Calibrating iPhone for OpenCV — Square vs Normal images

asked 2020-06-12 06:29:49 -0500

Alice_aj gravatar image

I'm using ArUco with OpenCV to calibrate my iPhone camera and estimate the pose of the marker in the scene. To calibrate the camera, I used the normal (photo) option in the iPhone's camera but then realised that I will need to capture squared images for pose estimation, i.e. using the "square" option in the camera.

I'm wondering if I need to re-calibrate the camera using only squared images? i.e. does the image ratio affect the calibration result?

Also, I will be using the calibration results to find a marker position relative to the camera (i.e. estimatePoseSingleMarkers), I tried it with my current calibration result and drew the axes on top of the detected marker, it seems ok but my problem is that the numbers I'm getting are a bit strange (e.g. the camera is actually 40 cm away from the object centre (y)) but I'm getting a very small number.

Thanks! I hope that my question is clear.

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Comments

does the image ratio affect the calibration result?

yes. so you need to calibrate on the same ratio you want to use later

then realised that I will need to capture squared images for pose estimation,

can you explain why ?

berak gravatar imageberak ( 2020-06-14 02:36:47 -0500 )edit