Tuesday, June 8, 2010

Depth Perception


            As our eyes gives us images we have not really paid attention to the reason why certain objects looks different from different angles. This is called "Depth perception" which is the ability to see the world in three dimensions. Although the ability may seem simple, depth perception is remarkable when you think about that each image is projected on each retina are two-dimensional. From these singledimension images, we construct a  three-dimensional world. To perceive depth we depend on our two main sources of information, binocular disparity and monocular cues.
          Since our eyes are spaced away from each other we have two different images. our left and our right images are different because each eye looks at the image at a different angle.This is called binocular disparity. Our brain works with our left and right images combining both images together making the image three demensional. Our brain also combines both images allowing us to see close and far away. We can see binocular disparity working when we hold objects really close to use the space between our eyes allow us to see the object at two different angle letting the brain combine the image and making the object three dimensional. The surounding object becomes blurry and all we are able to see is the object.
         If one of our eyes is shut we can see the objects still and make it three dimensional. we are able to tell the size, shape, texture, and distance. This process is called monocular cues. one of the main focus of monocular cues is when we have an object blocking our view, we can see the blocking with one eye, right or left, but when we open our second eye we can see beyond the object that is blocking making it seem the object is far away. We percieve the size of object depending of the familiarity of the object and we can assume the height. We are then percieve when the familiar object is paired up with a similar object making our eyes percieve the two hieghts are the same but we must measure the distance between them because the distance between the two objects make us think they are the same height. This is called size and height cues. Another cue that makes us percive the image we are seeing is motion parallax. This cue makes us think the object is moving because of its texture and its postion. The farther or closer we get the object seems to be moving with us whether close or farther away.
              Next time we are  trying to see pass the head of the person in front of us let us think why we are still able to see some things passed them when one side of us we can't, its because of our cues and disparity we have.


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