VR & AR Wiki - User contributions [en]

Inside-out tracking

2017-07-19T13:24:50Z

Chelnov: Added system.

{{stub}}
{{see also|Marker-less, Inside-Out Tracking‎|Positional tracking}}
[[File:Inside out vs. outside in tracking.png|thumb|Figure 1. Inside-out vs. outside-in tracking (Image: Ishii, 2010)]]
[[File:F2Ak4iE.jpg|thumbnail|Figure 2. Early [[Lighthouse]] prototype, an inside-out tracking system with QR codes as [[fiducial markers]].]]
[[File:Acer mixed reality headset inside-out.png|thumb|Figure 3. Inside-out tracking HMD (image: www.wareable.com)]]

==Introduction==
Inside-out tracking is a method of [[positional tracking]] commonly used in [[virtual reality]] (VR) technologies, specifically for tracking the position of [[head-mounted display|head-mounted displays]] (HMDs) and motion controller accessories. It differentiates itself from [[outside-in tracking]] by the location of the cameras or other sensors that are used to determine the object’s position in space (Figure 1). In inside-out positional tracking, the camera or sensors are located on the device being tracked (e.g. HMD) while in outside-out the sensors are placed in a stationary location. <ref name=”1”> Ribo, M., Pinz, A. and Fuhrmann, A.L. (2001). A new optical tracking system for virtual and augmented reality applications. Instrumentation and Measurement Technology Conference Proceedings</ref> <ref name=”2”> Boger, Y. (2014). Positional tracking: "Outside-in" vs. "Inside-out.” Retrieved from http://vrguy.blogspot.pt/2014/08/positional-tracking-outside-in-vs.html</ref> <ref name=”3”> Ishii, K. (2010). Augmented Reality: Fundamentals and nuclear related applications. Nuclear Safety and Simulation, 1(1)</ref>

A VR device using inside-out tracking looks out to determine how its position changes in relation to the environment. When the headset moves, the sensors readjusts its place in the room and the virtual environment responds accordingly in real time. This type of positional tracking can be achieved with or without markers placed in the environment. The latter is called [[markerless inside-out tracking]]. <ref name=”4”> Langley, H. (2017). Inside-out v Outside-in: How VR tracking works, and how it's going to change. Retrieved from https://www.wareable.com/vr/inside-out-vs-outside-in-vr-tracking-343</ref>

The cameras (or any other optical sensors) that are placed on the HMD observe features of the surrounding environment. When using markers, these are designed to be easily detected by the tracking system and placed in a specific area. These [[fiducial markers]] include primitive shapes like points, squares, and circles (Figure 2). QR codes are an example of positional markers that can be placed in the outside world to serve as reference points for the tracking camera. Inside-out positional tracking can also be achieved using infra-red (IR) markers and a camera that is sensitive to this type of light. In case of using markers, the inside-out system works only as long as it can detect the markers. If these are out of its field of view, positional tracking will be affected. <ref name=”2”></ref> <ref name=”3”></ref> <ref name=”5”> Mehling, M. (2006). Implementation of a Low Cost Marker Based Infrared Optical Tracking System. PhD thesis, Fachhochschule Stuttgart</ref>

With markerless inside-out tracking - a method based on natural features - uses distinctive characteristics that originally exist in the environment to determine position and orientation. The system’s algorithms identify specific images or shapes and uses them to calculate the device’s position in space. Data from accelerometers and gyroscopes can also be used to increase the precision of positional tracking. <ref name=”3”></ref> <ref name=”6”> Boger, Y. (2014). Overview of positional tracking technologies for virtual reality. Retrieved from http://www.roadtovr.com/overview-of-positional-tracking-technologies-virtual-reality/</ref>

==Devices using inside-out tracking==
* ''See also: [[Markerless, inside-out tracking#Markerless inside-out tracking Devices|Devices using markerless inside-out tracking]]''

'''[[HTC Vive]] (including [[HTC Vive Developer Editions|developer editions]])'''

'''Nintendo Wii Remote (not officially used for VR)'''

==Inside-out tracking systems==
* ''See also: [[Markerless, inside-out tracking#Markerless, inside-out tracking Systems|Systems using markerless inside-out tracking]]''

'''[[Lighthouse]] - [[SteamVR]]'''

'''Nintendo Wii Sensor Bar (not officially used for VR)'''

[[Category:Terms]] [[Category:Technical Terms]]

==References==

Outside-in tracking

2017-07-19T13:22:32Z

Chelnov: /* Devices using outside-in tracking */ Removed brand to match "PlayStation VR".

{{stub}}
{{see also|Positional tracking}}
==Introduction==
[[File:Outside in tracking.png|thumb|Figure 1. Outside-in tracking (Image: www.wareable.com)]]
[[File:Inside out vs. outside in tracking.png|thumb|Figure 2. Inside-out vs. outside-in tracking (Image: Ishii, 2010)]]

Outside-in tracking is a form of [[positional tracking]] and, generally, it is a method of optical tracking. When referring to [[virtual reality]] (VR), tracking is the process of tracing the scene coordinates of moving objects in real-time, such as [[head-mounted display|head-mounted displays]] (HMDs) or motion controller peripherals. <ref name=”1”> Ribo, M., Pinz, A. and Fuhrmann, A.L. (2001). A new optical tracking system for virtual and augmented reality applications. Instrumentation and Measurement Technology Conference Proceedings</ref>

Outside-in VR tracking uses cameras or other sensors placed in a stationary location and oriented towards the tracked object (e.g. a headset) that moves freely around a designated area defined by the intersecting visual ranges of the cameras (Figure 1). The object is therefore observed from outside by the fixed tracking device. Usually, the tracked object has a known set of markers that are essential for the calculation of its position relative to the sensors. Also, while this type of positional tracking can be achieved using the visible light spectrum, it is common to use infra-red (IR) markers and cameras that can detect that type of light. <ref name=”1”></ref> <ref name=”2”> Mehling, M. (2006). Implementation of a Low Cost Marker Based Infrared Optical Tracking System. PhD thesis, Fachhochschule Stuttgart</ref> <ref name=”3”> Boger, Y. (2014). Positional tracking: "Outside-in" vs. "Inside-out.” Retrieved from http://vrguy.blogspot.pt/2014/08/positional-tracking-outside-in-vs.html</ref>

The majority of commercially available optical trackers use outside-in tracking. Its accuracy and performance are dependent on various factors like optical sensors, tracking markers and targets, processing power, and tracking algorithms, all of which can vary greatly. <ref name=”2”></ref> <ref name=”4”> Wang, J.F., Azuma, R., Bishop, G., Chi, V., Eyles, J. and Fuchs, H. (1990). Tracking a head-mounted display in a room-sized environment with head-mounted cameras. Proceedings of SPIE 1990 Technical Symposium on Optical Engineering and Photonics in Aerospace Sensing, Orlando, Florida</ref>

Outside-in tracking using markers is a well-developed and researched technology. Indeed, a group of researchers (Pustka et al., 2012) built a positional tracking system of this kind using only unmodified off-the-shelf mobile phones. Also, an early two-camera tracking system was described by Madritsch and Gervautz in 1996, and a system that used synchronized IR cameras, able to distinguish 6D targets, was described by Dorfmüller in 1999. <ref name=”5”> Pustka, D., Hülb, J.P., Willneff, J., Pankratz, F., Huber, M. and Klinker, G. (2012). Optical Outside-In Tracking using Unmodified Mobile Phones. IEEE International Symposium on Mixed and Augmented Reality</ref>

The main VR systems in the market - [[Oculus Rift]], [[HTC Vive]], and [[PlayStation VR]] - all use outside-in VR tracking. In each case, headsets and accessories are tracked by an external device. The Oculus Rift positional tracking ([[Constellation]]) is achieved by placing an optical sensor pointed at the headset, with the PlayStation VR having a similar setup. In the case of the HTC Vive, tracking is achieved with the [[Lighthouse]] sensors that are placed around the area to be tracked. While this kind of setup is mainly applied to higher-end VR systems, there have been some experiments with outside-in tracking applied to mobile VR. <ref name=”6”> Langley, H. (2017). Inside-out v Outside-in: How VR tracking works, and how it's going to change. Retrieved from https://www.wareable.com/vr/inside-out-vs-outside-in-vr-tracking-343</ref>

The outside-in tracking system needs room calibration after the cameras or sensors are placed, and the data acquired by the system is processed on a computer. <ref name=”3”></ref> <ref name=”5”></ref> Besides its application in VR, this type of tracking is used in motion capturing, as in the case of the film industry. <ref name=”2”></ref>

Outside-in tracking functions as the inverse of [[inside-out tracking]] (Figure 2). While the former places the sensors in a stationary location to track the VR goggle, in the latter the sensors are placed on the goggles and the markers in stationary locations. <ref name=”3”></ref> <ref name=”7”> Ishii, K. (2010). Augmented Reality: Fundamentals and nuclear related applications. Nuclear Safety and Simulation, 1(1)</ref>

==Pros and Cons of outside-in tracking==
At the moment, outside-in tracking has the best accuracy, with the possibility of adding more sensor trackers in the room to further increase it. The latency is also better with this type of tracking, reducing the probability of the user feeling nauseous. Nevertheless, outside-in systems do have limitations, mainly due to occlusion. This occurs when the cameras or sensors cannot track the object because it is out of their line of sight, which leads to tracking errors. <ref name=”6”></ref> <ref name=”8”> Welch,G. and Foxlin, E. (2002). Motion tracking: No silver bullet, but a respectable arsenal. IEEE Computer Graphics and Applications</ref>

==Future of outside-in tracking==
Outside-in tracking is expected to continue to be the main tracking technology in high-end VR systems as the best all-around solution. This market is likely to be the last to move towards the inside-out tracking technology. Other technologies like [[redirected walking]] could also have a great impact in VR positional tracking, further improving the characteristics of outside-in tracking. <ref name=”6”></ref>

==Devices using outside-in tracking==

'''[[Oculus Rift|Rift]]''' (including [[Oculus Rift DK2|Rift development kit]])

'''[[PlayStation VR]]'''

==Tracking systems using outside-in tracking==

'''[[Constellation]]'''

'''[[PlayStation Camera]]'''

'''[[Neon Tracking System]]''' (used by [[HTC Link]]<ref>[http://www.roadtovr.com/htc-link-headset-ximmerse-neon-tracking-details/]]</ref>)

[[Category:Terms]] [[Category:Technical Terms]]

==References==

Outside-in tracking

2017-07-19T13:19:38Z

Chelnov: Re-ordered list.

{{stub}}
{{see also|Positional tracking}}
==Introduction==
[[File:Outside in tracking.png|thumb|Figure 1. Outside-in tracking (Image: www.wareable.com)]]
[[File:Inside out vs. outside in tracking.png|thumb|Figure 2. Inside-out vs. outside-in tracking (Image: Ishii, 2010)]]

Outside-in tracking is a form of [[positional tracking]] and, generally, it is a method of optical tracking. When referring to [[virtual reality]] (VR), tracking is the process of tracing the scene coordinates of moving objects in real-time, such as [[head-mounted display|head-mounted displays]] (HMDs) or motion controller peripherals. <ref name=”1”> Ribo, M., Pinz, A. and Fuhrmann, A.L. (2001). A new optical tracking system for virtual and augmented reality applications. Instrumentation and Measurement Technology Conference Proceedings</ref>

Outside-in VR tracking uses cameras or other sensors placed in a stationary location and oriented towards the tracked object (e.g. a headset) that moves freely around a designated area defined by the intersecting visual ranges of the cameras (Figure 1). The object is therefore observed from outside by the fixed tracking device. Usually, the tracked object has a known set of markers that are essential for the calculation of its position relative to the sensors. Also, while this type of positional tracking can be achieved using the visible light spectrum, it is common to use infra-red (IR) markers and cameras that can detect that type of light. <ref name=”1”></ref> <ref name=”2”> Mehling, M. (2006). Implementation of a Low Cost Marker Based Infrared Optical Tracking System. PhD thesis, Fachhochschule Stuttgart</ref> <ref name=”3”> Boger, Y. (2014). Positional tracking: "Outside-in" vs. "Inside-out.” Retrieved from http://vrguy.blogspot.pt/2014/08/positional-tracking-outside-in-vs.html</ref>

The majority of commercially available optical trackers use outside-in tracking. Its accuracy and performance are dependent on various factors like optical sensors, tracking markers and targets, processing power, and tracking algorithms, all of which can vary greatly. <ref name=”2”></ref> <ref name=”4”> Wang, J.F., Azuma, R., Bishop, G., Chi, V., Eyles, J. and Fuchs, H. (1990). Tracking a head-mounted display in a room-sized environment with head-mounted cameras. Proceedings of SPIE 1990 Technical Symposium on Optical Engineering and Photonics in Aerospace Sensing, Orlando, Florida</ref>

Outside-in tracking using markers is a well-developed and researched technology. Indeed, a group of researchers (Pustka et al., 2012) built a positional tracking system of this kind using only unmodified off-the-shelf mobile phones. Also, an early two-camera tracking system was described by Madritsch and Gervautz in 1996, and a system that used synchronized IR cameras, able to distinguish 6D targets, was described by Dorfmüller in 1999. <ref name=”5”> Pustka, D., Hülb, J.P., Willneff, J., Pankratz, F., Huber, M. and Klinker, G. (2012). Optical Outside-In Tracking using Unmodified Mobile Phones. IEEE International Symposium on Mixed and Augmented Reality</ref>

The main VR systems in the market - [[Oculus Rift]], [[HTC Vive]], and [[PlayStation VR]] - all use outside-in VR tracking. In each case, headsets and accessories are tracked by an external device. The Oculus Rift positional tracking ([[Constellation]]) is achieved by placing an optical sensor pointed at the headset, with the PlayStation VR having a similar setup. In the case of the HTC Vive, tracking is achieved with the [[Lighthouse]] sensors that are placed around the area to be tracked. While this kind of setup is mainly applied to higher-end VR systems, there have been some experiments with outside-in tracking applied to mobile VR. <ref name=”6”> Langley, H. (2017). Inside-out v Outside-in: How VR tracking works, and how it's going to change. Retrieved from https://www.wareable.com/vr/inside-out-vs-outside-in-vr-tracking-343</ref>

The outside-in tracking system needs room calibration after the cameras or sensors are placed, and the data acquired by the system is processed on a computer. <ref name=”3”></ref> <ref name=”5”></ref> Besides its application in VR, this type of tracking is used in motion capturing, as in the case of the film industry. <ref name=”2”></ref>

Outside-in tracking functions as the inverse of [[inside-out tracking]] (Figure 2). While the former places the sensors in a stationary location to track the VR goggle, in the latter the sensors are placed on the goggles and the markers in stationary locations. <ref name=”3”></ref> <ref name=”7”> Ishii, K. (2010). Augmented Reality: Fundamentals and nuclear related applications. Nuclear Safety and Simulation, 1(1)</ref>

==Pros and Cons of outside-in tracking==
At the moment, outside-in tracking has the best accuracy, with the possibility of adding more sensor trackers in the room to further increase it. The latency is also better with this type of tracking, reducing the probability of the user feeling nauseous. Nevertheless, outside-in systems do have limitations, mainly due to occlusion. This occurs when the cameras or sensors cannot track the object because it is out of their line of sight, which leads to tracking errors. <ref name=”6”></ref> <ref name=”8”> Welch,G. and Foxlin, E. (2002). Motion tracking: No silver bullet, but a respectable arsenal. IEEE Computer Graphics and Applications</ref>

==Future of outside-in tracking==
Outside-in tracking is expected to continue to be the main tracking technology in high-end VR systems as the best all-around solution. This market is likely to be the last to move towards the inside-out tracking technology. Other technologies like [[redirected walking]] could also have a great impact in VR positional tracking, further improving the characteristics of outside-in tracking. <ref name=”6”></ref>

==Devices using outside-in tracking==

'''[[Oculus Rift]]''' (including [[Oculus Rift DK2|development kit]])

'''[[PlayStation VR]]'''

==Tracking systems using outside-in tracking==

'''[[Constellation]]'''

'''[[PlayStation Camera]]'''

'''[[Neon Tracking System]]''' (used by [[HTC Link]]<ref>[http://www.roadtovr.com/htc-link-headset-ximmerse-neon-tracking-details/]]</ref>)

[[Category:Terms]] [[Category:Technical Terms]]

==References==

Inside-out tracking

2017-07-19T13:14:03Z

Chelnov:

{{stub}}
{{see also|Marker-less, Inside-Out Tracking‎|Positional tracking}}
[[File:Inside out vs. outside in tracking.png|thumb|Figure 1. Inside-out vs. outside-in tracking (Image: Ishii, 2010)]]
[[File:F2Ak4iE.jpg|thumbnail|Figure 2. Early [[Lighthouse]] prototype, an inside-out tracking system with QR codes as [[fiducial markers]].]]
[[File:Acer mixed reality headset inside-out.png|thumb|Figure 3. Inside-out tracking HMD (image: www.wareable.com)]]

==Introduction==
Inside-out tracking is a method of [[positional tracking]] commonly used in [[virtual reality]] (VR) technologies, specifically for tracking the position of [[head-mounted display|head-mounted displays]] (HMDs) and motion controller accessories. It differentiates itself from [[outside-in tracking]] by the location of the cameras or other sensors that are used to determine the object’s position in space (Figure 1). In inside-out positional tracking, the camera or sensors are located on the device being tracked (e.g. HMD) while in outside-out the sensors are placed in a stationary location. <ref name=”1”> Ribo, M., Pinz, A. and Fuhrmann, A.L. (2001). A new optical tracking system for virtual and augmented reality applications. Instrumentation and Measurement Technology Conference Proceedings</ref> <ref name=”2”> Boger, Y. (2014). Positional tracking: "Outside-in" vs. "Inside-out.” Retrieved from http://vrguy.blogspot.pt/2014/08/positional-tracking-outside-in-vs.html</ref> <ref name=”3”> Ishii, K. (2010). Augmented Reality: Fundamentals and nuclear related applications. Nuclear Safety and Simulation, 1(1)</ref>

A VR device using inside-out tracking looks out to determine how its position changes in relation to the environment. When the headset moves, the sensors readjusts its place in the room and the virtual environment responds accordingly in real time. This type of positional tracking can be achieved with or without markers placed in the environment. The latter is called [[markerless inside-out tracking]]. <ref name=”4”> Langley, H. (2017). Inside-out v Outside-in: How VR tracking works, and how it's going to change. Retrieved from https://www.wareable.com/vr/inside-out-vs-outside-in-vr-tracking-343</ref>

The cameras (or any other optical sensors) that are placed on the HMD observe features of the surrounding environment. When using markers, these are designed to be easily detected by the tracking system and placed in a specific area. These [[fiducial markers]] include primitive shapes like points, squares, and circles (Figure 2). QR codes are an example of positional markers that can be placed in the outside world to serve as reference points for the tracking camera. Inside-out positional tracking can also be achieved using infra-red (IR) markers and a camera that is sensitive to this type of light. In case of using markers, the inside-out system works only as long as it can detect the markers. If these are out of its field of view, positional tracking will be affected. <ref name=”2”></ref> <ref name=”3”></ref> <ref name=”5”> Mehling, M. (2006). Implementation of a Low Cost Marker Based Infrared Optical Tracking System. PhD thesis, Fachhochschule Stuttgart</ref>

With markerless inside-out tracking - a method based on natural features - uses distinctive characteristics that originally exist in the environment to determine position and orientation. The system’s algorithms identify specific images or shapes and uses them to calculate the device’s position in space. Data from accelerometers and gyroscopes can also be used to increase the precision of positional tracking. <ref name=”3”></ref> <ref name=”6”> Boger, Y. (2014). Overview of positional tracking technologies for virtual reality. Retrieved from http://www.roadtovr.com/overview-of-positional-tracking-technologies-virtual-reality/</ref>

==Devices using inside-out tracking==
* ''See also: [[Markerless, inside-out tracking#Markerless inside-out tracking Devices|Devices using markerless inside-out tracking]]''

'''[[HTC Vive]] (including [[HTC Vive Developer Editions|developer editions]])'''

'''Nintendo Wii Remote (not officially used for VR)'''

==Inside-out tracking systems==
* ''See also: [[Markerless, inside-out tracking#Markerless, inside-out tracking Systems|Systems using markerless inside-out tracking]]''

'''[[Lighthouse]] - [[SteamVR]]'''

[[Category:Terms]] [[Category:Technical Terms]]

==References==

Inside-out tracking

2017-07-19T13:07:30Z

Chelnov: /* Devices using inside-out tracking */ Re-ordered list.

{{stub}}
{{see also|Marker-less, Inside-Out Tracking‎|Positional tracking}}
[[File:Inside out vs. outside in tracking.png|thumb|Figure 1. Inside-out vs. outside-in tracking (Image: Ishii, 2010)]]
[[File:F2Ak4iE.jpg|thumbnail|Figure 2. Early [[Lighthouse]] prototype, an inside-out tracking system with QR codes as [[fiducial markers]].]]
[[File:Acer mixed reality headset inside-out.png|thumb|Figure 3. Inside-out tracking HMD (image: www.wareable.com)]]

==Introduction==
Inside-out tracking is a method of [[positional tracking]] commonly used in [[virtual reality]] (VR) technologies, specifically for tracking the position of [[head-mounted display|head-mounted displays]] (HMDs) and motion controller accessories. It differentiates itself from [[outside-in tracking]] by the location of the cameras or other sensors that are used to determine the object’s position in space (Figure 1). In inside-out positional tracking, the camera or sensors are located on the device being tracked (e.g. HMD) while in outside-out the sensors are placed in a stationary location. <ref name=”1”> Ribo, M., Pinz, A. and Fuhrmann, A.L. (2001). A new optical tracking system for virtual and augmented reality applications. Instrumentation and Measurement Technology Conference Proceedings</ref> <ref name=”2”> Boger, Y. (2014). Positional tracking: "Outside-in" vs. "Inside-out.” Retrieved from http://vrguy.blogspot.pt/2014/08/positional-tracking-outside-in-vs.html</ref> <ref name=”3”> Ishii, K. (2010). Augmented Reality: Fundamentals and nuclear related applications. Nuclear Safety and Simulation, 1(1)</ref>

A VR device using inside-out tracking looks out to determine how its position changes in relation to the environment. When the headset moves, the sensors readjusts its place in the room and the virtual environment responds accordingly in real time. This type of positional tracking can be achieved with or without markers placed in the environment. The latter is called [[markerless inside-out tracking]]. <ref name=”4”> Langley, H. (2017). Inside-out v Outside-in: How VR tracking works, and how it's going to change. Retrieved from https://www.wareable.com/vr/inside-out-vs-outside-in-vr-tracking-343</ref>

The cameras (or any other optical sensors) that are placed on the HMD observe features of the surrounding environment. When using markers, these are designed to be easily detected by the tracking system and placed in a specific area. These [[fiducial markers]] include primitive shapes like points, squares, and circles (Figure 2). QR codes are an example of positional markers that can be placed in the outside world to serve as reference points for the tracking camera. Inside-out positional tracking can also be achieved using infra-red (IR) markers and a camera that is sensitive to this type of light. In case of using markers, the inside-out system works only as long as it can detect the markers. If these are out of its field of view, positional tracking will be affected. <ref name=”2”></ref> <ref name=”3”></ref> <ref name=”5”> Mehling, M. (2006). Implementation of a Low Cost Marker Based Infrared Optical Tracking System. PhD thesis, Fachhochschule Stuttgart</ref>

With markerless inside-out tracking - a method based on natural features - uses distinctive characteristics that originally exist in the environment to determine position and orientation. The system’s algorithms identify specific images or shapes and uses them to calculate the device’s position in space. Data from accelerometers and gyroscopes can also be used to increase the precision of positional tracking. <ref name=”3”></ref> <ref name=”6”> Boger, Y. (2014). Overview of positional tracking technologies for virtual reality. Retrieved from http://www.roadtovr.com/overview-of-positional-tracking-technologies-virtual-reality/</ref>

==Devices using inside-out tracking==

[[HTC Vive]] (including [[HTC Vive Developer Editions|developer editions]])

Nintendo Wii Remote (not officially used for VR)

'''[[Markerless, inside-out tracking#Markerless, inside-out tracking Devices|See Devices using markerless, inside-out tracking]]'''

==Inside-out tracking systems==
[[Lighthouse]] - [[SteamVR]]

'''[[Markerless, inside-out tracking#Markerless, inside-out tracking Systems|See Systems using markerless, inside-out tracking]]'''

[[Category:Terms]] [[Category:Technical Terms]]

==References==

Comparison of tracking systems

2017-07-19T12:43:21Z

Chelnov: Started table.

There are several consumer-level tracking systems currently available. Originally, these were used for interaction with regular non-VR video games, but more recent tracking systems have been used for VR systems.

{| class="wikitable"
! style="font-weight: bold;" | Brand & Model
! style="font-weight: bold;" | Inside-out
! style="font-weight: bold;" | Outside-in
! style="font-weight: bold;" | Marker-based
! style="font-weight: bold;" | Marker light frequency
! style="font-weight: bold;" | IMU
! style="font-weight: bold;" | Spacial resolution (mm)
! style="font-weight: bold;" | Latency (ms)
|-
| Facebook/Oculus Rift
| No
| Yes
| Yes
| Infrared
| Yes
| ?
| ?
|-
| HTC Vive
| Yes
| No
| Yes
| Infrared
| Yes
| 0.3
| 15
|-
| Microsoft HoloLens
| Yes
| No
| No
| Infrared
| Yes
| ?
| ?
|-
| Nintendo Wii Remote
| Yes
| No
| Yes
| Infrared
| Yes
| ?
| ?
|-
| Sony PSVR
| No
| Yes
| Yes
| Red/Green/Blue
| Yes
| ?
| 18
|}

Inside-out tracking

2017-07-19T11:04:20Z

Chelnov: Transferred markerless-specific information to the "Markerless inside-out tracking" article.

{{stub}}
{{see also|Marker-less, Inside-Out Tracking‎|Positional tracking}}
[[File:Inside out vs. outside in tracking.png|thumb|Figure 1. Inside-out vs. outside-in tracking (Image: Ishii, 2010)]]
[[File:F2Ak4iE.jpg|thumbnail|Figure 2. Early [[Lighthouse]] prototype, an inside-out tracking system with QR codes as [[fiducial markers]].]]
[[File:Acer mixed reality headset inside-out.png|thumb|Figure 3. Inside-out tracking HMD (image: www.wareable.com)]]

==Introduction==
Inside-out tracking is a method of [[positional tracking]] commonly used in [[virtual reality]] (VR) technologies, specifically for tracking the position of [[head-mounted display|head-mounted displays]] (HMDs) and motion controller accessories. It differentiates itself from [[outside-in tracking]] by the location of the cameras or other sensors that are used to determine the object’s position in space (Figure 1). In inside-out positional tracking, the camera or sensors are located on the device being tracked (e.g. HMD) while in outside-out the sensors are placed in a stationary location. <ref name=”1”> Ribo, M., Pinz, A. and Fuhrmann, A.L. (2001). A new optical tracking system for virtual and augmented reality applications. Instrumentation and Measurement Technology Conference Proceedings</ref> <ref name=”2”> Boger, Y. (2014). Positional tracking: "Outside-in" vs. "Inside-out.” Retrieved from http://vrguy.blogspot.pt/2014/08/positional-tracking-outside-in-vs.html</ref> <ref name=”3”> Ishii, K. (2010). Augmented Reality: Fundamentals and nuclear related applications. Nuclear Safety and Simulation, 1(1)</ref>

A VR device using inside-out tracking looks out to determine how its position changes in relation to the environment. When the headset moves, the sensors readjusts its place in the room and the virtual environment responds accordingly in real time. This type of positional tracking can be achieved with or without markers placed in the environment. The latter is called [[markerless inside-out tracking]]. <ref name=”4”> Langley, H. (2017). Inside-out v Outside-in: How VR tracking works, and how it's going to change. Retrieved from https://www.wareable.com/vr/inside-out-vs-outside-in-vr-tracking-343</ref>

The cameras (or any other optical sensors) that are placed on the HMD observe features of the surrounding environment. When using markers, these are designed to be easily detected by the tracking system and placed in a specific area. These [[fiducial markers]] include primitive shapes like points, squares, and circles (Figure 2). QR codes are an example of positional markers that can be placed in the outside world to serve as reference points for the tracking camera. Inside-out positional tracking can also be achieved using infra-red (IR) markers and a camera that is sensitive to this type of light. In case of using markers, the inside-out system works only as long as it can detect the markers. If these are out of its field of view, positional tracking will be affected. <ref name=”2”></ref> <ref name=”3”></ref> <ref name=”5”> Mehling, M. (2006). Implementation of a Low Cost Marker Based Infrared Optical Tracking System. PhD thesis, Fachhochschule Stuttgart</ref>

With markerless inside-out tracking - a method based on natural features - uses distinctive characteristics that originally exist in the environment to determine position and orientation. The system’s algorithms identify specific images or shapes and uses them to calculate the device’s position in space. Data from accelerometers and gyroscopes can also be used to increase the precision of positional tracking. <ref name=”3”></ref> <ref name=”6”> Boger, Y. (2014). Overview of positional tracking technologies for virtual reality. Retrieved from http://www.roadtovr.com/overview-of-positional-tracking-technologies-virtual-reality/</ref>

==Devices using inside-out tracking==

Nintendo Wii Remote (not officially used for VR)

[[HTC Vive Developer Editions]]

[[HTC Vive CV1]]

'''[[Markerless, inside-out tracking#Markerless, inside-out tracking Devices|See Devices using markerless, inside-out tracking]]'''

==Inside-out tracking systems==
[[Lighthouse]] - [[SteamVR]]

'''[[Markerless, inside-out tracking#Markerless, inside-out tracking Systems|See Systems using markerless, inside-out tracking]]'''

[[Category:Terms]] [[Category:Technical Terms]]

==References==

Markerless inside-out tracking

2017-07-19T11:03:22Z

Chelnov: Transferred markerless-specific information from the "Inside-out tracking

==Introduction==
[[File:Intel Project Alloy.jpg|thumb|Figure 1. Intel's Project Alloy (Image: gizmodo.com)]]

[[Positional tracking]] is an essential component of both [[virtual reality]] (VR) and [[augmented reality]] (AR), contributing to a greater sense of [[immersion]] and [[presence]]. It determines the position and orientation of an object within the environment. In VR, this allows for the movements of the user to be translated into the virtual environment, and in AR it is essential for the placement of digital content into real objects or spaces. Markerless inside-out tracking is a composite term that defines a form of positional tracking that uses two specific methods: [[markerless tracking]] and [[inside-out tracking]]. <ref name=”1”> Boger, Y. (2014). Overview of positional tracking technologies for virtual reality. Retrieved from http://www.roadtovr.com/overview-of-positional-tracking-technologies-virtual-reality/</ref> <ref name=”2”> Ziegler, E. (2010). Real-time markerless tracking of objects on mobile devices. Bachelor Thesis, University of Koblenz and Landau</ref>

Markerless tracking is a method of motion tracking that avoids the use of markers (also known as [[fiducial markers]]). These markers are usually placed in the environment or in the head-mounted displays (HMDs), helping the system determine the users or camera position. The Markerless method uses instead natural features already present in the environment, for tracking purposes. <ref name=”3”> Virtual Reality Society. Virtual reality motion tracking technology has all the moves. Retrieved from https://www.vrs.org.uk/virtual-reality-gear/motion-tracking</ref> <ref name=”4”> Klein, G. (2006). Visual tracking for augmented reality. Ph.D. thesis, University of Cambridge, Department of Engineering</ref> This method is considered more flexible and effective since there isn’t the need for a prepared environment with markers. <ref name=”5”> Zikas, P., Bachlitzanakis, V., Papaefthymiou, M. and Papagiannakis, G. (2016). A mobile, AR inside-out positional tracking algorithm, (MARIOPOT), suitable for modern, affordable cardboard-style VR HMDs. In Digital Heritage. Progress in cultural heritage: documentation, preservation, and protection. Springer International Publishing, Switzerland</ref> <ref name=”6”> Lima, J.P., Roberto, R., Simões, F., Almeida, M., Figueiredo, L., Teixeira, J.M. and Teichrieb, V. (2017). Markerless tracking system for augmented reality in the automotive industry. Expert Systems With Applications, 82: 100-114</ref> The decreasing cost of computer vision is another factor that has made markerless tracking an attractive alternative of tracking. However, this method still has some problems, such as motion blur and fast motion affecting tracking. <ref name=”7”> Fang, W., Zheng, L., Deng, H. and Zhang, H. (2017). Real-time motion tracking for mobile augmented/virtual reality using adaptive visual-inertial fusion. Sensors, 17</ref> It also demands a trade-off between precision and efficiency. <ref name=”2”></ref>

Inside-out is a term that defines the position of the cameras or other sensors relative to the object to be tracked. If they are placed in a stationary location exterior to the HMD, for example, it is considered [[outside-in tracking]]. In inside-out, the camera is placed in the HMD. <ref name=”8”> Boger, Y. (2014). Positional tracking: "Outside-in" vs. "Inside-out." Retrieved from https://vrguy.blogspot.pt/2014/08/positional-tracking-outside-in-vs.html</ref> There is great interest in inside-out tracking since it simplifies the setup and allows the user a greater sense of freedom by not being limited to a specific tracking space. Inside-out positional tracking has the potential to make VR completely wireless, more convenient and accessible. Some have gone as far as saying that it was the “holy grail” of the VR scene. <ref name=”9”> Robertson, A. (2017). Self-tracking headsets are 2017’s big VR trend — but they might leave your head spinning. Retrieved from https://www.theverge.com/2017/1/12/14223416/vr-headset-inside-out-tracking-intel-qualcomm-microsoft-ces-2017</ref> <ref name=”10”> Durbin, J. (2016). Google: Wireless positional tracking “solved”, but heat still a problem for VR. Retrieved from https://uploadvr.com/inside-out-google-solve-tracking/</ref>.

With inside-out, the data that is gathered is generally processed by the headset, giving the user an increased mobility within a room. It can also be the case that the sensors are connected to a computer that is carried by the user or the signal is sent wirelessly to a stationary processing unit, but since inside-out tracking aims to provide more freedom of use the optimal solution is the headset providing all the computational power. <ref name=”2”></ref>

There is a great deal of interest in markerless technology. While marker-based systems are still better for accuracy and latency, there has been big investments in researching and developing markerless tracking for it to become the leading positional tracking technology. Indeed, it became the big VR trend of 2017, with the potential to make VR more convenient and accessible. <ref name=”4”></ref> <ref name=”7”> Robertson, A. (2017). Self-tracking headsets are 2017’s big VR trend — but they might leave your head spinning. Retrieved from https://www.theverge.com/2017/1/12/14223416/vr-headset-inside-out-tracking-intel-qualcomm-microsoft-ces-2017</ref>

High-end VR headsets use external cameras or external markers to calculate the user’s position in space and translate it to the virtual environment, and mobile VR systems have no positional tracking. Markerless technology could not only simplify the setup for high-end headsets but also expand the capabilities of mobile VR. <ref name=”7”></ref>

Companies are starting to offer interesting inside-out systems. Microsoft has been investing in this technology for a while, with the [[HoloLens]] and, more recently, with the new line of mixed reality headsets which includes the [[Acer Windows Mixed Reality Headset]] (Figure 3). [[Oculus]] has announced a markerless prototype called Santa Cruz, and Qualcomm’s 835 reference headset is designed to help other manufacturers build their own systems. Intel has also shown a version of its Project Alloy - a “merged reality” HMD that uses markerless tracking. Finally, Google has presented a markerless system named WorldSense intended for use with the VR headsets for the Daydream platform. <ref name=”4”></ref> <ref name=”7”></ref> <ref name=”8”> Lang, B. (2017). Google announces ‘WorldSense’ inside-out tracking for standalone daydream VR headsets. Retrieved from http://www.roadtovr.com/google-announces-worldsense-inside-tracking-standalone-daydream-vr-headsets/</ref>

==Advantages of markerless inside-out tracking==
The benefits of using markerless inside-out are those that come from the individual advantages of each tracking method.

The main advantage of markerless systems is the freedom - the increased mobility - they give to the users. While marker-based systems provide great accuracy, they need external sensors. With markerless, the computer can calculate the headset’s position based on signals like depth and acceleration, without a fixed point of reference. Another advantage is that markerless systems may not suffer from occlusion. This occurs in marker-based tracking, when the user gets out of the field of view of the external cameras. On the other hand, having a device that can determine orientation and position independently of external cameras or sensors provides a deeper sense of immersion. Finally, markerless technology is essential for augmented and mixed reality since these technologies demand more mobility from the systems. <ref name=”3”></ref> <ref name=”4”></ref> <ref name=”7”></ref>

Currently, markerless tracking systems still lack in accuracy and latency, although improvements are constantly made. It requires good computer vision, that is a bit further behind outside-in solutions. Another disadvantage, related to inside-out tracking rather than the markerless aspect, is that all the computational work must be done by the HMD. <ref name=”4”></ref>

===Markerless===
* Can work within unprepared environment;
* No special hardware required;
* No fiducial markers;
* Able to use natural features to calculate position and orientation. <ref name=”5”></ref> <ref name=”7”></ref> <ref name=”11”> Hsia, J.S. (2017). Markerless AR: 4 Things developers need to know. Retrieved from https://developer.att.com/blog/markerless-ar-developers</ref>
* Increased mobility and freedom;
* Not affected by occlusion;
* Provides a deeper sense of immersion since the user is not tethered. <ref name=”9”></ref> <ref name=”12”> Langley, H. (2017). Inside-out v Outside-in: How VR tracking works, and how it's going to change. Retrieved from https://www.wareable.com/vr/inside-out-vs-outside-in-vr-tracking-343</ref>

===Inside-out===
* No need for external sensors and cables, but rather requires only a light-emitter;

==Project Tango and Project Alloy, Future of inside-out tracking==

[[Tango]] is a [[Google]]’s project that allows smartphones and other mobile devices to understand their location in space. It is a software and hardware solution that offers inside-out technology and markerless tracking. According to Google Tango’s director of engineering, Johnny Lee, “As you can see [inside-out positional tracking] clearly works on this phone…We’ve even had people strap a tablet sized device with Tango built in into a custom VR headset and the positional tracking worked just as well as it does here…The only thing really holding us back right now are the thermals. Right now, phones just get way too hot if we ask them to run positional tracking and split-screen stereoscopic image at 90 fps…As Daydream matures and Tango continues to improve, the sophistication around tracking will also evolve over the next 2-3 years.“ <ref name=”10”></ref>

In 2016, Intel announced [[Project Alloy]] (Figure 1) - a VR system. It is also a markerless inside-out tracking device. During CES 2017, Intel showed off a developer kit of the project. Project Alloy uses a tiny camera array called Intel RealSense. These cameras are able to make a 3D map of the environment (e.g. a room) and the objects in it. The headset does not need wires, and it is powered by a battery. <ref name=”13”> Nunez, M. (2017). Intel’s Project Alloy is what a VR system should be. Retrieved from http://gizmodo.com/intels-project-alloy-is-what-a-vr-system-should-be-1790818104</ref>

An inside-out system with perfect accuracy is considered the holy grail of positional tracking. While it is expected that the technology will evolve considerably in the future, outside-in will continue to exist as the best solution for high-end VR systems. This specific market will probably be the last to adopt inside-out tracking. The implementation of augmented reality systems will also likely drive the use of inside-out since those systems require great mobility. According to Youssri Helmy, CEO of Eonite, when referring to inside-out said that “It’s got to happen. We think it's crucial. It's like the invention of the mouse with the GUI.” <ref name=”4”></ref> <ref name=”7”></ref>

==Markerless, inside-out tracking Devices==
[[Meta 2]]

[[Microsoft HoloLens]]

==Markerless, inside-out tracking Systems==
[[Oculus Santa Cruz]] - [[Oculus VR]]

[[Project Alloy]] - [[Intel]]

[[Snapdragon VR]] - [[Qualcomm]]

[[Tango]] - [[Google]]

[[Windows MR Tracking]] - [[Microsoft]]

[[WorldSense]] - [[Google]] - inside-out tracking system for standalone [[Daydream]] headsets

==References==
<references/>

[[Category:Terms]] [[Category:Technical Terms]]

Markerless outside-in tracking

2017-07-19T10:37:51Z

Chelnov: Added very basic description.

{{stub}}
{{see also|Positional tracking}}

==Introduction==

[[Positional tracking]] is an essential component of both [[virtual reality]] (VR) and [[augmented reality]] (AR), contributing to a greater sense of [[immersion]] and [[presence]]. It determines the position and orientation of an object within the environment. In VR, this allows for the movements of the user to be translated into the virtual environment, and in AR it is essential for the placement of digital content into real objects or spaces. Markerless outside-in tracking is a composite term that defines a form of positional tracking that uses two specific methods: [[markerless tracking]] and [[outside-in tracking]]. <ref name=”1”> Boger, Y. (2014). Overview of positional tracking technologies for virtual reality. Retrieved from http://www.roadtovr.com/overview-of-positional-tracking-technologies-virtual-reality/</ref> <ref name=”2”> Ziegler, E. (2010). Real-time markerless tracking of objects on mobile devices. Bachelor Thesis, University of Koblenz and Landau</ref>

Markerless tracking is a method of motion tracking that avoids the use of markers (also known as [[fiducial markers]]). These markers are usually placed in the environment or in the head-mounted displays (HMDs), helping the system determine the users or camera position. The Markerless method uses instead natural features already present in the environment, for tracking purposes. <ref name=”3”> Virtual Reality Society. Virtual reality motion tracking technology has all the moves. Retrieved from https://www.vrs.org.uk/virtual-reality-gear/motion-tracking</ref> <ref name=”4”> Klein, G. (2006).

Markerless outside-in tracking is a technology that was used prior to the wide availability of consumer VR devices. Two popular non-VR systems based on this form of tracking are the PlayStation [https://en.wikipedia.org/wiki/EyeToy EyeToy], released in October 2003, and the Xbox [https://en.wikipedia.org/wiki/Kinect Kinect], released in November 2010.

With markerless outside-in tracking, cameras are mounted in the environment, such as on top of a television set, and aimed at the user. The user's movements are tracked without requiring any kind of markers or other hardware. The disadvantage of this system is that lacks the fine spacial accuracy and low-latency of marker-based systems.

Markerless outside-in tracking

2017-07-19T10:25:54Z

Chelnov: Created page