About 3D coordinate system of cameraCalibrationData.extrinsicMatrix

I would like to ask about cameraCalibrationData.extrinsicMatrix translation 3x1 column vector data.

I am using iPhone X(iOS11.4.1). In dual camera dual photo delivery mode, wide-area photo's extrinsicMatrix translation 3x1 column vector data indicates [-13.3001, -0.00406908, 0.0237064]. So it means that wide-area camera(lower position)' position is translated to [-13.3001, -0.00406908, 0.0237064] compared to the reference camera(telephoto camera(upper position)). So, introduced 3D coordinate system's X axis direction will be from bottom to top of the iPhone device.

Is it correct?