Computer graphics processing and selective visual display system – Display peripheral interface input device – Touch panel
Reexamination Certificate
1999-08-02
2002-03-05
Luu, Matthew (Department: 2672)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Touch panel
Reexamination Certificate
active
06353434
ABSTRACT:
This application is based on an application No. 10-254355 filed in Japan, the content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a conversion device for converting coordinates input by a coordinate input device such as a touch panel, and especially relates to the improvement of a calibration technology with which the position of an image on a display is matched to a position detected at the time of an input operation using the touch panel.
(2) Description of the Prior Art
Recently, touch panels have been widely used as an input device of computers.
A touch panel is a kind of light-transparent two-dimensional coordinate input device. More specifically, a touch panel is composed of a transparent material and is provided on the surface of an image display such as a liquid crystal display. When the user depresses the touch panel with a pen or finger, the touch panel detects the two-dimensional coordinates (x,y) corresponding to the position that is depressed and informs the computer of the detected coordinates.
A touch panel transfers data to the device driver for the touch panel that is a program in the computer via the communication port of the computer.
The device driver for a touch panel converts the coordinates that have been detected by the touch panel in the two-dimensional coordinate system inherent for the touch panel into coordinates in the image-displaying two-dimensional coordinate system, and transfers the converted coordinates to the operating system (referred to as the “OS” in this specification). In addition, the device driver exercises control inherent for the touch panel.
Here, the image-displaying two-dimensional coordinate system is a coordinate system used in the OS running on the computer for displaying images on the display.
For instance, coordinates within the range that is displayed on the display in the image-displaying two-dimensional coordinate system are given by (P,Q) [0≦P≦65535,0≦Q≦65535]. Here, the “P” indicates a horizontal coordinate and the “Q” indicates a vertical coordinate.
On the other hand, two-dimensional coordinates in the touch-panel-inherent two-dimensional coordinate system are given by (X,Y) [0≦X≦1023,0≦Y≦1023]. In the coordinate system, the coordinates corresponding to the upper left corner of the touch panel provided on the display is (0,0), the upper right corner is (1023,0), and the lower left corner is (0, 1023).
The OS defines the interface for receiving coordinates from the coordinate input device such as a mouse and a touch panel, and the received coordinates are transferred to application programs running under the control of the OS. For instance, when the user depresses the touch panel by depressing an icon on the display with a finger, the same operation is to be executed on the computer as the user puts the cursor on the icon with a mouse and click the mouse on the icon.
Note that since the touch-panel-inherent two-dimensional coordinate system is different from the image-displaying two-dimensional coordinate system, the coordinates of an image on the display needs to be matched to coordinates input by the touch panel. For this purpose, calibration is performed. Calibration is performed using a dedicated control program and expressions for coordinate transformation are obtained in advance so that the touch-panel device driver converts two-dimensional coordinates that have been transmitted from the touch panel via the communication port into coordinates in the image-displaying two-dimensional coordinate system.
Here, an explanation of the process of the calibration by a conventional control program will be given.
The calibration process by the conventional control program is to specify Expressions 1 and 2 as coordinate transformation expressions for calculating two-dimensional coordinates (P,Q) in the image-displaying two-dimensional coordinate system from input coordinates (X,Y) in the touch-panel-inherent coordinate system. The Expressions 1 and 2 are given below.
P=aX+b
(Expression 1)
Q=cY+d
(Expression 2)
FIG. 1
is a flowchart illustrating the conventional calibration processing according to a control program.
The control program notifies the touch-panel device driver of the start of the calibration processing (step S
901
). After the notification, the touch-panel device driver informs the OS of coordinates that have been transmitted from the touch panel in the touch-panel-inherent coordinate system without conversion until the notification of the end of the calibration processing. As a result, after the notification at step S
901
, the control program receives coordinates in the touch-panel-inherent coordinate system via the OS.
The control program displays a message that requests the user to depress a mark with a pen (step S
902
) and displays the image of the mark at coordinates (13106,13106) in the image-displaying two-dimensional coordinate system (step S
903
).
FIG. 2
shows a mark image displayed in the calibration process and how the user depresses the touch panel with a pen to indicate the mark.
As a result of step S
903
, an “X” mark is displayed at the upper left of the display screen on which a touch panel is provided as shown in a condition
921
.
Note that the upper left corner and the lower right corner of the display are supposed to be indicated as two-dimensional coordinates (0,0) and (65535,65535) in the image-displaying two-dimensional coordinate system respectively. The control program displays an image at any position on the display via the OS by transferring two-dimensional coordinates in the image-displaying two-dimensional coordinate system to the OS.
A condition
922
shows how the user depresses the touch panel with a pen to indicate the mark image.
When the user depresses the touch panel as shown in the condition
922
, the touch panel detects the depressed position and informs the touch-panel device driver of the detected position as the two-dimensional coordinates in the touch-panel-inherent coordinate system via the communication port.
The touch-panel device driver informs the OS of the coordinates transmitted from the touch panel as they are.
The control program obtains the co-ordinates via the OS that the user has depressed (step S
904
). The obtained coordinates are supposed to be coordinates (X
1
,Y
1
). At step S
904
, the process stops and awaits the obtainment of coordinates by the control program.
After obtaining the coordinates (X
1
,Y
1
), the control program displays another mark image at coordinates (52429,52429) in the image-displaying two-dimensional coordinate system (step S
905
).
After displaying the mark image, the control program obtains coordinates in the touch-panel-inherent coordinate system according to the depression of the touch panel by the user as at step S
904
(step S
906
). The coordinates obtained at step S
906
are supposed to be coordinates (X
2
,Y
2
) After obtaining the coordinates (X
2
,Y
2
), the control program substitutes coordinates (13106,13106) and (52429,52429) into the (P, Q) and coordinates (X
1
,Y
1
) and (X
2
,Y
2
) into the (X,Y) in Expressions 1 and 2, which each are coordinate transformation expressions, respectively to obtain coefficients “a”, “b”, “c”, and “d” in the Expressions 1 and 2 and records the coefficients in a file (step S
907
).
Here, the coefficients “a”, “b”, “c”, “f”, and “d” are calculated according to Expressions 3 to 6 given below.
a
=(52429−13106)/(
X
2
−X
1
) (Expression 3)
b
=13106
−X
1
(52429−13106)/(
X
2
−X
1
) (Expression 4)
c
=(52429−13106)/(
Y
2
−Y
1
) (Expression 5)
d=
13106−
Y
1
(52429−13106)/(
Y
2
−Y
1
) (Expression 6)
The file in which the coefficients “a”, “b”, “c”, and “d” are recorded is referred to by the touch-panel device driver at the start-up time of the OS. After that the touch-panel device d
Akebi Kazuhiko
Nishihara Shinya
Okabe Minoru
Gunze Limited
Luu Matthew
Price and Gess
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