Graphics tablet

from Wikipedia, the free encyclopedia

A graphics tablet (also digitizing tablet , digitizer , pen tablet ) is a pointing device for computer input. The tip of a special pointing tool, usually a pen called a stylus or a puck-shaped computer mouse with crosshairs, is moved on the tablet. The pointing device sends out impulses through which the tablet receives information about the coordinates, the pressure of the pen and additionally pressed buttons at the respective position. This process of capturing data by tracing the pen or by pressure is also called digitization. With advanced models, additional information such as pen tilt, pen rotation, finger pressure or multiple tools can be recognized. In contrast to a touchscreen , which is also available for pen operation, nothing can be displayed on a graphics tablet by the computer, it is purely an input device .

Graphics tablet from the manufacturer Wacom

technology

Inductive sensor circuit board of an inductive graphics tablet
Electronics from the active pen of an inductive tablet. The coil on the right is in the tip of the pen

Depending on the system and manufacturer, different techniques are used for position detection - a combination of these techniques is also possible.

In capacitive systems, a change in the electrical capacitance in certain areas of the surface enables position determination. In the case of resistive tablets, the position is determined by pressure on the surface, which triggers a change in the electrical resistance in certain areas of the surface and thus allows position determination. A common method for graphics tablets is the inductive transmission system shown in more detail below with the following properties:

  1. Selective, two-dimensional position determination of the pen, which is guided over the tablet. The selectivity suppresses interference, for example from the hand. The position is determined in the tablet electronics, tailored to the properties of the pen.
  2. If there is no battery in the active input pen for the power supply, the inductive system also serves to supply energy to the electronics in the pen. Technically, this is implemented with inductive near-field coupling . Processes similar to those used in contactless RFID systems, in which the electronics of the transponder are supplied with electrical energy by the reader during the readout process, are used.
  3. A suitable form of wireless data transfer between tablet and pen, which allows additional information to be transmitted. This includes, for example, the information about different buttons on the pen, the pressure intensity that is exerted on the tip and which is picked up by a pressure sensor, with some makes the pen inclination and additional information such as unique identifications of certain pens for automatic tool switching.

The inductive system based on RFID technology avoids incorrect identification, for example by the hand or fingers that are in the area or on the tablet. The main difference from a technical point of view to an RFID system is the ability to precisely determine the position of the pen, a property that is not necessary with RFID transponders.

With the inductive position determination, there is a sensor circuit board with several horizontal and vertical conductor tracks in the tray under the surface , as shown in the adjacent figure. The vertical conductor tracks are routed on one side and the horizontal conductor tracks on the opposite side. These conductor tracks are connected to groups of several 10 coils that can be switched over by the electronics of the tablet . The position of the coils on the circuit board is known exactly and the position of the pin can be determined in the arrangement formed by cyclic switching of short alternating current signals.

Different tools

Large-format graphics tablet: the coil in the puck is clearly visible

As an alternative to the pen, a so-called puck can be used, which is moved over the tablet like a computer mouse and with the help of a crosshair enables more precise aiming on the tablet and thus the digitization of templates. In this case, the coil is usually placed visibly around the crosshairs. Some manufacturers offer different pen tips for a haptic perception adapted to the simulated tool , through to tools that are modeled on an airbrush .

If different tools are offered, an identification signal of the tool is often automatically transmitted to the tablet, which saves switching the tool by hand and enables individual settings for each pen, just like with classic drawing tools.

Most graphics tablets also have keypads in addition to the contact-sensitive area, and sometimes also virtual keypads on the edge of the area in order to be able to quickly access program functions or change the settings of the current tool.

advantages

Accuracy and handling

Controlling the cursor with a pen has several advantages:

  • The control of brushes and comparable tools in graphics applications is much more precise with a graphics tablet than with the mouse.
  • Where shapes can only be indicated with a mouse, whole pictures can now be really painted and drawn precisely. The pen is guided by the sensitive muscles of the fingers and explicitly the index finger, while the mouse is guided by the entire hand over the elbow bones and the wrist.
  • Since the signal from the pen can penetrate paper, it is possible to trace drawings on paper in the computer.
  • Some graphics tablets also enable recognition of the angle at which the pen is positioned to the tablet.
  • Program functions can be assigned to special keys on the tablet surface.
  • Operation is more intuitive; People who are not familiar with using the mouse (but who can write) can also use a stylus.

Pressure sensitivity

Possibilities in dealing with pressure sensitivity. The bottom line shows the additional color change due to a gradient

Graphics tablets or their pens can evaluate the pressure intensity, for example in order to control the brush size or opacity in graphics software (see picture) and to control the application and removal of material or its deformation in three-dimensional space.

Absolute positioning

Unlike the PC mouse, which only recognizes relative movements, the graphics tablet has absolute coordinates, with roughly every point on the tablet corresponding to a point on the screen. With the mouse, on the other hand, the mouse pointer is "moved further" from its current position.

Example: If you want to select a point on the screen, you must first move the mouse there. With a graphics tablet, on the other hand, you “press” the relevant point directly. The pointer is placed immediately when the pen is on the tablet without pressure or hovers over it at a short distance. A little more pressure then translates into a click.

In professional use, this enables the exact tracking of the lines of paper templates in order to digitize drawings such as construction plans . Such work is not possible at all with the mouse.

disadvantage

  • If you work with both a keyboard and a tablet, you first have to put down the pen before typing with both hands. Picking up and repositioning the pen again is more time-consuming than reaching for the mouse, which eliminates repositioning.
  • Large graphics tablets take up a lot of desk space, while smaller models have limited usable area.
  • A small tablet should not be used in conjunction with a high-resolution monitor, because precise positioning due to the difference in size (more pixels on one area of ​​the tablet) is very strenuous and quickly tiring.
  • Programs that affect the behavior of the mouse will not work properly. For example, in some games the position of the cursor is changed. Since this is not possible with a tablet, the program will malfunction if z. B. the unchanged position of the cursor is processed as a new movement.
  • If the same menu items are selected or actions are carried out, the surface of the tablet is scratched more strongly in certain places. This, in turn, wears out the pen more and the sensitivity suffers.

Areas of application

Graphics tablets have made activities (e.g. painting, drawing on the PC, etc.) possible and have become an important aid in the following areas:

  • Digital image processing and digital painting : Modes (tools) can be selected much faster and corrections can be carried out more precisely. The exposure can be improved with pinpoint accuracy and doses.
  • Design (graphic, industrial, textile and fashion design): Quick sketches to illustrate ideas are sometimes only made digitally. The advantage here is the quick digital exchange of the drafts (compared to paper sketches, no scanning is necessary). The same applies to illustrations. Modern CAD software sometimes already offers special program-internal functions for the new way of working - the conversion from sketch to finished object is faster and more intuitive.
  • Audio and video processing (film and television): Matte paintings (digitally painted film sets ) have long been an integral part of films and are now almost exclusively produced in digital form. The advantages are flexible working with layers and the elimination of time-consuming scans.
  • Presentation: When presenting on a projector, notes can be quickly inserted with a graphics tablet or, especially during lectures, mathematical calculations can be quickly calculated and digitally saved at the same time.
  • Online tutoring in virtual classrooms: Newer forms of tutoring - especially when learning support is outsourced (see Offshore Tutoring ), require working with a graphics tablet and the visualization of what has been written on a "shared whiteboard ". This usually happens in a virtual classroom (or virtual conference room). This combination of "application sharing" and the graphics tablet replaces pen and paper. Online tutoring in the form of “live e-learning ” is becoming increasingly popular, especially in the English-speaking world. In the German-speaking world, this new form of tutoring is comparatively little widespread.
  • 3D computer graphics : In this area, programs such as ZBrush or Mudbox make creating detailed models much easier. In this type of program you paint and influence the geometry with tools, the effects of which are particularly dependent on the pressure.
  • One application that has become unusual today is the use of a graphics tablet as the user interface for a CAD program. Only a small part of the tablet was used as an input area for the screen, while the buttons for operating the program were arranged around this area.
    The trays used for this purpose typically had a work surface of 12 "x 12" (around 305 mm x 305 mm) or 12 "x 18" (around 305 mm x 457 mm). The user interface was in the form of an imprint on a sheet of paper or plastic, which was placed under the transparent cover of the tray. Corresponding requirements for common programs such as AutoCAD were supplied with the tablet, and the software packages also included tablet supports. The software also provided the associated drawing files for these, so that the user interface could be customized and printed out.
    Due to their role as a substitute for the mouse, these tablets normally did not have a detection of the pressure applied. Pucks with 4 or 16 keys and pens with two or three keys were used as input devices. Common manufacturers of these tablets were, for example, Summagraphics / Calcomp, Acecad or Genius (not to be confused with the CAD software manufacturer of the same name).
    After the originally menu-based user guidance was switched to graphic user interfaces in CAD programs from around the mid-1990s, graphics tablets, which were once an almost indispensable accessory for a high-performance CAD workstation, are almost no longer used for this purpose in everyday life. In modern 3D CAD systems, in addition to the mouse as an input device, a 3D mouse is often used for more convenient navigation.

Manufacturer

  • Wacom Co.
  • Huion
  • GAOMON
  • Hanvon Co.
  • iball
  • PenPower
  • The Logic Group
  • XP-PEN
  • Yiynova
  • Acepen

software

Basically, you can use a graphics tablet to operate any type of software with a graphic user interface that can also be operated with a mouse, but the following applications, for example, use the technical possibilities accordingly:

Corresponding variants of Microsoft Windows operating systems have been developed for tablet PCs , which are optimized for keyboard-free work with the pen. Handwriting recognition is integrated, which also evaluates biomechanical properties such as writing pressure and pen inclination (if available). In general, the operating systems have been adapted to the operation without the usual keyboard through various special features. Software that is designed for operation with a pen is also available from other manufacturers. For Apple Macintosh , the handwriting recognition Inkwell has been integrated into the Mac OS X operating system.

Web links

Commons : Graphics tablets  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ What is digitizing tablet? Webopedia definition. Accessed June 19, 2018 .
  2. ^ Jürgen Steimle: Pen-and-Paper User Interfaces: Integrating Printed and Digital Documents . Springer Science & Business Media, 2012, ISBN 978-3-642-20276-6 .
  3. ↑ Patent US4878553 : Position Detecting Apparatus. Filed September 14, 1987 , published November 7, 1989 , Applicant: Wacom, Ltd, Saitama, Japan, Inventor: Tsuguya Yamanami, Takahiko Funahashi, Toshiaki Senda. ‌
  4. ↑ Graphic Design. Retrieved June 19, 2018 .
  5. ^ John Walsh: The Logic Group Home Page. Accessed June 19, 2018 .
  6. ↑ Adobe Illustrator and Wacom Pen Tablets: A Better Way to Unleash Creativity | Wacom Community. Retrieved June 20, 2018 .