JP2017058883A - Coordinate input device, and control method, control device, and computer program therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate input technique capable of acquiring input coordinates of each indication tool even when reflected light from a plurality of indication units partially overlaps with each other.SOLUTION: A coordinate input device detects an indication position on an input plane, including: first and second sensor unit, each of which comprises a light projecting unit for projecting light onto the input plane and a light receiving unit having a plurality of light receiving pixels for receiving reflected light, the reflected light being caused by indication means indicated on the input plane reflecting the projected light; and acquisition means for detecting a direction of indication made by indication means on the basis of a received light distribution of reflected light on the light receiving unit in each sensor unit and for acquiring an indication position on the basis of the direction. When received light distributions of reflected light from a plurality of indication means overlap with each other on one of the light receiving units, the acquisition means identifies light receiving pixels corresponding respectively to first and second light quantity levels, and determines true or false of a plurality of candidate coordinate points on the basis of a positional relationship between the light receiving pixel corresponding to the first light quantity level and the light receiving pixel corresponding to the second light quantity level.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a coordinate input device, a control method thereof, a control device, and a computer program, and more particularly to a technique for optically detecting a coordinate position input to a coordinate input surface by an instruction unit.

  Various types of coordinate input devices (touch panel and digitizer) that detect a coordinate position input to a coordinate input surface by an instruction unit such as a finger or a stylus to input or select information have been proposed or commercialized. For example, a touch panel that can easily operate a PC (personal computer), a tablet terminal, a smartphone, or the like by touching the screen with a finger without using a special instrument or the like is widely used.

  There are various coordinate input methods such as a resistive film method, an electromagnetic induction method, an electrostatic induction method, and an optical method. Japanese Patent Application Laid-Open No. 2004-260688 describes a configuration that employs a direct reflected light method that obtains an indicated position by reflected light of an instruction unit on an input surface among optical methods. In the configuration of Patent Document 1, when light projected from a plurality of light projecting units is reflected by an instruction unit on the input surface, the reflected light is detected by a plurality of light receiving units, and each light receiving unit detects incident light. The indicated position is specified based on the angle.

  The nature of the reflected light from the indicating unit depends on the reflecting surface state of the indicating unit. When the reflecting surface such as a finger or a pen does not have retroreflective properties as the instruction unit, the reflected light from the instruction unit becomes diffused light. Diffused light diffuses over a wide range as its optical path length increases. Accordingly, the intensity of light received by the light receiving unit varies greatly depending on the distance from the instruction unit to the light receiving unit. Therefore, there is known an optical coordinate input device including a method using not only reflected light from an instruction unit but also light shielding information.

  In a configuration in which coordinates are input using reflected light or light shielding information, when a plurality of instructions are input simultaneously by a plurality of instruction units, depending on the positional relationship between the input position of the instruction unit and the light receiving unit, the input of the instruction unit The position may not be correctly identified. Therefore, in order to deal with a plurality of inputs, it is necessary to perform a true / false determination that determines the actually indicated position from a larger number of candidate points than the number of actually input instruction units.

  Patent Documents 2 and 3 describe a configuration in which the true / false determination is performed by comparing the widths in the pixel direction of the light reception information detected by the light receiving unit.

JP-A-8-249112 JP 2001-318759 A JP 2003-186616 A

  However, as in the configurations of Patent Document 2 and Patent Document 3, in the configuration in which the width of the light reception information detected by the light receiving unit is compared in the pixel direction and the true / false determination at the time of multiple inputs is performed, the coordinates of the indicated position are previously set. Need to ask. Further, it is difficult to accurately obtain the indicated position when a part of the received light information is duplicated.

  In the present invention, when coordinates are input using a plurality of pointing tools, the input coordinates of each pointing tool can be accurately obtained even when the reflected light from the plurality of pointing parts partially overlaps. An object is to provide a technique of coordinate input that is possible.

In order to achieve the above object, a coordinate input device according to the present invention comprises the following arrangement. That is,
A coordinate input device for detecting a designated position with respect to an input surface,
A light projecting unit that projects light onto the input surface, and a light receiving unit that includes a plurality of light receiving pixels that receive reflected light reflected by the projecting unit instructed on the input surface. First and second sensor units;
An acquisition unit that detects a direction of an instruction by the instruction unit based on a received light distribution of the reflected light in the light receiving unit for each of the first and second sensor units, and acquires an instruction position by the instruction unit based on the direction. And
The acquisition unit specifies a light receiving pixel corresponding to the first and second light amount levels when a light reception distribution due to reflected light from a plurality of instruction units overlaps in any one of the light receiving units. Based on the positional relationship between the light receiving pixels corresponding to the light quantity level and the light receiving pixels corresponding to the second light quantity level, the truth of the plurality of coordinate candidate points is determined.

  According to the present invention, when coordinates are input using a plurality of pointing tools, the input coordinates of each pointing tool are accurately acquired even when the reflected light from the plurality of pointing parts partially overlaps. It is possible to provide a technique of coordinate input that is possible.

The figure which shows schematic structure of a coordinate input device The figure which shows schematic structure of a coordinate input device The block diagram which shows schematic structure of the electric circuit contained in a coordinate input device The figure which shows the light reception distribution in the light receiving section Diagram showing the relationship between the distance from the sensor unit to the indicator and the received light level Timing chart for sensor unit operation Explanatory drawing which acquires a center pixel from light reception distribution in a light-receiving part The figure which shows schematic structure of a coordinate input device The figure which shows the light reception distribution in the light receiving section Flow chart showing the processing procedure of truth determination Figure showing the light distribution in the light receiving part Flow chart showing the processing procedure of truth determination

  Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings. The configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

<< Embodiment 1 >>
(Configuration of coordinate input device)
First, a schematic configuration of a coordinate input device according to an embodiment (Embodiment 1) of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a planar coordinate input surface such as a whiteboard. The coordinate input surface 1 is instructed by touching the coordinate input surface 1 with an instruction unit 2 such as a finger or a pen, and performs coordinate input. In FIG. 1, the case where it instruct | indicated with the some instruction | indication part (here 2 instruction | indication parts 2-1 and 2-2) is illustrated. The optical action and operation will be described later.

  Of course, the coordinate input surface 1 is not limited to the plane of the whiteboard, and may be a plane that is not normally assumed as an input surface, such as a wall surface. The coordinate input surface 1 is also used as a projection screen of a front projector, for example. The coordinate input device 3 of the present embodiment is mounted on the periphery of the coordinate input surface 1 as shown in FIG. From the coordinate input device 3, coordinate information on the coordinate input surface 1 at the position designated by the instruction unit 2 is transmitted to a PC or the like (not shown), and the coordinates of the designated position are coordinated via a front projector that is also connected to the PC. Projected and displayed on the input surface 1. Therefore, the coordinate input surface 1 can be operated as if it were drawn on paper or as a touch panel.

  The coordinate input device 3 includes two sensor units 4-1 and 4-2 arranged at a predetermined distance d, an arithmetic control circuit 5 connected to the sensor units 4-1 and 4-2, and an unillustrated An interface unit with an external PC is provided. As described above, the coordinate input device 3 is attached to the periphery of the input area of the coordinate input surface 1, for example, the corner area. As a mounting part in that case, when the coordinate input surface 1 is comprised with an iron plate, a magnet part is provided in the housing back surface not shown of the coordinate input device 3 of this embodiment. Each of the sensor units 4-1 and 4-2 includes a light projecting unit and a light receiving unit, and details will be described with reference to FIG.

  FIG. 2 is a schematic cross-sectional explanatory view in which the coordinate input device 3 of the present embodiment is mounted on the coordinate input surface 1 and the state designated by the instruction unit 2 is viewed from the side. In the sensor unit 4, a light projecting unit and a light receiving unit are provided. The light projecting unit includes a drive unit 6 having an electric circuit for driving the light source and a light source 7 such as an infrared LED or an infrared laser. The light receiving unit includes a light receiving optical system 8 such as a light receiving lens, an image pickup device 9 such as a CCD or a CMOS, and a sensor substrate 10 on which the image pickup device 9 is mounted. The imaging device 9 is composed of a plurality of pixels arranged in a one-dimensional line, and the direction of the instruction unit 2 viewed from the sensor unit 4 is determined based on the distribution of the amount of light detected by each pixel. In the example of FIG. 2, the light projecting unit and the light receiving unit are arranged at substantially the same position so as to overlap vertically in the vertical direction with respect to the two-dimensional coordinate system formed on the coordinate input surface 1. From the light emission source 7, a light beam spreading in a fan shape is projected in a two-dimensional direction parallel to the coordinate input surface 1. The fan-shaped projection range is set so as to cover the input area of the assumed coordinate input surface 1 for both the sensor units 4-1 and 4-2. In the present embodiment, an example in which the formation of the fan-shaped projection range is realized by providing the light emission source 7 with projection directivity is described. A system may be provided and realized. Or in order to form a fan-shaped projection range, it is good also as a structure which scans a predetermined angle range in parallel with the coordinate input plane 1 by using the light emission source 7 as a laser. Each of the sensor units 4-1 and 4-2 has the above-described configuration.

  As shown in FIG. 1 and FIG. 2, when the input area of the coordinate input surface 1 is instructed by the instruction unit 2, the light from the light emitting source 7 is reflected by the surface of the instruction unit 2 and a part of the reflected light is received light. Light is received by the imaging device 9 via the system 8. Further, it is converted into an electric signal by the imaging device 9, and the electric signal is transmitted to the arithmetic control circuit 5 through the sensor substrate 10. This electric signal is information corresponding to the voltage of the electric signal corresponding to the pixel number in the imaging device 9 of the sensor unit 4, that is, the light amount level, and is so-called light amount distribution information. If data related to the correspondence between the angle information in the direction parallel to the coordinate input surface 1 for the sensor unit 4 and the pixel number of the imaging device 9 is acquired in advance, the reflected light from the instruction unit 2 is obtained from the pixel light quantity distribution information. Angle information can be obtained. Since the sensor units 4-1 and 4-2 are arranged at a known predetermined distance d, the arithmetic control circuit 5 determines each of the sensor units 4-1 and 4-2 from the light quantity information of the reflected light. Based on the angle information, the coordinates of the instruction unit 2 are calculated by a known triangulation technique. For example, the position of the light source, the number of sensor units, and the like are not limited to the above as long as equivalent actions and effects can be obtained.

  FIG. 3 is a block diagram showing a schematic configuration of an electric circuit included in the coordinate input device 3 of the present embodiment. The arithmetic control circuit 5 as the control device in the present embodiment is further provided with a coordinate arithmetic circuit unit 11 as an operation function block. The coordinate calculation circuit unit 11 calculates angle information from pixel information in which reflected light is detected in each of the sensor units 4-1 and 4-2, and calculates instruction coordinates of the instruction unit 2. Further, a light projecting drive circuit unit 12 for controlling the drive unit 6 of the light projecting unit and an interface circuit unit 13 for transmitting the calculated coordinate information to a PC (not shown) are installed.

  The light projection intensity is controlled by controlling the drive current or drive pulse width of the light emission source 7 to emit light from the light projection drive circuit unit 12 to the drive unit 6. In the following, an example in which the drive current is controlled with a constant drive pulse will be described, but the drive pulse may be controlled or both may be controlled. The coordinate calculation circuit unit 11 that has received the light reception signal of the reflected light from the instruction unit 2 from the sensor substrate 10 derives the angle information from the pixel information related to the reflected light and calculates the instruction coordinates of the instruction unit 2 as described above. To do. The division of the circuit block is shown for convenience in terms of the operation function, and does not necessarily indicate the division of the actual hardware configuration of the electric circuit. For example, in the hardware in which the main arithmetic circuit is configured by an FPGA and a DSP, the functions are not assigned individually, but have both the functions of the coordinate arithmetic circuit unit 11 and the light projecting drive circuit unit 12, respectively. But you can. Note that FPGA is an abbreviation for Field-Programmable Gate Array, and DSP is an abbreviation for Digital Signal Processor.

(Coordinate input and light distribution)
Next, a relationship between the indication position of the indication unit 2 and the light reception distribution in the imaging device 9 of each sensor unit 4 will be described. FIG. 4 is a diagram illustrating a received light amount distribution in the light receiving unit of the reflected light reflected by the instruction unit 2 from the light emitted from the light projecting unit of the sensor unit 4. 4A and 4B show the received light amount distributions in the sensor units 4-1 and 4-2, respectively. The horizontal axis corresponds to the pixel number of the imaging device 9, and the vertical axis corresponds to the received light level. Shows the voltage.

  Reference numerals 2-1 and 2-2 in FIG. 4 denote corresponding instruction units in FIG. Here, as shown in FIG. 1, the received light amount distribution when the positions are indicated at positions a and b by the two instruction units 2-1 and 2-2 is shown for each sensor unit 4-1 and 4-2. This is shown in FIGS. 4 (a) and 4 (b). As shown in FIG. 4A and FIG. 4B of the received light amount distribution, depending on the positional relationship between the two instruction units 2-1 and 2-2 and the sensor units 4-1 and 4-2 shown in FIG. In addition, the received light amount distributions in the sensor units 4-1 and 4-2 are in different states.

  First, when viewed from the sensor unit 4-2, the positions a and b of the instruction units 2-1 and 2-2 in FIG. 1 are different in distance, but have a relationship in which the detection angle is sufficiently separated. Therefore, the light reflected from the light projecting unit of the sensor unit 4-2 is reflected by the instruction units 2-1 and 2-2 on the pixel number axis of the imaging device 9, as shown in FIG. The light distribution is separated separately. On the other hand, when viewed from the sensor unit 4-1, the positional relationship between the positions a and b of the instruction units 2-1 and 2-2 in FIG. 1 is different in distance and close in angle, resulting in overlapping light reception distributions. In that case, all the light from the light projecting unit of the sensor unit 4-1 is reflected and received by the instruction unit 2-1 positioned at a closer to the sensor unit 4-1. However, part of the light from the light projecting unit of the sensor unit 4-1 is partially directed to the instruction unit 2-2 located at b far from the sensor unit 4-1. The light is blocked by 1 and does not reach, and only the remaining light that has not been blocked reaches, reflects, and is received. Therefore, the reflected light reflected by the instruction units 2-1 and 2-2 has a light reception distribution that overlaps on the pixel number axis of the imaging device 9 as shown in FIG. The broken line portion shown in FIG. 4A is a light amount distribution that would have been obtained if the instruction unit 2-1 did not exist, but this information cannot be obtained.

  FIG. 5 is an explanatory diagram showing the relationship between the distance from the sensor unit 4 to the instruction unit 2 and the received light signal level (voltage). As described in the background art, the reflected light from the pointing unit is diffused light and dissipates over a wide range as the optical path length increases. Therefore, as the distance from the instruction unit 2 to the light receiving unit increases, the light receiving intensity in the light receiving unit is significantly reduced. FIG. 5 shows the relationship. Therefore, in the received light amount distribution of FIG. 4, the light amount level reflects the distance from the sensor units 4-1 and 4-2 to the instruction units 2-1 and 2-2. That is, also in the light quantity distribution of FIG. 4A in which the reflected light reflected by the instruction units 2-1 and 2-2 overlaps, from the sensor unit 4-1 to the instruction units 2-1 and 2-2. As described above, the magnitude relationship between the distances is directly shown in the light amount level. The instruction position detection using the level difference due to this distance will be described later.

(Operation timing of sensor unit)
FIG. 6 is a timing chart showing the control signal output from the arithmetic control circuit 5 to operate the sensor unit 4 and the operation of the sensor unit 4. Reference numerals 71, 72, and 73 are control signals for image pickup device control by the coordinate calculation circuit unit 11 of the calculation control circuit 5. Reference numeral 71 denotes a shutter signal (SH signal), and the shutter release time of the imaging device 9 is determined by the interval of the SH signal. Reference numeral 72 denotes a gate signal to the imaging device 9 of the sensor unit 4-1, and in response to a trigger of the gate signal 72, transfer of the charge of the photoelectric conversion unit inside the imaging device 9 to the reading unit is started. 74 is a signal indicating the shutter release time of the imaging device 9 of the sensor unit 4-1. 73 is a gate signal to the imaging device 9 of the sensor unit 4-2, and 75 is a signal indicating the shutter release time of the imaging device 9 of the sensor unit 4-2.

  Reference numerals 76 and 77 denote drive signals to the light emission sources 7 of the sensor unit 4-1 and the sensor unit 4-2 by the light projection drive circuit unit 12 of the arithmetic control circuit 5, in particular. In order to turn on the light emission source 7 of the sensor unit 4-1 in the first cycle of the SH signal 71, a drive signal 76 is supplied to the light emission source 7 through each drive unit 6. Then, a signal 77 is generated and supplied to turn on the light emission source 7 of the sensor unit 4-2 at the next cycle of the SH signal 71. After the driving of the light source 7 and the shutter release of the imaging device 9 are completed, the light reception signal of the imaging device 9 is read out to the coordinate calculation circuit unit 11. Also, angle information is calculated from the pixel information by the following method.

(Coordinate judgment based on received light distribution)
FIG. 7 is an explanatory diagram of a process of calculating pixel information corresponding to the indicated position, that is, angle information, from the light amount distribution information related to the reflected light from the indication unit 2 of the sensor unit 4 in the coordinate calculation circuit unit 11. In FIG. 7, the horizontal axis represents the pixel number of the imaging device 9, and the vertical axis represents the voltage of the received light signal.

  First, two pixels adjacent to each other before and after the rise and fall of the light amount distribution signal when the obtained light reception signal is sliced at a predetermined detection threshold voltage V1 are obtained, and V1 is obtained by proportional calculation (linear interpolation). Each pixel Ns, Nt corresponding to is calculated. Further, the intermediate pixel Npv of the two pixels calculated for the rising and falling is derived as a pixel corresponding to the angle of the instruction unit 2.

In the example of FIG. 7, before and after the light amount distribution signal crosses the detection threshold voltage V1 at the fall, the pixels are N _f−1 and N _f , and the voltages of these pixels are L _t−1 and L _t , respectively. It is. Here, when the light quantity distribution signal between the pixels of the pixel numbers N _f−1 and N _f is approximated by a straight line, the pixel number Nt of the pixel corresponding to V1 is as follows.

_{Nt = N f-1 + (} N f -N f-1) · (L t-1 -V 1) / (L t-1 -L t)
Similarly, the pixel number Ns of the pixel that crosses the detection threshold voltage V1 when the light amount distribution signal rises can be obtained. Then, the intermediate pixel Npv is calculated as an average value of Ns and Nt (Npv = (Ns + Nt) / 2).

  Based on the pixel information of the intermediate pixel, the angle of the designated position is obtained using a function indicating the relationship between the pixel and the angle acquired and set in advance. Then, the coordinates of the indication position of the indication unit 2 are calculated from the predetermined distance d between the sensor units and the angle corresponding to the indication unit 2 in each sensor unit. In this way, the coordinates can be calculated based on the center value of the pixel width at one detection threshold.

  An example in which coordinates are calculated by applying this method when an instruction is given by a plurality of instruction units 2 will be described with reference to FIGS. FIG. 8 is a diagram illustrating the coordinate input surface 1 on which coordinates are input by the two instruction units 2-1 and 2-2, and FIG. 9 illustrates the light reception distribution in the sensor units 4-1 and 4-2. FIG.

  Unlike the case of FIG. 4, the positional relationship between the sensor units 4-1 and 4-2 and the instruction units 2-1 and 2-2 in the case of FIG. 8 is viewed from either of the sensor units 4-1 and 4-2. However, the instruction units 2-1 and 2-2 are separated from each other. Therefore, as shown in FIGS. 9A and 9B, the received light amount distribution is the light amount distribution of the reflected light from the instruction units 2-1 and 2-2 in both the sensor units 4-1 and 4-2. Are separated. With respect to this separated light amount distribution, it is possible to obtain an intermediate pixel of two pixels calculated for rising and falling by slicing with the detection threshold voltage V1, and to obtain an angle by the above-described processing.

  Since two angles corresponding to the instruction units 2-1 and 2-2 are calculated for both the sensor units 4-1 and 4-2, as a result, as shown in FIG. 8, a, b, a Four coordinate candidate points ', b' are obtained. Then, it is necessary to further determine which of a, b, a ′, and b ′ is the actually designated position. This is so-called true / false determination, and can be performed by, for example, a method of comparing the widths of the light reception information of the four coordinate candidate points in the pixel direction, a method of comparing the light amount levels of the light reception information, or the like. However, as shown in FIG. 4 (a), when there is a partial overlap in the light reception information in any of the sensor units 4, each of the light reception information is simply compared with the width in the pixel direction and the light intensity level. It is difficult to obtain the position of the center pixel by separating received light information. Therefore, in such a case, it is generally difficult to determine the true or false unless an additional configuration such as a further sensor unit or a device that implements the inheritance algorithm is provided. In addition, when the central pixel of the plurality of reflected light distributions exactly matches, the plurality of pointing tools are present in the direction of the angle corresponding to the central pixel, and therefore the coordinates of each pointing tool are accurately obtained. Can do.

(Falseness judgment process)
In the configuration of the present embodiment, when a part of the plurality of light amount distributions overlaps in the light receiving unit, the respective light amount distributions are separated from the shape of the overlapped light amount distribution, and the true / false determination is performed. Specifically, the light receiving pixels corresponding to the first and second light quantity levels are specified, and based on the positional relationship between the light receiving pixels corresponding to the first light quantity level and the light receiving pixels corresponding to the second light quantity level. The truth of a plurality of coordinate candidate points is determined. For this reason, even when there is a partial overlap in the light reception information of the reflected light from the instruction unit 2 in the sensor unit 4, it is possible to determine whether it is true or false. This will be described with reference to the flowchart of FIG. The following steps are executed based on the control of the arithmetic control circuit 5 as a control device.

  First, in S <b> 101, the light emitting source 7 is driven to emit light, and the imaging device 9 receives reflected light from the instruction unit 2. Then, the received light data is read and acquired.

  Next, in S102, as shown in FIG. 4, two pixels before and after the rise and fall of the light amount distribution signal when the received light signal is sliced with a relatively low predetermined detection threshold V1 are obtained. The detection threshold V1 is set to a value slightly smaller than the light reception level of the reflected light from the instruction unit 2 when an instruction is given from the instruction unit 2 at a position in the coordinate input surface 1 farthest from the light receiving unit, for example. Can do. Further, each pixel corresponding to V1 is calculated by proportional calculation. This is the first stage of the light quantity distribution information processing described with reference to FIG. Then, rising and falling are counted as one set of reflected light, and information on whether the number of reflected light signals received by each sensor unit 4 is two or one is obtained.

  Next, in S103, the combination of the number of reflected light signals received by each sensor unit 4 (the number of received light of the instruction unit 2-1 and the number of received light of the instruction unit 2-2) is (2, 1) or ( 1, 2). This determination target is whether or not the positional relationship between the sensor unit 4 and the instruction unit 2 is as shown in FIG. That is, as shown in FIG. 4, the number of light reception information of one of the sensor units 4 is 2, but the light reception information of the other sensor unit 4 is duplicated and cannot be separated, and the number of light reception information is 1. Whether this is the case. As described above, the number of received light information is 1 when at least a part of the received light distribution from the instruction units 2-1 and 2-2 as viewed from the sensor unit 4 is overlapped, and 2 when not overlapped. Become. When the combination of the number of received signals (the number of received light of the instruction unit 2-1 and the number of received light of the instruction unit 2-2) is determined to be (2, 1) or (1, 2) (YES in S103) ), The process proceeds to S104. If it is determined that (1, 1) or (2, 2) (NO in S103), the process proceeds to S107.

  In S104, the following processing is performed on the received light information in which the number of detected signals is 1. When the received light signal is sliced again with the detection threshold V2 having a level relatively higher than the detection threshold V1, two pixels before and after the rise and fall of the light amount distribution signal are obtained, and the rise and rise corresponding to V2 are obtained by proportional calculation. Each falling pixel is calculated. As shown in FIG. 1, the difference in the light reception level is caused by the difference in the distance to the two instruction units 2 with respect to one sensor unit 4. The detection threshold V2 is set to a value corresponding to the difference between the detected light reception levels. For example, as shown in FIG. 4A, the detection threshold V2 is set to a level higher than the reflected light level from the instruction unit 2-2 at the position b of the assumed distance difference with respect to the instruction unit 2-1. The Such a detection threshold value V2 can be a value between the received light amounts corresponding to the peaks of the two received light distributions detected by the light receiving unit having the detected number of signals of 2, for example. Therefore, in S104, the rising and falling pixel information of the light amount distribution signal sliced only with respect to the light reception signal of the reflected light from the instruction unit 2-1 at the position a is obtained with the detection threshold V2.

Next, in S105, the corresponding angle is calculated by a function of the pixel and the angle acquired in advance from the rising and falling pixel information of the light amount distribution signal corresponding to the two thresholds of the detection threshold V1 and the detection threshold V2. The detection threshold V1 is processed not only for the light reception information whose detected signal number is 1 but also for the light reception information of the other sensor unit 4-2 whose detected signal number is 2. For the other sensor unit 4-2 in which the number of received light information is 2, four rise and fall angle meters for each of the instruction units 2-1 and 2-2 sliced with the detection threshold V1 are calculated. . On the other hand, for the sensor unit 4-1 having the number of light reception information of 1, two pieces of angle information of rising and falling sliced by the detection threshold V 1 are calculated. The angle information of the sensor unit 4-1 in which the number of received light information is 1 indicates the range of both ends of the angle where the reflected light of the instruction units 2-1 and 2-2 shown in FIG. . Four coordinate candidate points a, b, a ′, and b ′ shown in FIG. 1 are calculated based on the combination of the sensor unit 4-2 and the angle information of the sensor unit 4-1. Based on the end angle of the received light information, the indicated position candidate can be calculated using inscribed circles of three intersecting lines. That is, for each of the two light reception information detected in the sensor unit 4-2,
-Two straight lines corresponding to the angle of both ends.
One straight line corresponding to the angle of one end of the received light information detected by the sensor unit 4-1.
Four circles inscribed in the three straight lines correspond to coordinate candidate points a, b, a ′, and b ′. In S106, it is next determined whether a, b, a ′, or b ′ is the actually designated position.

  Next, in S106, the intermediate pixel of the rising and falling pixel information of the light quantity distribution signal corresponding to the two threshold values of the detection threshold value V1 and the detection threshold value V2 is calculated. Then, the central pixel is compared, and the true / false determination is performed based on the comparison result. As shown in FIG. 4A, the rising and falling pixel information sliced by the detection threshold V1 is reflected by the reflected light of the indicating unit 2-1 at the position a and the reflected light of the indicating unit 2-2 at the position b. This is due to the overlapped light reception information. Here, the pixel width formed by the rise and the fall by the detection threshold V1 is W1, and the center pixel is C1. On the other hand, the rising and falling pixel information sliced by the detection threshold V2 is based on the light reception information of the reflected light of only the reflected light of the instruction unit 2-1 at the position a, as shown in FIG. . The reflected light from the instruction unit 2-1 at the position a is closer to the sensor unit 4-1, than the instruction unit 2-2 at the position b. Therefore, the light reception level is large and the detection threshold V2 is relatively large. Is detected. Here, the pixel width formed by the rise and the fall by the detection threshold V2 is W2, and the center pixel is C2.

  Here, the pixel numbers of the central pixels C1 and C2 are compared. In the case of the positional relationship of FIG. 1, as shown in FIG. 4A, C2 <C1, and with this information, the indicating unit 2-1 is positioned at the position a on the smaller angle side, and the angle is relatively large. In other words, it is determined that the instruction unit 2-2 is located at a position b far away. Therefore, it is determined that a and b are real and a 'and b' are imaginary. If C2> C1, if the indication unit 2-1 is located at the position a ′ on the larger angle side and the indication unit 2-2 is located at the position b ′ where the angle is small and relatively far away, To be judged. As a result of comparing the central pixels in this way, two coordinates determined to be real are output. For example, out of the four circles described above, the center coordinates of the circles corresponding to a and b corresponding to the actual designated position are output.

  On the other hand, in S103, the combination of the number of signals received by each sensor unit 4 (the number of received light of the instruction unit 2-1 and the number of received light of the instruction unit 2-2) is (2, 1) or (1, If not (2) (NO in S103), the following processing is performed. That is, it is the case of a single input of (1, 1) or a plurality of inputs with no overlap in the received light information of (2, 2). First, in S107, the intermediate pixel of the rising and falling pixel information of the light quantity distribution signal corresponding to the detection threshold value V1 is derived for the light reception information of either of the sensor units 4-1 and 4-2. Then, an angle corresponding to the instruction unit 2 is calculated and output using a function of the pixel and the angle acquired in advance. Next, in S108, in the case of (1, 1), the coordinates of a single input are calculated. In the case of (2, 2), as described with reference to FIG. 9, four processes are performed by using a method of comparing the widths in the pixel direction, a method of comparing the light amount level of received light information, and the like. The true / false judgment is performed on the coordinate candidate points, and the real coordinates are calculated and output.

  As described above, in the present embodiment, the true / false determination is performed by comparing the center pixel due to the rising and falling due to the light reception information at a plurality of detection thresholds having different levels. For this reason, it is possible to accurately detect the coordinates of the pointing unit at the overlapping position from the sensor unit.

  In the above embodiment, the center pixel comparison method corresponding to different levels of detection thresholds is shown in S106. However, the present invention is not limited to this as long as it can discriminate the reflected light of different received light levels at the designated position 2 with different distances from the sensor unit 4 based on the difference of the corresponding pixel information instead of the light quantity level. For example, the true / false determination may be made by comparing falling pixels and rising pixels of detection thresholds of different levels and comparing the differences.

  Moreover, although this embodiment demonstrated the example in the case of implement | achieving the control apparatus which controls a coordinate input device by the exclusive arithmetic control circuit 5, an apparatus structure is not restricted to this. For example, a general-purpose information processing device or a programmable logic circuit may control the operation of the coordinate input device based on a computer program.

<< Embodiment 2 >>
Next, a coordinate input device according to a second embodiment (Embodiment 2) of the present invention will be described. In the first embodiment, an example has been described in which the true / false determination is performed by comparing the central pixels corresponding to the detection thresholds at different levels when light reception is duplicated in one sensor unit at the time of two inputs. However, the present invention is not limited to this as long as it is a method that can discriminate the reflected light of different light receiving levels by the indicator 2 having different distances from the sensor unit 4 based on the difference in pixel information. For example, the center pixel of the rising and falling pixels sliced by the detection threshold having the same level as the detection threshold V1 of the first embodiment is obtained, and this center pixel is compared with the peak pixel of the light reception level to determine the true / false. Also good.

  FIG. 11 is a diagram showing light reception information for explaining the true / false determination performed in the present embodiment. Unlike the first embodiment, in the processing in the present embodiment, the detection threshold value V1 of the present embodiment is set to a relatively low value that is substantially the same level as the detection threshold value V1 used in the first embodiment. Further, pixel detection at the peak position P at which the level is maximum is performed on the received light distribution information. This process is applied only when the received light information of the different reflected lights of the instruction units 2 having different distances in FIG.

  FIG. 12 is a flowchart showing a processing procedure of the truth determination processing in the present embodiment. In FIG. 12, processes other than S106 referred to in the first embodiment are the same as those in FIG. 6, and therefore only S106 will be described. For example, when the received light information of the different reflected lights of the instruction units 2 having different distances in FIG. 11A overlaps and the number of signals is 1, the process of S106 is performed. Each step of FIG. 12 is also executed based on the control of the arithmetic control circuit 5.

  In S106, the pixel P at the peak position and the center pixel C at the detection threshold V1 are compared, and the true / false determination is performed based on the comparison result. As shown in FIG. 11A, the rising and falling pixel information sliced at the detection threshold V1 is reflected by the reflected light of the indicating unit 2-1 at the position a and the reflected light of the indicating unit 2-2 at the position b. This is due to the overlapped light reception information. Here, the pixel width formed by rising and falling is W, and the center pixel is C as described above. On the other hand, the pixel P at the peak position where the detected light reception level is the maximum is based on the light reception information of the reflected light only of the reflected light of the indication unit 2-1 at the position a, as shown in FIG. is there. The reflected light from the instruction unit 2-1 at the position a has a higher light reception level because the distance from the sensor unit 4-1 is shorter than the instruction unit 2-2 at the position b. Therefore, the pixel P at the peak position where the light reception level is maximum is due to the reflected light from the indication unit 2-1 at the position a.

  Here, the pixel numbers of the peak pixel P and the center pixel C are compared. In the case of the positional relationship of FIG. 1, as shown in FIG. 4A, P <C, the indication unit 2-1 is located at the position a on the smaller angle side, and the angle is large and relatively far away b It is determined that the instruction unit 2-2 is located at the position. Therefore, it is determined that a and b are real and a 'and b' are imaginary. If P> C, the indication unit 2-1 is located at a relatively close position a ′ on the larger angle side of FIG. 1, and the indication unit 2- is located at a relatively small position b ′. 2 is determined to be located. Then, as a result of comparing the peak pixel and the center pixel, two coordinates determined to be real are output.

  As described above, in this embodiment, the true / false determination is made based on the positional relationship between the light receiving pixel corresponding to the peak of the light receiving distribution in which the reflected light from the plurality of instruction units overlaps and the light receiving pixel corresponding to the low light amount level. I do. For this reason, even if it is a case where the light reception distribution in a light-receiving part overlaps, without providing a special structure, they can be isolate | separated and a truth can be determined appropriately and the coordinate of an instruction | indication position can be acquired correctly. Therefore, it can be configured with a single-unit simple sensor unit, and it can accurately determine true or false even in the situation where the received light information overlaps without the burden of prior coordinate calculation processing, and highly accurate coordinate detection is possible. It becomes possible.

<< Other Embodiments >>
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

1: Coordinate input surface, 2: Instruction unit, 3: Coordinate input device, 4: Sensor unit, 5: Arithmetic control circuit, 6: Drive unit, 7: Light emission source, 8: Light receiving optical system, 9: Imaging device, 10 : Sensor substrate, 11: Coordinate operation circuit unit, 12: Projection drive circuit unit, 13: Interface circuit unit

Claims (12)

A coordinate input device for detecting a designated position with respect to an input surface,
A light projecting unit that projects light onto the input surface, and a light receiving unit that includes a plurality of light receiving pixels that receive reflected light reflected by the projecting unit instructed on the input surface. First and second sensor units;
An acquisition unit that detects a direction of an instruction by the instruction unit based on a received light distribution of the reflected light in the light receiving unit for each of the first and second sensor units, and acquires an instruction position by the instruction unit based on the direction. And
The acquisition unit specifies a light receiving pixel corresponding to the first and second light amount levels when a light reception distribution due to reflected light from a plurality of instruction units overlaps in any one of the light receiving units. A coordinate input device that discriminates the truth of a plurality of coordinate candidate points based on a positional relationship between a light receiving pixel corresponding to a light amount level and a light receiving pixel corresponding to a second light amount level. The second light level is greater than the first light level;
2. The apparatus according to claim 1, further comprising: a determination unit configured to determine whether or not light reception distributions by reflected light from a plurality of instruction units overlap based on the number of light receiving pixels corresponding to the first light amount level. The coordinate input device described in 1.   Two light receiving pixels adjacent to each other, wherein the light receiving amount of one light receiving pixel is smaller than the first light amount level, and the light receiving amount of the other light receiving pixel is based on the light receiving pixels larger than the first light amount level. The coordinate input device according to claim 2, further comprising a specifying unit that specifies a light receiving pixel corresponding to the first light amount level. Each of the plurality of light receiving pixels of the light receiving unit corresponds to an angle viewed from the light receiving unit,
When the light reception distribution due to the reflected light from the plurality of instruction units overlaps in one of the light receiving units, the obtaining unit sets the angle of one of the two light receiving pixels corresponding to the first light amount level in the light receiving unit. The center of the circle inscribed in the corresponding one straight line and the two straight lines corresponding to the angles of the two light receiving pixels corresponding to the first light quantity level in the other light receiving unit is acquired as the coordinate candidate point. The coordinate input device according to claim 3.   The coordinate input according to claim 3, wherein the acquisition unit detects a direction of the instruction unit viewed from the light receiving unit based on a center of a light reception distribution in the light receiving unit by reflected light from the instruction unit. apparatus.   The acquisition means, when a light reception distribution by reflected light from a plurality of instruction means overlaps in one of the light receiving sections, based on a light reception level of the light reception distribution in the other light receiving section, the truth of the plurality of coordinate candidate points The coordinate input device according to any one of claims 3 to 5, wherein the coordinate input device is discriminated.   The specifying means includes two light receiving pixels adjacent to each other, the light receiving amount of one light receiving pixel is smaller than the second light amount level, and the light receiving amount of the other light receiving pixel is smaller than the second light amount level. The coordinate input device according to any one of claims 3 to 6, wherein a light receiving pixel corresponding to the second light quantity level is further specified based on a large light receiving pixel.   8. The light receiving level according to claim 1, wherein the second light amount level is a light receiving level corresponding to a peak of a light receiving distribution in which reflected light from the plurality of instruction means overlaps. Coordinate input device. A coordinate input device for detecting a designated position with respect to an input surface,
A light projecting unit that projects light onto the input surface, and a light receiving unit that includes a plurality of light receiving pixels that receive reflected light reflected by the projecting unit instructed on the input surface. First and second sensor units;
For each of the first and second sensor units, a direction of an instruction by the instruction unit is detected based on a peak of a light reception distribution of the reflected light in the light receiving unit, and an instruction position by the instruction unit is acquired based on the direction. Acquisition means,
The acquisition means includes
When the light reception distribution due to the reflected light from the plurality of instruction means overlaps in any of the light receiving units, the overlapping light reception distribution is reflected from each of the plurality of instruction means based on the shape of the overlapped light reception distribution. Separating means for separating light into a light-receiving distribution;
A coordinate input device comprising: discrimination means for discriminating the truth of a plurality of coordinate candidate points based on the separated received light distribution. A light projecting unit that projects light onto the input surface; and a light receiving unit that includes a plurality of light receiving pixels that receive the reflected light reflected from the light projected by the instruction unit instructed on the input surface. 1. A control device that controls a coordinate input device that includes a second sensor unit and detects an indicated position with respect to an input surface,
Detecting means for detecting a direction of an instruction by the instruction means based on a received light distribution of the reflected light in the light receiving unit for each of the first and second sensor units;
Obtaining means for obtaining a position indicated by the instruction means based on the direction;
When the light reception distribution by the reflected light from the plurality of instruction means overlaps in any of the light receiving units, the light receiving pixels corresponding to the first and second light quantity levels are specified, and the first light quantity level is handled. A control device that determines the true or false of a plurality of coordinate candidate points based on a positional relationship between a light receiving pixel and a light receiving pixel corresponding to a second light amount level. A light projecting unit that projects light onto the input surface; and a light receiving unit that includes a plurality of light receiving pixels that receive the reflected light reflected from the light projected by the instruction unit instructed on the input surface. 1. A control method for controlling a coordinate input device that includes a second sensor unit and detects an indicated position with respect to an input surface,
A detecting step of detecting, for each of the first and second sensor units, a direction of an instruction by the instruction unit based on a received light distribution of the reflected light in the light receiving unit;
An acquisition unit comprising: an acquisition step of acquiring a position indicated by the instruction unit based on the direction;
In the acquisition step, when the light reception distribution due to the reflected light from the plurality of instruction means overlaps in any of the light receiving units,
A specifying step for specifying the light receiving pixels corresponding to the first and second light intensity levels;
And a determination step of determining the reality of the plurality of coordinate candidate points based on the positional relationship between the light receiving pixels corresponding to the first light amount level and the light receiving pixels corresponding to the second light amount level. Control method to do.   A computer program for causing a computer to function as each means included in the control device according to claim 10.

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