The purpose of calibration is the estimation of the intrinsic and extrinsic parameters of a camera given one or more calibration pattern. For collecting the image coordinates of the calibration pattern the process of edge detection have to be done. Edge detection is important for specifying the coordinates of the vertices of the squares in the pattern calibration.
Experiment details can be found at: https://www.researchgate.net/publication/281208272_Camera_Calibration