Simple calibration

Open again a test image in 'UVMAT_DEMO_FILES/EX01_pair'. We shall use the diameter of the half cylinder visible on the upper let of the image to set the calibration. Its physical diameter is 2cm. The corresponding diameter in pixels can be obtained with the ruler displayed by the menu bar Tools/ruler of uvmat.

First zoom on the cylinder to optimize the precison. Select zoom on, press the left mouse button and adjust the field with the directional key board arrows. Then unselect zoom on to allows for other mouse actions (otherwise zoom has priority).