Published on Aug 15, 2016
Finger-tracking is usage of bare hand to operate a computer in order to make human-computer interaction much more faster and easier.
Fingertip finding deals with extraction of information from hand features and positions. In this method we use the position and direction of the fingers in order to get the required segmented region of interest.
Finger pointing systems aim to replace pointing and clicking devices like the mouse with the bare hand. These applications require a robust localization of the fingertip plus the recognition of a limited number of hand postures for “clicking-commands”.
Finger-tracking systems are considered as specialized type of hand posture/gesture recognition system.
The typical Specializations are:
1) Only the most simple hand postures and recognized.
2) The hand usually covers a part of the on screen.
3) The finger positions are being found in real-time
4) Ideally, the system works with all kinds of backgrounds
5) The system does not restrict the speed of hand movements
In finger –tracking systems except that the real-time constraints currently do not allow sophisticated approaches such as 3D-model matching or Gabor wavelets.
Color Tracking Systems
Correlation Tracking Systems
Contour -Based Tracking Systems
The FingerMouse system makes it possible to control a standard11 mouse pointer with the bare hand. If the user moves an outstretched forefinger in front of the camera, the mouse pointer follows the finger in real-time. Keeping the finger in the same position for one second generates a single mouse click. An outstretched thumb invokes the double-click command; the mouse-wheel is activated by stretching out all five fingers.
Three applications based on Finger- tracking systems are:
The FingerMouse system makes it possible to control a standard11 mouse pointer with the bare hand. If the user moves an outstretched forefinger in front of the camera, the mouse pointer follows the finger in real-time. Keeping the finger in the same position for one second generates a single mouse click. An outstretched thumb invokes the double-click command; the mouse-wheel is activated by stretching out all five fingers. The application mainly demonstrates the capabilities of the tracking mechanism. The mouse pointer is a simple and well-known feedback system that permits us to show the robustness and responsiveness of the finger tracker. Also, it is interesting to compare the finger-based mouse-pointer control with the standard mouse as a reference. This way the usability of the system can easily be tested
Figure: The FingerMouse on a projected screen (a) Moving the mouse pointer (b) Double-clicking with an outstretched thumb (c) Scrolling up and down with all five fingers outstretched
There are two scenarios where tasks might be better solved with the Finger Mouse than with a standard mouse:
Similar to the popular touch-screens, projected screens could become “touchable” with the FingerMouse. Several persons could work simultaneously on one surface and logical objects, such as buttons and sliders, could be manipulated directly without the need for a physical object as intermediary.
For standard workplaces it is hard to beat the point-andclick feature of the mouse. But for other mouse functions, such as navigating a document, the FingerMouse could offer additional usability. It is easy to switch between the different modes by (stretching out fingers), and the hand movement is similar to the one used to move around papers on a table (larger possible magnitude than with a standard mouse).For projected surfaces the FingerMouse is easier to use because the fingertip and mouse-pointer are always in the same place. Figure 6.5 shows such a setup. A user can “paint” directly onto the wall with
his/her finger by controlling the Windows Paint application with the FingerMouse
The second system is built to demonstrate how simple hand gestures can be used to control an application. A typical scenario where the user needs to control the computer from a certain distance is during a presentation. Several projector manufacturers have recognized this need and built remote controls for projectors that can also be used to control applications such as Microsoft PowerPoint. Our goal is to build a system that can do without remote controls.
The user's hand will become the only necessary controlling device. The interaction between human and computer during a presentation is focused on navigating between a set of slides. The most common command is “Next Slide”. From time to time it is necessary to go back one slide or to jump to a certain slide within the presentation. The Free Hand Present system uses simple hand gestures for the three described cases. Two fingers shown to the camera invoke the “Next Slide” command; three fingers mean “Previous Slide”; and a hand with all five fingers stretched out opens a window that makes it possible to directly choose an arbitrary slide with the fingers.
The BrainStorm system is built for the described scenario. During the idea generation phase, users can type their thoughts into a wireless keyboard and attach colors to their input. The computer automatically distributes the user input on the screen, which is projected onto the wall. The resulting picture on the wall resembles the old paper-pinning technique but has the big advantage that it can be saved at any time. For the second phase of the process, the finger-tracking system comes into action.
To rearrange the items on the wall the participants just walk up to the wall and move the text lines around with the finger. Figure 6.2b-d show the arranging process. First an item is selected by placing a finger next to it for a second. The user is notified about the selection with a sound and a color change. Selected items can be moved freely on the screen
Finger-tracking system with the following properties:
• The system works on light background with small amounts of clutter.
• The maximum size of the search area is about 1.5 x 1m but can easily be increased with additional processing power.
• The system works with different light situations and adapts automatically to changing conditions.
• No set-up stage is necessary. The user can just walk up to the system and use it at any time.
• There are no restrictions on the speed of finger movements.
• No special hardware, markers or gloves are necessary.
• The system works at latencies of around 50ms, thus allowing real-time interaction
• Multiple fingers and hands can be tracked simultaneously.
Especially the Brainstorm system demonstrated, how finger tracking can be used to create “added value” for the user. Other systems that allow bare-hand manipulation of items projected to a wall, as done with Brainstorm, or presentation control with hand postures, as done with Freehand Present. It is possible, though, that the same applications could have been built with other fnger-tracking systems