JP2011258102A - Input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an input device that solves a problem that, in the FTIR method, scattering angle characteristics of a scatterer causes the intensity difference of infrared light detected at a contact location, which results in reduction of the input accuracy.SOLUTION: An input device 1 detects a state in which a scatterer 7 contacts with a contact surface 2a of a transparent plate 2 capable of wave-guiding a light into the inside thereof by an image on the contact plate 2a which is imaged by using scattering light generated by the scatterer 7, after correcting, by a correction processing part 9, unevenness of a detection light intensity due to a difference of a contact location caused by scattering characteristics of the scatterer 7.

Description

  The present invention relates to an input device, and in particular, a contact surface in which a scatterer is in contact with a contact surface of a transparent or semi-transparent waveguide capable of guiding light therein, and is imaged using scattered light generated by the scatterer. The present invention relates to an input device that detects an image of the above.

FTIR (Frustrated
A technology that realizes information input to a computer by applying the phenomenon called “Total Internal Reflection” has been proposed. Scatterer (scattering material) that scatters light when irradiated with infrared light from the end face of a transparent plate such as an acrylic panel and guided in a way that confines infrared light inside the transparent plate due to total reflection. Is brought into contact with the transparent plate, a phenomenon occurs in which a part of the infrared light is scattered outside the transparent plate at the contact portion. This phenomenon is FTIR. By detecting infrared light scattered outside the transparent plate with a camera, it is possible to detect the contact state (contact area, shape, etc.) of the scatterer with the transparent plate.

  Non-Patent Document 1 and Non-Patent Document 2 describe examples of input devices using the FTIR method. Non-Patent Document 1 proposes a method of estimating the touch pressure from the area of the contact area between the finger and the panel at the time of touch detected by the FTIR method. Further, Non-Patent Document 2 proposes a method for distinguishing between the type of finger, the touch direction, and the like based on the image shape of the touched contact area detected by the FTIR method. These provide an input device to a computer that can identify a complex touch operation on the premise that the contact state of the scatterer with the transparent plate can be accurately detected by using FTIR.

  Another example of an input device using the FTIR method is described in Patent Document 1. The input device described in Patent Literature 1 includes a light guide plate, a plurality of light emitting elements, a plurality of light receiving elements, and a control unit. The light guide plate has a touch area, and generates scattered light according to contact with the touch area by a contact object. The plurality of light emitting elements are arranged at equal intervals on the side end surface of one side of the light guide plate, and irradiates light into the light guide plate. The plurality of light receiving elements are arranged at equal intervals on the side of the light guide plate perpendicular to the side on which the plurality of light emitting elements are arranged, and receive scattered light in the light guide plate. The control means performs lighting scanning for partially lighting the plurality of light emitting elements. Further, the control means moves from the coordinates when the scattered light is received by the light receiving element (Y coordinate) and the coordinates of the light emitting element that has been lit and scanned when the light receiving element is received (X coordinate) to the touch area by the contact object. Specify the input position.

  On the other hand, Patent Document 2 describes an example of a technique for correcting an image when processing an image captured by a camera. Patent Document 2 proposes a method of adjusting optical distortion and positional deviation of a stereo camera by image processing by converting each of a pair of image data output from the stereo camera using parameters. ing.

JP 2009-223535 A JP 2004-132870 A

Maki Naito, Buntaro Shizuki, Jiro Tanaka “Basic Study on Push-in Operation Using Contact Area in Infrared Touch Panel” Proceedings of IPSJ National Convention, Vol. 71, NO. 4, pp. 173-174, 2009 FengWang, Xiangshi Ren, “Empirical evaluation for fingerinput properties in multi-touch interaction”, Proceedingsof the 27th international conference on Human factors in computing systems, pp. 1063-1072, April 2009

  As described above, various input devices using the FTIR method have been proposed. By applying these techniques and detecting the contact state of the user's finger, for example, it is possible to realize a touch interface device that detects a user's touch operation on the display. In addition, since ink used for general marker pens also has a characteristic as a scatterer, it is possible to detect the application state of the ink on the transparent plate. Therefore, it is possible to realize a digital whiteboard that captures drawing information drawn with a marker pen on a display or the like into a computer.

  However, infrared light guided in a transparent plate such as an acrylic plate is usually scattered at different intensities in different directions. Such a characteristic is called a scattering angle characteristic. For this reason, even if the contact state of a scatterer and a panel is the same, a difference will arise in the intensity | strength of the scattered light detected according to the positional relationship of a scatterer and a camera. In addition, since the angle difference with respect to a camera becomes large as the scatterers located on the transparent plate at a distance from each other, the difference in the detection intensity of the scattered light becomes large.

  The influence of this scattering angle characteristic will be specifically described with reference to FIG. FIG. 1 shows a configuration example of an input device that detects a contact state of a scatterer using FTIR. Infrared light output from the light source is guided in the transparent plate by a total reflection phenomenon. Then, the infrared light is scattered outside the transparent plate because the total reflection phenomenon is lost at the place where the scatterer (1) and the scatterer (2) are in contact with the transparent plate, and is detected by the detection unit (detected). Light (1) and detected light (2)). The scatterer (1) and the scatterer (2) are the same substance, and the states (volume, mass, contact area with the transparent plate, etc.) other than the position on the transparent plate are the same. As shown in FIG. 1, since scattered light (1) and scattered light (2) are generated at different intensities in different directions, the intensity of the detected light detected by the detector is: detected light (1)> detected It becomes detection light (2). In the example of FIG. 1, the example in which the camera is disposed above the panel is shown, but the same phenomenon occurs when the camera is disposed below the panel.

  As described above, in the FTIR, even if the contact state between the transparent plate and the scatterer is the same, an intensity difference occurs in the infrared light detected by the contact position due to the scattering angle characteristic of the scatterer. Such a phenomenon causes a significant problem particularly when a contact state is detected in a wide imaging range using a camera equipped with a wide-angle lens. That is, there is a problem that the contact state of the scatterer cannot be accurately detected over a wide range using FTIR. As a result, when the pressure or the finger type is determined according to the area of the contact area with the panel, there is a risk of causing erroneous recognition. Further, when drawing information drawn with a marker pen on a display or the like is taken into a computer, it is impossible to accurately take in the thickness or darkness of the drawn line.

  For example, Patent Document 2 adjusts optical distortion and positional deviation of a camera by image processing when processing an image captured by the camera. However, the variation in detected light intensity due to the scattering angle characteristic of the scatterer is not eliminated even if the optical distortion or positional deviation of the camera is adjusted.

  The present invention has been proposed in view of such circumstances, and the purpose of the FTIR method is to produce a difference in intensity in the infrared light detected by the contact position due to the scattering angle characteristics of the scatterer. An object of the present invention is to provide an input device that solves the problem that the input accuracy is reduced due to the cause.

  An input device according to an aspect of the present invention captures an image of a state in which a scatterer is in contact with a contact surface of a transparent or translucent waveguide capable of guiding light therein by using scattered light generated by the scatterer. An input device for detecting from the image of the contact surface that has been corrected, comprising correction means for correcting variations in detected light intensity due to a difference in contact position caused by scattering characteristics of the scatterer.

  Since the present invention has such a configuration, even if an intensity difference occurs in the infrared light detected by the contact position due to the scattering angle characteristic of the scatterer, the correction is corrected by the correction means, so that the input accuracy is reduced. Can be prevented.

It is the figure shown about the specific example in case a difference arises in the intensity | strength in which scattered light is detected by the difference in the contact position of a scatterer in FTIR. It is a block diagram of a 1st embodiment of the present invention. It is a flowchart which shows the operation | movement of the calibration process in the 1st Embodiment of this invention. It is an example of the scattering characteristic data obtained by the calibration process in the 1st Embodiment of this invention. It is an example of the correction parameter in the 1st Embodiment of this invention. It is a figure which shows the example of the coordinate system of the image which the detection part in the 1st Embodiment of this invention acquires. It is the figure which showed the example of the information displayed on a display part by the calibration process in the 1st Embodiment of this invention. It is the figure which showed the other example of the information displayed on a display part by the calibration process in the 1st Embodiment of this invention. It is a figure which shows the example of the coordinate system of the image which the detection part in the 1st Embodiment of this invention acquires. It is a flowchart which shows the operation | movement of the correction process in the 1st Embodiment of this invention. It is an example of the graph which shows the relationship between the detection intensity | strength and correction value in the 1st Embodiment of this invention. It is a block diagram of the 2nd Embodiment of this invention. It is the figure which showed the condition at the time of making only one light source part in the 2nd Embodiment of this invention light-emit. It is the figure which showed the condition at the time of making only the other light source part in the 2nd Embodiment of this invention light-emit. It is the figure which showed the condition at the time of making only one light source part in the 2nd Embodiment of this invention light-emit, and moving a scatterer. It is a flowchart which shows the operation | movement of the correction | amendment process in the 2nd Embodiment of this invention. It is the figure which showed the example of the graph used when selecting the correction parameter in the 2nd Embodiment of this invention. It is the figure which showed the example which changes the irradiation angle of the infrared light to the transparent plate of the light source part in the 2nd Embodiment of this invention. It is the figure which showed the example which changes the imaging angle of the detection part in the 2nd Embodiment of this invention.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
Referring to FIG. 2, the input device 1 according to the first embodiment of the present invention includes a transparent plate 2, a light source unit 3, a detection unit 4, a display unit 5, and a processing unit 6.

  The transparent plate 2 confines and guides infrared light emitted from the light source unit 3 inside the plate, and the plate surface is used as a contact surface 2a of a scatterer 7 such as ink or a finger. The transparent plate 2 can be a transparent acrylic panel or glass. In the present embodiment, the waveguide is constituted by the transparent plate 2, but the waveguide may be constituted by a translucent acrylic panel or the like.

  The light source unit 3 is a light source for irradiating the side end surface of one side of the transparent plate 2 with infrared light. As the light source unit 3, for example, an electronic circuit board in which a plurality of infrared light emitting diodes (LEDs) are arranged on a straight line at almost equal intervals can be used.

  In order to detect the contact state of the scatterer 7, the detection unit 4 captures an image of the contact surface 2 a of the transparent plate 2 from above obliquely using infrared light. The detection unit 4 may be, for example, a digital camera equipped with a CCD image sensor that photoelectrically converts the brightness of light incident through a lens and a visible light cut filter into the amount of charge.

  The display unit 5 is a display device that displays information output from the processing unit 6. For example, a liquid crystal display or a projector can be used as the display unit 5. The display unit 5 is arranged so that its display surface faces the surface opposite to the contact surface 2 a of the transparent plate 2. Information displayed on the display surface of the display unit 5 can be viewed through the transparent plate 2. Visible light emitted from the display unit 5 also reaches the detection unit 4 via the transparent plate 2, but this does not appear in the imaging result because it is blocked by the visible light cut filter.

  The processing unit 6 includes a calibration processing unit 8, a correction processing unit 9, a correction parameter storage unit 10, and one or a plurality of application execution units 11. As the processing unit 6, for example, a general-purpose operating system or a computer such as a personal computer capable of operating application software can be used. In this case, the calibration processing unit 8, the correction processing unit 9, and the application execution unit 11 can be realized by a computer and a program that operates on the computer. The correction parameter storage unit 10 can be realized by a computer memory or a hard disk.

  The calibration processing unit 8 performs processing for generating correction parameters for correcting variations in detected light intensity due to the difference in contact position caused by the scattering characteristics of the scatterer 7.

  The correction parameter storage unit 10 records the correction parameters calculated based on the scattering characteristics of the scatterer. Note that this correction parameter is stored for each type of scatterer because it differs for each type of scatterer such as finger or ink.

  The correction processing unit 9 corrects the pixel value of the image in the contact state detected by the detection unit 4 using the correction parameter stored in the correction parameter storage unit 10. That is, the correction processing unit 9 corrects the variation in detected light intensity due to the difference in contact position caused by the scattering characteristics of the scatterer.

  The application execution unit 11 is prepared for each type of application such as touch detection and drawing information recording. Each application execution unit 11 receives the image corrected by the correction processing unit 9 as input information, and the scatterer 7 comes into contact with the contact surface 2a by, for example, quantizing the pixel value of each pixel with a threshold value. Pixels that are not in contact with each other and pixels that are not in contact with each other are detected, and based on the detection result, the processing result corresponding to each application is displayed on the display unit 5. For example, the application execution unit 11 for touch detection recognizes the contact position of the user's finger and displays a cursor image or the like on the display unit 5 as shown in the display example in the display unit 5 of FIG. For example, the application execution unit 11 for recording drawing information displays the detected ink application area as drawing information to be taken into a computer.

[Description of operation]
Next, the overall operation of the present embodiment will be described in detail. The entire process of the present embodiment is a calibration process for acquiring correction parameters necessary for executing the correction process in advance, and the image acquired by the detection unit 4 is corrected based on the correction parameters. For this reason, the application execution unit 11 receives the corrected image as input information and performs a process according to the application. Since the process performed by the last application execution unit 11 varies depending on the application such as touch detection and recording of drawing information, detailed description thereof is omitted in the present embodiment.

  First, the calibration process will be described in detail with reference to the drawings.

  FIG. 3 is a flowchart showing the overall operation of the calibration process. FIG. 4 is an example of scattering characteristic data acquired by the calibration process. In the example of FIG. 4, the vertical axis represents the detection intensity (pixel value (for example, luminance value)) at an arbitrary pixel of the image. The horizontal axis corresponds to the X coordinate in FIG. That is, in this embodiment, a certain angle of the contact surface 2a of the rectangular transparent plate 2 is set as the origin, one side of the transparent plate 2 extending therefrom is set as the X axis, and the other side is set as the Y axis. The acquired data in FIG. 4 indicates each detection intensity for each detection position on the transparent plate 2 of the image acquired by the detection unit 4. The acquired data in FIG. 4 is obtained by causing the user to perform an operation of bringing the scatterer into contact with a plurality of positions on a specific straight line on the transparent plate 2 parallel to the X axis.

  First, the calibration processing unit 8 displays a start menu for instructing the user to perform a calibration operation through the screen of the display unit 5 (Step 1 in FIG. 3). FIG. 7 shows an example of the start menu. In this example, it is assumed that the scatterer 7A is the ink of the marker pen 12. As shown in FIG. 7, the calibration processing unit 8 displays a message “Please trace this line” on the display unit 5 and applies ink when the user performs the calibration operation. The area to be displayed is displayed as the calibration area 13. Such a display allows the user to know where to apply the ink, so that the calibration operation can be performed easily and reliably. The message is not limited to the above example. For example, “Please trace this line with almost the same force”, “Please trace this line at a constant speed”, etc.

  Next, the calibration processing unit 8 measures the detection intensity using the detection unit 4 (Step 2). Specifically, the calibration processing unit 8 measures the detection intensity (pixel value) for each coordinate on the calibration area 13 from the captured image of the transparent plate 2 captured by the detection unit 4. Before measuring the detection intensity, the calibration processing unit 8 applies a lens to the captured image in accordance with various conditions such as the camera used in the detection unit 4, the imaging angle, and the influence of noise light such as external light. Processing such as distortion correction, trapezoidal distortion correction, and threshold processing may be performed.

  The process of Step 2 in FIG. 3 is repeatedly executed until the detection intensity can be acquired in all areas in the calibration area 13. The calibration area 13 may be the entire area of the contact surface 2a of the transparent plate 2 or may be limited to a part of the contact surface 2a. In the present embodiment, it is assumed that the scattered light intensity can be regarded as almost the same even if there is a difference in the Y coordinate value if the X coordinate value is the same. For this reason, a stripe-shaped calibration area 13 having a constant width in the Y-axis direction and extending in the X-axis direction is set. In this case, the value of the correction parameter is stored corresponding to each value of the X coordinate value.

  If the detected intensity can be acquired within the specified range, the calibration processing unit 8 converts the acquired data into a correction parameter and stores it in the correction parameter storage unit 10 (Step 3). Specifically, the calibration processing unit 8 first calculates an average value of all acquired detection intensities. Next, for each position where the detected intensity is acquired, the reciprocal of the ratio of the detected intensity at the position to the average value is calculated, and this calculated value is used as the value of the correction parameter at the position. The above ratio may be used as the value of the correction parameter instead of the reciprocal. FIG. 5 shows an example of the calculated correction parameter. In this example, each detected intensity for each X coordinate is converted into a reciprocal of the ratio to the average value of all data and stored. When the calibration processing unit 8 finishes calculating and storing the correction parameter, the calibration processing unit 8 displays a message indicating the end of the calibration processing to the user through the display unit 5 and ends the calibration processing (Step 4).

  In order to obtain an accurate correction parameter in the calibration process, it is important that there is no variation in the contact state of the scatterer placed at each detection position. Therefore, the calibration processing unit 8 may execute the calibration processing as described above a plurality of times, take an average of the acquired data obtained each time, and calculate a correction parameter based on the average. In addition, the calibration processing unit 8 performs a drawing operation on the calibration area 13 by the user at a constant speed so that the user can apply the ink of the marker pen at a constant pressure, for example, as shown in FIG. You may make it display the animation 14 induced | guided | derived to 2 on the display part 5. FIG. At that time, as shown in FIG. 8, a message such as “Please trace this line along with the animation of the arrow” may be displayed on the display unit 5 at the same time. Note that the display object for guiding to a constant speed is not limited to the arrow. For example, a predetermined mark or symbol may be used.

  In the above example, the case where the scatterer is the ink of the marker pen is shown. However, even when the scatterer is the finger of the user, the drawing with the marker pen is replaced with the action of tracing with the finger, and the same as above. The correction parameter can be acquired and stored by this method.

  Next, processing for correcting the image acquired by the detection unit 4 using the generated correction parameter will be described. As an example, the detection unit 4 captures an image of the transparent plate 2 from coordinates (0, 0) to (Width, Height) as shown in FIG. 9, and the correction processing unit 9 performs correction processing on the acquired image. An example of the execution will be described in detail with reference to the drawings. Further, it is assumed that the scatterer to be used is ink, and only the correction parameters for ink are stored in the correction parameter storage unit 10. When correction parameters for one or more other types of scatterers are stored in the correction parameter storage unit 10 in addition to the correction parameters for ink, the user is allowed to select in advance which correction parameter to use. You may do it.

  FIG. 10 is a flowchart showing the operation procedure of the processing of the correction processing unit 9. FIG. 11 is a graph showing the relationship between the detection intensity (pixel value) of an arbitrary pixel of the acquired image and the value after correcting it based on the correction parameter. Hereinafter, for the sake of explanation, the coordinates of an arbitrary pixel of the image to be corrected are assumed to be (i, j).

  First, the correction processing unit 9 acquires a correction coefficient at X = i from the correction parameters in the correction parameter storage unit 10 (Step 11). This correction coefficient is determined by the value when the correction parameter coordinate X = i, as shown in the example of FIG.

  Next, the correction processing unit 9 acquires the detected intensity of the pixel coordinates (i, j) to be corrected (Step 12). Then, the correction processing unit 9 obtains a correction value by multiplying the detected intensity by the correction coefficient acquired in Step 11 (Step 13). Specifically, as shown in FIG. 11, p × d obtained by multiplying the detection intensity p of the coordinates (i, j) of the image to be corrected by the correction parameter d is a value obtained after correction.

  As shown in the flowchart of FIG. 10, the correction process is executed from the coordinates (0, 0) to (Width, Height) of the acquired image. Thereby, the correction of the detection intensity of all pixels is completed. As with the calibration process, the image before correction processing is converted into an image according to various conditions such as the camera used in the detection unit, the imaging angle, and the influence of noise light such as external light. On the other hand, processing such as lens distortion correction, trapezoidal distortion correction, and threshold processing may be performed.

  As described above, in the correction process, by correcting the value of each pixel of the image acquired by the detection unit 4 based on the correction parameter acquired in the calibration process, a difference in detection intensity due to the scattering characteristic can be eliminated. .

  As described above, in the present embodiment, the scattering characteristic data is acquired in advance by the calibration process for acquiring the scattering characteristic of the scatterer, and the image correction process is performed based on the correction parameter calculated based on this. Is configured to do. Therefore, it is possible to obtain an image in which a difference in detection intensity (pixel value) based on the influence of scattering characteristics is eliminated.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

  In the present embodiment, an example of processing in which a correction parameter is specified in real time and correction is performed while the user is performing an information input operation such as a touch operation with a finger or a drawing with a marker pen. Will be described.

  Referring to FIG. 12, in the input device 20 according to the present embodiment, the light source unit 3B is attached to the side opposite to the side of the transparent plate 2 to which the light source unit 3A corresponding to the light source unit 3 of FIG. And the point provided with the control part 21 which controls ON / OFF of light emission of these two light source parts 3A and 3B is different from 1st Embodiment. Moreover, a part of function of the correction | amendment process part 9 in the process part 6 differs from 1st Embodiment. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted. A correction parameter corresponding to a plurality of different types of scatterers is recorded in advance in the correction parameter storage unit 10 in the processing unit 6.

  Next, the operation in the present embodiment will be described in detail with reference to the drawings. First, when the control unit 21 captures an image on the transparent plate 2, only the light source unit 3A emits light, and when only the light source unit 3B emits light, the light source unit has different light emission conditions. Imaging is performed using the detection unit 4, and an image for each case is acquired. As a result, the same effect as when the position of the scatterer is changed in a pseudo manner can be obtained. Even if the position of the scatterer is not changed, the detection intensity is the same as when the scatterer is placed at multiple positions. Can be obtained. This will be described with reference to FIGS. 13, 14, and 15. FIG.

  FIG. 13 shows a situation where the scatterer on the transparent plate 2 scatters infrared light when only the light source unit 3 </ b> A is ON, and a part thereof is detected by the detection unit 4. FIG. 14 shows a situation where the light source unit 3A is turned off and the light source unit 3B is turned on. In this case, although the position of the scatterer does not change, the reflection angle of the infrared light guided in the transparent plate 2 changes, so that the intensity of the detected light changes depending on the scattering characteristics of the scatterer. This indicates that by switching ON / OFF of the light source unit 3A and the light source unit 3B, it is possible to reproduce a state in which detected light similar to that obtained when the position of the scatterer is moved as shown in FIG. .

  In the present embodiment, the distance L is measured to determine how much the intensity of the detected light, which is changed by switching between the light source unit 3A and the light source unit 3B, corresponds to when the scatterer is moved. Store it in the memory. In the present embodiment, the distance L is substantially the same regardless of the type of scatterer. Further, it is assumed that the scatterers are almost the same even if they are in different positions. If the distance L varies depending on the type of scatterer and the contact position of the scatterer, a plurality of distances L corresponding to the position of each scatterer and scatterer are recorded in advance, and the type of scatterer when executing the correction process The appropriate distance L is referred to according to the contact position.

  Next, an execution example of the correction process in the present embodiment will be described. As an example, another image obtained by switching the light source unit 3A to OFF and the light source unit 3B to ON for the detected image (1) captured with the light source unit 3A turned on and the light source unit 3B turned off. A case will be described in which the detection intensity after correction of each pixel is determined from (detected image (2)) and the detected image (1) is corrected.

  FIG. 16 is a flowchart showing the flow of correction processing in the present embodiment. In the present embodiment, for the sake of explanation, the same coordinate system as in FIG. 9 is used, and the coordinates of an arbitrary pixel of the image to be corrected are (i, j).

  First, the correction processing unit 9 acquires the detection intensity p1 of the pixel (i, j) in the detection image (1) when only one of the light sources 3A is turned on (Step 21). Next, the correction processing unit 9 acquires the detection intensity p2 of the same pixel in the detection image (2) when only the light source 3B is turned on (Step 22).

  Then, the correction processing unit 9 estimates an optimal correction parameter from the two detection intensities p1 and p2 (Step 23). This processing is performed in such a way that one of the correction parameter candidates of a plurality of different types of scatterers recorded in advance in the correction parameter storage unit 10 is estimated. It is assumed that the recorded correction parameters of each scatterer are stored in the same format as the correction parameter data shown in the first embodiment. With respect to the timing at which these are stored, the calibration processing shown in the first embodiment is performed on a plurality of different types of scatterers when the input device is shipped from the factory or when the input device is delivered for the first time. This is possible at various timings such as storing the acquired data.

  The correction processing unit 9 calculates the value at each detection position of the correction parameter of each scatterer with respect to the reciprocals m / p1 and m / p2 of the ratio to the average value, where m is the average value of the two values p1 and p2. Calculate the difference. FIG. 17 shows an example of a graph for comparing two data candidates of the correction parameter of the scatterer 7A and the correction parameter of the scatterer 7B. Specifically, m / p1 is obtained by the effect of shifting the detection position by the distance L by switching the light source with the value of the detected image (1) at the corresponding coordinate, and m / p2 with the value of the detected image (2). Value. Then, the correction processing unit 9 determines data having the smallest difference from each correction parameter data for each value as data used for the correction processing. In the example of FIG. 17, since the correction parameter of the scatterer 7A is smaller than that of the scatterer 7B, the correction parameter of the scatterer 7A is used.

  Next, the correction processing unit 9 corrects the detected intensity based on the selected correction parameter (Step 24). The specific processing of Step 24 is the same as the correction processing shown in the first embodiment, after correction by multiplying the pixel value of the coordinates (i, j) of the detected image (1) by the correction parameter. This is a process for obtaining the pixel value of.

  The above processing is executed from pixel coordinates (0, 0) to (Width, Height) as shown in the flowchart of FIG. Thereby, the correction of the detection intensity of all pixels is completed.

  In the present embodiment, as a method for switching the detection condition, a method for installing the light source units 3A and 3B that can be switched ON / OFF on both side surfaces of the transparent plate 2 has been described. This is an example of switching, and is not limited thereto. For example, as shown in FIG. 18, the light source units 3A and 3B having different incident angles are installed on the same side surface of the transparent plate 2 and the detection conditions are switched by alternately switching the ON / OFF thereof. It is. In addition, as shown in FIG. 19, there is a method in which a plurality of detection units 4A and 4B having different angles and attachment positions for imaging the contact surface of the transparent body 2 are prepared, and the detection conditions are switched by switching the plurality of detection units 4. Applicable. That is, the detection condition is switched by any one, two, or all of the incident angle of the light applied to the transparent plate 2, the position and direction of the detection unit 4 that captures the image of the contact surface of the transparent plate 2. It is possible to adopt a method of switching between.

  In addition to this, for example, correction parameters are generated from detection intensities at a plurality of positions obtained while the user is performing an input operation, thereby similarly correcting without requiring the user to perform a calibration operation. Processing can be executed.

  As described above, in the present embodiment, a user in advance is processed by a process of estimating a scatterer from a plurality of detection intensities obtained by switching a plurality of light source units or detection units and performing correction using the correction parameter. Thus, it is possible to obtain a corrected image in which the difference in detection intensity based on the influence of the scattering characteristics is eliminated without requiring the calibration operation by the above and the selection operation of the correction parameter to be used.

A part or all of the above embodiments can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1)
Input for detecting a state in which a scatterer is in contact with a contact surface of a transparent or translucent waveguide capable of guiding light inside from an image of the contact surface imaged using scattered light generated by the scatterer A device,
An input device comprising correction means for correcting variation in detected light intensity due to a difference in contact position caused by scattering characteristics of the scatterer.
(Appendix 2)
The correction means corrects the pixel value of the image of the contact surface using a correction parameter for correcting variation in detected light intensity due to a difference in contact position caused by scattering characteristics of the scatterer. The input device according to Supplementary Note 1, wherein the input device is characterized.
(Appendix 3)
Calibration processing means for calculating the value of the correction parameter by measuring the intensity of the scattered light for each of the plurality of positions from the image of the contact surface in contact with the scatterer at a plurality of positions. The input device according to appendix 2, characterized by:
(Appendix 4)
Correction parameter storage means for storing the correction parameter for each type of the scatterer,
The input device according to appendix 2 or 3, wherein the correction unit selects the correction parameter to be used for actual correction from the plurality of correction parameters stored in the correction parameter storage unit.
(Appendix 5)
The correction means uses the correction parameter used for actual correction by utilizing the fact that the method of changing the light intensity at each position of the image of the contact surface imaged under different imaging conditions varies depending on the type of the scatterer. The input device according to appendix 4, wherein the input device is selected.
(Appendix 6)
The correction means sets the imaging condition of the image of the contact surface for detecting the state in which the scatterer is in contact as the first imaging condition, sets the imaging condition different from the first imaging condition as the second imaging condition, and Based on the light intensity under the first imaging condition and the light intensity under the second imaging condition, the correction parameter used for actual correction is selected from the plurality of correction parameters stored in the correction parameter storage means The input device according to appendix 4, wherein:
(Appendix 7)
The second imaging condition is any one of an incident angle of light applied to the waveguide by a light source unit that irradiates light to the waveguide, a position of a detection unit that captures an image of the contact surface, and an orientation. The input device according to appendix 5 or 6, wherein one, two, or all are different from the first imaging condition.
(Appendix 8)
The calibration processing means performs an operation of bringing the scatterer into contact with two or more positions on the contact surface simultaneously or sequentially on a display unit arranged so that a display surface overlaps the waveguide. 4. The input device according to appendix 3, wherein display for instructing is performed.
(Appendix 9)
The calibration processing means is configured to place the scatterer at two or more positions on the contact surface simultaneously or under the same or similar pressure on the display unit arranged so that the display surface overlaps the waveguide. 4. The input device according to appendix 3, wherein a display for instructing to perform operations in order is performed.
(Appendix 10)
The calibration processing means maintains a state in which the scatterer is brought into contact with the contact surface at a first position on a display unit arranged so that a display surface overlaps the waveguide. The input device according to appendix 3, wherein a display for instructing to perform an operation of moving the scatterer to a second position distant from the first position is performed.
(Appendix 11)
The calibration processing means maintains a state in which the scatterer is brought into contact with the contact surface at a first position on a display unit arranged so that a display surface overlaps the waveguide. The input device according to appendix 3, wherein a display for instructing an operation to move the scatterer to a second position separated from the first position is performed at a constant speed.
(Appendix 12)
The calibration processing means displays a graphic object that moves at a constant speed along a predetermined path on a display unit that is arranged so that a display surface overlaps the waveguide. The input device according to any one of the above.
(Appendix 13)
13. The input device according to any one of appendices 1 to 12, wherein the scatterer is ink.
(Appendix 14)
14. The input device according to any one of appendices 1 to 13, wherein the scatterer is a user's finger.
(Appendix 15)
The input according to any one of appendices 1 to 14, wherein the detected contact state is any one of or both of a contact area between the waveguide and the scatterer, and a shape of a contact surface. apparatus.
(Appendix 16)
A transparent or translucent waveguide having a contact surface for contacting the scatterer and capable of guiding light inside;
A light source unit for irradiating infrared light onto the side surface of the waveguide;
A detection unit that captures an image of the contact surface with which the scatterer comes into contact from above or below the waveguide using scattered light generated by the scatterer;
A variation in detected light intensity due to a difference in contact position caused by a scattering characteristic of the scatterer on the image of the contact surface is corrected, and the scattering is applied to the contact surface from the image of the contact surface after the correction. An input device comprising: a processing unit that detects a state of contact with a body.
(Appendix 17)
An input method executed by an input device having a contact surface for contacting a scatterer and having a transparent or translucent waveguide capable of guiding light inside, a detection unit, and a processing unit. ,
The detection unit captures an image of the contact surface with which the scatterer contacts, using scattered light generated by the scatterer,
The input method, wherein the processing unit corrects variation in detected light intensity due to a difference in contact position caused by a scattering characteristic of the scatterer on an image of the contact surface.
(Appendix 18)
A computer that constitutes the processing unit of an input device having a contact surface for contacting a scatterer and having a transparent or translucent waveguide capable of guiding light inside, a detection unit, and a processing unit ,
Detected light intensity due to a difference in contact position caused by scattering characteristics of the scatterer on an image of the contact surface on which the scatterer is imaged by the detection unit using scattered light generated by the scatterer An input program for functioning as a correction means for correcting variations in the image.

DESCRIPTION OF SYMBOLS 1 Input device 2 Transparent board 2a Contact surface 3 Light source part 4 Detection part 5 Display part 6 Processing part 7 Scattering body 8 Calibration processing part 9 Correction processing part 10 Correction parameter memory | storage part 11 Application execution part 20 Input device 21 Control part

Claims (10)

Input for detecting a state in which a scatterer is in contact with a contact surface of a transparent or translucent waveguide capable of guiding light inside from an image of the contact surface imaged using scattered light generated by the scatterer A device,
An input device comprising correction means for correcting variation in detected light intensity due to a difference in contact position caused by scattering characteristics of the scatterer.   The correction means corrects the pixel value of the image of the contact surface using a correction parameter for correcting variation in detected light intensity due to a difference in contact position caused by scattering characteristics of the scatterer. The input device according to claim 1.   Calibration processing means for calculating the value of the correction parameter by measuring the intensity of the scattered light for each of the plurality of positions from the image of the contact surface in contact with the scatterer at a plurality of positions. The input device according to claim 2. Correction parameter storage means for storing the correction parameter for each type of the scatterer,
The input device according to claim 2, wherein the correction unit selects the correction parameter to be used for actual correction from the plurality of correction parameters stored in the correction parameter storage unit. .   The correction means uses the correction parameter used for actual correction by utilizing the fact that the method of changing the light intensity at each position of the image of the contact surface imaged under different imaging conditions varies depending on the type of the scatterer. The input device according to claim 4, wherein the input device is selected.   The correction means sets the imaging condition of the image of the contact surface for detecting the state in which the scatterer is in contact as the first imaging condition, sets the imaging condition different from the first imaging condition as the second imaging condition, and Based on the light intensity under the first imaging condition and the light intensity under the second imaging condition, the correction parameter used for actual correction is selected from the plurality of correction parameters stored in the correction parameter storage means The input device according to claim 4, wherein:   The second imaging condition is any one of an incident angle of light applied to the waveguide by a light source unit that irradiates light to the waveguide, a position of a detection unit that captures an image of the contact surface, and an orientation. The input device according to claim 5, wherein one, two, or all are different from the first imaging condition.   The calibration processing means performs an operation of bringing the scatterer into contact with two or more positions on the contact surface simultaneously or sequentially on a display unit arranged so that a display surface overlaps the waveguide. The input device according to claim 3, wherein a display for instructing is performed. An input method executed by an input device having a contact surface for contacting a scatterer and having a transparent or translucent waveguide capable of guiding light inside, a detection unit, and a processing unit. ,
The detection unit captures an image of the contact surface with which the scatterer contacts, using scattered light generated by the scatterer,
The input method, wherein the processing unit corrects variation in detected light intensity due to a difference in contact position caused by a scattering characteristic of the scatterer on an image of the contact surface. A computer that constitutes the processing unit of an input device having a contact surface for contacting a scatterer and having a transparent or translucent waveguide capable of guiding light inside, a detection unit, and a processing unit ,
Detected light intensity due to a difference in contact position caused by scattering characteristics of the scatterer on an image of the contact surface on which the scatterer is imaged by the detection unit using scattered light generated by the scatterer An input program for functioning as a correction means for correcting variations in the image.

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