JPH07170397A - Image reader - Google Patents

Abstract

PURPOSE:To excellently read and process the images of various kinds of originals including thin originals such as slips, etc. CONSTITUTION:A reflection light quantity control part 25 varies and controls the reflection light quantity from a reference member 15 by the instruction from a system control part 1. Namely, after the reading of an original image is started, the reflection light quantity from a reference member 15 is controlled to M below a prescribed level, the reflection light quantity from the reference member 15 at the time of sampling correction data is varied and controlled according to the texture density of an original 12, transmission light quantity of the original 12 is measured just after the reading of an original image is started, the reflectance of the reference member 15 is controlled according to the transmission light quantity. Or, this device is provided with a first reference member having a reflectivity which is roughly equal to that of a standard white original and a second reference member having reflectivity which is sufficiently lower than that of the reference member, either one of them is selected, and it may be arranged just above a reading location.

Description

Detailed Description of the Invention

[0001]

This invention relates to an image scanner,
The present invention relates to an image reading device in a digital copying machine, a facsimile device or the like.

[0002]

2. Description of the Related Art In an image reading apparatus such as a scanner, a document is optically scanned by an optical system, a document image resulting from the reflected light is projected on an image sensor, and a document image is read by photoelectrically converting it into an image signal. And various image processings are performed on the image signal.

By the way, in such an image reading apparatus,
Sensitivity variation of image sensor, illuminance non-uniformity of light source,
Due to the aberration of the lens and the like, there is a problem that the output of the image sensor becomes non-uniform even when reading a document image of uniform density. This nonuniformity is usually called shading distortion. Therefore, in order to electrically correct this distortion, a reference member (white reference member) having a reflectance substantially equal to that of the standard white original is arranged on the optical path extension of the reading position of the original image, until the original is loaded. Is configured so that the image sensor can optically scan the reference member.

That is, prior to reading the original image,
The reference member is optically scanned with the light source turned on, the reflected light is received by the image sensor and converted into an image signal, and the obtained output level is stored in the memory as correction data for correcting shading distortion. Then, at the time of reading the original image, various image processing is performed after reading the correction data and correcting the distortion of the read image signal.

[0005]

However, in such a conventional image reading apparatus, the light emitted from the light source at the time of reading the original image is reflected on the original surface, and the irregularly reflected light is transmitted through the optical system to the image sensor. Although formed on the surface, a part of the light passes through the document and reaches the reference member, where it is reflected to illuminate the document from the back side. The amount of transmitted light depends on the paper quality of the original. The thicker the paper quality, the smaller the transmitted light amount, and the thinner the paper quality, the greater the transmitted light amount.

When the amount of transmitted light is small, the diffused reflected light from the original can be read well, but when reading an original image of thin paper such as a slip, the amount of light transmitted through the original is very large. The amount of light reflected from the reference member also increases accordingly. Further, the reflected light again passes through the original and is imaged on the image sensor together with the originally diffused reflected light, so that the reflected light from the reference member is superimposed on the image signal as an offset component, and the original image information is lost. become. That is, the offset component thins the image, degrading the reproducibility of the line drawing.

The present invention has been made in view of the above points, and enables even a thin original such as a slip to read and process the image thereof without impairing the reproducibility of the image. The purpose is to do so.

[0008]

The inventions of claims 1 to 9 are:
Prior to reading the original image, correction data for optically scanning a reference member placed directly above the reading position to convert the reflected light into an image signal and correcting the image signal for shading distortion caused by the optical system. And a shading distortion correction for correcting the shading distortion of the image signal based on the correction data after the original is optically scanned to convert the reflected light into an image signal when reading the image of the original. In the image reading apparatus including the means, each of the following means is provided in order to achieve the above object.

According to the invention of claim 1, there is provided a reflected light amount variable control means for variably controlling the amount of reflected light from the reference member. According to a second aspect of the invention, in the image reading apparatus according to the first aspect, the reflected light amount variable control means is provided with a means for controlling the reflected light amount from the reference member to a predetermined level or less after the start of reading the original image. .

According to a third aspect of the present invention, in the image reading apparatus according to the first aspect, the reflected light amount variable control means variably controls the reflected light amount from the reference member at the time of collecting the correction data according to the background density of the original. It is equipped with. According to a fourth aspect of the invention, in the image reading apparatus according to the first aspect, the reflected light amount variable control means measures the transmitted light amount of the original document immediately after the reading of the original image, and the reflectance of the reference member according to the transmitted light amount. Is a means for controlling.

According to a fifth aspect of the present invention, as the reference member, a first reference member having a reflectance substantially equal to that of a standard white original,
And a second reference member having a reflectance sufficiently lower than that of the reference member. According to a sixth aspect of the present invention, in the image reading apparatus according to the fifth aspect, the first reference member is moved when the correction data is collected, and the second reference member is moved and arranged immediately above the reading position when the original image is read. A member selection moving means is provided.

According to a seventh aspect of the present invention, in the image reading apparatus according to the fifth aspect, the first reference member is fixedly arranged immediately above the reading position, and the second reference member is the first reference member when the original image is read.
The second reference member moving means is provided so as to be moved and arranged immediately above the reading position so as to overlap the optical scanning surface of the reference member. According to an eighth aspect of the invention, in the image reading apparatus according to the sixth or seventh aspect, a plurality of types of second reference members are provided corresponding to a plurality of document sizes.

According to a ninth aspect of the present invention, a light blocking member for blocking the optical path is disposed in the reading optical path near the reference member.

[0014]

According to the image reading apparatus of the present invention,
Since the reflected light amount variable control means variably controls the reflected light amount from the reference member, even a thin original such as a slip can read and process the image well, and the reproducibility of the image is not impaired. .

If the reflected light amount variable control means controls the reflected light amount from the reference member to a predetermined level or less after the reading of the original image, the reflected light from the reference member when reading the thin original image is superimposed. It is possible to prevent deterioration of image quality due to. Further, if the reflected light amount variable control means variably controls the reflected light amount from the reference member at the time of collecting the correction data in accordance with the background density of the document, the optimum correction data can be collected according to the background density of various documents. .

Alternatively, the reflected light amount variable control means measures the transmitted light amount of the original document immediately after starting reading the image of the original document, and controls the reflectance of the reference member according to the transmitted light amount to reflect the reflected light from the reference member. The reduction of light and the white background processing of the area outside the original can be favorably performed according to the type of the original.

In the image reading apparatus according to the present invention, as the reference member, the first reference member having a reflectance substantially equal to that of the standard white original and the second reference member having a reflectance sufficiently lower than that of the reference member. Since any one of the reference members is selectively placed immediately above the reading position of the original image, excellent image reading can be performed on various originals.

It should be noted that when the correction data is collected, the first reference member is moved and the second reference member is moved immediately above the reading position when the original image is read, so that the thin original image is read. It is possible to prevent image quality deterioration due to superposition of reflected light from the reference member.

Alternatively, the first reference member is fixedly arranged immediately above the reading position, and the second reference member is moved right above the reading position so as to overlap the optical scanning surface of the first reference member when reading the original image. Even if they are arranged, it is possible to prevent image quality deterioration due to superposition of reflected light from the reference member when reading a thin original image. Further, by providing a plurality of types of second reference members corresponding to a plurality of document sizes, a good image can be read according to the document size.

In the image reading apparatus according to the invention of claim 9,
Since a light blocking member that blocks the optical path is arranged in the middle of the reading optical path near the reference member, unnecessary reflected light from the reference member can be blocked, and good image reading can be performed on various originals. .

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a block diagram showing an example of the configuration of a facsimile apparatus according to the first embodiment of the present invention, which includes a system controller 1, a system memory 2, a parameter memory 3, a scanner 4, a plotter 5, an operation panel 6, and an encoding / decoding device. The conversion unit 7, the image storage device 8, the modem 9, and the network control device (network control unit) 10 are included.

The system control unit 1 is a central processing unit that performs control processing of each unit of the apparatus and facsimile transmission control procedure processing. The system memory 2 stores a control processing program and various data for causing the system control unit 1 to perform various control processes, and is used as a work area used when the system control unit 1 performs various control processes.

The parameter memory 3 is a memory for storing various information unique to the G3 facsimile apparatus. The scanner 4 optically scans a document with an optical system, projects a document image based on the reflected light on an image sensor, and converts it into an image signal by photoelectric conversion, thereby reading the document image at a predetermined resolution and converting the image signal into the image signal. On the other hand, various image processing is performed.

The plotter unit 5 records the image signal image-processed by the scanner 4 or the image signal received from another facsimile apparatus on paper at a predetermined resolution. The operation panel 6 is
It is used to operate this facsimile apparatus, and comprises various operation keys and various display devices.

The encoding / decoding unit 7 encodes and compresses the image signal, and also decodes the encoded and compressed image information (image signal) into the original image signal. The image storage device 8 stores the image information that is coded and compressed by the coding / decoding unit 7.

The modem 9 is for realizing the modem function of the G3 facsimile apparatus, and is a low-speed modem function (V.21 modem) for exchanging transmission procedure signals and a high-speed modem mainly for exchanging image information. Function (V29
Modem, V.I. 27ter modem). The network control device 10 is for connecting the facsimile device to a public circuit, and has an automatic transmission / reception function.

These system control unit 1, system memory 2, parameter memory 3, scanner 4, plotter 5,
The operation panel 6, the encoding / decoding unit 7, the image storage device 8, the modem 9, and the network control device 10 are connected to a system bus 11, and the exchange of data among these respective elements is mainly performed by the system bus 11. Done through. Also, data is exchanged directly between the network control device 10 and the modem 9.

Before describing the scanner 4 according to the present invention, a general scanner will be described in order to make it easy to understand. FIG. 3 is a configuration diagram showing an example of a main part of a general scanner.

In FIG. 3, numeral 12 is a document to be read,
Reference numeral 13 is a target glass that guides the conveyance of the original 12 and prevents dust and the like from entering the optical system, 14 is a light source that illuminates the original 12, and 15 is a reference member (refer to a reference member for correcting shading distortion caused by the optical system). A white reference member having a reflectance substantially equal to that of a standard white original), 16 is a mirror for guiding the reflected light from the original 12 or the reference member 15 by a predetermined optical path length, 1
Reference numeral 7 is a lens for forming the document image guided by the mirror 16 at a predetermined reduction ratio.

Further, 18 is an image sensor for photoelectrically converting the optical information formed by the lens 17 into an analog image signal (electrical signal), and 19 is an operational amplifier for amplifying the analog image signal from the image sensor 18 at a predetermined magnification. (Hereinafter referred to as “op amp”), 20 is a peak detector that detects and holds the maximum value (peak level) of the image signal for one line amplified by the op amp 19, and 21 is the peak detector 20.
Is an A / D conversion unit that quantizes an image signal based on the peak level held by.

Further, 22 is a shading distortion correction section for correcting the shading distortion caused by the characteristics of the optical system with respect to the image signal quantized by the A / D conversion section 21, and 23.
Is a digital image processing unit for performing various image processing on the image signal from which the distortion is removed by the shading distortion correction unit 22, and 24 is a line for storing various data referred to by the shading distortion correction unit 22 and the digital image processing unit 23. It is a buffer.

Prior to reading the original image, a system controller (not shown) turns on the light source 14. The irradiation light from the light source 14 passes through the target glass 13 and the reference member 15
To reach. Then, a part of the irradiation light is reflected according to the reflectance of the reference member 15, and a part is transmitted (absorbed).

The reflected light is classified into two types, specular reflection light and irregular reflection light. Of these, a part of the irregular reflection light is reflected by the mirror 16.
Light is guided through the lens 17 and is imaged on the light receiving surface of the image sensor 18 by the lens 17. The output of the image sensor 18 at this time is quantized by the A / D converter 21, and is collected and stored in the line buffer 24 as correction data (white reference data) for correcting shading distortion caused by the optical system.

At the time of reading the original image, since the original 12 enters the optical path, the irradiation light is reflected / transmitted by the original surface, and its diffused reflection component is similarly formed on the light receiving surface of the image sensor 18. At that time, the shading distortion correction unit 22
Reads the previously stored correction data for each corresponding pixel and performs a predetermined distortion correction calculation. The image signal after the distortion correction calculation is input to the digital image processing unit 23, and various image processing is performed.

Of the irradiation light, the light that has passed through the original 12 is reflected by the reference member 15 and is incident again from the back surface of the original 12,
A part of the light passes through the original 12 and is superimposed on the regular diffused light to form an image on the image sensor 18. After passing through the original 12, the light amount component mixed again on the optical path is a kind of flare light, which deteriorates the reproducibility of the character portion.

In a normal document, the ratio of the amount of transmitted light is small, which does not reach the level of image deterioration. However, in the case of an original having a thin paper quality such as a slip, the ratio of the amount of transmitted light is very large and the black level is offset, so that the binarization margin is reduced and the character image is significantly deteriorated.

FIG. 4 shows the reflected light and the transmitted light when the light source 14 illuminates the original. When the light source 14 is considered to be an ideal point light source, the light from the light source 14 is uniformly applied to the original 12, and reflection / transmission occurs at each part. Here, paying attention to the amount of light on the optical path that enters the image sensor 18, the amount of light emitted from the optical path that is reflected by the document surface and projected on the image sensor 18 is E ₁ , and is transmitted through the document surface and reflected by the reference member 15. , E ₂ is the amount of light emitted from the optical path projected on the image sensor 18.

When the amount of emitted light E ₁ reaches the surface of the original, the amount of light corresponding to its reflectance is reflected (E ₁ r). The reflected light E ₁ r is optically classified into specularly reflected light and irregularly reflected light, but here it is assumed that all are irregularly reflected on the incident optical path to the image sensor 18 for convenience. Part of the emitted light amount E ₁ is transmitted through the document surface (E ₁ t) and part of it is reflected again by the reference member 15 (E ₁ tr). Although a part of the reflected light E ₁ tr is transmitted from the back surface of the document to the front surface again, this light does not enter the image sensor 18 and is not a particular problem.

Similarly, a part of E ₂ is transmitted through the original 12 (E
₂ t), after being reflected by the reference member 15, the document surface is transmitted again (E ₂ trt) and is mixed in the incident optical path to the image sensor 18. Therefore, the total amount of light incident on the image sensor 18 is E ₁ r + E ₂ trt. Of these, the reflected light E ₁ r is the normal image information, and the reflected light E ₂ trt is the offset component. The magnitude of the reflected light E ₂ trt varies depending on the quality of the original document, but the ratio is larger for a thin original such as a slip.

FIG. 5 is a timing chart for explaining the influence of the reflected light E ₂ trt on the image signal. Assuming that the binarization threshold TH of the image signal is 50% of the peak level, in the example in which only the component of the reflected light E ₁ r is incident as shown in (a) of FIG. 5, three black portions are binarized. Although it is also reproduced, in the example in which the reflected light E ₂ trt from the reference member 15 is superimposed as shown in (b), this becomes an offset component and the central black portion is missing after binarization.

As is apparent from FIG. 5, the region that is likely to be missing is likely to be an area in which the input image signal level does not completely drop to the black level, that is, a thin line, a line image, or the like. Therefore, the reproducibility of letters, ruled lines, and the like on slips and the like, which are thin in paper quality and have high transmittance, is greatly deteriorated. To prevent this deterioration of image quality, E ₂ t
It is necessary to reduce the rt component, that is, the reflected light from the reference member 15 as much as possible.

FIG. 1 is a block diagram showing an example of a main part of the scanner 4 according to the present invention shown in FIG. 2, and parts corresponding to those in FIG. 3 are designated by the same reference numerals. Although a circuit for processing an image signal output from the image sensor 18 is not shown in FIG. 1 and FIGS. 8, 10, 13, 16, and 19 described later, the circuit in the scanner 4 is not shown. Since the configuration is the same as that shown in FIG. 3, it will be used in the following description.

In FIG. 1, reference numeral 25 is a reflected light amount control unit for variably controlling the amount of reflected light from the reference member 15, and 26 is the original document 1.
Document density sensor (DS) 2 for detecting background density, which is composed of, for example, a reflection type photo sensor. The reflected light amount control unit 25 and the document density sensor 26 are both controlled by the system control unit 1 of FIG.

When the start of reading the original image is instructed,
The system controller 1 turns on the light source 14 at a predetermined timing and conveys the original 12 to the reading position (scan line).

Normally, as described above, the reflected light from the reference member 15 is converted into an image signal by the image sensor 18 before the original 12 reaches the scan line, and the image signal is amplified by the operational amplifier 19 (see FIG. 3). Rear A / D
Since it is quantized by the conversion unit 21, it is sampled and stored in the line buffer 24 as correction data (white reference data) for correcting the shading distortion caused by the optical system by the shading distortion correction unit 22.

Thereafter, when the original image is read, the optical path from the light source 14 to the reference member 15 is blocked by the original 12, and the reflected light from the original 12 is reflected by the image sensor 1.
An image is formed on the light receiving surface of 8. However, as described above, depending on the transmittance of the original document 12, a part of the illumination light may not be emitted.
Passes through and reaches the reference member 15, and the reflected light is superimposed on the regular reflected light (image information) and enters the light receiving surface of the image sensor 18. In a document such as a slip having a thin paper quality, the ratio of the superposed light is large, which deteriorates the image quality.

Therefore, in the facsimile apparatus of this embodiment, in order to improve such a technical problem, the reflected light amount control unit 25 is instructed by the system control unit 1 to scan the scanner 4.
The amount of light reflected from the optical scanning surface of the reference member 15 after the start of reading the original image by the control is controlled so as to reduce the reflected light from the reference member 15 even when reading the original image having high transmittance, thereby reducing the image quality. Prevent deterioration.

FIG. 6 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, when an instruction to start reading a document image is given, the system control unit 1 turns on the light source 14 of the scanner 4 at a predetermined timing (lamp ON), and the reflected light amount control unit 25 initializes the reflected light amount from the reference member 15. Turn into.

After that, the feeding of the original set on the original table (not shown) is started, and the correction data is sampled when the original reaches the correction data (white reference data) sampling position. That is, the reflected light from the reference member 15 is converted into an image signal by the image sensor 18, amplified by the operational amplifier 19 as described above, and then quantized by the A / D conversion unit 21. The data is collected and stored in the line buffer 24 as correction data for correcting shading distortion caused by the system.

Next, after the reflected light amount control unit 25 reduces the reflected light amount from the reference member 15 to a predetermined level or less, when the original reaches the reading start position, the image for one line is read. That is, the reflected light from the document is converted into an image signal by the image sensor 18, amplified by the operational amplifier 19, and then converted into the A / D converter 21.
Since the image signal is quantized by, the shading distortion of the image signal is corrected based on the correction data, and then various image processes are performed by the digital image processing unit 23.

When the reading of the original image (one page) is completed, it is judged whether or not the next original (page) is on the original table, and if there is, the amount of reflected light from the reference member 15 is reflected. The control unit 25 returns to the initialization process and performs the same process as described above. If not, the process ends.

As described above, according to the facsimile apparatus of this embodiment, the reflected light amount control unit 25 variably controls the amount of reflected light from the reference member 15 according to the instruction from the system control unit 1.
That is, since the amount of light reflected from the reference member 15 is controlled to a predetermined level or less after the reading of the original image is started, it is possible to prevent image quality deterioration due to superposition of the reflected light from the reference member 15 when reading a thin original image. Therefore, it is possible to satisfactorily read and process images of various originals including thin originals such as slips, and the reproducibility of the images is not impaired.

Next, a second embodiment of the present invention will be described. Since the hardware configuration of this embodiment is the same as that of the first embodiment described above, each drawing will be referred to again. Here, the reflectance of the normal reference member (white reference member) is set to a reflectance substantially equal to that of the standard white original, but the degree of shading distortion is slightly different depending on the amount of light. It is preferable to collect under substantially equal conditions.

FIG. 7 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, the system control unit 1 sets the reflected light amount control unit 25 to the lower limit level Etr0 of the amount of light reflected by the reference member 15,
When it is instructed to start reading the original image, the scanner 4
The light source 14 is turned on (lamp ON) at a predetermined timing.

After that, feeding of the original set on the original table is started, and when the original reaches the original density measuring position (at this time, the original has not reached the scan line), the original is set. The background density is measured by a document density sensor 26 provided on the side of the document carrying-in side before reaching the scan line, and the measured value Dn is set as a preset document density determination threshold T
Compare with H.

Then, according to the comparison result, the reference member 1
The amount of reflected light from 5 is variably controlled. That is, Dn <T
If H, the lower limit level Etr0 is set as the reflected light amount level Etr from the reference member 15, and if Dn ≧ TH, the measured value D is set as the reflected light amount level Etr from the reference member 15.
After the level f (Dn) corresponding to n is set, the amount of reflected light from the reference member 15 is controlled to be substantially equal to the set light amount level Etr (the amount of reflected light from the background of the document).

Thereafter, when the document reaches the correction data (white reference data) sampling position, the correction data is sampled and stored in the line buffer 24 as described above, and when the document reaches the reading start position, it is as described above. Then, the image for that one line is read, and when the reading for one page is completed, it is judged whether or not there is the next document (page) on the document table, and if there is, the feeding of the next document is started. Then, the same processing as described above is performed, and if not, the processing ends.

As described above, according to the facsimile apparatus of this embodiment, the reflected light amount control unit 25 is instructed by the system control unit 1 in the same manner as in the first embodiment, and the reference member 15 is operated.
The variable amount of reflected light from the reference member 15, that is, the variable amount of reflected light from the reference member 15 at the time of collecting the correction data is variably controlled according to the background density of the document, so that the optimum correction data can be collected according to the background density of various documents. it can. In addition, the reference member 15
Since a predetermined lower limit level is set for the amount of reflected light from, the image quality is not lost even when reading a high-density original image. Therefore, images of various originals can be read well and processed, and reproducibility of the images is not impaired.

Next explained is the third embodiment of the invention. The hardware structure of this embodiment is the same as that of the first embodiment except for the scanner, and the drawings other than FIG. 1 will be referred to again. FIG. 8 shows the scanner 4 in this embodiment.
2 is a configuration diagram showing an example of a main part of FIG. 1, and parts corresponding to those in FIG.

In FIG. 8, reference numeral 27 denotes a second reference having a reflectance sufficiently lower than that of the reference member 15 (having a reflectance substantially equal to that of a standard white original, and hereinafter also referred to as "first reference member"). The reference numeral 28 denotes a reference member selection moving means (hereinafter simply referred to as a reference member selection moving means composed of a rotating means such as a motor for arranging either the first reference member 15 or the second reference member 27 immediately above the reading position of the original image. Reference numeral 29 denotes a housing which is located in the vicinity of each of the reference members 15 and 27 and is composed of a low reflectance member.

FIG. 9 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, when the reading start of the original image is instructed, the system control unit 1 turns on the light source 14 of the scanner 4 at a predetermined timing (lamp ON), and then the moving unit 28 sets the first reference member 15 to the reading position. Place it by moving it directly above.

Thereafter, the feeding of the original set on the original table is started, and the correction data is collected when the original reaches the correction data (white reference data) collection position. That is, the reflected light from the first reference member 15 is incident on the light receiving surface of the image sensor 18, and the image sensor 1 at that time is reflected.
The quantized image signal is obtained by performing the above-described processes on the output of 8 and is collected and stored in the line buffer 24 as correction data (white reference data).

After the correction data is collected, the second reference member 27 is moved and arranged by the moving means 28 right above the reading position, and when the original reaches the reading starting position, one line of the original is read as described above. The next document (page) is read on the platen when the image is read and one page has been read.
It is determined whether or not there is, and if there is, the moving means 28 first
The reference member 15 is again moved to the position immediately above the reading position and disposed, and the same processing as described above is performed. If not, the processing ends.

As described above, according to the facsimile apparatus of this embodiment, the first reference member 15 having a reflectance substantially equal to that of the standard white original and the second reference member 15 having a reflectance sufficiently lower than that of the reference member 15. A reference member 27 is provided, and when the correction data is collected, the first reference member 15 is moved and the second reference member 27 is moved right above the reading position when the original image is read. Even when reading an image of a document having a high rate, reflected light from the reference member is not superposed, and the image quality is not impaired. Therefore, good image reading can be performed on various originals.

In the facsimile apparatus of this embodiment, since the housing 29 located near each of the reference members 15 and 27 is made of a low reflectance member, the second reference member 27 is used.
Even if the first reference member 15 is not moved from the optical path at the time of reading the original image, the second reference member 27 is not provided because the reflection of the light transmitted through the original does not occur even if is not moved right above the reading position (optical path). However, the same effect as described above can be expected.

Next, a fourth embodiment of the present invention will be described. The hardware structure of this embodiment is the same as that of the first embodiment except for the scanner, and the drawings other than FIG. 1 will be referred to again.

FIG. 10 shows the scanner 4 in this embodiment.
FIG. 9 is a configuration diagram showing an example of the main part of FIG. In FIG. 10, reference numeral 30 denotes a document size detection unit using a photo sensor, which detects the document size (document width). Although illustration is omitted,
It is assumed that a plurality of types of second reference members 27 are provided in correspondence with a plurality of document sizes (document widths).

FIG. 11 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, when the reading start of the original image is instructed, the system control unit 1 turns on the light source 14 of the scanner 4 at a predetermined timing (lamp ON), and then the moving unit 28 moves the second reference member 27 to the reading position. Evacuate from directly above (on the optical path).

Then, the feeding of the original is started from the original table, and the width thereof is detected by the original size detecting section 30,
When the document reaches the correction data (white reference data) collection position, the correction data is collected. That is, the reflected light from the first reference member 15 fixedly arranged immediately above the reading position is incident on the light receiving surface of the image sensor 18, and the output of the image sensor 18 at that time is subjected to each processing as in the above-described embodiment. Since the image signal that has been subjected to quantization is obtained, it is collected and stored in the line buffer 24 as correction data (white reference data).

After the correction data is collected, a plurality of types of second reference members 27 having a width corresponding to (substantially matching) the document width detected by the document size detection unit 30 are selected and moved. By means 28, the first reference member 15 is moved and arranged right above the reading position so as to overlap with the optical scanning surface of the first reference member 15.

Then, when the original reaches the reading start position, the image for one line is read in the same manner as in the above-mentioned embodiment, and when the reading for one page is completed, the next original (page) is placed on the original table. It is determined whether or not there is, and if there is, the moving means 28 retracts the second reference member 27 from immediately above the reading position, and thereafter the same processing as described above is performed. If not, the processing ends.

Here, as shown in FIG.
When the reference member 27 of is arranged in the entire reading position,
When reading an image of a document that is less than the effective reading width, scumming may occur in the area outside the document. Therefore, the document width is detected by the document size detection unit 30, and as shown in FIG. 7B, one of the second reference members 27 corresponding to the detected width is arranged immediately above the reading position and placed outside the document. Allows areas to be white background processed.

As described above, according to the facsimile apparatus of this embodiment, the first reference member 15 is fixedly arranged immediately above the reading position, and the second reference member 2 is read at the time of reading the original image.
Of the seven, the one corresponding to the document width is firstly moved by the moving means 28.
Since the reference member 15 is moved and arranged immediately above the reading position so as to overlap with the optical scanning surface of the reference member 15, the reflected light from the reference member is superposed even when reading the image of the original having high transmittance as in the above-described embodiment. In addition, the area outside the original can be processed on a white background. Therefore, good image reading can be performed on documents of various paper qualities and sizes.

Next explained is the fifth embodiment of the invention. The hardware structure of this embodiment is the same as that of the first embodiment except for the scanner, and the drawings other than FIG. 1 will be referred to again. FIG. 13 is a configuration diagram showing an example of a main part of the scanner 4 in this embodiment, and parts corresponding to those in FIG. 10 are designated by the same reference numerals.

In FIG. 13, reference numeral 31 denotes a liquid crystal shutter array that transmits / blocks incident light using a light blocking member that blocks the optical path, and is arranged in the vicinity of the reference member 15 in the reading optical path. A liquid crystal shutter control unit 32 arbitrarily controls transmission / shielding of incident light by the liquid crystal shutter array 31 according to an instruction from the system control unit 1.

FIG. 14 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, when the start of reading the original image is instructed, the system control unit 1 turns on the light source 14 of the scanner 4 at a predetermined timing (lamp ON), and then the liquid crystal shutter control unit 32 transmits the entire light through the liquid crystal shutter array 31. Put in a state.

After that, the feeding of the original is started from the original table and the width thereof is detected by the original size detecting section 30,
When the document reaches the correction data (white reference data) collection position, the correction data is collected. That is, the illumination light transmitted through the liquid crystal shutter 31 is reflected by the first reference member 15, is transmitted through the liquid crystal shutter array 31 again, and is focused on the light receiving surface of the image sensor 18. Similarly, each processing is performed to obtain a quantized image signal, which is collected and stored in the line buffer 24 as correction data (white reference data).

After that, the liquid crystal shutter control unit 32 causes the area corresponding to the document width (detection width) in the liquid crystal shutter array 31 to be in a light-shielded state, and when the document reaches the reading start position, the same as in the above-described embodiment. When the image for one line is read, and when the reading for one page is completed, it is determined whether or not there is a next document (page) on the platen. After that, the same processing as described above is performed thereafter, and if not, the processing ends.

As described above, according to the facsimile apparatus of this embodiment, since the liquid crystal shutter array 31 using the light blocking member for blocking the optical path is arranged in the middle of the reading optical path near the reference member 15, as shown in FIG. At the time of reading a document image, the liquid crystal shutter 31 blocks the document transmission component of the illumination light from the light source 14 to block the reference member 1.
5, the white background processing can be performed only on the outside (transparent) area of the document. Therefore, good image reading can be performed on various originals.

The liquid crystal shutter array 31 may be arranged independently of the reference member 15. However, in this embodiment, the reference member 15 is attached to one surface of the liquid crystal shutter array 31 so as to be integrally formed. Can be reduced, and miniaturization of equipment and improvement of reliability can be expected.

Next explained is the sixth embodiment of the invention. The hardware structure of this embodiment is the same as that of the first embodiment except for the scanner, and the drawings other than FIG. 1 will be referred to again. FIG. 16 is a configuration diagram showing an example of a main part of the scanner 4 in this embodiment, and portions corresponding to those in FIG. 13 are designated by the same reference numerals.

In FIG. 16, reference numeral 33 denotes a transmitted light amount detecting section using a photosensor including a light emitting element 33a such as an LED and a light receiving element 33b such as a phototransistor for receiving light from the light emitting element 33a. The transmitted light amount of illumination light is detected.

FIG. 17 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, the system control unit 1 sets the transmittance determination threshold TH,
When it is instructed to start reading the original image, the scanner 4
The light source 14 is turned on (the lamp is turned on) at a predetermined timing, and the document feeding from the document table is started.

Next, the transmittance Et of the original is measured by using the transmitted light amount detector 33. Here, the system control unit 1 controls the transmitted light amount detection unit 3 when a document is set on the document table.
The light emitting element 33a of No. 3 is turned on, and the light receiving element 33 at that time is turned on.
The output level (amount of transmitted light) of b is stored as an initial value, and when the document interrupts the optical path between the light emitting element 33b and the light receiving element 33b, the output level of the light receiving element 33b is measured, and the measured value is used as the initial value. The transmittance of the original is calculated (measured) by the ratio of.

When the measurement of the transmittance Et of the original is completed, the transmittance Et is compared with the transmittance determination threshold value TH, and Et>
If it is TH, warning information (for example, “the image quality may be deteriorated by the superimposed light from the reference member may be deteriorated.”) Is displayed on the display of the operation panel 6 shown in FIG. , Et ≦ TH, when the document reaches the correction data (white reference data) collection position, the correction data is sampled in the same manner as in the above-described embodiments.

After that, when the original reaches the reading start position, the image for one line is read in the same manner as in the above-described embodiments, and when the reading for one page is completed, the next original (page) is placed on the original table. It is determined whether or not there is, and if there is, the feeding of the next original is started, and thereafter the same processing as described above is performed, and if not, the processing ends.

As described above, according to the facsimile apparatus of this embodiment, the system controller 1 measures the transmittance of the document using the transmitted light amount detector 33 before reading the document image, and the transmittance is predetermined. Operation panel 6 when above level
The warning information to that effect is displayed on the display unit to notify the operator, so that the operator can confirm the quality of the read image by performing a copying operation or the like in advance by the warning. Note that the warning may be a recommendation to use a carrier sheet for applying a paper to the document.

Next explained is the seventh embodiment of the invention. The hardware configuration of this embodiment is exactly the same as that of the sixth embodiment described above except that the same hardware configuration as the reflected light amount control unit 25 shown in FIG. 1 is newly added.

FIG. 18 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, when an instruction to start reading a document image is given, the system control unit 1 turns on the light source 14 of the scanner 4 at a predetermined timing (lamp ON) and starts feeding the document from the document table.

Next, the transmitted light amount detecting section 33 measures the transmitted light amount of the original. That is, the fed document is the light emitting element 33b and the light receiving element 33b of the transmitted light amount detecting section 33.
The output level (amount of transmitted light) of the light receiving element 33b is measured when the optical path between and is blocked. Then, the amount of reflected light (reflectance) from the reference member 15 is controlled according to the amount of transmitted light, and when the original reaches the correction data (white reference data) sampling position, the correction data is obtained in the same manner as in the above-described respective embodiments. Collect.

After that, when the original reaches the reading start position, the image for one line is read in the same manner as in the above-described embodiments, and when the reading for one page is completed, the next original (page) is placed on the original table. It is determined whether or not there is, and if there is, the feeding of the next original is started and thereafter the same processing as described above is performed, and if not, the processing ends.

As described above, according to the facsimile apparatus of this embodiment, the system control unit 1 measures the transmitted light amount of the document using the transmitted light amount detection unit 33 immediately after the start of reading the document image, and measures the transmitted light amount according to the transmitted light amount. Since the reflectance of the reference member 15 is controlled by the above, it is possible to collect good correction data (white reference data) and read the original image according to the original density.

Next explained is the eighth embodiment of the invention. The hardware structure of this embodiment is the same as that of the first embodiment except for the scanner, and the drawings other than FIG. 1 will be referred to again.

FIG. 19 shows the scanner 4 in this embodiment.
2 is a configuration diagram showing an example of a main part of FIG. 1, and parts corresponding to those in FIG. In FIG. 19, reference numeral 34 is a light amount sensor for detecting the amount of light incident on the optical scanning surface of the reference member 15.

FIG. 20 is a flow chart showing the image reading process in the facsimile apparatus of this embodiment. First, when an instruction to start reading a document image is given, the system controller 1 turns on the light source 14 of the scanner 4 at a predetermined timing (lamp ON), and causes the light amount sensor 34 to enter the light scanning surface of the reference member 15. Light intensity (light source 14
(Illumination light level from) and store it as an initial value.

Thereafter, the feeding of the original is started from the original table, and when the original reaches the correction data (white reference data) sampling position, the correction data is sampled in the same manner as in each of the above-described embodiments, and the original is recorded. When the reading position is reached and the optical path is blocked (when the document is carried in), the light amount sensor 34 measures the amount of light incident on the optical scanning surface of the reference member 15 (the amount of transmitted light from the document), and before the document is carried in. The transmittance of the document is calculated based on the ratio to the incident light amount (initial value), and the reflected light amount control unit 25 controls the reflectance (reflected light amount) of the reference member 15 according to the transmittance.

When the original reaches the reading start position, the image for one line is read in the same manner as in the above-described embodiments, and when the reading for one page is completed, the next original (page ) Is present, and if there is, the amount of light incident on the optical scanning surface of the reference member 15 is measured by the light amount sensor 34, and thereafter the same processing as described above is performed. If not, the processing ends.

As described above, according to the facsimile apparatus of this embodiment, the system control unit 1 calculates the transmittance of the original document by the light amount sensor 34 from the ratio of the incident light amount before and after the original document is carried in, and the reflected light amount control unit. Since 25 controls the reflectance of the reference member 15 according to the transmittance of the document calculated by the system control unit 1, good image reading can be performed according to the document density.

The light amount sensor 34 is diverted and the light source 14 is used.
It is also possible to determine the deterioration over time, and thereby improve the maintainability of the device. The embodiment in which the present invention is applied to a facsimile apparatus has been described above, but the present invention is not limited to this, and can be applied to a multi-function peripheral equipped with a scanner such as a single image scanner or a digital copying machine.

[0100]

As described above, according to the first to fourth aspects.
According to the image reading apparatus of the present invention, since the amount of light reflected from the reference member (white reference member) is variably controlled, it is possible to satisfactorily read and process images on various originals including thin originals such as slips. There is no loss of image reproducibility. It should be noted that by controlling the amount of light reflected from the reference member to a predetermined level or less after the start of reading the original image, it is possible to prevent image quality deterioration due to superposition of the reflected light from the reference member when reading a thin original image.

Further, by variably controlling the amount of light reflected from the reference member at the time of collecting the correction data in accordance with the background density of the original, the optimum correction data can be acquired according to the background density of various originals. Alternatively, the amount of transmitted light of the original is measured immediately after the reading of the original image, and the reflectance of the reference member is controlled according to the amount of transmitted light to reduce the reflected light from the reference member and to process the white background of the area outside the original. Can be satisfactorily performed according to the type of document.

According to the image reading apparatus of the present invention, the first reference member having the reflectance substantially equal to that of the standard white original document as the reference member and the reflectance sufficiently lower than the reference member. Since the second reference member is provided, by selectively arranging any one of the second reference member and the reading position of the original image, excellent image reading can be performed on various originals.

It should be noted that by arranging the first reference member at the time of correcting data collection and moving the second reference member at the time of reading the original image, the second reference member is arranged immediately above the reading position, respectively. It is possible to prevent deterioration of image quality due to superposition of reflected light from.

Alternatively, the first reference member is fixedly arranged immediately above the reading position, and the second reference member is moved immediately above the reading position so as to overlap the optical scanning surface of the first reference member when reading the original image. Even if they are arranged, the same effect as described above can be obtained. Further, by providing a plurality of types of second reference members corresponding to a plurality of document sizes, a good image can be read according to the document size.

According to the image reading apparatus of the present invention, since the light blocking member for blocking the optical path is arranged in the middle of the reading optical path in the vicinity of the reference member, unnecessary reflection light from the reference member can be blocked. Good image reading can be performed on various originals.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a main part of the scanner of FIG.

FIG. 2 is a block diagram showing a configuration example of a facsimile apparatus according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing an example of a main part of a general scanner.

4A and 4B are explanatory diagrams showing reflected light and transmitted light when a document is illuminated by a light source in the scanner of FIG.

FIG. 5 is a timing chart for explaining the influence of the reflected light E ₂ trt on the image signal.

6 is a flowchart showing an image reading process in the facsimile apparatus of FIG.

FIG. 7 is a flowchart showing an image reading process in the second embodiment of the present invention.

FIG. 8 is a configuration diagram showing an example of a main part of a scanner according to a third embodiment of the invention.

FIG. 9 is a flowchart similarly showing the image reading process.

FIG. 10 is a configuration diagram showing an example of a main part of a scanner according to a fourth embodiment of the present invention.

FIG. 11 is a flowchart showing the image reading process of the same.

FIG. 12 is an explanatory diagram of the second reference member selection / arrangement process.

FIG. 13 is a configuration diagram showing an example of main parts of a scanner according to a fifth embodiment of the present invention.

FIG. 14 is a flowchart showing the image reading process of the same.

FIG. 15 is an explanatory diagram of the document width region light-shielding control of the liquid crystal shutter array.

FIG. 16 is a configuration diagram showing an example of a main part of a scanner according to a sixth embodiment of the present invention.

FIG. 17 is a flowchart showing the image reading process of the same.

FIG. 18 is a flowchart showing image reading processing in the seventh embodiment of the present invention.

FIG. 19 is a configuration diagram showing an example of a main part of a scanner according to an eighth embodiment of the present invention.

FIG. 20 is a flowchart showing the image reading process of the same.

[Explanation of symbols]

 1: System control unit 4: Scanner 6: Operation panel 12: Original document 13: Target glass 14: Light source 15: Reference member (first reference member) 18: Image sensor 19: Amplifier 20: Peak detection unit 21: A / D Conversion unit 22: Shading distortion correction unit 23: Digital image processing unit 24: Line buffer 25: Reflected light amount control unit 26: Document density sensor 27: Second reference member 28: Moving unit 29: Housing 30: Document size detection unit 31: Liquid crystal shutter array 32: Liquid crystal shutter control unit 33: Transmitted light amount detection unit 34: Light amount sensor

Claims (9)

[Claims] 1. Prior to reading a document image, a reference member arranged immediately above the reading position is optically scanned to convert the reflected light into an image signal, and the image signal is corrected for shading distortion caused by an optical system. For correcting the shading distortion of the image signal based on the correction data after the document is optically scanned to convert the reflected light into an image signal when reading the image of the document. An image reading apparatus including: an image reading apparatus including: a reflected light amount variable control unit that variably controls an amount of reflected light from the reference member. 2. The image reading apparatus according to claim 1,
The image reading apparatus, wherein the reflected light amount variable control means has a means for controlling the amount of reflected light from the reference member to a predetermined level or less after the reading of the original image is started. 3. The image reading device according to claim 1,
An image reading apparatus, wherein the reflected light amount variable control unit has a unit that variably controls the amount of reflected light from the reference member at the time of collecting the correction data according to the background density of the document. 4. The image reading apparatus according to claim 1,
The image reading apparatus, wherein the reflected light amount variable control unit is a unit that measures the transmitted light amount of the original document immediately after the reading of the original document image and controls the reflectance of the reference member according to the transmitted light amount. 5. Prior to reading an original image, a reference member arranged immediately above the reading position is optically scanned to convert the reflected light into an image signal, and the image signal is corrected for shading distortion caused by an optical system. For correcting the shading distortion of the image signal based on the correction data after the document is optically scanned to convert the reflected light into an image signal when reading the image of the document. In the image reading apparatus including: a first reference member having a reflectance substantially equal to that of a standard white original, and a second reference member having a reflectance sufficiently lower than that of the reference member.
And an image reference device. 6. The image reading device according to claim 5,
An image characterized by including a reference member selecting and moving means for arranging the first reference member at the time of collecting the correction data and the second reference member at the time of reading the original image by moving the second reference member directly above the reading position. Reader. 7. The image reading apparatus according to claim 5,
The first reference member is fixedly arranged immediately above the reading position,
When reading the original image, the second reference member is set to the first reference member.
2. An image reading apparatus, further comprising a second reference member moving unit which is moved and arranged immediately above the reading position so as to overlap the optical scanning surface of the reference member. 8. The image reading device according to claim 6, wherein a plurality of types of the second reference member are provided in correspondence with a plurality of document sizes. 9. Prior to reading an original image, a reference member arranged immediately above the reading position is optically scanned to convert the reflected light into an image signal, and the image signal is corrected for shading distortion caused by an optical system. For correcting the shading distortion of the image signal based on the correction data after the document is optically scanned to convert the reflected light into an image signal when reading the image of the document. An image reading apparatus comprising: a light-shielding member that blocks an optical path in the middle of the reading optical path near the reference member.