4
votes
Camera Calibration - why do you have to move the calibration board?
This is due to the optimization problem being rather high-dimensional (around 11 parameters). With only a single observation of the calibration board, there would be multiple possible combinations of ...
- 146
3
votes
How to estimate radial distortion from lens characteristics?
There is a lot of variability because distortion can be compensated for optically and lens designs differ. Some lenses are marketed as rectilinear, most not. You would be making the distortion worse ...
- 13.5k
2
votes
Accepted
Pinhole camera model from houdini parameters
This is a long topic to fully explain. I will try to write shortly, so please excuse the brevity.
Standard computer vision projection (ignoring distortion like Houdini) follows:
$$
\mathbf{x} = \...
- 5,465
2
votes
Accepted
What are the parameters of a calibrated spherical camera?
...if we have a pinhole camera model several parameters describe the specific camera (such as aspect-ratio, focal length, principal point, distortion parameters etc).
"Distortion parameters" does not ...
- 10.6k
2
votes
Accepted
Camera calibration vs. registration
There is no matrix that maps a pixel in camera 1 to the corresponding pixel in camera 2. This is because the location of the corresponding pixel depends on the 3-D location of the corresponding point ...
- 5,091
2
votes
Calibration using Camera Calibration Toolbox for Matlab vs OpenCV
Depending on the lens-distortion model used, the achievable accuracy can be significantly different: https://discorpy.readthedocs.io/en/latest/tutorials/methods.html
Have a go with another approach ...
- 21
2
votes
Fixing distortion in photographic reproductions
I answered a related question in SO some time ago. Briefly, you can work your setup through a standard camera calibration procedure, and you have the option of "freezing" the focal length to ...
2
votes
Camera sensor artifacts next to edges in calibration images; what is causing these?
Probably not a definitive answer, but as close to one as I can get after various tests:
It is not exposure. Over-exposure/saturation only makes the problem more easily visible. Though hard to see, ...
- 41
1
vote
Camera calibration matrix, fundamental matrix and essential matrix at different image resolutions
When you reduce the image resolution, the camera calibration matrix will also change by half. The fundamental matrix will remain unchanged, but the essential matrix will change depending on the camera ...
- 11
1
vote
Accepted
Projection Matrix -- where does it come from?
Theoretically, the intrinsic parameters of the camera, i. e. things like the focal length, the principal point, and the lens distortion parameters should not change, and thus can be estimated once. ...
- 5,091
1
vote
Accepted
Fixing distortion in photographic reproductions
In a general setting, multiple observations of a calibration target are needed because otherwise the focal length parameter(s) and principle point parameters are coupled so you would not be able to ...
- 146
1
vote
3D-to-3D pose estimation
Found a similar solution from the website below. basically similar to what @lutz is suggesting. Remove translation component and solve for rotation in a least sqaure fashion, then compute translation ....
- 11
1
vote
Camera calibration using checkerboard instead of 3D calibration object
Now with a checkboard given one image, I obtain the internal camera matrix and external kamera matrix.
No, you don't. You get a single coordinate transformation matrix that contains only the ratio ...
- 531
1
vote
Understanding legacy code: Algorithm to remove radial lens distortion
Welcome to SP. I happen to have already answered your question in SO: see point 2 of my answer here.
1
vote
Accepted
Camera Pose Estimation from Vanishing Points
You can use the vanishing points to calibrate the camera.
I recommend reading Chapter 8.6 of Multiple View Geometry in Computer Vision [ http://www.cambridge.org/9780521540513 ]
Even better, if you ...
- 26
1
vote
Camera calibration using multiple images
So here are the answers to the questions:
It's a good question. First, your calibration grid should somehow be "coded". For example, the OpenCV checkerboard pattern is a rectangle and the points are ...
- 5,465
1
vote
Camera Calibration - why do you have to move the calibration board?
Digital cameras sample the incoming optical EM or photonic field with a fixed grid of CCD or CMOS transistors. Since the sampling grid (rectangular or perhaps hexagonal) is not angularly symmetric, ...
- 35.2k
1
vote
Accepted
Camera calibration and extrinsic parameters for perspective transformation
You can bypass all the OpenCV stuff, and create a custom mapping from pixel location to real world location of the form:
$$ x = A_x m^2 + B_x mn + C_x n^2 + D_x m + E_x n + F_x $$
$$ y = A_y m^2 + ...
- 7,522
1
vote
Camera calibration and extrinsic parameters for perspective transformation
For your application, here are the steps I would follow:
Calibrate the camera and obtain the intrinsics - You have obviously done that and corrected for the distortion already. ...
- 5,465
1
vote
computer vision - How to correctly calibrate my camera with a wide angle lens using openCV?
If you haven't followed this tutorial on camera calibration with OpenCV, do it. It's well explained and the code is pretty much ready to go. And if your goal is to calibrate your camera using the ...
- 131
1
vote
Why are two cameras mounted in paralle in stereo application?
When you say cameras are parallel it only means that the center pixels are parallel.
Every pixel has a different angle, and that refers to the overlapping regions you were talking about. Actually ...
- 471
1
vote
the position of image plane in optical imaging
I agree with user lxg that it is a notational difference, as for the pinhole camera we always have:
$$S_2 = f$$
That is not necessarily true for a camera with a lens. A pinhole camera is not the ...
- 13.5k
1
vote
How can we combine 2D image with 3D image for the same sense?
Formally speaking, you would like to extrinsically calibrate the laser scanner to the 2D image. I have taken the liberty to edit your question to reflect that.
Here is how my initial approach would ...
- 5,465
1
vote
Accepted
Which pattern (circle pattern or checkerboard pattern) should be used for automotive camera calibration (fisheye/wide webcam)?
The answer here suggests that checkerboard patterns may yield more accurate (subpixel) calibration results and be more robust.
You may have edited your question because the title asks which pattern ...
- 26
1
vote
Accepted
How are the scaling parameters included (extracted from) an essential matrix?
The Essential matrix is defined only up to scale, so you cannot extract scale from it. In other words, if you multiply $t$ and all the 3D world points in your scene by a constant factor, the essential ...
- 5,091
1
vote
Obtain motion between image features by means of the homography matrix
First, calibrate your intrinsics: The focal lengths and the principal point. Homography is not really a rigid transformation and rather a mapping of a plane onto another one. What you really need is a ...
- 5,465
Only top scored, non community-wiki answers of a minimum length are eligible