Question about the line

[PROBERT1968]

Hello

I have a question about the line I circled it..

Why does it do that and what does it mean ?  What do you call that ?

[James]

I believe that's an epipolar line.

See figure 3 from here, attached below.

The 3D point X is only placed in one aligned image (the left hand one) as x, so all that you can say about it in the right hand image is that it must fall on epipolar line l'.

(All epipolar lines in the right hand image originate at/intersect the epipole e', which is the point at which the point from which the left hand image was taken appears in the right hand image, although in practice this is not necessarily within the right hand image's field of view.)

So all it means in your example is that 'point 6' has only been placed in a single aligned image, and in the aligned image you are looking at it should appear somewhere along the indicated dashed line. Once you place it in that image there will be enough information to locate it as a 3D point in space, and so subsequent aligned images will show it in that location, rather than as a line of possible locations.

[PROBERT1968]

Thank you, James .  Now I know what that line means and the name of it.  It makes sense.  Yes I was able to fix it.  I just need to know why it is there and show up.....