Viewing In Three-dimensions
Stereoscopic vision refers to the ability of human eyes to see the surroundings through a three-dimensional view with two eyes. The eyes are required to be intact and synchronized in their movements to be able to view the same object differently. This movement enables humans to interpret distance and hence evolve their ability to have a true sense of their perception of depth. Each eye in humans and animals sees images slightly differently which is known as retinal disparity. Thus enabling the brain to process images without any physical movement. It is brought about by complementing matches of different images obtained and then calculating the difference i.e, the retinal disparity of the two images. The disparity hence obtained varies by a very small margin but the final outcome is the most accurate version of the image that is attainable of the ambient depth perception.
Stereoscopic Vision In Humans
Each eye captures its own images and sends two versions for the brain to process it. Human eyes have the most evolved and advanced sense of vision which is brought about by the exact synchronization of the brain and the eyes as they possess the frontal vision, foveas, primates and felines and so on. Since our eyes are around 2 inches apart, two images are generated and sent to the brain for their processing, the disparity on the retina creates a combined overall image which also provides a sense of distance of an object. Our brain uses this spatial information by storing and reusing to save computing time. Stereopsis is the precise depth information given by the eyes.
See also: Structure Of Eye
Stereoscopic Vision In Animals
Interpretation of depth information by eyes from images acquired simultaneously through different spatial locus results in a binocular vision in animals. Some animals have their eyes positioned in two different directions which helps them catch their prey. This way they are provided with the largest possible field of view. Some aerial animals have a 360-degree field of view, while some other animals have their eyes positioned in front of their head, forward facing eyes. Animals with forward-facing eyes can fix their eyes on a single object or independently move their eyes such as chameleons.
How Is Stereoscopic Vision Beneficial?
- Stereoscopic vision helps humans manage and handle small objects manually
- Provides depth perception
- Enables animals to traverse through dense forests
- Provides an ability to assess threats and react quickly
- Used in industries where a high degree of accuracy is essential (medicine, research, aviation)
- It creates a depth of field where an object is dominant, and the ambience is not sharp.
- Enables selective vision
Other Methods
Human eyes do not use the mechanism of stereoscopic vision always to interpret distances, they use the focal length to judge distances which require exact focusing by the eyes. This, however, is not as accurate as stereoscopic vision, hence it is used in association with the stereoscopic vision to yield accurate results.
Stereograms
A stereogram is a computer-generated image of an object delivering a three-dimensional view created from a 2D image. It is brought about by two methods:
- Cross-eye viewing – Viewer focuses his eyes in front of the image and requires to cross his eyes in order to view.
- Parallel viewing – Viewer made to view parallelly, where eyes focus on somewhere behind the eye by taking a relative parallel angle.
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