s+p exam 4 pt 5

oculomotor cues:

combies accommodation, convergence, and gaze elevation

• Accommodation: gets stronger when things are closer to us, and the feeling we get from accommodation and vergence can be used as a depth cue. But for accomodation and convergence, it is only good for 6ft in front of you, beyond that it doesn’t feel that different 

• Gaze elevation: if you’re sitting in a chair in the dark, where are your eyes looking vertically (we’re looking below our physical eye height) → Gretzmacher wanted to know if gaze elevation could be used as a measure for distance perception– they had people look through prisms base up or base down– this would shift the world up or down (if you’re looking at something in the world while wearing these prisms, you need to change your posture) they had people look at something w a prism, then shit their eyes and walk towards it, we saw that in the control condition, they were a meter short, but for based down the whole world moved up, so they walked significantly further, and for base up (where everything is shifted down) they walked significantly less→ they found that gaze elevation 9our eye posture vertically) can act as a cue to distance

what are the 9 monocular depth cues that are pictoral?

• Interposition: if one thing blocks another, it must be in front of it

• Relative size: we will make visual comparisons of size to help us determine depth (we’re going to make the comparisons of all the telephone ples, they get smaller and smaller in the distance, we’re making these relative comparisons to help us w distance perception)

• Familiar size: (contrasts relative size w this): if you know the size of something, it’s going to help you determine how far away you are fromm if (you know how big your friend is, so walking toward her you know how close you’re getting to her) (as soon as we have something familiar (the thumb w the mug) we can see how big it is)

• Linear perspective: parallel lines seem to converge in the distance (the drawing: the lines on the tile seem to converge in the distance) (road lines- a lot of lines all seem to be converging)

• Texture gradient: we see more details of things that are closer to us (we see the individual bricks up close, but as they go further away, the bricks lose their distinction OR individual grains of sand up close but then looking a foot away and then all we see is beach/sand)

• Height in plane– things closer to the horizon will be seen further away (ex- laying on the beach, theres a seagull overhead and one over the water– the one over the water will be seen as further away) (in the pic, the clouds seem closer than the mountain in the distance)

• Ariel perspective: things in the distance look hazy or blueish 

• Shading: the use of shading (espcecially in drawings or paintings can give us depth or 3d) (can see the flat parts and mountains or the 3d ness of the guys face)

• Shadows: two diff kinds of shaddows: cast shadow (unattached– the shaddows are not attached to the things– the gulls on the beach– these can be used for distance (if we can see the outline of the bird on the ground, it must not be that far off the ground). The attached shadow will giev more shape, which gives more 3dness, which is a part of distance or depth

what is the one monocular depth cue that is not pictoral and what is it?

• Motion parallax: not a pictorial cue (the rest were beecuse they can be captured in a photograph or painting, but this one cannot because theres movement). Things at different distances will move in different directions. As you get closer and closer to the fixation point, things don’t seem to be moving as fast– rotation around the fixation point. This can be explained through physiological optics (basically whats happening on the retina): in position 1, we have one eye and the square, x, and circle are all lined up→ move from position one to position 2 and now only the x is on the fovea (1 and 2 are the same eye)-- we sdee the circle and square moving in diff directions because they’re moving in diff directions on the retina. 

steropsis:

• a type of binocular depth cue

• Steropsis: the perceptual experience of depth (our ability to see depth) as a byproduct o(comes along for the ride) of the disparity of the images in each of the eyes (different images in each of the eys) → our eyes are separated by some distance, meaning we’re going to get a bit of a different view from each of the eyes (think about taking a picture from a slightly different angle). (closing one eye and having one finger block the other and then switching eyes and being able to see both fingers again).