Processing Algorithm For Laser Keyboards Computer Science Essay

The user interface which we use to interact with some type of computer is a hardware device called the computer keyboard. There have been extreme changes in the keyboard layouts which have evolved in to the designs like those of the DVORAK and QWERTY keyboards. Then came up the digital period where almost anything is in the digital form making things simpler to use and smaller in size.

As the demand for much more computing conditions have developed, new individuals - computer interfaces have been applied to provide multi-form interactions between users and machines. Nonetheless, the basis for most real human to computer interactions remains the original computer keyboard and mouse. Typical keyboards are relatively measured, comfortable and effective. However, these are difficult to transport and often require wiring. To triumph over these problems a smaller and much more mobile touch - typing device has been suggested which doesn't have any physical support. This device is recognized as virtual keyboard or zero - form - factor software.


In 1999, a proposal was made to use a single tiny sensor to observe the user's fingertips transforming movements into keystrokes. The primary idea was to make a key pad out of receptors and light, projecting it on desktops, aircraft tray desks and any other flat work surface. This started a new concept of utilizing a keyboard with a new interface. The digital key pad was designed in a way to replace laptops mechanised keyboards, making the devices thinner and lighter. The online keyboard can be an unbreakable, washable keypad, projected onto a set surface used in clinic operating rooms, space vehicles and in other computerized environments.

Types of Virtual Keyboards

2. 1 On - Screen keyboard

The on-screen keyboard is built together with the windows operating system. This started out a revolution of digital keyboards in this digital era. It allows users with mobility impairments to type data by by using a pointing device or joystick. It offers a minimum level of functionality for many people with mobility impairments and also helps users who do not know how to type. It can be used even though there is no external keyboard. It is also referred to sometimes as hot electronic keyboard.

A range of advanced functions have been empowered to make the on-screen typing easier, faster and even more accurate. It let us the users to type accurately and faster by recommending words predicated on taps. This technology works similar to the one available in modern mobile phones and communicators, enabling faster and appropriate typing by suggesting the correct words after getting into a few icons. This keyboard will be more ideal for users of TabletPC, Ultra-mobile Computer, PanelPC, CarPC and similar touch-screen devices. The picture below is that of an on-screen computer keyboard.

Figure 1(Tan, D. S. , Keyani, P. , and Czerwinski, M. 2005)

Affordances of On-Screen Keyboard

Replacing physical computer keyboard

The on-screen computer keyboard is designed in such a way that, it replaces the physical computer keyboard. Folks using the computer systems will see its usage quite definitely helpful.

Can do all the task

It functions exactly like an ordinary computer keyboard having all the QWERTY keys. It also helps the users from the boring work of typing.

2. 2 Laser Keyboard

The laser computer keyboard actually replaces the original keyboard. This is placed on almost any flat surface. It could be automatically linked to the nearest device available using the bluetooth technology. It really is about the size of a small cellular phone and enables the users to type text messages or e-mails as easily as just like a ordinary keyboard.

It runs on the light projection of the full-sized computer keyboard on nearly every surface. Used with PDA's and Smart Cell phones, the virtual keyboard provides a sensible way to do e-mail, term handling and spreadsheet duties, permitting the users to leave laptop computers and computer systems at home. The electronic keyboard adjustable technology studies the user's finger moves to interpret and record keystrokes. As the electronic keyboard can be an image projected by light, it disappears completely you should definitely in use. The picture shown below is that of a laser keyboard.

C:\Documents and Adjustments\s507046\Desktop\laser_keyboard. jpg

Figure 2 (Tomasi, C. , Rafii, A. , and Torunoglu, I. 2003)


I-Tech's judgment was to build from scratch. In the process, they designed sensors based on a variety of guidelines, from the special- purpose structured-light devices called "beam trangulators" to methods based on the measurement of energy and phase1 of coming back light pulses invented by Canesta's Cyrus Bamji.

The main hardware modules found in the structures of the electronic keyboard are classified into three modules specifically 3-D optical camera, visible responses and a handling platform. The camera is connected to the platform and also to the Laptop or computer via USB 2. 0 user interface. Using serial interface the feedback communicates with the computer system. The sensors in the camera are designed so which it avoids all the background light. Alongside one another, they cost a lower amount than a mechanical keyboard, and pull less power when compared to a cell phone. The producing system "feels" almost such as a mechanical keyboard, even if users feel only the impact of these fingertips on the projection surface when keying in.

The optical system tasks the computer keyboard onto the typing surface; its infrared light source generates an invisible, fan-shaped beam grazing the top; and its own sensing system includes a processing unit. Each is in fixed comparative positions; no individual adjustment is necessary. The projector is put high on the web host device. In the easiest sensor, the camera appears down at the keying in surface at a shallow perspective through a wide lens sensitive and then infrared light. A finger stunning the typing surface breaks the infrared beam, thereby becoming visible to the camera. Triangulation then establishes the position of the finger on the typing surface.

Even with this simple sensor, implementation of the projection computer keyboard under the constraints of weight, size, power, cost, reliability, and usability has included formidable technical troubles.

Keyboard projection:

Most current optical-projection systems face mask light to form images far away. For instance, in a glide projector, the slide itself blocks part of the light reaching it; the remaining light helps it be through the zoom lens and onto the display, creating the image. This is the basic technique found in the projection of the computer keyboard on a flat surface.

Finger light and sensing:

When typing, a user's useful action occurs in the skinny layer of space that separates the hovering and constantly moving fingers from the surface of the keyboard. In the perfect world, an infinitesimally skinny sheet of infrared light grazing the typing surface could be used as a trip switch; whenever a finger intersects the beam, it could also be touching the surface. In this situation, a finger that becomes obvious to the camera is a finger that hits a key, and everything that is remaining for the sensor is identifying the finger's position by triangulation.

Affordances of Laser Keyboard

Easy to use

The laser beam keyboard is super easy to utilize. It gets connected for an available computer system easily without much effort.

Easy to set up

It is very easy to set up and requires no wiring for it. It uses the Bluetooth technology to get connected to the computer systems.


As it appears like a cellular phone, it is very much portable and can be used irrespective of the surface used for typing purposes. It can be used as a typical keyboard with versatile sensors which permit the user to improve the size of the keyboard regarding to his utilization.

2. 3 Laser Pen Keyboard

In the laser pen keyboard the detectors are attached to a tool which looks like a pen. The installation also has a projector which shows the keyboard on the display. When it's integrated with the projector it is only used as a projecting device which jobs just what is being printed out on the display. It can also be linked with a keep an eye on for browsing the display. A picture of the laser beam pen keyboard is shown below.

C:\Documents and Adjustments\S506432\Desktop\VKB\pens5. jpg

Figure 3(Retrieved from http://us. gizmodo. com/gadgets/images/laserpen. jpg)

Technical interface

The receptors in the installation used for projecting the keyboard are the infra red rays. These rays are projected on to a flat surface for better sensing of hovering of the tips. The usage of this keyboard is very convenient as it has no wires for connecting. The lithium batteries in the receptors allow us to utilize this setup continually for 2 hours of typing. It includes 63 keys and a complete size QWERTY design which allows the user to be as comfortable as he is with the typical ordinary keyboard. This also offers a stylus that allows the users to make use of the computer keyboard in a concise area where in fact the resizing of the key pad becomes essential. Among the advantages of applying this keyboard is that the size of the keyboard can be transformed as per an individual.

Affordances of Laser Pen Keyboard

Simple to utilize

The installation for the laser pen keyboard is simple to make use of. This makes the users to execute tasks in a simpler way. Laser beam pen computer keyboard can be linked to any computing device to execute input activities for the device. Connection can be made without using wires or any physical network.

Screen Projection

Laser pen key pad not only has a computer keyboard projection but also offers a screen projection. One pen does indeed the keyboard projection with numbers of keys on keyboard and the other pen does the display projection which shows the keys that are decided on and also actions done on the computer keyboard.

Working of Laser Keyboards:

The working of the exclusive keyboard includes five main modules - (1) depth map problem correction, a camera reliant module based on specific models made for the number camera, (2) backdrop subtraction, (3) central column estimation, (4) fingertip diagnosis, and (5) keystroke detection. The body shows the entire working of the basic working put in place in the design of the virtual keyboards.

Figure 4(Huan Du, Thierry Oggier, Felix Lustenberger and Edoardo Charbon 2004)

A 3D range camera is put over the source surface with a well-defined viewpoint facing the working area. How big is the working area is limited by the spatial quality of the camera. The display projector is attached to the camera which would generate the visual feedback for the keyboard and suggestions information. The camera is altered at startup. It assumes the surface as a projection matrix. The keystroke recognition is usually done through this projection matrix. That is transferred as a map and it is processed for problem correction. The error modification compensates the problems caused by the unevenness of the top. The rectified range measurements, combined with gray-scale image, are then subtracted from the reference image. It is then stored as a binary format in the matrix produced.

After making use of the central column estimation, which is defined as the pixel segments associated with hands that are good candidates for an event, by searching the neighborhood extreme in x-coordinate over the palm boundary, and applying the fingertip diagnosis by extracting features with curve modeling, specific location of fingertips are available in the side region. Finally, the keystroke diagnosis is obtained by appropriate depth curve applying another feature model, and the corresponding reaching positions are mapped back to the world coordinate system to infer the stricken tips. The updated key status is then sent to visual feedback component to generate refreshed display.

The visual opinions module projects a dynamically generated image on to a LCD. If the algorithm used, detects a key-striking event on the surface, an UPDATE order is sent. The command contains the specific key information. It posts the generated display and an individual can see the change of computer keyboard image as a textual or graphical update.

The information supplied by the camera allows developing a few simpler and more efficient algorithms to estimate the positioning of fingertips and also to locate the equivalent key. Simpleness and efficiency are fundamental elements to enable real-time and even lightweight applications.

Future and Range of the Task:

Users see this as an growing technology which helps as an interface to hook up to the digital world. Though its use has been limited to fewer applications now, as users learn more about this, it can be expected that users because of this virtual keyboard increase in the near future. However there are many obstacles in this job. The main downside is that of light scattering and close goal. And due to this the image image resolution becomes low and restricts the user to utilize it with a sizable view screen.

In the future, we may expect that these said down sides will be fixed and virtual keyboard will be used on flat surfaces and also on unequal surfaces. The keyboard could also be used on any type of surface like drinking water and so on, so the user may use the keyboard if ever and where ever necessary.


More than a decade ago, (Make Weiser, 2000) of Xerox PARC, said, "By far the most profound technology are the ones that disappear. They weave themselves in to the fabric of day-to-day life until they are really indistinguishable from it". This important unobtrusiveness is the key metric of validity for the fledgling field of electronic digital understanding technology.

The virtual keyboard can be termed a great invention in the digital world. Users look onward for this being used in a far more effective way than before. Users can also expect the inventors to make an improvement of it in such a way that it could be used on any kind of a surface.

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