Introduction

• CV based: occlusion issues(遮挡问题), limited to the view of the camera
• IMU: low-cost and occlusion-free; require frequent calibrations
• strain gauge: strain gauge may shift

Related Work

Computer Vision-Based Approaches

• infrared camera(红外摄像头)
• depth camera

On-Body Sensing

• EMG
• electric field

Indirect Sensing

• 2.4 GHz
• Doppler-shifted signals

These techniques usually require accurate sensor calibration to obtain sufficient signal-to-noise ratios (SNR). They also rely on signal reflections from the human body and hence suffer from occlusion issues.

Magnetic Field Sensing

• Razer Hydra(MF+IMU): 需要产生3维磁场，导致很笨重
• Polhemus 使用磁场梯度，导致必须在静止状态下使用

还有一些其它的设备，但是这些技术要么需要使用较大的传感器阵列，要么只能支持2D定位。