JP3161860U - Electronic pen and information processing system - Google Patents

Abstract

An electronic pen and an information processing system capable of appropriately recognizing both an encoded pattern printed with an infrared absorbing ink and an encoded pattern printed with an infrared reflective ink are proposed. An electronic pen performs binarization processing on a captured image captured by irradiating infrared rays on a sheet on which a coding pattern is formed, and determines an infrared reflection region and an infrared absorption region, The magnitude relationship between the area of the infrared reflection area and the area of the infrared absorption area is compared. Then, the electronic pen performs a negative / positive inversion process on the binarized image according to the comparison result, and when the negative / positive inversion process is performed, an encoding pattern is generated based on the image subjected to the negative / positive inversion process. If the negative / positive inversion process is not performed, the coding pattern is recognized based on the binarized image. [Selection] Figure 1

Description

  The present invention relates to an electronic pen and an information processing system for recognizing an encoding pattern formed on a sheet.

  In recent years, electronic pens that digitize written information have been developed, and “Anoto pen” developed by Swedish company Anoto is known as a representative example. Anotopen is used with dedicated paper on which a predetermined dot pattern is printed. In addition to the usual ink cartridge for writing characters, etc., the anotopen has a small camera for capturing the dot pattern printed on the dedicated paper and the position coordinates on the dedicated paper from the captured dot pattern. A processor for calculating and a data communication unit for transmitting the calculated position coordinates and the like to an external device are mounted. When the user writes characters on the special paper with an anotopen or puts a check mark on the image designed on the special paper, the small camera captures the dot pattern printed on the special paper as the pen moves. The entry information such as characters and images written by the user is recognized from the continuous position coordinates calculated by the processor. The entry information is transmitted from the Anotopen to a nearby personal computer or a mobile phone or other terminal device by the data communication unit (see, for example, Patent Documents 1 and 2).

  In addition, Patent Document 3 proposes various dot pattern recognition methods using an electronic pen. Patent Document 4 proposes a technique in which a transparent sheet on which an infrared reflective transparent pattern is printed is used by mounting the transparent sheet on the surface or in front of the display device. Patent Document 5 proposes a technique of projecting a stroke written with an electronic pen on a screen on which a dot pattern is formed, onto a screen by a projector via a computer.

Japanese translation of PCT publication No. 2003-511761 Special table 2009-543181 Japanese Patent No. 4385169 JP 2007-323165 A No. 3151886 Publication

  As described above, conventionally, a sheet on which an encoding pattern is printed with an infrared absorbing ink and a sheet on which an encoding pattern is printed with an infrared reflective ink have been used. It has been difficult to properly recognize both such coding patterns.

  Therefore, the present invention proposes an electronic pen and an information processing system capable of appropriately recognizing both an encoded pattern printed with infrared absorbing ink and an encoded pattern printed with infrared reflective ink. To do.

  An electronic pen according to the present invention includes an infrared irradiation unit that irradiates infrared rays onto a sheet on which a coding pattern is formed, an imaging unit that images a region irradiated with infrared rays by the infrared irradiation unit, and the imaging unit. Binarization processing means for performing binarization processing on the captured image using a predetermined threshold; and an infrared reflection region and an infrared absorption region are determined from the binarized image, and the infrared reflection An area comparison unit that compares the size of the area and the area of the infrared absorption region, and a negative / positive inversion process that performs a negative / positive inversion process on the binarized image according to a comparison result by the area comparison unit When the negative / positive inversion processing is performed by the inversion processing means and the negative / positive inversion processing means, the coding pattern is based on the image subjected to the negative / positive inversion processing. An encoding pattern recognition unit that recognizes the encoding pattern based on the binarized image when the negative / positive inversion processing unit has not performed the negative / positive inversion processing. Is provided.

  The above electronic pen performs binarization processing on a captured image captured by irradiating infrared rays onto a sheet on which a coding pattern is formed, and discriminates infrared reflection regions and infrared absorption regions, thereby reflecting infrared rays. The size relationship between the area of the region and the area of the infrared absorption region is compared. Then, the electronic pen performs a negative / positive inversion process on the binarized image according to the comparison result, and when the negative / positive inversion process is performed, an encoding pattern is generated based on the image subjected to the negative / positive inversion process. If the negative / positive inversion process is not performed, the coding pattern is recognized based on the binarized image. This makes it possible to appropriately recognize both the coding pattern printed with the infrared absorbing ink and the coding pattern printed with the infrared reflective ink.

  In the above electronic pen, the area comparison unit determines the infrared reflection area and the infrared absorption area from a predetermined area of a part of the binarized image, and determines the area of the infrared reflection area and the infrared absorption area. Compare the size relationship with the area. Thereby, it is possible to speed up the processing with the electronic pen.

  In a preferred example, the sheet includes a sheet on which the coding pattern is printed with an infrared absorbing ink, and a sheet on which the coding pattern is printed with an infrared reflective ink.

  An information processing system according to the present invention is an information processing system including an electronic pen and a terminal device, and the electronic pen includes infrared irradiation means for irradiating infrared rays onto a sheet on which an encoded pattern is formed. An imaging unit that images an area irradiated with infrared rays by the infrared irradiation unit; and a transmission unit that transmits a captured image captured by the imaging unit to the terminal device. Receiving means for receiving the captured image transmitted from the transmitting means, binarization processing means for performing binarization processing on the captured image received by the receiving means using a predetermined threshold, and An area ratio for discriminating the infrared reflection area and the infrared absorption area from the binarized image and comparing the size relationship between the area of the infrared reflection area and the area of the infrared absorption area And negative / positive inversion processing means for performing negative / positive inversion processing on the binarized image in accordance with a comparison result by the region comparison means, and the negative / positive inversion processing is performed by the negative / positive inversion processing means. In this case, the coding pattern is recognized based on the image subjected to the negative / positive inversion processing, and when the negative / positive inversion processing is not performed by the negative / positive inversion processing means, Coding pattern recognition means for recognizing the coding pattern on the basis thereof. Also by the information processing system described above, it is possible to appropriately recognize both the coding pattern printed with the infrared absorbing ink and the coding pattern printed with the infrared reflective ink.

  In the information processing system, the area comparison unit determines the infrared reflection area and the infrared absorption area from a predetermined area of a part of the binarized image, and determines the area of the infrared reflection area and the infrared absorption area. It is preferable to compare the magnitude relationship with the area of the region. Thereby, it is possible to speed up the processing in the terminal device.

  In a preferred example, the sheet includes a sheet on which the coding pattern is printed with an infrared absorbing ink, and a sheet on which the coding pattern is printed with an infrared reflective ink.

  According to the present invention, it is possible to appropriately recognize both the coding pattern printed with the infrared absorbing ink and the coding pattern printed with the infrared reflective ink.

It is a system configuration figure of the information processing system in this embodiment. It is explanatory drawing which shows the relationship between the arrangement | positioning of the dot in a dot pattern, and the value converted. (A) shows a dot pattern typically, and (b) is a figure showing an example of information corresponding to it. It is the schematic which shows the structure of an electronic pen. It is a figure which shows typically the data structure of the entry information transmitted from an electronic pen to an external device terminal. It is a functional block diagram of an external device terminal. (A) shows an example of a binarized image on a sheet, and (b) shows an example of a binarized image on a transparent film. It is an entry information transmission process flow in this embodiment. It is an encoding pattern analysis transmission processing flow in the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[System configuration of information processing system]
As shown in FIG. 1, an information processing system 10 in this embodiment includes an electronic pen 1 used by a user, an external device terminal 2 that receives and processes entry information from the electronic pen 1, a sheet 3, and a transparent A film (in other words, a transparent sheet) 4. The external device terminal 2 is, for example, a computer device, a mobile phone, or a game machine. The transparent film 4 is affixed to the display 201 of the external device terminal 2. Such an information processing system 10 is suitably used for handwriting input to the external device terminal 2 by handwriting on the transparent film 4 with the electronic pen 1.

[Paper and transparent film]
First, the paper 3 and the transparent film 4 will be described. On the substantially entire surface of the paper 3 and the transparent film 4, an Anoto dot pattern (hereinafter also referred to as “encoding pattern”) indicating the position coordinates is printed. Specifically, the coding pattern is printed on the paper 3 with ink having infrared absorptivity (hereinafter, referred to as “infrared absorbing ink” as appropriate). For example, as the infrared absorbing ink, an ink containing carbon can be used. Further, the sheet 3 itself (in a state where the encoded pattern is not printed) does not have infrared absorptivity but has infrared reflectivity.

  On the other hand, a coding pattern is printed on the transparent film 4 with an ink having infrared reflectivity (hereinafter, referred to as “infrared reflective ink” as appropriate). For example, as the infrared reflective ink, the ink described in Patent Document 4 (Japanese Patent Laid-Open No. 2007-323165) described above can be used. Moreover, the transparent film 4 itself (state in which the coding pattern is not printed) has infrared absorptivity. In addition, when the surface plate of the display 201 is configured to have infrared absorptivity, the transparent film 4 itself may not have infrared absorptivity.

[Dot pattern]
Next, an Anoto dot pattern (encoded pattern) printed on the paper 3 and the transparent film 4 will be described. 2 and 3, for convenience of explanation, the dot part of the dot pattern is represented by black, and the part other than the dot is represented by white.

  FIG. 2 is a diagram for explaining the relationship between the dots of the dot pattern printed on the paper 3 and the transparent film 4 and the values to which the dots are converted. As shown in FIG. 2, each dot of the dot pattern is associated with a predetermined value depending on its position. In other words, each dot is associated with a value of 0 to 3 depending on which direction the top, bottom, left, or right is shifted from the reference position of the grid (intersection of the vertical line and horizontal line). The value of each dot can be further converted into a first bit value for the X coordinate and a second bit value for the Y coordinate. The position coordinates on the paper 3 or the transparent film 4 are determined by the combination of information thus associated.

  FIG. 3A shows an arrangement of a certain dot pattern. As shown in FIG. 3 (a), 6 × 6 dots within a range of about 2 mm in length and breadth form a unique pattern no matter where 6 × 6 dots are taken from any part on paper 3 or transparent film 4. Is arranged. The dot pattern formed by these 36 dots holds relative position coordinates on the paper 3 or the transparent film 4. FIG. 3B is a diagram in which each dot shown in FIG. 3A is converted into a value associated with the regularity shown in FIG. 2 according to the shift direction from the reference position of the lattice. This conversion is performed by the electronic pen 1 that captures an image of a dot pattern.

[Electronic pen]
Next, the electronic pen 1 will be described. As shown in FIG. 4, the electronic pen 1 includes a pen unit 104, an LED 105, a CMOS camera 106, a pressure sensor 107, a processor 108 including a CPU, a memory 109 such as a ROM and a RAM, A communication unit 111 including a real-time clock 110, an antenna, and the like, and a battery 112 are provided. The tip of the pen unit 104 is a pen point unit 103, and the user touches the pen point unit 103 of the electronic pen 1 against the paper 3 or the transparent film 4 and enters a stroke (handwritten stroke) of characters or the like. Or tapping (tapping the paper 3 or the transparent film 4 with the pen tip 103). Here, the first contact of the pen tip portion 103 of the electronic pen 1 with the paper 3 and the transparent film 4 is referred to as pen down, and the pen tip portion 103 is separated from the contact (contact) state. Called up. A trajectory written between the pen-down and pen-up of the electronic pen 1 is one stroke, and characters, figures, etc. are composed of one or a plurality of strokes. Note that the pen unit 104 may be configured as an ink cartridge so that ink comes out from the pen tip unit 103.

  The battery 112 is for supplying electric power to each component in the electronic pen 1. For example, the battery 112 is configured to turn on / off the electronic pen 1 itself by attaching and detaching a cap (not shown) of the electronic pen 1. May be. The real time clock 110 transmits time information indicating the current time (time stamp) and supplies the time information to the processor 108. The pressure sensor 107 detects the pressure applied from the pen tip portion 103 through the pen portion 104 when the user writes or taps characters or marks on the paper 3 or the transparent film 4 with the electronic pen 1, that is, the writing pressure. The value is transmitted to the processor 108.

  The processor 108 switches on / off the switches of the LED 105 and the CMOS camera 106 based on the writing pressure data supplied from the pressure sensor 107. That is, when the user writes characters on the paper 3 or the transparent film 4 with the electronic pen 1, the pen pressure is applied to the pen tip portion 103, and when the pressure sensor 107 detects a writing pressure higher than a predetermined value, the processor 108. Determines that the user has started entry, and activates the LED 105 and the CMOS camera 106. Then, the communication unit 111 associates pen down information PD detected by the pressure sensor 107 with a pen ID described later, and transmits it as entry information to the external device terminal 2. Further, when the user finishes entering one stroke and moves the electronic pen 1 away from the paper 3 or the transparent film 4, the pressure sensor 107 detects pen-up because no writing pressure exceeding a predetermined value is detected. Then, the communication unit 111 associates the pen-up information PU detected by the pressure sensor 107 with the pen ID, and transmits it to the external device terminal 2 as entry information.

The LED 105 and the CMOS camera 106 are attached near the pen tip portion 103 of the electronic pen 1, and an opening 102 is formed in a portion of the housing 101 that faces the LED 105 and the CMOS camera 106. The LED 105 illuminates infrared rays toward the vicinity of the pen tip portion 103 on the paper 3 or the transparent film 4. The region is slightly shifted from the position where the pen tip portion 103 contacts the paper 3 or the transparent film 4. The CMOS camera 106 images the area illuminated by the LED 105 and supplies image data obtained by the imaging to the processor 108. Note that the shooting area by the CMOS camera 106 is a range including a size of about 2 mm × about 2 mm as shown in FIG. 3A, and the shooting by the CMOS camera 106 is performed at regular intervals of about 50 to 100 times per second. Is called. Further, an infrared transmission filter may be provided in front of the CMOS camera 106 on the opening 102 side.
The LED 105 corresponds to an example of “infrared irradiation means” in the present invention, and the CMOS camera 106 corresponds to an example of “imaging means” in the present invention.

The processor 108 recognizes the dot pattern by processing the image data supplied from the CMOS camera 106 during the user's entry, and X on the paper 3 or the transparent film 4 of the stroke (handwriting) to be entered by the user. , Y coordinates (also simply referred to as “position coordinates” or “coordinate data”) are continuously calculated. That is, the processor 108 converts the image data of the dot pattern as shown in FIG. 3A supplied by the CMOS camera 106 into the data array shown in FIG. The data is converted into a Y coordinate bit value, and X, Y coordinate data is calculated from the data array by a predetermined calculation method. The processor 108 associates the current time (time stamp: entered time information) transmitted from the real-time clock 110, the pen pressure data, and the X and Y coordinate data. Note that the 6 × 6 dot pattern on the paper 3 or the transparent film 4 does not overlap in the paper 3 or the transparent film 4, so when the user enters characters or the like with the electronic pen 1, the written position is changed. The position on the sheet 3 or the transparent film 4 can be specified by coordinate calculation by the processor 108.
The processor 108 corresponds to an example of “binarization processing means”, “region comparison means”, “negative / positive inversion processing means”, and “encoding pattern recognition means” in the present invention.

  The memory 109 stores property information such as a pen ID such as “pen01” for identifying the electronic pen 1, a pen manufacturer number, and a pen software version. Then, the communication unit 111 associates the pen ID (electronic pen identification information), time information (time stamp), writing pressure data, and X and Y coordinate data, and transmits them to the external device terminal 2 as entry information. . Transmission to the external device terminal 2 by the communication unit 111 is immediately and sequentially performed by wireless transmission such as Bluetooth (registered trademark).

  Next, the entry information transmitted from the electronic pen 1 will be described with reference to FIG. When the user enters a stroke or the like on the paper 3 or the transparent film 4 using the electronic pen 1, first, the electronic pen 1 is brought into contact with the paper 3 or the transparent film 4. Then, the pressure sensor 107 of the electronic pen 1 detects the writing pressure applied to the pen tip portion 103. When the processor 108 of the electronic pen 1 determines that the pressure sensor 107 has detected a writing pressure of a predetermined value or more, the pen down information PD indicating the contact of the electronic pen 1 with the paper 3 or the transparent film 4 and the identification of the electronic pen 1 Entry information that associates information such as a pen ID is generated, and the communication unit 111 transmits the entry information to the external device terminal 2. After the user touches the paper 3 or the transparent film 4 of the pen tip portion 103 of the electronic pen 1, the user moves the pen tip portion 103 to draw a stroke. The processor 108 also continues to obtain coordinate information (X, Y), coordinate attribute information including pen pressure data (P) detected by the pressure sensor 107, time information (T) transmitted by the real-time clock 110, and entry information in association with the pen ID, the CMOS camera 106 Are sequentially generated in accordance with the dot pattern imaging cycle of, and the communication unit 111 sequentially transmits the entry information to the external device terminal 2. When the user finishes drawing the stroke and moves the electronic pen 1 away from the paper 3 or the transparent film 4, the pressure sensor 107 does not detect the writing pressure. Therefore, the processor 108 detects the writing pressure of a predetermined value or more by the pressure sensor 107. It is determined that the electronic pen 1 has disappeared, and the pen-up information PU indicating the separation of the electronic pen 1 into the paper 3 or the transparent film 4 is generated and communication information is generated by associating the pen ID that is the identification information of the electronic pen 1 with communication information. The unit 111 is made to transmit the entry information to the external device terminal 2. In addition, the dot pattern address obtained from the coordinate information may be included in the entry information transmitted from the electronic pen 1 to the external device terminal 2 in this way.

[External device terminal]
Next, the external device terminal 2 will be described. The external device terminal 2 includes, as hardware, an antenna device capable of data communication with the electronic pen 1, a processor such as a CPU, a memory such as ROM and RAM, a display, a personal computer including a mouse and a keyboard, and the like. The FIG. 6 is a functional block diagram of the external device terminal 2. Functionally, the external device terminal 2 includes an input unit 21 such as a mouse and a keyboard, a reception unit 22, a transmission unit 23, a display unit 24, a storage unit 25, and a processing unit 26. Then, the external device terminal 2 performs a predetermined process based on the entry information received from the electronic pen 1.

  The receiving means 22 is constituted by an antenna receiving circuit or the like, receives entry information from the electronic pen 1 and transmits it to the processing means 26. The transmission unit 23 transmits a video signal according to an instruction from the processing unit 26 to a projector (not shown). The display means 24 is constituted by a display or the like, and displays the contents instructed by the processing means 26. The storage unit 25 is configured by a memory such as a ROM or a RAM. For example, the storage unit 25 stores the entry information received from the electronic pen 1 for each pen ID according to the processing instruction of the processing unit 26.

  The processing means 26 is constituted by a processor such as a CPU, and executes predetermined processing. Specifically, the processing unit 26 causes the display unit 24 to display a stroke based on the entry information received by the receiving unit 22. Further, when a projector is connected to the transmission unit 23, the processing unit 26 sends a video signal for causing the projector to project an image similar to the image to be displayed on the display unit 24. To send to.

[Dot pattern recognition method]
Next, a method for recognizing a dot pattern (an example of “encoding pattern”) using the electronic pen 1 in the present embodiment will be specifically described.

  As described above, the LED 105 of the electronic pen 1 illuminates infrared light toward the vicinity of the pen tip portion 103 on the paper 3 or the transparent film 4, and the CMOS camera 106 of the electronic pen 1 images the area illuminated by the LED 105. To do. Here, when the infrared rays are illuminated on the paper 3, the dots in the paper 3 are printed with the infrared absorbing ink. Therefore, the dot portion absorbs the infrared rays so that the amount of reflected infrared rays is small. The portions other than the dots have a large amount of infrared reflection. On the other hand, when the transparent film 4 is illuminated with infrared rays, the dots in the transparent film 4 are printed with infrared reflection ink, and the dot portion reflects infrared rays, so the amount of infrared reflection is large. On the other hand, the amount of reflected infrared light is small in portions other than dots. For this reason, the captured image of the paper 3 and the captured image of the transparent film 4 are different. Basically, the contrast between the captured image of the paper 3 and the captured image of the transparent film 4 is opposite for the dot portion and the portion other than the dot.

  Subsequently, the processor 108 of the electronic pen 1 receives the captured image as described above from the CMOS camera 106 and recognizes the dot pattern by performing processing on the captured image. Specifically, first, the processor 108 performs binarization processing on the supplied captured image using a predetermined threshold (hereinafter, the binarized image is appropriately referred to as “binarized image”). Call it.) A preset constant (fixed value) or a variable may be used as the threshold used when performing the binarization process. When a variable is used for the threshold, for example, a value changed according to the captured image can be used.

  FIG. 7 shows an example of a binarized image. Specifically, FIG. 7A shows an example of an image obtained by binarizing the captured image of the paper 3, and FIG. 7B shows an example of an image obtained by binarizing the captured image of the transparent film 4. Show. As shown in FIG. 7A, in the binarized image on the paper 3, the dot portion has a small amount of infrared reflection and thus a black image, and the portion other than the dot has a large amount of infrared reflection and thus has a white color. It becomes an image. On the other hand, as shown in FIG. 7B, in the binarized image of the transparent film 4, the dot portion has a large amount of infrared reflection, and thus becomes a white image, and the portion other than the dot reflects infrared. Since the amount is small, a black image is obtained. Thus, in the binarized image on the paper 3 and the binarized image on the transparent film 4, the black and white are reversed for the dot portion and the portion other than the dot.

  In the following, a black part region in the binarized image, in other words, a region having a small amount of infrared reflection (in other words, a region having a large amount of infrared absorption) is referred to as an “infrared absorption region”. On the other hand, a white area in the binarized image, in other words, an area having a large amount of infrared reflection is called an “infrared reflection area”.

  Subsequently, the processor 108 discriminates the infrared reflection area and the infrared absorption area from the binarized image obtained by the above binarization processing, and compares the magnitude relationship between the area of the infrared reflection area and the area of the infrared absorption area. To do. Specifically, the processor 108 determines whether or not the area of the infrared absorption region is larger than the area of the infrared reflection region.

  Since the total area of dots in the imaging range is smaller than the area other than the dots, the processor 108 determines that the area of the infrared absorption region is larger than the area of the infrared reflection region in the binarized image, in other words, in the binarized image. When the area of the black portion is larger than the area of the white portion, negative / positive inversion processing is performed on the binarized image (hereinafter, the image subjected to the negative / positive inversion processing is appropriately referred to as “negative / positive inversion image”). . That is, the processor 108 converts a black infrared absorption region into white, and converts a white infrared reflection region into black. As a result, a binarized image in which the dot portion is white and the portion other than the dot is black as shown in FIG. 7B, and the dot portion is black as shown in FIG. 7A. The portion other than the dot is converted into an image in which the portion is white. The processor 108 recognizes the dot pattern based on the negative / positive inversion image when the negative / positive inversion processing is performed as described above.

  On the other hand, when the area of the infrared absorption region is equal to or smaller than the area of the infrared reflection region in the binarized image, the processor 108, in other words, the area of the black portion in the binarized image is equal to or smaller than the area of the white portion. The negative / positive inversion process is not performed on the binarized image. In this case, the processor 108 recognizes the dot pattern based on the original binarized image. That is, the processor 108 recognizes the dot pattern based on an image in which the dot portion is black and the portion other than the dot is white as shown in FIG.

  According to the dot pattern recognition method described above, an image used when recognizing a dot pattern can be unified into an image in which a dot portion is black and a portion other than dots is white. This makes it possible to appropriately recognize both the dot pattern printed with the infrared absorbing ink and the dot pattern printed with the infrared reflective ink.

  Note that the present invention is not limited to discriminating the infrared reflection region and the infrared absorption region for the entire region of the binarized image obtained by binarizing the captured image, and comparing the size relationship between the regions. An infrared reflection region and an infrared absorption region may be determined for a predetermined region of a part of the binarized image (for example, a region having a predetermined size located at a preset location), and the size relationship between the regions may be compared. . In such a case, it is possible to speed up the processing.

[Entry information transmission process flow]
The entry information transmission processing flow by the electronic pen 1 of this embodiment will be described with reference to FIG. The entry information transmission process flow is performed for the electronic pen 1 to send entry information to the external device terminal 2.

  First, in step S <b> 101, the processor 108 of the electronic pen 1 determines whether pen-down is detected by the pressure sensor 107. Specifically, the processor 108 determines whether or not the pressure sensor 107 detects a writing pressure equal to or higher than a predetermined value. If pen-down is detected (step S101; Yes), the process proceeds to step S102. In this case, the processor 108 causes the communication unit 111 to transmit the pen ID and the pen-down information to the external device terminal 2 (step S102). Then, the process proceeds to step S103. On the other hand, when pen-down is not detected (step S101; No), the process ends.

  In step S103, the processor 108 analyzes the dot pattern printed on the paper 3 or the transparent film 4, and transmits the information obtained from the analyzed coding pattern to the external device terminal 2 by the communication unit 111 (coding pattern analysis). Transmission process). Details of the encoding pattern analysis transmission process will be described later. Then, the process proceeds to step S104. In step S <b> 104, the processor 108 determines whether pen up is detected by the pressure sensor 107. Specifically, the processor 108 determines whether or not the pressure sensor 107 no longer detects a writing pressure of a predetermined value or more. When pen-up is detected (step S104; Yes), the process proceeds to step S105. In this case, the processor 108 causes the communication unit 111 to transmit the pen ID and the pen-up information to the external device terminal 2 (step S105). Then, the process ends. On the other hand, when pen-up is not detected (step S104; No), the process returns to step S103.

[Encoding pattern analysis transmission processing flow]
A coding pattern analysis transmission processing flow by the electronic pen 1 of the present embodiment will be described with reference to FIG. The coding pattern analysis transmission process flow is performed in step S103 of the entry information transmission process flow shown in FIG.

  First, in step S <b> 201, the processor 108 of the electronic pen 1 illuminates infrared rays from the LED 105 toward the vicinity of the pen tip portion 103 on the paper 3 or the transparent film 4. Then, the process proceeds to step S202. In step S <b> 202, the processor 108 causes the CMOS camera 106 to image the area illuminated by the LED 105. In addition, the processor 108 acquires a captured image captured by the LED 105. Then, the process proceeds to step S203.

  In step S203, the processor 108 performs a binarization process using a predetermined threshold on the captured image acquired in step S202. For example, when the pixel value (density value / luminance value) in the captured image is larger than the threshold value, the processor 108 sets the pixel to white, and the pixel value (density value / luminance value) in the captured image is the threshold value. In the following cases, the pixel is set to black. Then, the process proceeds to step S204. In step S204, the processor 108 discriminates the infrared reflection area and the infrared absorption area from the binarized image generated in step S203, and determines whether the area of the infrared absorption area is larger than the area of the infrared reflection area. . For example, the processor 108 performs the determination by using the total number of black pixels in the binarized image as the area of the infrared absorption region and using the total number of white pixels in the binarized image as the area of the infrared reflection region. .

  When the area of the infrared absorption region is larger than the area of the infrared reflection region (step S204; Yes), the process proceeds to step S205. In step S205, the processor 108 performs negative / positive inversion processing on the binarized image generated in step S203. That is, a process of inverting black and white of the binarized image is performed. Then, the process proceeds to step S206. On the other hand, when the area of the infrared absorption region is equal to or smaller than the area of the infrared reflection region (step S204; No), the process proceeds to step S206. In this case, the processor 108 does not perform negative / positive inversion processing.

  In step S206, the processor 108 determines whether or not a dot pattern can be recognized from the image. Specifically, the processor 108 performs the determination based on the negative / positive reversal image when the negative / positive reversal process is performed, and on the other hand, when the negative / positive reversal process is not performed, the original binary value is obtained. The determination is performed based on the digitized image. For example, the processor 108 determines whether or not it can be recognized as a dot pattern depending on whether or not there are dots (code symbols) with a certain range of diameters. If the dot pattern is recognizable (step S206; Yes), the process proceeds to step S207. If the dot pattern is not recognizable (step S206; No), the process ends.

  In step S207, the processor 108 calculates a coordinate value by a predetermined calculation method based on the dot pattern recognized in step S206. Then, the process proceeds to step S208. In step S208, the processor 108 associates the coordinate value calculated in step S207 with the pen ID and causes the communication unit 111 to transmit the coordinate value to the nearby external device terminal 2. Then, the process ends.

[Effects of electronic pen of this embodiment]
According to the electronic pen 1 described above, the dot pattern printed by the infrared absorbing ink is obtained by comparing the infrared reflecting area and the infrared absorbing area and performing a negative / positive reversal process on the binarized image according to the comparison result. For both the dot pattern printed with the infrared reflective ink and the dot pattern, an image in which the dot portion and the portion other than the dot are represented in the same manner can be used for the dot pattern recognition. Therefore, it is possible to appropriately recognize both the dot pattern printed with the infrared absorbing ink and the dot pattern printed with the infrared reflective ink. Specifically, it is possible to appropriately recognize both the dot pattern printed on the paper 3 and the dot pattern printed on the transparent film 4.

[Modification]
In the above, an embodiment has been described in which negative-positive inversion processing is performed on a binarized image in which the area of the infrared absorption region is larger than the area of the infrared reflection region. Instead, the area of the infrared absorption region is that of the infrared reflection region. Negative / positive inversion processing may be performed on a binarized image having an area equal to or smaller than the area. That is, in another example, when the area of the infrared absorption region is equal to or less than the area of the infrared reflection region in the binarized image, negative / positive inversion processing is performed on the binarized image. When the area of the infrared absorption region in the digitized image is larger than the area of the infrared reflection region, the negative / positive inversion process can not be performed on the binarized image. In this example, a binarized image in which the dot portion is black and the portion other than the dot is white as shown in FIG. 7A, and the dot portion is white as shown in FIG. 7B. Thus, the image is converted into an image in which portions other than the dots are black. Thereby, the image used when recognizing the dot pattern can be unified into an image in which the dot portion is white and the portion other than the dot is black. Therefore, even in this example, it is possible to appropriately recognize both the dot pattern printed with the infrared absorbing ink and the dot pattern printed with the infrared reflective ink.

In the above description, the embodiment has been described in which the electronic pen 1 performs all the processes for recognizing the dot pattern. However, the present invention is not limited to this. In another example, the electronic pen 1 performs only the process of irradiating the paper 3 or the transparent film 4 with infrared rays and imaging the infrared irradiation area, and the external device terminal 2 is a method similar to the method described above. Thus, a process of recognizing a dot pattern based on the captured image can be performed. Specifically, the external device terminal 2 receives the captured image from the electronic pen 1, performs binarization processing on the captured image, determines the infrared reflection region and the infrared absorption region, and determines the area of the infrared reflection region. The magnitude relationship with the area of the infrared absorption region is compared. Then, the external device terminal 2 performs a negative / positive inversion process on the binarized image according to the comparison result, and recognizes a dot pattern based on the negative / positive inversion image or the binarized image. Such processing is executed by the processing means 26 in the external device terminal 2.
In this example, the external device terminal 2 corresponds to an example of a “terminal device” in the present invention. The processing means 26 in the external device terminal 2 corresponds to an example of “binarization processing means”, “region comparison means”, “negative / positive inversion processing means”, and “encoding pattern recognition means” in the present invention. .

  In the above, an embodiment using an encoding pattern represented by a dot pattern has been described. However, other than this, a pattern from which coordinate data can be derived by a code symbol such as a circle, a square, or a triangle is encoded pattern. It may be used as Also, the coding pattern may include code symbols having different sizes, shapes, colors, and the like.

DESCRIPTION OF SYMBOLS 1 ... Electronic pen 10 ... Information processing system 104 ... Pen part 105 ... LED
DESCRIPTION OF SYMBOLS 106 ... CMOS camera 107 ... Pressure sensor 108 ... Processor 111 ... Communication unit 2 ... External device terminal 26 ... Processing means 3 ... Paper 4 ... Transparent film

Claims (6)

Infrared irradiation means for irradiating the sheet on which the coding pattern is formed with infrared rays;
Imaging means for imaging an area irradiated with infrared rays by the infrared irradiation means;
Binarization processing means for performing binarization processing on a captured image captured by the imaging means using a predetermined threshold;
An area comparison unit that determines an infrared reflection area and an infrared absorption area from the binarized image, and compares a size relationship between the area of the infrared reflection area and the area of the infrared absorption area;
Negative / positive inversion processing means for performing negative / positive inversion processing on the binarized image according to the comparison result by the area comparison means;
When the negative / positive inversion processing unit performs the negative / positive inversion processing, the coding pattern is recognized based on the negative / positive inversion processing image, and the negative / positive inversion processing unit does not perform the negative / positive inversion processing. And a coding pattern recognition means for recognizing the coding pattern based on the binarized image.   The region comparison unit determines the infrared reflection region and the infrared absorption region from a predetermined region of a part of the binarized image, and the magnitude relationship between the area of the infrared reflection region and the area of the infrared absorption region The electronic pen according to claim 1, wherein the electronic pens are compared.   3. The sheet according to claim 1, wherein the sheet includes a sheet on which the coding pattern is printed with an infrared absorbing ink, and a sheet on which the coding pattern is printed with an infrared reflective ink. The electronic pen described. An information processing system comprising an electronic pen and a terminal device,
The electronic pen is
Infrared irradiation means for irradiating the sheet on which the coding pattern is formed with infrared rays;
Imaging means for imaging an area irradiated with infrared rays by the infrared irradiation means;
Transmission means for transmitting the captured image captured by the imaging means to the terminal device,
The terminal device
Receiving means for receiving the captured image transmitted from the transmitting means of the electronic pen;
Binarization processing means for performing binarization processing using a predetermined threshold on the captured image received by the reception means;
An area comparison unit that determines an infrared reflection area and an infrared absorption area from the binarized image, and compares a size relationship between the area of the infrared reflection area and the area of the infrared absorption area;
Negative / positive inversion processing means for performing negative / positive inversion processing on the binarized image according to the comparison result by the area comparison means;
When the negative / positive inversion processing unit performs the negative / positive inversion processing, the coding pattern is recognized based on the negative / positive inversion processing image, and the negative / positive inversion processing unit does not perform the negative / positive inversion processing. And a coding pattern recognition means for recognizing the coding pattern based on the binarized image.   The region comparison unit determines the infrared reflection region and the infrared absorption region from a predetermined region of a part of the binarized image, and the magnitude relationship between the area of the infrared reflection region and the area of the infrared absorption region The information processing system according to claim 4, wherein the information processing systems are compared.   6. The sheet according to claim 4, wherein the sheet includes a sheet on which the coding pattern is printed with an infrared absorbing ink, and a sheet on which the coding pattern is printed with an infrared reflective ink. The information processing system described.

Images