JP2001265517A - Coordinate input device, mounting method for sensor head, display device with coordinate input device and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a degree of freedom of a mounting position of a light receiving/emitting means on a coordinate input surface. SOLUTION: Light shielding position information (u11 to u51), (u12 to u52 and coordinates of reference points in sensor heads 1, 2 when an object is inserted into reference points (x1, y1) to (X5, y5) are stored in first storage parts 3, 4. Coefficient calculating means 5, 6 calculate coefficients (c11 to c51), (c12 to c52) by every sensor head on the basis of the coordinates of the reference points and the light shielding position information and stores them in second storage parts 7, 8. A prescribed operation 9 is performed by using pieces of information u1, u2 corresponding to shielding positions of light generated in each of the sensor heads 1, 2 by the light shielding object inserted in the case of input of the coordinates and the coefficients stored in the second storage parts 2 by and a coordinate (x, y) into which the light shielding object is inserted is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device, and more particularly to a so-called touch panel for inputting a coordinate position indicated by a pointing member such as a pen or a finger to input or select information in a personal computer or the like. The present invention relates to a coordinate input device. This coordinate input device is used integrally with an electronic blackboard and a large display, and is not limited to a form integrated with an electronic display device, such as a wall surface, a paper surface on a desk, or a conventional blackboard, but is written there. Used for devices that digitize information.

[0002]

2. Description of the Related Art FIG. 18 is a diagram showing a configuration of an optical coordinate input device to which the present invention is applied. The optical coordinate input device 40 includes a light emitting / receiving means 41, a coordinate input area 43, and a retroreflective member 44. Coordinate input area 43
Is a quadrangular shape. For example, a coordinate input area is a display surface for electronically displaying characters or images, a whiteboard written with a pen such as a marker, or the like.

[0003] The optical coordinate input device 40 includes a user's hand made of an optically opaque material on the coordinate input area 43.
This device detects the coordinate position of the pointing object 42 when touched by the pointing object 42 such as a finger, a pen, or a support rod, and inputs the position information to a personal computer or the like.

[0004] At both upper ends of the coordinate input area 43, light receiving / emitting means 41 are provided. From the light receiving / emitting means 41 toward the coordinate input area 43, L ₁ , L ₂ , L ₃ ,. . . L _m of the light beam bundle (probe light) is irradiated. Actually, it is a fan-shaped plate-like light wave that spreads from the point light source 61 and travels in parallel to the plane of the coordinate input area.

[0005] Also, in the peripheral portion of the coordinate input area 43,
A retroreflective member 44 is provided with the retroreflective surface facing the center of the coordinate input area 43. The retroreflective member 44 is
It is a member having the property of reflecting incident light in the same direction regardless of the angle of incidence. For example, when focusing on a certain beam 47 out of the fan-shaped plate-like light waves emitted from the light emitting / receiving means 41, the beam 47 is reflected by the retroreflecting member 44, and the same light path is again returned as the retroreflected light 46 as the light receiving / emitting means Proceed back to 41. Light receiving and emitting means 41
Is provided with a light receiving means, as will be described later, and can detect whether or not the return light of each of the probe lights L _{1 to} L _m has returned to the light receiving / emitting means 41.

Now, consider the case where the user touches the position 42 with his hand. At this time, the probe light 45 is blocked by the hand at the position 42 and does not reach the retroreflective member 44. Therefore, the return light of the probe light 45 does not reach the light receiving / emitting means 41,
By detecting that the return light corresponding to the probe light 45 is not received, it is possible to detect that the pointing object is inserted on the extension line (straight line L) of the probe light 45.

Similarly, the probe light is emitted from the light receiving / emitting means 41 provided at the upper right of FIG. 18 and the extension of the probe light 48 is detected by detecting that the return light corresponding to the probe light 48 is not received. It is possible to detect that the pointing object has been inserted on (straight line R). If the straight line L and the straight line R can be obtained, the coordinates of the intersection where the pointing object 42 such as a hand is inserted can be obtained by calculating the intersection coordinates by calculation.

Next, the configuration of the light emitting / receiving means 41 and a mechanism for detecting which probe light among the probe lights L _{1 to} L _m has been blocked will be described. FIG.
2 shows the internal configuration of FIG. FIG. 19 is a diagram of the light emitting / receiving unit 41 attached to the coordinate input area 43 of FIG. 18 as viewed from a direction perpendicular to the plane of the coordinate input area 43. Here, for simplicity, a two-dimensional plane parallel to the plane of the coordinate input area 43 will be described.

The light receiving / emitting means 41 comprises a point light source 61, a condenser lens 51 and a light receiving element 50. The point light source 61 emits light in a fan shape in a direction opposite to the light receiving element 50 when viewed from the light source. The fan-shaped light emitted from the point light source 61 is considered to be a set of beams traveling in the directions of arrows 53 and 58 and other directions. The beam traveling in the direction of the arrow 53 is reflected by the retroreflective member 55, and the retroreflected light 54 passes through the condenser lens 51 and reaches a position 57 on the light receiving element 50.

The beam traveling in the traveling direction 58 is reflected by the retroreflective member 55, and the retroreflected light 59 reaches a position 56 on the light receiving element 50. The light emitted from the point light source 61 and reflected by the retroreflective member 55 and returning on the same path reaches the different positions 56 and 57 on the light receiving element 50 by the action of the condenser lens 51, respectively. .

Accordingly, the pointing object is inserted at a certain position,
When a certain beam is cut off, light does not reach a point on the light receiving element 50 corresponding to the beam. From this,
By examining the distribution of light intensity on the light receiving element 50,
You can see which beam was blocked.

FIG. 20 is a diagram for explaining the operation when the pointing object is inserted and the beam is cut off. In FIG. 20, the light receiving element 50 is provided on the focal plane of the condenser lens 51. Light emitted from the point light source 61 toward the right side in FIG. 20 is reflected by the retroreflective member 55 and returns along the same path. Therefore, the light is condensed again at the position of the point light source 61. The center of the condenser lens 51 is provided so as to coincide with the point light source position. Retroreflective member or 55
Since the returning light from the lens passes through the center of the condenser lens 51, it travels in a symmetrical path behind the lens (on the light receiving element side).

At this time, when the light intensity distribution on the light receiving element 50 is examined, if the pointing object 60 is not inserted, the light intensity distribution on the light receiving element 50 is almost constant, but as shown in FIG. When the pointing object 60 that blocks light is inserted,
Blocked the beam passing therethrough, the position of the position D _n is on the light receiving element 50, the light intensity is weak area (dark spot) occurs.

This position D _n is determined by the emission /
And corresponds to the incident angle theta _n, theta by detecting the D _n
n can be calculated. That theta _n can be represented as theta _n = arctan as a function of D _n (D _n / f) Equation (1). Here, f is the distance between the condenser lens 51 and the light receiving element 50, as shown in FIG. 20, and corresponds to the focal length of the condenser lens 51.

[0015] replacing Here, especially theta a _n theta _nL in the light receiving and emitting unit 41 in the upper left side of FIG. 18, the D _n and D _nL. Further, in FIG. 21 for explaining the method of calculating the coordinate position, the pointing object 60 and the coordinate input area 4 are converted by the conversion g of the geometric relative positional relationship between the light emitting / receiving means 41 and the coordinate input area 43.
Angle theta _L of the x-axis of 3, D _nL obtained by the formula (1)
Θ _L = g (θ _nL ) where θ _nL = arctan (D _nL / f).

Similarly, the light receiving / emitting means 41 at the upper right of FIG.
Is also replaced by the R symbol in the above equation, and the conversion h of the geometric relative positional relationship between the light emitting / receiving means 41 and the coordinate input area 43 on the right side gives θ _R = h (θ _nR ). θ _nR = arctan (D _nR / f) Equation (3) can be expressed.

As shown in FIG. 21, in the coordinate input area 43, the mounting interval of the light receiving / emitting means 41 is set to w, the left corner of the coordinate input area 43 is set to the origin 70, and the x and y coordinates are set to FIG.
The pointing object 6 on the coordinate input area 43
The coordinates (x, y) of the point designated by 0 are as follows: x = wtan θ _R / (tan θ _L + tan θ _R ) Expression (4) y = wt tan θ _L · tan θ _R / (tan θ _L + tan θ _R ) Expression (5) X, y from (2), (3), (4), (5)
Can be expressed as a function of D _nL , D _nR .

That is, by detecting the positions D _nL and D _nR of the dark spots on the light receiving elements 50 of the left and right light emitting / receiving means 41 and considering the geometrical arrangement of the light receiving / emitting means 41, the pointing object 6 is detected.
The coordinates of the point designated by 0 can be calculated. The above-described coordinate calculation method is based on the principle of triangulation and is described in, for example, Japanese Patent Application Laid-Open No. 9-91094.

[0019]

In the above-mentioned conventional coordinate input device, the coordinates are calculated based on the geometric arrangement of the light receiving and emitting means. Therefore, the coordinates of the coordinate input area can be obtained when the following parameters representing the geometrical arrangement are known. The above-mentioned "light receiving / emitting means" is referred to as "sensor head" in the following description.

FIG. 22 is a diagram showing an example in which the sensor head is arranged near the coordinate input area. In this figure, the coordinates x and y obtained from the equations (2) to (5) are coordinates having the point P as the origin. At the stage of calculating these coordinates, it is necessary that the angles θ _offL and θ _offR formed by w and the line segment connecting the optical axes of the sensor heads L and R to the centers of the sensor heads are already known. θ _offL and θ _offR are parameters necessary for the conversion of g and h in equations (2) and (3), respectively.

Further, since the offsets dx and dy due to the parallel movement and the offset θ ₀ due to the rotation in the coordinate system having the origins P and Q are known, the P obtained from the equations (2) to (5) can be used as the origin. Coordinates x,
y can be converted to a coordinate system with Q as the origin of the coordinate input area. Therefore, w, θ _offL , θ _offR , d
It is necessary to determine the mechanical position of the sensor head so that x, dy, θ ₀ are known.

However, in general, assembling the sensor head so that all of these parameters have predetermined values increases the cost in the apparatus manufacturing process. Also,
Assemble these parameters within a tight tolerance, measure these parameters after assembly,
There is also a method of reflecting it in the calculation. However, this method is not practical because it involves difficulty in measuring parameters after assembly.

In addition, there is a problem that the above parameters are deviated from the set values at the time of shipment due to vibration during transportation and the like, and a correct coordinate input operation cannot be performed at the time of delivery. Further, even when the light emitting / receiving device is divided and transported for transportation and packing, the light emitting / receiving device is moved to a coordinate input surface (display surface, blackboard surface, etc.) while maintaining a predetermined positional accuracy at the time of assembly. Need to be re-attached.

However, it is difficult for a general user to re-attach while maintaining accuracy, or special jigs and mechanisms are required, which increases costs. In addition to this, for example, when an application is considered in which the sensor head portion formed by the light receiving and emitting means is divided into a portable type and the user attaches it to an arbitrary coordinate input surface and is used, a conventional triangulation calculation method is similar. Problems arise and are difficult to implement.

The present invention has been made in view of the problems of the coordinate input device as described above.
It is an object of the present invention to provide a coordinate input device and a sensor head mounting method in which the degree of freedom of the mounting position of the light receiving / emitting means on the coordinate input surface is increased.

Another object of the present invention is to provide a simple calibration operation before use to correctly input coordinates on the coordinate input surface even when the mounting position of the light emitting / receiving means on the coordinate input surface, ie, when the above-mentioned parameters are unknown. It is an object of the present invention to provide a coordinate input device capable of performing such operations.

Another object of the present invention is to provide a coordinate input device for performing calibration which can be executed by simple matrix calculation or solution of simultaneous equations.

Another object of the present invention is to provide information corresponding to the position of light blocked by the light blocking means inserted at a predetermined coordinate for performing calibration, on a geometric position on the light receiving element, Alternatively, the calculation can be performed by an arbitrary signal such as a timing signal for scanning the light receiving element, and the process of converting the position of the blocked light into the expected angle of the blocking unit can be omitted, thereby greatly improving the efficiency of the calculation. Along with
An object of the present invention is to provide a coordinate input device that improves the degree of freedom in designing the device and improves the accuracy of coordinate calculation.

Another object of the present invention is to use a physical position on a light receiving element as information corresponding to a light blocking position, thereby eliminating the need for a process of creating a conversion table or a conversion formula. Error factors generated in the creation process can be eliminated, and furthermore, as a signal corresponding to the position of the blocked light on the light receiving element, in addition to the physical position on the light receiving element, electrical scanning of the light receiving element Another object of the present invention is to provide a coordinate input device that can perform calculations using other physical quantities such as the timing signal described above, and that greatly improves the degree of freedom in design.

Another object of the present invention is to calculate a coefficient of a relational expression describing a relationship between predetermined coordinates at which the light blocking means is inserted at the time of calibration and corresponding positional information of the blocked light. , As a condition that the coefficient can always be calculated,
Since the coefficient matrix of the simultaneous equations must always be regular, a coordinate input device and a sensor head mounting method are provided in which the coefficient matrix is always regular by limiting the number of reference coordinate points and the arrangement method. Is to do.

Another object of the present invention is to provide a display device with a coordinate input device which has a simple structure and can input coordinates with high accuracy.

Still another object of the present invention is to provide a calibration mode and a coordinate input mode so that the user can arbitrarily switch modes when the position of the light receiving / emitting means is shifted during use or immediately after transportation. An object of the present invention is to provide a coordinate input device and a recording medium which can be calibrated by a user himself.

[0033]

According to the present invention, the light blocking position information and the reference point are set based on the light blocking position information and the reference point coordinates of the sensor head when the pointing object is inserted into the reference point during calibration. Calculate the coefficients of the relational expression describing the relation with the coordinates. The light-blocking object inserted at the time of inputting coordinates is used to perform a predetermined calculation using the information corresponding to the light-blocking position of light generated in each sensor head and the previously calculated coefficient, thereby inserting the light-blocking object. Output coordinates.

In the present invention, a physical position obtained from the light intensity distribution on the image plane of the light receiving means is used as the light blocking position information.

Further, according to the present invention, when calculating the coefficients at the time of calibration, the coefficient matrix needs to be regular, so that the number of reference coordinates is set to 5 and the coordinates of these 5 points are determined by the light receiving means. They are arranged so that straight lines connecting the center and the coordinates of each point do not coincide with each other.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to the drawings. (Embodiment 1) FIG. 1 shows the configuration of Embodiment 1 of the present invention.
FIG. 2 is a processing flowchart according to the first embodiment of the present invention. This embodiment is applied to the optical coordinate input device of the retroreflective projection system described with reference to FIGS. Example 2
The two sensor heads 1 and 2 are arranged near the outside of the coordinate input area 43 as described with reference to FIG. Also,
The coordinates of the reference point for calibration are known coordinates on the coordinate input area, and are represented by (x ₁ , y ₁ ), (x
_2, y _2). . . (X ₅ , y ₅ ) (Step 10
1).

Each of the reference points (x ₁ , y ₁ ), (x ₂ ,
y ₂ ). . . The (x _5, y _5), the pointing object that blocks light fingers are inserted. For example, when a finger is inserted at the reference point (x ₁ , y ₁ ), information corresponding to the light blocking position (A in FIG. 20) of the sensor head 1 caused by the probe light being blocked by the finger is represented by u _11. And Likewise the blocking position of the light beam in the sensor head 2 and u ₁₂ (Step 10
2).

The first subscript of u corresponds to the subscript of the reference point,
The second subscript corresponds to the number of the sensor head. As u, information corresponding to the light blocking position shown in FIG. 20 is used. For example, when the light receiving element 50 is a CCD in FIG. 20, as will be described later, u can be a pixel suffix (pixel position number) of the CCD corresponding to the light blocking position, or the like. u may be the timing of a signal for scanning the CCD, that is, the time from the start of scanning the CCD to the light blocking position, in addition to the pixel subscript. In addition, these may have a predetermined coefficient or offset, and parameters convenient for the design of the apparatus can be arbitrarily used.

Reference points (x ₁ , y ₁ ), (x ₂ , y ₂ ). . .
(X ₅ , y ₅ )
Light blocking position information (u ₁₁ , u ₂₁ ,..., U ₅₁ ) and (u ₁₂ , u ₁₂ ) in the sensor heads 1 and 2
_22,. . . , U ₅₂ ) and the coordinates of the reference point are stored in the first storage units 3 and 4, respectively (step 103).

The reference point coordinates and the light shielding position information stored in the first storage units 3 and 4 are read into the coefficient calculation units 5 and 6. The coefficient calculating means 5 and 6 calculate the coefficient (c ₁₁ ,
c ₂₁ ,. . . , C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C
₅₂ ) is calculated (step 104) and stored in the second storage units 7 and 8 (step 105).

The operation up to this point is the calibration operation mode, which is indicated by thick arrows in FIG. These series of operations are performed before the user uses the coordinate input device or when the user installs the coordinate input device.

Following the calibration operation mode,
This is an operation mode for inputting coordinates. Hereinafter, the coordinate input operation will be described.

Light is blocked in each of the sensor heads 1 and 2 by a light blocking object such as a finger inserted in the coordinate input area.
That is, in the same manner as described in the calibration mode, the information u ₁ and u ₂ corresponding to the light blocking position are acquired by the sensor heads 1 and 2 (step 106).

Further, the coefficients (c) stored in the second storage units 7 and 8 in the above-described calibration operation mode
₁₁ , c21 _,. . . , C ₅₁ ) and (c ₁₂ ,
c ₂₂ ,. . . , C ₅₂ ) is read out (step 10).
7), the coordinate calculator 9 calculates u ₁ , u ₂ and (c ₁₁ ,
c ₂₁ ,. . . , C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C
_The coordinates (x, y) at which the light-blocking object such as a finger is inserted are output to a personal computer (not shown) or the like (step 109).

In the processing flowchart of FIG. 2, for example, the calibration operation mode on the sensor head 1 side (steps 101 to 105) and the calibration operation mode on the sensor head 2 side (steps 101 to 1)
05) are performed in parallel, and then the coordinate calculation mode (steps 106 to 109) is executed. The calibration operation mode of the sensor head 1 is executed, and then the calibration operation mode of the sensor head 2 is executed. And then execute the coordinate calculation mode.

Hereinafter, the calculation of the coefficients and the calculation of the coordinates will be described in detail. In general, a camera system shoots an object in a three-dimensional space and records the image on a two-dimensional film surface. FIG. 3 is a diagram illustrating the concept of a camera system.
(X, y, z) is the object space coordinates, and p (x, y, z) is the position of the object. (U, v) is the image space coordinates,
This is a coordinate system representing the position of the image on the image plane. The point r is the principal point position of the lens. The point p in the three-dimensional object space is converted into a point q in the two-dimensional image space by a mapping f via a lens. Ie

(Equation 5) If the mapping f at this time can be estimated, the position of the object in the three-dimensional object space can be estimated from the position of the image on the two-dimensional film surface by using the inverse mapping of the mapping f.

In general, the mapping f is represented by Expressions (6) and (7) (for example, see Xu Jiang, 3D Vision, p79, Kyoritsu Shuppan, 1998).

[0048]

(Equation 6)

(Equation 7)

Here, a coordinate input system in the above-described optical coordinate input device to which the present invention is applied will be considered. In this coordinate system, the object space is two-dimensional, and the image space is one-dimensional. That is, the object space is a coordinate input area and is constrained on a plane. The image space is one-dimensional CC
D and is constrained on a straight line along the array of CCD pixels.

That is, for the general formulas (6) and (7), it is assumed that the u axis in the image space is in the same plane as the xy plane in the object space. Therefore, Expressions (6) and (7) are expressed as Expression (8) by rewriting the coefficients c ₄ , c ₉ , and c ₁₀ as c ₃ , c ₄ , and c _5. 9) is obtained.

(Equation 8) c ₁ x + c ₂ y + c ₃ −c ₄ ux−c ₅ uu = u Equation (9)

Equation (9) is obtained by calculating coordinates (x, y) on the coordinate input area where an object such as a finger is inserted, and a light blocking position on the light receiving element of the sensor head (information corresponding to the light blocking position). This is an expression relating u. Where c ₁ , c ₂ ,
c ₃ , c ₄ , and c ₅ are coefficients and exist for each sensor head. In the above-described calibration operation mode, this coefficient is determined for each sensor head.

Hereinafter, a method of determining these coefficients will be described.
The coefficients c _1n , c _{2n ,.} . . c
_5n is obtained as follows. That is, m known points p ₁ (x ₁ , y ₁ ), p ₂ (x ₂ , y ₂ ),. . . p
_m (x _m , y _m ) and the corresponding image positions q _1n (u _1n ), q _2n (u _2n ),. . .
For q _mn (u _mn ), the following simultaneous equations are obtained from equation (9).

(Equation 9) Since there are five unknown coefficients, m = 5 in equation (10), and the image plane position q corresponding to each of the five known points p
Ask for. In the coefficient calculation units 5 and 6 in FIG.
0), the coefficient vectors {c _1n , c _{2n ,.} . . c _5n } is calculated for each sensor head and stored in the second storage units 7 and 8.

[0053]

(Equation 10)

Next, a method of calculating coordinates in the coordinate input operation mode will be described. Let n be the number of sensor heads and the coefficients for each sensor head be c _1i , c _2i , c _3i ,
Let c _4i , c _5i (i = 1, 2,... n). Also, n
The image positions (measured values) of the sensor heads are u ₁ ,
u ₂ ,. . . u _n .

From the equation (9), the object space coordinates (coordinates on the coordinate input area) (x, y) satisfy the simultaneous equations of the equation (12).

[Equation 11] Therefore, the object coordinates (x, y) on the coordinate input area can be obtained by solving equation (12) and using equation (13).

[0056]

(Equation 12)

In the coordinate input device of the present invention, since the number of sensor heads is two, n = 2. The coordinate calculation unit 9 in FIG.
Then, according to equation (14), where n = 2 in equation (13), the coordinates (x, y) on the coordinate input surface where the pointing object such as a finger is inserted are calculated and output.

(Equation 13)

(Embodiment 2) In the prior art, as described above, the light receiving / emitting means of the light blocking means is based on the position (D _nL , D _nR ) of the light blocked by the light blocking means on the light receiving means. Needs to be converted to the expected angles from (θ _L , θ _R ),
It was necessary to obtain a conversion table or a conversion formula in advance.

On the other hand, in the present invention, by using other physical quantities such as a physical position on the light receiving element and a timing signal for electrical scanning of the light receiving element as information corresponding to the light blocking position, the apparatus design is improved. The degree of freedom has been greatly improved.

The second embodiment is an embodiment for detecting a light blocking position (hereinafter, a dip position). FIG. 4 shows the configuration of the second embodiment. The difference from the first embodiment is that dip position information detection units 10 and 11 are provided. The other components are the same as those in the first embodiment, and are applied to the optical coordinate input device of the retroreflective projection system as in the first embodiment. FIG.
9 is a processing flowchart according to the second embodiment. Step 202 in FIG. 5 corresponds to step 102 in FIG. 2, step 203 in FIG. 5 corresponds to step 103 in FIG. 2, and step 206 in FIG. 5 corresponds to step 106 in FIG. The light blocking position information of FIG. 2 is replaced with the dip position information of FIG.

That is, the reference points (x ₁ , y ₁ ), (x ₂ ,
y ₂ ). . . The dip position information (u ₁₁ , u ₂₁ ,...) Detected by the dip position information detectors 10 and 11 of the sensor head 1 and the sensor head 2 when the pointing object is inserted into (x ₅ , y ₅ ), respectively. , U ₅₁ ) and (u ₁₂ ,
u ₂₂ ,. . . , U ₅₂ ) and the coordinates of the reference point are stored in the first storage units 3 and 4, respectively (step 203).

The reference point coordinates and the dip position information stored in the first storage units 3 and 4 are read into coefficient calculation means 5 and 6, and the coefficients (c ₁₁ ,
c ₂₁ ,. . . , C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C
₅₂ ) is calculated (step 204) and stored in the second storage units 7 and 8 (step 205).

As in the first embodiment, the operation up to this point is the calibration operation mode, which is an operation executed before the user uses the coordinate input device or when installing the coordinate input device. . Subsequent to the calibration operation mode, the operation mode is for inputting coordinates.

A light blocking object such as a finger inserted into the coordinate input area causes a dip in each of the sensor heads 1 and 2 due to light blocking. The dip position information detectors 10 and 11 of the sensor head 1 and the sensor head 2 detect dip position information u ₁ and u ₂ corresponding to the light blocking position (step 206).

Further, in the above-described calibration operation mode, the coefficients (c
₁₁ , c21 _,. . . , C ₅₁ ) and (c ₁₂ ,
c ₂₂ ,. . . , C ₅₂ ) are read out (step 20).
7), the coordinate calculator 9 calculates u ₁ , u ₂ and (c ₁₁ ,
c ₂₁ ,. . . , C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C
₅₂ ) in the same manner as in the first embodiment (step 2).
08), coordinates (x, y) at which a light blocking object such as a finger is inserted
Is output (step 209).

In the dip position information detecting units 10 and 11,
For example, when the light receiving element 50 is a CCD in FIG. 20, the pixel subscript (that is, pixel position number) of the CCD corresponding to the light blocking position is used as the dip position information u.

FIG. 6 shows a pixel arrangement of the light receiving element. The light receiving element is a one-dimensional CCD 21, and FIG. 6 is an example of a CCD having 2048 pixels. In FIG. 6, the pixels 22 on the CCD are indexed from No. 0 to No. 2047. For example, when it is assumed that the dip position indicated by A is located at a pixel position with an index of 100 shown in FIG. 6, the dip position information or u in equation (8) is equal to that in FIG.
Of need not be expressed in physical size on the CCD plane with the origin at the center of the CCD corresponding to D _n, may be calculated by directly substituting the index number of 100 as u.

However, if the index is used when determining the coefficient, the index is also used during measurement, and if the actual physical size on the CCD whose origin is at the center of the CCD is used when determining the coefficient, the same applies when measuring. Use the actual size. Thus, it is necessary to use the same parameters at the time of coefficient determination and at the time of measurement. The above-mentioned index may be given a predetermined coefficient or offset, and any parameter convenient for the design of the apparatus can be arbitrarily used.

When using the above pixel index,
The pixel index can be obtained, for example, by the following method. That is, the light intensity distribution on the CCD at a certain time is read into an array corresponding to the CCD pixels. The same index as the pixel index is given to the array. For example, if the array is buf [0], buf
[1],. . . Assuming that buf [2047], the light intensity of the CCD pixel with the 100th index is stored in buf [100], and the light intensity of the CCD pixel with the 101st index is buf [101].
Is stored.

The dip position may be determined by software processing on the array storing the light intensities in this manner, for example, by a method described later, and the coordinates of the dip position array may be substituted for u to calculate the coordinates.

As another method of obtaining the index of the CCD pixel, a method of counting the CCD transfer clock can be used. FIG. 7 is a time chart showing a CCD transfer clock, a scan clock, and a sample / hold output of a photodiode arranged at a CCD pixel, that is, a CCD video output.

The transfer clock 23 is a clock for driving the CCD for transferring the charge of the photodiode of each pixel by the CCD. For simplicity, this example uses 1
Although only one transfer clock is shown, some elements actually require two clocks whose phases are inverted at a half of the illustrated period, and the operation of the illustrated clock is one example.

FIG. 8 shows a configuration for acquiring a CCD pixel index using a counter. The charge of each pixel is transferred by the CCD 21 every cycle of the transfer clock, sampled and held, and sequentially output to the output terminal. The scanning clock 24 is input to the CCD element by one pulse at the start of scanning for each scanning by the CCD. By counting the transfer clock 23 by the counter 26, it is possible to know at what pixel the charge has been output.

The transfer clock 23 is inputted to the CCD 21 and also to the input terminal of the counter 26. Further, the counter 26 is reset by the scanning clock 24. Accordingly, the output 27 of the counter 26 indicates the number of the pixel whose charge is currently being output since the CCD 21 started scanning. This counter output 27 corresponds to the above-described pixel index.

When the detection of the dip position is configured by hardware logic, it is convenient to use the counter output as the pixel index, because the circuit configuration is simplified. In the present invention, a convenient parameter can be arbitrarily used by a designer in designing a circuit or software.
It has a high degree of freedom in design and is particularly effective in reducing design man-hours and costs. FIG. 9 is a diagram illustrating a method of detecting a dip position in the dip position information detection unit.

The dip indicates the position of the dark spot due to light blocking in the light intensity distribution. FIG. 9 shows a waveform near the dip of the CCD sample hold output. The horizontal axis is a CCD pixel or an array stored corresponding to the CCD pixel. ui
Is an index corresponding to the CCD pixel as described above, such as an index of an array or a count value of a counter.

In the first method of detecting the dip position, CC
The D output value is sequentially scanned, and an index when a value smaller than a predetermined threshold value appears is defined as ui. The scanning is further continued, and the index of the output value immediately before the threshold value is again exceeded is set to ui + n. At this time, the dip position is calculated by equation (15).
Calculated according to

[Equation 14]

In the second method for detecting the dip position, the CC
D output values are sequentially scanned, and when a value smaller than a predetermined threshold value appears, the index is set to ui, ui + 1, ui +
2. . . ui + n. At this time, the dip position is calculated according to equation (16).

(Equation 15)

(Embodiment 3) Embodiment 3 is an embodiment relating to a method of arranging a sensor head. FIG. 10 shows a configuration in which the coordinate input device of the present invention is arranged on a display,
(A) is a plan view thereof, and (b) is a side view thereof.

A support case 33 is provided so as to be flush with the display surface 32 of the display 31, and the sensor heads 1 and 2 are arranged on the support case 33. Also,
A retroreflective plate 34 is also provided on the support housing 33.
The control unit including the coefficient calculation unit, the coordinate calculation unit, the storage unit, and the like is incorporated in, for example, the mechanical unit of the sensor head illustrated in FIG.

Points p1, p2, p in the coordinate input area 35
Reference numerals 3, p4 and p5 are the reference points for calibration described above whose coordinates are known. Point o is the center of one of the plurality of sensor heads. More precisely, it is the object-side principal point of the light receiving lens.

As described in the first embodiment, when the coefficients are calculated by equation (10), the coefficient matrix of the simultaneous equations must be regular as a condition that the coefficients can always be calculated. The coefficient matrix is made regular by setting five reference points for calibration and limiting the arrangement.

The sensor head is arranged on the support housing 33 as described below so as to satisfy the above conditions. That is, line segments op-p1, op-p2, 0-
so that p3, op4 and op5 do not all match,
The sensor head 2 and the reference point are arranged. Similarly, for the other sensor head 1, the reference point and the sensor head are arranged such that all the line segments connecting the principal point of the light receiving lens and the reference point do not coincide with each other.

FIG. 11 is a diagram showing an example of a sensor head mounting mechanism. A not-shown protrusion of the sensor head is inserted into the reference hole 36 and the long hole 37 of the support housing 33. Then, as described above, the center of the sensor head and each point p1 to p1
The direction of the sensor head is adjusted so that all the segments connecting p5 do not match, and the adjusted position is stopped with a screw or the like.

FIG. 12 is a view showing another example of a sensor head mounting mechanism. The sensor head of FIG. 12 is of a detachable type, and the sensor head is provided with detachable means 3 such as a suction cup.
8 attaches to the support housing 33. The method of mounting the sensor head in this example is the same as that described with reference to FIG. Further, the coordinate input device of the present invention may be installed on a screen surface on which a projector is projected, for example, in addition to the display described above.

(Embodiment 4) Embodiment 4 relates to a method of displaying a reference point for calibration. FIG.
FIG. 3 is a diagram illustrating a method of displaying a reference point when the coordinate input device of the present invention is installed on, for example, an electronic display.

These reference points are displayed as predetermined marks on the display only during the calibration operation. Alternatively, a reference point is marked on the display surface 32.

FIG. 14 is a diagram for explaining another example of a method of displaying a reference point. In FIG. 14, a reference chart 39 on which reference points are printed is stuck on the display surface 32.
Since the reference chart 39 is unnecessary at the time of inputting coordinates, it is removed from the display surface 32.

The above-described display method can be similarly applied to a case where the coordinate input device of the present invention is installed on a screen on which a projector is projected.

(Embodiment 5) Embodiment 5 is an embodiment in which the calibration mode and the coordinate input mode are switched. That is, when the position of the sensor head (light receiving / emitting means) is shifted during use of the coordinate input device, or immediately after transportation, the user can switch the mode arbitrarily and perform calibration by himself / herself. This is an example.

FIG. 15 shows the structure of the fifth embodiment. The difference from the first embodiment is that the switching means 12 to switch the operation state
17 is provided. These switching means 12 to 17
Operate in conjunction with each other in accordance with an instruction from the operation state instruction means 18. When the switching means 12 to 17 are in the state shown in the figure, the apparatus is in the calibration operation mode. When the switching means 12 to 17 are switched, the mode is the coordinate input operation mode. As the operation state instructing means 18, for example, a method of instructing the switching means from a user or the like is adopted.

FIG. 16 is a processing flowchart according to the fifth embodiment. Start 1 indicates the starting point of each calibration operation mode of the two sensor heads. Start 2 indicates the starting point of the normal coordinate input operation mode.

Start indicates the starting point of the process. It is assumed that the normal coordinate input operation mode is executed after the coefficient writing operation to the second storage units 7 and 8 is performed at least once in the calibration operation mode.

After the processing is started at the start, it is determined whether the operation mode is the calibration operation mode or the normal coordinate input mode (step 301). This is performed, for example, by the user determining the state of the switching units 12 to 17. Alternatively, a method of making a determination by referring to flags corresponding to the states of the switching units 12 to 17 can be adopted.

If it is determined that the operation mode is the calibration operation mode, the operation enters a start 1 and performs a calibration operation (steps 302 to 306). Otherwise, the operation enters a start 2 and a normal coordinate input operation is performed. (Steps 307 to 310). When one operation of each operation is completed, the operation returns to the start again, determines whether or not the operation is in the calibration mode, and performs the same operation.

(Embodiment 6) Embodiment 6 is an embodiment in which the present invention is realized by software, and FIG. 17 shows an example of the system configuration. In the system configuration, the coordinate input unit 80 includes, for example, the sensor head shown in FIG. The CPU 81 calculates the coefficients by executing the processing steps and processing functions of the above-described embodiment during the calibration operation, and calculates the coordinates by executing the processing steps and processing functions of the above-described embodiment when inputting the coordinates, For example, drawing data is generated from the input coordinate data, and characters and the like are displayed on the display device 83.

The program for executing the above processing is C
The program recorded on a recording medium such as the D-ROM 85 is read from the CD-ROM device 84 and installed in the system to be executed, thereby realizing the processing functions described in the above embodiments. In addition to the medium, the program described above includes a communication device 86,
It is also provided by downloading from a server or the like via the network 87.

The case where the present invention is applied to the retroreflective projection method has been described above, but the present invention is not limited to this.
The coordinate input surface is scanned by a sensor head (FIG. 23) employing an imaging method or a polygon mirror, the beam reflected by the retroreflective sheet is detected by a photodetector (PD), and the coordinate input surface is blocked by a finger or the like. In the case where the beam is interrupted by the above method, the beam corresponding to that point is not detected by the PD, and the position corresponding to the undetected beam is calculated by triangulation.
No. 0116).

[0099]

As described above, according to the first aspect of the present invention, if the parameter relating to the mounting position of the light receiving / emitting means on the coordinate input surface is unknown or is known at the time of mounting, the parameter may be unknown for some reason. Even if is changed, the coordinates on the coordinate input surface can be correctly input by a simple calibration operation before using the device, so that the reliability and convenience are improved.

According to the second aspect of the present invention, since the coefficient calculation and the coordinate calculation can be executed by simple matrix calculation or solution of simultaneous equations, the calculation function is mounted on the firmware of the coordinate input device. Or an external control device such as a personal computer for controlling the coordinate input device.

According to the third aspect of the present invention, since the physical position of the light receiving surface corresponding to the light blocking position is used as the optical position information in the light receiving means, it is necessary for the conventional triangulation method. A process for creating a simple conversion table or conversion formula can be omitted. Therefore, the conversion error generated in this processing is eliminated, and the coordinate calculation accuracy is significantly improved.

According to the fourth aspect of the present invention, the position calculated from the light intensity distribution on the light receiving surface corresponding to the light blocking position is used as the physical position of the light receiving surface corresponding to the light blocking position. Therefore, it is possible to greatly improve the efficiency of the calculation and improve the degree of freedom in designing the device.

According to the fifth aspect of the present invention, when the light receiving means is constituted by a CCD, the pixel number of the CCD corresponding to the light blocking position is used as the optical position information. Can be greatly improved.

According to the sixth aspect of the present invention, by limiting the way of arranging the coordinates of the five points, the coefficient matrix of the simultaneous equations is always regular, so that the solution is always obtained at the time of matrix calculation at the time of calibration. Processing errors are avoided and system stability is ensured.

According to the seventh aspect of the present invention, the degree of freedom of the mounting position of the sensor head (light receiving / emitting means) on the coordinate input surface can be increased, and the convenience of the device can be improved.

According to the eighth aspect of the present invention, the user can attach / detach the sensor head (light emitting / receiving means) as needed, so that when the position of the light emitting / receiving means is shifted during use,
Calibration can be performed by the user himself / herself immediately after transportation, and thus maintenance can be easily performed.

According to the ninth aspect of the present invention, when the coordinate input device is installed on the display device, the coordinate position can be input with high accuracy without requiring high mechanical accuracy.

According to the tenth aspect, the reference five points are displayed or engraved on the display surface, so that the user can easily perform calibration.

According to the eleventh aspect of the present invention, since a chart printed with reference points is used, calibration can be performed at low cost.

According to the twelfth aspect of the present invention, a predetermined coordinate on a two-dimensional coordinate space is calculated by using a function of converting a two-dimensional coordinate space into a one-dimensional image space according to a predetermined conversion formula. Therefore, the present invention can be applied to a coordinate input device employing various methods, and can provide a recording medium on which a highly versatile program is recorded.

According to the thirteenth aspect, since the calibration mode and the coordinate input mode are provided,
The mode can be freely switched to execute a program in any mode.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a processing flowchart according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating the concept of a camera system.

FIG. 4 is a diagram illustrating a configuration of a second exemplary embodiment of the present invention.

FIG. 5 is a processing flowchart according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a pixel array of a light receiving element.

FIG. 7: CCD transfer clock, scan clock and CC
5 is a time chart showing a sample hold output of a photodiode arranged in a D pixel, that is, a CCD video output.

FIG. 8 is a diagram showing a configuration for acquiring a CCD pixel index using a counter.

FIG. 9 is a diagram illustrating a method of detecting a dip position in a dip position information detection unit.

10A and 10B show a configuration in which the coordinate input device of the present invention is arranged on a display, FIG. 10A is a plan view thereof, and FIG.
Is a side view thereof.

FIG. 11 is a diagram illustrating an example of a sensor head mounting mechanism.

FIG. 12 is a diagram showing another example of a sensor head mounting mechanism.

FIG. 13 is a diagram illustrating a method of displaying a reference point when the coordinate input device of the present invention is installed on, for example, an electronic display.

FIG. 14 is a diagram illustrating another example of a method of displaying a reference point.

FIG. 15 is a diagram showing a configuration of a fifth embodiment of the present invention.

FIG. 16 is a processing flowchart according to a fifth embodiment of the present invention.

FIG. 17 is a diagram showing a configuration of a sixth embodiment of the present invention.

FIG. 18 is a diagram showing a configuration of an optical coordinate input device to which the present invention is applied.

19 is a diagram showing an internal configuration of the light emitting / receiving means of FIG. 18;

FIG. 20 is a diagram illustrating an operation when the pointing object is inserted and the beam is cut off.

FIG. 21 is a diagram illustrating a method of calculating a coordinate position based on the principle of triangulation.

FIG. 22 is a diagram showing an example in which a sensor head is arranged near a coordinate input area.

FIG. 23 is a diagram showing a sensor head employing an imaging method.

[Explanation of symbols]

 1, 2 Sensor head 3, 4 First storage unit 5, 6 Coefficient calculation unit 7, 8 Second storage unit 9 Coordinate calculation unit 10, 11 Dip position information detection unit 12-17 Switching means 18 Operating state instruction means 21, 50 Light receiving element 22 Pixel 23 Transfer clock 24 Scan clock 25 Photodiode sample hold output 26 Counter 27 Counter output 31 Display 32 Display surface 33 Support housing 34 Retroreflective plate 35, 43 Coordinate input area 36 Reference hole 37 Slot 38 Attachment / detachment means 39 Reference point chart 40 Coordinate input device 41 Light emitting / receiving means 42 Hand position 44, 55 Retroreflective member 45, 48 Probe light 46, 54, 59 Retroreflective light 47, 53, 58 Beam 51 Condensing lens 56, 57 Light receiving position 60 pointing object 61 point light source 62 imaging means 70 origin 80 coordinate input Unit 81 CPU 82 memory 83 display device 84 CD-ROM device 85 CD-ROM 86 communication device 87 network

Claims (13)

[Claims] 1. A plurality of light emitting means, a reflecting means for reflecting light emitted from the light emitting means toward the light emitting means, and a plurality of light receiving means for receiving light reflected by the reflecting means. A coordinate at which the light blocking means is inserted when the light path is blocked by inserting a predetermined light blocking means into the input area in an input area formed by the light path of the emitted light and the reflected light. A coordinate input device for calculating and inputting a position, wherein a relationship between a predetermined coordinate position in which the light blocking unit is inserted and optical position information in the plurality of light receiving units corresponding to the predetermined coordinate position. Are associated by a predetermined relational expression, based on a plurality of specific coordinate positions where the light blocking means is inserted, and optical position information in the plurality of light receiving means corresponding to the specific coordinate positions, Previous Coefficient calculating means for calculating a predetermined coefficient that satisfies the relational expression; and using the predetermined coordinate position by using optical position information and the predetermined coefficient in the plurality of light receiving units corresponding to the predetermined coordinate position. And a calculating means for calculating by a predetermined calculation. 2. The method according to claim 1, wherein the predetermined coordinate position is (x, y),
When the optical position information at the n-th light receiving unit corresponding to the predetermined coordinate position is u, the predetermined relational expression is: Where c _{1n to} c _5n are m (x ₁ ,
y ₁ ) to (x _m , y _m ), and optical position information at the n-th light receiving unit corresponding to the specific coordinate position is u _1n
Ｕ u _mn , the coefficient calculating means calculates the predetermined coefficients c _{1n to} c _5n as When the number of the light receiving means is N and the optical position information of the N light receiving means corresponding to the predetermined coordinate position (x, y) is u _{1 to} u _N , the calculating means , The predetermined coordinate position (x, y) is given by: The coordinate input device according to claim 1, wherein the coordinate is calculated according to 3. The coordinate input device according to claim 1, wherein a physical position of a light receiving surface corresponding to a light blocking position is used as optical position information in said light receiving means. 4. The coordinate input device according to claim 3, wherein a position calculated from a light intensity distribution on a light receiving surface corresponding to a light blocking position is used as the physical position. 5. The method according to claim 1, wherein when the light receiving means is constituted by a light receiving element array, a pixel number of the light receiving element array corresponding to a light blocking position is used as the optical position information. 2. The coordinate input device according to 2. 6. The plurality of light receiving units are at least two light receiving units, and the plurality of specific coordinate positions are the two light receiving units.
3. The coordinate input device according to claim 1, wherein a straight line connecting the optical center of one light receiving unit and the plurality of specific coordinate positions is at least five coordinate positions that do not coincide with each other. 7. A method for mounting a sensor head including a light emitting / receiving means according to claim 1 at a predetermined mounting position of a support means outside the input area according to claim 1, wherein the predetermined mounting position is: 7. A method according to claim 6, wherein straight lines connecting the optical center of the sensor head and the five coordinate positions according to claim 6 do not coincide with each other. 8. The method according to claim 7, wherein the sensor head is detachably attached to the attachment position of the support means. 9. A display device with a coordinate input device, comprising: a display device for displaying an image; and a coordinate input device having an input area provided on a display surface of the display device. Item 7. A display device with a coordinate input device, which is the coordinate input device according to any one of Items 1 to 6. 10. During a calibration operation before using a coordinate input device, a display surface of the display device may include:
The display device with a coordinate input device according to claim 9, wherein predetermined marks indicating the positions of the five points according to claim 6 or 7 are displayed or engraved. 11. During a calibration operation before using a coordinate input device, the display surface of the display device may include:
10. The display device with a coordinate input device according to claim 9, wherein a chart printed with predetermined marks indicating the positions of the five points according to claim 6 or 7 is attached. 12. A program for causing a computer to realize a function of calculating predetermined coordinates in a two-dimensional coordinate space by using a function of converting a two-dimensional coordinate space into a one-dimensional image space according to a predetermined conversion formula. Wherein the two-dimensional coordinate space is x, y, and the one-dimensional image space is u, the predetermined conversion formula is Where c _{1 to} c ₅ are predetermined coefficients that measure positions in the image space corresponding to a plurality of specific coordinates on the two-dimensional coordinate space, and calculate the plurality of specific coordinates and the positions on the image space. A function of executing a first mode of calculating a predetermined coefficient of the conversion equation based on the position of the conversion formula; measuring a position in the image space corresponding to predetermined coordinates in the two-dimensional coordinate space; A computer-readable recording recording a program for causing a computer to execute a second mode of calculating the predetermined coordinates by calculating a position in the image space corresponding to coordinates and the predetermined coefficient. Medium. 13. The recording medium according to claim 12, wherein the first mode is a function executed at the time of calibration, and the second mode is a function executed at the time of inputting coordinates.