JP2000261627A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a read image from causing 'out of focus' and 'black level deformation', even if a floated part such as a file margin has a thick book cast with its face down with respect to a flat bed type scanner employing a close contact sensor. SOLUTION: An unmagnified image reading CIS control section 7 discriminates that a read image is that of a file margin of a book when a white part read output value within a prescribed range is gradually decreased in the midst of reading the image of spread pages of the book plated on an original platen and allows a CLK frequency variable section 8 to decrease the frequency of a pixel clock given to a CIS 1 and allows an image processing section 3 to increase an MTF correction coefficient as its control. When the white part read output vale within a prescribed range is gradually increased, the control section 7 discriminates that the reader reads an image at the outside of the file margin of the book, and controls the frequency of the pixel clock to the increased and the MTF correction coefficient so as to restore to the original coefficient that is a value before being increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading apparatus,
The present invention relates to a facsimile, a scanner, and a DPPC image reading device.

[0002]

2. Description of the Related Art As shown in FIGS. 31A and 31B, an image reading method used in an original reading system includes a "reduced optical reading method" using a CCD and an image forming lens. Method ((a) in the same figure) and the "1: 1 image reading method (hereinafter, referred to as
"(CIS system)") ((b) in the figure).

The former image reading apparatus using the reduced optical reading system has a structure in which a reducing lens forms an image on the surface of a CCD light receiving element, so that not only the optical path length is long and the depth of focus is deep but also the height direction. Reading variation is small.

On the other hand, in the latter image reading apparatus using the CIS method, the unit can be made thinner, but because of the structure that forms an image at the same magnification, the conjugate length is very short, and the focal depth becomes extremely shallow. Since the height direction immediately becomes dark, the reading variation is large.

FIGS. 32A and 32B are explanatory views showing the fluctuation characteristics of the read output when the white reference original is raised in the height direction in the reduced optical reading system and the CIS system, respectively. . FIGS. 33A and 33B are explanatory diagrams showing the depth of focus in the reduced optical reading system and the CIS system, respectively.

[0006] As shown in FIG. 32, a comparison is made between the fluctuation characteristics of the read output when the white reference original is raised in the height direction in the reduced optical reading system and the CIS system.
As shown in FIG. 3, comparing the two methods of depth of focus,
Since the former “reduced optical reading method” has excellent characteristics, even a three-dimensional object such as a three-dimensional object or a thick book can be read to some extent, so that the resolving power and shading of the character portion are reproduced.

[0007] However, in the latter "CIS (single-magnification image reading) system", if the target object is slightly out of the best position, the resolving power is reduced and the read output is reduced.

Therefore, when a floating document such as a binding portion of a thick book is read, as shown in FIG.
Then, "blackout" occurs and the image becomes very hard to see. In particular, "blackening" is a wasteful consumption of printing toner and the like, and can be a user's complaint.

Conventionally, an image information signal is read out in real time, and the start-up characteristic of the light source is corrected and the output is varied by changing the accumulation time and the transport speed of the motor so that the output level becomes a certain appropriate value. (For example, see Japanese Patent Application Laid-Open No. 7-107249).

[0010]

When a floating document (referred to as a "book document floating portion") such as a thick book binding portion is read by the image reading apparatus as described above, the output decreases. It is possible to level up for what you have.

However, since the reading speed is reduced to change the transport speed, and control for changing the accumulation time is required, there is a problem that a complicated configuration has to be used. In addition, there is a problem that the resolution of the output image in the floating portion of the document cannot be prevented from deteriorating because it does not correspond to the defocus.

The present invention has been made in view of the above points, and in a CIS type image reading apparatus such as a flatbed type scanner using a contact sensor, a thick book is folded down when a thick book is turned down. It is an object of the present invention to prevent the occurrence of “defocus” and “blackout” in a read image even when a floating portion occurs.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a flatbed type image reading apparatus of the same size image reading method using a contact type image sensor, which is mounted on a document table. If the read output value of the white background in the predetermined range gradually decreases during reading of the image of the spread page of the book, it is determined that the image is of the binding margin of the book, and the pixel clock of the contact type image sensor is lengthened, and M
Control is performed to increase the TF correction coefficient, and when the white background read output value within a predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the pixel clock of the contact image sensor is shortened, and An image reading control means is provided so as to control the MTF correction coefficient so as to return to the original weak coefficient.

In a flatbed type image reading apparatus of the same size image reading method using a contact type image sensor, a predetermined range of a spread page of a book placed on a platen is read. If the read output value on the white background gradually decreases, it is determined to be the image of the binding margin of the book,
When the accumulation time and the pixel clock of the contact type image sensor are lengthened, the driving speed of the transport motor is reduced, and the MTF correction coefficient is controlled to be increased. Is determined to be an image deviating from the binding margin, and the accumulation time and the pixel clock of the contact type image sensor are increased, the driving speed of the transport motor is increased, and the MTF correction coefficient is returned to the original weak coefficient. It is preferable to provide image reading control means.

Further, in an image reading apparatus of a flatbed type and a same-size image reading method using a contact type image sensor, a predetermined range of a spread page of a book placed on a document table is read during reading. If the read output value on the white background gradually decreases, it is determined that the image is the image of the binding portion of the book, and the light amount of the light source for irradiating the facing pages is set to PW.
The control is performed to increase the MTF correction coefficient and increase the MTF correction coefficient. When the white background read output value in a predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the spread page is irradiated. It is preferable to provide image reading control means for controlling the amount of light of the light source to be reduced and controlling the MTF correction coefficient to return to the original weak coefficient.

Further, in an image reading apparatus of the same size image reading method using a contact type image sensor of a flat bed type, an image of a double-page spread of a book placed on a document table is read at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image, and when the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be an image of the binding margin of the book, and the predetermined range is determined. When the read output value of the white background gradually increases, it is determined that the image is out of the binding area of the book. Control is performed to increase the pixel clock of the image sensor and to increase the MTF correction coefficient. Increase the pixel clock type image sensor, may and MTF correction coefficient provided an image reading control means for controlling so as to return to the original weak coefficient.

Further, in an image reading apparatus of a flatbed type, which uses a close contact type image sensor, and reads images at a magnification of 1: 1, an image of a double-page spread of a book placed on a document table is read at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image, and when the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be an image of the binding margin of the book, and the predetermined range is determined. When the read output value of the white background gradually increases, it is determined that the image is out of the binding area of the book. Control to increase the accumulation time and pixel clock of the image sensor, reduce the drive speed of the transport motor, and increase the MTF correction coefficient. In a portion determined to be an image deviating from the binding margin portion, the accumulation time and the pixel clock of the contact type image sensor are increased, the driving speed of the transport motor is increased, and the MTF correction coefficient is returned to the original weak coefficient. It is preferable to provide image reading control means for controlling.

Further, in an image reading apparatus of a flatbed type and an image reading apparatus of the same magnification using a contact type image sensor, an image of a two-page spread of a book placed on a document table is read at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image, and when the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be an image of the binding margin of the book, and the predetermined range is determined. If the read output value of the white background gradually increases, it is determined that the image is out of the binding portion of the book, and at the time of the book scan of the facing page, the spread is determined at the portion determined to be the image of the binding portion of the book. The light amount of the light source for irradiating the page is increased by PWM control, and M
The TF correction coefficient is controlled so as to be strengthened, and the light amount of the light source for irradiating the facing pages is reduced in a portion determined to be an image deviating from the binding portion of the book, and the MTF correction coefficient is also weak. It is preferable to provide image reading control means for performing control to return to the coefficient.

Further, in an image reading apparatus of a flatbed type and a same-size image reading method using a contact type image sensor, a predetermined range of a spread page of a book placed on a document table is read. When the white background read output value gradually decreases, it is determined that the image is the image of the binding margin of the book, the drive speed of the transport motor of the contact type image sensor is reduced, and the sum of the output values of the image for several lines is sequentially obtained. Further, the MTF correction coefficient is controlled to be increased, and when the white background read output value in the predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the driving speed of the transport motor of the contact type image sensor is reduced. And the number of lines that take the sum of the output values of the image is gradually reduced, and the MTF
It is preferable to provide image reading control means for controlling the correction coefficient to return to the original weak coefficient.

Further, in an image reading apparatus of a flatbed type and an image reading apparatus of the same size using a close contact type image sensor, a predetermined range of a spread page of a book placed on a document table is read. If the read output value on the white background gradually decreases, it is determined to be the image of the binding margin of the book,
The drive speed of the transport motor of the contact type image sensor is reduced, the duty of the reset period of the pixel clock is reduced to increase the effect of the afterimage, the sum of the output values of the image of several lines is sequentially obtained, and the MTF correction coefficient is increased. When the white background read output value in the predetermined range gradually increases, it is determined that the image is out of the binding portion of the book, and the drive speed of the transport motor of the contact image sensor is increased,
Image reading for reducing the influence of afterimages by increasing the duty of the reset period of the pixel clock, gradually reducing the number of lines for summing the output values of the image, and controlling the MTF correction coefficient to return to the original weak coefficient. Control means may be provided.

Further, in an image reading apparatus of a flatbed type and an image reading apparatus of the same magnification using a contact type image sensor, a predetermined range of a spread page of a book placed on an original platen is read. When the white background read output value gradually decreases, it is determined that the image is the image of the binding margin of the book, and the control is performed so as to increase the light amount of the light source for irradiating the spread pages and to increase the MTF correction coefficient. If the white background reading output value of the range gradually rises,
It is determined that the image is out of the binding margin of the book, and the light amount of the light source for irradiating the facing pages is reduced.
It is preferable to provide image reading control means for controlling the correction coefficient to return the original weak coefficient.

Further, in an image reading apparatus of a flatbed type, which is a unit-size image reading method using a contact type image sensor, an image of a double-page spread of a book placed on a platen is faster than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image, and when the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be an image of the binding margin of the book, and the predetermined range is determined. When the read output value of the white background gradually increases, it is determined that the image is out of the binding area of the book. The drive speed of the transport motor of the image sensor is reduced, the sum of the output values of the images of several lines is sequentially obtained, and the MTF correction coefficient is controlled to be increased. In a portion determined to be an image deviating from the binding margin, the driving speed of the transport motor of the contact type image sensor is increased, the number of lines for summing the output values of the image is gradually reduced, and the MTF correction coefficient is also reduced to the original value. It is preferable to provide image reading control means for controlling the coefficient so as to return to a weak coefficient.

Further, in a flatbed type image reading apparatus of the same size image reading method using a contact type image sensor, an image of a double-page spread of a book placed on a document table is read at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image, and when the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be an image of the binding margin of the book, and the predetermined range is determined. When the read output value of the white background gradually increases, it is determined that the image is out of the binding area of the book. The drive speed of the transport motor of the image sensor, reduce the duty of the pixel clock reset period to increase the effect of afterimages, and output several lines of images. Control is performed so that the sum of the values is sequentially obtained and the MTF correction coefficient is strengthened. In a portion determined to be an image deviating from the binding margin of the book, the driving speed of the transport motor of the contact image sensor is increased to increase the pixel speed. Image reading control in which the duty of the clock reset period is lengthened to reduce the effects of afterimages, the number of lines for summing the output values of the image is gradually reduced, and the MTF correction coefficient is also returned to the original weak coefficient. Means may be provided.

Further, in an image reading apparatus of the same size image reading method using a contact type image sensor of a flat bed type, an image of a double-page spread of a book placed on a platen is faster than a normal reading speed. Prescan at a speed to roughly store the output distribution of the read image, and if the white background read output value in a predetermined range gradually decreases based on the output distribution, it is determined that the image is the image of the binding margin of the book. If the white background reading output value of the range gradually increases, it is determined that the image is outside the binding margin of the book,
At the time of the main scan of the facing page, in a portion determined to be an image of the binding margin portion of the book, control is performed so as to increase the amount of light of the light source irradiating the facing page and to increase the MTF correction coefficient, In a portion determined to be an image deviating from the binding portion of the book, image reading is performed by reducing the light amount of the light source for irradiating the facing pages and controlling the MTF correction coefficient to return the original weak coefficient. Control means may be provided.

[0025]

Embodiments of the present invention will be specifically described below with reference to the drawings. (1) Embodiment of Claim 1 of the Present Invention FIG. 1 is a block diagram showing a configuration of a main part of a scanner according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a main part of a scanner of the same magnification image reading system (CIS system) using a normal contact image sensor. FIG. 3 is a block diagram showing the internal configuration of the image processing unit shown in FIGS.
FIG. 4 is an explanatory diagram of a state when a double-page spread document is placed on a platen of the scanner according to the first embodiment of the present invention and a document floating portion.

FIG. 5 is a timing chart of various signals at the time of image reading in the scanner shown in FIG. FIG.
3 is a timing chart of various signals when reading a normal planar image and an image of a document floating portion in the scanner shown in FIG. 1. FIG. 7 is a flowchart showing an image reading control process in the scanner shown in FIG.

The CIS type scanner shown in FIG. 1 is a flatbed type image reading apparatus of the same magnification image reading type using a close contact type image sensor, and its basic configuration is the ordinary CIS type shown in FIG. It is the same as the scanner of the system, and includes a contact image sensor (CIS) 1, an A / D converter 2, an image processor 3, a RAM 4, and a CPU 6, and a CIS controller 7 instead of the signal controller 5. A function unit (shown by a broken line frame 9 in the figure) including a CLK frequency variable unit 8 is provided.

Further, as shown in FIG.
Comprises a dark output correction unit 10, a shading correction unit 11, a peak level detection unit 12, and an MTF correction unit 13.

In this scanner, as shown in FIG. 5, first, the analog video output signal "AVin" of the contact type image sensor (CIS) 1 is A / D converted from analog to digital by the A / D converter 2 and thereafter. The image data is transferred to the image processing unit 3, and the image processing unit 3
1i "is obtained.

The image processing section 3 corrects the obtained digital image reproduction data "V1i" with the dark output correction section 10 and the shading correction section 11 for variations of each pixel, and then outputs the corrected output data "V2i". Is output to the peak level detection unit 12 and the MTF correction unit 13, and the peak level detection unit 12 detects a peak value within a certain range in the main scanning direction.

The pixel clock cycle is varied according to the detected peak value to control the video output level. Further, the MTF correction unit 13 performs edge enhancement processing (MT
F correction) to obtain an image information signal "V3i".

When reading the background portion of the original as in the normal reading operation shown in FIG. 6, the CIS control unit 7 does not change the peak value of the video output signal "AVin". The unit 8 sets the pixel clock cycle (pixel clock CLK) to a normal setting.

On the other hand, as shown in FIG.
When reading a three-dimensional object with irregularities such as 0, that is,
When reading an image with the book facing down and lying on the platen,
6, the peak value of the video output signal “AVin” varies due to the floating document portion 21 (as indicated by an arrow in FIG. 6). To increase the pixel clock cycle (pixel clock CLK) to change the video output.

Further, when the reading of the floating document portion 21 is started, the falling of the output data "V2i" can be detected by the peak level detecting section 12, so that the pixel clock cycle (pixel clock CLK) is lengthened to prevent the level drop. I do.
At the same time, the MTF correction unit 13 increases M
By performing TF correction, output data “V3i” in which edges of a character portion or the like are emphasized is obtained.

That is, the image processing section 3, the CIS control section 7, the CLK frequency variable section 8 and the like read the image of the double-page spread of the book placed on the platen and read the white background read output value within a predetermined range. Gradually decreases, the image is determined to be the image of the binding margin of the book, the pixel clock of the contact type image sensor is lengthened, and the MTF correction coefficient is controlled so that the white background reading output value in the predetermined range gradually increases. , The image is judged to be out of the binding margin of the book, the pixel clock of the contact type image sensor is shortened, and M
The TF correction coefficient also functions as an image reading control unit so as to return to the original weak coefficient.

Next, the image reading control process of this scanner will be described with reference to the flowchart of FIG. In this image reading control processing, one line is synced in step (indicated by “S” in the figure) 1 and the process proceeds to step 2 where the output data “V2i” after dark output correction and shading correction is obtained from the read image signal of the previous line. It is also determined whether or not the output value is small. If the output value is small, the process proceeds to step 6 to lengthen the pixel clock, and proceeds to step 7 to increase the MTF correction coefficient.
Proceed to.

If the output value is not small in the determination in step 2, the process proceeds to step 3 to determine whether the output value of the output data "V2i" after dark output correction and shading correction is larger than the read image signal of the previous line. Judge, if big,
Proceed to step 8 to shorten the pixel clock, and step 9
Then, the MTF correction coefficient is reduced, and the process proceeds to step S5.

If it is determined in step 3 that the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line, the process proceeds to step 4 where M
The TF correction coefficient is set to a normal value, and the process proceeds to step S5. In step 5, it is determined whether or not the document is at the end. If not, the process returns to step 1 and repeats the above-mentioned processing.

Next, the image reading control processing will be further described. If the output data “V2i” is not different from the read output of the previous line during reading of a document (two-page spread of a book), it is determined that the document is in close contact with the contact glass on the platen. A video output with the clock cycle (pixel clock CLK) in the normal state is obtained, and normal MTF correction is performed, and the process continues to the next line.

If the output data "V2i" is smaller than the previous line, it is determined that the document is floating, that is, if the white background read output value in the predetermined range gradually decreases, the book binding margin is reduced. The image is determined to be a partial image, and the pixel clock cycle (pixel clock CLK) of the CIS 1 is sequentially lengthened in accordance with the decrease, and the correction is performed so that the parameter of the MTF correction coefficient of the image processing unit 3 is further strengthened.

Eventually, when it comes out of the floating part and reaches the part in close contact with the contact glass, it rises above the peak value of the previous line. Therefore, the pixel clock cycle (pixel clock CLK) of the CIS 1 is shortened in accordance with the rise, and the MTF correction coefficient of the image processing unit 3 is also weakened to return to a normal value (original weak value).

As described above, the output level of the image data is relatively increased by increasing the pixel clock frequency with respect to the level decrease of the floating portion of the document.
"Blur loss" can be prevented, and "out of focus" can be avoided by increasing the MTF correction coefficient, so that the image of a two-page spread original can be read with high image quality.

(2) Second Embodiment of the Present Invention FIG. 8 is a block diagram showing a configuration of a main part of a scanner according to a second embodiment of the present invention.

FIG. 9 is a timing chart for switching between the accumulated pulse interval and the scanner motor phase excitation in the scanner shown in FIG. FIG. 10 is a flowchart showing an image reading control process in the scanner shown in FIG.

The configuration of the CIS type scanner shown in FIG. 8 is substantially the same as that of the CIS type scanner shown in FIG. 1, and includes a contact type image sensor (CIS) 1, an A / D converter 2, an image processor 3 , A RAM 4 and a CPU 6, and a functional unit (indicated by a broken line frame 31 in the figure) comprising a CIS control unit 7 and an accumulation time / CLK frequency variable unit 30 in place of the CLK frequency variable unit 8 is provided.

A scanner motor 32, which is a drive motor for scanning the contact-type image sensor 1 with respect to the document surface, and a motor control unit 33 of a control system for controlling the drive thereof (indicated by a broken line frame 34 in the figure). A functional unit is provided.

In this scanner, first, the analog video output signal “AVi” of the contact image sensor (CIS) 1
n ”is A / D-converted from analog to digital by the A / D converter 2 and then transferred to the image processor 3, which obtains digital image reproduction data“ V1i ”.

The image processing section 3 corrects the obtained digital image reproduction data "V1i" for the variation of each pixel by the dark output correction section 10 and the shading correction section 11, and then outputs the corrected output data "V2i". Is output to the peak level detection unit 12 and the MTF correction unit 13, and the peak level detection unit 12 detects a peak value within a certain range in the main scanning direction.

The pixel clock cycle is varied according to the detected peak value to control the video output level. Further, the MTF correction unit 13 performs edge enhancement processing (MT
F correction) to obtain an image information signal "V3i".

On the other hand, when reading a three-dimensional object having irregularities such as a Book original, the peak value fluctuates. Therefore, the video output is changed by increasing the accumulation time and the pixel clock cycle in accordance with the fluctuation, thereby changing the motor output. Vary the speed.

First, when reading the background of a document as in normal reading, the CIS control unit 7 does not change the peak value of the video output signal "AVin", so that the storage time and the CLK frequency are varied. The unit 30 sets the pixel clock cycle (pixel clock CLK) to a normal setting.

On the other hand, as shown in FIG.
When reading a three-dimensional object with irregularities such as 0, that is,
When reading an image with the book facing down and lying on the platen,
Since the peak value of the video output signal “AVin” fluctuates due to the floating document portion 21 (as indicated by an arrow in the figure), the CIS control unit 7 responds to the fluctuation by the accumulation time / CLK frequency variable unit 30 as in the case of reading unevenness. The video output is changed by increasing the accumulation time and the pixel clock cycle (pixel clock CLK), and the motor driving speed of the scanner motor 32 is changed by the motor control unit 33.

Further, when reading of the floating document portion 21 is started, the peak level detecting section 12 can detect the falling of the output data "V2i", so that the accumulation time and the pixel clock cycle (pixel clock CLK) are lengthened to increase the level. 9, the motor control unit 33 adjusts the motor drive speed of the scanner motor 32 to decrease in synchronization with the accumulation time as shown in FIG. At the same time, the MTF correction unit 13 applies MTF correction that is stronger than usual, thereby enhancing the output data “V3i” that emphasizes the edges of the character portion and the like.
Get.

That is, the CIS control unit 7, the accumulation time / CLK frequency variable unit 30, the image processing unit 3, the motor control unit 33, and the like operate during reading of the image of the spread page of the book placed on the platen. When the white background read output value of the predetermined range gradually decreases, it is determined that the image is the image of the binding margin of the book,
In addition to extending the accumulation time and pixel clock of the contact type image sensor, reducing the drive speed of the transport motor,
Control is performed to increase the TF correction coefficient, and when the white background read output value in a predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the accumulation time and pixel clock of the contact image sensor are increased and The function of the image reading control means for increasing the driving speed of the transport motor and controlling the MTF correction coefficient to return to the original weak coefficient.

Next, an image reading control process of this scanner will be described with reference to the flowchart of FIG. This image reading control processing is performed in step (indicated by “S” in the figure) 11 at 1
Line sync is performed, and the process proceeds to step 12 to determine whether or not the output value of the output data “V2i” after the dark output correction and the shading correction is smaller than the read image signal of the previous line. The accumulated pulse and the pixel clock are lengthened, the process proceeds to step 17 to reduce the speed of the scanner motor, the process proceeds to step 18 to increase the MTF correction coefficient, and the process proceeds to step 15.

If the output value is not small in the judgment of step 12, the process proceeds to step 13 to determine whether the output value of the output data "V2i" after the dark output correction and the shading correction is larger than the read image signal of the previous line. If it is determined that it is larger, proceed to step 19 to shorten the accumulated pulse and the pixel clock, proceed to step 20 to increase the speed of the scanner motor, proceed to step 21 to weaken the MTF correction coefficient,
Proceed to step 15.

If the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line in the judgment of the step 13, the process proceeds to a step 14, where the MTF correction coefficient is set to a normal value. Proceed to 15.

In step 15, it is determined whether or not the document is at the end. If not, the process returns to step 11 to repeat the above-described processing.

Next, the image reading control processing will be further described. If the output data “V2i” is not different from the read output of the previous line during reading of a document (two-page spread of a book), it is determined that the document is in close contact with the contact glass of the platen. Time, pixel clock cycle (pixel clock CLK) and scanner motor 3
Then, the video output becomes the video output with the driving speed of No. 2 in the normal state, and the normal MTF correction is performed, and the process continues to the next line.

When the output data "V2i" is smaller than the previous line, it is determined that the document is floating, that is, the white background read output value in the predetermined range is gradually lowered and the binding margin of the book is reduced. If it is determined that the image is an image, the accumulation time of the CIS 1 and the pixel clock cycle (pixel clock CLK) are sequentially increased in accordance with the decrease, the drive speed (drive speed) of the scanner motor 32 is reduced, and the MTF correction parameter is increased. Is corrected as follows.

Eventually, when it comes out of the floating portion and reaches a portion in close contact with the contact glass, the peak value of the previous line is increased. If it is determined that the image is out of the portion, the accumulation time of the CIS 1 and the pixel clock cycle (pixel clock CLK) are increased and shortened in accordance with the increase, and the driving speed (driving speed) of the scanner motor 32 is increased. The MTF correction coefficient of the processing unit 3 is also weakened to return to a normal value (original weak value).

As described above, when the level of the floating portion of the document is lowered, the storage time of the contact type image sensor and the pixel clock frequency are increased, and at the same time, the drive speed of the scanner motor (CIS transport motor) is reduced. Since the output level of image data rises relatively,
"Blur loss" can be prevented, and "out of focus" can be avoided by increasing the MTF correction coefficient, so that the image of a two-page spread original can be read with high image quality.

(3) Third Embodiment of the Present Invention FIG. 11 is a block diagram showing a configuration of a main part of a scanner according to a third embodiment of the present invention. FIG.
12 is a block diagram illustrating a circuit configuration of a light quantity PWM control unit in FIG. FIG. 13 is a flowchart showing an image reading control process in the scanner shown in FIG.

The basic configuration of the CIS type scanner shown in FIG. 11 is substantially the same as that of the CIS type scanner shown in FIG. 1, and includes a contact image sensor (CIS) 1, an A / D converter 2, an image processing unit A functional unit (shown by a broken line frame 41 in the figure) including a CIS control unit 7 and a light quantity PWM control unit 40 is provided. The light quantity PWM control unit 40 has a circuit configuration as shown in FIG.

As shown in FIG. 11, the A / D converter 2 converts the analog video output signal “AVin” of the contact type image sensor (CIS) 1 from analog to digital. The image data is transferred to the image processing unit 3, and the image processing unit 3
1i "is obtained.

The image processing unit 3 corrects the obtained digital image reproduction data “V1i” for variations of each pixel by the dark output correction unit 10 and the shading correction unit 11, and then outputs the corrected output data “V2i”. Is detected by the peak level detector 12 in a predetermined range in the main scanning direction.

The video output level is controlled by varying the pixel clock cycle according to the detected peak value. Further, the MTF correction unit 13 performs edge enhancement processing (MT
F correction) to obtain an image information signal "V3i".

The CIS control unit 7, when reading the background portion of the original as in the normal reading of FIG.
Since the peak value of the video output signal “AVin” does not fluctuate, the light amount PWM control unit 40 controls the light amount of the light source by setting it to a normal duty (DUTY).

On the other hand, as shown in FIG.
When reading a three-dimensional object with irregularities such as 0, that is,
When reading an image on a double-page spread with a book facing down on a platen, as in the case of reading unevenness in FIG.
The controller 7 changes the peak value of the video output signal “AVin” due to the floating document portion 21 (indicated by an arrow in the figure).
The on-duty period by the light quantity PWM control unit 40 is varied according to the variation to change the video output level up and down.

Furthermore, when the reading of the floating document portion 21 is started, the peak level detecting section 12 can detect that the output data “V2i” falls, so that the on-duty period by the light quantity PWM control section 40 is lengthened to reduce the level. To prevent. At the same time, the MTF correction unit 13 applies MTF correction that is stronger than usual, thereby obtaining output data “V3i” in which edges of character portions and the like are emphasized.

That is, the CIS control unit 7, the light amount PW
The M control unit 40 or the like determines that the image is the image of the binding margin of the book if the white background read output value within the predetermined range gradually decreases while reading the image of the facing page of the book placed on the platen. , The light amount of the light source for irradiating the above spread pages with P
The value is increased by the WM control and controlled so as to increase the MTF correction coefficient. When the white background read output value in the predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the spread page is irradiated. The function of the image reading control means is to reduce the amount of light of the light source and to control the MTF correction coefficient to return to the original weak coefficient.

Next, the image reading process of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, one line is synced in step (indicated by “S” in the figure) 31 and the process proceeds to step 32 in which the output data “V2i” after dark output correction and shading correction is obtained from the read image signal of the previous line. It is also determined whether or not the output value is small. If the output value is small, the routine proceeds to step 36, in which the on-duty period of the light source is increased to increase the amount of light, the routine proceeds to step 37, the MTF correction coefficient is increased, and the routine proceeds to step 35.

If the output value is not small in the judgment of step 32, the flow advances to step 33 to determine whether or not the output value "V2i" after the dark output correction and the shading correction is larger than the read image signal of the previous line. If it is determined to be larger, the process proceeds to step 38 to reduce the amount of light by reducing the on-duty period of the light source, and to step 39, the MTF
The correction coefficient is weakened, and the process proceeds to step S35.

If the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line in the judgment of step 33, the process proceeds to step 34, where the MTF correction coefficient is set to a normal value. Proceed to 35.

In step 35, it is determined whether or not the document is the end. If not, the process returns to step 31 to repeat the above-mentioned processing.

Next, the image reading control process will be further described. While reading a manuscript (two-page spread),
If the output data “V2i” is not different from the reading output of the previous line, it is determined that the document is in close contact with the contact glass of the document table. Duty (DU
(TY) period, a normal video output is obtained, a normal MTF correction is performed, and the process continues to the next line.

When the output data "V2i" becomes smaller than the previous line (when the white background read output value in the predetermined range gradually decreases), it is determined that the document is floating (the image of the binding margin of the book). Since the determination is made, the duty (DUTY) period of the PWM control signal is sequentially increased according to the decrease, and control is performed so as to increase the light amount of the light source of the CIS1.
In addition, the correction is performed so that the parameter of the MTF correction coefficient of the image processing unit 3 is strengthened.

Eventually, when it comes out of the floating portion and reaches the portion in close contact with the contact glass, it rises above the peak value of the previous line. Since it can be determined that the image is a substitute portion image, the duty period is reduced according to the amount of the rise, and control is performed so as to reduce the light amount of the light source of the CIS1,
The MTF correction coefficient of the image processing unit 3 is also weakened to return to a normal value (original weak value).

In this way, the output level of the image data is relatively increased by increasing the light amount of the light source by the PWM control with respect to the level decrease of the floating portion of the document, so that "blackout" is prevented. Becomes possible,
In addition, by increasing the MTF correction coefficient, "defocus"
Therefore, the image of the two-page spread original of the book can be read with high image quality.

(4) Fourth Embodiment of the Invention The configuration of the scanner of this embodiment is the same as the configuration of the scanner shown in FIGS. 1 and 3, but its processing is slightly different. FIG. 14 is a flowchart showing an image reading control process in the scanner according to the fourth embodiment of the present invention.

In this scanner, a pre-scan is executed before a main scan of a two-page spread original (two-page spread),
During the main scan, the pixel clock frequency and the MTF correction coefficient are adjusted based on the prescan result.

The CIS control unit 7 and the image processing unit 3
Before actually reading the original, pre-scanning is performed in advance to store a rough output distribution of image data of the image to be read in a memory (for example, RAM 4). At this time, since detailed image data is not required, there is no problem even if the line density is rough, and scanning may be performed at a speed several times higher than a normal scanning speed.

Then, based on the output distribution information of the image data collected in the memory, a line having a low output value is determined to be a floating portion of the original, and the pixel clock frequency and the MTF during the actual reading of the original, which is the next step, are determined. Change the setting of each parameter of the correction coefficient.

At the time of the main scan, the CIS control section 7 outputs the video output signal "AVi" based on the output distribution information when the background portion of the document is being read as in the normal reading of FIG.
Since the peak value of n ″ does not change, the CLK frequency variable unit 8 sets the pixel clock cycle (pixel clock CLK) to a normal setting.

On the other hand, as shown in FIG.
When reading a three-dimensional object with irregularities such as 0, that is,
When reading an image on a double-page spread with a book facing down on a platen, as in the case of reading unevenness in FIG.
The control unit 7 causes the CLK frequency variable unit 8 to change the peak value of the video output signal “AVin” due to the floating document portion 21 (indicated by an arrow in the figure).

Therefore, the pixel clock cycle (pixel clock CLK) is changed to be longer according to the fluctuation estimated from the distribution information, and after a series of processing, the MTF correction unit 1
3, the output data “V3i” in which the edge of the character portion or the like is emphasized by performing MTF correction stronger than usual.

That is, the CIS control unit 7, the CLK frequency variable unit 8, the image processing unit 3 and the like perform pre-scanning of an image of a double-page spread of a book placed on a document table at a speed higher than a normal reading speed. The output distribution of the read image is roughly stored, and based on the output distribution, when the white background read output value in a predetermined range gradually decreases, it is determined to be an image of a binding portion of a book, and the white background read output in a predetermined range is determined. If the value gradually increases, it is determined that the image is out of the binding margin of the book, and at the time of the main scanning of the facing pages, the part determined to be the image of the binding margin of the book has the image of the contact type image sensor. Increase pixel clock and MTF
The correction coefficient is controlled so as to be strengthened, and the pixel clock of the contact type image sensor is shortened in a portion determined to be an image deviating from the binding margin of the book, and the MTF correction coefficient is returned to the original weak coefficient. It performs the function of the image reading control means for controlling.

Next, the image reading process of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, first, as a pre-scan, the speed of the scanner motor is set to n times (n> 1) in step (indicated by "S" in the figure) 41, and the process proceeds to step 42 to execute the pre-scan. Then, the process proceeds to step 43 to determine a floating area (a floating portion of a two-page spread document). The process proceeds to step 44 to return and set the speed of the scanner motor to one-time, and then proceeds to step 45.

In step 45, one line sync is performed, and in step 46, the output data "V2i" after the dark output correction and the shading correction is output from the read image signal of the previous line based on the output distribution information at the time of prescan. It is determined whether or not is smaller. If it is smaller, the process proceeds to step 50 to increase the pixel clock frequency, the process proceeds to step 51, the MTF correction coefficient is increased, and the process proceeds to step 49.

If the output value is not small in the determination at step 46, the process proceeds to step 47, where the output data "V2i" after the dark output correction and the shading correction is read out based on the output distribution information at the time of the pre-scan and the read image signal of the previous line. It is determined whether or not the output value is larger than the threshold value.
Proceeding to 3, the MTF correction coefficient is weakened, and the process proceeds to step 49.

If it is determined in step 47 that the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line based on the output distribution information at the time of the prescan, the flow proceeds to step 48. The MTF correction coefficient is set to a normal value, and the routine proceeds to step 49. Step 4
In step 9, it is determined whether or not the original is completed. If not, the process returns to step 45 to repeat the above-described processing. If completed, the reading of the original image is terminated.

Next, the image reading control processing at the time of the main scan will be further described. When the output data “V2i” is not different from the read output of the previous line from the document output distribution information (output distribution of the read image) captured at the time of the main scan and the pre-scan, the document comes into close contact with the contact glass of the platen. Is determined to be present, only normal MTF correction is performed, and the process continues to the next line.

On the other hand, in a region where the output distribution is low (a region where the white background read output value within a predetermined range gradually decreases), the line is determined to be a floating document (image of a binding portion of a book).
The pixel clock cycle of CIS1 is lengthened, and the correction is performed so that the parameter of the MTF correction coefficient of the image processing unit 3 is further strengthened.

Eventually, in the area where the output distribution is high (the area where the white background reading output value within the predetermined range is gradually increased), the original is in close contact with the contact glass (the area outside the binding margin of the book). The pixel clock cycle of the CIS 1 is shortened in accordance with the rise, and the MTF of the image processing unit 3 is reduced.
The correction coefficient is also weakened to return to a normal value (original weak value).

(5) Embodiment 5 of the Invention The configuration of the scanner of this embodiment is the same as the configuration of the scanner shown in FIG. 8, but the processing is slightly different. FIG.
5 is a flowchart showing an image reading control process in the scanner according to the fifth embodiment of the present invention.

In this scanner, a pre-scan is executed before a main scan of a two-page spread original (two-page spread),
At the time of the main scan, the accumulation time, the pixel clock frequency, the driving speed of the scanner motor, and the MTF correction coefficient are adjusted based on the prescan result.

The CIS control unit 7 and the image processing unit 3
Before actually reading the original, pre-scanning is performed in advance to store a rough output distribution of image data of the image to be read in a memory (for example, RAM 4). At this time, since detailed image data is not required, there is no problem even if the line density is rough, and scanning may be performed at a speed several times higher than a normal scanning speed.

Then, based on the output distribution information of the image data collected in the memory, the line having a low output value is determined to be a floating portion of the document, and the next step, the accumulation time and the image clock during the actual document reading, is performed. Change the setting of each parameter of the frequency and the driving speed of the scanner motor.

At the time of the main scan, the CIS control section 7 sets the peak of the video output signal "AVin" based on the output distribution information at the time of the pre-scan, when reading the background of the document as in the normal reading. Since the value does not change, the accumulation time and the pixel clock cycle (pixel clock CLK) are fixed by the accumulation time / CLK frequency variable unit 30, and the motor drive speed of the scanner motor 32 is fixed by the motor control unit 33.

On the other hand, as shown in FIG.
When reading a three-dimensional object with irregularities such as 0, that is,
When reading an image of a double-page spread with the book facing down on a platen, the CIS control unit 7 controls the accumulation time / CLK frequency variable unit 30 and the floating document portion 21 to output the video output signal “AVin” as in the case of reading unevenness. Fluctuates (indicated by an arrow in the figure).

Therefore, the video output is changed by increasing the accumulation time and the pixel clock cycle (pixel clock CLK) according to the fluctuation estimated from the distribution information, and the motor driving speed of the scanner motor is changed. Later, MT
The output data “V” in which the edge of a character portion or the like is emphasized by applying MTF correction stronger than usual by the F correction unit 13
3i "is obtained.

That is, the CIS control unit 7, the storage time / CLK frequency variable unit 30, the image processing unit 3, the motor control unit 33, etc., read the image of the spread page of the book placed on the platen at the normal reading speed. Prescan at a faster speed than before and roughly store the output distribution of the read image, and if the read output value of the white background in a predetermined range gradually decreases based on the output distribution, determine that the image is the binding margin part of the book Then, when the white background read output value in the predetermined range gradually increases, it is determined that the image is outside the binding portion of the book, and is determined as the image of the binding portion of the book at the time of the book scan of the facing pages. In the part, the storage time of the contact type image sensor and the pixel clock are lengthened, the drive speed of the transport motor is reduced, and the MTF correction coefficient is controlled to be increased. With increasing the storage time of the contact image sensor and the pixel clock in the image and determining portion deviated from, increasing the driving speed of the conveying motor, and M
The TF correction coefficient also functions as an image reading control unit that controls to return to the original weak coefficient.

Next, the image reading process of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, first, as a pre-scan, the speed of the scanner motor is set to n times (n> 1) in step (indicated by "S" in the figure) 61, and the process proceeds to step 62 to execute the pre-scan. Then, the process proceeds to step 63 to determine a floating area (a floating portion of a two-page spread document). The process proceeds to step 64 to set the speed of the scanner motor back to 1x, and then proceeds to step 65.

In step 65, one line sync is performed, and in step 66, the output data "V2i" after the dark output correction and the shading correction is set to an output value smaller than the read image signal of the previous line based on the output distribution information at the time of prescan. It is determined whether or not is smaller, and if it is smaller, the routine proceeds to step 70, where the accumulation pulse and the pixel clock are lengthened, and
To step 72 to reduce the speed of the scanner motor.
Then, the MTF correction coefficient is increased, and the routine proceeds to step 69.

If the output value is not small in the determination at step 66, the process proceeds to step 67, where the output data “V2i” after the dark output correction and the shading correction is read out based on the output distribution information at the time of the pre-scan and the read image signal of the previous line. It is determined whether or not the output value is larger than the threshold value. If the output value is higher, the process proceeds to step 73 to shorten the accumulation pulse and the pixel clock, proceeds to step 74 to increase the speed of the scanner motor, and proceeds to step 75 to perform MTF correction. Decrease the coefficient, step 6
Proceed to step 9.

If it is determined in step 67 that the output data “V2i” after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line based on the output distribution information at the time of the prescan, the flow proceeds to step 68. The MTF correction coefficient is set to a normal value, and the routine proceeds to step 69. Step 6
In step 9, it is determined whether or not the document is finished. If not, the process returns to step 65 to repeat the above process.
If it is finished, the reading of the image of the document is ended.

Next, the image reading control processing at the time of the main scan will be further described. If the output data "V2i" is not different from the read output of the previous line at the time of the pre-scan from the document output distribution information (output distribution of the read image) captured at the time of the main scan and at the time of the pre-scan, the document is stuck on the contact glass. Is determined to be normal MTF
Performs only correction and continues to the next line.

On the other hand, in an area where the output distribution is low (an area where the white background read output value falls within a predetermined range), since the line is determined to be a floating document (image of the binding margin of a book), C
The video output is changed by increasing the accumulation time of IS1 and the pixel clock cycle, the motor drive speed of the scanner motor 32 is reduced to reduce the drive speed, and the image processing unit 3
Is corrected so that the parameter of the MTF correction coefficient is increased.

Eventually, in the area where the output distribution is high, the original is in close contact with the contact glass (the area outside the binding margin of the book).
1 and the pixel clock cycle are shortened, and the driving speed is increased by increasing the motor driving speed of the scanner motor 32, and the MTF correction coefficient of the image processing unit 3 is also weakened to return to a normal value (original weak value). To go.

(6) Embodiment 6 of the Invention The configuration of the scanner of this embodiment is the same as the configuration of the scanner shown in FIGS. 11 and 12, but the processing is slightly different. FIG. 16 is a flowchart showing an image reading control process in the scanner according to the sixth embodiment of the present invention.

In this scanner, a pre-scan is executed before a main scan of a two-page spread original, and at the time of the main scan,
Based on the prescan result, the light amount of the light source of CIS and MT
Adjust the F correction coefficient.

The CIS control unit 7 and the image processing unit 3
Before actually reading the original, pre-scanning is performed in advance to store a rough output distribution of image data of the image to be read in a memory (for example, RAM 4). At this time, since detailed image data is not required, there is no problem even if the line density is rough, and scanning may be performed at a speed several times higher than a normal scanning speed.

Then, based on the output distribution information of the image data collected in the memory, a line having a low output value is determined to be a floating portion of the original, and the light source of the CIS 1 during the actual reading of the original, which is the next step, is determined. The setting of each parameter of the light amount and the MTF correction coefficient is changed.

At the time of the main scan, the CIS control section 7 outputs the video output signal “AVin” based on the output distribution information at the time of the pre-scan and when the background portion of the document is read as in the normal reading of FIG. Since the peak value of “” does not fluctuate, a normal duty (DUT
Y) to control the light amount of the light source.

On the other hand, as shown in FIG.
When reading a three-dimensional object with irregularities such as 0, that is,
When reading an image with the book facing down and lying on the platen,
6, the peak value of the video output signal “AVin” in the CIS control unit 7 fluctuates due to the floating document portion 21 (indicated by an arrow in the drawing).

Therefore, the on-duty period of the PWM control of the light source is gradually increased by the light quantity PWM control section 40 in accordance with the fluctuation estimated from the distribution information at the time of the pre-scan. As a result, output data "V3i" in which edges such as a character portion are emphasized is obtained by performing MTF correction stronger than usual.

That is, the CIS control unit 7, the light amount PW
The M control unit 40, the image processing unit 3 and the like pre-scan the image of the facing page of the book placed on the platen at a speed higher than the normal reading speed and roughly store the output distribution of the read image. If the white background read output value in the predetermined range gradually decreases based on the output distribution, the image is determined to be an image of the binding portion of the book, and if the white background read output value in the predetermined range gradually increases, the book binding It is determined that the image is out of the portion, and at the time of the main scanning of the facing page, the light amount of the light source of the light to be irradiated on the facing page is increased by the PWM control in the portion determined to be the image of the binding portion of the book, And control to increase the MTF correction coefficient,
In a portion determined to be an image deviating from the binding margin of the book, the light amount of the light source for irradiating the above facing pages is reduced,
In addition, it functions as an image reading control unit that controls the MTF correction coefficient to return to the original weak coefficient.

Next, the image reading process of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, first, as a prescan, in step (indicated by “S” in the figure) 81, the speed of the scanner motor is set to n times (n> 1), and the process proceeds to step 82 to execute the prescan. Then, the process proceeds to step 83 to determine a floating area (a floating portion of a two-page spread document).

In step 85, one line sync is performed, and in step 86, the output data "V2i" after the dark output correction and the shading correction is output from the read image signal of the previous line based on the output distribution information at the time of prescan. It is determined whether or not is smaller. If it is smaller, the process proceeds to step 90 to increase the light amount by increasing the on-duty period of the light source, proceeds to step 91, strengthens the MTF correction coefficient, and proceeds to step 89.

If the output value is not small in the judgment at step 86, the process proceeds to step 87, where the output data "V2i" after the dark output correction and the shading correction is read based on the output distribution information at the time of the pre-scan and the read image signal of the previous line. It is determined whether or not the output value is larger than the threshold value. If the output value is higher, the process proceeds to step 92 to reduce the light amount by reducing the on-duty period of the light source, and proceeds to step 93 to weaken the MTF correction coefficient. Proceed to.

If it is determined in step 87 that the output data “V2i” after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line based on the output distribution information at the time of the prescan, the process proceeds to step 88. The MTF correction coefficient is set to a normal value, and the routine proceeds to step 89. Step 8
In step 9, it is determined whether or not the original is the end. If not, the process returns to step 85 to repeat the above-described processing.

Next, the image reading control processing at the time of the main scan will be further described. If the output data “V2i” is not different from the read output of the previous line from the document output distribution information (output distribution of the read image) captured during the main scan and the prescan, it is determined that the document is in close contact with the contact glass. Judge, perform only normal MTF correction, and continue to the next line.

On the other hand, in the area where the output distribution is low (the area where the white background read output value within the predetermined range gradually decreases), the line is determined to be a floating document (image of the binding margin of a book), and therefore the light source of the CIS1 is used. PWM control on-duty (O
(NDUTY) period is lengthened to increase the light amount of the light source, and further, the correction is performed so that the parameter of the MTF correction coefficient of the image processing unit 3 is strengthened.

Eventually, in the area where the output distribution is high (the area where the white background read output value within the predetermined range is gradually increased), the original is in close contact with the contact glass (the area of the image deviating from the binding margin of the book). , Depending on the increase
The on-duty (ONDUTY) period of S1 is shortened to reduce the amount of light applied to the facing pages, and the MTF correction coefficient of the image processing unit 3 is also weakened to return to a normal value (original weak value).

(7) Embodiment of Claim 7 of the Present Invention FIG. 17 is a block diagram showing a configuration of a main part of a scanner according to an embodiment of claim 7 of the present invention. FIG.
FIG. 18 is an explanatory diagram of an image reading operation in the scanner shown in FIG.

FIG. 19 is a timing chart of the accumulation pulse interval and the motor phase excitation switching at the time of image reading by the scanner shown in FIG. FIG. 20 is a flowchart showing an image reading control process in the scanner shown in FIG.

The CIS type scanner shown in FIG.
This is a flatbed type image reading apparatus of the same magnification image reading method using a contact type image sensor, and includes a contact type image sensor (CIS) 1, an A / D conversion unit 2, an image processing unit 3, a RAM 4, and a CPU 6. And a motor control unit 33 and a scanner motor 32 (indicated by a broken line 3 in the figure).
(Indicated by reference numeral 4).

In this scanner, first, the analog video output signal “AVi” of the contact type image sensor (CIS) 1
n ”is A / D-converted from analog to digital by the A / D converter 2 and then transferred to the image processor 3, which obtains digital image reproduction data“ V1i ”.

The image processing section 3 corrects the obtained digital image reproduction data “V1i” for the variation of each pixel by the dark output correction section 10 and the shading correction section 11, and then outputs the corrected output data “V2i”. Is output to the peak level detection unit 12 and the MTF correction unit 13, and the peak level detection unit 12 detects a peak value within a certain range in the main scanning direction.

The motor control unit 33 varies the transport motor speed of the scanner motor 32 in accordance with the detected peak value, calculates the sum of several lines, and controls the video output level. Further, edge enhancement processing (MTF correction) is performed by the MTF correction unit 13 to obtain an image information signal “V3i”.

When reading the background of the original,
Since the peak value of the video output signal “AVin” does not fluctuate, the transport motor speed and the MTF correction unit 13 are changed according to the normal accumulation pulse and the motor phase excitation switching timing in FIG. Read with normal settings.

On the other hand, a Book original 2 as shown in FIG.
When reading a three-dimensional object with irregularities such as 0, that is,
When reading an image with the book facing down and lying on the platen,
When the document floating portion (binding margin) 21 starts to be read, the peak level detector 12 can detect that the output data “V2i” has fallen. Therefore, as shown at the time of reading the fold in FIG. The drive excitation pulse period of 32 is lengthened to reduce the speed, and the sum of outputs of several lines of A / D converted image data "V1i" is sequentially obtained.

The read values for four lines during normal reading in FIG. 19: V1i (k) to V1i (k + 3),
When the speed is reduced at the time of reading the floating portion, as shown in Expression 1, the sum of the read values for four lines is output by one line by the image processing unit 3, so that the level down is prevented.

[0135]

V1i (k) ← V1i (k) + V1i (k +
1) + V1i (k + 2) + V1i (k + 3)

At the same time, the MTF correction unit 13 applies MTF correction that is stronger than usual to obtain output data “V3i” in which the edges of the character portion and the like are emphasized.

That is, if the image processing unit 3, the motor control unit 33, and the like, while reading the image of the double-page spread of the book placed on the platen, the white background read output value within the predetermined range gradually decreases. , It is determined to be the image of the binding margin of the book,
The drive speed of the conveying motor of the contact type image sensor is reduced, the output values of several lines of images are sequentially obtained, and the MTF correction coefficient is controlled so as to be increased. Then, it is determined that the image is out of the binding area of the book, the driving speed of the conveyance motor of the contact type image sensor is increased, the number of lines for summing the output values of the image is gradually reduced, and the MTF correction coefficient is increased. Also performs the function of image reading control means for controlling to return to the original weak coefficient.

Next, the image reading process of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, one line is synced in step (indicated by "S" in the figure) 101, and the process proceeds to step 102 in which the output data "V2i" after the dark output correction and the shading correction is obtained from the read image signal of the previous line. It is also determined whether or not the output value is small. If the output value is small, the routine proceeds to step 106, where the speed of the scanner motor is reduced.

Then, the process proceeds to a step 107, wherein V1i
The sum with the previous line is calculated by (k + 1) = V1i (k + 1) + V1i (k).
After increasing the correction coefficient, the process proceeds to step 105.

If the output value is not small in the determination in step 102, the flow advances to step 103 to determine whether or not the output value “V2i” after dark output correction and shading correction is larger than the read image signal of the previous line. If it is determined to be larger, the process proceeds to step 109 to increase the speed of the scanner motor, and proceeds to step 110 to obtain V1i (k + 1) =
The sum with the previous line is calculated according to V1i (k + 1) + V1i (k), the routine proceeds to step 111, the MTF correction coefficient is reduced, and the routine proceeds to step 105.

If the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line in the judgment of step 103, the process proceeds to step 104, where the MTF correction coefficient is set to a normal value. 105
Proceed to. In step 105, it is determined whether or not the document is at the end. If not, the process returns to step 101 to repeat the above-described processing.

Next, the image reading control processing will be further described. While reading a manuscript (two-page spread),
If the output data "V2i" is not different from the read output of the previous line, it is determined that the original is in close contact with the contact glass of the original platen. Is performed, and the process continues to the next line.

If the output data "V2i" becomes smaller than the previous line (the white background read output value in the predetermined range gradually decreases), it is determined that the document is floating (the image of the binding margin of the book). Therefore, the transport speed of the scanner motor 32 is sequentially reduced in accordance with the decrease, the linear density of reading is increased, the sum of the image output values of several lines is obtained, and the parameter of the MTF correction coefficient of the image processing unit 3 is calculated. Is corrected so that

When the part comes off the floating part and reaches the part which is in close contact with the contact glass, the peak read value of the previous line is increased. Since the image can be determined as an image which has been increased, the transport speed of the scanner motor 32 is increased in accordance with the increase, the number of lines to be summed is reduced, and the MTF correction coefficient of the image processing unit 3 is also reduced to a normal value (the original weak value). ).

As described above, the output level of image data is relatively increased by taking the sum of the outputs of several lines with respect to the level reduction of the floating portion of the document.
"Blur loss" can be prevented, and "out of focus" can be avoided by increasing the MTF correction coefficient, so that high-quality reading of a two-page spread original can be realized.

(8) Embodiment 8 of the Invention FIG. 21 is a block diagram showing a configuration of a main part of a scanner according to an embodiment 8 of the invention. FIG.
22 is a timing chart of various signals when an image is read by the scanner shown in FIG. 21.

FIG. 23 is a timing chart of various signals when the scanner shown in FIG. 21 reads a normal flat image and an image of a document floating portion. FIG. 24 is a flowchart showing an image reading control process in the scanner shown in FIG.

The scanner of this embodiment is different from the scanner shown in FIG. 17 in that the CIS control unit 7 and the CLK duty (Du)
ty) variable section 50 (indicated by broken line frame 51 in the figure)
A functional unit is provided.

In this scanner, first, the analog video output signal “AVi” of the contact image sensor (CIS) 1
n ”is A / D-converted from analog to digital by the A / D converter 2 and then transferred to the image processor 3, which obtains digital image reproduction data“ V1i ”.

The image processing section 3 corrects the obtained digital image reproduction data “V1i” for variations in each pixel by the dark output correction section 10 and the shading correction section 11, and then outputs the corrected output data “V2i”. Is output to the peak level detection unit 12 and the MTF correction unit 13, and the peak level detection unit 12 detects a peak value within a certain range in the main scanning direction.

According to the seventh aspect of the present invention, the reset period (H level) of the pixel clock cycle is varied according to the detected peak value so as to increase the influence of the afterimage.
In the same manner as in the scanner of the first embodiment, the sum of several lines is calculated to control the video output level. Further, edge enhancement processing (MTF correction) is performed to obtain an image information signal “V3i”.

When the background portion of the document is being read, the CIS control unit 7 reads the video output signal “AVin” with the CLK duty variable unit 50 in a normal setting because there is no change in the peak value.

On the other hand, a Book original 2 as shown in FIG.
When reading a three-dimensional object having irregularities such as 0, the output level “V2i” can be detected to decrease by the peak level detection unit 12, so that the motor control unit 33 drives and drives the scanner motor 32 according to the variation. The pulse period is lengthened to reduce the speed, the reset period of the pixel clock period is shortened in order to increase the effect of the after-image component of the previous line, and a few lines of the image information output “V1i” after A / D conversion are used. Take the sum of the outputs sequentially.

As shown in Expression 1, the effect of the afterimage caused by shortening the reset period of the pixel clock cycle and the speed is reduced to make the sum of the read values of a plurality of lines equal to one line, so that the level is lowered. Can be prevented. At the same time, the MTF correction unit 13 applies MTF correction that is stronger than usual, thereby obtaining output data “V3i” in which edges of character portions and the like are emphasized.

That is, the CIS control unit 7, the image processing unit 3, the motor control unit 33, the CLK duty variable unit 50
If the read output value of the white background in the predetermined range gradually decreases while reading the image of the double-page spread of the book placed on the platen, the image is determined to be the image of the binding margin of the book, and the contact image The drive speed of the transport motor of the sensor is reduced, the duty of the reset period of the pixel clock is reduced, the effect of the afterimage is increased, the output values of the image of several lines are sequentially summed, and the MTF correction coefficient is controlled to be increased. If the white background read output value in the predetermined range gradually increases, it is determined that the image is out of the binding area of the book, the drive speed of the transport motor of the contact image sensor is increased, and the duty of the pixel clock reset period is increased. To reduce the effect of afterimages, gradually reduce the number of lines that take the sum of the output values of the image,
In addition, it functions as an image reading control unit that controls the MTF correction coefficient to return to the original weak coefficient.

Next, the image reading process of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, one line is synced in step (indicated by “S” in the figure) 121, and the process proceeds to step 122 in which the output data “V2i” after dark output correction and shading correction is obtained from the read image signal of the previous line. It is also determined whether or not the output value is small. If the output value is small, the routine proceeds to step 124, where the speed of the scanner motor is reduced.

Then, the process proceeds to a step 125, in which the state of the H level for maintaining the RS pulse (reset of the pixel clock cycle) period is shortened.
The sum with the previous line is calculated by (k + 1) = V1i (k + 1) + V1i (k).
After increasing the correction coefficient, the process proceeds to step 129.

If the output value is not small in the judgment of step 122, the flow advances to step 123 to determine whether or not the output value "V2i" after the dark output correction and the shading correction is larger than the read image signal of the previous line. If it is determined to be larger, the process proceeds to step 130 to increase the speed of the scanner motor, the process proceeds to step 131, the state of the H level for maintaining the RS pulse (reset of the pixel clock cycle) period is increased, and the process proceeds to step 132. V1i (k + 1) =
The sum with the previous line is calculated by V1i (k + 1) + V1i (k), and the routine proceeds to step 133, where the MTF correction coefficient is weakened, and the routine proceeds to step 129.

If the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line in the determination of step 123, the process proceeds to step 128, where the MTF correction coefficient is set to a normal value. 129
Proceed to. At step 129, it is determined whether or not the document is at the end. If not, the process returns to step 121 to repeat the above-described processing.

Next, the image reading control process will be further described. While reading a manuscript (two-page spread),
If the output data “V2i” is not different from the reading output of the previous line, it is determined that the original is in close contact with the contact glass of the original platen, so that the video output is in the normal state and the normal MTF correction is performed. And continue to the next line.

When the output data "V2i" is smaller than the previous line, it is determined that the document is floating, that is, the white background read output value in the predetermined range is gradually lowered to indicate the binding margin of the book. If it is determined that the image is an image, the conveying speed of the scanner motor 32 is sequentially reduced according to the decrease, the linear density of reading is increased, the sum of image output values for several lines is obtained, and the pixel clock cycle of CIS1 is obtained. , The effect of the afterimage is increased by reducing the duty of the reset period, and the correction is performed so that the parameter of the MTF correction coefficient of the image processing unit 3 is further strengthened.

When the part comes off the floating part and reaches the part in close contact with the contact glass, the peak value of the preceding line is increased. When it is determined that the image is out of the range, the scanner motor 32
To reduce the number of lines to be summed,
Further, the duty of the reset period of the pixel clock cycle of the CIS 1 is lengthened and returned to the original value to reduce the effect of the afterimage, and the MTF correction coefficient of the image processing unit 3 is weakened and returned to the normal value.

As described above, when the reading output level of the floating portion of the document is lowered, the duty (DUTY) of the reset (H level) period of the reset pulse is varied while lowering the transport speed of the scanner motor, thereby reducing the number of lines. Since the sum of the minutes is calculated, the read output of the image data is increased, and “blackout” can be prevented. Further, M
By increasing the TF correction coefficient, "out of focus" can be avoided, so that high-quality image reading of a two-page spread original can be realized.

(9) Embodiment of Claim 9 of the Present Invention FIG. 25 is a block diagram showing a configuration of a main part of a scanner according to an embodiment of claim 9 of the present invention. FIG.
FIG. 26 is a block diagram showing a circuit configuration of a current control unit of FIG. 25 and an LED light source of CIS. FIG. 27 is a flowchart showing an image reading control process in the scanner shown in FIG.

The CIS type scanner shown in FIG.
This is a flatbed type image reading apparatus of the same magnification image reading method using a contact type image sensor, and includes a contact type image sensor (CIS) 1, an A / D conversion unit 2, an image processing unit 3, a RAM 4, and a CPU 6. And a functional unit (indicated by a broken line frame 53 in the figure) including the CIS control unit 7 and the current control unit 52 is provided. As shown in FIG. 26, the current control unit 52 includes a plurality of LED light sources 5 of the CIS 1.
4 comprises a plurality of resistors R0 to R13 for controlling the amount of current supplied to the switch 4 and switches SW11 to SW13.

As shown in FIG. 25, this scanner uses the analog video output signal “AV
in "is converted from analog to digital by the A / D converter 2 and then transferred to the image processor 3, which obtains digital image reproduction data" V1i ".

The image processing section 3 corrects the obtained digital image reproduction data "V1i" for variations of each pixel by the dark output correction section 10 and the shading correction section 11, and then outputs the corrected output data "V2i". Is detected by the peak level detector 12 within a certain range in the main scanning direction.

The light amount of the LED light source 54 is varied by the current control unit 52 in accordance with the detected peak value, and the video output level is controlled. Further, edge enhancement processing (MTF correction) is performed by the MTF correction unit 13 to obtain an image information signal “V3i”.

When reading the background portion of the document, the CIS control section 7 does not change the peak value of the video output signal “AVin”, so the CIS control section 7 controls the light amount of the LED light source 54 of the CIS 1. 52 switches SW11 to SW
13 are all set to OFF.

On the other hand, when reading a three-dimensional object having irregularities such as a Book original, the CIS control section 7 changes the peak value of the video output signal “AVin”. The video output level is changed up and down by turning on (ON) / off (OFF) sequentially.

Further, when the reading of the floating document portion is started, the output of the output data "V2i" can be detected to fall by the peak level detecting section 12, so that the current increases when each switch of the current control section 52 is turned on. As a result, the light amount of the LED light source 54 is increased, and a level reduction is prevented. At the same time, M
The TF correction unit 13 performs MTF correction that is stronger than usual, thereby obtaining output data “V3i” in which edges of character portions and the like are emphasized.

That is, while the CIS control unit 7, the image processing unit 3, the current control unit 52, and the like read an image of a double-page spread of a book placed on a document table, a white background read output value in a predetermined range is output. If it gradually decreases, it is determined that the image is the image of the binding margin of the book, the light amount of the light source for illuminating the facing pages is increased, and the MTF correction coefficient is controlled to be increased, and the white background read output value within a predetermined range is controlled. Gradually increases, it is determined that the image is out of the binding margin of the book, the light amount of the light source for illuminating the facing pages is reduced, and the MT is reduced.
The F correction coefficient also functions as an image reading control unit that controls to return the original weak coefficient.

Next, the image reading process of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, one line is synced in step (indicated by “S” in the figure) 141, and the process proceeds to step 142 in which the output data “V2i” after dark output correction and shading correction is obtained from the read image signal of the previous line. It is also determined whether or not the output value is small. If the output value is small, the process proceeds to step 146 to reduce the light source current value of the CIS by the current control unit, proceeds to step 147 to increase the MTF correction coefficient, and proceeds to step 145.

If the output value is not small in the judgment in step 142, the flow advances to step 143 to determine whether or not the output data "V2i" after the dark output correction and the shading correction has an output value larger than the read image signal of the previous line. It is determined, and if it is larger, the process proceeds to step 148, where C
The light source current value of IS is increased, and the routine proceeds to step 149, where M
The TF correction coefficient is reduced, and the process proceeds to step 145.

If the output data “V2i” after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line in the judgment of step 143, the process proceeds to step 144, where the MTF correction coefficient is set to a normal value. 145
Proceed to. In step 145, it is determined whether or not the document is at the end. If not, the process returns to step 141 to repeat the above process. If it is, the reading of the image of the document is terminated.

Next, the image reading control processing will be further described. While reading a manuscript (two-page spread),
If the output data “V2i” is not different from the read output of the previous line, it is determined that the original is in close contact with the contact glass of the original platen.
The switches SW11 to SW13 for the light amount adjustment of No. 4 are all set to OFF (OFF) to provide a normal video output, perform normal MTF correction, and continue to the next line.

If the output data "V2i" is smaller than the previous line, it is determined that the document is floating, that is, the white background read output value in the predetermined range is gradually lowered to indicate the binding margin of the book. When it is determined that the image is an image, the switches SW11 to SW1 of the current control unit 52 are sequentially switched according to the amount of the drop.
3 is turned off, the light amount of the LED light source 54 is increased, and the correction is performed so that the parameter of the MTF correction coefficient of the image processing unit 3 is further strengthened.

Eventually, when it reaches the portion that comes into close contact with the contact glass by deviating from the floating portion, it rises above the peak value of the previous line. When it is determined that the image is out of the portion, the switches SW11 to SW11 are switched according to the amount of the rise
The SW 13 is turned off (OFF) to reduce the amount of light, and the MTF correction coefficient of the image processing unit 3 is also weakened to return to the normal value.

In this way, the read output of image data is increased by increasing the illuminance of the CIS light source in response to the decrease in the read output level of the floating portion of the document.
"Blackout" can be prevented. Further, by increasing the MTF correction coefficient, "out of focus" can be avoided, so that a high-quality double-page spread original can be read.

(10) Embodiment of Claim 10 of the Invention The configuration of the scanner of this embodiment is the same as the configuration of the scanner shown in FIG. 17, but the processing is slightly different. FIG. 28 is a flowchart showing an image reading control process in the scanner according to the tenth embodiment of the present invention.

In this scanner, a pre-scan is executed before a main scan of a two-page spread original, and at the time of the main scan,
The transport speed of the scanner motor and the MTF correction coefficient are adjusted based on the prescan result.

Before the actual reading of the original by the image processing section 3, pre-scanning is performed in advance, so that a rough output distribution of image data of the image to be read is stored in a memory (for example, RAM 4). At this time, since detailed image information is not required, there is no problem even if the line density is rough, and scanning may be performed at a speed several times higher than a normal scanning speed.

Then, based on the output distribution information of the image data collected in the memory, the line having a low output value is determined to be a floating portion of the document, and the next step, ie, the transport speed of the scanner motor during the actual document reading, is performed. And the setting of each parameter of the MTF correction coefficient is changed.

At the time of the main scan, the motor control section 33 sets the transport speed of the scanner motor 32 to the normal setting because the line reading the background portion of the document has no fluctuation in the peak value of the output distribution information. The unit 3 also reads an image with the MTF correction coefficient set to a normal setting.

On the other hand, the peak value of the output distribution information fluctuates in an uneven portion such as a Book original, so that the motor control unit 33 drives the scanner motor 32 in accordance with the fluctuation estimated from the output distribution information. Decrease the transport speed by increasing the excitation pulse period.

Further, the image processing section 3 includes an A / D conversion section 2
The video output signal "V1i" of the image after analog-to-digital conversion from analog to digital is summed up for several lines of output, and after a series of processing, MTF correction stronger than usual is applied to obtain the character. The output data “V3i” in which the edges such as are emphasized is obtained.

That is, the image processing unit 3, the motor control unit 33, and the like perform pre-scanning of the image of the double-page spread of the book placed on the platen at a speed higher than the normal reading speed, and output the read image. The distribution is roughly stored, and based on the output distribution, when the white background read output value in a predetermined range gradually decreases, the image is determined to be an image of a binding margin portion of a book, and the white background read output value in a predetermined range gradually increases. If the image is determined to be out of the binding area of the book, the drive speed of the transport motor of the contact type image sensor is reduced at the part that is determined to be the image of the binding area of the book at the time of book scanning of the facing pages. The sum of the output values of the images for the lines is sequentially obtained, and the MTF correction coefficient is controlled so as to be strengthened. Feed increased driving speed of the motor, gradually reducing the number of lines to take the sum of the output values of the image, and MTF correction coefficient functions of the image reading control means for controlling so as to return to the original weak coefficient.

Next, the image reading control processing of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, first, as a pre-scan, the speed of the scanner motor is set to n times (n> 1) in step (indicated by “S” in FIG. 151), and the process proceeds to step 152 to execute the pre-scan. Then, the process proceeds to step 153 to determine a floating area (a floating portion of a two-page spread document). The process proceeds to step 154 to set the speed of the scanner motor back to 1x, and then proceeds to step 155.

In step 155, one line is synced. The flow advances to step 156 to output the output data "V2i" after the dark output correction and the shading correction to the output value of the read image signal of the previous line based on the output distribution information at the time of the prescan. It is determined whether or not is smaller.
Go to to reduce the speed of the scanner motor.

Then, the flow advances to step 161 to go to V1i.
The sum with the previous line is calculated by (k + 1) = V1i (k + 1) + V1i (k).
After increasing the correction coefficient, the process proceeds to step 159.

If the output value is not small in step 156, the flow advances to step 157 to output the output data "V2i" after the dark output correction and the shading correction to the read image signal of the previous line based on the output distribution information at the time of prescan. It is determined whether or not the output value is larger than the threshold value. If it is, the process proceeds to step 163 to increase the speed of the scanner motor, and proceeds to step 164 to obtain V1i (k + 1) = V1i (k +
1) The sum with the previous line is obtained by + V1i (k), the flow proceeds to step 165, the MTF correction coefficient is weakened, and the flow proceeds to step 159.

If it is determined in step 157 that the output data “V2i” after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line based on the output distribution information at the time of the prescan, the process proceeds to step 158. MTF
The correction coefficient is set to a normal value, and the process proceeds to step 159. In step 159, it is determined whether or not the document is at the end. If not, the process returns to step 155 to repeat the above-described process. If it is, the reading of the document image is terminated.

Next, the image reading control processing at the time of the main scan will be further described. If the output data "V2i" is not different from the read output of the previous line from the original force distribution information (output distribution of the read image) captured at the time of the main scan and the pre-scan, the original comes into close contact with the contact glass of the platen. , And only normal MTF correction is performed, and the process continues to the next line.

On the other hand, in an area where the output distribution is low, the line is determined to be a floating document, so that the white background read output value within a predetermined range gradually decreases and is determined to be an image of a binding portion of a book.
According to the descending amount estimated from the output distribution information, the transport speed of the scanner motor 32 is sequentially reduced to increase the linear density of reading, and the sum of image output values for several lines is calculated.
Further, the correction is performed by increasing the parameter of the MTF correction coefficient of the image processing unit 3.

In a region where the output distribution is high, the original is in close contact with the contact glass, so that the white background read output value in a predetermined range gradually increases and is judged to be an image deviating from the binding margin of the book. The transport speed of the scanner motor 32 is increased according to the rise estimated from the information, the number of lines to be summed is reduced, and the MTF of the image processing unit 3 is reduced.
The correction coefficient is also weakened to return to the normal value.

(11) Embodiment of Claim 11 of the Invention The configuration of the scanner of this embodiment is the same as the configuration of the scanner shown in FIG. 21, but the processing is slightly different. FIG. 29 is a flowchart showing an image reading control process in the scanner according to the eleventh embodiment of the present invention.

In this scanner, a pre-scan is executed before the main scan of a two-page spread original, and at the time of the main scan,
Based on the prescan result, the transport speed of the scanner motor 32, the duty of the reset period of the pixel clock cycle, the line sum of the image output value, and the parameters of the MTF correction coefficient are adjusted.

Before the actual reading of the original by the image processing unit 3, pre-scanning is performed in advance, so that a rough output distribution of image data of the image to be read is stored in a memory (for example, the RAM 4). At this time, since detailed image information is not required, there is no problem even if the line density is rough, and scanning may be performed at a speed several times higher than a normal scanning speed.

Based on the output distribution information of the image data collected in the memory, a line having a low output value is determined to be a floating portion of the document, and the next step, the transport speed of the scanner motor during the actual document reading, is performed. The setting of each parameter of the duty of the reset period of the pixel clock cycle, the line sum of the image output value, and the MTF correction coefficient is changed.

At the time of the main scan, the CIS control unit 7 sets the transport speed of the scanner motor 32 and the duty in the reset period of the pixel clock to the normal value because the line of the background portion of the document does not fluctuate in the peak value of the output distribution information. Then, the image processing unit 3 reads the image with the MTF correction coefficient set to the normal setting.

On the other hand, the peak value of the output distribution information fluctuates in an uneven portion such as a Book original, so that the motor control unit 33 drives the drive excitation pulse of the transport motor in accordance with the fluctuation estimated from the distribution information. To increase the cycle and reduce the speed and increase the effect of the afterimage component of the previous line,
The duty in the reset period of the pixel clock of IS1 is shortened.

Further, the image processing unit 3 includes an A / D conversion unit 2
The A / D conversion of the image from analog to digital is performed, and the sum of the outputs of several lines of the video output signal "V1i" is sequentially obtained. The output data “V3i” in which the edge of the part or the like is emphasized is obtained.

That is, the CIS control unit 7, the CLK duty variable unit 50, the image processing unit 3, and the motor control unit 33
And the like, pre-scans an image of a double-page spread of a book placed on a platen at a speed higher than a normal reading speed, roughly stores an output distribution of the read image, and determines a predetermined range based on the output distribution. If the white background read output value gradually decreases, it is determined to be the image of the binding margin of the book,
When the read output value of the white background in the predetermined range gradually increases, it is determined that the image is out of the binding portion of the book. Control to reduce the drive speed of the transport motor of the image sensor, reduce the duty of the pixel clock reset period to increase the effect of afterimages, sequentially sum the output values of images of several lines, and increase the MTF correction coefficient However, in the portion determined to be an image outside the binding portion of the book, the drive speed of the transport motor of the contact image sensor is increased, the duty of the pixel clock reset period is lengthened to reduce the effect of the afterimage, and The image reading control means functions to gradually reduce the number of lines that take the sum of the output values and to return the MTF correction coefficient to the original weak coefficient.

Next, the image reading control processing of this scanner will be described with reference to the flowchart of FIG. In this image reading control processing, first, as a pre-scan, the speed of the scanner motor is set to n times (n> 1) in step (indicated by "S" in the figure) 171 and the process proceeds to step 172 to execute the pre-scan. Then, the process proceeds to step 173 to determine a floating area (a floating portion of a two-page spread document). The process proceeds to step 174 to set the speed of the scanner motor back to 1x, and then proceeds to step 175.

At step 175, one line is synced. At step 176, it is determined whether or not the output value of the output data "V2i" after the dark output correction and the shading correction is smaller than the read image signal of the previous line. If so, proceed to step 180 to reduce the speed of the scanner motor.

Then, the process proceeds to a step 181 to shorten the state of the H level for maintaining the RS pulse (reset of the pixel clock cycle) period, so that V1i (k + 1) = V1i (k +
1) The sum with the previous line is calculated by + V1i (k), the flow proceeds to step 182, the MTF correction coefficient is increased, and the flow proceeds to step 179.

If the output value is not small in the judgment in step 176, the flow advances to step 177 to determine whether or not the output data “V2i” after the dark output correction and the shading correction has an output value larger than the read image signal of the previous line. If it is determined that it is larger, the process proceeds to step 183 to increase the speed of the scanner motor, and proceeds to step 184 to lengthen the state of the H level for maintaining the RS pulse (reset of the pixel clock cycle) period, V1i (k + 1) = V1i (k + 1) + V1
The sum with the previous line is calculated by i (k), and step 18
Proceeding to 5, the MTF correction coefficient is weakened, and the flow proceeds to step 179.

If the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line in the judgment of step 177, the flow advances to step 178 to set the MTF correction coefficient to a normal value. 179
Proceed to. In step 179, it is determined whether or not the document is at the end. If not, the process returns to step 175 to repeat the above-described process. If it is, the reading of the document image is terminated.

Next, the image reading control processing at the time of the main scan will be described. If the original output distribution information (output distribution of the read image) captured at the time of the main scan and the prescan does not differ from the read output of the previous line of the output data “V2i”, it is determined that the original is in close contact with the contact glass. Judge, perform only normal MTF correction, and continue to the next line.

On the other hand, in a region where the output distribution is low, the line is determined to be a document floating, so that a white background read output value within a predetermined range is gradually reduced and determined to be an image of a binding portion of a book.
In accordance with the descending amount estimated from the output distribution information, the transport speed of the scanner motor 32 is sequentially reduced to increase the linear density of reading, the sum of image output values of several lines is obtained, and the pixel clock reset period of CIS1 , The effect of the afterimage is increased, and the MT of the image processing unit 3 is further reduced.
The correction is performed by increasing the F correction coefficient parameter.

In the area where the output distribution is high, the original is in close contact with the contact glass, so that the white background read output value in a predetermined range gradually increases and is judged to be an image outside the binding margin of the book. The transport speed of the scanner motor 32 is increased in accordance with the rise estimated from the information, the number of lines to be summed is reduced, and the duty of the reset period of the pixel clock of the CIS1 is lengthened and returned. The correction coefficient is also weakened to return to the normal value.

(12) Embodiment 12 of the Invention The configuration of the scanner according to this embodiment is the same as the configuration of the scanner shown in FIGS. 25 and 26, but the processing is slightly different. FIG. 30 is a flowchart showing an image reading control process in the scanner according to the twelfth embodiment of the present invention.

In this scanner, prescanning is performed before main scanning of a two-page spread original, and during main scanning, the light amount of the light source of the CIS and the MTF correction coefficient are adjusted based on the prescanning result.

The CIS control unit 7 and the image processing unit 3
Before actually reading the original, pre-scanning is performed in advance to store a rough output distribution of image data of the image to be read in a memory (for example, RAM 4). At this time, since detailed image data is not required, there is no problem even if the line density is coarse, and the image may be read at a speed several times higher than a normal scan speed.

Based on the output distribution information of the image data collected in the memory, a line having a low output value is determined to be a floating portion of the document, and the light amount of the light source of the CIS 1 during the actual reading of the document, which is the next step, is determined. And MTF of image processing unit 3
Change the setting of each parameter of the correction coefficient.

At the time of the main scan, the CIS control section 7 reads the CIS1 because the peak value of the video output signal “AVin” does not fluctuate when reading the background of the document based on the distribution information at the time of the prescan. The switches SW11 to SW13 of the current control unit 52 that controls the light amount of the LED light source 54 are all set to OFF.

On the other hand, when reading a three-dimensional object having irregularities such as a Book original, the CIS control unit 7 uses the current control unit 52 to control the distribution during pre-scanning because the peak value of the video output signal “AVin” varies. The light sources SW11 to SW13 are sequentially turned on (ON) in accordance with the fluctuation estimated from the information to increase the light amount.

After a series of processing, the M
The TF correction unit 13 performs MTF correction that is stronger than usual, thereby obtaining output data “V3i” in which edges of character portions and the like are emphasized.

That is, the CIS control unit 7, the current control unit 52, the image processing unit 3 and the like perform pre-scanning of an image of a double-page spread of a book placed on a document table at a speed higher than a normal reading speed. The output distribution of the read image is roughly stored, and based on the output distribution, when the read output value of the white background in a predetermined range gradually decreases, it is determined that the image is the binding margin portion of the book, and the read output value of the white background in the predetermined range is determined. Gradually increases, it is determined that the image is out of the binding area of the book, and the light source that irradiates the facing page in the part that is determined to be the image of the binding area of the book during book scanning of the facing page By controlling the light amount to be increased and the MTF correction coefficient to be strengthened, the light amount of the light source for irradiating the facing pages is reduced in a portion determined to be an image deviating from the binding portion of the book. And MTF correction coefficient functions of the image reading control means for controlling to return the original weak coefficient.

Next, the image reading control processing of this scanner will be described with reference to the flowchart of FIG. In this image reading control process, first, as a pre-scan, the speed of the scanner motor is set to n times (n> 1) in step (indicated by “S” in the figure) 191, and the process proceeds to step 192 to execute the pre-scan. Then, the process proceeds to step 193 to determine a floating area (a floating portion of a two-page spread document). The process proceeds to step 194 to set the speed of the scanner motor back to 1x, and then proceeds to step 195.

In step 195, one line sync is performed, and the flow advances to step 196 to determine whether or not the output value of the output data "V2i" after the dark output correction and the shading correction is smaller than the read image signal of the previous line. If so, the process proceeds to step 200, in which the current control unit decreases the light source current value of the CIS, the process proceeds to step 201, the MTF correction coefficient is increased, and the process proceeds to step 199.

If the output value is not small in the judgment in step 196, the flow advances to step 197 to determine whether or not the output value of the output data "V2i" after the dark output correction and the shading correction is larger than the read image signal of the previous line. If the value is larger, the process proceeds to step 202, where C is set by the current controller.
The light source current value of IS is increased, and the routine proceeds to step 203, where M
The TF correction coefficient is reduced, and the process proceeds to step 199.

If the output data "V2i" after the dark output correction and the shading correction is the same as the output value of the read image signal of the previous line in the judgment of step 197, the flow advances to step 198 to set the MTF correction coefficient to a normal value. 199
Proceed to. In step 199, it is determined whether or not the document is at the end. If not, the process returns to step 195 to repeat the above-described processing. If it is, the reading of the document image is terminated.

Next, the image reading control processing at the time of the main scan will be described. At the time of the main scan, if the original output distribution information captured at the time of the prescan does not differ from the read output of the previous line of the output data “V2i”, it is determined that the original is in close contact with the contact glass, and the normal MT
Perform only F correction and continue to the next line.

On the other hand, in an area where the output distribution is low, the line is determined to be a floating document, so that the white background read output value within a predetermined range gradually decreases and is determined as an image of a binding portion of a book.
The IS control unit 7 estimates the current control unit 52
SW11 to SW13 are sequentially turned on, and the CIS
The light amount of the first LED light source 54 is increased, and the image processing unit 3 performs the correction by increasing the parameter of the MTF correction coefficient.

In the area where the output distribution is high, the original is in close contact with the contact glass, so that the read output value of the white background in a predetermined range gradually increases based on the output distribution information and the image deviates from the binding portion of the book. SW11 to SW1 according to the rise estimated from the output distribution information.
3 are sequentially turned off (OFF), and the LED light source 5 of the CIS 1 is turned off.
4, the image processing unit 3 further weakens the MTF correction coefficient to return to the normal value.

[0227]

As described above, according to the image reading apparatus of the present invention, in a CIS type image reading apparatus such as a flatbed type scanner using a contact type image sensor, a thick book is turned down. Even if a floating portion such as a binding margin sometimes occurs, it is possible to prevent “blur out of focus” and “blind black” from occurring in the read image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a scanner according to an embodiment of the present invention;

FIG. 2 is a block diagram showing a configuration of a main part of a scanner of the same magnification image reading system (CIS system) using a normal contact image sensor.

FIG. 3 is a block diagram illustrating an internal configuration of an image processing unit illustrated in FIGS. 1 and 2;

FIG. 4 is an explanatory diagram of a state when a double-page spread document is placed on a document table of the scanner according to the first embodiment of the present invention and a document floating portion;

FIG. 5 is a timing chart of various signals at the time of image reading in the scanner shown in FIG.

6 is a timing chart of various signals at the time of reading a normal planar image and an image of a document floating portion in the scanner shown in FIG. 1;

FIG. 7 is a flowchart illustrating an image reading control process in the scanner illustrated in FIG. 1;

FIG. 8 is a block diagram showing a configuration of a main part of a scanner according to a second embodiment of the present invention.

FIG. 9 is a timing chart for switching between the accumulated pulse intervals and scanner motor phase excitation in the scanner shown in FIG. 8;

FIG. 10 is a flowchart showing an image reading control process in the scanner shown in FIG.

FIG. 11 is a block diagram showing a configuration of a main part of a scanner according to a third embodiment of the present invention.

FIG. 12 is a block diagram showing a circuit configuration of a light quantity PWM control unit in FIG. 11;

FIG. 13 is a flowchart showing an image reading control process in the scanner shown in FIG. 11;

FIG. 14 is a flowchart showing an image reading control process in the scanner according to an embodiment of the present invention.

FIG. 15 is a flowchart showing an image reading control process in the scanner according to an embodiment of the present invention.

FIG. 16 is a flowchart showing an image reading control process in the scanner according to an embodiment of the present invention.

FIG. 17 is a block diagram showing a configuration of a main part of a scanner according to an embodiment of the present invention.

18 is an explanatory diagram of an image reading operation of the scanner shown in FIG.

FIG. 19 is a timing chart of the accumulation pulse interval and the motor phase excitation switching when the scanner shown in FIG. 17 reads an image.

20 is a flowchart showing an image reading control process in the scanner shown in FIG.

FIG. 21 is a block diagram showing a configuration of a main part of a scanner according to an eighth embodiment of the present invention.

FIG. 22 is a timing chart of various signals when reading an image in the scanner shown in FIG. 21;

FIG. 23 is a timing chart of various signals when the scanner shown in FIG. 21 reads a normal planar image and an image of a document floating portion.

FIG. 24 is a flowchart showing an image reading control process in the scanner shown in FIG. 21;

FIG. 25 is a block diagram showing a configuration of a main part of a scanner according to a ninth embodiment of the present invention.

26 is a circuit configuration of a current control unit shown in FIG. 25 and L of CIS.
FIG. 3 is a block diagram showing an ED light source.

FIG. 27 is a flowchart showing an image reading control process in the scanner shown in FIG. 25.

FIG. 28 is a flowchart showing an image reading control process in the scanner according to the tenth embodiment of the present invention.

FIG. 29 is a flowchart showing an image reading control process in the scanner according to the eleventh embodiment of the present invention;

FIG. 30 is a flowchart showing an image reading control process in the scanner according to an embodiment of the present invention.

FIG. 31 is an explanatory diagram of an image reading method of a “reduced optical reading method” using a CCD and an image forming lens and a “1 × image reading method” using a contact image sensor.

FIGS. 32A and 32B are explanatory diagrams showing the fluctuation characteristics of the read output when the white reference original is raised in the height direction in the reduced optical reading method and the equal-magnification image reading method.

FIG. 33 is an explanatory diagram showing the depth of focus in the reduced optical reading method and the equal-magnification image reading method, respectively.

FIG. 34 is an explanatory diagram of defocusing and blackout occurring when reading a floating document such as a binding portion of a thick book by the same-magnification image reading method.

[Explanation of symbols]

 1: Contact type image sensor (CIS) 2: A / D converter 3: Image processing unit 4: RAM 5: Signal control unit 6: CPU 7: CIS control unit 8: CLK frequency variable unit 10: Dark output correction unit 11 : Shading correction unit 12: Peak level detection unit 13: MTF correction unit 20: Book original 21: Original floating part 30: Storage time / CLK frequency variable unit 32: Scanner motor 33: Motor control unit 40: Light quantity PWM control unit

Claims (12)

[Claims] 1. An image reading apparatus of a flat bed type and a unity magnification image reading method using a contact image sensor, wherein a predetermined range of a spread page of a book placed on a platen is read during reading. When the white background reading output value gradually decreases, it is determined that the image is a binding margin portion of a book, and the pixel clock of the contact type image sensor is controlled to be longer and the MTF correction coefficient is strengthened, so that the white background reading in a predetermined range is performed. When the output value gradually increases, it is determined that the image is out of the binding margin of the book, and the pixel clock of the contact type image sensor is shortened, and the MTF correction coefficient is controlled to return to the original weak coefficient. An image reading apparatus, further comprising an image reading control means. 2. An image reading apparatus according to claim 1, wherein said image reading apparatus is a flat bed type image reading apparatus using a close contact type image sensor and which reads an image of a spread page of a book placed on a platen. If the read output value on the white background gradually decreases, it is determined that the image is of a binding portion of a book, the accumulation time and the pixel clock of the contact type image sensor are increased, the drive speed of the transport motor is reduced, and the MTF correction coefficient is reduced. When the white background reading output value in the predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the accumulation time and pixel clock of the contact type image sensor are increased, and Image reading control means for increasing the driving speed of the motor and controlling the MTF correction coefficient to return to the original weak coefficient. Apparatus. 3. An image reading apparatus of a flatbed type and an image reading method using a close-contact image sensor using a close-contact image sensor, wherein a predetermined range of a spread page of a book placed on a document table is read during reading. When the read output value on the white background gradually decreases, it is determined that the image is in the binding margin of the book, and the light amount of the light source for irradiating the facing pages is increased by PWM control and the MTF correction coefficient is increased. And
When the read output value of the white background in the predetermined range gradually increases, it is determined that the image is out of the binding portion of the book, and the light amount of the light source for irradiating the double-page spread is reduced.
An image reading apparatus, comprising: image reading control means for controlling a TF correction coefficient to return to an original weak coefficient. 4. An image reading apparatus of the same size image reading method using a contact type image sensor of a flat bed type, wherein an image of a double-page spread of a book placed on a platen is faster than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image. If the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be the image of the binding margin of the book, and the predetermined range is determined. When the read output value of the white background gradually increases, it is determined that the image is out of the binding portion of the book, and at the time of the book scan of the facing pages, the portion that is determined to be the image of the binding portion of the book has the close contact. Control is performed so as to lengthen the pixel clock of the image sensor and increase the MTF correction coefficient. Increase the pixel clock of Jisensa, and M
An image reading apparatus, comprising: image reading control means for controlling a TF correction coefficient to return to an original weak coefficient. 5. An image reading apparatus of a flatbed type, which uses a contact-type image sensor and has a same-size image reading method, in which an image of a double-page spread of a book placed on a document table is read at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image. If the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be the image of the binding margin of the book, and the predetermined range is determined. When the read output value of the white background gradually increases, it is determined that the image is out of the binding portion of the book, and at the time of the book scan of the facing pages, the portion that is determined to be the image of the binding portion of the book has the close contact. Control to increase the accumulation time and pixel clock of the image sensor, reduce the drive speed of the transport motor, and increase the MTF correction coefficient, With the know out images and determination portion increases the storage time and the pixel clock of the contact image sensor, increasing the driving speed of the conveying motor, and MT
An image reading apparatus, further comprising image reading control means for controlling the F correction coefficient to return to the original weak coefficient. 6. An image reading apparatus of a flatbed type, which uses a contact-type image sensor and has a same-size image reading method, is capable of reading an image of a double-page spread of a book placed on a platen at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image. If the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be the image of the binding margin of the book, and the predetermined range is determined. When the white background read output value gradually increases, it is determined that the image is out of the binding portion of the book, and at the time of book scanning of the facing pages, the spread is determined in the portion determined to be the image of the binding portion of the book. The light amount of the light source for irradiating the page is increased by the PWM control, and the MTF correction coefficient is controlled so as to be increased. In part to reduce the amount of light of a light source for irradiating the two-page spread, and MTF correction coefficient image reading apparatus is characterized by providing an image reading control means for controlling so as to return to the original weak coefficient. 7. An image reading apparatus of a flatbed type and an image reading method using a close-contact image sensor using a contact image sensor, wherein a predetermined range of a spread page of a book placed on a document table is read during reading. When the white background read output value gradually decreases, it is determined that the image is the image of the binding margin of the book, the drive speed of the conveyance motor of the contact type image sensor is reduced, and the sum of the output values of the image for several lines is sequentially taken. Further, control is performed so as to increase the MTF correction coefficient, and when the white background read output value within a predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the drive speed of the transport motor of the contact type image sensor is reduced. Image reading control means for increasing the number of lines for taking the sum of the output values of the image, gradually reducing the number of lines, and controlling the MTF correction coefficient to return to the original weak coefficient. Image reading apparatus for. 8. An image reading apparatus of the same size image reading method using a contact type image sensor of a flat bed type, wherein a predetermined range of a spread page of a book placed on a platen is read during reading. When the white background read output value gradually decreases, the image is determined to be an image of a binding portion of a book, the drive speed of the transport motor of the contact type image sensor is reduced, the duty of the pixel clock reset period is reduced, and the effect of the afterimage is reduced. And sum the output values of the images for several lines,
Further, control is performed so as to increase the MTF correction coefficient, and when the white background read output value within a predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the drive speed of the transport motor of the contact type image sensor is reduced. Raise the duty of the pixel clock reset period to reduce the effect of afterimages, gradually reduce the number of lines that take the sum of the output values of the image, and return the MTF correction coefficient to the original weak coefficient. An image reading device comprising an image reading control means. 9. An image reading apparatus of the same size image reading method using a contact type image sensor of a flat bed type, wherein a predetermined range of a spread page of a book placed on a platen is read during reading. If the read output value on the white background gradually decreases, it is determined that the image is of the binding margin of the book, and the light amount of the light source for irradiating the facing pages is increased.
Control is performed to increase the F correction coefficient, and when the white background read output value within a predetermined range gradually increases, it is determined that the image is out of the binding margin of the book, and the light amount of the light source for irradiating the double-page spread is reduced. And an image reading control means for controlling the MTF correction coefficient to return the original weak coefficient. 10. An image reading apparatus of a flatbed type, which uses a close contact type image sensor, and reads images of a spread page of a book placed on a platen at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image. If the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be the image of the binding margin of the book, and the predetermined range is determined. When the read output value of the white background gradually increases, it is determined that the image is out of the binding portion of the book, and at the time of the book scan of the facing pages, the portion that is determined to be the image of the binding portion of the book has the close contact. The drive speed of the transport motor of the image sensor is reduced, the output values of several lines of images are sequentially summed, and the MTF correction coefficient is controlled to be increased. In a part determined to be an image deviating from the part, the driving speed of the conveyance motor of the contact type image sensor is increased, the number of lines for summing the output values of the image is gradually reduced, and the MTF correction coefficient is also an original weak coefficient. An image reading apparatus, comprising: image reading control means for controlling the image reading device to return to the original state. 11. An image reading apparatus of the same size image reading method using a contact type image sensor of a flat bed type, wherein an image of a double-page spread of a book placed on a platen is faster than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image. If the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be the image of the binding margin of the book, and the predetermined range is determined. If the read output value of the white background gradually increases, it is determined that the image is out of the binding area of the book. The drive speed of the transport motor of the image sensor, reduce the duty of the pixel clock reset period to increase the effect of afterimages, and reduce the output value of the image for several lines. , And the MTF correction coefficient is increased so that the driving speed of the transport motor of the close contact type image sensor is increased and the pixel clock is reset in a portion where the image is determined to be out of the binding portion of the book. Image reading control means is provided to reduce the effect of afterimages by increasing the duty of the period, gradually reduce the number of lines for summing the output values of the image, and return the MTF correction coefficient to the original weak coefficient. An image reading apparatus characterized in that: 12. An image reading apparatus of a flatbed type, which uses a close-contact image sensor and has a same magnification image reading method, in which an image of a double-page spread of a book placed on a document table is read at a speed higher than a normal reading speed. The pre-scan is performed to roughly store the output distribution of the read image. If the read output value of the white background in a predetermined range gradually decreases based on the output distribution, the image is determined to be the image of the binding margin of the book, and the predetermined range is determined. When the white background read output value gradually increases, it is determined that the image is out of the binding portion of the book, and at the time of book scanning of the facing pages, the spread is determined in the portion determined to be the image of the binding portion of the book. By controlling the light amount of the light source for irradiating the page to be increased and increasing the MTF correction coefficient, in a portion determined to be an image deviating from the binding margin of the book, Serial to reduce the amount of light of the light source illuminating the facing page, and MTF correction coefficient image reading apparatus is characterized by providing an image reading control means for controlling to return the original weak coefficient.