Computer graphics processing and selective visual display system – Display peripheral interface input device – Cursor mark position control device
Reexamination Certificate
1998-09-11
2001-09-18
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Cursor mark position control device
C345S173000, C382S288000
Reexamination Certificate
active
06292173
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to methods of and systems for providing user input to user interfaces for computers and the like, and more particularly to a semiconductor touchpad user input device and method for controlling the X-Y position of a cursor or pointer on a display and for providing Z input to a computer.
DESCRIPTION OF THE PRIOR ART
Pointing devices are commonly used in conjunction with computers to control the movement of graphical cursers or pointers on display screens and to select objects and operate controls displayed on the screen. For desktop computers and work stations, the most commonly used pointing device is a mouse. As is well known, a mouse is moved over a flat surface to control the position of the pointer on the display screen. The mouse includes one or more buttons that may be pressed or clicked to perform operations on objects and controls displayed on the screen.
Recently, small laptop and notebook computers have become very popular. Laptop and notebook computers may be used in conjunction with a docking station so that a standard keyboard, mouse, and CRT display may be used for the user interface. However, laptop and notebook computers are designed to be used while traveling away from the office or home. In such remote locations, the user does not always have available a flat surface upon which to use a mouse. Accordingly, laptop and notebook computers typically have a built-in pointing device, such as a track ball, touchpad, or a pressure-actuated pointer device, such as the IBM TrackPoint(TM) device.
In addition to computers, certain television and set top box systems include a graphically user interface for enabling a user to input information to the system and change or control system settings. The user input device for such systems is typically a hand-held infrared keypad controller. Such controllers may include devices similar to those used in laptop and notebook computers to control the position of a pointer on the television screen. Trackballs, touchpads, and pressure-actuated pointing devices have certain drawbacks. For example, while trackballs are compact, they require consider finger movement to produce large pointer displacements at low velocities. In addition, trackballs are mechanical devices that may not be well suited for operation in dirty environments.
A touchpad comprises a rectangular surface that is mapped to correspond to a display screen. By touching the location on the touchpad, the user causes the computer to move the pointer to the corresponding location on the screen. Since a typical touchpad is substantially smaller than the screen, accurate positioning of the pointer can be difficult. In order to be useable, a touchpad must be large enough to permit the user to position the pointer accurately. The large size of touchpads makes them relatively expensive.
Pressure-actuated pointing devices include strain gauges or transducers that detect the direction and magnitude of the force of the user's finger on the device. The pointer is moved in a direction corresponding to the direction of the force and to the speed corresponding to the magnitude of the force. Certain individuals have trouble using pressure-actuated pointing devices to position the pointer accurately on the screen. One source of trouble is inertia, whereby the pointer continues to move after the user releases the pressure on the device.
In U.S. application Ser. No. 09/012,065, filed Jan. 22, 1998, by A. Ferrari and M. Tartagni, entitled “Touchpad Providing Screen Cursor/Pointer Movement Control”, there is disclosed a touchpad device that includes a matrix array of capacitance sensors. The array of the invention can be used initially to acquire a user fingerprint for use in a user identification procedure that occurs during logon to a device such as a laptop or palmtop computer. Subsequently, the array is used to provide user input to the computer. By using the array both for user identification and for user input, the cost of the relatively large array is justified.
It is an object of the present invention to provide an improved capacitance touchpad user input device.
SUMMARY OF THE INVENTION
Briefly stated, the present invention provides method of and system for providing user input to a computer. The system of the present invention captures a first finger position image at a first time and a second finger position image at a second time. The first and second finger position images each comprise a plurality of numerical gray scale values equal to or greater than zero. The system then subtracts the first finger position image from the second finger position image to obtain a composite image. The composite image has a first region comprising numerical values less than zero and a second region comprising numerical values greater than zero. The system provides X-Y input to the computer based upon the relative positions of first and second regions. The system further provides Z input to the computer based upon the relative sizes of said first and second regions.
The system of the present invention provides X-Y input by computing a centroid for each of the first and second regions. Then the system subtracts the centroid for the first region from the centroid for the second region to obtain a displacement vector. The system moves a pointer in the X-Y plane according to said displacement vector.
The system of the present invention provides Z input to the computer by comparing the area of the first region to the area of the second region. If the area of the first region is less than the area of the second region, the system inputs a positive Z input. If the area of the first region is greater than the area of the second region, the system inputs a negative Z input. Preferably, a positive Z input is interpreted as a mouse button down input and a negative Z input is interpreted as a mouse button up input.
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Kovaks-Vajna Zsolt Miklos
Manaresi Nicolo'
Rambaldi Roberto
Tartagni Marco
Osorio Ricardo
Shalwala Bipin
STMicroelectronics S.r.l.
Thompson & Knight L.L.P.
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