JP2010021830A - Image reader, control method of image reader, and control program of image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve operability of document reading in an image reader which reads a document using a plurality of two-dimensionally arranged imaging elements. <P>SOLUTION: A region where a document A exists is detected by making some of pixel portions to be formed in light emission and imaging states as active pixels 10 among a plurality of pixel portions of a reading part 2. In the region where the document A exists, an image of the document A is read. In regions except the region where the document A exists, a region where a document different from the document A exists is detected. Thus, when a document B is newly loaded in the region except the region where the document A exists, the region where the document B exists is detected, and continuously, an image of the document B is read. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, an image reading apparatus control method, and an image reading apparatus control program, and more particularly to an image reading apparatus capable of reading a two-dimensional image, an image reading apparatus control method, and an image reading apparatus. It relates to the control program.

  An electrophotographic image forming apparatus (scanner function, facsimile function, copying function, printer function, data communication function, and MFP (Multi Function Peripheral) having a server function, facsimile apparatus, copying machine, etc.) A scanner (an example of an image reading apparatus) that reads an image from a document is provided.

  As a structure of a scanner, one that acquires a two-dimensional image by mechanically scanning a plurality of image pickup devices arranged in one dimension is common. There has also been proposed a scanner that reads an image in a short time using a two-dimensional contact area sensor without a mechanical movement mechanism. Such a scanner performs two-dimensional reading by arranging a plurality of pixels vertically and horizontally. One pixel area is divided into a light emitting area and a light receiving area. The elements in the light emitting area emit light, and the reflected light from the original is received by the elements in the light receiving area (photoelectric conversion unit), whereby image data in the pixel is acquired.

  Since such an apparatus does not require mechanical scanning, problems such as instability, durability deterioration, and noise associated with scanning can be eliminated, and the apparatus can be miniaturized. Therefore, these devices are attracting attention as new document reading devices.

  In a scanner that scans a one-dimensional sensor, a document size is detected by using a detection signal from a document size detection sensor or a detection signal read by a one-dimensional sensor.

  In a scanner using a two-dimensional contact area sensor, it is conceivable to read document information with a two-dimensional sensor unit for reading a document image and determine the size of the document based on the information.

  In Patent Document 1 below, a pixel included in an area sensor is provided with an EL (electroluminescence) element as a light source and a photodiode as a photoelectric conversion element, and the operation of the EL element and the photodiode is controlled by a TFT (thin film transistor). A close contact area sensor is described.

Patent Document 2 below discloses an image input / output device in which an image display unit is configured by a pair of transparent electrodes that sandwich liquid crystal, and a light receiving layer that receives light and converts it into an electric signal on the outer surface of the transparent electrode. Are listed.
JP 2001-292276 A JP-A-5-323275

  In terms of actual use, a two-dimensional sensor for reading a document image takes a long time to process signal charges for all pixels when reading the entire image at once due to the large number of read pixels. In the meantime, the user has to wait and there is a problem that the operability is poor. For example, if an A3 document is read at 600 dpi, processing of 75 million pixels is necessary if it is read at 1200 dpi.

  The present invention has been made to solve such a problem, and in an image reading apparatus that reads a document by using a plurality of two-dimensionally arranged pixel units, the operability of document reading is improved. It is an object of the present invention to provide an image reading apparatus, a method for controlling the image reading apparatus, and a control program for the image reading apparatus.

  In order to achieve the above object, according to one aspect of the present invention, an image reading apparatus is an image reading apparatus that reads a document using a plurality of pixel units arranged two-dimensionally, and each of the plurality of pixel units. Includes a photoelectric conversion unit that detects light from the document, and includes a detection unit that detects an area where the first document exists in the plurality of pixel units, and a first document detected by the detection unit. A reading unit configured to read an image of the first document in the region, and the detection unit includes a region where a second document different from the first document exists in a region outside the region where the first document exists. Is detected.

  Preferably, the detection unit sets a pixel portion at a specific position in an imaging state among the plurality of pixel portions, and detects the presence or absence of a document at the specific position based on the signal charge of the photoelectric conversion unit at the specific position.

  Preferably, the detection unit detects the position and size of the document by setting the pixel portions at a plurality of specific positions to an imaging state and detecting the presence or absence of the document at the plurality of specific positions.

  Preferably, the image reading apparatus detects the area where the first original is present, then reads the signal charge in the area where the first original is present, and the area where the first original detected by the detecting means is present. Reading of signal charges for document detection in the outer area is alternately performed.

  Preferably, the image reading apparatus performs reading of the first document and detection of the second document in parallel.

  Preferably, the image reading apparatus turns on the pixel portion at the outer edge of the area after detecting the area where the document exists.

  Preferably, each of the plurality of pixel units further includes a light source unit that irradiates the document.

  Preferably, the light source unit includes an electroluminescence element, and light emission thereof is controlled by a thin film transistor arranged for each pixel.

  Preferably, the light source unit includes a white backlight light source, a color filter, and a liquid crystal panel, and light emission thereof is controlled by a thin film transistor disposed for each pixel.

  According to another aspect of the present invention, a control method for an image reading apparatus is a control method for an image reading apparatus that reads a document using a plurality of pixel portions arranged two-dimensionally, and each of the plurality of pixel portions. Includes a photoelectric conversion unit that detects light from the document, and includes a first detection step that detects an area where the first document exists in the plurality of pixel units, and a first detection step that is detected in the first detection step. In the area where one original exists, the reading step for reading the image of the first original, and in the area outside the area where the first original detected in the first detection step, the first original is And a second detection step of detecting an area where a different second document exists.

  According to still another aspect of the present invention, a control program for an image reading apparatus is a control program for an image reading apparatus that reads a document using a plurality of pixel units arranged two-dimensionally. Each includes a photoelectric conversion unit that detects light from the document, and is detected in the first detection step and the first detection step of detecting a region where the first document exists among the plurality of pixel units. A reading step for reading an image of the first original in an area where the first original exists, and a first original in an area outside the area where the first original detected in the first detection step exists. Comprises a second detection step for detecting an area where a different second document exists.

  According to these inventions, in an image reading apparatus that reads a document using a plurality of two-dimensionally arranged pixel units, the image reading apparatus capable of improving the operability of document reading, a method for controlling the image reading apparatus, It is also possible to provide a control program for the image reading apparatus.

  Hereinafter, an image reading apparatus according to an embodiment of the present invention will be described. The image reading apparatus includes a plurality of imaging elements arranged in a two-dimensional manner. The image reading apparatus has a light source switching method (with a light source of R (red) → G (green) → B (blue) of equal magnification imaging (the resolution of the sensor (imaging device) itself is equal to the reading resolution of the document itself). A method of obtaining a color image by switching in order is employed. In other words, the image reading apparatus is a contact type two-dimensional image reading apparatus that reads image information of a document with an area type image sensor unit, and performs photoelectric conversion and image processing.

  The image reading apparatus includes a light-emitting layer, a light-emission control unit that controls light emission luminance and light-emission timing, a photoelectric conversion layer that detects reflected light of a placed document, and signal charges generated in the photoelectric conversion layer as image data. An image signal control unit for converting to (image signal) and processing.

  A photodiode is used as the image sensor. One pixel includes an EL element, a photodiode, and a thin film transistor. The light source need not be an EL element.

  FIG. 1 is a perspective view showing an external appearance of an image reading apparatus according to one embodiment of the present invention.

  Referring to the figure, an image reading apparatus 1 includes a reading unit 2 including a plurality of image pickup elements arranged in two dimensions.

  FIG. 2 is a plan view of the image reading apparatus.

  The reading unit 2 includes a plurality of pixel units 3. One pixel unit 3 includes a light source unit 4 and a sensor unit 5. The light source unit includes a RED light source, a GREEN light source, and a BLUE light source (each shown by different hatching).

  FIG. 3 is a diagram illustrating an outline of a cross-sectional configuration of the reading unit 2.

  The reading unit 2 is configured to sandwich the light source / sensor layer 8 between an ITO (indium tin oxide) layer 7 and a substrate 9 for power supply and control.

  At the time of image reading, power is supplied to the light source 4 of the light source / sensor layer 8 of the lighting target pixel, and the pixel is turned on. The generated light passes through the transparent ITO layer 7 and is irradiated onto the document 6 placed on the upper surface of the ITO layer 7. As a result, reflected light corresponding to the density of the document is generated.

  The sensor unit 5 of the pixel to be read receives reflected light from the original and generates a voltage corresponding to the reflected light by photoelectric conversion. A voltage generated at each pixel is detected, and a two-dimensional image of the document is reconstructed by the image processing unit.

  The light source unit 4 of each pixel unit 3 lights up three colors of red, blue, and green sequentially, and color reading is possible by detecting the voltage generated in the sensor unit 5 when the light of each color is turned on. .

  Regarding the lighting of the light source, only the light source of the reading target pixel may be turned on with respect to the reading target pixel, the light sources of the adjacent pixels may be turned on, or the light sources of all the pixels may be turned on.

  FIG. 4 is a block diagram illustrating a circuit configuration of the image reading apparatus.

  The reading unit 2 is provided with a plurality of pixel units 3 vertically and horizontally. Which pixel in the X and Y directions is caused to emit light by the column direction driving circuit 125 and the row direction driving circuit 127, which pixel in the X and Y directions is to be read, and which pixel in the X and Y directions is emitted. Whether to be in a standby state where neither reading nor reading is performed is controlled. The column direction driving circuit 125 and the row direction driving circuit 127 have a function of an image signal control unit that processes a signal charge generated in the photoelectric conversion layer of the pixel unit 3 as an image signal.

  In each pixel portion, a thin film transistor is arranged, and thereby light emission is controlled.

  Each of the column direction driving circuit 125 and the row direction driving circuit 127 is connected to the driving circuit 123 and driven by the CPU 121. That is, the reading unit 2 starts a reading operation in accordance with an external reading command, and the read data obtained thereby is output via the CPU 121.

  FIG. 5 is a block diagram illustrating a functional configuration of the signal processing unit of the image reading apparatus.

  The signal processing unit of the image reading apparatus includes a power supply unit 11 that supplies power to the reading unit 2 and a control unit 12 that controls the reading unit 2. The control unit 12 includes a control unit 13 that controls the reading unit 2, a document size detection unit 14, and an image processing unit 15.

  During normal document reading, an image read by the reading unit 2 is converted into image data by the image processing unit 15. When the document size is detected, the image read by the reading unit 2 is input to the document size detection unit 14 via the control unit 13. The document size detection unit 14 determines the document size area.

  The image processing unit 15 performs processing such as shading correction and edge enhancement. By not performing such processing in the document size detection unit 14, the document size can be determined at high speed.

  The control unit 12 is connected to a reading instruction unit 21 that receives a document reading instruction from a user. The reading instructing unit 21 includes a touch panel provided on the apparatus and buttons on an operation panel. When the reading instruction unit 21 is a button, the image of the document in the document detection area of the reading unit 2 is read by pressing the button.

  FIG. 6 is a diagram for explaining a document size detection state of the reading unit.

  The document size detection is executed before reading the document image. Among the plurality of pixel units of the reading unit 2, some of the pixel units are in the light emission and imaging state as the active pixels 10. Here, the active pixels 10 are pixel portions arranged in a plurality of vertical and horizontal directions with predetermined intervals in the vertical and horizontal directions. The arrangement of the active pixels 10 may be arbitrary.

  The active pixel 10 emits light with a luminance necessary to detect the presence or absence of a document at that position. This is a lower (darker) luminance than when reading a document image. This is because, as long as the presence / absence of a document is only detected, the amount of light is not as high as when a document image is read.

  By detecting the document size, the size of the document and the position where the document is placed are detected.

  7 to 10 are diagrams for explaining a procedure for continuously reading a plurality of document images.

  In the reading unit 2, as shown in FIG. 6, the pixel at a specific position is in the light emission / imaging state as the active pixel 10. In this state, it is assumed that the first original (original A) is placed on the left side of the reading unit 2 as shown in FIG. At this time, the signal charges of a part of the active pixels (active pixels under the document A) change.

  The document size detection unit 14 shown in FIG. 5 identifies the edge portion of the document A from the distribution of the pixels with the sensor output varying and the pixels without the variation. After the specification, in order to notify the user that the document size has been detected, the control unit 13 controls the pixels 16 around the edge portion of the document A as shown in FIG. For example, it is lit in orange). As a result, the user can confirm the area where the document is detected.

  After confirming the document detection area, the user issues a copy / scan instruction from the reading instruction unit 21. As a result, the control unit 13 enters an image data reading operation in the document edge detection area as shown in FIG. Pixels 17 around the outside of document A are lit in the color for the document reading area. Only the position where the document A exists (or even the position where the pixels 17 around the outside of the document exist) becomes the document reading area.

  In the reading unit outside the document reading area, the pixel at the specific position becomes the active pixel 10 and the document size can be detected. In this state, the user places the original B to be read next in an area where the original A does not exist on the reading unit 2 without removing the original A.

  Then, even when the document A is being read, the signal charges of some of the active pixels (active pixels below the document B) change. The document size detection unit 14 shown in FIG. 5 identifies the edge portion of the document B from the distribution of the pixels in which the sensor output varies and the pixels in which the sensor output does not vary. After the specification, in order to notify the user that the document size has been detected, the control unit 13 controls the pixels 16 around the edge of the document B as shown in FIG. For example, it is lit in orange).

  After confirming the document detection area, the user issues a copy / scan instruction from the reading instruction unit 21. As a result, the control unit 13 enters an image data reading operation in the edge detection area of the document B (this may be after the reading of the document A is completed). That is, the pixels around the outside of the document B are lit in the color for the document reading area. Only the position where the document B exists (or even the position where pixels around the outside of the document exist) becomes the document reading area. During this time, the user removes the original A that has been read. By removing the document A, a pixel at a predetermined position below the document A becomes an active pixel.

  FIG. 11 is a flowchart showing an image reading process executed by the control unit 12.

  In step S101, a pixel at a specific position of the reading unit 2 is turned on as an active pixel in a state where no document is placed, and an imaging state is set.

  In step S103, a change in the signal charge of the active pixel is detected. In step S105, the document edge position is specified from the distribution of the sensor output fluctuation pixels and the non-change pixels. As a result, an area where the document exists and an area where the document does not exist are determined. Here, the document area is detected from the fluctuation of the signal charge of the pixel between the state where the document is not placed and the state where the document is placed. However, the document is placed before step S101 is executed. Even when the document area is detected, the document area may be detected.

  In step S105, the periphery of the outside of the document edge is indicated to the user as the document detection area, so that the display is turned on.

  In step S107, the user confirms the document detection area, and determines whether the user has instructed copying (or scanning). If YES, the process proceeds to step S109, and if NO, the process returns to step S103 to repeatedly detect the document area and display the document detection area.

  In step S109, the lighting color of at least the outer periphery of the document detection area is changed as the document reading area. After the document reading, the document detection area is again set to the active pixel lighting / imaging state.

  In steps S103 to S109, outside the document reading area, the active pixel for document detection is in a lighting / imaging state.

  FIG. 12 is a timing chart showing control for reading signal charges from the reading unit 2.

  FIG. 12A shows the timing for reading image data in the first document area (area of document A in FIG. 10). FIG. 12B shows the timing for reading the image data of the first document area. FIG. 12C shows the timing at which the active pixel signal is read in the area outside the first document area in order to detect the size and position of the document outside the first document area. In the timing chart, reading and reading are performed during a period in which the signal is “H”. During the period when the signal is “L”, each reading and reading operation is stopped.

  Control for reading the signal charges photoelectrically converted by the sensor unit 5 of the pixel unit 3 is performed by the control unit 13. In order to achieve both the reading of the image data in the first document area (the area of document A in FIG. 10) and the size / position detection of the document outside the first document area (document B in FIG. 10), FIG. As shown in the timing chart, during the signal charge reading of the first document image data, interrupt control for reading the signal charge of the active pixel for document size detection is performed every predetermined time.

  More specifically, as shown in FIG. 12A, while reading the image data in the first document area at the timing (time T1 to T3), the reading is performed while FIG. The image signal is read (time T2 to T4) as shown in FIG.

  During the reading of the image signal, the reading operation is stopped for a certain period of time, and during the stop, the signal is read out from the active pixel (outside the first original area) as shown in FIG. Detection of original position and size). In other words, the image reading operation is intermittently stopped and the active pixel signal reading is executed in parallel.

  When the second original is placed in the active area outside the first original area in this way, the size detection and reading of the second original are performed in the same procedure as the first original thereafter. be able to.

  [Modification]

  In the above embodiment, when a document is placed on the reading unit 2 and the size of the document is detected, the periphery of the document is illuminated to indicate to the user that the document has been recognized (FIG. 8). As shown, the pixels 16 around the edge of the document A are turned on in the color for displaying the document detection area), but this process may be omitted.

  In addition, the image data reading operation is started when the copy instruction unit 21 issues a copy / scan instruction. However, even when there is no copy / scan instruction (or without receiving the copy / scan instruction), the predetermined time is reached. When the time has elapsed, the image data reading operation may be started. When the position and size of the document are detected, they are automatically read.

  As a technique for detecting the document size in the imaging state of the pixel at a specific position and reading the image information of only the document area, a so-called CMOS type that detects signal charges generated in the pixel portion as voltage data by switching is used. Signal processing is effective.

  [Effects of the embodiment]

  With the above configuration, in the contact type two-dimensional image reading apparatus having a plurality of pixels, it is possible to read the image information of the document partially (using only a part of the entire area) in the readable area. An area other than the area being read is set as a preparation area for reading the next document image. In the preparation area, the position and size of the document are detected.

  Thus, it is possible to read the next original immediately after the completion of the reading of the original, and to reduce the waiting time of the user at the time of reading.

  Further, in order to detect the presence and size of the placed document, a pixel at a specific position is brought into a light emission / imaging state, and detection signal information of the pixel is used. By setting only the pixel at a specific position to the light emitting / imaging state, energy loss can be suppressed, the time taken to determine the size can be shortened, and the user can be prevented from being dazzled.

  In addition, since only the detected range of the document is imaged, there is an effect that unnecessary light emission and reading need not be performed and unnecessary power can be reduced.

  Also, unlike the document image reading, the luminance of the light source for document detection is changed to a level at which document detection is possible (the amount of light is reduced), which has the effect of reducing wasted power.

  [Others]

  As the light source of the pixel portion, an electroluminescence element may be used, and light emission may be controlled by a thin film transistor disposed for each pixel, or a white backlight light source, a color filter, and a liquid crystal panel may be used for each pixel. The light emission may be controlled by a thin film transistor. That is, the present invention can be applied to an image reading apparatus of a type in which a liquid crystal display device includes a plurality of reading elements.

  The image reading apparatus may be provided in an image forming apparatus such as a monochrome / color copying machine, a printer, a facsimile machine, or a multifunction peripheral (MFP) thereof.

  The processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program may be downloaded to the apparatus via a communication line such as the Internet.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a perspective view showing an external appearance of an image reading apparatus according to a first embodiment of the present invention. It is a top view of an image reading apparatus. FIG. 3 is a diagram illustrating an outline of a cross-sectional configuration of a reading unit. It is a block diagram which shows the circuit structure of an image reading apparatus. It is a block diagram which shows the function structure of the signal processing part of an image reading apparatus. FIG. 6 is a diagram for explaining a document size detection state of a reading unit. FIG. 10 is a first diagram for describing a procedure for continuously reading a plurality of document images. FIG. 10 is a second diagram for describing a procedure for continuously reading a plurality of document images. FIG. 10 is a third diagram for describing a procedure for continuously reading a plurality of document images. FIG. 10 is a fourth diagram for describing a procedure for continuously reading a plurality of document images. It is a flowchart which shows the image reading process which the control part 12 performs. 3 is a timing chart showing control for reading signal charges from a reading unit 2;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Two-dimensional image reader 2 Reading part 3 Pixel part 4 Light source part 5 Sensor part 6 Manuscript 7 ITO layer 8 Light source / sensor layer 9 Substrate 10 Active pixel (light emission and imaging state pixel)
DESCRIPTION OF SYMBOLS 11 Power supply part 12 Control part 13 Control part 14 Document size detection part 15 Image processing part 16 Document detection display 17 Document reading display 21 Reading instruction | indication part

Claims (11)

An image reading apparatus that reads a document using a plurality of pixel units arranged two-dimensionally,
Each of the plurality of pixel units includes a photoelectric conversion unit that detects light from the document,
Detecting means for detecting an area where the first document is present among the plurality of pixel portions;
A reading unit that reads an image of the first document in an area where the first document detected by the detection unit exists;
The image reading apparatus is configured to detect an area where a second original different from the first original exists in an area outside the area where the first original exists.   The detection unit sets a pixel portion at a specific position in an imaging state among the plurality of pixel portions, and detects the presence or absence of a document at the specific position based on a signal charge of the photoelectric conversion unit at the specific position. Item 2. The image reading apparatus according to Item 1.   3. The image according to claim 1, wherein the detection unit detects a position and a size of a document by setting pixel portions at a plurality of specific positions to an imaging state and detecting the presence / absence of a document at the plurality of specific positions. Reader.   After detecting the area where the first original is present, reading the signal charge in the area where the first original is present, and the area outside the area where the first original is detected by the detecting means The image reading apparatus according to claim 1, wherein the reading of signal charges for document detection is alternately performed.   The image reading apparatus according to claim 1, wherein the reading of the first document and the detection of the second document are performed in parallel.   6. The image reading apparatus according to claim 1, wherein after detecting a region where a document is present, a pixel portion at an outer edge portion of the region is turned on.   The image reading apparatus according to claim 1, wherein each of the plurality of pixel units further includes a light source unit that irradiates the document.   The image reading apparatus according to claim 7, wherein the light source unit includes an electroluminescence element, and light emission is controlled by a thin film transistor arranged for each pixel.   The image reading apparatus according to claim 7, wherein the light source unit includes a white backlight light source, a color filter, and a liquid crystal panel, and light emission is controlled by a thin film transistor disposed for each pixel. A method for controlling an image reading apparatus that reads a document using a plurality of pixel units arranged two-dimensionally,
Each of the plurality of pixel units includes a photoelectric conversion unit that detects light from the document,
A first detection step of detecting an area where the first document exists among the plurality of pixel portions;
A reading step of reading an image of the first document in an area where the first document detected in the first detection step exists;
A second detection step for detecting a region where a second document different from the first document exists in a region outside the region where the first document exists detected in the first detection step; A method for controlling an image reading apparatus. A control program for an image reading apparatus that reads a document using a plurality of pixel units arranged two-dimensionally,
Each of the plurality of pixel units includes a photoelectric conversion unit that detects light from the document,
A first detection step of detecting an area where the first document exists among the plurality of pixel portions;
A reading step of reading an image of the first document in an area where the first document detected in the first detection step exists;
A second detection step for detecting a region where a second document different from the first document exists in a region outside the region where the first document exists detected in the first detection step; A control program for the image reading apparatus.

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