Simplifying stereo camera calibration using M-arrays

Sammanfattning: Digitization of objects in three dimensions, also known as 3D scanning, is becoming increasingly prevalent in all types of fields. Ranging from manufacturing, medicine, and even cultural heritage preservation. Many 3D scanning methods rely on cameras to recover depth information and the accuracy of the resulting 3D scan is therefore dependent on their calibration. The calibration process is, for the end-user, relatively cumbersome due to how the popular computer vision libraries have chosen to implement calibration target detection. In this thesis, we have therefore focused on developing and implementing a new type of calibration target to simplify the calibration process for the end-user. The calibration board that was designed is based on colored circular calibration points which form an M-array, where each local neighborhood uniquely encodes the coordinates. This allows the board to be decoded despite being occluded or partially out of frame. This contrasts the calibration board implemented in most software libraries and toolboxes which consists of a standard black and white checkered calibration board that does not allow partial views. Our board was assessed by calibrating single cameras and high FOV cameras and comparing it to regular calibration. A structured light 3D scanning stereo setup was also calibrated which was used to scan and reconstruct calibrated artifacts. The reconstructions could then be compared to the real artifacts. In all experiments, we have been able to provide similar results to the checkerboard, while also being subjectively easier to use due to the support for partial observation. We have also discussed potential methods to further improve our target in terms of accuracy and ease of use.