JPH06113081A - Picture reader - Google Patents

Abstract

PURPOSE:To provide pictures without blurs and distortion regardless of the degree of the contact of a platen glass and an original. CONSTITUTION:Distance between the original 5 and a solid-state image pickup element 3 is calculated at a spotlight position calculation part 12 based on the output of a photodetector 10 for spotlight which received the spotlight reflected at the original 5, the reading position of the original 5 by a picture reading part 1 is decided by the arithmetic processing of a microprocessor 19 based on the calculated result and the picture reading part 1 performs reading at the decided reading position. Also, at the time of reading the original, since a focus is appropriately adjusted based on an original shape calculated by the spotlight position calculation part 12, the clear pictures without the blurs and the distortion can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for forming an optical image of a document image on a solid-state image pickup device by using image-forming optical means and converting it into an electric signal, and more particularly to a solid-state image sensor for a document. The present invention relates to an image reading apparatus that improves image blurring caused by a change in the relative position of a document surface with respect to an image sensor and image distortion caused by the curvature of the document surface.

[0002]

2. Description of the Related Art As an image reading apparatus used in a facsimile, a digital copying machine, a scanner for a personal computer, etc., for example, as shown in FIG. 11, a housing 101 having a platen glass (not shown) on its upper surface is used. Original 10 on the upper side of
There is one in which 3 is arranged and the original image is read. An illumination light source 105, a mirror 107, a lens 109, and a solid-state image sensor (for example, CCD) 111 that configure a reduction optical system are installed in the above-mentioned housing 101.

Further, as another type of image reading apparatus, as shown in FIG. 12, an illumination forming an equal-magnification image forming optical system is provided in a housing 101 having a platen glass (not shown) on its upper surface. In some cases, the light source 105, the rod lens array 113, and the contact sensor 115 are installed. Then, the light emitted from the illumination light source 105 is reflected by the original 103, and the reflected light is imaged on the solid-state image sensor 111 or the contact sensor 115 via the reduction optical system or the same-magnification imaging optical system. The reflected light is converted into an electric signal according to the shading of the document surface.

In the above-described image reading apparatus, since the read signal is processed on the assumption that the entire original is in close contact with the platen glass, a book such as a book having a relatively large thickness is used. When the document is placed on the platen glass and scanned, the document surface near the spine of the book bends, so if no correction is made to the read image signal, the image of the characters etc. in that part is reduced There was a problem of becoming.

In order to solve such a problem, for example, in Japanese Patent Laid-Open No. 3-117965, a line beam is irradiated onto a document before the document is read, and the reflected light is read by a line sensor. -Detecting the degree of bending of the document, calculating the shape of the document, that is, the degree of floating from the platen glass, from this detection result, and subjecting the read image of the bent portion of the document to expansion processing based on this calculation result. Discloses that the image distortion generated in the bent portion of the document is eliminated.

[0006]

However, in the above-mentioned prior art, only the image distortion due to the bending of the original is corrected, and the deviation of the focus between the original reading sensor and the original surface due to the floating degree of the original from the platen glass. However, there is a problem in that an image is blurred and a document that is faithful to the document cannot be obtained. Further, in the case of an apparatus having a structure using a line beam light source that generates the above-mentioned line beam light, it is suitable for being incorporated in an image reading apparatus having a so-called reduction optical system because of its structure, but a so-called equal-magnification optical system. There is also a problem in that the image reading apparatus, which is downsized by using the system, is not suitable because the apparatus is upsized. Furthermore, in the above-mentioned conventional technique, when the document surface is floated from the platen glass, the document is read in a state where the document reading sensor surface and the document surface are not facing each other in the front, and the reading resulting from that is performed. There is a problem that the background portion of the document becomes dark due to the distortion of the document image and the shortage of the amount of light reaching the document reading sensor surface.

The present invention has been made in view of the above circumstances, and it is possible to obtain a clear image without blurring or distortion regardless of the degree of contact between the platen glass and the original, and moreover, an image suitable for downsizing of the apparatus. An object is to provide a reading device.

[0008]

In order to solve the above problems, an image reading apparatus according to the present invention according to claim 1 is an image forming optical means for forming an image of reflected light from a surface to be read at a predetermined position. An image reading device that detects an optical image formed at the predetermined position and converts the optical image into an electric signal; and a spot light irradiation unit that irradiates a desired position on the surface to be read with spot light. A reflected light receiving means for receiving the reflected light of the spot light applied to the surface to be read and converting it into an electric signal according to the amount of received light; and the imaging means based on the output signal of the reflected light receiving means. Position calculating means for calculating the distance between the light receiving surface of the image pickup means and the surface to be read, and both of these means while keeping the distance between the image forming optical means and the image pickup means constant based on the calculation result of the position calculating means. Adjust the position of the to the surface to be read Focus adjusting means, and the positions of the imaging optical means and the imaging means in the sub-scanning direction of the surface to be read based on the distance between the light receiving surface of the imaging means and the surface to be read calculated by the position calculating means. And a scanning position drive means for moving the imaging optical means and the imaging means in the sub-scanning direction of the surface to be read based on the determination result of the reading position determining means. It will be. An image reading apparatus according to a second aspect of the present invention is an image forming optical unit that forms an image of reflected light from a surface to be read at a predetermined position, and an optical signal formed by detecting the optical image formed at the predetermined position. In an image reading apparatus including an image capturing unit that converts the spot light into a desired position on the surface to be read, a spot light emitting unit that receives the spot light and a reflected light of the spot light that is applied to the surface to be read are received. And a position calculation means for calculating the distance between the light-receiving surface of the image pickup means and the surface to be read based on the output signal of the reflected-light receiving means When,
Focus adjusting means for adjusting the positions of the image forming optical means and the image pickup means with respect to the surface to be read while keeping the distance between the image forming optical means and the image pickup means constant based on the calculation result of the position calculating means,
A reading position that determines the positions of the imaging optical unit and the image pickup unit in the sub-scanning direction of the surface to be read based on the distance between the light receiving surface of the image pickup unit and the surface to be read calculated by the position calculation unit. Determining means, a scanning position driving means for moving the imaging optical means and the imaging means in the sub-scanning direction of the surface to be read based on the determination result of the reading position determining means, the calculation result of the position calculating means and the A normal direction calculating means for calculating normal directions at a plurality of reading points on the surface to be read based on the determination result of the reading position determining means; and the imaging optical means based on the calculation result of the normal direction calculating means. A direction adjusting means is provided for adjusting the directions of the image forming optical means and the image pickup means with respect to the surface to be read so that the optical axis coincides with the normal direction of the surface to be read.

[0009]

In the image reading apparatus according to the first aspect of the present invention, the reflected light of the spot light applied to the surface to be read has a different light receiving position in the reflected light receiving means depending on the curvature of the surface to be read. The light receiving position is determined by the output signal of the reflected light receiving means. Then, the distance between the surface to be read and the light receiving surface of the image pickup means is calculated by the position calculating means based on the data relating to the light receiving position, and the shape of the document is obtained from the result of the calculation. Then, the position in the sub-scanning direction of the imaging optical means and the image pickup means with respect to the surface to be read is determined by the reading position determining means according to the calculation result of the position calculating means, that is, the document surface shape, and based on this determination result. The imaging optical means and the imaging means are moved by the scanning position driving means, and the focus is adjusted by the focus adjusting means to read the surface to be read, and the surface to be read floats from the platen glass. Even if there is, it is possible to obtain an image that is faithful to the original without blurring or distortion. Further, in the image reading apparatus according to the second aspect of the present invention, in addition to the above-described operation, the normal direction calculating means calculates the normal directions at a plurality of reading points on the surface of the document to be read, and based on this calculation result. The image pickup means and the image forming optical means are driven by the direction adjusting means so that the optical axis of the image forming optical means coincides with the normal direction of the surface to be read. The image on the reading surface is read, and the image distortion caused by the floating of the surface to be read from the platen glass is removed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, referring to FIG. 1 and FIG.
An image reading device according to the described invention will be described. Here, FIG. 1 is a configuration diagram showing a configuration of an image reading apparatus according to the present invention, and FIG. 2 is an overall perspective view showing an embodiment of a schematic appearance of the image reading apparatus according to the present invention. This image reading device is roughly divided into an image reading unit 1 and a document position detecting unit 2. The image reading unit 1 includes a first drive processing circuit 4 for controlling the operation of the solid-state image pickup device 3, a solid-state image pickup device 3 as an image pickup device such as a CCD, and a reflection from a document 5 on the solid-state image pickup device 3. The first optical image forming system 6 including a lens for condensing light and the like.

The document position detecting section 2 includes a spot light source 7 for generating spot light, a rotary mirror 8 for reflecting the spot light from the spot light source 7, and the rotary mirror 8.
The spot light irradiation direction control unit 9 for controlling the rotation of the original, and the original 5 of the spot light emitted from the original 5 via the rotating mirror 8.
A second optical image forming system 11 for appropriately collecting the reflected light from the light receiving element 10 for spot light, and an optical image formed by the second optical image forming system 11 is read and converted into an electric signal. Spot light receiving element 1 as reflected light receiving means
0, a second drive processing circuit 13 for inputting a signal input from the light receiving element for spot light 10 to the spot light position calculation unit 12 at an appropriate timing and a signal level, and a second drive processing circuit 13 The spot light position calculating section 14 as a position calculating means for calculating the position of the spot light from the input output signal of the light receiving element for spot light 10 is provided. And in this embodiment,
The spot light source 7, the rotating mirror 8, and the spot light irradiation direction control unit 9 constitute a spot irradiation unit.

In the document position detecting section 2, particularly, the spot light source 7, the rotary mirror 8 and the second optical image forming system 11 are moved to read the document surface shape as described later. It has become so. And this move is
The position controller 23 and the position drive mechanism 24 are provided. That is, the position control section 23 generates a control signal necessary for operating the position drive mechanism section 24 based on a command from the microprocessor 19. The position drive mechanism section 24 has, for example, a motor (not shown) and a mechanism for converting the rotational force of the motor into a reciprocating motion.

The image reading apparatus further includes a document surface shape storage memory 15 for storing the calculation result of the spot light position calculation unit 12. The image reading apparatus also has a drive mechanism 17, an optical system position controller 16 and a pulse motor controller 18. Here, the drive mechanism 17 adjusts the movement of the image reading unit 1 in the sub-scanning direction (the direction of the solid arrow shown on the bottom of the housing 20 in FIG. 2) and the focus position of the optical system. The pulse motor control unit 18 controls driving of a pulse motor (not shown) used in the drive mechanism 17. The optical system position controller 16
The first optical imaging system 6 of the image reading unit 1 is driven by the drive mechanism 17.
So that the document is positioned at an appropriate focus position with respect to the document
A necessary control signal is output to the drive mechanism 17 based on a signal from the microprocessor 19. In this embodiment, the driving mechanism 17, the optical system position controller 16 and the pulse motor controller 18 constitute the scanning position driving means. Furthermore, this image reading device has a microprocessor 19. The microprocessor 19 controls the overall operation of the apparatus, and specifically controls the operation of the image reading section 1 and the like based on a program described later.

Next, the structure of the image reading apparatus according to the present embodiment will be described with reference to FIG. The image processing apparatus of this embodiment has
An image reading unit 1 including a solid-state image sensor 3 and a converging rod lens array 21 forming a part of the first optical imaging system 6 moves in a document reading direction (arrow direction in FIG. 2). The movable portion 2 ′ of the document position detecting section 2 is provided so as to be freely provided, and is located near the edge of the document and is movable in the document reading direction (arrow direction in FIG. 2). Here, the moving unit 2 ′ includes at least the spot light source 7, the rotating mirror 8, the spot light receiving element 10, and the second light.
It is sufficient that the optical image forming system 11 is housed, and it is not necessary to include other components of the document position detecting unit 2. Of course, there is no problem even if the entire document position detecting section 2 can be moved.

FIG. 3 shows the microprocessor 1 described above.
The contents of the series of image reading processing performed by
It is shown as a chart, and its contents will be described below with reference to FIG. Microprocessor 19
Detects the pressing of a reading start switch (not shown) (step 200) and starts a series of processes. Then, by driving the spot light source 7 to irradiate the spot light onto the original through the rotating mirror 8 (for example, a polygon mirror having a hexagonal column shape), and capturing reflected light from the original. , Spot light reading operation (step 2
02). The spot light reading process is performed while the document position detecting section 2 is moving in the arrow direction as shown in FIG. The spot light reading process is performed by reading the reflected light of the spot light from the document 5 every time the document position detection unit 2 moves at a constant interval d.

After the spot light reading, a calculation process (details will be described later) for calculating the document surface shape based on the acquired signal is performed (step 204), and further, based on this document surface shape calculation result. Then, the document reading position is calculated (details will be described later) (step 206). In the present embodiment, the reading position determining means is configured by the microprocessor 19 and step 206 executed by the microprocessor 19. Then, after this, the entire document is read (step 208). That is, the image reading unit 1 is moved to an appropriate reading position by the driving mechanism 17 based on the previous document reading position calculation result (step 206) (step 208a), and the first optical imaging system 6 is moved at each reading position. Focus adjustment is performed. This focus adjustment is performed on the original document surface shape calculation (step 204).
Specifically, the distance between the converging rod lens array 21 forming the first optical imaging system 6 and the solid-state imaging device 3 is kept constant, while the converging rod lens is performed. The distance between the array 21 and the original 5 is the data of the new original surface reading position (the data shown in FIG. 5C) which is obtained based on the result of the previous original surface shape calculation (step 204). And details will be described later) (208c). That is, the image reading unit 1 is moved up and down with respect to the document 5 and set at an appropriate position.

After the focus adjustment, one line is read (step 208e), then the process returns to the previous step 208a, and the reading for each remaining line is repeated. When the reading of the entire document is completed, the final read image is output.

Next, the document shape calculation process in step 204 described above will be specifically described with reference to FIG. In FIG. 4, a thick solid line in the upper part of the y-axis direction and a mountain-shaped part in the upper part of the figure indicate the degree of separation of the document 5 from the platen glass surface (hereinafter referred to as “document surface shape”). Is shown. In FIG. 2, the original surface shape is that when the edge of the original is viewed from a direction orthogonal to the original reading direction (the longitudinal axis direction of the housing 20 in FIG. 2). Lens 22 constituting the second optical imaging system 11
The spot light receiving element 10 is arranged such that the optical axis of the lens 22 is located at the center of the spot light receiving element 10.

In FIG. 4, the center of the light receiving element 10 for spot light is the origin O of the two-dimensional coordinates represented by the X and Y axes, and the lens 22 and the light receiving element 10 for spot light are used.
The distance between and is represented as f in the Y-axis direction. Here, the Y axis coincides with the optical axis of the lens 22. Further, the rotary shaft 8a of the rotary mirror 8 is provided in the front and back direction of the paper surface in FIG. 4, the distance from the origin in the X-axis direction is indicated by xm, and the reflecting surface from the origin in the Y-axis direction is shown. The distance (distance to the reflection surface of the spot light) is indicated by ym. Furthermore, the coordinates of the point on the reflecting surface of the rotating mirror 8 on which the spot light from the spot light source 7 is reflected are represented by M (xm, ym).

Then, assuming that the spot light incident on the reflection point M of the rotating mirror 8 is reflected at the reflection angle α and is incident on the original surface, the coordinates of the incident point P on the original surface are P (x, y). Shall be represented. The incident point P is also a reflection point at the same time, and the spot light reflected here passes through the lens 22 at an angle of β with respect to the Y-axis and the light receiving element 1 for spot light.
The light is incident on the surface of 0, and the incident point is represented by S (-xs, 0). Under the above conditions, the incident point P of the document 5
The value of the coordinate y, that is, the distance y between the light receiving element 10 for spot light and the original 5 is obtained.

First, the position xm of the rotary shaft 8a of the rotary mirror 8 in the X direction is represented by the side Pa of the triangle Pab (where point b is the center point of the lens 22) and the side Mc of the triangle PcM in FIG. Since it is calculated as the sum of the lengths of, it can be calculated by the following equation. That is, xm = (y−f) tan β
+ (Y-ym) tan α ... Expression 1 Also, tan β
= Xs / f ... Expression 2 can be expressed. Then, by expanding the above Expression 1 into an expression for y and substituting the relationship of Expression 2, the following Expression 3 can be obtained. y = (xm + ym · tan α + xs) / (tan α + xs / f) ... Equation 3

This calculated value is stored in the memory 15 for storing the document surface shape.
Is stored in the image reading unit 1 and is read through the microprocessor 19 during focus adjustment (see step 208c in FIG. 3) in the reading process of the entire original image by the image reading unit 1, and the distance between the image reading unit 1 and the original 5 is determined. It will be used as data when calculating.

Next, regarding the document reading position calculation in step 206 of the flow chart shown in FIG. 3, FIG.
This will be described with reference to (c) and FIG. The calculation of the document reading position means that the position of the image reading unit 1 in the sub-scanning direction is the document surface shape previously obtained (step 2 in FIG. 3).
04 and refer to FIG. 5 (b)). First, FIG. 5A shows the actual shape of the document surface when the document is viewed from the same position (direction orthogonal to the document reading direction) as shown in FIG. On the other hand, FIG. 6B shows an approximate shape of the document surface obtained by plotting the values of the document surface shape calculated based on the detection result of the document position detecting unit 2.

Then, the document surface reading position is specifically calculated as described below. First, in FIG.
Among the diagrams showing the document surface shape shown in (b), in particular, the diagram in which the portion where the document floats from the reference surface (the surface of the platen glass) is enlarged is shown. In the figure, x _i-1 represents a point on the document that matches the reference plane,
In addition, the interval at the time of reading the document is d (the moving distance when the moving unit 2 ′ moves at a constant interval in the spot light reading process described above), and l ₁ from x _i−1 to the document surface The distance to the upper point P _i . Furthermore, the coordinates (x
n, yn) (where n = 0, 1, 2, ...) is a point Pn (n = 0, 1, 2, ...) Obtained by the prescan by the moving unit 2 ′. is there.

The document reading position to be obtained, that is, the position of the image reading unit 1 when the image reading unit 1 reads the document 5 is defined as Qn (n = 0, 1, 2, ...). Here, it is assumed that the point Qn is represented by coordinates (x'n, y'n). Under such assumption, from the point P ₀ to P _i-1, in order to have close contact with the platen glass, the point P ₀ to P
_i-1 coincides with the points Q _{0 to} Q _i-1 , that is, x ₀ , x ₁ , ... X _i-1 which are the X coordinates of each point are x ′ ₀ , x ′ ₁ ...
• x'i _-1 will be matched respectively.

Next, since the point P _i is floating from the platen glass, the document reading position is determined not as the point P _i but as the point Q _i as follows. Now, let's assume we l _1> d, at the point Q _i is the line segment _{P i P i-1, P} i-1 Q i
= D, and its coordinates are (x ' _i ,
_y'i) to become. Next, since the point P _{i + 1} is also floating from the platen glass, the document reading point is not the point P _{i + 1} but the point Q _{i + 1} . This point Q _{i + 1} is obtained as a point that follows the line segment Q _i P _i and becomes the line segment Q _i Q _{i + 1} = d. If d> line segment Q _i P _i , Line segment P _i P
_{i + 1} on those obtained by the point becomes a line segment Q _i Q i _{+ 1} = d in. The coordinates of the point Q _{i + 1} are (x ′ _{i + 1} , y ′
_{i + 1} ). Hereinafter, the points after the point Q _{i + 2} are also obtained in the same manner as described above. The value of y ′ at each point Q, which represents the floating of the document from the platen glass, is obtained by substituting the coordinate x ′ into the approximate expression obtained by performing the line approximation of the document shape using the point P. It is a thing.

The original surface reading position Qn thus obtained is the point where each point is located in the reference surface direction when it is assumed that the original floating from the reference surface is extended along the reference surface. It can be said that the reading positions Qn are equivalent to each other, and the read positions Qn thus obtained are unequal intervals due to the calculation method (see FIG. 5C).

FIG. 7 shows a flow chart showing the procedure of the above-mentioned document surface reading position calculation process. The document surface reading position calculation process will be described in brief with reference to FIG. First, the distance between two points of interest on the polygonal line is obtained (step 300). In the example described above, this is the distance between the start point xo and the point P _i and the point P _i and the point P _{i + 1.}
The calculation of the distance between and corresponds to the calculation of the distance on the broken line.

After calculating the distance on the polygonal line (step 300), the distance on the plane is calculated (step 302). In the example described above, corresponds to the distance calculation in the plane referred to herein is a portion calculated by prorating the distance between the _x'i and x'i _{+ 1.} Finally, coordinate calculation is performed (step 304). That is, in the example described above, the starting point x
This is equivalent to calculating the distance from o.

In this embodiment, the shape of the original 5, that is, the floating state of the original 5 from the platen glass is obtained by using the original position detecting unit 2, and the sub-scanning direction is determined according to the degree of the floating of the original 5. Since the position of the image reading unit 1 is determined and the original 5 is read at an appropriate focus position at that position, as compared with the conventional one in which the read original image is expanded based on the original shape, The read image is always obtained at the in-focus position, so that an image faithful to the original without blurring and distortion can be obtained.

Next, an image reading apparatus according to the second aspect of the present invention will be described with reference to FIGS. Here, FIG. 8 is a configuration diagram showing a configuration example of the image reading apparatus according to the invention of claim 2, and FIG. 9 is a mechanism of the moving section 2 ′ and the image reading section 1 of the image reading apparatus shown in FIG. FIG. 10A is a schematic diagram of the mechanical configuration of the moving unit 2 ′, FIG. 11B is a schematic diagram of the mechanical configuration of the image reading unit 1, and FIG. 6 is a flowchart for explaining the procedure of image processing in the image reading apparatus.

The image reading apparatus according to the second aspect of the present invention has the same main part as the image reading apparatus according to the first aspect of the present invention, and is shown in FIG. 1 in the configuration shown in FIG. The same components as those described above are designated by the same reference numerals and detailed description thereof will be omitted, and the following description will be focused on different points. This device is shown in FIG.
The optical system vertical position control unit 25, the vertical position drive mechanism unit 26, the optical system direction control unit 27, the direction drive mechanism unit 28, the pulse motor control unit 29, and the horizontal position drive mechanism as shown in FIG. And a section 30.

The optical system vertical position control unit 25, together with the vertical position drive mechanism unit 26, adjusts the distance between the solid-state image pickup device 3 and the first optical imaging system 6 with respect to the original document 5. The control signal necessary for moving the first optical imaging system 6 to the desired position is output to the vertical position drive mechanism unit 26. The vertical position drive mechanism unit 26
Although not shown in the drawing, for example, the motor and the rotational force of this motor are used to change the relative positions of the solid-state image pickup device 3 and the first optical imaging system 6 with respect to the original 5.
And a mechanism for converting into relative movement between the first optical imaging system 6 and the original 5.

In the optical system direction control section 27, the direction drive mechanism section 28 controls the solid-state image pickup device 3 and the first optical imaging system 6 to move to the first direction.
The control signal necessary to rotate the optical image forming system 5 so that the optical axis of the optical image forming system 5 coincides with the normal line at the reading point of the document 5 (details will be described later) is output. Directional drive mechanism 28
Has a function as described above, and although not shown, it has, for example, a motor and a mechanism for converting the rotational force of the motor into a rotational movement at an appropriate speed. Is. The optical system direction control section 27 and the direction drive mechanism section 28 constitute a direction adjusting means. Pulse motor control unit 2
Reference numeral 9 is for outputting a control signal necessary for the horizontal position drive mechanism section 30 to move the solid-state imaging device 3 and the first optical imaging system 6 in the sub-scanning direction (the direction of the solid arrow in FIG. 2). .

The horizontal position drive mechanism section 30 has the above-mentioned function, and converts the pulse motor 36 (see FIG. 9B) and the rotational force of the pulse motor 36 into a horizontal reciprocating motion. And a mechanism for doing so. Figure 9
The vertical position drive mechanism 26 and the direction drive mechanism 28
Also, a specific configuration example of the horizontal position drive mechanism unit 30 is shown, and the content thereof will be described below with reference to the same drawing. First, FIG. 1A shows an example of the configuration of the moving unit 2 ', which includes at least the spot light source 7, the rotary mirror 8, the spot light receiving element 10 and the second light. The optical imaging system 11 is stored in a storage box 31. The storage box 31 is provided in the position drive mechanism unit 2
4 is moved in the direction indicated by the white arrow in FIG.

On the other hand, in the image reading section 1, at least the solid-state image pickup device 3, the first optical image forming system 6 and the light source 32 are housed in a rotary housing box 33 (see FIG. 9B). The rotation storage box 33 is supported by the base portion 34 so as to be rotatable around a shaft 35.
8, the base portion 34 is rotated within a plane including the so-called sub-scanning direction in which the base portion 34 moves (the direction of the white arrow in FIG. 9B) (see the solid arrow in FIG. 9B). . Further, the solid-state image sensor 3 and the first image forming system 6 are moved up and down (upward and downward in the plane of FIG. 9B) by the above vertical position drive mechanism section 26 in the rotary storage box 33. As a result, the distance from the original 5 can be changed to adjust the focus. And
The base portion 34 rotatably holds the rotary storage box 33 as described above, and the base portion 34 itself is the pulse motor 3.
A horizontal position drive mechanism unit 30 having 6 is movable in the sub-scanning direction as shown in FIG.

FIG. 10 is a flowchart showing the procedure of a series of image reading processing performed by the microprocessor 19.
The contents will be described below with reference to FIG. The flow chart shown in FIG.
Steps having the same contents as those of the operation in FIG.
The difference from the operation by the flowchart shown in FIG. 3 will be mainly described. First, in step 207, calculation of the document surface normal direction is performed. This is the image reading unit 1.
In order to make the optical axis of the first optical imaging system 6 coincide with the optical path of the reflected light from the original 5 when reading the original in FIG.
Is for calculating the direction (angle) in which the optical axis of the optical imaging system 6 should be directed (details will be described later). In this embodiment, this step 207 and this microprocessor 19 constitute a normal direction calculating means.

In step 208d, the optical system direction is adjusted. That is, the previous step 207
Based on the data in the direction normal to the document surface calculated by
The solid-state image sensor 3 and the first optical imaging system 6 are oriented in the normal direction of the original 5. As a result, the optical axis of the first optical imaging system 1 coincides with the optical path of the reflected light from the document 5, and the document is always read from the front side of the document 5. Next, the calculation of the document surface normal direction in step 207 will be specifically described with reference to FIG.

[0039] In the figure, for example, be described as an example a case of calculating the normal direction at the point Q _i, the two-dot chain line passing through the point Q _i in the figure, the normal direction at the point Q _i The angle between the two-dot chain line and the dotted line drawn perpendicularly to the X axis from the point Q _i (hereinafter, referred to as “normal angle”).
γ _i is calculated by the following equation. That is, γ _i = ta
It is calculated as n ⁻¹ ((y _i −y _i ⁻¹ ) / (x _i −x _{i −1} )). This normal angle is calculated for each document reading position Q _i , Q _{i + 1} , Qi + 2 ... Calculated in step 206, and the calculated angle data is stored in the document surface shape storage memory 15. Memorized in. Then, the angle data stored in the document surface shape storage memory 15 is input to the optical system direction control unit 27 via the microprocessor 19 to control the direction drive mechanism unit 28. A signal is generated and input to the direction drive mechanism unit 28, whereby the rotary storage box 33 is rotated by the normal angle γ and the optical axis of the first optical image forming system 6 is aligned with the original surface. It coincides with the normal direction, that is, the optical path of the reflected light from the document.

The overall operation of the image reading apparatus according to this embodiment will be described generally. First, when a start switch (not shown) is pressed, the storage box 31 moves by a fixed distance d, The original 5 is irradiated with spot light, and the shape of the original 5 is calculated based on the reflected light. Further, the position at which the document is read by the image reading unit 1 and the direction of the normal to the document surface are calculated based on the data of the document surface shape. After that, the base portion 34 moves to the document reading position calculated previously, and the solid-state imaging device 3 and the first optical image forming system 6 are moved up and down with respect to the document 5 by the vertical position drive mechanism unit 26 to focus. Adjustments are made. Then, the rotary storage box 33 is rotated based on the previously calculated normal angle, and the optical axis of the first optical imaging system 6 is aligned with the normal direction of the original surface. The original 5 is read.

In the embodiment of the image reading apparatus according to the present invention, the normal angle on the document surface is calculated,
The first optical imaging system 6 and the solid-state imaging device 3 are provided with a rotary storage box 3
The optical axis of the first optical imaging system 6 is set in the normal direction of the original surface by housing the rotary storage box 33 in accordance with the calculated normal angle. That is, since it matches the optical path of the reflected light from the document, the document image can be captured from the front, and a high-quality read image without distortion can be obtained.

[0042]

As described above, according to the image reading apparatus of the first aspect of the present invention, the shape of the original is obtained by irradiating the original with spot light before reading the original. The original shape is determined by determining the position to read the original surface based on the original shape and reading the original, and at the time of reading, focusing is performed based on the original shape data. In comparison with the conventional device that calculates the image and performs the expansion process of the image based on this, it is not necessary to perform the expansion process that takes a lot of time for the signal processing, and the structure of the device is simplified. As a result, the effect is obtained that an image faithful to a document without blurring or distortion can be obtained. Claim 2
According to the image reading apparatus of the invention described above, the orientations of the imaging optical means and the imaging means with respect to the surface to be read are adjusted so that the optical axis of the imaging optical means coincides with the normal direction of the surface to be read. With this configuration, since the image is read from the front side of the surface to be read, even if the surface to be read is floating from the platen glass, distortion of the image due to the floating does not occur. That is the effect.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a configuration of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is an overall perspective view showing an example of a schematic appearance of an image reading apparatus according to the present invention.

FIG. 3 is a flowchart for explaining an image processing procedure in the image reading apparatus according to the present invention.

FIG. 4 is an explanatory diagram illustrating a process of calculating a document shape by a document position detection unit in the image reading apparatus according to the present invention.

FIG. 5 is a characteristic diagram illustrating the relationship between the reading position of a document in the sub-scanning direction and the position of the document surface from the reference surface, for explaining calculation of the document reading position in the image reading apparatus according to the present invention.

6 is a characteristic diagram in which a raised portion of a document is enlarged in the characteristic diagram shown in FIG.

FIG. 7 is a flowchart schematically showing a procedure for calculating a document surface reading position.

FIG. 8 is a configuration diagram showing a configuration of an image reading apparatus according to an embodiment of the present invention.

9 is a schematic diagram showing a mechanical schematic configuration of a document position detecting unit and an image reading unit of the image reading apparatus shown in FIG. 8, and FIG. 9A is a schematic diagram of the document position detecting unit; Figure (b)
FIG. 3 is a schematic diagram of an image reading unit.

FIG. 10 is a flowchart for explaining a procedure of image processing in the image reading apparatus shown in FIG.

FIG. 11 is a schematic configuration diagram showing an example of a conventional image reading apparatus.

FIG. 12 is a schematic configuration diagram showing another example of a conventional image reading apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image reading part, 2 ... Original document position detection part, 2 '... Moving part, 3 ... Solid-state imaging device, 7 ... Spot light source, 8
... Rotating mirror, 10 ... Spot light receiving element, 12
... Spot light position calculation unit, 16 ... Optical system position control unit,
17 ... Drive mechanism, 18 ... Pulse motor control unit, 2
4 ... Position control unit, 24 ... Position drive mechanism unit, 25 ... Optical system vertical position control unit, 26 ... Vertical position drive mechanism unit,
27 ... Optical system direction controller, 28 ... Direction driving mechanism,
29 ... Pulse motor control unit, 30 ... Horizontal position drive mechanism unit

Claims (2)

[Claims] 1. An image forming optical unit for forming an image of reflected light from a surface to be read at a predetermined position, and an image pickup unit for detecting an optical image formed at the predetermined position and converting the optical image into an electric signal. In the image reading apparatus, the spot light irradiating means for irradiating the desired position on the surface to be read with the spot light, and the reflected light of the spot light applied to the surface to be read are received and the amount of the received light is adjusted. Reflected light receiving means for converting into an electric signal, position calculating means for calculating the distance between the light receiving surface of the image pickup means and the surface to be read based on the output signal of the reflected light receiving means, and operation of the position calculating means Based on the result, focus adjusting means for adjusting the positions of the image forming optical means and the image pickup means with respect to the surface to be read while keeping the distance between them constant, and the image pickup means calculated by the position calculating means. The light-receiving surface of the Read position determining means for determining the positions of the image forming optical means and the image capturing means in the sub-scanning direction of the surface to be read based on the distance from the surface to be read, and the image formation based on the result of the determination by the read position determining means. An image reading apparatus comprising: a scanning position driving unit that moves the optical unit and the image pickup unit in the sub-scanning direction of the surface to be read. 2. An image forming optical unit for forming an image of reflected light from a surface to be read at a predetermined position, and an image pickup unit for detecting an optical image formed at the predetermined position and converting the optical image into an electric signal. In the image reading apparatus, the spot light irradiating means for irradiating the desired position on the surface to be read with the spot light, and the reflected light of the spot light applied to the surface to be read are received and the amount of the received light is adjusted. Reflected light receiving means for converting into an electric signal, position calculating means for calculating the distance between the light receiving surface of the image pickup means and the surface to be read based on the output signal of the reflected light receiving means, and operation of the position calculating means Based on the result, focus adjusting means for adjusting the positions of the image forming optical means and the image pickup means with respect to the surface to be read while keeping the distance between them constant, and the image pickup means calculated by the position calculating means. The light-receiving surface of the A reading position determining unit that determines the positions of the image forming optical unit and the image capturing unit in the sub-scanning direction of the surface to be read based on the distance from the surface to be read, and the result based on the determination result of the reading position determining unit. Scan position driving means for moving the image optical means and the image pickup means in the sub-scanning direction of the surface to be read, and a plurality of readings on the surface to be read based on the calculation result of the position calculation means and the determination result of the reading position determination means. A normal direction calculating means for calculating a normal direction at a point, and the optical axis of the imaging optical means based on the calculation result of the normal direction calculating means so that the optical axis of the imaging optical means coincides with the normal direction on the surface to be read. An image reading apparatus comprising: an image forming optical unit; and a direction adjusting unit that adjusts a direction of the image pickup unit with respect to the surface to be read.