JP7069964B2 - Image reader - Google Patents

Description

The present invention relates to an image reading device that reads an image of an object to be read.

In an image reader used in a copier, a banknote reader, a scanner, a facsimile, or the like, a plurality of sets of an imaging lens and a line image sensor are arranged in the main scanning direction.

The imaging lens of the image reader collects the light scattered by the object to be read that is moved in the sub-scanning direction, and forms the condensed light on the image plane of the line image sensor. An image of the object to be read is formed on the image plane.

In a general image reader, a plurality of imaging lenses arranged in the main scanning direction have a part of the field of view, which is a range for condensing light scattered by an object to be read, arranged next to each other. In many cases, it is arranged so as to overlap a part of the field of view of the imaging lens. In this case, when compositing 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 the method for acquiring the duplicated information described above, for example, 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. (See, for example, Patent Document 1). Here, first, the light of the marker irradiation light source reflected by the marker is read by the line image sensor to generate an auxiliary signal for image combination. Next, the duplicate information is estimated by comparing the two auxiliary signals generated by the line image sensors adjacent to each other.

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

Japanese Unexamined Patent Publication No. 2009-171003 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, but when each imaging lens is miniaturized as in Patent Document 2, the reading range of each imaging lens is widened. 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 is narrowed, it is not possible to provide the space for arranging the marker generation 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 process cannot be properly performed.

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

The image reader according to the present invention forms an image of an imaging light source that illuminates an object to be read with illumination light, a condensing unit that condenses the illumination light scattered by the object to be read, and the condensed illumination light. As a result, each has an imaging unit that forms an image of the object to be read, and a plurality of imaging optical elements arranged in the main scanning direction and a plurality of images formed by the plurality of imaging optical elements are read. The reading object is irradiated with auxiliary signal light that passes through the image forming portion of the target imaging optical element, which is the target imaging optical element among the plurality of imaging optical elements, and heads toward the condensing portion. An auxiliary light source is provided, and the auxiliary light source is arranged so 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.

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

It is a schematic sectional drawing in the sub-scanning direction (Y direction) of the image reading apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the image reading apparatus which concerns on Embodiment 1 of this invention. It is a perspective view which shows the image reading apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the relationship between the imaging reading range and the imaging reading range of a plurality of imaging optical elements. It is explanatory drawing for concretely explaining the sensor chip of Embodiment 1 of this invention. It is a schematic diagram regarding the relationship of the image formation position by the image formation optical element located adjacent to each other. It is a flowchart for demonstrating the operation of the image processing part which concerns on Embodiment 1 of this invention. It is a flowchart explaining the calculation process of the float amount z in step 3 in FIG. It is explanatory drawing for demonstrating the image restoration process in detail. It is a timing chart for demonstrating the operation 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 which shows the timing chart which lights the light source for image pickup and the light source for distance measurement which concerns on Embodiment 3 of this invention. It is a figure which shows the timing chart which the light source for distance measurement which concerns on Embodiment 4 of this invention is turned on. It is a figure which shows an example of the timing chart which lights a light source for distance measurement which concerns on Embodiment 5 of this invention. It is a figure which shows another example of the timing chart which the light source for distance measurement which concerns on Embodiment 5 of this invention is turned on.

Embodiment 1.
The close 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 target, and is, for example, a facsimile, a copier, a scanner, a multifunction device, a financial terminal, or an industrial inspection device. It is installed in such as. The object to be read is, for example, a manuscript, a mark sheet, a banknote, a check or other securities.
In the following figures, the X, Y, and Z directions will be described as indicating the main scanning direction, the sub-scanning direction, and the height direction, respectively.

FIG. 1 is a schematic cross-sectional view of the image reading device 101 according to the first embodiment of the present invention in the sub-scanning direction (Y direction). FIG. 2 is a cross-sectional view showing the image reading device 101, and FIG. 3 is a perspective view showing the image reading device 101 according to the first embodiment of the present invention. In FIGS. 2 and 3, the housing 10 is omitted for the convenience of easy viewing. Further, in FIGS. 1 and 3, the configurations of the holders 23 and 24 and the like are omitted.

In FIGS. 1 to 3, the reading object 1 is placed on the top glass 11 of the image reading device. In the scanner device, in order to scan the paper document or the like which is the scanning object 1, the scanning object 1 is moved on the top plate glass 11 in the sub-scanning direction which is the Y direction in the drawing.
In the office copier, 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 rested on the top plate glass 11. The glass. The moving direction may be either the + Y direction (positive Y direction) or the −Y direction (negative Y direction).

The image reader 101 corresponds to a housing 10, an image pickup light source 12, an image pickup system array 14, a holder 23, a holder 24, a plurality of sensor chips 25a to 25d, ..., And a plurality of distance measuring light sources (“auxiliary light sources”). ) 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 distance measuring light sources 40a to 40d ... Are collectively referred to as "imaging optical element 15", "sensor chip 25", and "measurement", respectively. It may be simply called "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 on the right side of the imaging optical element 15d (lens 18d, aperture 19, lens 20d). Pairs are arranged.

The housing 10 shown in FIG. 1 houses or holds each configuration of the image reading device 101 inside.

The image pickup light source 12 illuminates the reading object 1 with the illumination light 13. The illumination light 13 from the image pickup light source 12 becomes the illumination light 16 scattered by the reading object 1 by being illuminated by the reading object 1. More specifically, the image pickup 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 the illumination light 13 (shown by the dotted arrow in FIG. 1).
The image pickup light source 12 is composed of, for example, an LED (Light Lighting Diode) as a light source and a light guide body such as a resin for converting the light emitted from the LED into the illumination light 13 of the reading object 1. Can be done. This light guide is a columnar light guide extending in the main scanning direction. The illumination light 13 is, for example, white light containing components such as red, green, and blue, but is not limited to this.

The imaging system array 14 has a plurality of imaging optical elements 15a to 15d ... (Sometimes collectively referred to as "imaging optical element 15"), and is arranged in each of the main scanning directions (X direction). Ru.

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 only an example, and the imaging system array 14 may have a configuration having a plurality of (two or more) imaging optical elements 15.

The plurality of imaging optical elements 15 form an image of a condensing unit (corresponding to the “lens 18” described later) that condenses the illumination light 16 scattered by the object 1 to be read, and the condensing illumination light 16. Each of the image forming portions (corresponding to the “lens 20” described later) forming an image of the object to be read 1 is provided.
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 object 1 to be read.
The diaphragm 19 is an optical component that blocks a part of the light 17 focused by the lens 18. The lens 20 forms an image of the light 21 that has passed through the diaphragm 19 on the image plane 22.
In FIGS. 2 and 3, the imaging optical element 15 is composed of a pair of lenses (lens 18 and lens 20). For example, the imaging optical element 15 is a single lens 18 or lens 20. It may be composed of lenses, or may be composed of three or more lenses.

The two holders 23 and 24 hold a plurality of imaging optical elements 15 (imaging system array 14) inside the housing 10 shown 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 of (for example, four or more) imaging optical elements 15a to 15d.
More specifically, as shown in FIGS. 2 and 3, the plurality of sensor chips 25a to 25d ... read images in the imaging reading range 31a to 31d ... Generated by the imaging optical elements 15a to 15d. 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 for the distance measuring light source 40 may be referred to as a “target imaging optical element 15”.
The plurality of distance measuring light sources 40a to 40d ... Are on the opposite side of the reading object 1, that is, the lens 20 (imaging unit) with respect to each lens 20 (imaging unit) of the plurality of object imaging optical elements 15a to 15d. ), It is arranged closer to the sensor board 29 than the object to be read.

Further, the distance measuring light sources 40a to 40d ... Are the distance measuring signal light (FIGS. 2 and 3) directed from the lens 20 (imaging unit) of the target imaging optical elements 15a to 15d ... to the lens 18 (condensing unit), respectively. Corresponds to the broken line portion in the above) is applied to the object to be read 1 via the target imaging optical elements 15a to 15d.
In FIG. 3, the regions where the distance measuring light sources 40a to 40d ... Irradiate the reading object 1 are the irradiation regions 41a to 41d, respectively. Hereinafter, the irradiation areas 41a to 41d ... may be collectively referred to as “irradiation area 41”.

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

Further, the ranging 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 ranging signal light via the adjacent imaging optical element 15. Will be done. The ranging signal light may be hereinafter referred to as "auxiliary signal light".

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

It is preferable that the distance measuring light source 40 is composed of a bare chip type LED having no package. With the above configuration, the LED can be mounted using the wiring pattern formed on the sensor board 29, and the LED can be mounted directly on the sensor board 29 without preparing a separate board for mounting the LED. be able to.

As described above, the distance measuring light source 40 is arranged on the side opposite to the object to be read 1 with respect to the object imaging optical element 15, even when the space between the imaging optical elements 15 described above is small. It has the effect of being able to obtain a ranging signal as an auxiliary signal for image coupling.
In the figure, a configuration in which a plurality of distance measuring light sources 40a to 40d ... Are provided is shown, but the distance measuring light source 40 is an imaging optical element 15 of at least one of a plurality of imaging optical elements 15a to 15d. It suffices if it is provided in. Further, a plurality of distance measuring light sources 40 may be arranged so as to correspond to each imaging optical element 15.

The image processing unit 28 uses a plurality of sensor chips 25a by using the distance measuring signals (hereinafter, may be referred to as “auxiliary data”) generated by the sensor chips 25a to 25d ... that read the distance measuring signal light. Image restoration processing is performed on a plurality of image data generated by ~ 25d .... More specifically, the image processing unit 28 performs image restoration processing described later based on the distance measurement signal to superimpose a plurality of image data (reduced transfer images).

FIG. 4 shows the imaging reading ranges 31a to 31d ... (corresponding to the diagonally striped portion in the figure), the overlapping imaging ranges 32a to 32c ... It is a schematic diagram showing the image formation reading range 33a to 33d ... (corresponding to the portion surrounded by the broken line in the figure). In the figure, 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 in a straight line with overlap.

5A and 5B are explanatory views for specifically explaining the sensor chips 25a to 25d ... And the distance measuring light sources 40a to 40d ... Of the first embodiment of the present invention, and FIG. A figure is shown, and FIG. 2 (2) shows an enlarged view of a set of a range-finding light source 40 and a sensor chip 25 from the figure (1).

As shown in FIGS. 5 (1) and 5 (2), each sensor chip 25 is a line-shaped chip arranged on the sensor substrate 29 and having a plurality of image pickup elements 250 arranged in the X direction.
The sensor chip 25 of the present embodiment has an image sensor that reads an image of an object to be read, and a distance measuring sensor that reads a distance measuring signal light.
In the figure, assuming that the image sensor 250 of the sensor chip 25 is in the first to fourth rows from the top, when reading a color image, as shown in FIG. 5 (2), the image sensor is in the first row to the fourth row. It is composed of three rows of image pickup elements 250 in total. The image sensor 250 in the first row reads red light (R), the image sensor 250 in the second row reads green light (G), and the image sensor 250 in the third row 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 range-finding light source 40 can be configured by, for example, an LED that emits near-infrared light. The ranging signal light (IR) emitted by the ranging light source 40 is read by the fourth row of the sensor chip 25.

Here, before explaining the arrangement of the sensor chip 25 and the distance measuring light source 40 in more detail, the optical range related to the imaging optical element 15 and the sensor chip 25 is defined with reference to FIGS. 2 to 5.

The imaging reading range 31a to 31d ... (hereinafter, may be collectively referred to as "imaging reading range 31") are sensor chips 25a to 25d corresponding to each of the plurality of imaging optical elements 15a to 15d. It is the range of the reading object 1 that can be imaged on the reading surface of.
In the overlapping imaging ranges 32a to 32c ... (hereinafter, may be collectively referred to as "overlapping imaging range 32"), the imaging reading ranges 31 of the plurality of imaging reading ranges 31a to 31d ... overlap each other. 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 in which a part of two adjacent two imaging reading ranges 31 out of a plurality of imaging reading ranges 31 overlap.

The image formation reading range 33a to 33d ... (The image formation reading range 33 may be collectively referred to as "image formation reading range 33") means that an optical image is formed on the image formation surface 22 by each image formation optical element 15. It is a range on the reading object 1.
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 chipped image is not generated on the sensor chip 25.
The image formation visual field range 34a to 34d ... (hereinafter, may be collectively referred to as "imaging visual field range 34") is an image formation surface on which the image formation reading range 33 is transferred by the image formation 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 light emitting surface of the distance measuring light source 40 is arranged within the imaging field of view range 34 of the imaging surface 22. Further, the distance measuring light source 40 is placed on the sensor substrate 29 so that its light emitting surface is separated from the sensor chip 25 in the X direction and has an overlap in the Y direction.
By arranging as described above, the distance measuring light source 40 has an effect that it is easy to irradiate the image pickup reading range 31 of the adjacent sensor chip 25.

Here, with reference to FIG. 6, the operation of the distance measuring signal light emitted by the distance measuring light source 40b will be described in detail. 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 object to be read 1 is separated from the top plate glass 11 by a floating amount z, and the reduction magnification from the object to be read 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. It is assumed that the imaging optical elements 15b and 15c are separated by the 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 object to be read 1 with emitted light, and the imaging optical element 15c arranged adjacent to the target imaging optical element 15b (hereinafter referred to as “ An image is formed at a point P2 on the imaging reading range 31c of the "adjacent imaging optical element").
More specifically, when the distance measuring light source 40b is turned on, the emitted light is focused by the lens 20b of the target imaging optical element 15b, and the focused light rays pass through the aperture 19b of the target imaging optical element 15b. The light beam is focused on the object to be read 1 by the lens 18b of the object imaging optical element 15b. Since the image plane 22 and the object 1 to be read are in a conjugated 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 object 1 to be read. Further, an image of the light emitting surface of the distance measuring light source 40b is formed in the irradiation region 41b on the reading object 1.

Since the distance measuring light source 40b is arranged apart from the sensor chip 25b in the X direction, the irradiation region 41b on which the image of the light emitting surface of the distance measuring light source 40b is formed is outside the image pickup 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 rays forming the image of the light emitting surface in the irradiation region 41b are reflected and scattered by the object to be read 1, they are focused on the image plane 22 by the image formation optical element 15c adjacent to the image formation optical element 15b. .. Since the image plane 22 and the object 1 to be read are in a conjugated relationship, the point P2 on the object 1 to be read forms an image on the light receiving point P3 on the image plane 22.

Then, 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. 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 region 41b of the object to be read 1 is further transferred by the adjacent imaging optical element 15c, and the image of the light emitting surface is formed in the transfer region 42b on the image plane 22. ..

In the above description, the case where the entire range of the light emitting surface of the distance measuring light source 40b is within the range of the imaging field of view range 34b has been described. It may be included in 34b.

The case where the light emitting surface of the distance measuring light source 40 is arranged on the image forming surface 22 is taken as an example, but at least a part of the irradiation area 41 irradiated with the distance measuring signal light is adjacent to the target imaging optical element 15. As long as the distance measuring light source 40 is arranged so as to be included in the image pickup reading range 31 of the adjacent imaging optical element 15, the arrangement may be other than the above.

Here, in order to explain the spatial arrangement of the distance measuring light source 40, the imaging visual field space and the imaging visual field space are defined below.
In the imaging visual field space, when the light scattered in each imaging reading range 33 is focused and imaged, the light flux emitted from the lens 20 (imaging unit) of each imaging optical element 15 passes through. It is a possible space.
In the imaging field space, the luminous flux emitted from the lens 20 (imaging unit) of each imaging optical element 15 can pass through when the light scattered in each imaging reading range 31 is focused and imaged. Space.

In the above description, the case where the light emitting surface of the distance measuring light source 40 is arranged on the image plane 22 is 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 may be provided at a distance) and inside the imaging visual field space.

Further, the distance measuring light source 40 may be arranged as follows in the above-mentioned space. The cut surface when the imaging field space is cut in a plane parallel to the object 1 to be read (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. Moreover, it may be arranged so as to have an overlap in the Y direction with respect to the cut surface.
By arranging as described above, the distance measuring signal light of the distance measuring light source 40 is surely 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. 7. 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 the image data generated by the sensor chip 25 (step S1).

Specifically, the first to third rows of the sensor chip 25 read the reduced transfer image corresponding to each of the three colors of RGB formed by the imaging optical element 15. Further, the fourth row of the sensor chip 25 is used as a sensor for reading infrared light (IR) and measuring the floating amount z of the reading object 1 with respect to the top plate 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 rows of the sensor chip 25 described above is an example, and the number of rows may be appropriately changed. As will be described in detail in the embodiment described later, depending on the control method of the image pickup light source 12 and the distance measurement light source 40 and the control method of the sensor chip 25, the image sensor and the distance measurement sensor are read by a common sensor. You may do so.

The image processing unit 28 acquires the 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 at the same time.

Specifically, since the distance measuring light source 40b emits infrared light, it is not imaged (read) by the first to third rows (RGB) of the sensor chip 25c, but is imaged by the fourth row. The 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 imaged by the fourth row of the sensor chip 25c.
With the above configuration, the 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 calculation processing with respect to the floating amount z of the reading object 1 with respect to the top plate glass 11 using the distance measuring signal (step S3).

Using the finally calculated floating amount z, the image processing unit 28 performs an image restoration process (details will be described later) on a plurality of image data (step S4).

Here, step S3 of FIG. 7 will be described in detail with reference to FIGS. 6 and 8. FIG. 8 is a flowchart illustrating the operation of step S3 in detail.

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

The initial setting value includes position information (information about the imaging optical element 15, the imaging optical element 15, the sensor chip 25, and the distance measuring light source 40). The position information may be, 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.) Is included.
Here, the light source position ΔX0 is, as shown in FIG. 6, the distance in the main scanning direction between the optical axis 35b of the target imaging optical element 15b and the light emitting point P1 of the distance measuring light source 40b.

Subsequently, the image processing unit 28 calculates the light receiving position ΔX2, which is the position of the image pickup element 250 that has received the distance measurement signal light among the plurality of image pickup elements 250, based on the distance measurement signal (step S32).
As shown in FIG. 6, the light receiving position ΔX2 is the 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. More specifically, the image processing unit 28 uses the image pickup device 250 located on the optical axis 35c of the adjacent imaging optical element 15c as a reference, and determines the number of pixels from this reference to the image pickup device 250 that has received the ranging signal. Calculated as the light receiving position ΔX2.

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

Since the imaging point P3 formed by the imaging optical element 15c at the point P2 is separated from the optical axis 35c by the light receiving position ΔX2, the equation (3) holds.
ΔX2 = M (z) · ΔX1'... (3)

Further, the equation (4) is established from the equations (1) to (3).
ΔX2 = M (z) · P−ΔX0… (4)

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

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

Substituting Eq. (5) into Eq. (4), Eq. (6) holds. Equation (6) represents the relationship between the float amount z and the light receiving position ΔX2.
ΔX2 = P · Xs / Xf (z) −ΔX0
= P · Xs / (xf + α · z) −ΔX0… (6)

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

In the above description, the floating amount z is calculated using the above-mentioned initial setting value, but generally, the size 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, the 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 process in detail. The figure shows the case where the original image 50 of the object 1 to be read is read by the three sensor chips 25a to 25c and the three output image data 51a to 51c are generated. 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. 9 (1) is an example of the original image 50 of the object to be read 1. FIG. (2) shows an example in which the output image data 51a to 51c are arranged when the original image 50 is placed on the top plate glass 11, that is, when the floating amount z is 0. FIG. (3) shows a diagram showing the imaging reading ranges 31a to 31c and the overlapping imaging ranges 32a to 32b of the figure (2) on the original image 50. FIG. 4 (4) is output image data 51a to 51c when the floating amount z is larger than 0. FIG. 5 (5) is a diagram showing the imaging reading ranges 31a to 31c and the overlapping imaging ranges 32a to 32b of FIG. 4 (4) on the original image 50.

(A) Image combination position calculation process Using the above-mentioned initial setting value, the width XOL (z) of the overlapping imaging range 32 when the floating amount is z is expressed by the equation (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), images are duplicated at the boundary between the output image data 51a and the output image data 51b, but by calculating the width XOL of the overlapping imaging range 32, (c). ) The image combination process can be performed appropriately.

(B) Image scaling processing In image scaling processing, the reduction magnification M (z) is calculated by substituting the floating amount z into the equation (1), and the output image data is used using this reduction magnification M (z). The 51a to 51c are adjusted to the dimensions (main scanning direction) corresponding to the original image 50.
For example, the width of the image pickup reading range 31a, 31b, 31c in FIG. 9 (5) in the X direction is larger than that in FIG. 9 (3), and the output image data 51a, 51b, 51c in FIG. 9 (4) are It can be seen that the image is reduced in the X direction as compared with that in FIG. 9 (2). Even for such an output image reduced in the X direction, the size of the image can be appropriately adjusted by performing the above-mentioned image scaling processing.

(C) Image combination processing The image processing unit 28 uses the image restored by the above-mentioned processing (a) in the overlapping imaging range in the adjacent boundary range based on the width XOL (z) of the overlapping imaging range 32. This is a process of creating an image in which 32 widths XOL are superimposed.

In step S3, when the image processing unit 28 obtains the floating amount z for two adjacent imaging reading ranges 31 out of the plurality of imaging reading ranges 31, the floating amount z is obtained for each of the two adjacent imaging reading ranges 31. , The above-mentioned processes (a) to (c) may be performed.
According to the above configuration, the floating amount z may change depending on the position in the X direction, but since an appropriate floating amount z can be obtained in each of the two adjacent imaging reading ranges 31, an image with little deterioration can be obtained. Can be done.

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

The comparative example performs the following processing. First, the output image 51b is shifted in the (—X) direction with respect to the output image 51a shown in FIG. 9, and the sum of the absolute values of the differences between the two images is obtained. When the value of the difference absolute value sum 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 the absolute values of the differences, the width XOL of the overlapping imaging range 32 in the X direction is obtained, and the image combination position calculation process is performed.

As a result of diligent studies by the inventor, in (a) image combination position calculation processing of such a comparative example, depending on the pattern of the object to be read 1, the images are not properly superposed and the restored image is deteriorated. I found that there are cases where only can be obtained.

Examples of the reading object 1 in which it is difficult to properly superimpose the images include a blank image without image information in the overlapping imaging range 32, a pattern image repeatedly appearing in the X direction, and the like.

As an example of the range of blank paper without image information, there is a portion where the output image 51b and the output image 51c of FIG. 9 (2) overlap. In this portion, as shown in the overlapping imaging range 32b of FIG. 9 (3), only the background color does not include the portion corresponding to the characters.
At this time, even if the above (a) image combination processing is performed, the sum of the absolute values of the differences between the two images becomes a constant value regardless of the shift amount of the images, 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 grid pattern arranged at a fine pitch p in the X direction. At this time, the sum of the difference absolute values of the two images takes a minimum value for each pitch p, and it is not possible to determine which minimum value shift amount corresponds to the width XOL of the true overlapping imaging range 32.

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

Further, since the distance measuring light source 40 can be directly mounted on the sensor board 29, it is not necessary to separately prepare a light source board, and the number of parts can be reduced and the mounting can be performed compactly.

Embodiment 2.
The image reading device 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 to block 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 the shutter (second shutter) of the distance measuring sensor. It is also different from the first embodiment in that it is controlled so as to be.
As the shutter, the following description will be given using an electronic shutter that adjusts the exposure time by electronically controlling as an example, but a physical shutter that opens and closes a light-shielding mechanism that physically blocks light may be used. The 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. (1) and (2) are timing charts of an electronic shutter for an image and an electronic shutter for distance measurement, respectively. In the figure, the horizontal axis and the vertical axis indicate time and the open / closed state of the shutter.
The sensor chip 25 outputs four rows 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 on the electronic shutter in the CLOSE (closed state) is not read by the sensor chip 25 as a signal.

As shown in FIG. 10, in each reading cycle t of the sensor chip 25, the electronic shutters for image and distance measurement are not OPEN at the same time, that is, the reading time of the image signal light and the reading time of the auxiliary signal light are set. The opening and closing of the electronic shutter is controlled so as not to overlap.
Further, both light sources are controlled so that the image pickup 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 image pickup light source 12 is lit during the time when the electronic shutter for image is OPEN, and only the light source 40 for distance measurement is lit during the time when the electronic shutter for distance measurement is OPEN.

The sensor chip 25 can suppress the superposition of the distance measurement signal as noise on the image signal by reading the image signal light and the distance measurement signal light separately in time.

In the figure, of the reading cycle t of the sensor chip 25, the reading time of the image signal light is 0.8t, and the reading time of the distance measuring signal light is 0.2t.
In this way, by configuring the reading time of the image signal light to be longer than the reading time of the distance measuring signal light, it is possible to acquire the image data while suppressing the decrease in the reading time of the image signal light. Therefore, deterioration of the SN ratio (signal-to-noise ratio) of the image data can be suppressed.
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 appropriately changed.

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

In the first embodiment, the color filters in the first to third rows 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 distance measurement signal may be superimposed on the image signal as noise because the color filter has a slight transmittance in the wavelength band of IR.
In the present embodiment, even in the configuration using the above-mentioned simple color filter, it is possible to suppress the distance measurement signal from being superimposed on the image signal as noise.

Further, 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 the third embodiment described later). In comparison, in addition to the above-mentioned effect, it has the effect that the reading cycle t can be set longer.

Embodiment 3.
FIG. 11 is a diagram showing a sensor substrate 29A of the image reader according to the third embodiment of the present invention, and FIG. 12 is a diagram in which the image pickup light source 12 and the distance measuring light source 40 according to the third embodiment of the present invention are lit. It is a figure which shows the timing chart.
In the present embodiment, the image pickup light source 12 and the distance measurement light source 40 are controlled to light at different times, and the distance measurement sensor and the image sensor are shared. It is 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.
The image pickup illumination light emitted from the image pickup light source 12 is white light, and may be referred to as light from the distance measurement light source 40 emitted from the distance measurement light source 40 (hereinafter, referred to as “distance measurement illumination light”). .) Is, for example, red. In the present embodiment, the distance measuring illumination light does not necessarily have to be red, and may be blue, green, or white.

As shown in FIG. 12, the illumination light is switched in time. For the sake of simplification of the notation, the time t0 to t1 is referred to as the period K1, the time t1 to t2 is referred to as the period K2, the time t2 to t3 is referred to as the period K3, and so on. In FIG. 12, the distance measuring light source 40 and the imaging light source 12 are alternately lit, and the distance measuring light source 40 is lit in the odd-numbered period (K1, K3, K5 ...), And the even-numbered period (K2) is lit. , K4, K6 ...), The image pickup 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.
Further, control is performed so that the image pickup 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 ... The lengths of the odd-numbered period and the even-numbered period may be the same, but may be different.
The first to third rows of the sensor chip 25A in FIG. 11 (2) read the image signal light during the even-numbered period in which the image pickup light source 12 is lit, and the distance measurement light source 40 is lit in an odd number. In the second period, the distance measurement signal light is read.
Since the distance measurement signal light is red light, only the first row of the sensor chip 25A corresponding to red color generates the distance measurement signal in the odd-numbered period.

Since the distance measuring sensor and the image sensor can be shared by the above configuration, 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)). Can be omitted, and the sensor chip can be configured in a simple manner.

Further, in the first embodiment, if the color filter of the image sensor (first to third rows) of the sensor chip 25 is configured to completely block infrared light, the image sensor is configured to completely block infrared light (distance measuring signal). Light) is completely shielded. However, if the color filter cannot completely block the ranging signal light (infrared light), the ranging signal light (infrared light) is read by the image sensor, and this ranging signal light is used as the image (signal light). ) Has a problem of being superimposed as noise.
In the present embodiment, since the image pickup light source 12 and the distance measurement light source 40 are controlled to be turned on at different times, the 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, so that each color filter can be simplified. Can be configured.

In addition to the above, many methods can be considered as a method for temporally separating the reading of the image signal light and the distance measuring signal light.
For example, in the above description, the case where the image pickup illumination light of the image pickup light source 12 is white light has been described, but when the image pickup light source 12 sequentially lights each monochromatic light of RGB, FIG. 11 (3) As described above, the sensor chip 25B composed of only the first row may be used.
The case where the monochromatic light is sequentially turned on is, for example, a case where the image pickup 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 distance measuring light source 40 turns on R.
The sensor chip 25B reads the image signal light of R in the period K1, the image signal light of G in the period K2, and the image signal light of B in the period K3. The sensor chip 25B reads the ranging signal light during the period K4. Further, after the period K5, the above-mentioned reading pattern is repeated.
With the above configuration, the image sensor can read each of RGB only in the first row, so that the sensor chip 25B configured by the first row can be used.

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

This embodiment is applicable to all of the above-described first to third embodiments, but for the sake of simplicity, the first embodiment (periods K1, K2 ... Each period K1, K2 .... The following will be described as an example of the case where the signal is read at the same time.

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

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

According to the fourth embodiment, even when the reading object 1 composed of a plurality of ranges having different reflectances is read, the ranging signal having an appropriate output can be selected and used. It is possible to suppress the occurrence of such a problem, and it is possible to accurately measure the floating amount of the reading object 1 with respect to the top plate glass 11.

Embodiment 5.
14 and 15 are diagrams showing an example of a timing chart in which the distance measuring light source 40 according to the fifth embodiment is turned on. In FIGS. 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. The present 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 at the same time.
In FIG. 14, a case where four distance measuring light sources 40a to 40d are used will be described as an example, and 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 distance measuring 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, the first lighting pattern shown in the period K1 (corresponding to the part surrounded by the broken line in the figure) and the second lighting pattern shown in the period K2 (corresponding to the part surrounded by the dotted line in the figure). Yes, these two lighting patterns are controlled to be sequentially switched in each period.
Hereinafter, only the distance measuring light source 40 that is lit (ON) will be described, and the description of the distance measuring 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 lit (first lighting pattern), and in the period K2, the distance measuring light sources 40b and 40d are switched to the simultaneous lighting (second lighting pattern).
The first lighting pattern corresponds to the odd-numbered period (K1, K3, K5, K7) in the figure, and the second lighting pattern corresponds to the even-numbered period (K2, K4, K6, K8) in the figure. Corresponds 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 the area surrounded by the broken line, the area surrounded by the solid line, and the area surrounded by the dotted line, respectively. , Corresponds to the area surrounded by the alternate long and short dash line.
Specifically, in the period K1, the distance measuring light sources 40a and 40e are turned on at the same time (first lighting pattern), and in the period K2, the distance measuring light sources 40b and 40f are turned on (second lighting pattern). Switch. In the period K3, the lighting is switched to the lighting of the distance measuring light source 40c (third lighting pattern), and in the period K4, the lighting is switched to the lighting of the distance measuring light source 40d (fourth lighting pattern).

In the above, the case where the distance measuring light source 40 is turned on for one or three skips has been described, but the present invention is not limited to the above example, and the distance measuring light source 40 may be turned on for two or four or more skips. good.
When a plurality of distance measuring light sources 40 are controlled to be lit by skipping n (n is a natural number), there are (n + 1) lit patterns as possible lit patterns.
In FIGS. 14 and 15, the lighting patterns are switched for all of the above (n + 1) lighting patterns, but the lighting patterns are switched for only a part of all the lighting patterns (two or more lighting patterns). May be done. Further, the distance measuring light source 40 may be lit only with the same lighting pattern without switching the lighting pattern.
Further, in FIGS. 14 and 15, the lighting pattern is switched every one period, but it may be changed every a plurality of periods.

In the image reader of the first embodiment (FIGS. 2 and 3), for example, when the adjacent distance measuring light sources 40a and 40b are turned on at the same time, the light emitted by the distance measuring light source 40b is emitted by the imaging optical element 15b. It is reflected toward the sensor chip 25b, and the reflected light (stray light) may be received by 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 turned on at different times, unnecessary stray light to the distance measuring signal light can be suppressed, resulting in the result. It is possible to improve the accuracy in distance measurement.

Compared to FIG. 14, in FIG. 15, control is performed so as to reduce the distance measuring light source 40 that is lit at the same time. By performing the control in this way, there are effects such as extending the life of the distance measuring light source 40 and reducing power consumption. As described in the fourth embodiment, the distance measurement signal light may be read at preset time intervals.

1 Object to be read, 11 Top plate glass, 12 Light source for imaging, 13 Illumination light, 14 Imaging system array, 15 Imaging optical element, 16 Illumination light scattered by object 1 to be read, 17 Condensed light, 18 Lens (condensing part), 19 apertures, 20 lenses (imaging part), 21 light passing through the aperture 19, 22 image planes, 23 holders, 24 holders, 25 sensor chips, 28 image processing units, 29 sensor boards, 31 Imaging reading range, 32 Overlapping imaging range, 33 Imaging reading range, 34 Imaging 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 (13)

An imaging light source that illuminates the object to be read with illumination light,
Each has a condensing unit that collects the illumination light scattered by the reading object and an imaging unit that forms an image of the reading object by forming an image of the condensed illumination light. Multiple imaging optical elements arranged in the main scanning direction, respectively,
A plurality of sensor chips that read each of the images formed by the plurality of imaging optical elements, and
An auxiliary light source that irradiates the reading object with auxiliary signal light that passes through the image forming portion of the target imaging optical element, which is the target imaging optical element among the plurality of imaging optical elements, and heads toward the condensing portion. Equipped with
The auxiliary light source is an image reading device in which a sensor chip that reads an image of an adjacent imaging optical element adjacent to the target imaging optical element is arranged so as to read the auxiliary signal light. The image reading device according to claim 1, wherein the auxiliary light source is arranged on the side closer to the sensor chip in the height direction than the reading target with respect to the image forming portion of the target imaging optical element. .. 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 defined as the imaging reading range.
The image reading device according to claim 1 or 2 , wherein at least a part of the reading object irradiated with the auxiliary signal light is included in the imaging reading range of the adjacent imaging optical element. The space through which the light flux emitted from the imaging unit of each imaging optical element can pass when the light scattered in each imaging reading range is focused and imaged is defined as the imaging field space.
When the range of the object to be read that can be focused by the condensing unit of each of the imaging optical elements is set as the imaging reading range, the light scattered in each imaging reading range is condensed and imaged. Assuming that the space through which the light flux emitted from the image forming portion of each of the imaging optical elements can pass is defined as the imaging field space.
At least a part of the light emitting surface of the auxiliary light source is inside the imaging visual field space of the target imaging optical element corresponding to the auxiliary light source and outside the main scanning direction of the imaging visual field space of the target imaging optical element. The image reading device according to claim 3 , which is arranged. According to claim 1, at least a part of the light emitting surface of the auxiliary light source is arranged on a sensor chip that reads an image of the target imaging optical element so as to be separated in the main scanning direction and overlapped in the sub-scanning direction. The image reading device according to any one of claims 4 . Claim 1 further includes an image processing unit that performs image restoration processing on a plurality of image data generated by the plurality of sensor chips by using the auxiliary data generated by the sensor chip that has read the auxiliary signal light. The image reading device according to any one of claims 5 . Each of the plurality of sensor chips has a plurality of image pickup elements arranged in the main scanning direction.
The image processing unit
Using the auxiliary data, the light receiving position, which is the position in the main scanning direction, is calculated for the image pickup element that has read the auxiliary signal light among the plurality of image pickup elements 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 floating amount in the height direction from the top plate on which the reading object is arranged to the reading object is calculated, and the floating amount is calculated. The image reading device according to claim 6 , wherein the image restoration process is performed based on the above. The image reading device according to any one of claims 1 to 7 , 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 that reads the illumination light, which is visible light,
The image reading device according to any one of claims 1 to 8 , further comprising a distance measuring sensor for reading the auxiliary signal light which is infrared light or ultraviolet light. The sensor chip is
An image reading sensor having a first shutter having a light blocking function and reading the illumination light,
It has a second shutter having a light blocking function, and has a distance measuring sensor that reads the auxiliary signal light.
One of claims 1 to 8 , wherein the opening and closing of the first shutter and the second shutter are controlled so that the reading time of the image and the reading time of the auxiliary signal light do not overlap. The image reader according to the above. The aspect according to any one of claims 1 to 8 , wherein the auxiliary light source is controlled to be turned on and the image pickup light source is turned off in synchronization with the reading time of the auxiliary signal light by the sensor chip. Image reader. The image reading device according to any one of claims 1 to 11, wherein the auxiliary light source is controlled to emit light with a different amount of light for each reading cycle of the auxiliary signal light by the sensor chip. There are a plurality of auxiliary light sources,
The image reading according to any one of claims 1 to 12, wherein the plurality of auxiliary light sources are controlled so that two auxiliary light sources adjacent to each other among the plurality of auxiliary light sources are turned on at different timings. Device.

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