JP4977266B1 - Image reading apparatus and image reading method - Google Patents

Abstract

An image reading apparatus and an image reading method of the image reading apparatus are provided which reduce power consumption and are less likely to cause whiteout due to illumination.
An image reading apparatus includes an arm that can be expanded and contracted in a direction in which a distance between an imaging unit and a document placement surface (imaging surface) is changed, and the arm is provided with the imaging surface from an oblique direction. And a light source unit 105 for illuminating. The MPU turns off the LED 105 a that illuminates the outside of the illumination range among the LEDs 105 a to 105 d provided side by side in the longitudinal direction of the arm 102 as “light-off range 2”. Further, the MPU turns off the LEDs 105c and 105d close to the illumination range as [extinction range 1] when the illumination intensity of the illumination range is equal to or greater than a predetermined value.
[Selection] Figure 1

Description

  The present invention relates to an image reading apparatus that captures an image and an image reading method thereof.

  2. Description of the Related Art Conventionally, an image reading apparatus has been developed that captures an image of a document by arranging a photographing unit including an area sensor composed of a CCD, a CMOS, or the like above the document (for example, Patent Document 1). Recently, so-called “self-catering”, which scans a book for private use and reads it into a tablet PC or the like, has attracted attention, and is a market different from educational applications represented by conventional document cameras, Applications are expanding. The image reading apparatus disclosed in Patent Document 1 positions a document by abutting two sides of the document against a leg portion supporting the apparatus, and an imaging unit is fixed at an upper position of the document by an arm unit to scan a book or the like. Provide the intended structure.

  When capturing a still image such as the paper surface of a book, it is preferable that the image is taken with the entire paper surface illuminated by appropriate illumination.

  On the other hand, when shooting is performed by illuminating the paper surface from the same direction as the imaging unit, light reflected directly from the paper surface is incident on the imaging unit and the whitening phenomenon is likely to occur. Are known. The white-out phenomenon is a phenomenon in which the output of the image sensor of the photographing unit is saturated by strong incident light, and the image of that part becomes white and unclear.

  In addition, when the size of the shooting target changes, it is generally performed to change the distance between the shooting unit and the shooting target to adjust the size of the shooting target that appears in the shot image.

  In addition, it is important that the above-mentioned “self-cooking” can be easily performed. For example, many users feel troublesome to connect the image reading apparatus to a commercial power source. Therefore, it is desirable to adopt a configuration in which power is obtained from a USB terminal of a notebook PC or tablet PC to which an image reading apparatus is connected (so-called USB bus power). However, since the USB bus power is limited to a voltage of 5 V ± 5%, a current consumption of 500 mA, and a power consumption of 2.5 W, it is very important to reduce the power consumption of the image reading apparatus.

JP 2010-200291 A

  When adjusting the distance between the photographing target and the photographing unit in accordance with the change in the size of the photographing target, it is convenient that the distance between the photographing target and the light source unit can be adjusted at the same time so that the illumination extends over the entire photographing target. However, conventionally, there has been no image reading apparatus capable of simultaneously adjusting both of them while reducing power consumption.

  In addition, it is considered that both of the above can be adjusted at the same time by providing a light source unit in the photographing unit. However, in this configuration, there is a problem that the whiteout phenomenon is likely to occur as described above.

  An object of the present invention is to provide an image reading apparatus and an image reading method of the image reading apparatus that reduce power consumption and hardly cause a whiteout phenomenon due to illumination.

An image reading apparatus according to the present invention includes a photographing unit that captures a still image from a book , an arm that supports the photographing unit in a direction facing the book , and a boundary line between an inside angle and an outside angle of the photographing unit. A base part that supports and fixes the arm in a substantially parallel inclined state, a positioning part that aligns the center of the edge of the book provided on the base part, and the arm can be expanded and contracted without changing the inclined state An arm expansion / contraction section, a light source section that is provided on the arm to illuminate the book from an oblique direction, and moves with expansion / contraction of the arm expansion / contraction section , and an angle of view of the photographing section and the arm And a control unit that changes the light emission state of the light source unit based on a reading range that is variable by expansion and contraction of the light source and an illumination range that is variable by expansion and contraction of the arm of the light source unit.

Image reading method of the image reading apparatus of the present invention, the imaging unit to capture a still image while supporting in a direction which is opposed to the book from the book, which can expand and contract in the direction of changing the distance between the said imaging unit Books An arm, a base portion that supports and fixes the arm in an inclined state substantially parallel to a boundary line between the inside angle of view and the outside angle of view of the photographing unit, and the center of the edge of the book provided on the base portion A positioning unit for adjusting the position, an arm expansion / contraction part that allows the arm to be expanded / contracted without changing the tilted state, and provided on the arm to illuminate the book from an oblique direction, and with the expansion / contraction of the arm expansion / contraction part and moving the light source unit, an image reading method for an image reading apparatus and a variable to the reading range by the expansion and contraction of the arm while being defined by the angle of view of the imaging unit, the earth of the light source unit Stretch on the basis of the illumination range varied by the changes of the light emission state of the light source unit.

  According to the present invention, by changing the light emission state of the light source unit based on the illumination range in which the light source unit illuminates the imaging surface from an oblique direction, it is possible to reduce power consumption and to prevent the occurrence of a whiteout phenomenon.

1 is a perspective view illustrating an image reading apparatus according to an embodiment of the present invention. 1 is a block diagram showing the configuration of an image reading apparatus according to the present embodiment. The figure which shows an example of a structure of the height detection part of the image reading apparatus of this Embodiment. The figure which shows the relationship between the detection piece and photosensor in the expansion-contraction state of the upper arm of the image reading apparatus of this Embodiment Fig. 4 summarizes the arm expansion / contraction state and photo sensor output in Fig. 4 The figure which shows the structure of the detection piece of a shape where only the state of one sensor changes, when the state transition of the image reading apparatus which concerns on this Embodiment occurs The top view which shows an example of the state at the time of imaging | photography of the image reader which concerns on this Embodiment The figure explaining operation | movement of the image reading apparatus which concerns on this Embodiment. Explanatory drawing which shows the outline of the irradiation range of light at the time of moving a light source part with the expansion-contraction of the arm of the image reading apparatus which concerns on this Embodiment. FIG. 3 is a flowchart showing image reading processing of the image reading apparatus according to the present embodiment. The figure explaining the feature point detection process and conversion parameter generation process of the image reading apparatus which concerns on this Embodiment The figure explaining the state of the shadow which arises by illumination in the image reading apparatus which concerns on this Embodiment. Flow chart showing edge detection processing of the image reading apparatus according to the present embodiment

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

(Embodiment)
FIG. 1 is a perspective view showing an image reading apparatus according to an embodiment of the present invention. An image reading apparatus according to the present invention will be described with an example in which a book scanner for reading books and the like is embodied.

  As shown in FIG. 1, the image reading apparatus 100 extends in two directions from a photographing unit 101 that captures an image, an arm 102 that supports the photographing unit 101, a base unit 104 that supports the arm 102, and a base unit 104. It is mainly composed of two leg portions 103 and 103 that support the apparatus, and a light source portion 105 that illuminates the photographing range.

  The photographing unit 101 includes a camera 101a (see FIGS. 2, 8, and 9) that electrically captures an image. The camera 101a includes a camera lens 111 (see FIG. 2) and an imaging element 112 (see FIG. 2) that converts an image formed by the camera lens 111 into an electric signal and takes it in. The imaging device 112 is a two-dimensional (area) sensor such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor image sensor (CMOS image sensor). The photographing unit 101 is fixedly supported at an angle in which the camera 101a faces downward (a direction along a surface along the leg portions 103 and 103 (a direction facing the document placement surface 20; see FIG. 8 and the like)).

  Note that, when the imaging unit 101 is not in use, the imaging unit 101 rotates about a hinge provided on the upper arm 102a and can be stored in the upper arm 102a. As shown in FIG. 4, the upper arm 102a (the arm 102 in FIGS. 8 and 9) is fixed at a predetermined angle.

  The arm 102 includes a lower arm 102 b supported by the base unit 104 and an upper arm 102 a that supports the photographing unit 101. The lower arm 102b is fixedly supported at a predetermined angle by the base portion 104. The arm 102 is provided with an expansion / contraction mechanism that allows the length of the arm 102 to expand and contract. The expansion / contraction mechanism is specifically a slide mechanism. For example, a convex guide provided in the longitudinal direction (extension / contraction direction) of the upper arm 102a has a concave guide groove (in the extension / contraction direction) of the lower arm 102b ( Neither is shown) and is slidable in the longitudinal direction of the arm 102. The upper arm 102a slides relative to the lower arm 102b by applying a certain force or more, but if no force is applied, the sliding position is maintained.

  The slide mechanism of the arm 102 is provided with a stopper for locking the upper arm 102a and the lower arm 102b at a predetermined slide position. A plurality of positions are set as slide positions where the both are locked. With this configuration, the user can easily adjust the arm 102 to a plurality of prescribed lengths in a stepwise manner. The plurality of lengths of the books to be photographed are, for example, A4 size (for example, business document), A5 size (for example, textbook), A6 size (for example, library), B5 size (for example, weekly magazine), etc. Corresponding to the case of the prescribed size, it is set so that the reading range (view angle) of the photographing unit 101 can be moved to a height that is substantially the same as the prescribed book size.

  When the arm 102 is not in use, the arm 102 rotates about a hinge provided on the base 104 and can be folded to a position parallel to the legs 103, 103. Is fixedly supported by the base portion 104 at an angle of. The angle at which the arm 102 is supported is, for example, an angle at which the longitudinal direction of the arm 102 is inclined with respect to the vertical line when the image reading apparatus 100 is placed on a horizontal plane (for example, 30 ° to 60 ° with respect to the vertical line). , Preferably 40 ° to 50 ° or the like.

  Each of the leg portions 103 has a shape that is long in one direction, and one end of each of the leg portions 103 is connected to the base portion 104. When the image reading device 100 is placed on a horizontal plane, the legs 103 and 103 support the image reading device 100 by extending in two directions on the horizontal plane. The upper surfaces of the leg portions 103, 103 are made flat to form a substantial document placement surface 20 (see FIGS. 8 and 9), and a portion close to the base portion 104 has one end of the book to be photographed. Positioning marks 107 and 107 are provided to match the above.

  In addition, when not in use, the leg portions 103 and 103 are rotated around a support shaft provided on the base portion 104 and are folded together so that the leg portions 103 and 103 are parallel to each other. be able to. In use, it is opened at a predetermined angle (for example, 60 ° to 120 °, preferably 80 ° to 100 °, etc.).

  The base unit 104 is a base of the image reading apparatus 100. The base portion 104 supports the arm 102, and the two leg portions 103 and 103 are connected as described above. Further, the inner center end portion (the middle portion sandwiched between the leg portions 103 and 103) of the base portion 104 functions as a stopper 108 that is positioned by contacting one end of the book to be photographed.

  The light source unit 105 is provided on one surface of the upper arm 102a (the surface facing the document placement surface 20). The light source unit 105 includes a plurality of light emitting elements (for example, white LEDs: light emitting diodes) 105 a to 105 d, and the plurality of LEDs 105 a to 105 d are provided side by side along the longitudinal direction of the arm 102. The light source unit 105 changes the position up and down along with the upper arm 102 a when the arm 102 is expanded and contracted. Of course, the number of light emitting elements is not limited to four as illustrated, and may be increased or decreased.

  As described above, the image reading apparatus 100 according to the present embodiment supports the photographing unit 101 that performs photographing and the photographing unit 101 (document placement surface) in a direction facing the photographing surface, and the photographing unit 101 and photographing. An arm 102 that can be expanded and contracted in a direction in which the distance to the surface is changed; and a light source unit 105 that is provided on the arm 102 and illuminates the imaging surface from an oblique direction and moves as the arm 102 expands and contracts. The arm 102 is supported in an oblique direction with respect to the imaging surface, and the light source unit 105 is provided on the side surface of the arm 102. The arm 102 includes a lower arm 102b that is a fixed arm and an upper arm 102a that is a movable arm that can slide along the lower arm 102b. The light source unit 105 is provided on a side surface of the upper arm 102a. Yes. Since the light source unit 105 is provided on the side surface of the arm 102, the illumination of the light source unit 105 is irradiated from an oblique direction with respect to the paper surface of the book.

  Note that the light emitting elements 105a to 105d used in the light source unit 105 have a predetermined light amount distribution, and a part of light rays (light beams) can be irradiated in a direction orthogonal to the imaging surface due to this distribution. Further, the paper surface of a book generally forms a curved surface. Therefore, in consideration of these, the light source unit 105 in the present invention can be said to have a configuration in which “the optical axes of the light emitting elements 105a to 105d constituting the light source unit 105 are inclined with respect to the imaging surface”. The light source used in the light source unit 105 is not limited to a point light source such as an LED, but may be a surface light source such as an organic EL element. In such a case, “the main surface of the light source unit 105 including a light source ( It can be said that the normal line of the light emitting surface is inclined with respect to the photographing surface.

  Here, the irradiation angle at which the light source unit 105 irradiates the document placement surface 20 (see FIG. 8B) can be defined as follows. In the present embodiment, the irradiation angle is between the light emitted from the light source unit 105 (referring to the optical axis of the light emitting element or the normal line of the main surface of the light source unit as described above) and the document placement surface 20. Is equal to ½ (= θ1) of the angle of view of the camera 101a.

  In the image reading apparatus 100, when the light source unit 105 illuminates the document placement surface 20, the image reading apparatus 100 adjusts the illumination so as to irradiate from a predetermined oblique direction as well as adjusting the illumination so as to obtain an optimal amount of light. In other words, the image reading apparatus 100 adjusts so that the amount of light emitted from the light source unit 105 is optimal and is emitted from a predetermined oblique direction. In the case of adopting this configuration, the predetermined oblique direction is, for example, about 45 ° with respect to the paper surface (original placement surface 20) of the book 30. According to the present inventors, when the light source unit 105 irradiates the original placement surface with an angle of 45 °, the edge can be detected with high accuracy even when there is various external light. It could be confirmed.

  The irradiation angle of 45 ° is an example, and any irradiation angle may be used as long as the irradiation is performed from an oblique direction.

  FIG. 2 is a block diagram illustrating a configuration of the image reading apparatus.

  As shown in FIG. 2, an image reading apparatus 100 includes an MPU (Micro-Processing Unit) 120, a ROM (Read Only Memory) 121, a RAM (Random Access Memory) 122, an operation unit 123 including key buttons, a video input I, and the like. / F124 and video output I / F125. The MPU 120 includes an I / O-I / F 120a, and a USB (Universal Serial Bus) 126, a LAN 127, and a wireless LAN 128 are connected to the I / O-I / F 120a. The image reading apparatus 100 includes a height detection unit 131, a light source control unit 132, and a light source unit 105. The image reading apparatus 100 includes a DC power unit 141 that generates a predetermined DC power source from an external power source, and a battery 142 that is charged by the DC power unit 141 and supplies a DC voltage to each unit when the external power source is not connected. . As the external power source, USB bus power supplied through a USB cable can be used.

  The video output I / F 125 is, for example, HDMI (High-Definition Multimedia Interface). A display device 150 such as a digital TV is connected to the video output I / F 125. Alternatively, the display device 150 is an LCD (Liquid Crystal Display) display or an organic EL (Organic Electro-Luminescence) display mounted on the main body of the image reading apparatus 100.

  The USB 126, the LAN 127, and the wireless LAN 128 are connected to a personal computer (PC) 160 via each cable or wireless communication.

  The MPU 120 controls the entire image reading apparatus 100 and executes image reading processing including edge detection. In the MPU 120, the light source unit 105 illuminates the imaging target object from an oblique direction to generate a shadow portion at the end of the imaging target object, and obtains data that captures shooting data including the generated shadow portion via the video input I / F 124. Unit 201 and an edge detection unit 202 that detects an edge feature of the imaging object based on the captured image data. The edge detection unit 202 binarizes the shadow part and detects an edge feature. The edge detection unit 202 detects an edge feature when the binarized data is continuously generated in a predetermined number or more on the line of the end face of the imaging target. Details of the image reading process will be described later with reference to the flowcharts of FIGS.

  Furthermore, the MPU 120 executes control to change the light emission state of the light source unit 105 based on the illumination range in which the light source unit 105 illuminates the imaging surface 20 from an oblique direction. The MPU 120 changes the light emission state of the light source unit 105 by changing the light emission region by turning off part or all of the light source unit 105 and changing the light amount of part or all of the light source unit 105. Specifically, the MPU 120 turns off the LED (for example, the LED 105 a) that illuminates the outside of the illumination range among the LEDs 105 a to 105 d provided side by side in the longitudinal direction of the arm 102. Or the light quantity of LED105a is reduced. Further, when the illuminance of the illumination range is equal to or higher than the predetermined value, the MPU 120 turns off the LEDs (for example, the LED 105c and the LED 105d) that are close to the illumination range as [light-off range 1]. Or the light quantity of LED105c and LED105d is reduced.

  The ROM 121 is a read-only semiconductor memory that stores fixed functions such as programs and parameters for realizing various functions of the image reading apparatus 100 and image reading control.

  The RAM 122 is a so-called working memory that temporarily stores image data and calculation results. A part of the storage area of the RAM is backed up by a power source, or is configured by a nonvolatile memory such as an EEPROM (electrically erasable programmable ROM) or a flash memory, and retains setting conditions even after the power is turned off.

  The height detector 131 detects the height of the light source unit 105 provided on the side surface of the upper arm 102a. In the present embodiment, the light source unit 105 moves as the upper arm 102a expands and contracts. The moving position of the light source unit 105 that moves as the upper arm 102a expands and contracts is referred to as the height of the light source unit 105 and for convenience. An example of the configuration of the height detector 131 will be described later with reference to FIG.

  The light source control unit 132 selectively turns on / off a plurality of light emitting elements (here, the LEDs 105a to 105d). Furthermore, the light source control unit 132 controls the current supplied to the LEDs 105a to 105d to change the light emission intensity of each LED when it is turned on.

  FIG. 3 is a diagram illustrating an example of the configuration of the height detection unit 131. FIG. 3 is a diagram illustrating a relationship between a detection piece for detecting the expansion / contraction state of the arm 102 and the photo sensor.

  As shown in FIG. 3, the height detection unit 131 is attached to the upper arm 102a and is attached to the detection piece 135 that moves along with the expansion and contraction of the upper arm 102a, and the guide of the arm 102. It is composed of transmissive photosensors (interrupters) 136 and 137 that are not displaced. The interrupter has a configuration in which a light emitting element and a light receiving element are opposed to each other, and detects the presence or absence of a shielding object in an optical path between the light emitting element and the light receiving element.

  The detection piece 135 includes a protrusion 135a that detects the light transmission state of the photosensor 136 (hereinafter referred to as photosensor A) and a protrusion 135b that detects the light transmission state of the photosensor 137 (hereinafter referred to as photosensor B). Have. The detection piece 135 reciprocates in the direction D1 as the upper arm 102a expands and contracts. The photosensor A and the photosensor B are disposed to face each other at a position orthogonal to the reciprocating direction of the detection piece 135.

  FIG. 4 is a diagram illustrating the relationship between the detection piece 135 and the photosensors A and B when the upper arm 102a is expanded or contracted. In the following description, the output of the photosensor is “1” when the optical path of the photosensor A or B is blocked by the detection piece 135, and the output is “0” when the optical path is released (transmitted). Shall be.

  FIG. 4A shows the relationship between the detection piece 135 and the photosensors A and B when the arm 102 is in the most extended state. Photosensors A and B are both blocked by detection piece 135, and photosensors A and B output (1, 1) to light source control unit 132.

  FIG. 4B shows the relationship between the detection piece 135 and the photosensors A and B when the arm 102 is contracted by one step. Photosensor A is blocked by detection piece 135. The photo sensor B enters a transmissive state, and the photo sensors A and B output (1, 0) to the light source control unit 132.

  FIG. 4C shows the relationship between the detection piece 135 and the photosensors A and B when the arm 102 is further contracted by one step. The photo sensor A is in a transmissive state, and the photo sensor B is blocked by the detection piece 135. Photosensors A and B output (0, 1) to the light source controller 132.

  FIG. 4D shows the relationship between the detection piece 135 and the photosensors A and B when the arm 102 is contracted most. The photosensors A and B are both in a transmissive state, and the photosensors A and B output (0, 0) to the light source control unit 132.

  FIG. 5 is a table summarizing the expansion / contraction state of the arm 102 of FIG. 4 and the outputs of the photosensors A and B.

  As shown in FIG. 5, the light source control unit 132 can detect the expansion / contraction state of the arm 102 from the outputs of the photosensors A and B regardless of the length of the arm 102. For example, the light source control unit 132 can accurately recognize the expansion / contraction state of the arm by referring to the outputs of the photosensors A and B when the image reading apparatus 100 is turned on.

  Here, depending on the formation accuracy of the detection piece 135, the outputs of the photosensors A and B may be erroneously detected. As an example, when the photosensor output changes from A, B = 1, 0 to A, B = 0, 1, it may be erroneously detected that both the A and B outputs are switched. In this case, the detection piece 135 may be shaped so that only the state of one sensor changes whenever a state transition occurs.

  FIG. 6 is a diagram illustrating a configuration of the detection piece 138 having a shape in which only the state of one sensor changes when a state transition occurs.

  As shown in FIG. 6, the height detector 131A is attached to the upper arm 102a and moves with the expansion and contraction of the upper arm 102a, and the transmission type photosensors 136 and 137 attached to the guide of the arm 102. It consists of.

  The detection piece 138 includes a protrusion 138 a that detects the light transmission state of the photosensor A and a protrusion 138 b that detects the light transmission state of the photosensor B. The detection piece 138 reciprocates in the direction D1 as the upper arm 102a expands and contracts. The photo sensor A and the photo sensor B are disposed to face each other at a position orthogonal to the reciprocating direction of the detection piece 138.

  The detection piece 138 has a shape that changes such as photosensor outputs A, B = 1, 1 → A, B = 1, 0 → A, B = 0, 0 → A, B = 0,1. The light source controller 132 recognizes the expansion / contraction state of the arm 102 by detecting the pattern provided on the detection piece 138.

  In the present embodiment, the four states of the arm 102 are detected, but it can be configured to detect two states. In this case, one photo sensor is sufficient. Further, the expansion / contraction state of the arm 102 can be detected with a higher resolution. However, when the photosensors A and B (interrupters) are arranged corresponding to both ends of the detection piece 135, the amount of information is only 2 bits, so the number of states that can be detected is 4 or less. Therefore, in order to detect more than four states, it is desirable to employ a so-called reflector (reflective sensor) as a photosensor. By arranging a plurality of reflectors in a direction perpendicular to the moving direction of the detection piece 135 and separately coating the surface facing this with, for example, black / white, the resolution can be easily increased.

  Hereinafter, an operation of the image reading apparatus configured as described above will be described.

  First, the basic operation of the image reading apparatus will be described.

  FIG. 7 is a plan view illustrating an example of a state at the time of photographing of the image reading apparatus.

  As shown in FIG. 7, the image reading apparatus 100 is placed in a state where a book 30 to be photographed covers a part of the legs 103 and 103. The book 30 is positioned against the arc portion of the stopper 108. It is desirable that the positioning marks 107 and 107 have a positional relationship such that the extended line is in contact with the arc portion of the stopper 108. The positioning marks 107 and 107 may be simple marks, but may have a step structure in which the base portion 104 is raised. The alignment between the book 30 and the photographing unit 101 will be described later.

  At this time, the illumination of the light source unit 105 is applied to the paper surface of the book 30 from an oblique direction. In this state, the photographing unit 101 operates to capture a still image on the paper surface of the book. The user repeatedly captures the still image while turning the pages of the book 30, so that still images of a plurality of pages of the book 30 are sequentially captured. These still images are sent to the MPU 120 and converted into a planar and rectangular image in which the edge of the book 30 is corrected to a straight line by image processing.

  FIG. 8 is a diagram for explaining the operation of the image reading apparatus.

  FIG. 8A shows a state where the arm 102 is contracted, and FIG. 8B shows a state where the arm 102 is extended. In FIG. 8, the mounting surface of the image reading apparatus 100 is an XY plane (horizontal plane), and the direction extending in front of the image reading apparatus 100 (the horizontal component in the longitudinal direction of the arm 102) is the X direction. The height direction of 100 is taken as the Z direction. Note that FIG. 8 is drawn with the thickness in the Z direction of the leg portions 103, 103, etc. omitted for the sake of simplicity.

  When the image reading apparatus 100 is used, the arm 102 is supported by the support unit 104a at a predetermined angle (the same angle as the angle of view of the camera 101a). The support portion 104a includes a guide (not shown) that supports the arm 102 so as to be movable in the expansion / contraction direction, and the arm 102 moves along this guide.

  The effective reading range on the document placement surface 20 is P0 to PE1 (PE2) in the X direction, and this reading range is substantially defined by the angle of view (2 × θ1) of the camera 101a.

  In FIG. 8B, since the arm is extended as compared with FIG. 8A, the reading range is widened under the same angle of view.

  Hereinafter, FIG. 8 will be used in conjunction with FIG. 1 and FIG. The light source unit 105 is provided at an intermediate position in the extending direction of the arm 102. When the arm 102 (upper arm 102a) expands and contracts, the light source unit 105 moves up and down in conjunction with the upper arm 102a. The movement range of the light source unit 105 is Dz in the Z direction. The light source unit 105 includes a plurality of LEDs 105 a to 105 d arranged along the extending direction of the arm 102. The LEDs 105a to 105d can be individually turned on / off. The LEDs 105a to 105d may be configured such that the drive current is variable, or the ON duty ratio within a predetermined time set sufficiently shorter than the imaging cycle is variable (that is, PMW control is possible). Accordingly, for example, the light source control unit 132 in FIG. 2 can change the light amounts of the LEDs 105a to 105d by individually controlling the drive currents and ON duty ratios of the LEDs 105a to 105d. Similarly, the extinction range can be changed by individually extinguishing the LEDs 105a to 105d.

  Further, when an EL element is employed as the light source, for example, a plurality of individual electrodes (control electrodes) constituting the EL element are arranged side by side in the arm expansion / contraction direction. Since the light emitting area of the EL element is defined as the overlapping range of the individual electrode and the common electrode, by providing a driver for independently driving each individual electrode according to the arrangement of the individual electrodes, the light emitting element is equivalent to the LED The effect of can be obtained.

  The light source unit 105 mainly irradiates a range of P0 to PE1 (PE2) in the X direction. In this embodiment, since the light source unit 105 is provided in the middle of the arm 102, the height of the light source unit 105 differs between when the arm 102 (upper arm 102a) is contracted and extended. As a result, the light irradiation range is different.

  The light source unit 105 has a light extinction range 1 mainly from the viewpoint of whitening prevention and a light extinction range 2 from the viewpoint of power consumption reduction. The light source control unit 132 (see FIG. 2) of the image reading apparatus 100 individually sets the LEDs 105a to 105d in the extinction range 1 / extinction range 2 based on the height information of the light source unit 105 detected by the height detection unit 131. Implement the light source control to turn off. This light source control includes ON / OFF control of each of the LEDs 105a to 105d and light amount adjustment by drive current control. Further, the light source control unit 132 receives the instruction from the MPU 120 and determines whether light source control execution is appropriate.

[Light-off range 1]
As shown in FIG. 8A, when the arm 102 is contracted, the light source unit 105 comes down to a position close to the base unit 104. On the document placement surface 20, there is a stopper 108 which is a document position restricting portion at a position P0. Normally, the document is read by abutting the end of the document against the stopper 108 portion. The stopper 108 is close to the light source unit 105 (lower part). When the LED light source near P0 in the light source unit 105 emits light, the illuminance on the original surface around P0 becomes extremely high, and the output of the image sensor of the camera 102 is output. A whitening phenomenon occurs where the saturation occurs. In other words, the whiteout phenomenon is a phenomenon in which the contrast on the white side (high luminance side) becomes too strong and the dynamic range decreases. In order to prevent this, the LED light source (for example, LEDd or LEDc, LEDd (see FIG. 1)) in the extinction range 1 is extinguished. As a result, a whiteout phenomenon can be prevented and a dynamic range can be secured.

[Light-off range 2]
On the other hand, as shown in FIG. 8B, when the arm 102 is extended, the light source unit 105 moves upward according to the displacement of the arm 102. At this time, the light source unit 105 is controlled to light up to the lowest LEDd.

  ΔA1B1C1 shown in FIG. 8A and ΔA2B2C2 shown in FIG. 8B are similar. From this, FIG. 8B shows a state in which the arm 102 is extended at an angle θ where the line segment connecting PE1 corresponding to the maximum reading range in FIG. 8A and the uppermost end of the light source unit 105 intersects the X axis. ), A region where no light emission is required (light-out range 2) occurs at the upper end of the light source unit 102. Therefore, the LEDa (the LED included in the extinction range 2) located on the upper end side of the light source unit 105 is extinguished.

  Here, when the arm 102 is extended, the distance from the light source unit 105 to the PE 2 increases, and the amount of light attenuates in inverse proportion to the square of the distance. However, if it does so, the range which irradiates light exceeding PE2 in a X direction will be expanded. Therefore, if importance is placed on efficiency, the LEDs in the extinguishing range 2 are extinguished, and the LED in the light source unit 105 other than the extinguishing range 2 and near the extinguishing range 2 (that is, the upper LEDa as possible) is driven. The current may be selectively increased.

  As described above, the arm 102 expands and contracts along the guide supported by the support portion 104a. The guide is provided with transmissive photosensors A and B. On the other hand, the arm 102 is provided with a detection piece 135 (see FIG. 3) that moves as the arm 102 expands and contracts. The light source control unit 132 (see FIG. 2) recognizes the expansion / contraction state of the arm 102 based on the result of the height detection unit 131 (see FIGS. 2 and 3) detecting the pattern provided on the detection piece 135. Controls the LED on / off position.

  In particular, when the image reading apparatus 100 employs USB bus power or the like and does not have a sufficient power supply, reduction of power consumption is very important. The power consumption is mainly consumed by the light source unit 105. For this reason, reduction of power consumption of the light source unit 105 is required. In this embodiment, the power consumption is reduced by turning off the LEDs in the extinguishing range 2 and the extinguishing range 1.

  In the above, the light extinction range 1 / light extinction range 2 was demonstrated. Next, the offset and the irradiation angle of the light source unit 105 will be described.

  As shown in FIG. 8, in the image reading apparatus 100, the surface on which the legs 103 and 103 are placed becomes the document placement surface 20 on which the book 30 to be photographed is placed, and the photographing direction of the camera 101a (the light of the camera lens). Axial direction) is set substantially vertically downward.

  Further, among the angle of view of the camera 101a (indicated by a one-dot chain line in FIG. 8), the boundary line f on the arm 102 side is the expansion / contraction direction of the arm 102 (in this embodiment, the same as the longitudinal direction of the arm 102). It is set almost parallel. A boundary line f represents a boundary between the inside angle of view and the outside angle of view of the camera 101a.

  Further, the offset L (the line segment PC1-B1 in FIG. 8A and the line segment PC2-B2 in FIG. 8B) from the tip of the arm 102 to the camera 101a is placed on the original from the support portion 104a of the arm 102. The offset to the position P0 at one end of the surface 20 (FIG. 8A, line segment P0-C1 in B) is set to be almost the same. In other words, the offset L from the straight line along the expansion / contraction path of the arm 102 to the center of the camera lens of the camera 101a and the offset from the straight line to the position P0 at one end of the document placing surface 20 are substantially the same. Here, the offset represents a displacement amount and a displacement direction. The position P0 is a position where the end of the book abuts against the stopper 108 (see FIG. 7) or one side of the book aligned with the mark 107 (see FIG. 7) and the support portion 104a in the X direction. It is the position of the intersection with the straight line that extends to.

  As shown in FIG. 8A, when the arm 102 is contracted, the distance from the camera 101a to the document placing surface 20 is shortened, and therefore the reading range W1 of the camera 101a is decreased. On the other hand, as shown in FIG. 8B, when the arm 102 is extended, the distance from the camera 101a to the document placement surface 20 is increased, and therefore the reading range W2 of the camera 101a is increased.

  In FIG. 8A and FIG. 8B, the height of the camera 101a in the Z direction differs by a distance Dz. Further, in both cases, one end of the reading ranges W1, W2 of the camera 101a is fixed at the position P0, and the positions PE1, PE2 at the other end are changed. That is, even if the amount of expansion / contraction of the arm 102 is changed, the intersection of one end of the angle of view of the camera 101a and the document placement surface 20 is fixed at the position P0.

  Therefore, when adjusting the positions of the book 30 and the photographing unit 101, the user first places the book 30 on the document placement surface 20 with one end of the book aligned with the position P0. Subsequently, the user adjusts the amount of expansion / contraction of the arm 102 so that the paper surface of the book 30 fits within the reading range of the camera 101a. By only these adjustments, the user can adjust the photographing unit 101 and the book 30 to an appropriate distance and arrangement. Even if the size of the book 30 is different, the user can easily adjust the photographing unit 101 and the book 30 to an appropriate distance and arrangement in the same manner.

  Further, as shown in FIG. 8A, when the arm 102 is contracted, the light source unit 105 illuminates the document placement surface 20 from a low position. On the other hand, as shown in FIG. 8B, when the arm 102 extends, the light source unit 105 illuminates the document placement surface 20 from a high position.

  8A and 8B, the height of the light source unit 105 differs by a distance Dz. Therefore, the light source unit 105 can efficiently illuminate the small reading range W1 of the camera 101a if the arm 102 is contracted, and if the arm 102 is extended, the illumination range is expanded to illuminate the entire large reading range W2. Can do.

  Further, the light source unit 105 is provided along the inclined arm 102. The illumination of the light source unit 105 is applied obliquely to the document placement surface 20 regardless of the amount of expansion / contraction of the arm 102. Note that “irradiating obliquely” here means, for example, that the light emission axis of each of the light emitting elements 105a to 105d (see FIG. 1) constituting the light source unit 105 is inclined by θ1 with respect to the imaging surface. When the light source unit 105 is a surface light source such as an organic EL element, it means that the normal line of the light emitting surface is inclined by θ1 with respect to the imaging surface. This configuration has the following effects.

  (1) It is avoided that the direct reflected light of the illumination of the light irradiated on the document such as the book 30 (see FIG. 7) enters the camera 101a, and only the scattered light on the paper surface of the book 30 enters the camera 101a. The With the configurations of (1) and (3) described later, it is possible to avoid whiteout or smearing of an image mainly caused by saturation of the output of the image sensor, and the camera 101a can display a clean and accurate image. Can be captured.

  (2) The light source unit 105 is provided on the side surface of the arm 102 so as to illuminate the document placement surface 20 from an oblique direction (that is, the direction of θ1 (for example, 45 °)). On the other hand, the book 30 (see FIG. 7) placed on the document placement surface 20 has a thickness. For this reason, the irradiation light is incident on the document placement surface 20 from the light source unit 105 in an oblique direction, so that the edge of the book 30 (the outer shape portion of the book) is downward (that is, the document placement surface 20 side). A shadow is generated. On the other hand, since the camera 101a is in the normal direction of the document placement surface 20, it is possible to reliably capture a shadow caused by oblique irradiation. The image data including the shadow portion is captured by the MPU 120, and the MPU 120 performs binarization processing to detect an edge.

  As described above, the captured image data includes a shadow portion with the end of the paper surface of the book 30 as a boundary. The shadow portion becomes black data as a result of the binarization process, and is continuously generated on the end line of the book 30. Since the shadow portion is binarized, the accuracy of edge feature detection can be significantly improved. Since the edge of the paper surface of the book 30 can be reliably detected, detection accuracy is improved and extended in subsequent feature point detection processing (corner intersection detection processing, contour acquisition processing, other feature point detection processing, etc.). Can improve the accuracy of image reading.

  (3) Since the light source unit 105 is provided on the inclined arm 102 and is separated from the boundary line f on the arm 102 side in the X direction by the offset L, the light source unit 105 always has an angle of view of the camera 101a. Since it is arranged outside, it is avoided that the irradiation light of the light source unit 105 directly enters the camera lens of the camera 101a. Therefore, the camera 101a can capture a beautiful and accurate image.

  (4) In addition, the LED extinguishing in the extinguishing range 2 is basically performed from the viewpoint of reducing power consumption, but has the following effects. That is, when the LED in the extinguishing range 2 is lit, the light emitting area of the light source unit 105 is large, so that the shadow portion is less likely to occur when the document placement surface 20 is irradiated obliquely. By turning off the LEDs in the extinguishing range 2, the irradiation angle can be given.

  Next, the light irradiation range when the light source unit 105 is moved along with the expansion and contraction of the arm 102 will be described.

  FIG. 9 is an explanatory diagram showing an outline of the light irradiation range when the light source unit 105 is moved along with the expansion and contraction of the arm 102 in the image reading apparatus. FIG. 9A shows a state where the arm 102 is extended, and FIG. 9B shows a state where the arm 102 is contracted.

  In the state where the arm 102 shown in FIG. 9B is contracted, the reading range W1 in the X direction is between the position P0 and the position PE1 in relation to the angle of view. At this time, the lens shape on the front surface of the light emitting element, the LED drive current, and the like are determined so that the document surface illuminance at the position PE1 satisfies a desired value necessary for photographing with the camera 101a. At this time, the angle formed by the line connecting the uppermost part of the light source unit 105 to the position PE1 and the horizontal plane is defined as θ.

  By extending the arm 102 from this state, the reading range is expanded. In FIG. 9A, the reading range W2 in the X direction is between the position P0 and the position PE2. At this time, when a line segment having an angle θ is added from the position PE2 which is the outermost edge of the reading range W2, this line segment intersects the intermediate position (Pz) of the light source unit 105 instead of the uppermost part of the light source unit 105. That is, as the arm 102 is extended, the light source unit 105 also moves upward. However, the light source unit 105 moves more than necessary from the viewpoint of light irradiation range. At this time, the light emitted from the portion between the uppermost part of the light source unit 105 and the position Pz has a main illuminance distribution at a position PL that is outside the position PE2 on the horizontal plane. That is, it can be said that this portion is a region that emits useless light (referred to as a “loss region”). Of course, by extending the arm 102, the position PE2 which is the outermost edge of the reading range becomes farther away, so there is no doubt that the light emitted from the loss region also contributes to the increase in illuminance at the position PE2, but in terms of efficiency There's a problem.

  In the present embodiment, the loss area is set to the extinguishing range 2 and the LEDs in the extinguishing range 2 are extinguished.

  Next, an image reading process of the image reading apparatus will be described.

  FIG. 10 is a flowchart showing image reading processing of the image reading apparatus. It is executed by the MPU 120. In the figure, S indicates each step of the flow.

  In step S <b> 1, the MPU 120 inputs imaging data captured by the imaging unit 101.

  In step S2, the MPU 120 detects an edge from the imaging data. In the present embodiment, the illumination of the light source unit 105 is applied obliquely to the document placement surface 20 regardless of the amount of expansion / contraction of the arm 102. The imaging data includes a shadow portion generated downward from the edge of the book 30. By performing the binarization process on the shadow portion, the accuracy of edge feature detection can be significantly improved. The detailed flow of step S2 will be described later with reference to FIG.

  In step S3, the MPU 120 detects the document outline based on the edge detection. Specifically, the document contour detection is feature point detection processing such as corner intersection detection processing, contour acquisition processing, and other feature point detection processing. Note that the edge detection in step S2 may be included in one of the feature point detection processes.

  FIG. 11 is a diagram for explaining feature point detection processing and conversion parameter generation processing.

  As shown in FIG. 11A, in the feature point detection process, edge detection is performed on the captured image in the imaging region 300 to extract the contour of the book 30 that is the imaging target (hereinafter referred to as the document contour). Further, corner intersections of six main points (see ● marks) are detected based on the shape of the contour line, and their X and Y coordinates are specified. Further, as shown by a broken line in FIG. 11A, a document binding portion is extracted by linear component analysis of corner intersection detection, and the inclination of the document with respect to the X axis of the document placement surface is obtained. Similarly, the upper and lower lines are detected.

  In step S4, the MPU 120 generates a distortion correction parameter. The distortion correction parameter is obtained, for example, by generating a mesh structure. As shown in FIG. 11B, a mesh structure is generated, and coordinate data for projective transformation is extracted.

  In step S <b> 5, the MPU 120 performs image correction for performing plane development processing on the coordinate data of the projective transformation.

  In step S6, the MPU 120 generates display data whose image has been corrected.

  In step S7, the MPU 120 outputs the generated display data to the display device 150 via the video output I / F 125, and ends this flow.

  FIG. 12 is a diagram for explaining a state of a shadow generated by illumination in the image reading apparatus according to the present embodiment. FIG. 12 shows a state in which the book 30 is abutted against the position P0 of the stopper 108 serving as the document position restricting portion and has been placed on the document placement surface 20. Moreover, the state which contracted the arm 102 is illustrated.

  As already described, the light source unit 105 illuminates the book 30 from an oblique direction, and a shadow S1 is generated in PE1, which is the maximum reading range farther in the X direction from the support unit 104a. On the other hand, a shadow S0 is generated in P0 which is the maximum reading range closer to the X direction from the support portion 104a.

  Usually, in order to prevent the captured image from being lost, considering that the imaging range (angle of view) of the camera 101a is slightly larger, the shadow S1 generated in PE1 having a larger X coordinate value has a higher X coordinate value. The shadow is larger than the shadow generated at the small P0, and the shadow portion can be detected stably. Since the document outline of the book 30 is adjacent to the shadows S1 and S0, the edges constituting the outline can be detected more easily based on the shadow S1 than the shadow S0, and the detection accuracy is improved. As will be described later, in the present embodiment, first, an edge is detected based on the shadow S1, and the edge detection result of the shadow S1 is referred to when detecting an edge for the shadow S0, thereby improving the document outline extraction accuracy. ing.

  As described above, in the present embodiment, the lighting range of the light source unit 105 is changed according to the height of the arm 102. However, when the LEDs included in the extinguishing range 1 are turned on in FIG. There may be a situation where no occurs. In other words, it is important to determine the lighting range so that the shadow S0 is generated under the assumption of having the above-described edge detection process. That is, the present invention controls the lighting range (or the extinguishing range) of the light source unit 105 so that a shadow based on the contour of the subject (book 30) placed on the document placement surface 20 is generated. Including. The range of the light source to be turned on may be determined according to the height of the arm 102, or may be determined according to the detection state of the shadow S0 based on the image captured by the camera 101a.

  FIG. 13 is a flowchart showing the edge detection process. FIG. 13 is a subroutine of step S2 of FIG.

  In step S11, the data acquisition unit 201 acquires imaging data.

  In step S12, the edge detection unit 202 performs binarization processing on all imaging data.

  In step S13, the edge detection unit 202 detects an edge based on the binarized data, and in step S14, the edge detection unit 202 determines the edge by detecting the feature of the edge. The shadow portion becomes black data as a result of the binarization process. When this black data is generated on a line at the end of the book and continuously generated for a predetermined number or more, it is considered that an edge has been detected. In the present embodiment, the illumination of the light source unit 105 is irradiated obliquely (for example, 45 °) with respect to the document placement surface 20. As described above, since the shadow portion is binarized, the accuracy of edge detection can be significantly improved.

  Hereinafter, edge detection using shadows will be described in detail with reference to FIGS. 11 and 12 together.

  As shown in FIG. 11A and the like, since the book 30 has a thickness, the upper line 31a on the PE1 side in the captured image is often not a straight line, but has been described with reference to FIG. As described above, the edge detection accuracy is improved particularly on the side far from the document position restricting portion, and it becomes possible to accurately detect the upper line 31a of the book 30 which is an irregular shape.

  On the other hand, on the P0 side, the lower line 31b of the book 30 is often not a straight line (in FIG. 7, the lower line is drawn as a substantially straight line, but this is based on the viewpoint 107 and the stopper 108 in FIG. ) The shadow S0 is difficult to maintain a stable shape because of the light irradiation angle, and if only the shadow S0 is trusted, the edge detection accuracy of the entire lower line may be lowered. However, the stopper 108 is disposed in the P0 portion where the shadow S0 occurs, and the position of the book 30 itself can be easily specified by making the mark 107 a physical step. Furthermore, in the book, the shape of the upper line in P1 and the shape of the lower line in P0 are often line symmetric due to structural characteristics such as the strength of the back of the binding portion being particularly high. By taking these into account, if the shape of the upper line can be specified, it is possible to detect an accurate edge position by compensating the imperfection of the information source of the lower line based on this. In this embodiment, the document outline is extracted in this way.

  In addition, since the right (left) line 31c when the book 30 is opened is usually a straight line, it is not necessary to perform edge detection with high accuracy at all positions on the side.

  As described above in detail, the image reading apparatus 100 according to the present embodiment includes the arm 102 that can be expanded and contracted in the direction in which the distance between the imaging unit 101 and the document placement surface 20 (imaging surface) is changed, and the arm 102. And a light source unit 105 that illuminates the photographing surface from an oblique direction. The MPU 120 changes the light emission state of the light source unit based on the illumination range in which the light source unit 105 illuminates the imaging surface 20 from an oblique direction. For example, the MPU 120 turns off the LED (for example, the LED 105 a) that illuminates the outside of the illumination range among the LEDs 105 a to 105 d provided side by side in the longitudinal direction of the arm 102 as the “light-off range 2”. Further, when the illuminance of the illumination range is equal to or higher than the predetermined value, the MPU 120 turns off the LEDs (for example, the LED 105c and the LED 105d) close to the illumination range as [light-off range 1].

  According to the present embodiment, it is possible to reduce power consumption by turning off the LEDs in the extinguishing range 2 and the extinguishing range 1. In particular, when the image reading apparatus 100 does not have an independent power source such as USB bus power, it is very important to reduce power consumption.

  Further, by turning off the LED in the extinguishing range 1, it is possible to prevent a whiteout phenomenon and secure a dynamic range. As a result, the detection accuracy is improved in the subsequent feature point detection processing, and the accuracy of image reading can be improved.

  The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this.

  For example, the above embodiment employs a configuration in which the light source unit 105 attached to the arm 102 irradiates the document placement surface 20 with light from an oblique direction. As long as the light source unit 105 is an image reading apparatus that irradiates light on the document placement surface 20 obliquely, any arm configuration may be used.

  In the above-described embodiment, the light source unit 105 has been described as including a plurality of light emitting elements 105a. However, the light source unit 105 may include, for example, a single light emitting element. In addition, the light emitting element may be a dot-like or spherical element or a rod-like element. Further, when the light source unit 105 includes a plurality of light emitting elements, control may be performed to turn off only unnecessary portions and turn on only necessary portions as the arms extend and contract among the plurality of light emitting elements. . Moreover, the control which changes the light emission intensity of a light emitting element with the expansion-contraction of an arm may be performed.

  Moreover, in the said embodiment, although it was set as the structure which an arm expands and contracts by a slide mechanism, it is good also as a structure which an arm expands and contracts by various expansion / contraction mechanisms. In addition, a two-stage slide mechanism is provided on the arm, and the lower arm is fixedly supported, the middle arm that slides along the lower arm, and the upper arm that slides along the middle arm. It is good also as a structure to have. In this case, the light source unit may be provided in the middle arm, and the movement amount of the light source unit may be reduced by a predetermined ratio with respect to the movement amount of the photographing unit accompanying the expansion and contraction of the arm.

  In the above-described embodiment, the configuration in which the arm expansion / contraction direction is the direction along the boundary line f of the angle of view of the camera 101a has been described as an example, but the distance between the camera 101a and the document placement surface 20, As long as the distance between the light source unit 105 and the document placement surface 20 can be changed, the direction of expansion and contraction of the arm may be any direction.

  In the above-described embodiment, the configuration in which the longitudinal direction of the arm and / or the expansion / contraction direction of the arm is oblique to the document placement surface has been described as an example. For example, the longitudinal direction of the arm and / or the arm The expansion / contraction direction may be the vertical direction. In this case, the light source unit may be provided on the side surface of the arm with the light irradiation direction obliquely downward. Even in such a configuration, the light source unit can irradiate the original placement surface obliquely, and the illumination range of the light source unit can be changed to be larger or smaller as the arm extends and contracts.

  Further, in the above-described embodiment, an example has been described in which the paper surface of a book is an object to be photographed. However, the image reading apparatus of the present invention can also be applied to an object to be photographed other than a book.

  In the above-described embodiment, the names of the image reading apparatus and the image reading method are used. However, this is for convenience of explanation, and the apparatus may be a book scanner apparatus, an imaging apparatus, or the like. Etc.

  Further, each component constituting the image reading apparatus, for example, the type of MPU, its functional block, etc. is not limited to the above-described embodiment.

  Further, the functions of the data acquisition unit and the edge detection unit, which are characteristic configurations of the image reading apparatus of the present invention, may be installed anywhere. For example, it may be provided on the PC 160 side in FIG.

  The image reading apparatus and the image reading method described above are also realized by a program for causing the image reading apparatus and the image reading method to function. This program is stored in a computer-readable recording medium.

  The present invention can be applied to an image reading apparatus and an image reading method for photographing a paper surface of a book.

20 Document Placement Surface 30 Book 31a Upper Line 31b Lower Line 100 Image Reading Device 101 Imaging Unit 101a Camera 102 Arm 102a Upper Arm 102b Lower Arm 103 Leg 104 Base Unit 104a Support Unit 105 Light Source Unit 105a to 105d LED (Light Emitting Element)
107 Mark
108 Stopper 120 MPU
120a I / O-I / F
121 ROM
122 RAM
123 Operation unit 124 Video input I / F
125 Video output I / F
131, 131A Height detection unit 132 Light source control unit 135, 138 Detection piece 136, 137 Photo sensor 141 DC power unit 142 Battery 150 Display device 160 Personal computer (PC)
201 Data acquisition unit 202 Edge detection unit

Claims (8)

A shooting unit that captures still images from books ,
An arm that supports the photographing unit in a direction facing the book ;
A base portion that supports and fixes the arm in an inclined state substantially parallel to a boundary line between the inside angle of view and the outside angle of view of the photographing unit;
A positioning part for aligning the center of the edge of the book provided on the base part
An arm expansion / contraction section that allows the arm to expand and contract without changing the inclined state;
A light source unit provided on the arm to illuminate the book from an oblique direction and moves with expansion and contraction of the arm expansion and contraction unit ,
A control unit that changes a light emission state of the light source unit based on a reading range that is defined by an angle of view of the photographing unit and that is variable by expansion and contraction of the arm, and an illumination range that is variable by expansion and contraction of the arm of the light source unit When,
An image reading apparatus comprising:   The image reading apparatus according to claim 1, wherein the control unit changes a part or all of the light amount of the light source unit. The light source unit has a plurality of light emitting elements provided side by side in the longitudinal direction of the arm,
The image reading apparatus according to claim 1, wherein the control unit turns off the light emitting element that illuminates the outside of the reading range . The light source unit has a plurality of light emitting elements provided side by side in the longitudinal direction of the arm,
The image reading apparatus according to claim 1, wherein the control unit turns off the light emitting element close to the book when the illuminance by the light source unit is greater than or equal to a predetermined value. The arm includes a fixed arm and a movable arm that can slide along the fixed arm,
The image reading apparatus according to claim 1, wherein the light source unit is provided on a side surface of the movable arm. An arm that supports a shooting unit that captures a still image from a book in a direction facing the book, and that can be expanded and contracted in a direction that changes a distance between the shooting unit and the book ;
A base portion that supports and fixes the arm in an inclined state substantially parallel to a boundary line between the inside angle of view and the outside angle of view of the photographing unit;
A positioning part for aligning the center of the edge of the book provided on the base part
An arm expansion / contraction section that allows the arm to expand and contract without changing the inclined state;
An image reading method of an image reading apparatus, comprising: a light source provided on the arm and illuminating the book from an oblique direction, and moving along with expansion and contraction of the arm expansion and contraction unit ,
An image that changes a light emission state of the light source unit based on a reading range that is defined by an angle of view of the photographing unit and that is variable by expansion and contraction of the arm, and an illumination range that is variable by expansion and contraction of the arm of the light source unit. An image reading method of a reading apparatus. The image reading method of the image reading apparatus according to claim 6 , wherein the change in the light emission state is to turn off a light emitting element of the light source unit that illuminates the outside of the reading range . The image reading method of the image reading apparatus according to claim 6 , wherein the light emission state is changed by turning off a light emitting element of the light source unit that is close to the book when an illuminance by the light source unit is not less than a predetermined value.

Images