WHAT IS MOTION CAPTURE

There are many different approaches to motion capture. But what’s the difference?

Types of motion capture

• Optical-Passive. This technique uses retroreflective markers that are tracked by infrared cameras. It is the most flexible and common method used in the industry.
• Optical-Active. This technique uses LED markers that emit light that are tracked by special cameras. Because of this they need a battery or charger of some kind.
• Video/Markerless. This technique does not require markers and instead relies on software to track the subjects’ movement. Varying tracking methods yield different results, but real-time and final data error ranges tend to be larger than marker-based solutions.
• Inertial. This technique does not require cameras except as a localization tool. Inertial sensors (sometimes known as IMUs) are worn by the subject and the data from the sensors is transmitted wirelessly to a computer or smart device.

Passive optical motion capture is the most accurate, flexible and common type of motion capture and is a major technology for Vicon. Within the passive optical market there are a variety of features to choose from, so let’s look at what goes into a passive optical system.

All motion capture systems’ fundamental accuracy starts with the resolution and quality of the camera sensor. It is what ‘describes’ the markers to the system – essentially the higher the resolution of the sensor, the more detail you obtain from the marker. This is particularly important if your application requires precision tracking – small markers, such as facial tracking, or markers that are close together, such as gait analysis or modeling the foot of a child.

In short, yes. A high camera speed is important for any application that involves subjects moving quickly or in a very subtle, nuanced way. For example sports movements, golf swing analysis or measuring muscle deformity.

Software is another key component of your system – not only because this will be your main point of interaction with the cameras and all other components, but because it is the main processing tool for all of your 2D and 3D data. Capturing a day’s worth of data only to discover that it requires three weeks of clean up, or there are too many gaps in the trajectories to make the data valid, means time and money wasted.

The precision and repeatability of your data is dependent on your system calibration. The LEDs on Vicon’s Active Wand are machined placed and precision engineered to give you a more precise overall calibration.

The Active Wand calibrates both optical and video cameras while accounting for sensor edge distortion at the same time, to ensure synchronized overlay across your entire volume.

Reference video in motion capture provides a means to validate your data with a visual representation of what happened on the day. It can help an animator better reflect the nuance of a performance, or a clinician validate the data they are analyzing.

Your sync box provides a single communication point between your cameras and PC. If you’re not integrating third-party equipment like reference video or force plates into your system, this could be as simple as a POE switch.

The real difference with the various sync boxes offered by manufacturers comes when you need to integrate fully synchronized third-party devices or require timecode. Vicon’s Lock+ sync box offer many features such as Timecode, Genlock, VESA and synchronized triggering of your third-party devices.

The capture and display of motion capture data is a highly demanding task for a PC. HD reference footage creates a huge amount of data, and displaying graphical information in 3D and real-time data processing asks a lot of the processor. The PC specification for your system will be recommended by your motion capture vendor, but as a guide, Vicon’s recommended specification can be found HERE.

There’s a difference between a company that builds and a company that creates. For us, that difference is innovation, and it is at the core of everything we do. Our development team has been awarded research funding by the UK government for the development of innovative motion capture technologies, which will ultimately help put our customers one step ahead of the rest.

Precision engineering is what we do. From custom built sensors with electronic freeze frame shutters, high sensitivity pixels, synchronized reference video, and calibration devices, every part of a Vicon system is designed to give you the most precise data possible. Learn more HERE.

Ten years ago, learning to use any motion capture system could take more than two weeks of training. Now, a Vicon Support Engineer will have you up and running in a day. From calibration to data capture, our software takes you through a simple step-by-step process to get you the highest quality data.

Vicon systems are in widespread use all over the world. This community has thrived, exchanging ideas and experiences for many years. Partnering with Vicon will ensure new members immediately benefit from a broad existing knowledge base.

We believe our support engineers should have an intimate knowledge of the science, not just the technology. That’s why our industry leading customer support team consists of application specialists, including several PhDs.

Vicon develops and manufactures the world’s only passive optical motion capture systems that are classed as Medical Devices, as certified by a notified body under ISO 13485. Vicon is also ISO 9001 compliant, indicating the adherence to strict procedures and guidelines, producing CE marked products, along with a Declaration of Conformity, that confirms the standards of the Medical Devices Directive are fulfilled.