Visual Cues and Constancies

Visual cues are critical elements for depth perception. They provide information about depth and distance in a 3D world.
Visual cues can be either monocular cues (perceived even with one eye closed) or binocular cues (perceived using both eyes).
Key types of monocular cues include texture gradient, interposition, relative size, and linear perspective.
Texture gradient refers to details of the texture that can be seen clearly when the object is closer but gets denser as the object is farther.
Interposition occurs when an object blocks the view of other objects, indicating that the blocking object is closer.
Relative size is when objects that are further away appear smaller than those that are closer.
Linear perspective refers to the parallel lines converging as they move further away, giving the impression of depth and distance.
Key types of binocular cues include retinal disparity and convergence.
Retinal disparity refers to the slight difference between the views of the left and right eyes due to their slightly different location on the face. This creates a sense of depth.
Convergence is the degree to which the eyes turn inwards to focus on an object. For close objects, eyes converge more.
Visual constancies are perceptions that do not change even though our viewpoint or the lighting conditions might.
Size constancy is the ability to perceive an object as the same size despite the changes in the shape of its retinal image.
Shape constancy is the ability to perceive an object as having the same shape despite it being viewed from different angles.
Colour constancy refers to seeing familiar objects as having consistent colour, regardless of changing light conditions.
Brightness constancy means the perception of an object being of the same brightness regardless of the light in the environment changing.

Remember, understanding of visual cues and constancies is crucial in understanding how we perceive our world and interact within it.