# Tag Info

### camera calibration: why chessboards?

This is mostly a matter of history. Checkerboard patterns have proven in the past to: yield calibration accurate results be easy and robust to implement. This was confirmed (for example) by a ...
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### Is it possible to hack camera calibration without having access to the camera?

If I understand correctly, you don't need the intrinsics or extrinsics to achieve that, if a top-down view is all you want. You could basically define 4 points on your parallel lines and then warp the ...
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### camera calibration: why chessboards?

You can use any target you'd like as long as you can find the features in a robust way, and you know their location in the real world. For example I used once ISO12233 chart image to calibrate radial ...
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### 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 ...
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### Can you average out focal length from different camera calibration sessions?

No, it is not a good idea. Typically, you want to limit the volume of space relative to the camera in which you want to do your measurements, and you want to use a single calibration target ...
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### Image processing and Camera Calibration

Yes, the center pixel and focal length in pixels will change, as described in the link above. However, if you learn distortion parameters (radial and tangential) then they shouldn't change as ...
Accepted

### How does chessboard configuration affect camera calibration?

Generally speaking, when you are estimating a model from data, the more (independent) data points, the better the estimation. In this particular case, the goal is to get as many 3d -> 2d point ...

### Camera Calibration using Single Input Image

Take a look at this paper here: "Straight lines have to be straight" by Faugeras et al. http://link.springer.com/article/10.1007/PL00013269#page-1 It is straight forward to implement, but essentially ...
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### Camera calibration using multiple images

You are correct: to calibrate a camera you need a correspondence between 3D world points and 2D image points. The problem is that the 3D points cannot be co-planar, so people were building 3D ...
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### 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 ...
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### Pinhole calibration

It is possible to invert the mapping, but projecting a 2D image point into 3D world won't give you a single point but a ray, which is the locus of all 3D world points that map to the same point in the ...
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### Changing camera and image properties to calibrate a camera

You should not experience any major drawbacks. Generally such techniques utilize adaptive thresholds and rely on gradient orientations (especially normalized ones), which are intrinsically invariant ...
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### How to calibrate three orthogonal cameras？

For pairwise stereo calibration try using the Stereo Camera Calibrator app in the Computer Vision System Toolbox. It is much easier to use than Caltech Camera Calibration toolbox. For starters it ...
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### How to calibrate three orthogonal cameras？

Use an asymmetric calibration plate. Such as the new circle grid in OpenCV. Check here. You do not need to find the correspondences in the gui, but rather run the calibration directly. Also, do not ...
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