JP4464622B2 - Reader and electronic blackboard using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reading apparatus for reading a color original by an RGB light source switching method and an electronic blackboard using the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a color reading apparatus that performs line sequential reading on a color original using three light sources and a charge coupled device is known.
[0003]
In such a color reading apparatus, for example, in order to eliminate a difference in reading position in one horizontal line that occurs due to a time difference for reading each RGB by a line sequential scanning method, A technique is disclosed in which the driving of the moving means is stopped when receiving the light, while the moving means is driven when receiving the RGB light from the document (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-7-143286
[0005]
[Problems to be solved by the invention]
However, according to the conventional technique, since the original and the RGB light source are relatively intermittently driven in order to eliminate the difference in the reading position, the control of the drive system becomes complicated and the reading speed is reduced. There was a problem.
[0006]
If it is a single line sensor, there is a possibility that the control of the drive system can be permitted even with the above-described conventional configuration, but for example, a large-scale arrangement in which n line sensors such as an electronic blackboard are arranged in a row. In this sensor unit, it is desired to increase the reading speed, and measures other than the drive system are required.
[0007]
The present invention has been made in view of such a problem, and a reading apparatus capable of increasing the reading speed and eliminating the inconvenience due to the difference in the reading position of each light of RGB is used. The purpose is to provide an electronic blackboard.
[0008]
[Means for Solving the Problems]
The present invention An RGB light source that emits R, G, and B light toward the reading surface; a line sensor that receives reflected light from the reading surface and reads an image in pixel units; and the RGB light source along the reading surface; Moving means for moving the reading target on the reading surface at a substantially constant speed so as to pass the line sensor or the reading position of the line sensor, and lighting of the RGB light source during the reading period of one line of the line sensor Light source control means for generating four types of irradiation light of the three colors of monochromatic light of R, G, and B and the combined light that is lit and divided by 1/3 of the lighting time of the three colors of monochromatic light When the reading surface is read in color, the sum of the values corresponding to the pixel data of each color read according to the monochromatic light approximates the triple value corresponding to the pixel data read according to the combined light. If it is a value Outputs pixel data of each color using pixel data of each color read according to the monochromatic light as effective pixels, while a sum of values corresponding to the pixel data of each color read according to the monochromatic light is added to the combined light. If the pixel data read in response to the monochromatic light is not a value approximate to a value corresponding to three times the pixel data read in response, the pixel data of each color previously output as the effective pixel as the invalid pixel. And image processing means for outputting after replacing Is.
[0009]
According to the present invention, the line sensor or the like is moved at a substantially constant speed. While reading the image, invalid pixels become effective pixels Since the replacement can be performed, the reading speed can be increased, and the inconvenience due to the difference in the reading position of the R, G, and B light in the RGB light source can be eliminated.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A reading apparatus according to a first aspect of the present invention receives an RGB light source that irradiates light of R, G, and B toward a reading surface, and reflected light from the reading surface. Images in pixel units A line sensor for reading, and a moving means for moving the reading target on the reading surface at a substantially constant speed so as to pass the RGB light source and the line sensor along the reading surface, or the reading position of the line sensor; The RGB light source is turned on sequentially during the reading period of one line of the line sensor, and the combined lighting is performed by dividing each of R, G, and B single-color light and 1/3 of the lighting time of the three-color single-color light. Light source control means for generating four types of irradiation light and light, and reading the reading surface in color When the sum of the values corresponding to the pixel data of each color read according to the monochromatic light is a value approximate to a triple value of the value corresponding to the pixel data read according to the combined light, the monochromatic color While outputting the pixel data of each color using the pixel data of each color read according to light as the effective pixel, the sum of the values corresponding to the pixel data of each color read according to the monochromatic light was read according to the combined light If it is not a value that approximates the triple value corresponding to the pixel data, the pixel data of each color read in accordance with the monochromatic light is replaced with the pixel data of each color that was previously output as an effective pixel as an invalid pixel. Image processing means for outputting; The structure which comprises is taken.
[0013]
This configuration According to the above, while moving the line sensor etc. at a substantially constant speed While reading the image, invalid pixels become effective pixels Since the replacement can be performed, the reading speed can be increased, and the inconvenience due to the difference in the reading position of the R, G, and B light in the RGB light source can be eliminated.
[0016]
In particular, According to this configuration, each color read in accordance with monochromatic light. Pixel The sum of the values corresponding to was read according to the combined light Pixel Effective depending on whether the value approximates to 3 times the value corresponding to Pixel Or invalid Pixel It is easy to determine Pixel Is invalid Pixel Can be determined.
[0017]
Also, each color read according to monochromatic light Pixel The sum of the values corresponding to is read according to the combined light Pixel Effective depending on whether the value approximates to 3 times the value corresponding to Pixel Or invalid Pixel Therefore, it is possible to give a certain range of color misalignment comparison when reading a color image, and it is invalid more than necessary. Pixel Detected and invalid Pixel Enable Pixel It is possible to prevent the occurrence of the process of replacing with.
[0019]
further, According to this configuration, disabled Pixel Is detected, it is invalid Pixel Valid detected before detecting Pixel Ineffective Pixel So that the invalid Pixel Valid detected before detecting Pixel While referring to Pixel Thus, the color misregistration generated in the read image can be corrected without a sense of incongruity.
[0020]
Of the present invention Second The aspect is First In the reading apparatus according to the aspect, When the pixel data read first is an invalid pixel, the image processing means replaces the pixel data with white pixel data and outputs the result. Take the configuration.
[0021]
According to this configuration, first Read pixel Invalid Pixelated If White pixel data Is replaced with Pixel Valid detected before detecting Pixel Even when it is configured to replace Read pixel It is possible to cope with color misregistration occurring in
[0028]
An electronic blackboard equipped with a self-propelled color sensor unit, receiving an RGB light source that irradiates light of R, G, and B toward a reading surface, and reflected light from the reading surface Images in pixel units A line sensor for reading, and a moving means for moving the reading target on the reading surface at a substantially constant speed so as to pass the RGB light source and the line sensor along the reading surface, or the reading position of the line sensor; The RGB light source is turned on sequentially during the reading period of one line of the line sensor, and the combined lighting is performed by dividing each of R, G, and B single-color light and 1/3 of the lighting time of the three-color single-color light. Light source control means for generating four types of irradiation light and light, and reading the reading surface in color When the sum of the values corresponding to the pixel data of each color read according to the monochromatic light is a value approximate to a triple value of the value corresponding to the pixel data read according to the combined light, the monochromatic color While outputting the pixel data of each color using the pixel data of each color read according to light as the effective pixel, the sum of the values corresponding to the pixel data of each color read according to the monochromatic light was read according to the combined light If it is not a value approximate to the triple value corresponding to the pixel data, the pixel data of each color read in accordance with the monochromatic light is replaced with the pixel data of each color output as the valid pixel last time as an invalid pixel. Image processing means for outputting; The structure which comprises is taken.
[0031]
This configuration According to the above, while moving the line sensor etc. at a substantially constant speed While reading the image, invalid pixels become effective pixels Since the replacement can be performed, the reading speed can be increased, and the inconvenience due to the difference in the reading position of the R, G, and B light in the RGB light source can be eliminated.
[0034]
In particular, According to this configuration, each color read in accordance with monochromatic light. Pixel The sum of the values corresponding to was read according to the combined light Pixel Effective depending on whether the value approximates to 3 times the value corresponding to Pixel Or invalid Pixel It is easy to determine Pixel Is invalid Pixel Can be determined.
[0035]
Also, each color read according to monochromatic light Pixel The sum of the values corresponding to is read according to the combined light Pixel Effective depending on whether the value approximates to 3 times the value corresponding to Pixel Or invalid Pixel Therefore, it is possible to give a certain range of color misalignment comparison when reading a color image, and it is invalid more than necessary. Pixel Detected and invalid Pixel Enable Pixel It is possible to prevent the occurrence of the process of replacing with.
[0037]
further, According to this configuration, disabled Pixel Is detected, it is invalid Pixel Valid detected before detecting Pixel Ineffective Pixel So that the invalid Pixel Valid detected before detecting Pixel While referring to Pixel Thus, the color misregistration generated in the read image can be corrected without a sense of incongruity.
[0038]
Of the present invention 4th The aspect is Third In the electronic blackboard according to the aspect, When the pixel data read first is an invalid pixel, the image processing means replaces the pixel data with white pixel data and outputs the result. Take the configuration.
[0039]
According to this configuration, first Read pixel Invalid Pixelated If White pixel data Is replaced with Pixel Valid detected before detecting Pixel Even when it is configured to replace Read pixel It is possible to cope with color misregistration occurring in
[0046]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0047]
FIG. 1 is a perspective view showing an external configuration of a color electronic blackboard equipped with a reading device according to an embodiment of the present invention.
[0048]
As shown in FIG. 1, a color electronic blackboard 100 according to the present embodiment includes a white board surface 101 on which information such as characters is written by a user. A reading unit 102 as a reading apparatus according to the present invention is provided on the front surface of the board surface 101. The reading unit 102 includes a reading motor 103 as a moving unit that moves above the board surface 101. The reading motor 103 moves in the horizontal direction on a rail 104 formed above the board surface 101. By driving the reading motor 103, the reading unit 102 moves the front surface of the board surface 101 in the horizontal direction.
[0049]
Although FIG. 1 shows the case where the board surface 101 moves from the right side to the left side as the moving direction, the present invention is not limited to this, and a configuration in which the board surface 101 moves in the reverse direction is also possible. In addition, although the configuration in which the reading unit 102 is moved is described in FIG. 1, the reading position of the reading unit 102 may be moved on a board surface 101 that is fixed and rotated.
[0050]
The reading unit 102 incorporates a line sensor 105 on the surface facing the board surface 101. As will be described later, the line sensor 105 is configured by connecting a plurality of (n) line sensors, and is provided with a length corresponding to the information writing area on the board surface 101 in a state where all the line sensors are connected. It has been. In the following, information to be read written on the board surface 101 is referred to as a document. The line sensor 105 reads a document written on the board surface 101 while the reading unit 102 is moving.
[0051]
Below the board surface 101 is provided a tray 106 on which a marker for writing a document on the board surface 101 and a cleaner for erasing the document are placed. Below the left end of the tray 106 is provided a control box 107 containing an overall control unit for controlling the entire color blackboard 100. On the upper surface of the control box 107, an operation panel 108 for receiving user instructions is provided. For example, an instruction to read a document is input from the operation panel 108 by the user.
[0052]
FIG. 2 is a block diagram showing a configuration of the color electronic blackboard 100 according to the present embodiment.
[0053]
As shown in the figure, a color electronic blackboard 100 according to the present embodiment includes the above-described reading unit 102, an overall control unit 201, a user interface unit (hereinafter referred to as “user I / F unit”) 202, The printer unit 203 and a personal computer interface (hereinafter referred to as “PCI / F”) 204.
[0054]
Of these configurations, the overall control unit 201, the user I / F unit 202, the printer unit 203, and the PCI / F 204 are accommodated in the control box 107 described above. In particular, the user I / F unit 202 operates with the operation panel 108 described above and accepts user instructions.
[0055]
The reading unit 102 includes light sources 205 of three colors of R (Red), G (Green), and B (Blue). Hereinafter, when the light source of each color is shown, it is shown as an R light source 205R, a G light source 205G, and a B light source 205B. Each color light source 205 lights each color light (monochromatic light) to the board surface 101. The lighting timing of each color light source 205 is controlled by a light source control circuit 206 as a light source control means. Under the control of the light source control circuit 206, the light source 205 turns on not only monochromatic light but also white light (synthesized light) obtained by synthesizing light of all colors. Specifically, the light source control circuit 206 turns on white (W) white combined light and then turns on R, G, and B monochromatic light. The generation of synthesized light will be described later.
[0056]
The line sensor 105 receives the reflected light from the board surface 101 by the combined light or the monochromatic light from the light source 205 and reads the image signal. The line sensor 105 of this embodiment is configured by connecting four line sensors corresponding to A4 paper. Hereinafter, when each line sensor is shown, it is shown as a line sensor 105A, a line sensor 105B, a line sensor 105C, and a line sensor 105D from above shown in FIG. Note that the reading unit 102 of the present invention is also applicable to a line sensor configured by connecting a number of line sensors other than four. The image signal read by the line sensor 105 is output to the selector 207. The output timing of the image signal to the selector 207 in each line sensor 105A-D is controlled by the line sensor control circuit 208.
[0057]
The selector 207 selects image signals input from the four line sensors. That is, the image signal input from any of the line sensors 105A to 105D is selected. Then, the selected image signal is output to the A / D conversion circuit 209. Note that the selector 207 performs thinning processing of the image signal input from the line sensor 105. As a result, the color electronic blackboard 100 that reads a large amount of image signals using four line sensors can perform processing without requiring a large-capacity line memory.
[0058]
The A / D conversion circuit 209 converts the image signal input as analog data into a digital signal. The image signal after digital conversion is output to the line memory 210.
[0059]
The line memory 210 stores image signals for one line in the main scanning direction of the line sensor 105. In the line sensor 105 of this embodiment, the vertical direction of the board surface 101 is the main scanning direction, and the horizontal direction is the sub-scanning direction.
[0060]
The image processing circuit 211 functions as an image signal conversion unit, acquires pixel data constituting an image signal stored in the line memory 210, and performs image processing such as comparison processing and replacement processing on the pixel data. By this image processing, the color shift generated in the pixel data is corrected. Pixel data that has undergone image processing is output to the overall control unit 201. Note that image processing for color misregistration correction in the image processing circuit 211 will be described later.
[0061]
The reading unit 102 includes the reading motor 103 as described above. The driving timing and driving time of the reading motor 103 are controlled by the reading motor driving circuit 212. The light source control circuit 206 and the line sensor control circuit 208, including the reading motor drive circuit 212, start processing in response to an instruction from the CPU of the overall control unit 201.
[0062]
The overall control unit 201 includes a CPU 213 that controls the overall components of the color electronic blackboard 100 including the reading unit 102, and a memory 214 that stores a control program for the CPU 213 and supplies a work area for the CPU 213. Yes. An area for accumulating image signals (pixel data) input from the reading unit 102 is also allocated to the memory 214.
[0063]
The user interface unit 202, printer unit 203, and PCI / F 204 described above are connected to the CPU 213. Under the control of the CPU 213, the user I / F unit 202 receives a user instruction via the operation panel 108 and displays a message indicating the current state of the color electronic blackboard 100 on the operation panel 108.
[0064]
The printer unit 203 prints a document written on the board surface 101 under the control of the CPU 213. The PCI / F 204 is an interface between the color electronic blackboard 100 and a personal computer (hereinafter referred to as “PC”), and the CPU 213 reads a document written on the board surface 101 via the PCI / F 204 as a PC. Display on the display connected to.
[0065]
FIG. 3 is a block diagram showing a configuration of the image processing circuit 211 of the reading unit 102 according to the present embodiment.
[0066]
As described above, the line memory 210 stores the image signal for one line passed from the A / D conversion circuit 209. As shown in FIG. 3, the line memory 210 is divided into line memories corresponding to the respective colors (W, R, G, and B). Hereinafter, the line memories for the respective colors are referred to as a W line memory 210W, an R line memory 210R, a G line memory 210G, and a B line memory 210B.
[0067]
In each of the line memories 210W to 210B, pixel data of the first pixel to the nth pixel are accumulated. In FIG. 3, the pixel data of the first pixel of white (W) is indicated as “W1”, and the pixel data of the nth pixel of white (W) is indicated as “Wn”. When the pixel data of the first pixel to the n-th pixel of the line memories 210W to 210B for each color is accumulated, the image signal for one line is accumulated in the line memory 210.
[0068]
The image processing circuit 211 includes a line memory control circuit 301 that controls input of pixel data from the line memory 210. When an image signal for one line is accumulated in the line memory 210, the line memory control circuit 301 inputs pixel data necessary for image processing of the image processing circuit 211 from the line memory 210 to the image processing circuit 211.
[0069]
The W data acquisition unit 302 acquires any pixel data (W data) of the first to nth pixels from the W line memory 210W. The RGB data acquisition unit 303 acquires any pixel data (R data, G data, B data) of the first to nth pixels from the R line memory 210R, the G line memory 210G, and the B line memory 210B. The data acquisition timing of the W data acquisition unit 302 and the RGB data acquisition unit 303 is controlled by the line memory control circuit 301.
[0070]
The multiplier 304 performs a predetermined multiplication process on the W data acquired by the W data acquisition unit 302. Specifically, a process of multiplying the W data acquired by the W data acquisition unit 302 by “3” (“W data” × “3”) is performed.
[0071]
The adder 305 performs a predetermined addition process on the R data, G data, and B data acquired by the RGB data acquisition unit 303. Specifically, a process of adding R data, G data, and B data acquired by the RGB data acquisition unit 303 (“R data” + “G data” + “B data”) is performed.
[0072]
Comparator 306 compares the operation result of multiplier 304 with the operation result of adder 305. Specifically, “W data” × “3” (hereinafter simply referred to as “3W”) that is the operation result of the multiplier 304 and “R data” + “G data” + that is the operation result of the adder 305. It is determined whether 3W = R + G + B, which is an expression for comparing “B data” (hereinafter simply referred to as “R + G + B”), is established.
[0073]
As a result of the comparison, if the above equation is established, a signal indicating that they coincide (hereinafter referred to as “establishment signal”) is output to the selector 307. On the other hand, if the above expression is not satisfied as a result of the comparison, a signal indicating that they do not match (hereinafter referred to as “failure signal”) is output to the selector 307.
[0074]
Here, the case where the establishment signal is output indicates that there is no color shift in the currently input pixel and that the pixel is an effective pixel. On the other hand, a case where a failure signal is output indicates that a color shift has occurred in the currently input pixel and that the pixel is an invalid pixel. The principle of the color misregistration will be described later.
[0075]
The selector 307 selects pixel data to be output to the memory 214 in accordance with a signal (establishment signal or non-establishment signal) from the comparator 306. The selector 307 includes the m-th pixel R, G, B data currently acquired by the RGB data acquisition unit 303 and the m-1-th pixel R, G, B acquired before the m-th pixel R, G, B data. B data is input. Note that the (m-1) th pixel R, G, and B data are stored in a one-pixel memory 308 described later. The selector 307 selects the former (m-th pixel R, G, B data) when a success signal is input from the comparator 306, while the latter (m-1 pixel R, R) when a failure signal is output. G, B data) is selected.
[0076]
The reason why the previously acquired pixel data is selected instead of the currently acquired pixel data when a failure signal is input is to prevent output of a pixel in which color misregistration has occurred. Thus, by replacing the currently acquired pixel data with the previously acquired pixel data, pixel data having the same color as the previously output pixel data can be output. As a result, it is possible to correct a color shift that has occurred in the currently acquired pixel data.
[0077]
The one-pixel memory 308 stores any data (m-th pixel R, G, B data or m−1-th pixel R, G, B data) selected by the selector 307 and output to the memory 214. Accordingly, the pixel data output last time to the memory 214 is stored in the one-pixel memory 308.
[0078]
Here, the principle of color misregistration occurrence will be described, and the principle of color misregistration correction of the reading unit 102 in the present embodiment will be described.
[0079]
FIG. 4 is a schematic diagram for explaining the principle of occurrence of color misregistration. FIG. 5 is a schematic diagram for explaining the principle of correcting color misregistration of the reading unit 102 in the present embodiment. 4 and 5 both show a case where a monochrome document is written on the board surface 101. FIG. Here, it is assumed that black pixel data and white pixel data are written. In FIG. 4, the reading unit 102 according to the present embodiment is described using an example in which white combined light is not turned on.
[0080]
FIG. 4 shows a case of reading a document written on the board surface 101 while moving the reading unit 102 in the sub-scanning direction, and particularly shows a case of reading three pixel data adjacent in the sub-scanning direction.
[0081]
FIG. 4 shows read data (0 to 9) obtained corresponding to reflected light from each pixel data. Here, three read data are obtained corresponding to each color, and in each read data, a large numerical value is obtained when the reflected light from the pixel data is large. That is, the maximum value “9” is obtained as the read data when the reflected light from the white pixel data is received.
[0082]
The lighting timing of each light source 205 is provided with a slight time difference in order to reduce power consumption. In the example of FIG. 4, first, the R light source 205R is turned on, then the G light source 205G is turned on, and then the B light source 205B is turned on. On the other hand, the reading unit 102 has moved in the sub-scanning direction. For this reason, there may occur a case where the original on the board surface 101 cannot be irradiated with all the R, G, and B monochromatic lights. In this case, color misregistration occurs.
[0083]
This will be described with reference to the example of FIG. When the light source 205 is located at the left position, all of the R, G, and B monochromatic lights are applied to the black pixel data. Since the irradiation destination is black pixel data, monochromatic light of R, G, and B is absorbed and the reflected light becomes small. For this reason, all the read data corresponding to the reflected light corresponding to the R, G, and B monochromatic lights are “0”. As a result, this pixel data is recognized as black pixel data.
[0084]
On the other hand, when the light source 205 is moved and the light source 205 is positioned at the center position, the R and G monochromatic lights are emitted to the black pixel data, while the B monochromatic light is emitted from the white pixel. Irradiated against data. Since the irradiation destination is black pixel data, the monochromatic light of R and G is absorbed and the reflected light becomes small, but the monochromatic light of B is not absorbed and the reflected light becomes large. Therefore, the read data corresponding to the reflected light corresponding to the R and G monochromatic lights is “0”, but the read data is “9” corresponding to the reflected light corresponding to the B monochromatic light. As a result, this pixel data is recognized as blue pixel data. That is, although it is black pixel data, it is recognized as blue pixel data, and color misregistration occurs.
[0085]
When the light source 205 is moved and the light source 205 is positioned on the right side, all the R, G, and B monochromatic lights are emitted to the white pixel data. Since the irradiation destination is white pixel data, the R, G, and B monochromatic lights are not absorbed and the reflected light becomes large. Therefore, all the read data corresponding to the reflected light corresponding to the R, G, and B monochromatic lights is “9”. As a result, this pixel data is recognized as white pixel data.
[0086]
FIG. 5 also shows the case of reading a document written on the board surface 101 while moving the reading unit 102 in the sub-scanning direction, as in FIG. 4, particularly when reading three pixel data adjacent in the sub-scanning direction. Shows about. Similarly to FIG. 4, read data (0 to 9) obtained corresponding to the reflected light from each pixel data is shown. Furthermore, in addition to these, it shows about the case where white synthetic | combination light (W) is lighted, and shows the comparison data (0-9) obtained corresponding to the reflected light of this synthetic | combination light.
[0087]
In the reading unit 102 of the present embodiment, the combined light is generated by turning on the light source 205R, the light source 205G, and the light source 205B within a time substantially equal to the lighting time of the monochromatic light from each light source 205. Specifically, white combined light is generated by dividing the lighting time of the light source 205R, the light source 205G, and the light source 205B into 1/3 each of the time when the monochromatic light is turned on. Then, the comparison data obtained corresponding to the reflected light of the white combined light is used as data for determining whether or not a color shift has occurred in the pixel data.
[0088]
In the reading unit 102 according to the present embodiment, it is determined whether a color shift has occurred in the pixel data by determining whether or not a certain relationship is established between the comparison data and the read data. . Here, the fixed relationship means a relationship in which a numerical value (3W) obtained by multiplying the comparison data by three (3 + W) and a numerical value (R + G + B) obtained by adding the read data match. If both numerical values match, it is determined that no color shift has occurred in the pixel data, and if they do not match, it is determined that color shift has occurred in the pixel data. Note that the determination of the occurrence of such color misregistration is performed by the comparator 306 described with reference to FIG.
[0089]
This will be described with reference to the example of FIG. The read data shown in FIG. 5 is the same as that shown in FIG.
[0090]
When the light source 205 is positioned on the left side, the combined light from the light source 205 is irradiated to black pixel data. Since the irradiation destination is black pixel data, the combined light from the light source 205 is absorbed and the reflected light becomes small. For this reason, the comparison data corresponding to the reflected light corresponding to the combined light from the light source 205 is also “0”. At this time, the numerical value (3W) obtained by multiplying the comparison data by three is “0”, and the numerical value obtained by adding the read data is also “0”. Therefore, it is determined that no color shift has occurred in the pixel data.
[0091]
On the other hand, when the light source 205 moves and the light source 205 is positioned at the center position, the combined light from the light source 205 is applied to the black pixel data, but the B monochromatic light is as described above. The white pixel data is irradiated. Since the irradiation destination is black pixel data, the combined light from the light source 205 is absorbed and the reflected light becomes small. For this reason, the comparison data corresponding to the reflected light corresponding to the combined light from the light source 205 is also “0”. At this time, the numerical value (3W) obtained by multiplying the comparison data by 3 is “0”, but the numerical value obtained by adding the read data is “9”. Therefore, it is determined that a color shift has occurred in the pixel data. In this case, the reading unit 102 replaces the pixel data with previously acquired pixel data in which no color misregistration has occurred.
[0092]
When the light source 205 moves and the light source 205 is positioned on the right side, the combined light from the light source 205 is emitted to the white pixel data. Since the irradiation destination is white pixel data, the combined light from the light source 205 is not absorbed and the reflected light becomes large. Therefore, the comparison data corresponding to the reflected light corresponding to the combined light from the light source 205 is “9”. At this time, the numerical value (3W) obtained by multiplying the comparison data by three is “27”, and the numerical value obtained by adding the read data is also “27”. Therefore, it is determined that no color shift has occurred in the pixel data.
[0093]
An example of color misregistration correction when the reading unit 102 according to the present embodiment specifically performs reading will be described. FIG. 6 is a diagram for explaining an example of color misregistration correction when the reading unit 102 according to the present embodiment specifically performs reading.
[0094]
FIG. 6A is a diagram illustrating pixels that can be read by the reading unit 102. In the figure, a case where seven readable pixels are arranged in each of the main scanning direction and the sub-scanning direction is shown.
[0095]
FIG. 6B is a diagram illustrating a document that is read with respect to the readable pixels illustrated in FIG. In the figure, one line reading direction is assigned to the main scanning direction.
[0096]
The document shown in the figure is pixel data in which all the pixels in the first to third columns from the left side and the first and second pixels from the bottom in the fourth column from the left side are black pixel data (hereinafter referred to as “black data”). Further, all the pixels in the first to third columns from the right side and the first pixel from the top in the fourth column from the right side (left side) are white pixel data (hereinafter referred to as “white data”). Furthermore, the second to fifth pixels from the top in the fourth column from the left side (right side) are pixel data in which black and white are mixed in the area of the pixel (hereinafter referred to as “mixed data”).
[0097]
Here, it is assumed that the mixed data is pixel data in which the blue color shift shown in FIG. 4 or 5 can occur. That is, it is assumed that the pixel data is when the monochromatic light of R and G is irradiated but the monochromatic light of B is not irradiated.
[0098]
FIG. 6C is a diagram illustrating the presence or absence of occurrence of color misregistration when reading is performed by the reading unit 102. When the occurrence of color misregistration in the reading unit 102 is examined in the manner shown in FIG. 5, the black data area and the white data area satisfy the above-described fixed relationship (3W = R + G + B), and the color misregistration. However, in the mixed data area, it is determined that the certain relationship is not satisfied and color misregistration has occurred. In the same figure, “existing” is indicated for pixels where color misregistration occurs, and “absence” is indicated for pixels where no color misregistration occurs.
[0099]
FIG. 6D shows read data when color misregistration is not corrected when color misregistration occurs as shown in FIG. In this case, as shown in the figure, the read original is correctly read for the black data area and the white data area, but the read original is not correctly read for the mixed data area. That is, in the mixed data area, the read data has a color shift. Here, the mixed data area is read as blue pixel data.
[0100]
FIG. 6E shows read data when color misregistration is corrected when color misregistration occurs as shown in FIG. In this case, as shown in the figure, the read original is correctly read for the black data area and the white data area. In addition to this, for the mixed data area, the read data replaced with the pixel data immediately before the main scanning direction of the mixed data area (second black data from the bottom in the fourth column from the left side) is read. Here, the mixed data area is read as black data replaced from blue pixel data.
[0101]
Hereinafter, the operation of the image processing circuit 211 of the reading unit 102 of the present embodiment that performs the color misregistration correction will be described. FIG. 7 is a flowchart for explaining the operation of the image processing circuit 211 of the reading unit 102 according to this embodiment.
[0102]
First, the image processing circuit 211 sets “1” to a counter (hereinafter referred to as “pixel number counter”) built in the line memory control circuit 301 in order to initialize the number of pixels to be read (n), and 1 pixel. White data is set in the memory (ST701).
[0103]
Next, the image processing circuit 211 monitors whether the read data of the nth pixel is stored in the line memory 210 (ST702). Here, it is monitored whether the read data of the first pixel corresponding to “1”, which is the value set in the previous ST701, is stored. Such a monitoring operation is performed by the line memory control circuit 301. If the read data of the nth pixel is not stored, the monitoring in ST702 is continued until the read data of the nth pixel is stored.
[0104]
If the read data of the nth pixel is stored, the image processing circuit 211 acquires R data, G data, B data, and W data of the nth pixel from the line memory 210 (ST703). Such acquisition operations are performed by the RGB data acquisition unit 303 and the W data acquisition unit 302, respectively.
[0105]
Next, the image processing circuit 211 performs a process of adding the acquired R data, G data, and B data (“R + G + B”) and a process of multiplying the acquired W data by “3” (“3W”) (ST704). ). Such arithmetic processing is performed by an adder 305 and a multiplier 304, respectively.
[0106]
Next, the image processing circuit 211 determines whether or not “3W = R + G + B”, which is an expression for comparing “3W” that is the operation result of the multiplier 304 with “R + G + B” that is the operation result of the adder 305, is established. Is determined (ST705). Based on this determination, it is determined whether the currently acquired pixel data (the nth pixel) is a valid pixel or an invalid pixel. Such comparison processing is performed by the comparator 306.
[0107]
If the currently acquired pixel is an effective pixel, the image processing circuit 211 outputs the R data, G data, and B data acquired in ST703 to the memory 214 of the overall control unit 201 as they are (ST706). The selection of the pixel data output in this way is performed by the selector 307.
[0108]
On the other hand, if the currently acquired pixel is an invalid pixel, the image processing circuit 211 outputs the pixel data stored in the one-pixel memory 308 to the memory 214 of the overall control unit 201 (ST707). As a result, the invalid pixel is replaced with the pixel data stored in the one-pixel memory 308.
[0109]
As will be described later, the pixel data output last time is stored in the one-pixel memory 308. However, if the read data of the first pixel is an invalid pixel, the pixel data output last time is stored. A situation that does not exist or a situation in which pixel data of a document that has been read remains before a document that is currently being read occurs. For this reason, in the image processing circuit 211, white data is set in the one-pixel memory 308 in ST701. As a result, even when the read data of the first pixel is invalid data, it is possible to prevent a color shift from occurring in the first pixel by replacing it with white data.
[0110]
As described above, according to the electronic blackboard 100 of the present embodiment, when an invalid pixel is detected in the first read pixel data, it is replaced with white data having the same color as the board surface 101. As a result, even in the case where the effective pixel detected before detecting the invalid pixel is replaced, it is possible to cope with the color shift generated in the pixel data of the first pixel.
[0111]
Next, the image processing circuit 211 stores the currently output R data, G data, and B data in the one-pixel memory 308 (ST708). That is, if the currently input pixel is a valid pixel, the R data, G data, and B data acquired in ST703 are stored, whereas if the pixel is an invalid pixel, it is stored in the one-pixel memory 308 until now. The stored R data, G data, and B data are stored again. Such storage processing is performed in conjunction with the output operation of the selector 307.
[0112]
Next, the image processing circuit 211 determines whether the value set in the pixel number counter is a value indicating the last pixel of the line in the main scanning direction recognized in advance (ST709). If it is not a value indicating the final pixel, the value of the pixel number counter is incremented by “1” (ST710), and the process returns to ST702. Then, the processing of ST702 to ST709 is repeated until the value set in the pixel number counter in ST709 reaches a value indicating the final pixel of the line. Here, since “1” is currently set, “2” is reset and the process returns to ST702.
[0113]
While repeating such processing, if the value set in the pixel counter in ST709 reaches a value indicating the final pixel of the line, the image processing circuit 211 reads up to the previously recognized final line in the sub-scanning direction. It is determined whether or not (ST711). If reading has not been completed up to the final line, the image processing circuit 211 returns the process to ST701. Then, the processing of ST701 to ST711 is repeated until it is determined in ST711 that reading has been completed up to the last line.
[0114]
While repeating such processing, if it is determined in ST711 that reading has been completed up to the last line, the image processing circuit 211 ends the reading processing.
[0115]
Here, the above-described pixel data replacement processing will be specifically described with reference to the read information shown in FIG. When the reading information shown in FIG. 6B is read, in the black data region arranged on the left side, “3W = R + G + B” is established in ST705 and is determined to be a valid pixel, so the R acquired in ST706 is obtained. Data, G data, and B data are output to the memory 214 as they are. As a result, black data is obtained as read data in the overall control unit 201.
[0116]
Such processing is repeated up to black data (second black data from the bottom of the fourth column from the left) immediately before the mixed data is processed. At the time when the black data immediately before the mixed data is processed, the R data, G data, and B data constituting the black data are stored in the one-pixel memory 308.
[0117]
Then, when the first mixed data (third mixed data from the bottom in the fourth column from the left side) is acquired, “3W = R + G + B” is not established in ST705, and it is determined as an invalid pixel. The R data, G data, and B data stored in 308 are output to the memory 214. At the same time, the R data, G data, and B data are stored in the one-pixel memory 308 again.
[0118]
Such processing is repeated until the last mixed data (second mixed data from the top in the fourth column from the left side), and all the mixed data is replaced with black data. As a result, black data is obtained as read data in the overall control unit 201.
[0119]
When invalid pixel data is detected in this way, the invalid pixel data is replaced with valid pixel data detected before the invalid pixel data is detected. Therefore, valid pixel data detected before the invalid pixel data is detected Pixel data replacement processing can be performed while referring to it, and correction of color misregistration that has occurred in the read original can be performed without a sense of incompatibility.
[0120]
Then, when the first white data (the uppermost white data in the fourth column from the left side) is acquired, “3W = R + G + B” is established in ST705, and it is determined to be a valid pixel, so the R data acquired in ST706. , G data and B data are output to the memory 214 as they are. As a result, white data is obtained as read data in the overall control unit 201. Such processing is repeated up to the last white data. As a result, the read data shown in FIG.
[0121]
As described above, according to the electronic blackboard 100 provided with the reading unit 102 of the present embodiment, the invalid pixel data is read while reading the color original recorded on the board surface 101 while moving the line sensor 105 and the like at a substantially constant speed. Since the effective pixel data can be replaced, the reading speed can be increased, and the inconvenience due to the difference in the reading positions of the R, G, and B colors in the RGB light source 205 can be eliminated.
[0122]
In particular, the invalid pixel data is detected according to the comparison result between the pixel data of each color read according to the monochromatic light by the image processing circuit 211 and the pixel data read according to the combined light, and the invalid pixel data is detected as the valid pixel data. Therefore, when the color original is read by the reading unit 102, invalid pixel data due to color misregistration can be easily identified, and the invalid pixel data can be reliably replaced with valid pixel data.
[0123]
Whether or not the sum (R + G + B) of the values corresponding to the pixel data of each color read according to the monochromatic light matches the triple value (3W) of the value corresponding to the pixel data read according to the combined light. Therefore, it is possible to easily determine whether the pixel data is invalid pixel data.
[0124]
In the present embodiment, the sum (R + G + B) of the values corresponding to the pixel data of each color read according to the monochromatic light is the triple value (3W) of the value corresponding to the pixel data read according to the combined light. The case where it is determined whether the pixel data is valid pixel data or invalid pixel data is described. However, the present invention is not limited to this, and the total sum of the values corresponding to the pixel data of each color read according to the monochromatic light is a value that approximates the triple value corresponding to the pixel data read according to the combined light. It is also possible to judge by When such a change is made, it is possible to give a certain range to the color misregistration comparison when reading a color original, and processing for detecting invalid pixel data more than necessary and replacing the invalid pixel data with valid pixel data. The effect that generation | occurrence | production of can be prevented is produced.
[0125]
FIG. 8 is a timing chart showing the relationship between the control for the light source 205 and the line sensor 105 and the output of the line sensor 105 in the reading unit 102 according to the present embodiment. FIG. 8 shows a timing chart for reading a document written in color.
[0126]
As shown in the figure, the reading unit 102 turns on the light source 205 in the order of white (W) combined light, R, G, and B monochromatic light. As described above, when the combined light is turned on, the R light source 205R, the G light source 205G, and the B light source 205B are turned on by 1/3 of the lighting time when the single color light is turned on.
[0127]
First, the reading unit 102 turns on the R light source 205 </ b> R for 1/3 of the lighting time of the R monochromatic light in order to turn on the combined light. Subsequently, the G light source 205G and the B light source B 205B are similarly turned on for a period of 1/3 of the lighting time of the G and B monochromatic lights. Simultaneously with the lighting control of the R light source 205R for lighting the combined light, a start pulse is output to the line sensor 105. In response to this start pulse, the line sensor 105 reads the reflected light from the board surface 101 by the combined light.
[0128]
When the lighting of the B light source 205B for turning on the combined light is finished, the reading unit 102 turns on the R light source 205R to turn on the R monochromatic light. At the same time, a start pulse is output to the line sensor 105. In response to this start pulse, the line sensor 105 reads the reflected light from the board surface 101 by the R monochromatic light. At this time, the read data obtained according to the reflected light from the board surface 101 by the combined light is output to the overall control unit 201 (W output).
[0129]
When the lighting of the R light source 205R for turning on the R monochromatic light is finished, the reading unit 102 turns on the G light source 205G to turn on the G monochromatic light. At the same time, a start pulse is output to the line sensor 105. In response to this start pulse, the line sensor 105 reads the reflected light from the board surface 101 by the G monochromatic light. At this time, read data obtained according to the reflected light from the board surface 101 by the R monochromatic light is output to the overall control unit 201 (R output).
[0130]
When the lighting of the G light source 205G for turning on the G monochromatic light is finished, the reading unit 102 turns on the B light source 205B to turn on the B monochromatic light. At the same time, a start pulse is output to the line sensor 105. In response to this start pulse, the line sensor 105 reads the reflected light from the board surface 101 by the B monochromatic light. At this time, read data obtained according to the reflected light from the board surface 101 by the R monochromatic light is output to the overall control unit 201 (G output).
[0131]
When the lighting of the B light source 205B for turning on the B monochromatic light is finished, the reading unit 102 turns on the R light source 205R again for 1/3 of the lighting time of the monochromatic light. Subsequently, the G light source 205G and the B light source B 205B are similarly turned on for a time that is 1/3 of the lighting time of the monochromatic light. Simultaneously with the lighting control of the R light source 205R for lighting the combined light, a start pulse is output to the line sensor 105. In response to this start pulse, the line sensor 105 reads the reflected light from the board surface 101 by the combined light. At this time, the read data obtained according to the reflected light from the board surface 101 by the B monochromatic light is output to the overall control unit 201 (B output).
[0132]
Thus, the read data obtained according to the reflected light from the board surface 101 by the combined light and the reflected light from the board surface 101 by the R, G, and B monochromatic light is output to the overall control unit 201. The period of one pixel for reading by the reading unit 102 is completed.
[0133]
As described above, according to the electronic blackboard 100 on which the reading unit 102 of the present embodiment is mounted, the R, G, and B monochromatic lights are divided and turned on within a time substantially equivalent to the monochromatic light lighting time of the RGB light source 205. To synthesize synthesized light. As a result, the combined light and the R, G, and B monochromatic lights can be turned on at substantially the same cycle, and the control of the RGB light source 205 is simplified.
[0134]
In particular, the synthesized light is synthesized by turning on each of the lighting times of R, G, and B monochromatic lights in the RGB light source 205 by 1/3. As a result, the combined light is combined by lighting by 1/3 of the lighting time of the R, G, and B monochromatic lights, so that the lighting time of each color can be made uniform.
[0135]
The reading unit 102 according to this embodiment turns on the combined light using the light source 205 in order to read the comparison data for correcting the color misregistration generated in the read data. This combined light is generated by dividing the lighting time in the case of monochromatic light in each color light source 205 (R light source 205R, G light source 205G or B light source 205G) into 1/3. The combined light is used in the reading unit 102 when reading a document written in monochrome.
[0136]
FIG. 9 is a timing chart showing the relationship between the control for the light source 205 and the line sensor 105 and the output of the line sensor 105 in the reading unit 102 according to the present embodiment. FIG. 9 shows a timing chart for reading a document written in monochrome.
[0137]
When reading a document written in monochrome, the reading unit 102 continuously turns on white (W) combined light using a light source 205 as shown in FIG. When the composite light is turned on, the R light source 205R, the G light source 205G, and the B light source 205B are turned on by one third of the lighting time when the single color light is turned on, as in the case of reading a document written in color. It is.
[0138]
In order to turn on the combined light, the reading unit 102 turns on the R light source 205R for a time that is 1/3 of the lighting time of the R monochromatic light. Subsequently, the G light source 205G and the B light source B 205B are similarly turned on for 1/3 of the lighting time of the G and B monochromatic lights. Simultaneously with the lighting control of the R light source 205R for lighting the combined light, a start pulse is output to the line sensor 105. In response to this start pulse, the line sensor 105 reads the reflected light from the board surface 101 by the combined light.
[0139]
When the lighting of the B light source 205B for turning on the combined light is completed, the reading unit 102 turns on the R light source 205R again for a period of 1/3 of the lighting time of the R monochromatic light. Subsequently, the G light source 205G and the B light source B 205B are similarly turned on for 1/3 of the lighting time of the G and B monochromatic lights. Simultaneously with the lighting control of the R light source 205R for lighting the combined light, a start pulse is output to the line sensor 105. In response to this start pulse, the line sensor 105 reads the reflected light from the board surface 101 by the previous combined light. At this time, the read data obtained according to the reflected light from the board surface 101 by the combined light is output to the overall control unit 201 (W output).
[0140]
In this way, the read data obtained in accordance with the reflected light from the board surface 101 by the combined light is output to the overall control unit 201, whereby the cycle of one pixel of reading by the reading unit 102 is completed.
[0141]
Thus, according to the electronic blackboard 100, the combined light is used when reading the information recorded in monochrome. As a result, the time required for reading can be shortened as compared with the case of sequentially switching and irradiating monochromatic lights of R, G, and B, and the monochrome can be accurately compared with the case of irradiating monochromatic light of G alone. It is possible to read the contents of the original document written in (1).
[0142]
Further, according to the electronic blackboard 100, the RGB light source 205 is sequentially turned on during the reading period of one line of the line sensor 105, and the combined light obtained by combining the single color light of the three colors R, G, and B with the single color light. Thus, the reading unit 102 using the RGB light source 205 can generate irradiation light suitable for both monochrome images and color images.
[0143]
In the present embodiment, the electronic blackboard 100 equipped with the reading unit 102 according to the present invention has been described. However, the reading unit 102 can be used for any device as long as it reads a color image. Can do. For example, the present invention can be applied to a copying machine that reads a color image. In this case, it can also be obtained in a copying machine or the like equipped with the effect of the reading unit 102 described above.
[0144]
【The invention's effect】
As described above, according to the present invention, it is possible to increase the reading speed, and it is possible to eliminate the inconvenience due to the difference in the reading position of each RGB light.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external configuration of a color electronic blackboard equipped with a reading device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a color electronic blackboard according to the embodiment.
FIG. 3 is a block diagram showing a configuration of an image processing circuit of the reading unit according to the embodiment.
FIG. 4 is a schematic diagram for explaining the principle of occurrence of color misregistration.
FIG. 5 is a schematic diagram for explaining the principle of correction of color misregistration of a reading unit in the embodiment.
FIG. 6 is a diagram for explaining an example of color misregistration correction when the reading unit according to the embodiment is specifically read.
FIG. 7 is a flowchart for explaining the operation of the image processing circuit of the reading unit according to the embodiment.
FIG. 8 is a timing chart showing the relationship between the control of the light source and line sensor and the output of the line sensor in the reading unit according to the embodiment (during color reading).
FIG. 9 is a timing chart showing the relationship between the control of the light source and line sensor and the output of the line sensor in the reading unit according to the embodiment (during monochrome reading).
[Explanation of symbols]
100 electronic blackboard
101 Board surface
102 Reading unit
103 Reading motor
105 Line sensor
201 Overall control unit
205 RGB light source
206 Light source control circuit
208 Line sensor control circuit
210 line memory
211 Image processing circuit
301 Line memory control circuit
302 W data acquisition unit
303 RGB data acquisition unit
304 multiplier
305 Adder
306 Comparator
307 selector
308 1 pixel memory

Claims (4)

An RGB light source that emits R, G, and B light toward the reading surface; a line sensor that receives reflected light from the reading surface and reads an image in pixel units; and the RGB light source along the reading surface; Moving means for moving the reading target on the reading surface at a substantially constant speed so as to pass the line sensor or the reading position of the line sensor, and lighting of the RGB light source during the reading period of one line of the line sensor Light source control means for generating four types of irradiation light of the three colors of monochromatic light of R, G, and B and the combined light that is lit and divided by 1/3 of the lighting time of the three colors of monochromatic light When the reading surface is read in color, the sum of the values corresponding to the pixel data of each color read according to the monochromatic light approximates the triple value corresponding to the pixel data read according to the combined light. If it is a value Outputs pixel data of each color using pixel data of each color read according to the monochromatic light as effective pixels, while a sum of values corresponding to the pixel data of each color read according to the monochromatic light is added to the combined light. If the pixel data read in response to the monochromatic light is not a value approximate to a value corresponding to three times the pixel data read in response, the pixel data of each color previously output as the effective pixel as the invalid pixel. And an image processing means for outputting after replacing with the above . 2. The reading apparatus according to claim 1 , wherein when the pixel data read first is an invalid pixel, the image processing unit replaces the pixel data with white pixel data and outputs the result. An electronic blackboard equipped with a self-propelled color sensor unit, and an RGB light source that irradiates light of R, G, and B toward a reading surface, and reflected light from the reading surface to receive an image in units of pixels A line sensor that reads the RGB light source and the line sensor along the reading surface, or a moving means that moves the reading target on the reading surface at a substantially constant speed so as to pass the reading position of the line sensor; During the reading period of one line of the line sensor, the lighting of the RGB light source is sequentially switched so that the lighting is divided by 1/3 of the lighting time of the three colors R, G and B and the lighting of the three colors. When the reading surface is read in color, the sum of values corresponding to the pixel data of each color read in accordance with the monochromatic light corresponds to the combined light. Read If the pixel data is a value approximate to three times the value corresponding to the pixel data, the pixel data of each color read according to the monochromatic light is output as the effective pixel, and the pixel data of each color is output according to the monochromatic light. If the sum of the values corresponding to the pixel data read in each color is not a value approximate to the triple value corresponding to the pixel data read in accordance with the combined light, each color read in accordance with the monochromatic light And an image processing unit that outputs the pixel data of each color as pixel data of each color that was previously output as an effective pixel . 4. The electronic blackboard according to claim 3 , wherein when the pixel data read first is an invalid pixel, the image processing means replaces the pixel data with white pixel data and outputs the result.

Images