The measurements are in pixels. the x-axis just represents a set of measurements while the y axis is the change in the value of the particular cartesian coordinate. The camera calibration has very low reprojection error for each camera. For each set of messurments am calculating the relative pose for each camera as below:
From there am extracting the change in x,y,z of the camera position which should be the same for each coordinate but somehow the y-coordinate is not consistent. Note that am getting the pose of the camera from a checkerboard pattern using solvePNP. I have no worries about the calibration or pose calculation.