Hand tracking

Giving a tactile sensation to holography, besides of course a projection of a floating three dimensional image, among others a tracking system is needed, which works as an interface between hologram and human. As it is shortly shown in the attached video in entry Touchable holography a Wii Remote can be used as a simple tracking system.

Johnny Chung Lee gives a little more detailed view on how the Wii Remote tracking system works. Even he applies it in another context than holography, that ought to be shown below, because the mechanics behind it is of the same kind.

Wii Remote tracking system

"While camera-based and marker-less hand tracking systems are demonstrated these days, we use Wiimote (Nintendo) which has an infrared (IR) camera for simplicity. A retroreflective marker is attached on the tip of user's middle finger. IR LEDs illuminate the marker and two Wiimotes sense the 3D position of the finger. Owing to this hand-tracking system, the user can handle the floating virtual image with their hands."

To give a more complete understanding of how touchable holography - as Shinoda Lab from University of Tokyo presents it at SIGGRAPH 2009 - works, another entry about airborne ultrasound tactile display is added.

The snippet attached below wants to illustrate what Johnny Chung Lee is talking above about Minority report.

Minority report (2002)

This movie forestalls the technology of hand tracking several years prior it finds application in combination with holography. So to say the technology catches the phantasm of user interface including hand tracking.

Compression locus of a simultaneity

Unprejudiced information by redundancy describes an odd viewing pattern which offers any which ever possible view onto an object or a scene, due to any information being available without preselection. This viewing pattern is very comparable to that which is known from holography. A hologram offers an infinitely amount of angles. It looks like that this way of perception, which Olivia Dunham and Doug Carlin experience, finds its genesis in the way of viewing a hologram.

This entry would like to add the term of Compression locus of a simultaneity to the above mentioned concept. The following footage should be introduced to give a visual example, which should make the idea behind that a little more understandable.

The commercial below is entitled Carousel and is directed by Adam Berg. In 2009 it wins the Film Lion Grand Prix at the Cannes Lions International Advertising Festival, which is the most prestigious award in the advertising industry.

Carousel (2009)

Compared to the snippets taken from Fringe and Déjà vu, all the three of them have one thing in common. They project a virtual world in which so much unlimited more than just one angle is available to the observer.

But there is a significant difference between Fringe and Déjà vu on the one hand and Carousel on the other. The commercial by Adam Berg shows a frozen scene. This is a shot of one single moment. Everything that can be seen in this 139 seconds advert happens exactly at the same point of time. There is no prior and no after. The view of the observer moves through the scene just in the dimension of space, not in the dimension of time. This little movie unifies simultaneity in a single place, where different events meld to an entirety. Compressed on a single point. Without gaps, smooth, without increments and without in between.

From an aesthetic point of view and from a point of view of viewing pattern, Carousel reminds more of a hologram than of a movie. Despite the long single tracking shot, which could have been taken from an Alfred Hitchcock movie, it conveys a viewing pattern, that has its origin neither in film nor in photography or painting, but in holography.

Parallax view

Spacial parallax is mentioned in entry Unprejudiced information by redundancy as one feature of holography. This entry wants to illustrate the concept of this phenomenon with the help of some movie footage. Simultaneously it wants to show how a feature which is typically for holography, finds its application in other fields. Beyond holography. In this case in the field of film.

Parallax has got a greek origin and means change or divergence. It terms a virtual change of the position of an object due to the change of the observer's position. To make this a little more understandable, imagine your thumb being alternately viewed through left and right eye. The thumb seems to be jumping in front of the background. So this is caused by different angels. Both eyes and thumb form an equilateral triangle with the distance between both eyes as a basic length. In astronomy, where this phenomenon finds its genesis, it is being used for calculating distances between planets. With the thumb being substituted by a planet.

Viewing the photograph of a stake below one can neither let it jump by opening an closing ones eyes alternately nor can have a look what's behind the stake.

In contrast to that viewing the snippet below should make the point.

The Parallax View (1974)

This snippet is the establishing shot taken from movie The Parallax View. With this first scene director Alan J. Pakula visualizes the title of the movie on a level of pictorial language.

In this movie local reporter Joe Frady witnesses a murderous attack on presidential candidate Senator Charles Carroll in a restaurant on the top of the Space Needle in Seattle. Trying to investigate who is responsible for this attack, he reveals that enterprise Parallax Corporation is part of a conspiracy behind that.

"Auf den Film übertragen läßt sich formulieren, wie wenig man sich bei der Sicht der Dinge der Abhängigkeit vom eigenen Standpunkt bewußt ist und wie sehr das Verhaftetsein in der eigenen sozialisierten Identität unser Weltbild bestimmt. Der "Parallax View" - der parallaktisch verschobene Blickwinkel also - macht nicht nur vordergründig die von Frady entdeckte Verschwörung sichtbar, sondern demontiert anhand dieser Perspektivenverschiebung den identitätsstiftenden amerikanischen Mythos, indem er einen Blick auf ein Amerika bietet, dessen Geschichte bis in die Gegenwart als eine Geschichte der Gewalt verstanden werden kann"

[translation: Transferring the concept of Parallax View to the movie, it could be said how little one is aware of dependency of ones own angle regarding to the sight of affairs and how much sticking to ones own socialized identity shapes ones world view. The Parallax View not just uncovers the revealed conspiracy, but also disassemble identity-establishing american myth by offering a view onto America, which history until present time can be understood as a history of violence.]

As mentioned at the beginning the Parallax View is a feature of holography. Depending on the kind of recording, a hologram can offer a vertical parallax as well as a horizontal parallax.