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Thread: PARALLAX [URGENTLY NEEDED!!]

  1. #1 PARALLAX [URGENTLY NEEDED!!] 
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    Hello, this is Chetan here. I am having problem with understanding what is Parallax, can somebody describe the whole thing? I want to know it's applications, method and other related things.

    I need this information urgently, so pleas help me with this. I would appreciate your help.

    -Thanks
    Chetan Bhasin


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    Parallax is the effect of more distant objects appearing to move slower than closer objects. This has been used to measure the distance of stars from Earth.

    You could attribute this effect to the fact that objects closer to you will exhibit a greater angle per distance moved than farther away objects due to the geometry of space.

    If you were at the bottom middle of an arm of a triangle, with one object at the top of the triangle and another slightly in front of you near the bottom, and you moved some distance x either to the left or right, the angle drawn from you to the nearer object will be smaller than to the one farther away at the top of the triangle. What this means, is that you 'rotated' around the closer object to a greater extent than the farther away object, so this must mean to you that you traveled a greater distance away (as far as you can tell) from the closer object than the further away one, even though your displacement on the X axis is the same from both objects.

    A part of this also has to do with the circular emission pattern of light and how that light recombines in your eyes. Light that comes from an object farther away will make the object appear smaller because only the light with a small angle of emission can hit your eyes from a distance, since those are the only beams that travel straight enough to physically hit your position. This smaller angle of incidence to your eyes lenses results in a smaller point of light on your retina, and therefore the appearance of a smaller object. This is what gives us depth perception. Study Snells Law for an explanation on that.


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    Suppose you are looking through a telescope that has crosshairs. If you move your eye slightly to the right or left, while keeping the telescope in a fixed position, the crosshair will appear to move relative to the object you are sighting. This is called parallax error. A telescope can be made or adjusted to eliminate parallax error at a certain range, but then it will have the error at longer or shorter ranges.
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  5. #4  
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    Quote Originally Posted by Harold14370
    Suppose you are looking through a telescope that has crosshairs. If you move your eye slightly to the right or left, while keeping the telescope in a fixed position, the crosshair will appear to move relative to the object you are sighting. This is called parallax error. A telescope can be made or adjusted to eliminate parallax error at a certain range, but then it will have the error at longer or shorter ranges.
    Harold is correct.

    Cold Fusion is, as usual, as screwed up as cold fusion.
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    Hey....you guys are just misinterpreting me. I suppose its a good thing though....

    May I ask what portion you thought was incorrect?
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
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  7. #6  
    Forum Professor jrmonroe's Avatar
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    parallax
    n.
    1. the apparent change in the position of an object resulting from the change in the direction or position from which it is viewed.

    So ... Stretch out your arm in front of you with your thumb sticking up. Close one eye, and notice the distant objects that the thumb obscures. Close that eye and open the other, and notice the distant objects that the thumb obscures. Parallax is the difference in your thumb's apparent "position" (based on what's behind it [and sometimes on what's in front of it]) due to being viewed from different points of view (your eyes).

    PS to Cold Fusion You seemed to give advanced/ancillary information when an introductory kind of explanation seemed better suited.
    Grief is the price we pay for love. (CM Parkes) Our postillion has been struck by lightning. (Unknown) War is always the choice of the chosen who will not have to fight. (Bono) The years tell much what the days never knew. (RW Emerson) Reality is not always probable, or likely. (JL Borges)
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  8. #7  
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    Quote Originally Posted by Cold Fusion
    Hey....you guys are just misinterpreting me. I suppose its a good thing though....

    May I ask what portion you thought was incorrect?
    For starts, parallax has nothing whatever to do with motion, for starts.

    You really do need to learn some basic physics and mathematics. Your ongoing demonstrations of profound misunderstanding of both are awe inspiring.
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    I was referencing 'movement' in the difference in position that you view between objects.

    "This animation is an example of parallax. As the viewpoint moves side to side, the objects in the distance appear to move more slowly than the objects close to the camera."

    http://en.wikipedia.org/wiki/Parallax

    You just do not like my way of wording things. If my understanding was that bad, then how am I making a living off of it right now?
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
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  10. #9  
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    Quote Originally Posted by Cold Fusion

    You just do not like my way of wording things. If my understanding was that bad, then how am I making a living off of it right now?
    Your understanding has been demonstrated, many times, to be that bad.

    As to your question, there are a lot of gullible fools out there in the world and I have seen them hire some completely incompetent, counter-productive, consultants. Your customers are surely of that ilk.
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  11. #10  
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    Quote Originally Posted by Cold Fusion
    Parallax is the effect of more distant objects appearing to move slower than closer objects. This has been used to measure the distance of stars from Earth.

    .

    That is exactly what I was going to say.

    But that is not "parallax" it is "parallax effect".

    All video game programmers know "parallax effect". "Parallax" is more obscure
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  12. #11  
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    Quote Originally Posted by jartsa
    Quote Originally Posted by Cold Fusion
    Parallax is the effect of more distant objects appearing to move slower than closer objects. This has been used to measure the distance of stars from Earth.

    .

    That is exactly what I was going to say.

    But that is not "parallax" it is "parallax effect".

    All video game programmers know "parallax effect". "Parallax" is more obscure
    It would be equally wrong if you said it.
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  13. #12  
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    Angular velocity and angular diameter are related to parallax.

    Parallax scrolling is used in some video games.
    Grief is the price we pay for love. (CM Parkes) Our postillion has been struck by lightning. (Unknown) War is always the choice of the chosen who will not have to fight. (Bono) The years tell much what the days never knew. (RW Emerson) Reality is not always probable, or likely. (JL Borges)
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  14. #13  
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    Quote Originally Posted by DrRocket
    It would be equally wrong if you said it.
    It would be equally wrong in a scientific context; it appears it may not be wrong in a gaming context. Shame that this is a science forum and cold fusion could have been right for once.
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  15. #14  
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    Quote Originally Posted by Ophiolite
    Quote Originally Posted by DrRocket
    It would be equally wrong if you said it.
    It would be equally wrong in a scientific context; it appears it may not be wrong in a gaming context. Shame that this is a science forum and cold fusion could have been right for once.
    But it is a science forum, and we still await the first instance in which he is right.

    I, for one, am not going to hold my breath.
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