Creating 3d coordinates from stereoscopic images

In summary, you are trying to find the coordinates of a point object in an image, using the camera's depth and 2D coordinates. You need to find the focal point, disparity, and distance between the cameras to convert the point coordinates.
  • #1
steven77723
4
0
Hi, I'm working on a project that would take a 3d image using stereocopic camera and would record the depth and the 2d (x1,y1) , (x2,y2) coordinates of a single point in the image. The depth is found using the focal point, disparity, and the distance between the difference the camera sees on the point.

I was wondering if there is a formula that would convert this point into a (x,y,z) coordinate. I'm stuck because even if the physical location of the point may be different, the camera would reply with a different depth, but same x,y values.

Thanks,
 
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  • #2
isn't the depth the z coordinate? Could you be more specific about what you are imaging, and maybe include some kind of illustration?
 
  • #3
Is this a correct description of the problem ?

You have two identical cameras. The pinholes of those cameras are positioned on the x-axis, the first at the origin, looking along the z-axis, with the second camera, at x = s, with camera 2 optical axis parallel to that of camera 1.

The images from the two cameras each have a cardinal reference point, defined by the intersection of the image and the optical axis. A point object, visible on both images is located relative to the reference point; on image #1 at (x1, y1), and on image #2 at (x2, y2).

Find the position of the point object(x, y, z), given s, and the (x1, y1) and (x2, y2) offsets.

Do you have the distance of the pinhole from the image plane?
 
  • #5
Baluncore, Thats exactly how I should've worded it.
The distance from the pinhole to image plane is roughly about 50cm, but I want it to work for any value.
 
  • #6
steven77723 said:
The distance from the pinhole to image plane is roughly about 50cm, but I want it to work for any value.

The x-coordinate is a function of s.

The z-coordinate is a function of the image plane to pinhole distance.
With a lens, that is the focal length only when focussed at infinity.
Let's be slack and just call it f.

So you must be able to somehow measure or calibrate f, against your camera separation, s.

Draw a view of the object and image placement in the x-z plane and you will see it is ratiometric.
x = s * x1 / (x1+x2), I will let you sort out the sign of the x values.
z = f * ?, and the y = ? values.

See the post#4 references from blainiac.
 
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1. What is the purpose of creating 3d coordinates from stereoscopic images?

The purpose of creating 3d coordinates from stereoscopic images is to accurately map and measure the depth of objects in a 3d space. This can be useful in various fields such as computer graphics, medical imaging, and virtual reality.

2. How do you create 3d coordinates from stereoscopic images?

To create 3d coordinates from stereoscopic images, a process called triangulation is used. This involves identifying corresponding points on each image and using the known distance between the cameras to calculate the depth of the object in the scene.

3. What equipment is needed to capture stereoscopic images for creating 3d coordinates?

To capture stereoscopic images, you will need at least two cameras with a known distance between them. This can be achieved with special cameras designed for stereoscopic imaging, or by using two regular cameras mounted on a rig. Additionally, you will need software to process and align the images.

4. Are there any limitations to creating 3d coordinates from stereoscopic images?

There are a few limitations to creating 3d coordinates from stereoscopic images. Firstly, the accuracy of the results depends on the quality of the images and the calibration of the cameras. Additionally, objects that are too close or too far from the cameras may not be accurately captured. Lastly, movement or changes in the scene can also affect the accuracy of the 3d coordinates.

5. How can 3d coordinates from stereoscopic images be used in research or applications?

3d coordinates from stereoscopic images have a wide range of applications. In research, they can be used for studying the structure and movement of objects in 3d space. In applications, they can be used for creating 3d models, virtual reality experiences, and for medical imaging and diagnostics. They can also be used for depth perception in autonomous vehicles and robotics.

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