Wide angle lenses calibration with Opencv

Question

I\'m using a wide-angle lens (178º Diagonal FOV ) and I\'m trying to calibrate it properly using Opencv Calibration module. All the detection and calibration process are working

Answer 1

OpenCV 2.4.10 and above have fisheye camera calibration module. But this module uses a method based on pin-hole camera model. In this model we have an angle between an optical axis of camera and ray of light from some object in front of camera. We also have an angle between optical axis and direction to point on undistorted image (corresponding to object). If calibration was performed correctly, these 2 angles will be equal. It means that if FOV of your camera is about 180 degrees, the distanse from center of undistorted image to edge of undistorted image will be equal to infinity. As a result OpenCV fisheye correction module (cv::fisheye) undistorts only a central part of image. In my own results I got 140-150 degrees FOV in undistorted image. More detailed explanation I placed HERE. If FOV about 140-150 degrees is suitable for you, you can use cv::fisheye without any modification