JP4340302B2 - Coordinate input device - Google Patents

Description

  The present invention relates to a coordinate input device, and more particularly to a so-called touch panel type coordinate input device that inputs 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. This coordinate input device is used in combination with an electronic blackboard or a large display, or 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. Used for devices that digitize information.

  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 light emitting / receiving means 41, a coordinate input area 43, and a retroreflective member 44. The coordinate input area 43 has a quadrangular shape. For example, a display surface that electronically displays characters and images, a whiteboard that is written with a pen such as a marker, or the like is the coordinate input area.

  The optical coordinate input device 40 indicates the coordinate position of the pointing object 42 when the coordinate input area 43 is touched with a pointing object 42 such as a user's hand, finger, pen, support bar, etc. made of an optically opaque material. It is a device that detects and inputs the position information to a personal computer or the like.

Light emitting / receiving means 41 are provided at both upper ends of the coordinate input area 43. From the light emitting / receiving means 41 toward the coordinate input area 43, L ₁ , L ₂ , L ₃ ,. . . A bundle of L _m light beams (probe light) is irradiated. Actually, it is a fan-shaped light wave extending from the point light source 61 and traveling in parallel to the plane of the coordinate input area.

Further, a retroreflecting member 44 is provided in the peripheral portion of the coordinate input area 43 with the retroreflective surface facing the center of the coordinate input area 43. The retroreflective member 44 is a member having a characteristic of reflecting incident light in the same direction regardless of the incident angle. For example, when focusing on a certain beam 47 among 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 receives the same light path as the retroreflected light 46 again. It progresses so that it may return toward 41. The light receiving / emitting means 41 is provided with a light receiving means as will be described later, and detects whether or not the return light has returned to the light receiving / emitting means 41 for each of the probe lights L _{1 to} L _m. Can do.

  Consider a case where the user touches the position 42 with his / her 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. Accordingly, the retroreflected light of the probe light 45 does not reach the light receiving and emitting means 41, and the pointing object is placed on the extension line (straight line L) of the probe light 45 by detecting that the retroreflected light corresponding to the probe light 45 is not received. Can be detected.

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

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

  The light receiving / emitting means 41 includes a point light source 61, a condensing 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 retroreflecting member 55, and the retroreflected light 54 passes through the condenser lens 51 and reaches a position 57 on the light receiving element 50.

  Further, the beam traveling along the traveling direction 58 is reflected by the retroreflecting member 55, and the retroreflected light 59 reaches the position 56 on the light receiving element 50. Thus, the light emitted from the point light source 61, reflected by the retroreflecting member 55, and returned through 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. .

  Therefore, when the pointing object is inserted at a certain position and a certain beam is blocked, the light does not reach a point on the light receiving element 50 corresponding to the beam. From this, it is possible to know which beam is blocked by examining the light intensity distribution on the light receiving element 50.

  FIG. 20 is a diagram for explaining the operation when the pointing object is inserted and the beam is blocked. In FIG. 20, the light receiving element 50 is provided on the focal plane of the condenser lens 51. The light emitted from the point light source 61 toward the right side in FIG. 20 is reflected by the retroreflecting 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 condensing lens 51 is provided so as to coincide with the point light source position. Since the retroreflected light returning from the retroreflective member 55 passes through the center of the condensing lens 51, it travels in a symmetrical path to the rear of 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 substantially constant, but the light is blocked as shown in FIG. When the pointing object 60 is inserted, the beam passing therethrough is blocked, and a region (dark spot) having a low light intensity is generated at the position D _n on the light receiving element 50.

This position D _n is obstructed by not correspond to the emitted / incident angle theta _n of the beam can be calculated theta _n by detecting the D _n.
That is, θ _n is a function of D _n θ _n = arctan (D _n / f) Equation (1)
It can be expressed as. However, f is a distance between the condensing lens 51 and the light receiving element 50, and corresponds to the focal length of the condensing lens 51, as shown in FIG.

Here, in particular, θ _n is replaced with θ _nL and D _n is replaced with D _nL in the light emitting / receiving means 41 in the upper left of FIG. Further, in FIG. 21 for explaining the calculation method of the coordinate position, the conversion of the geometric relative positional relationship between the light emitting / receiving means 41 and the coordinate input area 43 makes it possible to change between the pointing object 60 and the x axis of the coordinate input area 43. The formed angle θ _L is a function of D _nL obtained by equation (1),
θ _L = g (θ _nL )
Where θ _nL = arctan (D _nL / f) Equation (2)
It can be expressed as.

Similarly, for the light emitting / receiving means 41 in the upper right of FIG. 18, the L symbol in the above formula is replaced with the R symbol, and the geometric relative positional relationship between the right light emitting / receiving means 41 and the coordinate input area 43 is changed. By conversion h
θ _R = h (θ _nR )
Where θ _nR = arctan (D _nR / f) Equation (3)
It can be expressed as.

As shown in FIG. 21, if the mounting interval of the light emitting / receiving means 41 in the coordinate input area 43 is w, the left corner of the coordinate input area 43 is the origin 70, and the x and y coordinates are as shown in FIG. The coordinates (x, y) of the point indicated by the pointing object 60 on the input area 43 are:
x = wtan θ _R / (tan θ _L + tan θ _R ) (4)
y = wtanθ _L · tan θ _R / (tan θ _L + tan θ _R )
Formula (5)
From equations (2), (3), (4), and (5), x and y can be expressed as functions of D _nL and D _nR .

That is, by detecting the positions D _nL and D _nR of the dark spots on the light receiving element 50 of the left and right light receiving / emitting means 41 and taking into account the geometrical arrangement of the light receiving / emitting means 41, Coordinates can be calculated. The coordinate calculation method described above is based on the principle of triangulation, and is described in Patent Document 1, for example.

JP-A-9-91094

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

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

Further, in the coordinate system having P and Q as the origin, the coordinates d that are obtained from equations (2) to (5) by the offset dx and dy due to the translation and the offset θ ₀ due to the rotation are known. x and y can be converted into a coordinate system having Q as the origin in the coordinate input area. Therefore, it is necessary to determine the mechanical position of the sensor head so that w, θ _offL , θ _offR , dx, dy, and θ ₀ are known.

  However, in general, assembling the sensor head so that all these parameters have predetermined values increases the cost in the device manufacturing process. In addition, there is a method in which these parameters are assembled so that they are within a small tolerance, and after the assembly, these parameters are measured and reflected in the calculation. However, this method is not practical due to the difficulty of measuring parameters after assembly.

  In addition, there is a problem that the above-mentioned parameters are deviated from the set values at the time of shipment due to vibration during transportation, and correct coordinate input operation cannot be performed at the time of delivery. Furthermore, even when the light emitting / receiving means is divided and transported for the convenience of transportation and packaging, the coordinate input surface (display surface, blackboard surface, etc.) Need to be reattached.

  However, it is difficult for a general user to perform the mounting again while maintaining accuracy, or a special jig or mechanism is required, which increases the cost. In addition to this, for example, in the case where an application where a user attaches to an arbitrary coordinate input surface and uses the sensor head portion formed by the light emitting / receiving means as a split portable type is the same in the conventional triangulation calculation method. 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,
An object of the present invention is to provide a coordinate input device that increases the degree of freedom of the attachment position of the light emitting and receiving means on the coordinate input surface.

  In the present invention, at the time of calibration, the relational expression describing the relationship between the light blocking position information and the reference point coordinates based on the light blocking position information and the reference point coordinates in the sensor head when the pointing object is inserted into the reference point. The coefficient of is calculated. The light blocking object is inserted by performing a predetermined calculation using information corresponding to the light blocking position generated in each sensor head and the previously calculated coefficient by the light blocking object inserted at the time of coordinate input. Output the coordinates.

  In the present invention, the 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.

  Furthermore, in the present invention, when calculating the coefficients during calibration, the coefficient matrix needs to be regular, so the number of reference coordinates is five, and the coordinates of these five points are the center of the light receiving means and each of the coordinates. They are arranged so that the straight lines connecting the coordinates of the points do not coincide with each other.

According to the present invention, even when a parameter related to the attachment position of the light emitting / receiving means on the coordinate input surface is unknown, or even if the parameter is changed for some reason even if it is known at the time of attachment, a simple process before using the apparatus is possible. Since the coordinates on the coordinate input surface can be correctly input by the calibration operation, the reliability is high and the convenience is improved.

Another object of the present invention is to calculate a coefficient of a relational expression that describes a relationship between a predetermined coordinate into which a light blocking unit is inserted at the time of calibration and position information of the blocked light corresponding thereto. As a condition that can be always calculated, the coefficient matrix of the simultaneous equations must be regular, so by limiting the number of coordinate points and how to place them as a reference, a coordinate input device that makes the coefficient matrix regular is necessary. It is to provide.

Another object of the present invention is to provide a coordinate input device that 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 the mode by himself / herself when the position of the light emitting / receiving means is shifted during use or immediately after transportation. The object is to provide a coordinate input device that can be calibrated.

Reference points (x ₁ , y ₁ ), (x ₂ , y ₂ ). . . The light blocking position information (u ₁₁ , u ₂₁ ,..., U ₅₁ ) and (u ₁₂ , u in the sensor head 1 and the sensor head 2 when the pointing object is inserted into (x ₅ , y ₅ ), respectively. ₂₂ ,..., U ₅₂ ) and the coordinates of the reference point are respectively stored in the first storage units 3 and 4 (step 103).

The reference point coordinates and the light blocking position information stored in the first storage units 3 and 4 are read into the coefficient calculation means 5 and 6. The coefficient calculating means 5 and 6 are provided with coefficients (c ₁₁ , c ₂₁ ,..., C ₅₁ ) and (c ₁₂ , c _{22 ,.} ) Is calculated (step 104) and stored in the second storage units 7 and 8 (step 105).

  The operation so far is the calibration operation mode, which is indicated by a thick arrow in FIG. These series of operations are performed before the user uses the coordinate input device or when installing the coordinate input device.

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

Light is blocked by 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, information u ₁ and u ₂ corresponding to the light blocking positions are acquired by the sensor heads 1 and 2 (step 106).

Further, the coefficients (c ₁₁ , c ₂₁ ,..., C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C ₅₂ ) stored in the second storage units 7 and 8 in the calibration operation mode described above. Is read (step 107), and the coordinate calculation unit 9 determines that u ₁ , u ₂ and (c ₁₁ , c ₂₁ ,..., C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C ₅₂ ). Is used to calculate coordinates according to equation (14) described later (step 108), and outputs the coordinates (x, y) into which a light blocking object such as a finger is inserted to a personal computer (not shown) (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 105) are performed in parallel. The coordinate calculation mode (steps 106 to 109) is executed. The calibration operation mode on the sensor head 1 side is executed, then the calibration operation mode on the sensor head 2 side is executed, and then the coordinate calculation mode is set. You may make it perform.

このときの写像ｆが推定できれば、これの逆写像を用いて、２次元のフィルム面上の像の位置から３次元の物体空間の物体の位置を推定することができる。 The coefficient calculation and coordinate calculation described above will be described in detail below.
In general, a camera system captures an object in a three-dimensional space and records the image on a two-dimensional film surface. FIG. 3 is a diagram for explaining the concept of the camera system. (X, y, z) is the object space coordinate, and p (x, y, z) is the position of the object. Further, (u, v) is an image space coordinate, which is a coordinate system representing the position of the image on the image plane. Point r is the principal point position of the lens. The point p on the three-dimensional object space is converted to a point q on the two-dimensional image space by the mapping f through the lens. Ie

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 using the inverse mapping.

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

  Here, a coordinate input system in the above-described optical coordinate input apparatus to which the present invention is applied will be considered. This coordinate system can be considered that 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 on a one-dimensional CCD and is constrained on a straight line along the array of CCD pixels.

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

c ₁ x + c ₂ y + c ₃ −c ₄ ux−c ₅ uy = u Formula (9)
Expression (9) relates the coordinates (x, y) on the coordinate input area where an object such as a finger is inserted and the light blocking position (information corresponding to the light blocking position) u on the light receiving element of the sensor head. It is an expression to attach. Here, c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ are coefficients and exist for each sensor head. In the calibration operation mode described above, this coefficient is determined for each sensor head.

Hereinafter, a method for 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).

未知係数が５個なので、式（１０）でｍ＝５とし、５個の既知の点ｐに対して、それぞれに対応する像面位置ｑを求める。図１における係数算出部５、６では、式（１０）を解いた式（１１）に従って、係数ベクトル｛ｃ_1n，ｃ_2n，．．．ｃ_5n｝をセンサヘッド毎に演算し、第２記憶部７、８に記憶する。

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 is obtained. In the coefficient calculation units 5 and 6 in FIG. 1, coefficient vectors {c _1n , c _{2n ,.} . . c _5n } is calculated for each sensor head and stored in the second storage units 7 and 8.

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

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

従って、座標入力領域上の物体座標（ｘ，ｙ）は、式（１２）を解いて、式（１３）で求められる。

Accordingly, the object coordinates (x, y) on the coordinate input area can be obtained by the equation (13) by solving the equation (12).

Since the number of sensor heads is 2 in the coordinate input device of the present invention, n = 2. The coordinate calculation unit 9 in FIG. 1 calculates the coordinates (x, y) on the coordinate input surface into which the pointing object such as a finger is inserted according to the equation (14) where n = 2 in the equation (13). Output.

(Example 2)
In the prior art, as described above, based on the position (D _nL , D _nR ) on the light receiving means of the light blocked by the light blocking means, the expected angle (θ _L ) of the light blocking means from the light receiving / emitting means. , Θ _R ), and a conversion table or conversion formula must be obtained in advance.

  On the other hand, the present invention uses 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. Has been greatly improved.

  The second embodiment is an embodiment in which a light blocking position (hereinafter referred to as a dip position) is detected. 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 method as in the first embodiment. FIG. 5 is a process 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 in FIG. 2 is replaced with the dip position information in FIG.

That is, the reference points (x ₁ , y ₁ ), (x ₂ , y ₂ ). . . (X ₅ , y ₅ ), 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. , 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 (step 203).

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

  Similar to the first embodiment, the operation so far is the calibration operation mode, and is an operation executed before the user uses the coordinate input device or when the coordinate input device is installed. Following the calibration operation mode, an operation mode for inputting coordinates is set.

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

Further, the coefficients (c ₁₁ , c ₂₁ ,..., C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C ₅₂ ) stored in the second storage units 7 and 8 in the calibration operation mode described above. Is read (step 207), and the coordinate calculation unit 9 determines that u ₁ , u ₂ and (c ₁₁ , c ₂₁ ,..., C ₅₁ ) and (c ₁₂ , c ₂₂ ,..., C ₅₂ ). Is used in the same manner as in the first embodiment (step 208), and coordinates (x, y) into which a light blocking object such as a finger is inserted are output (step 209).

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

FIG. 6 shows a pixel array of the light receiving elements. The light receiving element is a one-dimensional CCD 21, and FIG. 6 shows an example of a CCD having 2048 pixels. In FIG. 6, the pixels 22 on the CCD are indexed from 0 to 2047. For example, when the dip position indicated by A is at the pixel position with the index number 100 shown in FIG. 6, the dip position information or u in the equation (8) is the center of the CCD corresponding to D _n in FIG. It is not necessary to express the physical size on the CCD surface with the origin as the origin, and u can be calculated by substituting the index number of 100 as it is.

  However, if an index is used when determining the coefficient, the index is also used when measuring, and if the physical actual size on the CCD with the center of the CCD as the origin is used when determining the coefficient, the actual size is also used when measuring. Is used. Thus, it is necessary to use the same parameters when determining the coefficient and when measuring. It should be noted that a predetermined coefficient or offset may be applied to the above-described index, and parameters convenient for designing the apparatus can be arbitrarily used.

When the above-described pixel index is used, the pixel index can be obtained by the following method, for example. That is, the light intensity distribution on the CCD at a certain time is read into the array in correspondence with the CCD pixels. The same index as the pixel index is given to the array. For example, an array may be buf [0], buf [1],. . . buf [2047]
The light intensity at the CCD pixel assigned the index 100 is stored in buf [100], and the light intensity of the CCD pixel assigned the index 101 is stored in buf [101].

  In this way, the dip position is determined by software processing on the array storing the light intensities, for example, by a method described later, and the coordinates are calculated by substituting the index of the array of dip positions into u.

  As another method for obtaining the index of the CCD pixel, a method of counting the CCD transfer clock can also 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 in 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 the sake of simplicity, only one transfer clock is shown in this example, but there are actually elements that require two clocks whose phases are inverted at a period half that of the illustrated period. This is an example.

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

  The transfer clock 23 is input to the CCD 21 and input to the input terminal of the counter 26. Further, the counter 26 is reset by the scanning clock 24. Therefore, the output 27 of the counter 26 indicates what number of pixel charges have been output since the CCD 21 started scanning. The counter output 27 corresponds to the pixel index described above.

When detecting the dip position by hardware logic, it is more convenient to use the counter output as a pixel index because the circuit configuration is simplified. In the present invention, parameters that are convenient for designing circuits and software can be arbitrarily used by the designer, the degree of freedom in design is high, and it is particularly effective in reducing design man-hours and costs.
FIG. 9 is a diagram illustrating a dip position detection method 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 the waveform near the dip of the CCD sample hold output. The horizontal axis represents a CCD pixel or an array stored corresponding to the CCD pixel. As described above, ui is an index corresponding to the CCD pixel, such as an array index or a counter count value.

In the first detection method of the dip position, the CCD output value is sequentially scanned, and an index when a value smaller than a predetermined threshold appears is set to ui. Further, the scanning is continued and the index of the output value immediately before exceeding the threshold value again is set to ui + n. At this time, the dip position is calculated according to the equation (15).

In the second method of detecting the dip position, the CCD output value is sequentially scanned, and the index when a value smaller than a predetermined threshold appears is assigned as ui, ui + 1, ui + 2. . . Let ui + n. At this time, the dip position is calculated according to the equation (16).

(Example 3)
Example 3 is an example according to the arrangement method of the 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 housing 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 disposed on the support housing 33. A retroreflector 34 is also installed on the support housing 33. Note that a control unit including a coefficient calculation unit, a coordinate calculation unit, a storage unit, and the like is incorporated in, for example, a mechanism unit of the sensor head shown in FIG.

  The points p1, p2, p3, p4, and p5 in the coordinate input area 35 are the above-described calibration reference points whose coordinates are known. Point o is the center of one of the plurality of sensor heads. To be precise, it is the object side principal point of the light receiving lens.

  As described in the first embodiment, the coefficient matrix of the simultaneous equations must be regular as a condition under which the coefficient can always be calculated when calculating the coefficient using Expression (10). The coefficient matrix is made regular by setting the reference points for calibration to 5 points and limiting their arrangement.

  In order to satisfy the above-described conditions, the sensor head is disposed on the support housing 33 as follows. That is, the sensor head 2 and the reference point are arranged so that the line o connecting the points o and the line segments op-p1, op-p2, 0-p3, op-p4, op-p5 do not all match. Similarly, for the other sensor head 1, the reference point and the sensor head are arranged so that all the line segments connecting the light receiving lens principal point and the reference point do not coincide with each other.

  FIG. 11 is a diagram illustrating an example of a sensor head mounting mechanism. A protrusion (not shown) of the sensor head is inserted into the reference hole 36 and the long hole 37 of the support housing 33. Thereafter, as described above, the orientation of the sensor head is adjusted so that the line connecting the center of the sensor head and the points p1 to p5 does not coincide with each other, and the adjusted position is stopped with a screw or the like.

  FIG. 12 is a diagram illustrating another example of the sensor head mounting mechanism. The sensor head of FIG. 12 is detachable, and the sensor head is attached to the support housing 33 by attaching / detaching means 38 such as a suction cup. The sensor head mounting method in this example is the same as that described in FIG. In addition to the display described above, the coordinate input device of the present invention may be installed on a screen surface that projects a projector, for example.

(Example 4)
Example 4 is an example according to a method of displaying a reference point for calibration. FIG. 13 is a diagram illustrating a reference point display method 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 imprinted on the display surface 32.

  FIG. 14 is a diagram illustrating another example of the reference point display method. In FIG. 14, a reference chart 39 printed with reference points is pasted on the display surface 32. Since this reference chart 39 is not necessary when inputting coordinates, it is removed from the display surface 32.

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

(Example 5)
The fifth embodiment is an embodiment that switches between the calibration mode and the coordinate input mode. In other words, when the position of the sensor head (light emitting / receiving means) is shifted while using the coordinate input device or immediately after transportation, the user can arbitrarily switch the mode and calibrate by himself. This is an example.

  FIG. 15 shows the configuration of the fifth embodiment. The difference from the first embodiment is that switching means 12 to 17 for switching the operation state are provided. These switching means 12 to 17 are all operated in conjunction with an instruction from the operation state instruction means 18. When the switching means 12 to 17 are in the illustrated state, they are in the calibration operation mode. When the switching units 12 to 17 are switched, the coordinate input operation mode is set. As this operation state instruction means 18, for example, a method such as an instruction from the user to the switching means is adopted.

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

  Start represents the starting point of processing. 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 by at least one calibration operation mode.

  After the processing is started at the start, it is determined whether the operation state 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 means 12-17. Alternatively, a method of making a determination by referring to a flag corresponding to the state of the switching means 12 to 17 can be adopted.

  If it is determined that the calibration operation mode is selected, the operation of start 1 is entered and the calibration operation is performed (steps 302 to 306). Otherwise, the operation of start 2 is entered and the normal coordinate input operation is performed (step). 307-310). When one operation of each operation is completed, the operation returns to the start again to determine whether or not the calibration mode is selected, and the same operation is performed.

(Example 6)
The sixth embodiment is an embodiment for realizing the present invention by software, and FIG. 17 shows an example of the system configuration. In the system configuration, the coordinate input unit 80 includes, for example, a 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, calculates the coordinates by executing the processing steps and processing functions of the above-described embodiments 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-described processing is recorded on a recording medium such as the CD-ROM 85, and is executed by reading the program recorded on the medium from the CD-ROM device 84 and installing it in the system. The described processing function is realized. In addition to the medium, the above-described program is provided by downloading from a server or the like via the communication device 86 and the network 87.

  As described above, the case where the present invention is applied to the recursive light projection method has been described. However, the present invention is not limited to this, and the coordinate input surface is scanned by a sensor head (FIG. 23) employing an image pickup method or a polygon mirror. When the beam reflected by the reflection sheet is detected by a photodetector (PD) and the beam is blocked on the coordinate input surface by a blocking object such as a finger, the beam corresponding to that point is not detected by the PD but is detected. The present invention can also be applied to an optical scanning method (see, for example, Japanese Patent Application Laid-Open No. 11-110116) that calculates a position corresponding to a beam that has not occurred by triangulation.

It is a figure which shows the structure of Example 1 of this invention. It is a processing flowchart concerning Example 1 of the present invention. It is a figure explaining the concept of a camera system. It is a figure which shows the structure of Example 2 of this invention. It is a processing flowchart concerning Example 2 of the present invention. It is a figure which shows the pixel arrangement | sequence of a light receiving element. 4 is a time chart showing a CCD transfer clock, a scanning clock, and a sample hold output of a photodiode arranged in a CCD pixel, that is, a CCD video output. It is a figure which shows the structure which acquires a CCD pixel index using a counter. It is a figure explaining the detection method of the dip position in a dip position information detection part. The structure which has arrange | positioned the coordinate input device of this invention on the display is shown, (a) is the top view, (b) is the side view. It is a figure which shows an example of the attachment mechanism of a sensor head. It is a figure which shows the other example of the attachment mechanism of a sensor head. It is a figure explaining the display method of the reference point at the time of installing the coordinate input device of this invention on an electronic display, for example. It is a figure explaining the other example of the display method of a reference point. It is a figure which shows the structure of Example 5 of this invention. It is a processing flowchart concerning Example 5 of the present invention. It is a figure which shows the structure of Example 6 of this invention. It is a figure which shows the structure of the optical coordinate input device with which this invention is applied. It is a figure which shows the internal structure of the light emitting / receiving means of FIG. It is a figure explaining operation | movement when a pointing object is inserted and a beam is interrupted | blocked. It is a figure explaining the method of calculating a coordinate position based on the principle of triangulation. It is a figure which shows the example which has arrange | positioned the sensor head in the vicinity of the coordinate input area. It is a figure which shows the sensor head which takes an imaging system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Sensor head 3, 4 1st memory | storage part 5, 6 Coefficient calculation part 7, 8 2nd memory | storage part 9 Coordinate calculation part 10, 11 Dip position information detection part 12-17 Switching means 18 Operation | movement state instruction | indication 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 Elongated hole 38 Detaching 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 Retroreflected 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 Part 81 CPU
82 Memory 83 Display device 84 CD-ROM device 85 CD-ROM
86 Communication device 87 Network

Claims (5)

A plurality of light emitting means; a reflecting means for reflecting the light emitted from the light emitting means toward the light emitting means; and a plurality of light receiving means for receiving the light reflected by the reflecting means. In the input area formed by the optical path of the reflected light, when the optical path is blocked by inserting a predetermined light blocking means into the input area, the coordinate position where the light blocking means is inserted is calculated. A coordinate input device for inputting, wherein a relationship between a predetermined coordinate position where the light blocking unit is inserted and optical position information in the plurality of light receiving units corresponding to the predetermined coordinate position is a predetermined relational expression. The relational expression is satisfied based on a plurality of specific coordinate positions where the light blocking means are inserted and optical position information on the plurality of light receiving means corresponding to the specific coordinate positions. Coefficient calculation means for calculating a predetermined coefficient, and a predetermined calculation using the predetermined coordinate position using optical position information and the predetermined coefficient in the plurality of light receiving means corresponding to the predetermined coordinate position. And calculating means for calculating by
When the predetermined coordinate position is (x, y) and the optical position information in the _nth light receiving means corresponding to the predetermined coordinate position is un ,
The predetermined relational expression is

And
Here, c _{1n to} c _5n are m (x ₁ , y ₁ ) to (x _m , y _m ), where the plurality of specific coordinate positions, which are predetermined coefficients in the n-th light receiving means, are used for the identification. When the optical position information in the n-th light receiving means corresponding to the coordinate position of u _{1n to} u _mn is
The coefficient calculation means calculates the predetermined coefficients c _{1n to} c _5n ,

According to
When the number of the light receiving means is N and the optical position information in the N light receiving means corresponding to the predetermined coordinate position (x, y) is u _{1 to} u _N ,
The arithmetic means calculates the predetermined coordinate position (x, y),

A coordinate input device that calculates according to the above. 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 the light receiving means. The coordinate input device according to claim 2, wherein a position calculated from a light intensity distribution on the light receiving surface corresponding to the light blocking position is used as the physical position. 2. The coordinate input device according to claim 1, wherein when the light receiving means is composed of a light receiving element array, a pixel number of a light receiving element array corresponding to a light blocking position is used as the optical position information. The plurality of light receiving means are at least two light receiving means, and the plurality of specific coordinate positions include at least five points where straight lines connecting the optical centers of the two light receiving means and the plurality of specific coordinate positions do not coincide with each other. The coordinate input device according to claim 1, wherein the coordinate input device is a coordinate position of

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