer. This can create flexibility to allow photographers to decide on the best choice for a given application.


Photographers may also create their own 3D digital cameras. They pair two cameras side by side, typically using the same model for consistency, in a mount that holds them stable. One advantage to using a mount is the ability to adjust camera position and distance, which can be used to create more depth in the resulting image. Using automated controls, the photographer can snap two simultaneous pictures on the cameras, and process them together in an image editing program to create a three-dimensional image later.

Buyers considering 3D digital cameras may want to try several models to see how they feel, and can ask to see sample images to get an idea of overall quality. Some control systems are more intuitive than others, and the feeling of the camera body can also have an impact; if a camera isn’t comfortable to hold, it won’t be comfortable to use. It can also be important to consider things like resolution, available 3D technologies, and available warranty.

What Is the Difference Between 3D and 2D?

The terms "three-dimensional" (3D or 3-D) and "two-dimensional" (2D or 2-D) are most commonly used in reference to photography and other graphic image technology, such as animation and computer graphics. The difference between 3D and 2D images is that 3D images add the perception of depth. A 2D image, on the other hand, has only height and width. The term "three-dimensional" also is sometimes used to describe a physical item such as a sculpture or mobile, which could be described as three-dimensional art, in comparison with a two-dimensional painting.

Three-dimensional imagery cannot be created without duplicating the effect of two eyes working in tandem, which allows three-dimensional perceptive effects such as depth perception. Early 3D technology imitated this process with dual-camera or dual-lens setups. Modern computer technology can easily create realistic effects in both 3D and 2D.

Photography records images for reproduction on flat, two-dimensional surfaces, such as paper prints or display screens. This has the effect of flattening the image, reducing or eliminating the effect of depth. Natural vision produces this effect because the eyes are set slightly apart, allowing the brain to process two different views of the same image. During the late 19th century, photographers attempted to rectify this problem with dual still and motion cameras that were designed to work in tandem. Viewing these “stereoscopic” images through special viewers simulated the effect of seeing a three-dimensional image.


The terms 3D and 2D first came into popular use because of the film industry. During the 1950s, Hollywood filmmakers experimented with 3D movies as a marketing gimmick. These movies were filmed with a variation on the stereoscopic dual-camera setups. They were expensive to produce and required viewers to wear special glasses to experience the 3D effect. Only a few of these movies became lasting classics, most in the horror/suspense genre, such as House of Wax, Creature from the Black Lagoon and Alfred Hitchcock’s Dial M for Murder.

A second wave of 3D films in the 1980s had similar results. The earliest video games, meanwhile, also had 2D graphics, but in the 1980s and 1990s, rapid advances in computer processing and memory made more realistic images possible. By the 21st century, computer-generated imagery (CGI) could create 3D and 2D effects for big and small screens alike. In 2009, James Cameron’s film Avatar pioneered a new wave of cinematic 3D by combining cutting-edge CGI and digital filmmaking technology. Soon, many of Hollywood’s big-budget effects films were following suit.

In real life, there is another crucial difference between 3D and 2D vision. Three-dimensional vision contributes to depth perception, or the ability to estimate an object’s distance. This fact has been humorously pointed out on the science fiction television series Futurama because one of the show’s main characters, Leela, has only one eye. Despite being the pilot of an interstellar space ship, Leela often complains that she has no depth perception. Ironically, Andre de Toth, the director of the famous 3D film House of Wax, also had only one eye, and he could not see in 3D.