The Technology Behind The Movie Industry: Gyroscope
We all love movies, right? So how does the cinema industry capture the image well as if we were witnessing the moment with our own eyes? Let’s take a look at the technology behind it.
The word ‘gyroscope’ is a combination of the Ancient Greek words ‘gýros’ which means ‘turning’ and ‘sképō’ which means ‘to observe’. It is a type of physical sensor that detects and measures the angular motion of an object with respect to an inertial reference. What makes gyroscopes so unique is that their ability to measure the absolute motion of an object without any external infrastructure or reference signals.
There are two types of gyroscopes: mechanical and angular.
Mechanical gyros are classified as displacement and velocity gyros. They consist of a mass that rotates around its axis. During this turn, the ball tends to stay parallel to itself and to oppose any attempt to change its direction.
Optical gyroscopes work by sensing the difference in propagation time between laser beams traveling in opposite directions in open or closed optical paths. With a change caused by the rotation of the emitted rays in their path lengths, a phase difference occurs between these counter-emitted rays. This phase difference due to rotation is due to the Sagnac principle, which is the working principle of optical gyroscopes.
Sagnac principle means that the relative phases of two rays emitted oppositely in a ring structure change as the ring in question rotates.
Gyroscopes used in camera stabilization systems in the movie industry are mechanical ones.
We can summarize the basic working principle of a mechanical gyroscope as follows: a mass that tends to maintain its angular position relative to an inertial reference point. When a constant external torque is applied to this mass, the axis of rotation begins its motion at a constant angular velocity in a direction normal to the direction of this torque. The external forces acting on the center of mass of the rotating part do not affect the angular position of the axis of rotation.
If you are interested in this topic and would like to have more technical knowledge, I recommend the following references, which are the sources I used in preparing this text:
- Alexander A. Trusov, “Overview of MEMS Gyroscopes: History, Principles of Operations, Types of Measurements”, University of California, 2011.
- Vittorio M. N. Passaro, Antonello Cuccovillo, Lorenzo Vaiani, Martino De Carlo and Carlo Edoardo Campanella, “Gyroscope Technology and Applications”, 2017.
Pelinsu Erimez
