Tracking method and tracking system

A tracking method for tracking a head-mounted device includes following steps. First pose data of the head-mounted device is tracked in an inside-out coordinate system. Second pose data of the head-mounted device is tracked in an outside-in coordinate system. A transformation relationship between the inside-out coordinate system and the outside-in coordinate system is calculated according to the first pose data and the second pose data. The first pose data in the inside-out coordinate system is transformed into third pose data in the outside-in coordinate system according to the transformation relationship. In response to that the second pose data is currently available, the second pose data is utilized to determine a device pose of the head-mounted device. In response to that the second pose data is currently unavailable, the third pose data is utilized to determine the device pose of the head-mounted device.

BACKGROUND

Field of Invention

The disclosure relates to a tracking method and a tracking system. More particularly, the disclosure relates to a tracking method and a tracking system utilized on a head-mounted device.

Description of Related Art

Virtual Reality (VR), Augmented Reality (AR), Substitutional Reality (SR), and/or Mixed Reality (MR) devices are developed to provide immersive experiences to users. When a user wearing a head-mounted device, the visions of the user will be covered by the immersive content shown on the head-mounted device. The immersive content shows a scenario of a specific space.

To supply the immersive experiences, it is necessary to track a movement of the user, and to provide a screen to user's vision corresponding to the movement in real-time. When the user moves to different positions, a scene in the virtual reality should change to a different point of view simultaneously. Therefore, in applications of VR, AR or MR, it is important to provide an effective and precise way to track user's movement.

SUMMARY

The disclosure provides a tracking method, which includes following steps. First pose data of a head-mounted device is tracked in an inside-out coordinate system. Second pose data of the head-mounted device is tracked in an outside-in coordinate system. A transformation relationship between the inside-out coordinate system and the outside-in coordinate system is calculated according to the first pose data and the second pose data. The first pose data in the inside-out coordinate system is transformed into third pose data in the outside-in coordinate system according to the transformation relationship. In response to that the second pose data is currently available, the second pose data is utilized to determine a device pose of the head-mounted device. In response to that the second pose data is currently unavailable, the third pose data is utilized to determine the device pose of the head-mounted device.

The disclosure provides a tracking system, which include a head-mounted device, a tracking station and a processing unit. The head-mounted device is configured to track first pose data of the head-mounted device in an inside-out coordinate system. The tracking station is interacted with the head-mounted device for tracking second pose data of the head-mounted device in an outside-in coordinate system. The processing unit is configured to receive the first pose data and the second pose data. The processing unit is configured to calculate a transformation relationship between the inside-out coordinate system and the outside-in coordinate system according to the first pose data and the second pose data. The processing unit is configured to transform the first pose data in the inside-out coordinate system into third pose data in the outside-in coordinate system according to the transformation relationship. In response to that the second pose data is currently available, the second pose data is utilized by the processing unit to determine a device pose of the head-mounted device. In response to that the second pose data is currently unavailable, the third pose data is utilized by the processing unit to determine the device pose of the head-mounted device.

The tracking system and the tracking method are able to track the head-mounted device with two kinds of tracking functions including the inside-out tracking function and the outside-in tracking function, such that the head-mounted device can be tracked with a relatively higher preciseness and a shorter latency with a relatively lower power consumption. When the outside-in tracking function loses its tracking due to some limitations, the inside-out tracking function can seamless provide the pose data of the head-mounted device.

DETAILED DESCRIPTION

Reference is made toFIG. 1, which is a schematic diagram illustrating a tracking system100according to an embodiment of this disclosure. The tracking system100includes a head-mounted device120and a tracking station140located in a spatial area SA. For example, the spatial area SA as shown inFIG. 1can be a bedroom or a conference room in the real world, but the disclosure is not limited thereto. In some other embodiments, the spatial area SA can also be a specific area at an outdoor space (not shown in figures).

The head-mounted device120is mounted on the head of a user in the spatial area SA. The disclosure is not limited to one head-mounted device as shown inFIG. 1. The tracking system100is able to track two or more head-mounted devices. The user may move to different positions and face toward various directions in the spatial area SA. In the case, the head-mounted device120can be moved to different positions (based on the movement of the user) and have different orientations (based on the orientation of the user's head).

Different technologies have been developed to track the movement of the user. There are two main categories of tracking technologies, which are inside-out tracking and outside-in tracking. The inside-out tracking is to track the movement in view of the head-mounted device itself relative to an outside environment. The outside-in tracking is to track the movement in view of an external device, which is disposed separately from the head-mounted device and configured to observe/track the movement of the head-mounted device.

In some embodiments, the head-mounted device120can provide Virtual Reality (VR), an Augmented Reality (AR), a Substitutional Reality (SR), or a Mixed Reality (MR) contents to the user. In order to provide an immersive experience to the users, the tracking system100is configured to track the head-mounted device120so as to detect a position and a rotation of user's movement.

In some embodiments, the head-mounted device120is able to track a device pose of itself by an inside-out tracking function, which is capable of observing some objects (e.g., feature anchors AN1and AN2) in the spatial area SA from an inside point of view (i.e., from the view of the head-mounted device120) so as to detect an inside-out pose data about the head-mounted device120.

In some embodiments, the tracking station140is disposed at a fixed position within the spatial area SA. For example, the tracking station140is disposed at a corner near a ceiling of the room shown inFIG. 1. In some embodiments, the tracking station140is a component for providing an outside-in tracking function, which is capable of tracking the head-mounted device120from an outside point of view so as to detect an outside-in pose data about the head-mounted device120.

In some embodiments, the tracking system100includes a processing unit160. The processing unit160is able to receive both of the inside-out pose data and the outside-in pose data, and the processing unit160utilizes a combination of the inside-out pose data and the outside-in pose data to determine a device pose of the head-mounted device120. In other words, the tracking system100is able to integrate two kinds of tracking functions (e.g., inside-out and outside-in) for tracking the head-mounted device120. Further details will be discussed in following paragraphs.

In some embodiments, the processing unit160can be a processor in a computer separated from the head-mounted device120and the tracking station140. In some other embodiments, the processing unit160can be implemented by a processor or an application specific integrated circuit (ASIC) integrated in the head-mounted device120or the tracking station140.

Reference is further made toFIG. 2, which is a functional diagram illustrating the tracking system100according to some embodiments of the disclosure.

In some embodiments, as shown inFIG. 1andFIG. 2, the head-mounted device120includes a camera122, optical sensors124and an inertial measurement unit (IMU)126. In some embodiments, the camera122and the inertial measurement unit126are configured to achieve the inside-out tracking function TR1.

As the embodiment shown inFIG. 1, the camera122is disposed on a front side of the head-mounted device120, and the camera122is configured to capture a streaming image data in view of the head-mounted device120.

Based on the streaming image data captured by the camera122, the tracking system100is able to find at least one feature anchor (e.g., the feature anchors AN1and AN2) in the spatial area SA. As the embodiment shown inFIG. 1, the feature anchor AN1can be a window of the room, and the feature anchor AN2can be a television in the room. Based on the streaming image data, the head-mounted device120(or the processing unit160) is able to construct a map of the spatial area SA and sense relative locations of the head-mounted devices120relative to the feature anchors AN1and AN2in the spatial area SA. In some embodiments, Simultaneous Localization and Mapping (SLAM) technology is utilized by the head-mounted device120(or the processing unit160) to construct the map of an unknown environment (e.g., the spatial area SA) while simultaneously tracking the head-mounted device120within the unknown environment.

Based on a size and/or a sharp of the feature anchors AN1and AN2appeared in the streaming image data observed by the camera122, the inside-out tracking function TR1can detect a distance between the head-mounted device120and the feature anchor AN1and another distance between the head-mounted device120and the feature anchor AN2, such that the inside-out tracking function TR1can detect the position of the head-mounted device120. In some other embodiments, the head-mounted device120can include two or more cameras (not shown in figures) for performing the inside-out tracking function TR1with a higher preciseness. The inertial measurement unit126is able to detect an orientation or a rotation of the head-mounted device120. As shown inFIG. 2, the inside-out tracking function TR1is able to track first pose data PD1of the head-mounted device120in an inside-out coordinate system. The first pose data PD1is about the position and the orientation of the head-mounted device120in the inside-out coordinate system. The head-mounted device120is movable within a spatial area SA. The first pose data PD1is tracked in view of the head-mounted device120relative to the spatial area SA.

It is noticed that, in embodiments shown inFIG. 2, the inside-out tracking function TR1is implemented by the computer vision tracking manner including the camera122and the inertial measurement unit126, but the disclosure is not limited thereto. In some other embodiments, the inside-out tracking function TR1can be implemented by other equivalent tracking technologies, such as an ultrasound tracking (e.g., casting an outward ultrasound and detecting a returned ultrasound), an infrared tracking or any similar inside-out tracking manner.

In some embodiments, as shown inFIG. 1andFIG. 2, the tracking station140includes an optical emitter142. The head-mounted device120includes several optical sensors124. In some embodiments, the optical emitter142and the optical sensors124are configured to achieve an outside-in tracking function TR2. In some embodiments, the optical sensors124are disposed at different spots on the head-mounted device120. The optical sensors124are configured to respectively detect an optical signal generated by the optical emitter142for tracking second pose data PD2about the head-mounted device120in an outside-in coordinate system. Because the optical sensors124are disposed at different spots on the head-mounted device120, the optical signal casted from the optical emitter142will reach each of the optical sensors124at slightly different timings. According to the time differences, the outside-in tracking function TR2is able to track the second pose data PD2about the head-mounted device120. In this embodiment, the second pose data PD2can be generated by the optical sensors124.

The second pose data PD2is about a position and an orientation of the head-mounted device120in the outside-in coordinate system. The second pose data PD2is tracked in view of the tracking station140. The tracking station140is disposed at a fixed position within the spatial area SA.

It is noticed that, in embodiments shown inFIG. 2, the outside-in tracking function TR2is implemented by the optical tracking manner including the optical sensors124and the optical emitter142, but the disclosure is not limited thereto. For example, alternatively, the optical emitter (not shown in figures) can be disposed on the head-mounted device120and the optical sensors can be disposed on the tracking device. In some other embodiments, the tracking device140can use a computer vision (a camera and corresponding object recognition) to perform the outside-in tracking function TR2. In some other embodiments, the tracking station140can use an ultrasound tracking, an infrared tracking or any equivalent outside-in tracking technology to perform the outside-in tracking function TR2.

In most of cases, the outside-in tracking function TR2can provide a higher preciseness, a shorter latency and/or a lower power consumption in tracking the head-mounted device120, compared to the inside-out tracking function TR1. However, the outside-in tracking function TR2has some limitations in some specific cases. For example, the optical emitter142can emit the optical signal to a coverage area CA as shown inFIG. 1. When the user steps outside of the coverage area CA, the outside-in tracking function TR2will lose its tracking about the head-mounted device120. In this case, the user is limited to move within the coverage area CA. In another example, when the user rotates to a specific angle or when the user raise his/her arms over his/her head, the optical signal generated by the optical emitter142might be blocked from the optical sensors124on the head-mounted device120, and the outside-in tracking function TR2will also lose its tracking about the head-mounted device120.

On the other hand, the inside-out tracking function TR1is not limited to the coverage area CA. However, the inside-out tracking function TR1will induce a longer latency, a lower preciseness and/or a higher power consumption (for performing a computer vision computation) in tracking the head-mounted device120, compared to the outside-in tracking function TR2.

In some embodiments, the processing unit160is able to combine the first pose data PD1from the inside-out tracking function TR1and the second pose data PD2from the outside-in coordinate system for determining the device pose PHMD of the head-mounted device120.

Reference is further made toFIG. 3, which is a flowchart illustrating a tracking method200according to some embodiments of the disclosure. The tracking method200can be executed by the tracking system100shown inFIG. 1andFIG. 2.

As shown inFIG. 2andFIG. 3, in step S210, the first pose data PD1of the head-mounted device120in the inside-out coordinate system is tracked by the inside-out tracking function TR1. In step S220, the second pose data PD2of the head-mounted device120in the outside-in coordinate system is tracked by the outside-out tracking function TR2.

It is noticed that, in some embodiments, the inside-out coordinate system is in view of the head-mounted device120, and the outside-in coordinate system is in view of the tracking station140. Therefore, the first pose data PD1and the second pose data PD2cannot be directly compared with each other or directly utilized together to determine the device pose PHMD.

As shown inFIG. 2,FIG. 3, in step S230, the rotation estimator162of the processing unit160calculates a transformation relationship TRAN between the inside-out coordinate system and the outside-in coordinate system according to the first pose data PD1and the second pose data PD2.

The transformation relationship TRAN between the inside-out coordinate system and the outside-in coordinate system can be calculated in some further steps. At first, a rotation estimator162of the processing unit160obtains at least one static pair of the first pose data PD1and the second pose data PD2simultaneously (at the same time). The first pose data PD1records the pose data about the head-mounted device120in view of the inside-out coordinate system, and the second pose data PD2records the pose data about the same head-mounted device120in view of the outside-in coordinate system. The rotation estimator162of the processing unit160can align the first pose data PD1and the second pose data PD2in the static pair, so as to find out an alignment between the first pose data PD1and the second pose data PD2. Afterward, the rotation estimator162of the processing unit160can calculate the transformation relationship TRAN based on the first pose data PD1and the second pose data PD2after alignment. It is noticed that, in some embodiments, several static pairs of the first pose data PD1and the second pose data PD2can be collected at different time spots in a time period. Each of the static pairs includes one first pose data PD1and one second pose data PD2at the same time. For example, one static pair can be collected per second within one minute, such that sixty static pairs of the first pose data PD1and the second pose data PD2are collected for calculating the transformation relationship TRAN.

In some embodiments, the transformation relationship TRAN includes a rotation transformation matrix between the inside-out coordinate system and the outside-in coordinate system and a position transformation matrix between the inside-out coordinate system and the outside-in coordinate system. The transformation relationship TRAN can be calculated as:
OWODPi−OWODP0=OWIWR(IWIDPi−IWIDP0)+OWODR0ODIDP+OWIWRIWIDRi ODIDP(a)
OWIDRi=OWIWRIWIDRi ODIDR(b)

The position transformation matrix of the transformation relationship TRAN can be calculated as formula (a), and the rotation transformation matrix of the transformation relationship TRAN can be calculated as formula (b).

Reference is further made toFIG. 4AandFIG. 4B.FIG. 4Ais a schematic diagram illustrating the inside-out coordinate system and the outside-in coordinate system at a time spot T0in some embodiments.FIG. 4Bis a schematic diagram illustrating the inside-out coordinate system and the outside-in coordinate system at another time spot Ti(after the time spot T0) in some embodiments.

As shown inFIG. 4AandFIG. 4B, there are an outside-in world coordinate system OW, an outside-in driver coordinate system OD, an inside-out world coordinate system IW and an inside-out driver coordinate system ID. Among formulas (a) and (b), P0is a position of the head-mounted device120at time spot T0; Piis a position of the head-mounted device120at the time spot Ti;OWODPi−OWODP0is a displacement DIS of the head-mounted device120from the time spot T0to the time spot Titransforming form the outside-in driver coordinate system OD into the outside-in world coordinate system OW.OWIDRiis a rotation transformation matrix of the head-mounted device120at the time spot Titransforming form the inside-out driver coordinate system ID into the outside-in world coordinate system OW.

The outside-in world coordinate system OW is fixed and the inside-out world coordinate system IW is also fixed. The outside-in world coordinate system OW and the inside-out world coordinate system IW may have different origins and different orientations. The rotation transformation matrixOWIWR between the inside-out world coordinate system IW to the outside-in world coordinate system OW and can be found based on the first pose data PD1and the second pose data PD2after alignment.

The outside-in driver coordinate system OD is decided according to an orientation of the optical emitter142in the tracking station140. The rotation transformation matrixOWODR between the outside-in world coordinate system OW and the outside-in driver coordinate system OD can be detected by the optical emitter142(e.g., by a sensor connected to the optical emitter142) of the tracking station140.

The inside-out driver coordinate system ID is decided according to an orientation of the head-mounted device120. The rotation transformation matrixIWIDR between the inside-out world coordinate system IW and the inside-out driver coordinate system ID can be detected by the inertial measurement unit126and the camera122of the head-mounted device120. Because the rotation transformation matrixODIDR the position transformation matrixIDODP and the rotation transformation matrixIWOWR in aforesaid formulas (a) and (b) can be known through the alignment between the first pose data PD1and the second pose data PD2. Therefore, the transformation relationship TRAN, including the formulas (a) and (b), can be acknowledged.

Based on the transformation relationship TRAN, as shown inFIG. 2andFIG. 3, in step S240, a pose transformer164of the processing unit160is configured to transform the first pose data PD1in the inside-out coordinate system into the third pose data PD3in the outside-in coordinate system.

It is noticed that, the transformation relationship TRAN can be calculated while the first pose data PD1and the second pose data PD2are both available. Afterward, if the user moves outside the coverage area CA or blocks the optical signal from the optical sensors124and the outside-in tracking function TR2currently cannot generate the second pose data PD2(i.e., the second pose data PD2is unavailable), the first pose data PD1generated by the inside-out tracking function TR1can be transformed into the third pose data PD3in the outside-in coordinate system in step S240. In this case, the tracking system100is able to keep tracking the device pose PHMD (in the outside-in coordinate system) even when the second pose data PD2is unavailable.

As shown inFIG. 2andFIG. 3, in step S250, the processing unit160applies a combination of the second pose data PD2and the third pose data PD3to determine the device pose PHMD.

Reference is further made toFIG. 5, which is a flowchart illustrating further details in the step S250of the tracking method200shown inFIG. 3. The tracking method200can be executed by the tracking system100shown inFIG. 1andFIG. 2.

As embodiments shown inFIG. 2andFIG. 5, there are four steps S251˜S254in the step S250. In step S251, the processing unit160detect whether the second pose data PD2is currently available or not. In response to that the second pose data is currently available, step S252is performed, by a pose switcher166in the processing unit160, to select the second pose data PD2as the device pose PHMD of the head-mounted device120.

In response to that the second pose data is currently unavailable (e.g., moving out of the coverage area CA or blocking the optical signal), step S254is performed, by a pose switcher166in the processing unit160, to select the third pose data PD3as the device pose PHMD of the head-mounted device120.

In some embodiments, if the device pose PHMD is switched by the tracking system100from the second pose data PD2into the third pose data PD3immediately (when the second pose data PD2is just lost), the user will feel uncomfortable because the device pose PHMD may change dramatically, and the screen shown on the head-mounted device120may also change dramatically.

Therefore, in some embodiments, the tracking method200further include a step S253before the step S254(selecting the third pose data PD3as the device pose PHMD). In the step S253, when the second pose data PD2is just changed from available to unavailable, the pose switcher166utilizes fusion pose data PDf between a latest available data of the second pose data PD2and the third pose data PD3to determine the device pose PHMD of the head-mounted device120. Reference is further made toFIG. 6A, which is a schematic diagram illustrating a transition between the second pose data PD2and the third pose data PD3in some embodiments. As shown inFIG. 6A, before a time spot T1, the second pose data PD2is available, and the device pose PHMD is equal to the second pose data PD2. Started from the time spot T1, the second pose data PD2is just unavailable; the device pose PHMD is equal to the fusion pose data PDf between a latest available data of the second pose data PD2and the third pose data PD3. At the beginning, a ratio Rpd2of the second pose data PD2is higher in determining the whole device pose PHMD and another ratio Rpd3of the third pose data PD3is lower in determining the device pose PHMD. In other words, at the beginning, the device pose PHMD is mainly affected by the second pose data PD2. Then the ratio Rpd2in determining the whole device pose PHMD gradually decreases, and the ratio Rpd3in determining the device pose PHMD gradually increases. After the time spot T2, the device pose PHMD is equal to the third pose data PD3.

Similarly, when the second pose data PD2resumes from unavailable to available, the fusion pose data PDf can be utilized to gradually increase the ratio Rpd2. As shown inFIG. 5, step S255is performed, by the processing unit160, to detect whether the second pose data PD2resumes from unavailable into available. When the second pose data PD2remains unavailable, it returns to step S254. When the second pose data PD2resumes from unavailable to available, step S256is performed, and the pose switcher166utilizes the fusion pose data PDf to determine the device pose PHMD of the head-mounted device120. Reference is further made toFIG. 6B, which is a schematic diagram illustrating a transition between the third pose data PD3and the second pose data PD2in some embodiments. In this case, the fusion pose data PDf transfers from the third pose data PD3back to the second pose data PD2, as shown inFIG. 6B. Afterward, step S252is performed, and the pose switcher166utilizes the second pose data PD2to determine the device pose PHMD of the head-mounted device120.

As shown inFIG. 1, the user may also hold at least one hand-held controller180. In some embodiments, the hand-held controller180is an input interface of a Virtual Reality (VR), Augmented Reality (AR), Substitutional Reality (SR), and/or Mixed Reality (MR) system, such that the user can interact with virtual objects through the hand-held controller180. It is also required to track the movement of the hand-held controller180by the tracking system100.

Reference is further made toFIG. 7, which is a functional diagram illustrating the tracking system100involving a tracking function for the hand-held controller180according to some embodiments of the disclosure. Compared to embodiments shown inFIG. 2, there is another inside-out tracking function TR3shown inFIG. 7for the hand-held controller180.

As shown inFIG. 7, the inside-out tracking function TR3is implemented by the camera122, the inertial measurement unit126and the hand-held controller180. The camera122is able to capture a streaming image about the hand-held controller180in view of the head-mounted device120, and map a position and a rotation (referring to a signal from the inertial measurement unit126) of the hand-held controller180onto the inside-out coordinate system. The inside-out tracking function TR3is able generate fourth pose data PD4of the hand-held controller180in view of the head-mounted device120in the inside-out coordinate system.

Because the fourth pose data PD4cannot be directly utilized in combination with other pose data in the outside-in coordinate system, the pose transformer164of the processing unit160is further configured to transform the fourth pose data in the inside-out coordinate system into fifth pose data PD5in the outside-in coordinate system according to the transformation relationship TRAN. In this case, the pose switcher166can apply the fifth pose data PD5to determine a controller pose PCON of the hand-held controller180.

In embodiments shown inFIG. 7, the controller pose PCON is decided by the fourth pose data PD4tracked by the inside-out tracking function TR3, but the disclosure is not limited thereto.

Reference is further made toFIG. 8, which is a functional diagram illustrating the tracking system100ainvolving two tracking functions for the hand-held controller180according to some embodiments of the disclosure. Compared to embodiments shown inFIG. 2, there are two additional tracking functions, which are an inside-out tracking function TR3shown inFIG. 8and an outside-in tracking function TR4for the hand-held controller180.

As shown inFIG. 8, the inside-out tracking function TR3is implemented by the camera122, the inertial measurement unit126and the hand-held controller180, and the outside-in tracking function TR4is implemented by the optical emitter142of the tracking station140and the optical sensors182disposed on the hand-held controller180. The inside-out tracking function TR3is able generate fourth pose data PD4of the hand-held controller180in view of the head-mounted device120in the inside-out coordinate system. The pose transformer164of the processing unit160is further configured to transform the fourth pose data PD4in the inside-out coordinate system into fifth pose data PD5in the outside-in coordinate system according to the transformation relationship TRAN. The outside-in tracking function TR4is able generate sixth pose data PD6of the hand-held controller180in view of the tracking station140in the outside-in coordinate system.

In aforesaid embodiments, the transformation relationship TRAN between the inside-out coordinate system and the outside-in coordinate system is calculated according to the first pose data PD1and the second pose data PD2, but the disclosure is not limited thereto. In some embodiments, the fourth pose data PD4in the inside-out coordinate system about the hand-held controller180and the sixth pose data PD6in the outside-in coordinate system about the hand-held controller180can also be transmitted to the rotation estimator162(not shown inFIG. 8). In this case, the rotation estimator162may further utilizes additional static pair(s) between the fourth pose data PD4and the sixth pose data PD6to calculate the transformation relationship TRAN, in addition to the static pair(s) between the first pose data PD1and the second pose data PD2.

Similar to the embodiments shown inFIG. 5, the tracking system100ainFIG. 8can select the fifth pose data PD5or the sixth pose data PD6as the controller pose PCON. Similarly, the tracking system100acan generate fusion pose data between the fifth pose data PD5and the sixth pose data PD6as the controller pose PCON during a transition between the fifth pose data PD5and the sixth pose data PD6. Details about aforesaid selection and transition have been discussed in similar embodiments shown inFIG. 5, and not to be repeated here again.

Based on aforesaid embodiments, the tracking system100or100aand the tracking method200are able to track the head-mounted device120and the hand-held controller180with two kinds of tracking functions including the inside-out tracking functions (TR1, TR3) and the outside-in tracking functions (TR2, TR4), such that the head-mounted device120and the hand-held controller180can be tracked with a relatively higher preciseness and a shorter latency with a relatively lower power consumption. When the outside-in tracking function loses its tracking due to some limitations, the inside-out tracking function can seamless provide the pose data of the head-mounted device120and the hand-held controller180.