KR100446610B1 - Pen-type computer input device - Google Patents

Abstract

The present invention relates to a pen-type computer input device, comprising: image pickup means for measuring a change in an image generated by movement of the pen-type computer input device, and three rotations for measuring a rotational angle caused by the movement of the pen-type computer input device. And a signal processing unit for detecting movement of the pen-type computer input device by using each sensor and the change in the image received from the image pickup means and the rotation value of the pen received from the rotation angle sensor. In this way, by mounting a rotation angle sensor for measuring the change in rotation angle, it is possible to measure the motion of the pen-type computer input device using only two corresponding points in the continuously acquired images.

Description

Pen-type computer input device

The present invention relates to a pen type computer input device, and more particularly, to a pen type computer input device using a CCD camera and a gyro sensor.

Existing methods for inputting a document include a method using rotation of a ball disclosed in US Pat. No. 5,027,115, a method for measuring a force acting on a pen disclosed in US Pat. No. 5,111,004, US Pat. Nos. 4,513,437 and 5,247,137. A method using an accelerometer and a gyro disclosed in, and a method using a CCD camera disclosed in US Pat. No. 6,031,936. However, most of the conventional methods have a problem in that it is difficult to measure the exact movement of the pen due to slipping errors or errors in pen force transmission.

In addition, as an existing input device using a camera, the method proposed by Anoto is the latest technology. This method has the advantage of using only a camera, but a disadvantage is that a special paper is coded for use.

On the other hand, the method of extracting the motion of the camera using the existing camera was possible only by solving the epipolar geometry. The following derives the general epipolar geometry formula.

3 shows the pen input device 30 in two positions. The coordinate system located at the center of the lens of the camera of the pen input device at the two positions is as follows.

,

The projection relationship to the coordinate system and the image is as follows.

,

The relationship between the cameras of the pen input devices at the two positions is expressed as follows.

Also, to simplify the above Equation 3, the following matrix is defined.

Is determined only by the rotation R and the parallel movement S between the two cameras.

here,

ego,

Is, If this is not permutation of (1,2,3), to be.

From this relationship, the following properties can be obtained.

From above Since is anti-symmetric, we get

From above, the relationship in the image is as follows.

Equation 8 is generally referred to as an "eight point problem" in the sense that eight correspondence points are needed to obtain the eight elements of the "epipolar equation" or Q. Several methods have been proposed to solve the epipolar equation by obtaining eight corresponding points from the epipolar equation. However, the conditions for the above eight points are very limited, so that the error in the result obtained can be large. In addition, the obtained Q includes elements of rotation and parallel movement, so the problem of separating them is not easy.

The present invention is to obtain a three-dimensional motion of the pen with only two corresponding points by mounting a sensor that can measure the change in rotation angle to solve the above problems.

1 is a diagram showing an example of a pen-type computer input device according to the present invention.

FIG. 2 shows in more detail the main configuration of the pen-type computer input device shown in FIG. 1; FIG.

3 shows a pen-type computer input device in two positions.

One feature of the present invention for solving the above problems is that the pen-type computer input device, the image pickup means for measuring the change in the image generated in accordance with the movement of the pen-type computer input device, and the pen-type computer input device Signal for detecting the motion of the pen-type computer input device using three rotation angle sensors for measuring the rotation angle by the movement, the change of the image received from the image pickup means, and the rotation value of the pen received from the rotation angle sensor. It includes a processing unit.

Preferably, the rotation angle sensor is a three-axis speed gyro sensor for detecting the rotation speed of the pen-type computer input device and calculating the rotation angle from the detected rotation speed.

Also preferably, the image pickup means is a CCD array.

Also, preferably, the change in the rigid image is a coordinate of two points extracted from two images obtained continuously according to the movement of the pen.

Another aspect of the present invention relates to a method for measuring a motion of a data input pen, the method comprising: obtaining two images in succession in accordance with the movement of the data input pen, and rotating three axes in accordance with the movement of the data input pen. Obtaining an angle, and calculating a motion of a data input pen using the three-axis rotation angle and the two images.

Preferably, the pen movement calculation step includes obtaining coordinates of two corresponding points from the two images, and calculating a pen movement using the three-axis rotation angle and the coordinates of the two points. It is characterized by.

Hereinafter, the present invention will be described in detail with reference to FIGS.

1 shows an example of a pen-type computer input device 10 according to the present invention. The pen-type computer input device 10 is equipped with an electrical circuit such as a pen stylus 11, a lens 12, a lens system 13, a CCD array 14 as an image pickup means, an LSI chip, and the like in a pen-type housing unit 20. A signal processor 15 including a printed circuit board, a storage unit 17 such as a random access memory, a power supply unit 18 such as a battery, and a communication unit 19.

The lens 12 is located at the extreme end of the lens system 12 for guiding the image from the outside to the CCD and the pen stylus 11 is located at the center of the lens. The CCD array 14 is connected so that the handwriting signal detected by the CCD array is input to the signal processor 15.

The signal processor 15 includes an analog / digital signal processing circuit, a microcontroller, and a memory chip that stores software for determining a pen position and transmitting data to a host computer.

The speed gyro sensor 16 detects the rotation speed of the pen-type computer input device 10, calculates the rotation angle from the detected rotation speed, and outputs the rotation direction obtained by adding the rotation angle to the reference orientation. Such speed gyro sensors include conventional gyro sensors having gimbals, optical fiber gyros, and gas speed sensors.

The communication unit 19 includes an antenna or the like for transmitting data stored in the storage unit 18 to a host computer.

FIG. 2 shows the main configuration of the pen-type computer input device 10 shown in FIG. 1 in more detail.

The signal processor 15 receives the position data about the two corresponding points input through the lens 12, the lens system 13, the CCD array 14 and the rotation angle data input from the speed gyro sensor 16, The three-dimensional motion of the pen is calculated, and the data about the three-dimensional motion of the pen is output to the storage unit 18. The communication unit 19 receives data about the movement of the pen stored in the storage unit 18 and transmits it to the host computer.

The principle and process of calculating the three-dimensional motion of the pen using the data input from the CCD array 14 and the speed gyro sensor 16 in the signal processor 15 will be described.

In the present invention, the rotation angle of the pen-type input device can be known by attaching three rotation angle sensors, that is, the speed gyro sensor 16, to the pen input device 10. Therefore, since the rotation value variable R can be known from Equation 4 regarding epipolar geometry, only the unknown value is the moving values T1, T2, and T3, and therefore only the positions of three corresponding points are needed. In practice, however, since the equation has a Trivial solution, it is generally possible to set T3 = 1 and obtain the values of T1 and T2 relative to this value. Therefore, if we know only two corresponding points, T1 and T2, we can get the three-dimensional motion of the pen.

By developing Equation 8 with respect to any one point Pi, the following equation can be obtained.

Equation (8) Expanded with respect to any other arbitrary point Pj, the following equation is obtained.

here, R is a known value since it can be obtained by three rotation angle sensors. μ and υ are images with temporal differences, and i and j are subscripts representing two different points in an image.

Equation 9 and Equation 10 obtained with respect to two arbitrary points Pi and Pj are arranged in a matrix form as follows.

From Equation 11 above, the signal processor 15 receives information about the position of the corresponding two points received from the CCD array 14, that is, the pen motion input from the T1, T2 and the speed gyro sensor 16. The three-dimensional motion of the pen may be calculated using the information R about the rotation speed, and a character, a picture, a symbol, a gesture, and the like, which the user wishes to input, may be input from the three-dimensional motion of the pen.

The present invention allows a natural input as if a user uses a general pen by using a camera and a rotation sensor mounted on a pen without limiting a special paper or pad. In addition, the present invention can be input in the space it is easy to use as an input device for presentation or other Internet TV.

Claims (7)

In a pen-type computer input device, Image pickup means for measuring the coordinates of one point and the coordinates of the corresponding point from two images obtained successively according to the movement of the pen-type computer input device; Three rotation angle sensors for measuring rotation angles caused by movement of the pen-type computer input device; And a signal processor for detecting a motion of the pen-type computer input device by using two coordinates received from the image pickup means and a rotation value of the pen received from the rotation angle sensor. The method of claim 1, And the rotation angle sensor is a three-axis speed gyro sensor for detecting the rotation speed of the pen-type computer input device and calculating the rotation angle from the detected rotation speed. The method of claim 1, And said image pickup means is a CCD array. delete The method of claim 1, A storage unit for storing data on the motion of the pen-type computer input device detected by the signal processor; The pen-type computer input device further comprises a communication unit for transmitting data on the movement of the pen-type computer input device stored in the storage unit by wireless communication. In the method of measuring the movement of the data input pen, Extracting coordinates of one point and coordinates of a corresponding point from two images obtained continuously according to the movement of the data input pen; Obtaining a three-axis rotation angle according to the movement of the data input pen; Calculating the motion of the data input pen using the three-axis rotation angle and the coordinates of the two points. delete