Camera calibration "isNAN" assumes that the axis is pixels

In utilities/saveShotToDataset.m we have

            % save x-axis
            xcal = dataset.metadata.camCalibrationsX{i};
            if ~isnan(xcal)
                xaxis = xaxis * xcal;
                unitx = 'mm';
            else
                unitx = 'px';
            end
            dataset.images.(camVars{i}).xaxis = xaxis;
            dataset.images.(camVars{i}).unitx = unitx;

However for the digital cameras, the original xaxis is in mm, but with unknown calibration.