Pimp My Technology

Advantages disadvantages and applications of motion capture

Advantages

Mo cap offers several advantages over traditional computer animation of a 3D model:

More rapid, sometimes even real time results can be obtained.

The amount of work does not vary with the complexity or length of the performance to the same degree when using traditional techniques.

Complex movement and realistic physical interactions such as secondary animation, weight and exchange of forces can be more easily recreated in a physically accurate manner.

Mocap technology allows one actor to play multiple roles within a single film.

Advantages over live action A movie that contains so large amounts of CGI that the actors would have to stay in front of a bluescreen and interact with invisible computer animated characters which is added later, trying to fit into a computer animated world, it is sometimes less problematic to make everything digital, including the actors. This way, all elements would fit together naturally and have the same visual look.

The director can choose any angle he desires from a scene, including angles that would have been hard or impossible in a live action movie.

Limitless possibilities for rotating effect.

Costumes, make-up, body size and age can be changed to whatever is needed.

There is no need to have light, colors and filters in mind when filming the motions, as this will be added digitally later.

Disadvantages

Specific hardware and special programs are required to obtain and process the data.

The cost of the software and equipment, personnel required can be prohibitive for small productions.

The capture system may have specific requirements for the space it is operated in.

When problems occur it is sometime easier to reshoot the scene rather than trying to manipulate the data. Only a few systems allow real time viewing of the data to decide if the take needs to be redone.

Applying motion to quadruped characters can be difficult.

The technology can become obsolete every few years as better software and techniques are invented.

The results are limited to what can be performed within the capture volume without extra editing of the data.

Movement that does not follow the laws of physics generally cannot be represented.

Traditional animation techniques such as added emphasis on anticipation and follow through, secondary motion or manipulating the shape of the character as with squash and stretch animation techniques are generally not applicable.

If the computer model has different proportions from the capture subject artifacts may occur. For example, if a cartoon character has large, over-sized hands, these may intersect strangely with any other body part when the human actor brings them too close to his body.

The real life performance may not translate on to the computer model as expected.

Applications

Some video games use motion capture to animate athletes, martial artists, and other in-game characters.

Movies use motion capture for CG effects, in some cases replacing traditional cell animation, and for completely computer-generated creatures, such as Gollum, The Mummy, and King Kong.

In producing entire feature films with Computer animation, the industry is currently split between studios that use Motion Capture, and studios that do not. Out of the three nominees for the 2006 Academy Award for Best Animated Feature, two of the nominees (“Monster House” and the winner “Happy Feet”) used Motion Capture, and only Pixar’s Cars was animated without Motion Capture. In the ending credits of Pixar’s latest film “Ratatouille,” a stamp appears labelling the film as “100% Pure Animation — No Motion Capture!” On the other hand, Pixar’s parent The Walt Disney Company has announced that it will distribute Robert Zemeckis’s “Christmas Carol” to be produced using “Performance Capture,” the motion-capture approach that Zemeckis first used on “Polar Express.”

Virtual Reality and Augmented Reality require real time input of the user’s position and interaction with their environment, requiring more precision and speed than older motion capture systems could provide. Noise and errors from low resolution or low speed systems, and overly smoothed and filtered data with long latency contribute to “simulator sickness” where the lag and mismatch between visual and vestibular cues and computer generated images caused nausea and discomfort.

Gait analysis is the major application of motion capture in clinical medicine.

High speed—high resolution active marker systems can provide smooth data at low latency, allowing real time visualization in virtual and augmented reality systems. The remaining challenge that is almost possible with powerful graphic cards is mapping the images correctly to the real perspectives to prevent image mismatch.

Motion capture technology is frequently used in digital puppetry systems to aid in the performance of computer generated characters in real-time.

by

Antony

GSM phones use encrypted technology that enables secure voice and data transfer during calls. GSM technology uses an algorithm to ensure the authenticity of the caller and the integrity of the channel, even when you are roaming in a foreign country.

The most interesting, and potentially contentious area of wireless security is that concerning wireless LANs or Wi-Fi networks, these are fast becoming the connection method of choice. Wireless signals do not recognize corporate or geographical boundaries and are only limited by the propagation configuration of the network. Even in an office environment you will find small areas or “blind spots” where the coverage is very weak or non-existent. So, it is possible for the random surfer to “happen upon” on someone else’s network. How can one?protect against this happening?

Wireless local area networks use spread-spectrum technology – a technique that makes the radio signals difficult to intercept. Most Wi-Fi systems also include a form of user logon and password protection. Of course, the spread spectrum signals can be intercepted with a relatively simple wireless card and many networks do not properly set up the password feature and will allow ready access to anyone. The fact that “employees” have to go through some form of physical security before they can access the network only adds to the notion that wireless networks may not be as secure as equipment manufacturers would have us believe.

The problem with wireless security is essentially a technical issue with the way the signals are encrypted. The original wireless LANs (WLANs) used the Wireless Encryption Protocol (WEP). This was then replaced in late 2002 with the Wi-Fi Protected Access (WPA). Essentially, WPA offered improved data encryption through the use of temporal key integrity protocol (TKIP). The TKIP feature scrambles the keys using a hashing algorithm and ensures that the keys have not been tampered with. WEP only uses a static key that is seldom changed by users. This cryptographic weakness caused many of the security breaches in WLANs because intruders could, with relative ease, generate an encryption key and access a wireless network.

While WPA offers enhanced security features over WEP, not all industry observers are completely satisfied. A recent problem was highlighted with WPA concerning the use of poorly chosen passwords for a network. Criminals intent on compromising a WLAN can use simple dictionary software to overcome the system password. In fairness, this weakness only manifests itself when short, text-based keys are used and does not signify a fault in the WPA protocol. WLAN manufacturers can circumvent this problem by incorporating the ability to generate random keys across the network and putting in place user requirements concerning the length and style of passwords.

Microsoft responded to this potential threat by providing a Windows XP download that alters the way the operating systems communicates with the Wi-Fi network – using separately generated keys for each system user rather than one, albeit encrypted, key for the network connection

Verizon Wireless Phones come in a variety of makes and models, most running on 3G technology even as the carrier is busying installing their 4G network. BlackBerry Cell Phones for Verizon are among the most popular of brands available, with a feature set that defines it as, more properly speaking, a smartphone.

2G technology is the most widely used network technology for mobile phones. More than 80% of cellular phone users around the world use 2G technology at present. One disadvantage that 2G technology has compared to 3G is that data rates are limited – it is relatively slower than 3G. Lower data transfer speed means slower music and video downloads, problems when making a video conference call, or long waits for sending/receiving large media messages.

That is the main reason for the development of newer network technologies such as 3G that offer a data transfer speed of up to 2Mbps (2 Mega Bits per second). Anyone using a 3G phone knows that that is far from being true; in fact, it almost never exceeds 384Kbps, at most.

A new technology being developed these days, 4G, will supposedly allow data transfer speeds as high as 100Mbps (50 times faster than today’s 3G!) outdoors, and a blasting 1Gbps indoors.

So what are the main features of 4G technology?

- Wireless internet with a bandwidth much wider than the 2G or the 3G – 100 MHZ.
- Much higher data transfer speed – up to 1Gbps.
- Video conference calls – with more than 2 callers, and due to the faster data transfer rates, less problems; also, will not get stuck as often as it does with 3G.
- Improved security features to prevent frauds and theft.
- On account of the wider bandwidths, data transfers will be relatively cheap

There are not enough details about 4G technology to compare with other technologies. Without a doubt it will be better, faster, and probably cheaper, but all users would have to get the new devices, meaning compatible devices (which probably aren’t going to be cheap), and wait for the new networks and antennas that will go with this newest technology.

Anyway, NTT DoCoMo, the Japanese company working on devloping 4G technology in association with HP, estimates that 4G services will be launched (in Japan only) somewhere between 2010-2016, and it will probably take a couple more years after that for it to get to the United States so that we still have plenty of time to adjust and get ready.