Biomechanical Analysis

Introduction

Starting from version 2.6, iPi Mocap Studio includes iPi Biomech Extension.

iPi Biomech Extension is a convenient tool for in-depth biomechanical analysis on tracking data. It includes visualization of tracking data and its export to various formats. It can be used for:

• Gait analysis and rehabilitation
• Sports motion analysis
• Research in 3D human kinematics

Markerless tracking technology does not require clumsy suits, and work in real-life environments like regular office.

With iPi Biomech Extension you can: Get Linear and Angular Quantities for selected bones, including Linear coordinate, velocity, acceleration Euler angles, angular velocity and acceleration Select convenient coordinate systems Linear: Absolute (relative to floor), Relative to parent joint, Relative to center of mass Angular: Absolute (relative to floor), Relative to parent joint Plot values of selected metrics Export bones motion data to file Tab-separated text (for Excel) MATLAB Export point clouds obtained from depth sensors to file PCD MATLAB

Note. iPi Biomech Extension requires separate license key, which you need to activate in addition to iPi Mocap Studio license key. 30-days free trial provided.

Glossary

Linear quantities

Quantities derived from linear coordinate of joint in which bone is connected to parent bone, includes

• Coordinate
• Velocity
• Acceleration

Angular quantities

Quantities derived from Euler angle bone

• Euler angle
• Angular velocity
• Angular acceleration

Batch Step (or just Step)

Element of batch. Consists of the following information:

• Input Mocap project file name
• Output Mocap project file name (by default is the same as input)
• Processing Pass (see above)
• Values of Parameters of the Pass
• Current Timeline Position (or just Frame)
• Region-of-Interest

Batch

Sequence of Batch Steps. Can be saved to disk, loaded from disk, executed.=== License and Trial ===

iPi Biomech Extension requires separate license key, which you need to activate in addition to iPi Mocap Studio license key. You can order your license here, or activate 30-days free trial. As soon as you install (or auto-update to) version 2.6 or higher, Biomech tab will appear in iPi Mocap Studio control panel. Follow the steps below to start working with iPi Biomech Extension

1. Switch to Biomech tab.
2. Press Activate button
3. Press Start 30-days Free Trial Period or Enter Biomech License Key and follow further on-screen instructions

   

Note. If you do not have iPi Mocap Studio license key, you can order it here or activate 30-days free trial. If your Studio trial has expired, you will not be able to export biomech data as well as animation. But you can still plot biomech data.

Select Data for Analysis

First you need to select data that you will analyze

1. Select bones
   • (1) Check corresponding bones to include them in analysis
   • (2) On the top of the list you can see "special" bones - Center of mass, Center of mass projection to the ground. The rest of the list are bones from internal iPi rig.
   • (3) You can include finger bones into analysis by expanding hand bone (RHand and / or LHand). However, fingers are not tracked due to insufficient resolution of off-the-shelf cameras, so they just keep attached to hand joint (RHand or LHand), remaining in default position related to hand
   • (4) You can select all bones by clicking to checkbox in the header. Fingers will be included only if hand bone is expanded.
   • (5) You can change bones listbox height using splitter at the bottom.

   

2. Select linear quantities for analysis
3. Select output units for each quantity
4. Select linear coordinate system
5. Select angular quantities for analysis
6. Select output units for each quantity
7. Select angular coordinate system