JP2019176396A - Image reading apparatus - Google Patents

Abstract

To provide an image reading apparatus capable of obtaining auxiliary signals even in an imaging optical system in which many small-sized imaging lenses are arranged.SOLUTION: An image reading apparatus 101 according to the present invention includes: a light source 12 for imaging which illuminates a reading object 1 with illumination light; a plurality of sensor chips 25 which have a lens 18 and a lens 20 respectively and read each of a plurality of imaging optical elements 15 and images formed by the plurality of imaging optical elements 15; and a light source 40 for ranging which irradiates the reading object 1 with auxiliary signal light directed to the lens 18 from the lens 20 of a target imaging optical element which is the imaging optical element 15 to be subjected among the plurality of imaging optical elements 15. The light source 40 for ranging is disposed so that the auxiliary signal light is read by the sensor chips 25 reading the image of the adjacent imaging optical element adjacent to the target imaging optical element.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image reading apparatus that reads an image of a reading object.

  In an image reading apparatus used for a copying machine, a bill reader, a scanner, a facsimile, and the like, a plurality of sets of imaging lenses and line image sensors are arranged in the main scanning direction.

  The imaging lens of the image reading device collects the light scattered by the reading object moved in the sub-scanning direction, and forms an image of the collected light on the imaging surface of the line image sensor. An image of the reading object is formed on the imaging surface.

  In a general image reading apparatus, a plurality of imaging lenses arranged in the main scanning direction have a part of a visual field range, which is a range for collecting light scattered by a reading object, arranged next to the imaging lens. In many cases, they are arranged so as to overlap a part of the field of view of the imaging lens. In this case, when synthesizing the images read by the plurality of line image sensors, it is necessary to acquire overlapping information such as the width of the overlapping portion of the visual field range.

  As a method for acquiring the overlapping information described above, for example, there is disclosed a method in which a marker arranged at the overlapping position is provided and a marker irradiation light source for irradiating the marker is provided between two adjacent imaging lenses. (For example, refer to Patent Document 1). Here, first, the auxiliary signal for image combination is generated by reading the light of the marker irradiation light source reflected by the marker with the line image sensor. Next, the duplication information is estimated by comparing the two auxiliary signals generated by the line image sensors adjacent to each other.

  For the purpose of reducing the size of the entire imaging optical system, an image reading apparatus using an imaging optical system in which a large number of small imaging lenses are arranged is disclosed (for example, see Patent Document 2).

JP 2009-171003 A International Publication No. 2017/195487

  Generally, the width of the reading range of each imaging lens is larger than the width dimension of the imaging lens. However, if each imaging lens is miniaturized as in Patent Document 2, the reading range of each imaging lens is reduced. It is known that the width approaches the width dimension of the imaging lens.

  In the configuration as in Patent Document 2, since the space in the width direction between the imaging lenses becomes narrow, it is impossible to provide a space for arranging the marker generating light source as in Patent Document 1. In this case, there is a problem that the auxiliary signal cannot be obtained and the image composition processing cannot be performed appropriately.

  The present invention has been made in view of the circumstances as described above, and is to obtain an image reading apparatus capable of obtaining the auxiliary signal even in an imaging optical system in which a large number of small imaging lenses are arranged. Objective.

  An image reading apparatus according to the present invention forms an image of a light source for imaging that illuminates a reading object with illumination light, a condensing unit that collects illumination light scattered by the reading object, and the collected illumination light. A plurality of image forming optical elements arranged in the main scanning direction, and a plurality of images formed by the plurality of image forming optical elements, respectively. A sensor chip, and an auxiliary light source for irradiating the reading object with auxiliary signal light directed from the imaging unit of the target imaging optical element, which is the target imaging optical element among the plurality of imaging optical elements, to the condensing unit The auxiliary light source is arranged such that a sensor chip that reads an image of an adjacent imaging optical element adjacent to the target imaging optical element reads auxiliary signal light.

  In the image reading apparatus according to the present invention, an auxiliary signal for image combination can be obtained even in an imaging optical system in which a large number of small imaging lenses are arranged.

FIG. 2 is a schematic cross-sectional view in the sub-scanning direction (Y direction) of the image reading apparatus according to Embodiment 1 of the present invention. 1 is a cross-sectional view showing an image reading apparatus according to Embodiment 1 of the present invention. 1 is a perspective view showing an image reading apparatus according to Embodiment 1 of the present invention. It is a schematic diagram which shows the relationship between the imaging reading range of several imaging optical elements, and an imaging reading range. It is explanatory drawing for demonstrating concretely the sensor chip of Embodiment 1 of this invention. It is the schematic regarding the relationship of the imaging position by the imaging optical element located mutually adjacent. It is a flowchart for demonstrating operation | movement of the image process part which concerns on Embodiment 1 of this invention. It is a flowchart explaining the calculation process of the floating amount z of step 3 in FIG. It is explanatory drawing for demonstrating an image restoration process in detail. It is a timing chart for demonstrating operation | movement of the electronic shutter which concerns on Embodiment 2 of this invention. It is a figure which shows the image reading apparatus which concerns on Embodiment 3 of this invention. It is a figure showing the timing chart which the light source for imaging and the light source for distance measurement which concern on Embodiment 3 of this invention light. It is a figure showing the timing chart which the light source for ranging concerning the Embodiment 4 of this invention lights. It is a figure showing an example of the timing chart which the light source for ranging concerning the Embodiment 5 of this invention lights. It is a figure showing another example of the timing chart which the light source for ranging concerning the Embodiment 5 of this invention lights.

Embodiment 1 FIG.
The contact image sensor according to the first embodiment of the present invention is a device that reads an image of an object to be read as a reading object. For example, a facsimile, a copier, a scanner, a multifunction peripheral, a financial terminal, an industrial inspection device Etc. The reading object is, for example, a manuscript, a mark sheet, a banknote, a check or other securities.
In the following drawings, the X direction, the Y direction, and the Z direction are described as indicating the main scanning direction, the sub scanning direction, and the height direction, respectively.

  FIG. 1 is a schematic cross-sectional view in the sub-scanning direction (Y direction) of the image reading apparatus 101 according to Embodiment 1 of the present invention. 2 is a sectional view showing the image reading apparatus 101, and FIG. 3 is a perspective view showing the image reading apparatus 101 according to Embodiment 1 of the present invention. 2 and 3, the housing 10 is not shown for convenience of illustration. In FIGS. 1 and 3, the configurations of the holders 23 and 24 and the like are omitted.

1 to 3, the reading object 1 is placed on the top glass 11 of the image reading apparatus. In the scanner device, in order to scan a paper document or the like which is the reading object 1, the reading object 1 is moved on the top glass 11 in the sub-scanning direction which is the Y direction in the drawing.
In the office copying machine, the entire structure other than the top plate glass 11 shown in FIG. 2 is moved in the sub-scanning direction, which is the Y direction in the drawing, with respect to the reading object 1 placed on the top plate glass 11. The The moving direction can be either a + Y direction (positive Y direction) or a -Y direction (negative Y direction).

  The image reading apparatus 101 corresponds to a housing 10, an imaging light source 12, an imaging system array 14, a holder 23, a holder 24, a plurality of sensor chips 25 a to 25 d, and a plurality of ranging light sources (an “auxiliary light source”). ) 40a to 40d, and an image processing unit 28.

Hereinafter, the imaging optical elements 15a to 15d, the sensor chips 25a to 25d, and the ranging light sources 40a to 40d are collectively referred to as “imaging optical element 15”, “sensor chip 25”, and “measurement”, respectively. It may be simply referred to as “distance light source 40”.
Although illustration and description are omitted, the imaging optical element 15, the sensor chip 25, and the distance measuring light source 40 are actually placed on the right side of the imaging optical element 15d (lens 18d, diaphragm 19, lens 20d). Are arranged.

  The housing 10 illustrated in FIG. 1 stores or holds each component of the image reading apparatus 101 therein.

The imaging light source 12 illuminates the reading object 1 with illumination light 13. The illumination light 13 from the imaging light source 12 becomes illumination light 16 scattered by the reading object 1 by illuminating the reading object 1. More specifically, the imaging light source 12 is a light source that extends in the main scanning direction, which is the X direction in the drawing, and illuminates the reading object 1 with illumination light 13 (illustrated by a dotted arrow in FIG. 1).
The imaging light source 12 includes, for example, an LED (Light Emitting Diode) as a light source and a light guide such as a resin for converting the light emitted from the LED into the illumination light 13 of the reading object 1. Can do. This light guide is a cylindrical light guide that extends in the main scanning direction. The illumination light 13 is, for example, white light including components such as red, green, and blue, but is not limited thereto.

  The imaging system array 14 has a plurality of imaging optical elements 15a to 15d (may be collectively referred to as “imaging optical element 15”), and is arranged in the main scanning direction (X direction). The

  More specifically, the plurality of imaging optical elements 15a to 15d... Are arranged in one direction (in the figure, the X direction (main scanning direction)). The configuration of the imaging system array 14 in FIGS. 2 and 3 is merely an example, and the imaging system array 14 only needs to have a plurality (two or more) of imaging optical elements 15.

The plurality of imaging optical elements 15 form a condensing unit (corresponding to “lens 18” described later) for condensing the illumination light 16 scattered by the reading object 1 and the condensed illumination light 16 is imaged. And an image forming unit (corresponding to “lens 20” described later) for forming an image of the reading object 1.
More specifically, the imaging optical element 15 includes a lens 18, a diaphragm 19, and a lens 20. The lens 18 collects the illumination light 16 scattered by the reading object 1.
The diaphragm 19 is an optical component that blocks a part of the light 17 collected by the lens 18. The lens 20 forms an image on the image plane 22 with the light 21 that has passed through the diaphragm 19.
In FIG. 2 and FIG. 3, the imaging optical element 15 is composed of a pair of lenses (lens 18 and 20). For example, the imaging optical element 15 is a lens 18 or a lens 20. You may be comprised with the lens and you may be comprised with three or more lenses.

The two holders 23 and 24 hold the plurality of imaging optical elements 15 (imaging system array 14) inside the housing 10 illustrated in FIG.
Specifically, the holder 23 holds the lens 18 included in the plurality of imaging optical elements 15. The holder 24 holds the lens 20 included in the plurality of imaging optical elements 15.

The plurality of (for example, four or more) sensor chips 25a to 25d... Read each of the images formed by the plurality (for example, four or more) of imaging optical elements 15a to 15d.
More specifically, as shown in FIGS. 2 and 3, the plurality of sensor chips 25 a to 25 d... Read images in the imaging reading ranges 31 a to 31 d... Generated by the imaging optical elements 15 a to 15 d. For example, the sensor chip 25a reads an image in the imaging reading range 31a generated by the imaging optical element 15a.

The plurality of distance measuring light sources 40a to 40d are arranged for the plurality of imaging optical elements 15a to 15d, respectively. Hereinafter, the imaging optical element 15 arranged with the distance measuring light source 40 as a target may be referred to as a “target imaging optical element 15”.
The plurality of ranging light sources 40a to 40d... Are opposite to the reading object 1 with respect to the respective lenses 20 (imaging units) of the plurality of target imaging optical elements 15a to 15d. ) On the side closer to the sensor substrate 29 than the object to be read.

The distance measuring light sources 40a to 40d... Are distance measuring signal lights (FIGS. 2 and 3) directed from the lens 20 (image forming section) of the target image forming optical elements 15a to 15d. (Corresponding to a broken line portion) is applied to the reading object 1 through the object imaging optical elements 15a to 15d.
In FIG. 3, the areas irradiated with the reading object 1 by the distance measuring light sources 40 a to 40 d are irradiation areas 41 a to 41 d. Hereinafter, the irradiation areas 41a to 41d... May be collectively referred to as “irradiation area 41”.

  Since the above description is made assuming that the imaging optical element 15 (not shown) is arranged on the right side of the imaging optical element 15d in the drawing, the distance measuring light source 40d is used as the imaging optical element 15d. It is arranged. However, when the imaging optical element 15 is not disposed on the right side of the target imaging optical element 15d, the distance measuring light source 40d may be omitted.

  Further, the distance measuring light source 40 is arranged so that the sensor chip 25 that reads the image of the imaging optical element 15 adjacent to the target imaging optical element 15 reads the distance measuring signal light via the adjacent imaging optical element 15. Is done. The ranging signal light may be hereinafter referred to as “auxiliary signal light”.

The distance measuring light source 40b will be described as an example. In FIG. 3, the distance measuring signal light emitted from the distance measuring light source 40b is transmitted from the lens 20 (image forming section) of the image forming optical element 15b to the lens 18 (collected light). The irradiation area 41b on the reading object 1 is irradiated toward the optical part). The distance measuring signal light irradiated to the irradiation area 41b reaches the sensor chip 25c via the imaging optical element 15c adjacent to the distance measuring light source 40b. The sensor chip 25c generates a distance measurement signal by reading the distance measurement signal light.
Although the details of this distance measurement signal will be described later, this distance measurement signal is used for deriving image restoration information such as the amount of floating z of the reading object with respect to the top glass 11, and an image restoration process to be described later using this image restoration information. I do. Here, the floating amount z is the distance between the top glass 11 and the reading object 1 in the height direction. Although details will be described later, the image restoration information includes, in addition to the floating amount z, the width of the overlapping imaging range, the reduction magnification of the image data, and the like.

  The distance measuring light source 40 is preferably constituted by a bare chip type LED having no package. When configured as described above, the LED can be mounted using the wiring pattern formed on the sensor substrate 29, and the LED is directly mounted on the sensor substrate 29 without preparing a separate LED mounting substrate. be able to.

As described above, the distance measuring light source 40 is disposed on the opposite side from the reading object 1 with respect to the target imaging optical element 15, and even when the space between the imaging optical elements 15 described above is small. The distance measuring signal as an auxiliary signal for image combination can be obtained.
In the drawing, a configuration in which a plurality of distance measuring light sources 40a to 40d are provided is shown. However, the distance measuring light source 40 has at least one image forming optical element 15 among the plurality of image forming optical elements 15a to 15d. As long as it is provided. Further, a configuration may be adopted in which a plurality of ranging light sources 40 are arranged corresponding to each imaging optical element 15.

  The image processing unit 28 uses a ranging signal (hereinafter, referred to as “auxiliary data”) generated by the sensor chips 25a to 25d. Image restoration processing is performed on the plurality of image data generated by ˜25d. More specifically, the image processing unit 28 performs an image restoration process, which will be described later, based on the distance measurement signal, and superimposes a plurality of image data (reduced transfer images).

  4 shows imaging reading ranges 31a to 31d of the plurality of imaging optical elements 15 (corresponding to diagonal stripes in the drawing), overlapping imaging ranges 32a to 32c (corresponding to double-headed arrows in the drawing), And image reading ranges 33a to 33d (corresponding to portions surrounded by broken lines in the figure). In the drawing, for convenience of explanation, the imaging reading ranges 31a to 31d are shown in two upper and lower stages, but in reality, the imaging reading ranges 31a to 31d are arranged while being overlapped on a straight line.

  FIG. 5 is an explanatory diagram for specifically explaining the sensor chips 25 a to 25 d... And the distance measuring light sources 40 a to 40 d of the first embodiment of the present invention. The figure (2) shows the enlarged view of a set of ranging light source 40 and sensor chip 25 from the figure (1).

As shown in FIGS. 5A and 5B, each sensor chip 25 is a line chip having a plurality of image pickup elements 250 arranged on the sensor substrate 29 and arranged in the X direction.
The sensor chip 25 according to the present embodiment includes an image sensor that reads an image of a reading object and a distance measurement sensor that reads distance measurement signal light.
In the figure, assuming that the image sensor 250 of the sensor chip 25 is from the first column to the fourth column from the top, when reading a color image, as shown in FIG. The image sensor 250 is composed of a total of three rows and three rows. The image sensor 250 in the first column reads red light (R), the image sensor 250 in the second column reads green light (G), and the image sensor 250 in the third column reads blue light (B). On the other hand, the distance measuring sensor (fourth row) is an image sensor 250 that reads infrared light (IR).

  The distance measuring light source 40 can be constituted by, for example, an LED that emits near-infrared light. The ranging signal light (IR) emitted from the ranging light source 40 is read by the fourth row of the sensor chip 25.

  Here, before describing the arrangement of the sensor chip 25 and the distance measuring light source 40 in more detail, the optical ranges related to the imaging optical element 15 and the sensor chip 25 will be defined with reference to FIGS.

The imaging reading ranges 31a to 31d (hereinafter sometimes collectively referred to as “imaging reading range 31”) are the sensor chips 25a to 25d... Corresponding to the imaging optical elements 15a to 15d. This is the range of the reading object 1 that can be imaged on the reading surface.
In the overlapping imaging ranges 32a to 32c (hereinafter sometimes collectively referred to as “overlapping imaging range 32”), the imaging reading ranges 31 of the plurality of imaging reading ranges 31a to 31d overlap. It is a range. As an example, the overlapping imaging range 32a is an overlapping portion of the imaging reading ranges 31a and 31b, and the overlapping imaging range 32b is an overlapping portion of the imaging reading ranges 31b and 31c. That is, it is a range where a part of two adjacent imaging reading ranges 31 among a plurality of imaging reading ranges 31 overlap.

The imaging reading ranges 33a to 33d (sometimes collectively referred to as “imaging reading range 33”) means that each imaging optical element 15 forms an optical image on the imaging surface 22. This is a range on the reading object 1 to be read.
The imaging reading range 33 of the imaging optical element 15 is formed wider than the imaging reading range 31 of the imaging optical element 15 so that a missing image is not generated on the sensor chip 25.
The imaging field ranges 34a to 34d (hereinafter sometimes collectively referred to as “imaging field range 34”) are imaging surfaces on which the imaging reading range 33 is transferred by the imaging optical element 15. It is the range on 22.

Here, the arrangement of the sensor chip 25 and the distance measuring light source 40 will be described in detail.
As shown in FIG. 5 (1), the distance measuring light source 40 has its light emitting surface disposed within the imaging field range 34 of the imaging surface 22. The distance measuring light source 40 is mounted on the sensor substrate 29 such that the light emitting surface thereof is separated from the sensor chip 25 in the X direction and overlapped in the Y direction.
By arranging as described above, there is an effect that the ranging light source 40 can easily irradiate the imaging reading range 31 of the adjacent sensor chip 25.

Here, the operation of the ranging signal light emitted by the ranging light source 40b will be described in detail with reference to FIG. FIG. 6 is a schematic diagram regarding the relationship between the imaging positions of the imaging optical elements 15b and 15c located adjacent to each other.
It is assumed that the reading object 1 is separated from the top glass 11 by the floating amount z, and the reduction magnification from the reading object 1 to the image plane 22 is M (z). The optical axes of the imaging optical elements 15b and 15c are the optical axis 35b and the optical axis 35c, respectively. The imaging optical elements 15b and 15c are assumed to be separated by a pitch P.
The ranging light source 40b irradiates the target imaging optical element 15b arranged corresponding to the ranging light source 40b with incident light from the light emitting point P1. The target imaging optical element 15b irradiated with the incident light irradiates the reading object 1 with the emitted light, and the imaging optical element 15c (hereinafter referred to as “hereinafter referred to as“ imaging optical element 15c ”) disposed adjacent to the target imaging optical element 15b. An image is formed at a point P2 on the imaging reading range 31c.
More specifically, when the distance measuring light source 40b is turned on, the emitted light is collected by the lens 20b of the target imaging optical element 15b, and passes through the stop 19b of the target imaging optical element 15b among the condensed light. The collected light is condensed on the reading object 1 by the lens 18b of the object imaging optical element 15b. Since the imaging surface 22 and the reading object 1 are in a conjugate relationship, the light beam emitted from the light emitting point P1 on the distance measuring light source 40b forms an image on the point P2 on the reading object 1. Further, an image of the light emitting surface of the distance measuring light source 40 b is formed in the irradiation area 41 b on the reading target 1.

  Since the distance measuring light source 40b is spaced apart from the sensor chip 25b in the X direction, the irradiation area 41b where the image of the light emitting surface of the distance measuring light source 40b is formed is outside the imaging reading range 31b. It is formed within the imaging reading range 31c of the imaging optical element 15c adjacent to the imaging optical element 15b. Since the light beam that forms the image of the light emitting surface in the irradiation area 41b is reflected and scattered by the reading object 1, it is condensed on the imaging surface 22 by the imaging optical element 15c adjacent to the imaging optical element 15b. . Since the imaging surface 22 and the reading object 1 are in a conjugate relationship, the point P2 on the reading object 1 forms an image with the light receiving point P3 on the imaging surface 22.

  As described above, the image of the light emitting surface formed in the irradiation region 41b by the target imaging optical element 15b is within the imaging reading range 31c of the adjacent imaging optical element 15c adjacent to the target imaging optical element 15b. Therefore, the light receiving point P3 is on the sensor chip 25c corresponding to the adjacent imaging optical element 15c. Further, the image of the light emitting surface formed in the irradiation area 41 b of the reading object 1 is further transferred by the adjacent imaging optical element 15 c, and an image of the light emitting surface is formed in the transfer area 42 b on the image forming surface 22. .

  In the above description, the entire range of the light emitting surface of the distance measuring light source 40b has been described as being within the range of the image forming field range 34b. 34b may be included.

  Although the case where the light emitting surface of the ranging light source 40 is arranged on the imaging surface 22 is taken as an example, at least a part of the irradiation region 41 irradiated with the ranging signal light is adjacent to the target imaging optical element 15. As long as the distance measuring light source 40 is disposed so as to be included in the imaging reading range 31 of the adjacent imaging optical element 15, other than the above-described arrangement may be used.

Here, in order to describe the spatial arrangement of the distance measuring light source 40, an imaging field space and an imaging field space are defined below.
In the imaging field space, when the light scattered in each imaging reading range 33 is condensed and imaged, the light beam emitted from the lens 20 (imaging part) of each imaging optical element 15 passes. It is a possible space.
In the imaging field space, when the light scattered in each imaging reading range 31 is condensed and imaged, the light beam emitted from the lens 20 (imaging part) of each imaging optical element 15 can pass therethrough. Space.

  In the above description, the case where the light emitting surface of the distance measuring light source 40 is arranged on the imaging surface 22 has been described, but the present invention is not limited to the above arrangement. In the distance measuring light source 40, at least a part of the light emitting surface of the distance measuring light source 40 is outside the main scanning direction of the imaging visual field space of the target imaging optical element 15 (that is, in the main scanning direction with respect to the imaging visual field space). It is only necessary to be provided within the imaging field space.

Further, the distance measuring light source 40 may be arranged in the above-described space as follows. The cut surface when the imaging visual field space is cut along a plane parallel to the reading object 1 (or the reading surface of the sensor chip 25) is separated from the cut surface in the X direction on the plane including the cut surface. And it may be arrange | positioned so that it may overlap with the Y direction with respect to the said cut surface.
By arranging as described above, the ranging signal light of the ranging light source 40 is reliably read by the sensor chip 25 corresponding to the adjacent imaging optical element 15.

  Next, the operation of the image processing unit 28 will be described with reference to FIG. FIG. 7 is a flowchart for explaining the operation of the image processing unit 28 according to the present embodiment.

  First, the image processing unit 28 acquires image data generated by the sensor chip 25 (step S1).

Specifically, the first to third columns of the sensor chip 25 read reduced transfer images corresponding to the three colors of RGB formed by the imaging optical element 15. The fourth column of the sensor chip 25 reads infrared light (IR) and is used as a sensor for measuring the floating amount z of the reading object 1 with respect to the top glass 11 as described later. The image data generated by the sensor chip 25 is output to the image processing unit 28.
The number of columns of the sensor chip 25 described above is an example, and the number of columns may be changed as appropriate. Although described in detail in an embodiment described later, depending on the control method of the imaging light source 12 and the distance measuring light source 40 and the control method of the sensor chip 25, the image sensor and the distance measuring sensor are read by a common sensor. You may do it.

  The image processing unit 28 acquires a ranging signal (auxiliary data) generated by the sensor chip 25 (step S2). For convenience of explanation, step S1 and step S2 are described separately, but in the present embodiment, step S1 and step S2 may be executed simultaneously.

Specifically, since the ranging light source 40b emits infrared light, it is not captured (read) by the first to third columns (RGB) of the sensor chip 25c, but is captured by the fourth column. An image of the light emitting surface of the distance measuring light source 40b is transferred to the transfer region 42b of the sensor chip 25c and is captured by the fourth row of the sensor chip 25c.
With the above configuration, light from the distance measuring light source 40 is not captured as noise by the image sensor, and good image data can be acquired by the image sensor.

  Subsequently, the image processing unit 28 performs a calculation process on the floating amount z of the reading object 1 with respect to the top glass 11 using the distance measurement signal (step S3).

  The image processing unit 28 performs image restoration processing (details will be described later) on a plurality of image data using the last calculated floating amount z (step S4).

  Here, step S3 in FIG. 7 will be described in detail with reference to FIGS. FIG. 8 is a flowchart for explaining the operation of step S3 in detail.

  First, the image processing unit 28 reads an initial setting value from a storage unit (not shown) (step S31).

This initial set value includes position information (information regarding the imaging optical element 15, the imaging optical element 15, the sensor chip 25, and the distance measuring light source 40). The position information is, for example, the pitch P in the X direction of the imaging optical element 15, the width Xs in the X direction of the sensor chip 25, and the position ΔX0 of the distance measuring light source 40 (hereinafter referred to as “light source position ΔX0”). Yes.)
Here, as shown in FIG. 6, the light source position ΔX0 is a distance in the main scanning direction between the optical axis 35b of the target imaging optical element 15b and the light emission point P1 of the distance measuring light source 40b.

Subsequently, the image processing unit 28 calculates a light receiving position ΔX2 that is the position of the imaging element 250 that has received the ranging signal light among the plurality of imaging elements 250 based on the ranging signal (step S32).
The light receiving position ΔX2 is a distance in the main scanning direction between the optical axis 35c of the adjacent imaging optical element 15c and the light receiving point P3 of the sensor chip 25 as shown in FIG. More specifically, the image processing unit 28 uses the image sensor 250 positioned on the optical axis 35c of the adjacent imaging optical element 15c as a reference, and calculates the number of pixels from the reference to the image sensor 250 that has received the distance measurement signal. Calculated as the light receiving position ΔX2.

Finally, the image processing unit 28 estimates the floating amount z of the reading object 1 with respect to the top glass 11 on which the reading object 1 is arranged, using the light receiving position ΔX2 and the light source position ΔX0 (step S33).
In FIG. 6, a light beam emitted from a light emitting point P1 that is separated from the optical axis 35b by ΔX0 to the left forms an image at a point P2 on the reading object 1. The point P2 is separated from the optical axis 35b by ΔX1, is separated from the optical axis 35c of the imaging optical element 15c by ΔX1 ′, and the reduction ratio when the floating amount is z is M (z). ) And equation (2).
ΔX1 = ΔX0 / M (z) (1)
ΔX1 ′ = P−ΔX1 (2)

Since the image forming point P3 by the image forming optical element 15c at the point P2 is separated from the light receiving position ΔX2 from the optical axis 35c, Expression (3) is established.
ΔX2 = M (z) · ΔX1 ′ (3)

Furthermore, Expression (4) is established from Expressions (1) to (3).
ΔX2 = M (z) · P−ΔX0 (4)

Here, the imaging reading range Xf (z) is assumed to be a function of the floating amount z calculated in advance. For example, the imaging reading range Xf (z) can be expressed as a linear function (xf + α · z). Here, xf is an imaging reading range Xf (z = 0) when the floating amount z is 0, and α is a proportionality constant.
Hereinafter, the imaging reading range Xf (z) will be described using the linear function, but it goes without saying that the imaging reading range Xf (z) is not limited to this function. The imaging reading range Xf (z = 0) and the proportionality constant α are assumed to have been acquired in step S31 as initial setting values.

Using the position information and the linear function (imaging reading range Xf (z)), the reduction magnification M (z) when the floating amount is z is expressed by Expression (5).
M (z) = Xs / Xf (z) = Xs / (xf + α · z) (5)

When Expression (5) is substituted into Expression (4), Expression (6) is established. Expression (6) represents the relationship between the floating amount z and the light receiving position ΔX2.
ΔX2 = P · Xs / Xf (z) −ΔX0
= P · Xs / (xf + α · z) −ΔX0 (6)

By transforming equation (6), equation (7) can be derived. Since values other than the light receiving position ΔX2 are acquired as initial setting values on the right side of Expression (7), if the light receiving position ΔX2 can be obtained, the floating amount z can be calculated by Expression (7).
z = (P · Xs) / (α · ΔX0 + α · ΔX2) −xf / α (7)

  In the above description, the floating amount z is calculated using the above-described initial setting value. However, generally, the magnitude of the light receiving position ΔX2 with respect to the light source position ΔX0 changes according to the floating amount z. It has been known. Therefore, a relational expression between the light source position ΔX0 and the light receiving position ΔX2 and the floating amount z may be derived in advance, and the floating amount z may be calculated using this relational expression.

FIG. 9 is an explanatory diagram for explaining the image restoration processing in detail. The case where the document image 50 of the reading object 1 is read by three sensor chips 25a to 25c and three output image data 51a to 51c are generated is illustrated. The image restoration process in the image processing unit 28 includes (a) image combination position calculation process, (b) image scaling process, and (c) image combination process.
In FIG. 9, FIG. 9A is an example of a document image 50 of the reading object 1. FIG. 2B shows an example in which the output image data 51a to 51c are arranged when the document image 50 is placed on the top glass 11, that is, when the floating amount z is zero. FIG. 3C is a view showing the image reading ranges 31a to 31c and the overlapping image pickup ranges 32a to 32b of FIG. FIG. 4 (4) shows output image data 51a to 51c when the floating amount z is larger than zero. FIG. 5 (5) is a view showing the image reading ranges 31a to 31c and the overlapping image pickup ranges 32a to 32b of FIG.

(A) Image combined position calculation process When the above-mentioned initial setting value is used, the width XOL (z) of the overlapping imaging range 32 when the floating amount is z is expressed by Expression (8).
XOL (z) = Xf (z) −P = (xf + α · z) −P (8)
In the image combination position calculation process, the width XOL of the overlapping imaging range 32 between the adjacent imaging reading ranges 31 is calculated by substituting the floating amount z into the equation (8). For example, in FIG. 2 (2), images are overlapped at the boundary between the output image data 51a and the output image data 51b. By calculating the width XOL of the overlapped imaging range 32, ) Image combining processing can be performed appropriately.

(A) Image scaling processing In the image scaling processing, the reduction ratio M (z) is calculated by substituting the floating amount z into the formula (1), and output image data is calculated using the reduction ratio M (z). 51a to 51c are adjusted to dimensions (main scanning direction) corresponding to the document image 50.
For example, the width in the X direction of the imaging reading ranges 31a, 31b, and 31c in FIG. 9 (5) is larger than that in FIG. 9 (3), and the output image data 51a, 51b, and 51c in FIG. It can be seen that the image is reduced in the X direction as compared with that of FIG. Even for such an output image reduced in the X direction, the image size can be appropriately adjusted by performing the above-described image scaling process.

(C) Image Combining Process The image processing unit 28 uses the overlapped imaging range of the image restored by the above-described process (a) based on the width XOL (z) of the overlapping imaging range 32 in each adjacent boundary range. This is a process for creating an image superimposed by 32 widths XOL.

In step S <b> 3, when the image processing unit 28 determines the floating amount z for each of the two adjacent imaging reading ranges 31 out of the plurality of imaging reading ranges 31, for each of the two adjacent imaging reading ranges 31. The above processes (a) to (c) may be performed.
With the above-described configuration, the floating amount z may vary depending on the position in the X direction. However, since an appropriate floating amount z can be acquired in each of the two adjacent imaging reading ranges 31, an image with little deterioration can be obtained. Can do.

  Here, (a) calculating the image coupling position using a light source that directly irradiates light to the overlapping imaging range 32 without using the distance measuring light source 40 that irradiates the reading object 1 via the imaging optical element 15. The case of processing is considered as a comparative example.

  The comparative example performs the following processing. First, with respect to the output image 51a shown in FIG. 9, the output image 51b is shifted in the (−X) direction, and the sum of absolute differences between the two images is obtained. When the value of the sum of absolute differences is small, it can be determined that the similarity between the two images is high. By obtaining the shift amount X that minimizes the sum of absolute differences, the width XOL in the X direction of the overlapping imaging range 32 is obtained, and image combination position calculation processing is performed.

  As a result of the inventor's diligent study, in (a) image combination position calculation processing of such a comparative example, depending on the pattern of the reading object 1, the images are not properly superimposed, and deteriorated restored image I discovered that there are cases where I can only get it.

  Examples of the reading object 1 in which the images are hardly overlapped appropriately include, for example, a blank image having no image information in the overlapping imaging range 32, and a pattern image repeatedly appearing in the X direction.

As an example of a blank area without image information, there is a portion where the output image 51b and the output image 51c in FIG. 9B overlap. In this portion, as shown in the overlapping imaging range 32b in FIG. 9 (3), the portion corresponding to the character only with the background color is not included.
At this time, even if the above (a) image combining process is performed, the sum of absolute differences of the two images is a constant value regardless of the shift amount of the image, and the width XOL of the overlapping imaging range 32 cannot be calculated. Similarly, the floating amount z cannot be calculated.

  As an example of a pattern image that repeatedly appears in the X direction, there is a linear lattice pattern arranged with a fine pitch p in the X direction. At this time, the sum of absolute differences between the two images takes a minimum value for each pitch p, and it is impossible to determine which minimum value takes the shift amount corresponding to the width XOL of the true overlapping imaging range 32.

On the other hand, in the (a) image combination position calculation processing according to the present application, even when the above-described image combination is difficult (such as when the image in the overlapping imaging range 32 is a blank image or the pattern image), the ranging light source 40 The floating amount z can be estimated using the distance measuring signal light according to.
Furthermore, the image combination position calculation process and the image scaling process can be performed without error, and a good image without an image combination error can be obtained.

  Further, since the ranging light source 40 can be directly mounted on the sensor substrate 29, it is not necessary to prepare a separate light source substrate, and the number of components can be reduced and the mounting can be performed in a compact manner.

Embodiment 2. FIG.
The image reading apparatus according to the second embodiment is different from the first embodiment in that the sensor chip further includes a shutter (not shown) having a light blocking function for blocking light.
Further, in the sensor chip 25 having the image sensor and the distance measuring sensor, the electronic shutter (first shutter) of the image sensor opens and closes at a timing different from that of the distance measuring sensor shutter (second shutter). This point of control is also different from the first embodiment.
The following description will be made by taking an electronic shutter that adjusts the exposure time by electronically controlling as the shutter, but a physical shutter that opens and closes a light shielding mechanism that physically shields light may be used. An image formed on the sensor chip 25 by the imaging optical element 15 may be referred to as image signal light for convenience.

FIG. 10 is a timing chart for explaining the operation of the electronic shutter, and FIGS. 10A and 10B are timing charts of the image electronic shutter and the distance measuring electronic shutter, respectively. In the figure, the horizontal axis and the vertical axis indicate time and the open / close state of the shutter.
The sensor chip 25 outputs four columns of photoelectrically converted signals to the image processing unit 28 every time t. Here, only the light incident on the sensor chip 25 when the electronic shutter is OPEN (open state) is read by the sensor chip 25 as a signal. On the other hand, the light incident when the electronic shutter is CLOSE (closed state) is not read by the sensor chip 25 as a signal.

As shown in FIG. 10, in each reading cycle t in the sensor chip 25, the electronic shutter for image and distance measurement are not simultaneously opened, that is, the reading time of the image signal light and the reading time of the auxiliary signal light are different. The opening and closing of the electronic shutter is controlled so as not to overlap.
Further, both light sources are controlled so that the imaging light source 12 and the distance measuring light source 40 are turned on in synchronization with the opening and closing of the electronic shutter. That is, only the imaging light source 12 is lit when the image electronic shutter is OPEN, and only the distance measuring light source 40 is lit when the distance electronic shutter is OPEN.

  The sensor chip 25 can suppress the ranging signal from being superimposed as noise on the image signal by reading the image signal light and the ranging signal light separately in time.

In the drawing, of the reading cycle t of the sensor chip 25, the reading time of the image signal light is 0.8 t, and the reading time of the distance measuring signal light is 0.2 t.
As described above, by configuring the image signal light reading time to be longer than the distance measurement signal light reading time, it is possible to acquire image data while suppressing a decrease in the image signal light reading time. Therefore, it is possible to suppress the deterioration of the SN ratio (signal to noise ratio) of the image data.
The ratio of the distance measurement signal reading time to the image signal reading time is not limited to the above example, and may be changed as appropriate.

  As described above, in the present embodiment, since the image signal and the distance measurement signal are acquired separately in time, light other than infrared light may be used as the distance measurement light source 40. . As the filter in the fourth row of the sensor chip 25, a filter that transmits light in accordance with the wavelength of the distance measuring light source 40 may be used.

In the first embodiment, the first to third color filters on the sensor chip 25 are filters that transmit only one of R, G, and B. If a simple color filter is used as each filter, the color filter has a slight transmittance in the IR wavelength band, so that the distance measurement signal may be superimposed on the image signal as noise.
In the present embodiment, even when the above-described simple color filter is used, it is possible to suppress the ranging signal from being superimposed on the image signal as noise.

  Furthermore, since both the image signal light and the distance measuring signal light are read in each reading cycle t of the sensor chip 25, when both signals are read in different reading cycles (in the case of Embodiment 3 described later). In comparison, in addition to the above-described effects, the reading cycle t can be set longer.

Embodiment 3 FIG.
FIG. 11 is a diagram showing a sensor substrate 29A of the image reading apparatus according to the third embodiment of the present invention. FIG. 12 shows that the imaging light source 12 and the distance measuring light source 40 according to the third embodiment of the present invention are turned on. It is a figure showing a timing chart.
In the present embodiment, the point that the imaging light source 12 and the distance measuring light source 40 are controlled to be lit at different times and that the distance measuring sensor and the image sensor are shared are described above. Different from the embodiment. As shown in FIGS. 5 (2) and 11 (2), the sensor chip 25A has a configuration in which the fourth row, which is a distance measuring sensor in the sensor chip 25, is omitted.
Imaging illumination light emitted from the imaging light source 12 is white light, and may be referred to as light from the ranging light source 40 emitted from the ranging light source 40 (hereinafter referred to as “ranging illumination light”). .) Is, for example, red. In the present embodiment, the distance measuring illumination light is not necessarily red, and may be blue, green, or white.

As shown in FIG. 12, the illumination light is switched over time. To simplify the notation, the time t0 to t1 is a period K1, the time t1 to t2 is a period K2, the time t2 to t3 is a period K3,. In FIG. 12, the ranging light source 40 and the imaging light source 12 are alternately lit, and the ranging light source 40 is lit in the odd-numbered periods (K1, K3, K5...) And the even-numbered periods (K2). , K4, K6...), The imaging light source 12 is turned on.
That is, control is performed so that the distance measuring light source 40 is turned on and the imaging light source 12 is turned off in synchronization with the reading time of the distance measuring signal light by the sensor chip 25.
Control is performed so that the imaging light source 12 is turned on and the distance measuring light source 40 is turned off in synchronization with the reading time of the image signal light by the sensor chip 25.

The sensor chip 25A reads line data for three columns in each period K1, K2,. Note that the lengths of the odd-numbered period and the even-numbered period may be the same or different.
In the first to third columns of the sensor chip 25A in FIG. 11 (2), the image signal light is read and the ranging light source 40 is turned on in the even-numbered period when the imaging light source 12 is turned on. In the second period, the ranging signal light is read.
Since the ranging signal light is red light, only the first column of the sensor chip 25A corresponding to red generates the ranging signal in the odd-numbered period.

  With the above-described configuration, the distance measuring sensor and the image sensor can be shared, so the sensor chip 25A is a sensor dedicated to the distance measuring sensor as shown in the fourth row of the sensor chip 25 (shown in FIG. 5 (2)). The sensor chip can have a simple configuration.

In the first embodiment, when the color filter of the image sensor (first to third columns) of the sensor chip 25 is configured to completely block infrared light, the image sensor uses infrared light (ranging signal). Light) is completely shielded. However, when the color filter cannot completely block the distance measuring signal light (infrared light), the distance measuring signal light (infrared light) is read by the image sensor, and the distance measuring signal light is converted into an image (signal light). ) Is superimposed as noise.
In the present embodiment, since the imaging light source 12 and the ranging light source 40 are controlled to be lit at different times, noise superimposed on the image as described above can be effectively suppressed.
Further, the color filters (R, G, B) provided on the first to third rows of the sensor chip 25A do not need to be configured to completely block infrared light. Can be configured.

In addition to the above, many methods are conceivable as methods for separating the reading of the image signal light and the ranging signal light in terms of time.
For example, in the above description, the case where the illumination light for imaging of the imaging light source 12 is white light has been described. However, when the imaging light source 12 sequentially turns on the respective monochromatic lights of RGB, FIG. As described above, the sensor chip 25B configured only by the first column may be used.
The case where the monochromatic light is sequentially turned on is, for example, a case where the imaging light source 12 lights R in the period K1, G in the period K2, and B in the period K3. Further, in the period K4, the ranging light source 40 lights R.
The sensor chip 25B reads R image signal light in the period K1, G image signal light in the period K2, and B image signal light in the period K3. The sensor chip 25B reads the ranging signal light in the period K4. Further, after the period K5, the above-described reading pattern is repeated.
With the configuration as described above, the image sensor can read each of R, G, and B only in the first column, so the sensor chip 25B configured in the first column can be used.

Embodiment 4 FIG.
FIG. 13 is a diagram showing a timing chart at which the ranging light sources 40a to 40d are turned on according to the fourth embodiment of the present invention. In the figure, the vertical axis represents the light amount of the distance measuring light source 40, and the horizontal axis represents time (time). The present embodiment is different from the above-described embodiment in that the distance measuring light source 40 is not simply simply turned on (turned on) / off (turned off), but also changes the amount of light.
In FIG. 13, the ranging light source 40 is controlled so that the light amount of the ranging light source 40 increases in the order of the periods K1 to K5. A series of controls similar to those in the periods K1 to K5 are performed for the period K6 and thereafter.

  This embodiment can be applied to all of the above-described first to third embodiments. However, in order to simplify the description, a signal for image acquisition and distance measurement for each embodiment 1 (periods K1, K2,... In the following, description will be made by taking as an example the case of application to the case of simultaneously reading signals for use.

For example, the light amount Id of the distance measuring light source 40 in the period K1 is 1, the light amount Id in the period K2 is 2, the light amount Id in the period K3 is 3, the light amount Id in the period K4 is 4, and the light amount Id in the period K5 is 5. The embodiment will be described.
For example, assuming that the reflectance of the reading object 1 is 50%, when the light amount Id in the period K2 is 2 in the periods K1 to K5, the output is not sufficiently saturated (when the sensor chip 25 receives the light amount of Id = 1). The distance measurement signal is obtained by the sensor chip 25.
In the period K1 in which the light amount Id is smaller than the period K2, the distance measurement signal output (corresponding to the case where the sensor chip 25 receives the light amount of Id <1) is small and insufficient. On the other hand, in the periods K3 to K5 where the light amount Id is larger than the period K2, the output of the distance measurement signal (corresponding to the case where the sensor chip 25 receives the light amount of Id> 1) is saturated. A signal output obtained in a period other than the above-described period K2 is not used as a distance measurement signal.
In the above example, only the output of the sensor chip 25 in one cycle is used as the ranging signal in the plurality of periods K1 to K5, but the output of the sensor chip 25 in the plurality of cycles may be used as the ranging signal.

  The reading object 1 has a large number of patterns and colors, and the amount of light received by the sensor chip 25 after the distance measuring illumination light is reflected and scattered by the reading object 1 also varies depending on the reflectance of the reading object 1. Therefore, depending on the reflectance of the reading object 1, there is a problem that the distance measurement signal output from the sensor chip 25 is saturated or the output of the distance measurement signal generated by the sensor chip 25 is reduced.

  According to the fourth embodiment, even when reading the reading object 1 composed of a plurality of ranges having different reflectances, a ranging signal having an appropriate output can be selected and used. The occurrence of such a problem can be suppressed, and the floating amount of the reading object 1 with respect to the top glass 11 can be accurately measured.

Embodiment 5. FIG.
14 and 15 are diagrams illustrating an example of a timing chart when the distance measuring light source 40 according to the fifth embodiment is turned on. 14 and 15, the horizontal axis indicates time (time), and the vertical axis indicates the ON / OFF state of the distance measuring light source 40. This embodiment is different from the above-described embodiment in that the distance measuring light sources 40 adjacent to each other are controlled so as not to be turned on simultaneously.
In FIG. 14, a case where four distance measuring light sources 40a to 40d are used will be described as an example. In FIG. 15, a case where six distance measuring light sources 40a to 40f are used will be described as an example. The number of ranging light sources 40 is not limited to the above example.

FIG. 14 shows a case where the distance measuring light source 40 is turned on by skipping one of the plurality of distance measuring light sources 40a to 40d. In this case, for example, a first lighting pattern (corresponding to a portion surrounded by a broken line in the drawing) shown in the period K1 and a second lighting pattern (corresponding to a portion surrounded by a dotted line in the drawing) shown in the period K2 are provided. Yes, the two lighting patterns are controlled so as to be sequentially switched in each period.
Hereinafter, only the ranging light source 40 that is turned on (ON) will be described, and the description of the ranging light source 40 that is turned off (OFF) may be omitted.
For example, in the period K1, the distance measuring light sources 40a and 40c are simultaneously turned on (first lighting pattern), and in the period K2, switching to the distance measuring light sources 40b and 40d is simultaneously turned on (second lighting pattern).
The first lighting pattern corresponds to odd-numbered periods (K1, K3, K5, K7) in the figure, and the second lighting pattern corresponds to even-numbered periods (K2, K4, K6, K8) in the figure. Corresponding to

FIG. 15 shows a case where the distance measuring light source 40 is turned on by skipping three of the plurality of distance measuring light sources 40a to 40d. In this case, for example, there are four lighting patterns shown in the periods K1 to K4, and the four patterns are controlled to be sequentially switched in each period.
In the figure, the first lighting pattern, the second lighting pattern, the third lighting pattern, and the fourth lighting pattern are respectively an area surrounded by a broken line, an area surrounded by a solid line, and an area surrounded by a dotted line. , Corresponding to the area surrounded by the alternate long and short dash line.
Specifically, in the period K1, the ranging light sources 40a and 40e are turned on simultaneously (first lighting pattern), and in the period K2, the ranging light sources 40b and 40f are turned on (second lighting pattern). Switch. In the period K3, the distance measuring light source 40c is switched to lighting (third lighting pattern), and in the period K4, the distance measuring light source 40d is switched to lighting (fourth lighting pattern).

In the above description, the distance measurement light source 40 is turned on by skipping one or three. However, the present invention is not limited to the above example, and the distance measurement light source 40 may be turned on by skipping two or four or more. Good.
When the plurality of distance measuring light sources 40 are controlled to be turned on with n (n is a natural number), there are (n + 1) lighting patterns that can be assumed.
In FIG. 14 and FIG. 15, the lighting pattern is switched for all the (n + 1) lighting patterns, but the lighting pattern switching is performed for only a part (two or more lighting patterns) of all the lighting patterns. May be performed. Alternatively, the distance measuring light source 40 may be turned on only with the same lighting pattern without switching the lighting pattern.
Furthermore, in FIG. 14 and FIG. 15, the lighting pattern is switched for each period, but may be performed for a plurality of periods.

In the image reading apparatus of the first embodiment (FIGS. 2 and 3), for example, when the adjacent distance measuring light sources 40a and 40b are turned on simultaneously, the light emitted from the distance measuring light source 40b is emitted from the imaging optical element 15b. The sensor chip 25b may receive the reflected light (stray light) that is reflected toward the sensor chip 25b.
On the other hand, in the present embodiment, since the lighting control of each distance measuring light source 40 is performed so that the adjacent distance measuring light sources 40 are lit at different times, unnecessary stray light to the distance measuring signal light can be suppressed. As a result, the accuracy in ranging can be improved.

  Compared to FIG. 14, in FIG. 15, control is performed so as to reduce the distance measuring light source 40 that is turned on simultaneously. Controlling in this way has effects such as extending the life of the ranging light source 40 and reducing power consumption. As described in the fourth embodiment, the ranging signal light may be read at a preset time interval.

DESCRIPTION OF SYMBOLS 1 Reading object, 11 Top plate glass, 12 Imaging light source, 13 Illumination light, 14 Imaging system array, 15 Imaging optical element, 16 Illumination light scattered by the reading object 1, 17 Condensed light, 18 Lens (light condensing part), 19 stop, 20 lens (imaging part), 21 light passing through stop 19, 22 imaging surface, 23 holder, 24 holder, 25 sensor chip, 28 image processing part, 29 sensor substrate, 31 Imaging reading range, 32 Overlapping imaging range, 33 Imaging reading range, 34 Imaging visual field range, 35 Optical axis, 40 Distance measuring light source (auxiliary light source), 41 Irradiation area, 42 Transfer area, 50 Original image, 51 Output image data.

Claims (12)

An imaging light source that illuminates a reading object with illumination light;
A condensing part for condensing the illumination light scattered by the reading object, and an image forming part for forming an image of the reading object by forming an image of the condensed illumination light, A plurality of imaging optical elements respectively disposed in the main scanning direction;
A plurality of sensor chips for reading each of the images formed by the plurality of imaging optical elements;
An auxiliary light source that irradiates the reading target object with auxiliary signal light directed from the imaging unit of the target imaging optical element that is a target imaging optical element among the plurality of imaging optical elements,
The image reading apparatus, wherein the auxiliary light source is arranged such that a sensor chip that reads an image of an adjacent imaging optical element adjacent to the target imaging optical element reads the auxiliary signal light. When the range on the reading object that can be imaged on the reading surface of the sensor chip corresponding to each of the plurality of imaging optical elements is an imaging reading range,
The image reading apparatus according to claim 1, wherein at least a part of the reading object irradiated with the auxiliary signal light is included in an imaging reading range of the adjacent imaging optical element. When the light scattered in each imaging reading range is collected and imaged, a space through which the light beam emitted from the imaging unit of each imaging optical element can pass is defined as an imaging visual field space.
When the range of the object to be read that can be condensed by the focusing unit of each imaging optical element is an imaging reading range, the light scattered in each imaging reading range is condensed and imaged. When the space through which the light beam emitted from the imaging portion of each imaging optical element can pass is defined as the imaging field space,
At least a part of the light emitting surface of the auxiliary light source is located inside the imaging field space of the target imaging optical element corresponding to the auxiliary light source and outside the imaging scanning field space of the target imaging optical element in the main scanning direction. The image reading apparatus according to claim 2, which is arranged.   The at least part of the light emitting surface of the auxiliary light source is disposed on a sensor chip that reads an image of the target imaging optical element, spaced apart in the main scanning direction and overlapping in the sub scanning direction. The image reading apparatus according to claim 3.   2. An image processing unit that performs image restoration processing on a plurality of image data generated by the plurality of sensor chips using auxiliary data generated by the sensor chip that has read the auxiliary signal light. The image reading device according to claim 4. Each of the plurality of sensor chips has a plurality of imaging elements arranged in the main scanning direction,
The image processing unit
Using the auxiliary data, a light receiving position that is a position in the main scanning direction is calculated for the image sensor that has read the auxiliary signal light among the plurality of image sensors included in the sensor chip that has read the auxiliary signal light,
Based on the light receiving position and the position of the auxiliary light source irradiated with the auxiliary signal light, the amount of floating in the height direction from the top plate on which the reading object is arranged to the reading object is calculated, and the amount of floating The image reading apparatus according to claim 5, wherein the image restoration processing is performed based on the image. The image reading apparatus according to any one of claims 1 to 6, wherein the auxiliary light source and the plurality of sensor chips are mounted on the same substrate. The sensor chip is
An image reading sensor for reading the illumination light which is visible light;
The image reading device according to any one of claims 1 to 7, further comprising a distance measuring sensor that reads the auxiliary signal light that is infrared light or ultraviolet light. The sensor chip is
An image reading sensor having a first shutter having a light shielding function and reading the illumination light;
A second shutter having a light shielding function, and a distance measuring sensor for reading the auxiliary signal light,
The opening and closing of the first shutter and the second shutter are controlled so that the reading time of the image does not overlap with the reading time of the auxiliary signal light. The image reading apparatus described in 1. The control according to any one of claims 1 to 7, wherein the auxiliary light source is turned on and the imaging light source is turned off in synchronization with a reading time of the auxiliary signal light by the sensor chip. Image reading device. The image reading apparatus according to any one of claims 1 to 10, wherein the auxiliary light source is controlled to emit light with a different light amount for each reading period of the auxiliary signal light by the sensor chip. The auxiliary light sources are plural,
The image reading apparatus according to any one of claims 1 to 11, wherein the plurality of auxiliary light sources are controlled such that two auxiliary light sources adjacent to each other among the plurality of auxiliary light sources are turned on at different timings. .

Images