By Dwayne Godwin and Jorge Cham
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| July 2, 2011 | 7
By Dwayne Godwin and Jorge Cham
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7 Comments
Add CommentWait a minute; the more disparity in the images, the further away it is? I don't think so!
Reply | Report Abuse | Link to thisThey got that one completely backwards. Common sense tells us as an object increases its distance from another, the ability to perceive small differences decreases, not increases. Close objects "jump" in your eyes when you blink them; distant ones do not. The effect of distance on differences is the opposite of what they said it was.
Yes, I'd have to agree with promytius. The closer the object the more obliquely each eye will perceive that object relative to each other. Conversely, the farther the object, the closer the bisecting angle becomes; and, therefore, the more congruous the images are to each eye's receptive field.
Reply | Report Abuse | Link to thisCan someone with more expertise in the field please clear this up?
Thanks!
Actually, I believe the writer is correct. The dialogue contains no reference to distance. The only parameters mentioned are disparity and depth. The author, I think, is assuming that we are all aware that depth is most evdent in closer objects.
Reply | Report Abuse | Link to thisThis strip is like explaining sawing a woman in half with:
Reply | Report Abuse | Link to thisa) The woman enters the box.
b) The magician closes the box.
c) The magician gives the impression of sawing the woman in half.
Unfortunately most of the magic is hidden behind "DEPTH YOUR BRAIN ASSIGNS TO THAT PART OF THE IMAGE".
No one has the remotes idea how or why the brain "GIVE YOU THE FEELING". That is the problem of duality or what some philosophers refer to as Qualia.
As a person blind in my right eye, a prosthesis,it always amazes me when I perceive something with depth when clearly I do not have the ability. There are tricks I employ to determine distance, a remaining in motion as I move slightly to one side to provide me offset spatial information. Sometimes I will use polarized sun-glasses removing them and putting them back on, or the ability to interpret converging lines, while another method employs the interpretation of shadows...I think best, long before losing my sight, I trained to be a mechanical draftsmen so could mentally interpret depth. I could see 3D in my minds eye.
Reply | Report Abuse | Link to thisThere is this, and fascinates me beyond measure, how some artist in their paintings their images appear as if in 3D to me...things in their painting jump out to me - versus other artist who works remain static 2D flat. Some artist have this ability to interpret depth and how it is done is what intrigues me for I am without explanation...worst tricks are played as sometimes things appear to jump out at me but under closer examination I find it is a 2D illusion. It is in the avoidance of something that is not there which is the hardest to deal with...especially when your mind tells you one thing and your eye tells you another.
What is worst when people you know delight in playing tricks, hurtful tricks, such as holding a bill so I can see its face and handing it to me...I can reach out and take it every time...then they are the game players that turn the bill so I only see a line in space that I can reach for over and over and never once even come close...the bill holder amused at my expense.
In the end, there are several methodologies I, as an individual imprisoned in a two dimensional world, use to determine dimensionality and distance and I can easily prove my effective ability to determine distance - not to long ago in front of about 40 people at a local shooting range and at a measured 30 meters, in 1.7 seconds [first round to last round], I put 17 rounds [180 grain hollow points] into a target eight rounds touching at bulls eye and a total of 13 rounds that would cover the measure of a man's heart. 16 out of 17 within five inches and one outlier that would have been a belly shot. And this with 'hot' reloads made for a highly combat modified officer's model .45 cal with an Exata-Ace Barrel and that was Magna-Ported and I carried on my CCW in California. When it is dark this configuration provides me a 'V' image from vented exhaust gases, and quick target acquisition by retinal image retention.
Don't forget in normal vision, one eye shuts down to interpretation and the mind only uses the vision of one eye at times. So many times in the 3D environment you are only seeing in 2D. The minds has interpreted the 3D environment then goes 2D switching back to 3D when ever needed. Every competitive shooter on the target range knows this and they will actively determine which eye is their dominate eye. Otherwise the target shooter will see two sight pictures, two sets of sights, and two targets all at different angles. Some women have told me they see this effect, they usually close one eye...other and usually men, the dominate eye takes over.
Reply | Report Abuse | Link to thisYes, and relative disparity depends on whether the eyes are in a vergence position (converging on a target) or in a relaxed position (like the case in a movie theater). If your eyes are focused on a spot on the wall and your finger is moved toward your nose, then the disparity of the two images of the finger on the retinae diverge more. However, if you perform a vergence movement of the eyes to keep the image of the finger fused you'll notice that the spot on the wall diverges. Basically there is divergence on either side of the plane of fixation and convergence.
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