Re: Rotated square in space

Just forgot to mention

sci.image.processing

as the newgroup also very well
suited for such kind of question.

Claudio
"Claudio Grondi" <claudio.grondi@xxxxxxxxxx> schrieb im Newsbeitrag
news:3gjl1tFci2hnU1@xxxxxxxxxxxxxxxxx
> > Any other suggestions or clarifications?
>
> I have assumed, that you speak about parallel
> projection, but you don't, so it is not known
> what I assumed as given, i.e. the x, y coordinates
> of the corner points :(
>
> So if you want to do it for a picture created by
> a camera, I _suppose_ you have to know the
> appropriate parameter of the lens system, the
> current setting of camera focusing and the
> distance of two corners of the square from the
> camera.
> I _suppose_, that if you only know, that the
> object is a square it is not enough to calculate
> the transformation matrix.
>
> I think, that if you ask this question in
> comp.graphics.algorithms
> you will get better and more qualified
> response.
>
> By the way:
> distance in 3D between two points p1 p2 is:
> sqrt( (x2-x1)^2 + (y2-y1)^2 + (z2-z1)^2 )
> where
> sqrt() means square root (exponent value of 0.5)
>
> Claudio
>
> "Luiz Borges" <luiz_borges@xxxxxxx> schrieb im Newsbeitrag
> news:1118072652.226562.37970@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > Thanks all for your answers...
> > Actually if I find ANY square in the 3d space the fits the projection,
> > it will work... it doesn't matter if there are infinetely squares...
> > today I was think on something alike Claudio said, but working with
> > angles formed between the edges... but i guess that working with
> > distances might work better.
> >
> > What I don't see is how to calculate that, my last geometry lesson was
> > 5 years ago lol :)
> >
> > Explaining a bit, what I want to do is that: a program that takes a
> > picture, the user marks the four corners of an square object in the
> > picture, and then I have to mark some specifics points inside that
> > object... if I have transformation matrix for the object in 3d space, I
> > can plot those points...
> >
> > Any other suggestions or clarifications?
> >
> > Luiz Borges
> >
>
>


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Relevant Pages

  • Re: Rotated square in space
    ... > Any other suggestions or clarifications? ... a camera, I _suppose_ you have to know the ... object is a square it is not enough to calculate ... > Actually if I find ANY square in the 3d space the fits the projection, ...
    (sci.math)
  • Re: Rotated square in space
    ... which is the picture of the square. ... exact equations for getting the x,y ... > Replying to Claudio, I didn't give those last details because I haven't ... > projection plane would intersect the piramid... ...
    (sci.math)