Depth Sensors Comparison

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Depth Sensors Support

iPi Recorder supports the following depth sensors:

Azure Kinect (Kinect for Azure)
Kinect 2 (Kinect for XBOX One)
Orbbec Astra (PRO)
Intel RealSense D415 and D435
ASUS Xtion 2
Microsoft Kinect for Windows
ASUS Xtion Live
ASUS Xtion
PrimeSense Carmine 1.08

First generation depth sensors are almost outdated but still usable. For example, Orbbec Astra (PRO) has totally the same depth quality and resolution as these outdated sensors. For this reason you can use for example MS Kinect v1 sensor(s) and get exactly the same results as with Orbbec Astra sensor(s). If needed you can find more information about these sensors in documentation for previous version of iPi Motion Capture.

As to modern depth sensors, Azure Kinect sensor is the best choice for full body motion capture, while MS Kinect 2 (Kinect for XBOX One) sensor is also good enough. The quality and accuracy of depth maps from Azure Kinects and MS Kinects 2 are the best in market.

Important.png
Important! Multiple MS Kinect 2 (Kinect for XBOX One) sensors can be connected to a PC with libfreenect2 library. With Microsoft SDK v2, each Kinect should be connected to a separate computer and Distributed Recording utilized.

Comparison

Main features of depth sensors:

Place Sensor Price (approx) Technology Depth FOV (vertical) Depth Resolution Depth FPS Interface Multiple Sensors per single PC External Power Supply Tripod Mount
1 Azure Kinect $400 Time-of-Flight NFOV: 65°
WFOV: 120°
NFOV: 640x576 (very good quality!)
WFOV: 512x512
30 USB 3.0 yes optional yes (1/4″)
2 Kinect 2 (Kinect for XBOX One) $160 Time-of-Flight 60° 512x424 (good quality) 30 USB 3.0 yes required yes (1/4″)
3 First-gen depth sensors from $30 Infrared Coded Structured Light 45° 640x480 (interpolated, actual: 320x240 or even less) 30 USB 2.0 yes not required (except Kinect v1) no
4 Orbbec Astra (PRO) $160 Infrared Coded Structured Light 45° 640x480 (interpolated, actual: 320x240 or even less) 30 USB 2.0 yes not required yes (M6 not 1/4″)
5 Intel RealSense D435 $180 Infrared Coded Structured Light combined with stereo RGB matching 65.5° (only 42° for RGB) up to 1280x720 (but very noisy, inaccurate and with a lot of artifacts like waves and blur!) up to 90 USB 3.0 yes not required yes (1/4″)
6 ASUS Xtion 2 $270 Time-of-Flight 52° (can be mounted in vertical position for 74°) 640x480 (interpolated: actual is less than 320x240) 30 USB 3.0 yes not required yes (1/4″, dual at bottom and side)

Major Pros and Cons of depth sensors:

Place Sensor Pros Cons
1 Azure Kinect
  • The highest FOV (especially in WFOV mode)
  • High resolution of depth and RGB video
  • Low noise, the best quality and accuracy of point cloud
  • The highest overall tracking and calibration quality can be expected
  • Good feet tracking
  • Low mutual sensors interference
  • More tolerant to lighting conditions
  • Supports external synchronization (for ideal sync of multiple devices)
  • Has settings for RGB camera (calibration video can be recorded in light room)
  • Multiple sensors can be connected to one and the same computer
  • Has mount for tripod
  • High price
  • Short USB-cables (use active USB 3.0 repeaters to overcome this drawback)
  • Doesn't like certain fabrics (e.g. shiny)
  • Requires USB 3.0 controller
  • Requires Windows 10 64-bit (doesn't work in Windows 7, 8 and 8.1)
2 Kinect 2 (Kinect for XBOX One)
  • Good-enough FOV
  • Relatively high resolution of depth and RGB video
  • Low noise, good-enough quality and accuracy of point cloud
  • High overall tracking quality can be expected
  • Good-enough feet tracking
  • Low mutual sensors interference
  • Rather tolerant to lighting conditions
  • Has mount for tripod
  • Sensor itself is rather bulky
  • There's no settings for RGB camera like Exposition and Gain (thus, for light marker calibration video you have to have rather dark room)
  • Doesn't like certain fabrics (e.g. shiny)
  • Requires USB 3.0 controller and external power supply
  • Does not work on Windows 7 (requires Windows 8 and higher)
3 First-generation Depth Sensors
  • Ensures tracking quality comparable with that of Kinect 2, but hardware requirements are not so strong
  • Requires USB 2.0 controller
  • Multiple sensors can be connected to a single computer
  • Works on Windows 7 and higher
  • Lower FOV
  • Lower resolution
  • Lower accuracy
  • Less tolerant to lighting conditions
  • Higher mutual interference of sensors leads to more noise in case of using several sensors
  • No mount for tripod
4 Orbbec Astra (PRO)
See above (as 1st gen. depth sensors)
Plus:
  • On sale
See above (as 1st gen. depth sensors)
Plus:
  • Higher price compared to 1st gen. sensors
  • Non-standard tripod mount — M6 instead of 1/4″
5 Intel RealSense D435
  • Up to 90 FPS
  • High resolution of depth map
  • Good field-of-view (FOV)
  • Very compact
  • Great tech support, fast fixes, frequent updates
  • Very low quality of depth map (high noise, many artifacts)
  • Multiple sensor configuration is not practical with this sensors because of accuracy and quality of depth map (cannot be calibrated)
  • RGB camera has significantly lower FOV
6 ASUS Xtion 2
  • Time-of-Flight like Kinect 2
  • Good field-of-view (FOV)
  • Can be mounted in vertical position
  • Very compact
  • Extremely low effective resolution of depth map (too small amount of 3D dots)
  • No mapping between RGB and depth
  • With multiple sensors, sometimes mutual interference issues arise.
  • High price

The winners are Azure Kinect and Kinect 2 (Kinect for XBOX One).

First-generation depth sensors and Orbbec Astra (PRO) share the third place.

Note about Intel RealSense D415 and D435

Based on specification Intel RealSense D415 and D435 sensors look very promising. Especially, D435 model which has wider FOV and slightly better quality of depth map.

But actual quality and accuracy of depth map from these sensors are way worse than what we could expect from modern depth sensors:

  • huge waves on relatively flat surfaces
  • thick blur around objects
  • extremely high noise both in spatial and time dimensions

These downsides make Intel sensors almost unusable for full body motion capture tasks.

For this reason we included only D435 model in comparison tables because it's more powerful and advanced compared to D415 but still is not good enough for our needs.

Drivers and Software Libraries

The following sensors don't require special drivers and software to be recognized in iPi Recorder:

  • Azure Kinect
  • Intel RealSense D415 and D435
  • ASUS Xtion 2

That is, you can simply plug in these sensors to computer and make recordings in iPi Recorder without need to install any drivers or SDK's.

Other sensors require special drivers and/or software libraries/SDK to be installed: