Ideal Pinhole Camera consistency
Hi All
I am attempting to get the ideal pinhole camera for the camera of an iPad Mini 4. I have done multiple calibration sessions using a chessboard pattern and code from: https://docs.opencv.org/master/dc/dbb...
The issue I have is the consistency. I have used up to 200 images per session. The checkerboard is detected in all of them. The resolution of the images is 2448 × 3264 Auto-focus is turned off.
I find the deviation rather large, for the same camera.
fov_deg 59.2862
fov_deg 60.6048
fov_deg 59.9288
f_x 2913.33
f_x 2907.07
f_x 2933.18
f_y 2914.59
f_y 2901.48
f_y 2930.74
c_x 1238.07
c_x 1282.58
c_x 1275.43
c_y 1605.38
c_y 1568.35
c_y 1574.36
Is this expected? Which accuracy is realistic? Am I missing something?
This data is later used for 3D reconstruction, so it should be as accurate as possible.
Looking forward to your insights
Best regards Wim
Edit: added info about auto-focus Edit2: corrected image resolution
I _think_ that is expected, especially if the pinhole is an attachment over the device's autofocus optics. The device's camera is so small and its chassis flexible that even slight vibrations and warming of the device would cause such deviation. And for pinhole photography it might not matter much...
The pinhole in photography is used but the problem here is the autofocus from my perspective, i Think. And yeah, moreover there are also other problems, from my study the only problem about the temperature is the position of the piercing point in most of the camera and it start to be important when the temperature change of about 30 degrees. There is a paper about that. For this case it seems to be completely wrong. cx it is around 1238, sound strange to me...
Hi, forgot to mention that autofocus is turned off here. The image resolution is wrong, it must be 2448 × 3264