The Visual Perception System
Organisation- Finding Form :
Organisation- Finding Form or meaning by using depth cues and gestalt principles, : Once the visual information reaches the visual cortex, it is organised to make the information more meaningful for us. We organize information by using certain visual principals such as depth cues, the Gestalt principles and depth cues. Once the information is reassembled, the image then travels toward the temporal lobe of the brain to identify the image and to the parietal lobe to know the placement of the object in space.
The Visual Perception System
The visual perception system is made up of a number of different components, such as the: eyes sensory receptors nerve pathways visual cortex. It is convenient to think of the visual perception system as a two-stage process of visual sensation and visual perception.
Visual Perception
Visual perception is the process that allows us to give meaning to sensory information, leading to our own personal interpretation of that information. Unlike visual sensation which is purely physical, visual perception is both physical and psychological. Visual perception is an active process, where our brain actively processes information that we see, hear smell and so on. Visual perception allows us to adapt to our external environment and live our lives the way we do.
The EYE
Aqueous Humor A clear fluid that helps the cornea keep its rounded shape. Vitreous Humor The thick, clear jelly that helps give the eyeball its shape. Blind Spot The place where all nerves from the retina join to form the optic nerve. Each eye has a blind spot where there are no light-sensitive cells. Cornea The cornea is the first point of contact for light reflected or transmitted from objects in the world. The cornea is a transparent, convex-shaped covering which protects the eye and helps focus light onto the retina in the back of the eye. Light bends as it passes through the cornea. The cornea begins bending light to make an image; the lens finishes the job. Iris A muscle that controls how much light enters the eye. It is suspended between the cornea and the lens. A cow's iris is brown. Human irises come in many colors, including brown, blue, green, and gray Lens A clear, flexible, convex structure that makes an image on the eye's retina. The lens is flexible so that it can change shape, focusing on objects that are close up and objects that are far away. (adjusts its shape depending on the distance of objects being viewed) Plays a major role I focusing light into the retina. Optic Nerve The bundle of nerve fibers that carry information from the retina to the brain. Retina The layer of light-sensitive cells at the back of the eye. The retina receives and absorbs light and also detects images focused by the cornea and the lens. The retina is connected to the brain by the optic nerve. Pupil The pupil is the dark circle in the center of your iris. It's a hole that lets light into the inner eye. In places where there is limited light the pupil expands to let in more light.
Reception Taking the light in
Reception -Taking the light in: The process by which the eye receives incoming information from the external environment. This visual information is focused on the retina of the eye where the visual image is captured. Inside the retina there are many specialized neurons called photoreceptors. There are two types of photoreceptors called Rod and Cones Rods They are responsible for peripheral vision. (seeing things out of the corner of yor eye) Respond to very low levels of light and are primary responsible for night vision They can only register black and white images. Cones Respond to high levels of light and primarily responsible for our vision in well lit conditions. Can detect fine detail Responsible for colour vision
processes of the Visual Perception System
The different interactive and interdependent processes of the Visual Perception System are- Reception Transduction Transmission Organisation Interpretation
Transduction
Transduction -Converting light energy to electroochemical; energy for nuraal impulses When light reaches the photoceptors it comes in a from that cannot be processed by the brain. The photoreceptors then convert the light energy into electrochemical energy required for neural impulses. This is conversion called transduction, which allows the the energy to travel as a neural impulse along the optic nerve. In this process electromagnetic energy (light) is converted into electrical impulses (signals)
Transformation- Finding Meaning:
Transformation- Finding Meaning: Finally the visual image is given meaning, so that we can understand what we are looking at. Past experience, motives, values and context help us understand the visual information that has been presented. The temporal lobes help to identify the information from already stored memory and parietal lobe helps to know where the object is placed in our visual field.
Transmission -From eye to brain:
Transmission -From eye to brain through nerve impulses: This occurs when visual information is sent to the brain in the form of electrical impulses. The optic nerve carries the information to the visual cortex located in the back of the brain. The visual cortex is and area of the brain that specializes in receiving visual information.
Visual Sensation
Visual sensation is the process which enables the sensory receptors in our eyes (located on the retina) to receive light energy from the environment (electromagnetic energy) and convert it into a form that the brain can interpret (electrochemical energy). Visual sensation is a physical process, which means it can be explained just by looking at the workings of the eye, neural pathways and parts of the brain.