Lei feng's network (search for "Lei feng's network" public attention): this is the VR space sequel to position 7 weapon. Author Wang Rui for VR senior industry practitioners.
As previously mentioned, VR experience building now still missing the most important part is cheap and flexible and accurate positioning solutions.
About VR space positioning tool, in addition to the sense of body position, optical tracking and image recognition, space radar, HTC Vive Light House, we will continue to talk to the rest of the 2 types of weapon, and to sum up the advantages and disadvantages of the existing spatial positioning, welcomed the study.
|RTKGPS、UWB、SLAM... VR space positioning what hottie? (E) RTKGPS
Real-time difference GPS technology at least has two a part composition: in base station Shang placed receiver, on all visible of GPS satellite for continuous observation, and will observation data through transmission equipment (like number biography radio, WIFI, and public 3G/4G communications network and so on), real-time to sent to user Observatory (flow station); and in user Observatory Shang, also through GPS receiver received GPS satellite signal, while also through radio received equipment, received base station transmission of observation data, And then through the user's coordinates to calculate the relative positioning in real time, the dynamic positioning accuracy up to 1cm-2cm.
This technology not only can be used as a mapping can also be used for military purposes. Its high accuracy characteristic can be used for accurate navigation of large agricultural machinery such as combine harvesters and in machinery production and achieve a perfect combination between intensive; at home, a fairly extensive civilian scene is the driving test ... ...
Before the advent of RTKGPS, surveying and mapping industry in order to obtain a precise coordinates to cm, need to use a common GPS device to receive data, and then a lot of offline calculation. And the emergence of RTKGPS greatly developed many new scenarios, such as drones. RTKGPS belonging to a professional field, using a little-and the price is very high, but in recent years has been more and more practitioners will this technology became more populist, an example of this open source RTKGPS Kit:
(Via www.swiftnav.com)
However, RTKGPS is, after all, GPS must be outdoors you can use. Which usually plans setting indoors or shopping mall for the VR experience Center is undoubtedly a major bad news. But profound VR outdoor experience is not without precedent, for example links below video was once popular in the media and friends (but really are highly dangerous, do not try this)--the race car wearing VR helmets, cool to a friend.
It was meant to be an automobile brands and engaged in a public relations campaign in a lubricant, racers take OculusVR helmets and cars loaded on high-performance computers, so as to fully experience the pleasure of drift in the virtual space. And this adventure owes its success, one of the major reasons is the use of the RTKGPS to complete the localization, so that we can accurately know the location of car and driver, and corresponding virtual content rendering (and avoid the tidings of riders fell out).
(Vi) UWBUWB technology is a kind of wireless location technology, this technology (Ultra Wide band) also known as "ultra-wideband" position, it is a kind of pulse signal high-speed wireless short-range communication technology of data transmission, rather than General wireless communications system used by the carrier.
Principle of UWB positioning is very simple, it is using the beacon sends out pulses arrive flight time to calculate the location of the base station, and Yes, we are familiar with is the name, TOF (Time of Flight).
Don't forget to radio is based on the speed of light, so its detection precision from the theory can be very high.
UWB was originally from 60 's pulse is the definition of communication technology. UWB technology pulse length is generally in the subnanosecond level signal, which can reach thousands of megahertz bandwidth (UWB limit 3.1-10.6 GHz), the technology in 1989 by the United States Department of Defense named as the ultra-wide band technology. Which is characterized by large bandwidth, carrier-free, low power.
(Via 36kr.com)
Because bandwidth is large, so penetrating UWB technology is better. Compared to technologies such as WIFI, radio multipath effects (because the high frequency signals are straight lines, so it will bounce back and forth because the building block into several roads, it is difficult to judge) to the much weaker, so the accuracy of the positioning scheme is often better than the traditional Room-Level scheme based on WIFI (that is, determine which room in the room) much higher. Now mature UWB positioning system can even just dozens of centimeters, also has options that firm said 2-5 cm accuracy level, but the actual deployment in a variety of indoor space occasions when, basically not up to this precision. Not all venues are, after all, is an open and free of any block, no more people to participate in the big house. And don't forget the core of this technology is also a communications link, so all kinds of communications interference but also brought.
UWB itself, after all, is a wireless technology, it covers all wireless communications are within the band of noise about it, and its wall despite better than other wireless technologies, but it will still have a greater attenuation. And the UWB standard is to limit the power of, so now most of the programmes are effective at about 10 m, if it is a large indoor venues may also laid a lot of communication base station.
Therefore, if a scheme the UWB independent positioning, would still be less than severe VR experience required position accuracy positioning and distance, but if you can work with data in other ways, may want to solve the problem.
Germany famous Fraunhofer research center, there is a "black science" products is called RedFir:
(Via is.fraunhofer.de)
Install equipment in a players feet, sneakers and ball placed inside the device, and layout of the entire site after the collection of a large number of base stations, the whole stadium was transformed into a high-tech Virtual Studio, you can at any time during the process of broadcasting for data collection and analysis, the Visual work. Such a good thing, of course, have been willing to use the VR experience, just to those key problems with the wireless, I am afraid that to developers to pay a big price.
(G) deep-fried chicken: SLAM
SLAM's full name in English is: Simultaneous Localization and Mapping, simultaneous localization and map building.
In short, for space within of a robot (or no machine), if it in a completely unknown of environment in (like Tomb Raider adventure), so it on can side along ramps to in go, side with camera or laser radar to created has this ramps of digital information copies (is building map), such then had a will on can using just created of map data to himself navigation using has.
Oh, some very high-end sweeping robots, also known as using this technology.
In the movie there is a scene in the Prometheus, a drone with a laser detection ability (the ball) is thrown out, it began independent access to space information. This is a typical SLAM scenarios:
In fact, from the academic definition, robots in unknown environments began to move from an unknown location, and then move depending on position estimation and sensor data are constantly positioning itself and amendments, while building incremental map, this is the basic process of SLAM.
Of course, this approach is not necessarily just for robots, if people carry a portable computing device (or just the phone), then SLAM can also create maps in unknown environment and to position themselves, that is why we urgently need in the VR scenario features.
SLAM algorithm of a variety of data sources, such as using scanning LiDAR point cloud data, also have binocular camera with RGB images and stereoscopic vision to generate, or directly use RGBD Kinect (visible light + depth) programme and can even be seen in the lab-level based on single camera and RGB color or grayscale images to make the SLAM algorithm papers.
From another perspective, if you expect based on three dimensional space recognition technology (rather than the traditional two-dimensional code or pictures), then SLAM class means better and faster methods, but also the AR software and algorithm developers (for example, Metaio, but has been acquired by Apple) has been working to achieve goals. As SLAM on the one hand to be able to give a more precise location, as well as three-dimensional features can do for the environment gets three-dimensional reconstruction and the necessary means, to address the actual scene in the display device, and virtual images overlapped, occlusion problems AR scene may be used in the future, is also a portable wearable rigid demand.
Today, the SLAM has been widely used in VR/AR on the device, for example Microsoft HoloLens is typical RGBD SLAM scenarios. Project Tange of Google mobile phone, as well as Intel RealSense details are RGB-D SLAM. Even how many people have not seen the kind of "black science" company Magic Leap, probably impossible not to SLAM as spatial positioning and the actual mask cornerstone of judgment.
SLAM on the high-end business market, in fact, already has a very mature stories. NCAM camera system such as Virtual Studio, which doesn't require traditional electric controlling pan/tilt, can be directly mounted in the frame on the Nikon stable shooting everywhere. Get the camera position and orientation results are immediately reflected in the content creation tools, in order to achieve an animation or special effects blockbusters among the leading camera-link.
Of course, SLAM technology is not without shortcomings.
First of all, it's still based on Visual identification of signal acquisition/processing/transmission compared with other technical means, the current delay often is hard to ignore, and that's what is VR experience where the most unacceptable. Addition, SLAM on at this stage of mobile equipment for, calculation pressure still too big, Project Tango phone and HoloLens glasses for increased has a or more block Association processor, such natural and brings has power management and overheating, various problem, rumors in the Carmack also in for future of OculusVR and GearVR helmet sought based on SLAM of positioning programme, it whether can became future VR world mainstream positioning way, may currently also is a unknown just.
| New omnidirectional treadmill
Above all spatial orientation programmes are based on the same premise, that players can walk sites in accordance with their will, walking its scope limited by the site itself. If we of experience target is a paragraph in warehouse Chamber in war zombie, or in street build fortifications acting nemesis of VR game, so such of programme apparently total has comes; but if we is to a paragraph GTA5 as of Super big as target, or is can unlimited and exploration down of sand box game, so again big of site I'm afraid also enough players toss...... And space bigger, more complex structure and shape, position that corresponds to the installation and maintenance costs higher, in order to maintain a stable location algorithm and accuracy more difficult.
Fortunately, there are people who will look for other ways, such as in people's daily fitness treadmill, join in addition to speed control of directional control, became known as the Omni-directional treadmill (Omni-directional treadmill):
(Via think-about.pl)
Design of an omni-directional treadmill is not however went hunting one with touch screen and MP3 function of treadmill thing, here are two huge question developers need to think:
, How to identify players in a treadmill speed and direction;
Second, how limitations in Center for devices running the player, or he was not aware that the premise of his "back" facility?
Omnideck is an early launch of the above solutions, it uses a group of players as the center of the radial motion of the conveyor belt. When players come to you any belts, direction sensor will sense the player's movement and speed, drive belt to send players back to the Center.
(Via walkmouse.com)
It is easy to imagine, in which equipment mainly depends on the number of radial belt. Once increased the number of conveyor belt, it will bring more heavy maintenance costs, the sensor accuracy, as well as their own weight. Moreover in such a huge space for only one game, from a revenue point of view may be living beyond their means. Therefore, a lot of focus on walking VR experience company immediately launched a programme that looks more reasonable, such as Virtuix Omni in the figure below:
Omni running machine itself can as a is a cooking with of not stick pot pot (actually it of material does is not stick pot of material), it of chassis was design into a surface SAG of round surface, and by many small concave slot of smooth radial runway composition, above is a can regulation bracket, up to protection players and recognition Xia squat/jumped up action of function, total weight about for 50 kg, and user need wear Shang special of shoes only can in Omni of runway Shang movement--more accurate to said, Is sliding on the runway. This design can be more lightweight and flexible than the former, the key lies in this "foot could not be left in the bottom of the sliding Center" feature, and Groove around the sensor system is responsible for measuring user movement direction and speed, so as to simulate the players marched in virtual space.
Principle, this programme looks perfect, just more cumbersome to wear, to the domestic market would still have the distance. However, judging from the actual user feedback, "foot slide step" movement is not to make them feel comfortable. Might even be a feeling in the song:
Little mouse,
On the lampstand;
Oil theft--
Is there less bulky, sensitive and accurate, will not make the player feel uncomfortable to run option? There may be:
(Via mobilemag.com)
Infinadeck full to running machine since birth of day up on attract has many media and industry people of concern, it of basic idea actually and no very complex of place: used motor led belt round of way, using a whole article along y axis movement of big belt round, led more article along x axis movement of small belt round, such players in two a axis up of movement are can was recognition and records down. The central location and the player once you leave the treadmill, the system will pass the Visual recognition or other means of identification that the direction and distance of the player, and start the motor to send players back.
Of course, this design also has two small bridges to cross. First is the weight problem, so many motor and pulley was placed on top of a piece of equipment, its load-bearing pressure is probably quite small, non-mechanical structure as a whole has to with sufficient raw material to build steel body; overall estimate down, tons of weight on such a device there, really moved to the House I am afraid it will only let downstairs neighbor was on pins and needles. Second is players of movement feel and equipment size of relationship, if equipment itself had small, belt round of perimeter also on is small, produced of friction also on different--which is easy with to players a obviously of "was pulled back place" of feel; and equipment had big although can let "back in situ" of process became smooth, is undoubtedly further increased has equipment of volume and weight, let household level of using cost became more to accept.
Infinadeck has been claimed to build inexpensive and convenient system of Omni-directional treadmill, who has yet to release updated news, and perhaps are trapped in these structures and selection of difficulties.
| Don't let your players limping
We simply summarize the previously mentioned advantages and disadvantages of various positioning options, as shown in the following table:
Programme
Cost of delay time
Recognition range accuracy
Number of disturbances of Kinect VR Shinecon headset
< 2000
>30ms4x3 meters precise roles to bone, but unstable
Up 6 people, easy lost too much of debris, extra of infrared light, strong reflection material PS Move<2000 yuan >30ms can appropriate extended distinguish role and weapons according to color ID suitable distribution more people, may will errors reported too much of debris, complex of environment and back views, block mark points, errors of camera calibration optical positioning system > 200,000 yuan <20ms can unlimited extended, but cost also with of soared precise to role bones usually not over 4 people too much of debris, complex of environment and back views, Block markers, camera calibration errors HTC Lighthouse
< 8000 yuan <20ms5x5 meters head and hands handles recommends 1 people too much of debris, not rules regional, errors of placed laser radar 140,000 20-30ms40x40 meters contact points, distance more far precision more low recommends 1 people, cannot distinguish ID too much of debris, each other block UWB?<20ms depends on base station number 15-30cm recommends 1 people too much of debris, more diameter problem, other equipment of interference SLAM?>30ms can unlimited extended, but data volume soared
Depending on pretreatment pretreatment 1 accuracy is often needed to map cannot have big site changes after Virtuix Omni<8000 gait 1 do not restrict accurate to within a step without interference, but wear complex, experience is not true Infinadeck? Step within the limited accurate gait 1?
Conclusion seems very frustrating at the moment, no programme can be said while addressing cost, multiplayer games, low latency, anti-jamming, and space restrictions these big issues.
In other words, though the author has hardships and learning to ask for help, managed to collect seven weapons plus an extra Bouns (treadmills), but still could not reach the start in the heart's desire: VR virtual space walking experience, is really an unattainable goal?
Fortunately, we have seen enough of practitioners has been started for this effort.
Author experience had Shanghai green pupil of optical positioning programme, its low delay and accuracy has do has available of level, and more low cost of products development presumably is this team next of target; Connaught also make reportedly also not meet Yu currently system key parts of high cost and relinquished, began research himself of optical positioning system; The Void more is secret received has a designed specializing in UWB positioning of team, intends to put himself of theme park positioning programme more diligence. More brain hole was wide open in the future, innovative solutions, and position means closer to the actual demand, may have also not far away.
Built and maintenance costs can be controlled, so people with the game no longer is the key problem, let your players don't become ropey – believe in VR space location's next move, will give us a surprise.
Drawings from: Engadget.com VR Shinecon headset
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