Introduction
One of the most common causes of fatal helicopter accidents is Controlled Flight Into Terrain (CFIT) at night. (FlightWeb). The major contributor to such accidents is the pilot's level of situational awareness, or rather not being able to see where they are going, or what might be in the way of unobstructed flight. As helicopters are routinely used in low-altitude missions they are frequently required to fly in close proximity to trees, power lines, telephone poles, etc. As such, it is vitally important for the pilot to be able to see and avoid these hazards to navigation. During daylight hours, these hazards pose a minimal risk to flight. However, as the sun sets and the amount of visible light wanes, these same hazards become life threatening.
The reliance on night vision technology has become invaluable in assisting aviators in flying at night. By magnifying the ambient light, Night Vision Goggles (NVG's) and devices reduce the problems associated with unaided vision in the dark.
The Human Eye and Night Vision Goggles
Vision is a physical sense that uses light to provide information to the brain in order to make conclusions about the surroundings. The human eye is an intricate organ that works best when there is an adequate supply of light. Our eyes have been often compared to cameras in that a camera filters light through the lens, controls the intensity with an aperture and focuses the image onto a film. Light coming into an eye is filtered through the cornea, the iris regulates how much light comes through, and then it is focused by the lens onto the retina.
During the day, we are able to detect color, depth perception, distance and visual acuity. At night, all of those senses are greatly diminished. Visual clarity can be reduced to 20/200 or greater at night. The sensitivity of the retina (where images are focused) is greatly hindered when the light levels drop.
On a clear night (with a full moon and no clouds), the unaided eye can make out details of the surrounding terrain from approximately 100 feet in the air. With NVG's, everything on the ground can be clearly seen from an altitude of 1,500 feet above ground, and up.
In using the same camera analogy in describing the eyes, we can use that of a video camera to describe how Night Vision Goggles (NVG's) operate.
Laila confirms that her friends have ordered pizza using her visual system. Through the sensation of light, sensory information is processed and Laila is then able to see the pizza. The pupil absorbs light, by allowing light to enter the eye, and light will then be transferred to the lens. The lens is responsible for refracting light and focusing the light inside of the eye, also known as the retina. The second cranial nerve, or optic nerve, is responsible for carrying the visual signal from the eye to the optic chiasm. The optic nerve, or second cranial nerve, is located in the back of the eye. This cranial nerve transfers visual information to visual centers in the brain through many electric impulses. The optic chiasm has temporal fibers that travel ipsilaterally as nasal fibers transmit information contralaterally, to the opposite side of the associated visual field. The visual cortex can then process sensory information from the opposite eye. Laila’s blind spot is where the optic nerve begins and there are no rod or cone cells in the optic nerve. The brain has to try to compensate for the lack of photosensitive
Blindsight is often understood as supporting certain claims concerning the function and the status of the phenomenal qualities of visual perceptions. In this talk I am going to present a short argument to show that blindsight could not be understood as evidence for these claims. The reason is that blindsight cannot be adequately described as a special case of seeing. Consequently, it is not possible to draw inferences from it concerning the role of the phenomenal qualities for seeing.
Peripheral vision is used amongst every species ranging from a deep-sea marine animal to a bird flying hundreds of feet above the ground. However, each species’ vision differs to some degree and also differentiates within the species itself. This can be due to various types of eye conditions.
The eye is an important sensory organ for vision which houses a sensitive optical apparatus in a relatively isolated tissue compartment. Eye is essentially made of three layers: (1) sclera, (2) uveal tract, and (3) retina with each of these layers performing intricate duties which ensure proper functioning of the eye.
Sight helps us navigate the world around us more than any of our other senses. In a fraction of a second, our eyes work with our brains to tell us the size, shape, and texture of an object. They also tell us how close it is and if it’s still or moving. The structures of our eyes are incredibly complex, despite how small they are compared to the rest of our organs. The human eyes are extremely delicate. The visible part of the eye is protected by the eyelids and eyelashes, which keep out dirt, dust, and harmful bright light.
the eyes had densely packed lenses and may have served merely as a light sensitive
The retina contains rods and cones which detect the intensity and frequency of incoming light and, in turn, send nerve impulses to the brain.
5) Pattern of neuronal activity associated with conscious and unconscious processing of visual signals, Sahraie, et al.
Eyes are the ‘organ of sight or vision; the visual sense; the sense of seeing’ (Biology-Online). The eye is an organ that detects light and sends signals along the optic nerve to the brain. The eye allows for light recognition and the ability to differentiate between colors, and light and dark. The eye is approximately 2.54 cm wide, 2.54 cm deep and 2.2 cm tall. The human eye has around 200-degree viewing angle and can see and detect more than 10 million colors and shades. This essay is going to look at ways of seeing. The possible problems with eyesight, and eyes of various kinds. It is one of the most rare problems today that is affecting people, all over the world. Around the world an estimate of 4 in 10 people have perfect vision/sight (BBC). The population of the world right now
Now for our eyes we use them for vision, their like our own personal camera’s,
Unfortunately, humans become colorblind at night because their eyes switch from normal daytime vision to a color-insensitive rod system. Unlike humans, a lot of other animals have the ability to see in the dark. This nocturnal ability is a major subject of research because scientists want to know what causes it, what methodology lies behind it, and what limitations there are.
One sub-system under the sensory system is the visual system; the main sense organs of this are the eyes. The eye is the sensory organ that allows us to detect light from external stimuli. When a light ray is detected, the eye converts these rays into electrical signals that can be sent to the brain in order to process the information and giv...
How would pilots ever get around so easily without the help of navigation aides? Navigational aides have been around for almost as long as aircraft have been flying in the skies above us. The first navigation system was composted of just a high intensity-flashing beacon. These beacons were placed on the flight routes that were popularly flown in the mid 1920’s. With more time more of these technologies that help us navigate the world will be even simpler than today. This paper will explain how some navigational aides work and how some of them came into existence.
Have you ever wondered why the sky is blue. Often times I find myself looking up on a clear day, pondering over that question? Why isn’t it green, or red or pink for even that matter. Every day, the human eye blinks more than 23,00 times. The human eye is a complicated organ that performs one of the most important tasks for our body. There are many questions about the eye however. What function do they perform? What happens if we don’t take care of them? How exactly do they work together to help us form images? Exactly how far can they human eye see?
The Eye is the organ of sight. Eyes enable people to perform daily tasks and to learn about the world that surrounds them. Sight, or vision, is a rapidly occurring process that involves continuous interaction between the eye, the nervous system, and the brain. When someone looks at an object, what he/she is really seeing is the light that the object reflects, or gives off.