Visual cues and constancies

• Visual cues are features of our environment that give us information about movement, distance and where things stand in relation to one another. This allows us to perceive objects we see as a constant. Even though we see them from various angles and different distances. Since one particular type of visual cue is a depth cue, which helps us see how far things are away at any 1 time.
• Some depth queues allow a person to judge debt and distance using one eye.These are called monocular depth queues.
• Some depth cues allow a person to judge depth and distance using 2 eyes. These are called binocular depth cues.
• Retinal disparity is a binocular depth cue and happens because our eyes are about 6 cm apart. This means each eye gets a slightly different view of the world. Disparity means different and retina is the screen of back of the each eye and receives all visual input. The amount of difference there is in the image gives the brain important information about distance. The closer the object is, the bigger the difference between the 2 images is. The further away the object is the less of a difference there is.
• Convergence is a binocular depth cue. If 2 things converge, they become closer together. When our eyes follow an object that is coming towards us, our eyes to come together. The muscles round our eyes have to work harder when viewing objects up close. When looking an object that is far away, the muscles are relaxed as are always looking straight ahead. This muscle information provides our brain information about depth and distance of objects within our environment.
• Height in plane is a monocular depth cue. Objects are higher up in the visual field appear further away and this is height in plane. Height in plane acts as a depth cue.
• Relative size is a monocular depth cue. When objects appear smaller in the visual field, the known objects of similar size- i.e. the relative sizes are different- they are perceived as being further away.
• A occolusion is a monocular depth cue. Some objects that are obscured by other objects or are further away. This is called a occlusion.
• Linear perspective is a monocular depth cue. Lines that are parallel appear to get closer together and come to a point in the distance.