ngách

ngách

Kết quả (Anh) 1:

niche

Kết quả (Anh) 2:

the village

Kết quả (Anh) 3:

4.3 Tracking Technology for Mobile AR SystemsIt is well known that for AR to be able to trick the human senses into believing thatcomputer-generated information coexist with the real environment, very accurateposition and orientation tracking is required.As seen in the AR systems section, the most common type of tracking systems for mobile systems is by combining a few complimentary tracking techniquesto comprise the advantages of both and support the disadvantages of the other,which creates hybrid tracking. Outdoors systems make mostly use of GPS andinertial tracking technique with the use of accelerometers, gyroscopes, electroniccompasses and/or other rotation sensors, along with some computer vision trackingI don't want to be GPS system, although lacking in precision, provides an easy trackingsystem for outdoor systems that allow for better estimating the position of the userand its orientation once coupled with some inertial sensors. In this way, the user'sinterest point is narrowed down and allows for easier visual tracking with feweroptions. Gps systems could not be used to unite visual tracking with inertialtechniques only. Visual tracking achieves the best results with low frequency motion,but are highly likely to fail with rapid camera movement, such as the ones that willoccurs with HMDs. On the other hand, inertial tracking sensors perform best with high frequency motion while slow movements do not provide good results due to noise and bias drift. The complementary nature of these systems leads to combiningthey come together in most hybrid systems.Other systems, such as [23] and [42], rely on computer vision for tracking,but most are indoor systems with which the environment can be somewhatcontrolled. When it comes to visual outdoor tracking, a couple of factors, suchas lightning, make tracking extremely difficult. Moreover, some objects presenttracking difficulties. One of the most advanced visual tracking mobile systems isGoogle Goggles [51]; however, this application can only track objects of regularform such as barcodes and books, or places thanks to its GPS and accelerometer thathelp the application recognize where the user is standing and the user's orientationto narrow down the options. Google Goggles can't recognize things of irregularshapes such as leaves, flowers or food.