There is no straightforward answer to the questions which is better — Multiple Depth Sensors or Multiple Web Cameras or Multiple Action Cameras configuration. The accuracy of tracking is almost the same. Pros and cons summary:
| Cameras/Sensors |
Pros |
Cons
|
| Multiple Depth Sensors (2 to 4 depth sensors) |
- Easier to set-up and calibrate
- Require less space due to wider angle of view, minimum required space is 7 x 4 feet ( = 2.2 x 1.2 meters)
- Real-time Tracking for Live Preview feature
- No requirements to clothes color
|
- Capture area is limited with 7 x 7 feet ( = 2 x 2 meters)
- Framerate is only 30 fps (more tracking errors on fast motions)
- More problems with occlusion (especially for complex motions including rotations)
- Kinect 2 (Kinect for XBOX One) sensors require a separate PC for each sensor for recording
- Cannot be used outdoors
|
Web Cameras (3 to 16 cameras)
Sony PS3 Eye or Logitech C922 |
- More accurate tracking for head and feet (in comparison with depth sensors)
- Bigger capture area (in comparison with depth sensors), up to 20 by 20 feet ( = 7 by 7 meters)
- 60 fps framerate allow to track fast motions
- Less problems with occlusion (especially for more than 6 cameras)
- Allows outdoor capture (not in sunny weather though)
- Relatively low price
|
- Set-up and calibration takes more time
- More issues with USB controllers (you need 3 USB controllers for 6 cameras, and 4 USB controllers for 8 cameras)
- You need more space, minimum required space is 13 x 13 feet ( = 4 x 4 meters)
- Higher requirements for HDD speed
- A lot of USB cables on the floor
|
| Action Cameras (3 to 16 cameras) |
- No need in PC and external power supply for recording (high mobility)
- No USB cables on the floor
- Wider view angle (FOV) results in bigger capture volume (in comparison with web cameras)
- Wider view angle allows to record in smaller rooms (in comparison with web cameras)
- 90 and even 120 FPS (depends on the model of action camera and lighting conditions)
|
- Intrinsic parameters of each camera must be determined in advance (camera optics calibration)
- A few manual and time consuming steps are required to get multi-camera synchronized video:
- Right now there is no simple way to use Motion Controllers with action cameras
|
If you choose to go with depth sensors, see also the comparison of different models.
General Recommendations
- Dual Depth Sensor configuration is very practical, it is easier to use and able to track many kinds of motions. We can recommend it if:
- Your room is not very big (less than 20 x 20 feet = 6 x 6 meters)
- You do not need to track fast complex motions like energetic dancing, acrobatics, etc.
- You do not need to track 2 actors
- Multiple Web Cameras (Sony PS3 Eye or Logitech C922) is more powerful option, but you have to invest more time in learning. We can recommend it if:
- 7 x 7 feet ( = 2 x 2 meters) capture area is not enough for your motions, and your room is bigger than 20 x 20 feet ( = 6 x 6 meters)
- You plan to track fast complex motions like energetic dancing, acrobatics, etc.
- You plan to track 2 actors
- Multiple Action Cameras configuration is almost similar to multiple web cameras configuration but involves more tricky workflow. We recommend it if:
- You already have required set of action cameras
- You want to be extremely mobile
- You're going to capture very fast motions at 90+ FPS