JPH06296224A - Image reading device/method - Google Patents

Abstract

PURPOSE:To secure the satisfactory picture quality even if a read original has the local rise and fall by varying periodically the focal point and replacing an out-focus line with an in-focus line based on the image data that is moved in the secondary scanning line and read at plural positions in a single period. CONSTITUTION:A sub-unit 17 including a rod lens array 12, an IR cut filter 10 and a sensor 13 vibrates in the width of 2-3mm to a carriage casing with several lines of the secondary scanning direction defined as a single period. An action control means 34 outputs the instructions to an in-focus line detecting means 32 and an out-focus line replacing means 33 to specify several lines equivalent to a single period based on the vibrating position information on the unit 17. Thus the means 32 detects an in-focus line among scattered lines included in a designated range, and the means 33 replaces the line excluding the in-focus line with the in-focus line and outputs the image signals. Therefore the satisfactory picture quality is secured with no blur even if an original has the local rise and fall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact unit capable of obtaining two-dimensional original image data by scanning a reading unit having a one-dimensional image reading element array in parallel with an original image and capturing the image. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus using a type image reading sensor, and more particularly to an image reading apparatus and an image reading method thereof that can appropriately deal with defocus caused by ups and downs of a target document surface.

[0002]

2. Description of the Related Art Conventionally, some image reading apparatuses using a contact type image reading sensor use a one-dimensional rod lens array as an image forming optical system. Here, an image reading apparatus using the rod lens array as an image forming optical system will be described with reference to FIG. FIG. 18 is an external view of a conventional image reading device.

As shown in FIG. 18, a conventional image reading apparatus includes a reading unit 1 including an image sensor for reading an original image, a driving mechanism 2 for controlling the movement of the reading unit 1, and a reading by the driving mechanism 2. Image data read by the drive shaft 3 for moving the unit 1 and the image sensor of the reading unit 1 is subjected to processing such as adjustment of brightness level, correction of gradation characteristics, digitization as necessary, and the like, read image data. Image processing circuit 4 for outputting as
And a platen cover 5 for fixing the placed document from above.

Then, the original is fixed by the platen cover 5, the original is scanned by the reading unit 1 to read an image of one line, and the reading unit 1 is controlled by the drive mechanism 2.
Is moved linearly in the sub-scanning direction to read the image for the next one line. The image signal read by the reading unit 1 is processed by the image processing circuit 4 as read image data.

Next, the detailed structure of the reading unit 1 will be described with reference to FIG. FIG. 19 is a cross-sectional explanatory view of the conventional reading unit 1. The conventional reading unit 1 is
A pretension glass 6 as an optical system in the carriage housing 10.
An illumination device 11 for irradiating the original 7 above, a rod lens array 12 in which rod lenses for forming an image of reflected light from the original 7 are arranged in an array, and sensors such as light receiving elements as a reading system in an array. The arranged sensor array 13,
A sensor array mounting substrate 14 on which the sensor array 13 is mounted, a signal processing circuit 15 that reads signals photoelectrically converted by the sensor array 13 and outputs the signals as image signals to the image processing circuit 4 in time series, an optical system, and a reading unit. An IR cut filter 16 for cutting infrared rays between the system and the system.

In this case, the position of the original 7 is defined by the platen cover 5 and the platen glass 6.
Due to the relative positional relationship between the rod lens array 12 and the surface of the sensor array 13 with respect to the position, the focal position with respect to the document 7 is adjusted and fixed in advance when the apparatus is assembled.

However, the depth of field of the rod lens array 12 used in the contact type sensor array 13 of this type is about 1 mm at most, which is a little insufficient as a level required for an image reading apparatus. When the image is scanned at a fixed focus position on a binding part on the double-sided surface, a document with a three-dimensional object attached, a foldable document such as a map, etc. This resulted in blurring, and it was impossible to obtain a sufficient read image.

Although attempts have been made to improve the rod lens array in order to deal with this problem, considering that the rod lens array is still in an unsatisfactory state and the depth of field of the rod lens array is shallow, The theoretical limit of the image reading device used as the imaging optical system is also expected.

With respect to this problem, it has been proposed to perform a direct change of the focus in synchronization with the reading operation to obtain a better image. For example, JP-A-59-3647
As shown in the technique (conventional example 1) described in Japanese Patent Laid-Open No. 7-76, one scanning line is divided into 10 parts to operate, a read signal is sampled and held to create a histogram, and accurate image information is obtained based on the histogram. Such an image reading device has been proposed.

Further, as disclosed in the technique described in Japanese Patent Laid-Open No. 4-40746 (Prior art example 2), the reading means of the image sensor is appropriately moved along the irradiation path of the reflected light reflected on the surface of the original. An optical information reproducing apparatus has been proposed in which a predetermined line is provided at both ends of a read document to set the focus position, and the reading means is controlled based on the read signal of this line.

[0011]

However, in the image reading apparatus of the prior art 1 described above, the reading head is moved up and down at 10 KHz when one scanning line is 0.2 mm. Density (16 / mm ~
(32 lines / mm) cannot be supported, and the image is taken out by sample hold. However, if the reading operation is divided into 10 parts in vertical movement, the reading operation will be performed at a speed of 1/10 of the ordinary speed, that is, a speed that is several times faster However, there is a problem that the present feasibility is low, such as requiring a reading element for performing.

Further, in the optical information reproducing apparatus of the above-mentioned conventional example 2, as a premise, a reference line must be arranged in advance in the read image, which imposes restrictions on the read image. Although the reading device can be controlled so that the line is provided in the sub-scanning direction in the vicinity of the read document, the reading unit can be controlled to have an appropriate focus position. In such a case, there is a problem that a sufficient image quality cannot be obtained.

The present invention has been made in view of the above circumstances, and an image reading apparatus and an image reading apparatus which can obtain a sufficient image quality by controlling the focus even when the read original has local undulations. The purpose is to provide a method.

[0014]

According to a first aspect of the present invention for solving the above-mentioned problems of the conventional example, in an image reading apparatus, the focal position at a specific distance from the document surface is periodically shifted and changed. And a moving unit that moves the periodic moving unit in the sub-scanning direction, and image data at the in-focus point is detected from image data read at a plurality of positions within one period in the periodic change. It is characterized in that it has a detecting means and a replacing means for replacing the other image data excluding the in-focus image data in the one cycle with the detected in-focus image data.

According to a second aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading method, the focal position at a specific distance from the document surface is periodically shifted while moving in the sub-scanning direction. Reading is performed at a plurality of positions within one cycle while being varied, and the plurality of reading positions within the one cycle are synchronized for each cycle, and image data at the in-focus point is detected from the image data read within each cycle. It is characterized in that other image data within one cycle except for the detected in-focus image data is replaced with the in-focus image data.

According to a third aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading apparatus according to the first aspect, the detecting means calculates the variance of each image data within one cycle, and the variance is calculated. It is characterized in that the image data having the largest value is used as the detection means for detecting the in-focus image data.

According to a fourth aspect of the present invention for solving the problem of the conventional example, in the image reading method according to the second aspect, the variance of each image data within one cycle is calculated, and the variance value is the largest. The feature is that the image data is detected as in-focus image data.

According to a fifth aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading apparatus according to the first aspect, the periodically varying means integrally forms the rod lens array and the sensor array. The sub-unit and the driving unit for periodically moving the sub-unit vertically are provided.

According to a sixth aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading apparatus according to the first aspect, the periodically varying means is an optical element between the rod lens array and the sensor array. Is provided with a focal position varying device in which a liquid having a refractive index and a spectral transmittance similar to that of glass is injected, and variable operating means for variably operating the width of the focal position varying device.

According to a seventh aspect of the present invention for solving the above-mentioned problems of the conventional example, in an image reading apparatus, a periodical fluctuating means for periodically shifting and fluctuating a focal position at a specific distance from the document surface is provided. Moving means for moving the periodic moving means in the sub-scanning direction; detecting means for detecting in-focus image data from image data read at a plurality of positions within one cycle in the periodic fluctuation; It is characterized by comprising a correction means for correcting blur by using other image data excluding the in-focus image data within the cycle as a reference on the basis of the detected in-focus image data.

In order to solve the problems of the conventional example, the invention according to claim 8 is an image reading method, wherein a focal position at a specific distance from the document surface is periodically shifted while moving in the sub-scanning direction. Reading is performed at a plurality of positions within one cycle while being varied, and the plurality of reading positions within the one cycle are synchronized for each cycle, and image data at the in-focus point is detected from the image data read within each cycle. It is characterized in that other image data in one cycle excluding the detected in-focus image data is used to perform blur correction with reference to the in-focus image data.

According to a ninth aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading apparatus according to the seventh aspect, the detecting means calculates the variance of each image data within one cycle, and the variance is calculated. It is characterized in that the image data having the largest value is used as the detection means for detecting the in-focus image data.

According to a tenth aspect of the invention for solving the problems of the conventional example, in the image reading method according to the eighth aspect, the variance of each image data within one cycle is calculated, and the variance value is the largest. The feature is that the image data is detected as in-focus image data.

The invention according to claim 11 for solving the above-mentioned problems of the conventional example is the image reading apparatus according to claim 7, wherein the periodical changing means integrally forms the rod lens array and the sensor array. The sub-unit and the driving unit for periodically moving the sub-unit vertically are provided.

According to a twelfth aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading apparatus according to the seventh aspect, the periodically varying means is an optical element between the rod lens array and the sensor array. A focus position variable device, in which a liquid having the same refractive index and spectral transmittance as glass is injected,
It is characterized by having a variable operation means for variably operating the width of the focal position changing device.

According to a thirteenth aspect of the invention for solving the above-mentioned problems of the conventional example, in the image reading apparatus according to the seventh aspect, the correction means detects an in-focus image within one cycle detected by the detection means. A storage unit that stores in advance a blur amount corresponding to another image data reading position within one cycle based on the data reading position, and another within one cycle excluding the in-focus image data detected by the detection unit. And a blur correction unit that corrects the image data of 1. by the blur amount.

According to a fourteenth aspect of the present invention for solving the above-mentioned problems of the conventional example, an image reading apparatus is provided with the seventh aspect.
The image reading apparatus described above is provided with a periodic variation control means for varying the variation width of the periodic variation means on the basis of the reading position of the in-focus image data within one cycle detected by the detection means. I am trying.

According to a fifteenth aspect of the present invention for solving the problems of the conventional example, in the image reading method of the image reading apparatus according to the fourteenth aspect, when the detecting means detects the in-focus image data, It is characterized in that the fluctuation width of the cyclic fluctuation means is narrowed around the reading position of the focus image data.

According to a sixteenth aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading method according to the fifteenth aspect, if the detecting means does not detect in-focus image data, the periodic fluctuations are narrowed. The feature is that the fluctuation range of the means is returned to the original fluctuation range.

According to a seventeenth aspect of the present invention for solving the above-mentioned problems of the conventional example, in the image reading apparatus according to the fourteenth aspect, the periodic fluctuation control means does not perform the fluctuation in the periodic fluctuation means. It is characterized by being control means for controlling.

According to a eighteenth aspect of the present invention for solving the above-mentioned problems of the prior art, in an image reading apparatus, a periodical fluctuating means for periodically shifting and fluctuating a focal position at a specific distance from a document surface is provided. A moving means for moving the periodical fluctuation means in the sub-scanning direction, and 1 for the periodical fluctuation.
Detecting means for detecting in-focus image data from image data read by the reading means at a plurality of positions within a cycle, and other image data other than the in-focus image data within the one cycle are detected. Replacement means for replacing the in-focus image data with the in-focus image data, or correction means for performing blur correction with respect to other image data except for the in-focus image data in the one cycle with reference to the detected in-focus image data. An image reading apparatus having the above, wherein the reading means is formed of a plurality of sensor arrays corresponding to a color image.

According to a nineteenth aspect of the present invention for solving the problems of the conventional example, in the image reading method of the image reading apparatus according to the eighteenth aspect, a plurality of pixels corresponding to the intervals of the sensor array in the reading means are provided. It is characterized by reading in one cycle.

The invention according to claim 20 for solving the above-mentioned problems of the conventional example is the image reading method of the image reading device according to claim 18, wherein a plurality of pixels corresponding to the intervals of the sensor array in the reading means are provided. It is characterized in that it is read at a cycle of an integer.

[0034]

According to the invention described in claims 1 to 6, the focal position at a specific distance from the surface of the original is fluctuated by periodically shifting it by the periodic varying means, and the periodic varying means is moved in the sub-scanning direction. Other image data excluding the in-focus image data in one cycle by detecting the in-focus image data from the image data read at a plurality of positions in one cycle in the periodic fluctuation by the detecting means. Since the image reading device and the image reading method replace the detected in-focus image data with the replacement means, even if the read original has local undulations, the in-focus image data does not cause blurring. Image quality can be obtained.

According to the invention described in claims 7 to 13, the focal position at a specific distance from the document surface is periodically shifted by the periodic changing means to be changed, and the periodic changing means is moved in the sub-scanning direction. Other image data excluding the in-focus image data in one cycle by detecting the in-focus image data from the image data read at a plurality of positions in one cycle in the periodic fluctuation by the detecting means. Is an image reading apparatus and an image reading method in which the correction means corrects the blur based on the detected in-focus image data, the in-focus image data is By performing the blur correction based on the reference, it is possible to obtain a blur-free image quality without sacrificing the resolution in the sub-scanning direction.

According to the fourteenth to sixteenth aspects of the present invention, the image reading apparatus according to the seventh aspect is provided with the periodic variation control means for varying the variation width of the periodic variation means with reference to the in-focus image data. Since the image reading apparatus and the image reading method are used, the resolution in the sub-scanning direction is corrected by correcting the blur based on the in-focus image data in the vicinity of the in-focus reading position even if the read original has local undulations. It is possible to obtain a blur-free image quality without sacrificing.

According to the seventeenth aspect of the present invention, the image reading apparatus according to the fourteenth aspect uses the periodical fluctuation control means that does not cause the periodical fluctuation means to perform the fluctuation. Stable image quality can be obtained when reading.

According to the eighteenth to twentieth aspects of the present invention, the focal position at a specific distance from the document surface is periodically shifted by the periodic changing means to be changed, and the periodic changing means is moved in the sub-scanning direction. The image data read by the reading means at a plurality of positions within one cycle in the periodic fluctuation, and the detecting means detects the in-focus image data.
The other image data except the in-focus image data within the cycle is replaced with the detected in-focus image data by the replacement means, or the other image data except the in-focus image data within one cycle is detected. Blurring is corrected by the correction means based on the image data of the focused point, and the reading means is an image reading device formed of a plurality of sensor arrays corresponding to the color image, and the sensor in the reading means is used. Since the image reading method is one in which a plurality of pixels corresponding to the interval of the array is read in one cycle or a cycle of an integer fraction, even if the read original has local undulations, it is replaced with in-focus image data, or Image quality without blur can be obtained by performing blur correction based on the in-focus image data. Furthermore, all sensor arrays corresponding to color images are imaged at the same reading position and the same focus position. It is possible to read the can be easily performed blur correction or the like in the same condition.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. The outline of the present invention is to realize an image reading apparatus with higher image quality by providing a periodic variation mechanism of the focal position in the image reading apparatus and further combining an image processing circuit for performing correction processing etc. for local pixel groups. Is.

FIG. 1 is a sectional view of a reading unit portion of an image reading apparatus according to an embodiment of the present invention. Incidentally, FIG.
The same reference numerals will be given to portions having the same configurations as those in No. 1 for description. The reading unit in FIG. 1 corresponds to the reading unit 1 shown in the external view of the conventional image reading apparatus in FIG.

Reading unit 1 of this embodiment (embodiment 1)
Is an illuminating device 11 for irradiating the original 7 on the platen glass 6 as an optical system in the carriage housing 10, and a rod lens array 12 in which rod lenses for imaging reflected light from the original 7 are arranged in an array. And a sensor array 13 having sensors such as light receiving elements arranged in an array as a reading system, a sensor array mounting substrate 14 on which the sensor array 13 is mounted, and a signal photoelectrically converted by the sensor array 13 It has a signal processing circuit 15 for outputting to the image processing circuit 4 as an image signal in time series, and has an IR cut filter 16 for cutting infrared rays between the optical system and the reading system. Further, a subunit 17 is provided as a mechanism for periodically changing the focal position, which is a characteristic part of this embodiment.

Here, the subunit 17 includes the rod lens array 12, the IR cut filter 16, the sensor array 13, and the sensor array mounting substrate 14, and the subunit 17 is mechanically vibrated. Thus, it moves up and down along the optical axis. Therefore, the above-mentioned parts included in the subunit 17 move up and down integrally. In addition, the subunit 17 is a subunit in which a minimum necessary portion is formed to facilitate control of vibration.

The sub-unit 17 has a cycle of several lines in the sub-scanning direction with respect to the carriage housing 10 from 2 to 2.
It oscillates with a width of about 3 mm. That is, the carriage housing 10 is moved in the sub-scanning direction, the amplitude of 2 to 3 mm is set as one cycle, and the reading operation (scanning) of a plurality of lines is performed using the sensor array within this one cycle. The respective scans are synchronized, and the distance to the document 7 is constant for each scan of each cycle. Therefore, the carriage housing 10 is provided with a drive device (not shown) for vibrating the focus position so as to periodically change in synchronization with each line of each cycle.

Specifically, since the subunit 17 has the sensor array 13 and the rod lens array 12 which are linearly formed in the main scanning direction, the subunit 1
7 itself also has a linear shape in the main scanning direction, and the holding portion that holds the linear end portions of this subunit 17 moves up and down within about 2 to 3 mm by a cam and a stepping motor or an ultrasonic motor. Then, the drive mechanism 2 and the drive shaft 3 are moved so as to scan several lines, for example, about 5 lines in the sub-scanning direction for one cycle.

The image signal obtained by the reading system by this operation is a signal having a focal shift periodically for each line over several lines in the sub-scanning direction. However, among a plurality of image signals for each line, at least one line is considerably focused on a undulating original. Further, the drawback of the rod lens having a shallow depth of focus can be overcome by increasing the depth of focus of the entire device by the amplitude of 2 to 3 mm of the subunit 17.

As another embodiment (Embodiment 2) of the mechanism for periodically changing the focus position, the focus position changing device shown in FIGS. 2 and 3 will be described. FIG. 2 is a cross-sectional explanatory view of the reading unit of the second embodiment, and FIG. 3 is a cross-sectional explanatory view of the focus position varying device of the second embodiment. The reading unit of the second embodiment is basically the same in structure as the reading unit of the first embodiment shown in FIG. 1, except that the mechanism for periodically changing the focal position in FIG. Although the unit 17 is used, in FIG. 2, the focal position changing device 18 is replaced with the subunit 17 and is a mechanism for periodically changing the focal position.

The role of the focal position changing device 18 of this embodiment is to make the depth of field in image formation variable periodically between the fixed rod lens array 12 and the fixed sensor array 13. As a result, the focus position can be periodically changed.

Next, a specific structure of the focal position changing device 18 of the second embodiment will be described with reference to FIG. Example 2
As shown in FIG. 3, the focal position changing device 18 includes two transparent members 21 such as optical glass that are long in the main scanning direction in parallel with each other.
Arranged at a distance of about mm, a bellows 22 is provided between the transparent members 21 so that the distance between the transparent members 21 can be varied, and the transparent member 21 and the bellows 22 are connected by a shield 23. Further, the shield 23 is attached to the shaft 24. And the two transparent members 2
The portion surrounded by 1 and the bellows 22 is filled with, for example, a liquid 25 such as silicon oil having an optical index and a spectral transmittance that are optically similar to those of glass, and the shield 23 prevents the liquid 25 from leaking. It has a role of shielding. still,
The liquid 25 having the same refractive index and spectral transmittance as glass is specifically described in JP-A-2-10309, JP-A-4-11470 and JP-A-4-21832. ing.

The portion of the shield 23 that supports the transparent member 21 is connected to a driving device (not shown) that generates a small vibration (amplitude), such as an ultrasonic motor that operates by an electric signal, at a specific cycle. The operation is performed so that the relative distance between the two transparent members 21 is variable. Specifically, the relative distance between the two transparent members 21 is made variable so as to synchronize with the movement of the carriage housing 10 in the sub-scanning direction in units of several lines, and the optical focus position is changed to a desired cycle. It is controlled by the amplitude. As a result, a periodic focus shift is intentionally provided for every several lines to provide a periodic focus position variation mechanism for periodically varying the focus position.

By the mechanism of periodical fluctuation of the focal position,
Even if you scan an image of a document that has local undulations,
Since there is always a line that is in focus within a certain threshold value for every several lines, if the image processing circuit 4 performs image processing using this in-focus image data, the resolution will deteriorate to some extent. However, as a whole, a good image with little blurring can be obtained.

Next, an image processing method and an image processing circuit for converting the image signal read by the image reading apparatus having the reading units of the first and second embodiments into high-quality image data will be described. In brief, high-quality image data can be obtained by periodically changing the focus position and replacing the read image signal with an in-focus image signal or performing blur correction processing.

First, image processing by replacement will be described with reference to FIG. FIG. 4 is a circuit configuration block diagram of an image processing circuit (first image processing circuit) by replacement. The image processing circuit (first image processing circuit) of FIG. 4 issues a buffer memory 31 for storing and accumulating the input image signal as image data on a line-by-line basis, and an instruction for specifying a plurality of lines corresponding to one cycle based on the vibration position information. Output operation (M
ode) control means 34, in-focus line detection means 32 that calculates the variance for each line for image data of a specific plurality of lines, and detects the line with the largest variance, and another period of one cycle of the detected image data. It is composed of a defocus line replacing means 33 for replacing a line (defocus line).

Therefore, the operation control means 34 outputs an instruction (range specification instruction) for specifying a plurality of lines for one cycle from the vibration position information to the in-focus line detection means 32 and the defocus line replacement means 33. The in-focus line detection means 32 detects the in-focus line by calculating the variance within the lines in the designated range, and the out-of-focus line replacement means 3
3 is a line for replacing an in-focus line other than the in-focus line (that is, a line out of focus: a defocus line) with a in-focus line and outputting an output image signal.

More specifically, several pixels (M pixels, for example, 32 pixels) appropriately divided in the main scanning direction over several lines (N lines, for example, 5 lines) obtained by the periodical fluctuation of the focus position. Pixel), then N
By repeating the image processing for the block of × M pixels, the image data of one line determined to be in best focus is replaced with the image data of the remaining N−1 lines.

Here, the necessary algorithm is an algorithm for detecting the in-focus line in the in-focus line detecting means 32, which can be calculated by the following operation. For a block of N × M pixels, the variance over the M pixel data (representing brightness) of each line is calculated. If the variance is calculated for the neighboring images, the image obtained by focusing the most becomes the sharpest image, so using the relationship that the line with the largest variance value is the most focused, If a circuit for calculating and comparing N variance values is configured, a desired in-focus line detecting means can be realized. After the in-focus line is detected by this, the defocus line replacement circuit 33 replaces the image data of the remaining N-1 lines (defocus line) with the image data of the in-focus line and outputs it as an output image signal.

According to the image reading apparatus having the first image processing circuit and the image processing method in the image reading apparatus, the image data of the defocus line is replaced with the image data of the in-focus line. Although the resolution is sacrificed to some extent, there is an effect that image data with less blurring can be obtained as a whole.

Next, the image processing circuit (second image processing circuit) shown in FIG. 5 will be described. FIG. 5 is a circuit configuration block diagram of an image processing circuit (second image processing circuit) for blur correction. The second image processing circuit outputs a buffer memory 31 that stores the input image signal as image data on a line-by-line basis, and an operation (Mode) control unit that outputs an instruction to specify a plurality of lines corresponding to one cycle based on the vibration position information. 34, the in-focus line detection means 32 that calculates the variance for specific plural lines of image data and detects the line with the largest variance, and the other line (defocus line) of one cycle in the detected image data. A defocus line blur correction unit 36 for correcting blur and a blur correction filter 35 for storing and storing the defocus amount with respect to other lines in the case where each line in one cycle is a focused line are stored in a table format. There is.

The second image processing circuit is different from the image processing circuit (first image processing circuit) of FIG. 4 in that instead of the defocus line replacement means 33, the defocus line blur correction means 36 and the blur correction are performed. That is, a blur correction filter 35 that serves as a reference is provided.

More specifically, the blur correction filter 3
In reference numeral 5, the amount of deviation of other lines from the optical line between the document and the reading unit with respect to the reference line is stored in advance, and when the in-focus line detection means 32 detects the in-focus line. The information of the in-focus line is transmitted to the operation control means 34, the information indicating which line has become the in-focus line is received from the operation control means 34, and the in-focus line is used as a reference line to set the blur amount of other lines. It is read and output to the defocus line blurring correction unit 36.

Then, the defocus line blurring correction means 36
Receives an instruction (range specifying instruction) for specifying a plurality of lines for one cycle from the operation control means 34, receives information of the in-focus line within the range from the in-focus line detecting means 32, and further, the buffer memory 31. The image data is read for a specific range according to a range specifying instruction, the blur amount of another line with respect to the reference line is read from the blur correction filter 35 using the focused line as a reference line, and the blur amount of the other line excluding the reference line is read. The image data is corrected and output as an output image signal.

More specifically, the detection of the in-focus line is similar to the processing in the first image processing circuit, but after the in-focus line is detected, the remaining N points are detected by the vibration position information.
Since the amount of defocus for pixels on line -1 is known,
Blurring correction file 3 prepared in advance according to the amount of defocus
5, the defocus line blur correction unit 36 selectively applies the N-1 line to the output image signal in which the blur is corrected.

According to the image reading apparatus having the second image processing circuit and the image processing method in the image reading apparatus, the image data of the defocus line is stored in the blur correction filter 35 in advance on the basis of the image data of the in-focus line. Since the correction is performed with the amount of blurring, there is an effect that image data without blurring can be obtained without sacrificing the resolution in the sub-scanning direction.

Next, the image processing circuit (third image processing circuit) shown in FIG. 6 will be described. FIG. 6 is a circuit configuration block diagram of an image processing circuit (third image processing circuit) by blur correction using a periodic fluctuation control circuit. The third image processing circuit is based on the second image processing circuit of FIG. 5, and is provided with a periodic fluctuation control circuit 38 for controlling the periodic fluctuation mechanism 37 in accordance with information from the in-focus point line detection means 32. .

More specifically, the periodical change mechanism 37 is a mechanism for periodically changing the reading unit shown in FIG. 1 or 2 vertically, and is realized by using a motor and a cam. Is. However, the periodic fluctuation mechanism 37 in this case has a mechanism capable of varying the amplitude at a position of a specific distance from the document under the control of the cyclic fluctuation control circuit 38. Therefore, the periodic fluctuation mechanism 37 can change the amplitude within a width of several steps, and the vicinity of the focal position is detected according to the information indicating the focal position transmitted from the periodic fluctuation control circuit 38 (information on the in-focus line). The amplitude is made variable around the point of.

Further, the periodic fluctuation control circuit 38 transmits the vibration position information to the operation control means 34 from the information such as the number of rotations of the motor in the periodic fluctuation mechanism 37, and also gives the range specifying instruction from the operation control means 34. Based on the information of the in-focus line detected by the in-focus line detection means 32 based on the information, the center position (center position of amplitude) of the periodic operation of the periodic changing mechanism 37 and the change width are further received from the information of the in-focus line. The control is performed to make (amplitude) variable.

The control of the periodic fluctuation control circuit 38 will be described with reference to FIGS. 7A and 7B. When 5 lines are read in one cycle, the optical distance between the original document and the reading unit is reduced in 2 to 3 seconds. When the distance fluctuates between A and B (about 2 mm) (this operation is referred to as Mode-1), when the in-focus line detecting means 32 detects the in-focus line near the position C, the in-focus line detecting means is detected. 32: Focus line information (position C
7) so that the width of the amplitude fluctuates small around the position C as a center.
As shown in (b), the periodic fluctuation mechanism 37 is controlled (this operation is referred to as Mode-2). It corresponds to the standard case where the position A is focused on the platen position.

As a result, the periodic fluctuation mechanism 37 makes small fluctuations in the vicinity of the focus position to read 5 lines, so that the detection of the in-focus line (detection of the focus position) becomes more accurate, and this amplitude is further detected. Since it operates so as to detect the in-focus line within the range, the in-focus line can be detected even more accurately.

Further, when the periodic fluctuation mechanism 37 makes periodic fluctuations within a small amplitude range near the focus position and the focus position suddenly deviates from the above range due to the ups and downs of the document, the in-focus position is reduced. The focus detection line 3 detects information that the focus detection line cannot be detected by the line detection unit 32 and the focus detection line cannot be detected (focus detection line non-detection information).
2 will be received by the cyclic fluctuation control circuit 38,
This focal point line non-detection information is used for the periodic fluctuation control circuit 38.
Performs control for returning the center position of the periodic fluctuation and the width of the periodic fluctuation to the initial state, for example, Mode-1. This makes it possible to deal with a sudden change in the focus position of the document, and it is possible to obtain image data in which the focus position matches.

The control method of the periodic control circuit 38 will be described with reference to the flowchart of FIG. First, the settings of the period and amplitude are initialized (100).
In this initialization, not only the amplitude in Mode-1 but also the amplitude in Mode-2 is set, and the total number of scans is set in advance.

Next, in Mode-1, the periodic fluctuation mechanism 37 is used.
Is operated (101), and it is judged whether or not the in-focus line is detected based on the in-focus line information from the in-focus line detection means 32 (102). When the in-focus point is detected, the Mod is set.
At e-2, the periodic fluctuation mechanism 37 is operated (103).
However, the shift to the scan of Mode-2 is delayed by two cycles (two peaks) after the in-focus point is detected due to the circuit delay.

If the focus line is not detected (1
02), it is determined whether or not a predetermined number of scans have been completed (104), and if the scan is not completed, the process returns to step 101 to perform Mode-1 scan, and the predetermined scan is completed. If so, the process ends. In addition, after the operation of Mode-2 (103), it is determined whether or not a predetermined number of scans are completed (105), and if the scan is not completed, the process returns to step 102 and the scan is completed. If so, the process ends.

The control method described above is the simplest example, but the number of cycles in Mode-1 and Mode-2 is set to a specific number in advance, and this specific number is set as a block.
By shifting from Mode-1 to Mode-2 at the end of the block cycle (for example, three cycles), it is possible to obtain a stable read image with little fluctuation in the focus position, and to further block one block ( The focus position is detected in the first 1 cycle (3 cycles) and the result is 2 blocks (4 cycles).
The effect of making it possible to prevent the circuit from becoming complicated due to the circuit delay and to easily realize the control of the circuit.

According to the image reading apparatus having the third image processing circuit and the image processing method in the image reading apparatus, the information regarding the distance to the document is unknown or the focus position is lost in the control procedure. Even when the focus position is determined by operating the standard periodic fluctuation mode,
The information of the focus position is fed back within a few cycles from the detection of the focus position, and the mode of narrow amplitude near the focus position is obtained.
Since the in-focus line detection is carried out in order to carry out the blur correction, there is an effect that the deterioration of the image quality in the defocused portion due to the operation of the periodical fluctuation mechanism 37 can be suppressed.

Incidentally, in order to correspond to the above embodiment, FIG.
The blur correction filter 35 has a standard periodic fluctuation (Mod
It is necessary to have not only a correction value for e-1) but also a correction value for a periodic fluctuation (Mode-2) of a narrow amplitude.

In the examples of FIGS. 7 and 8, two types of operation modes are used for the variable control of the periodic fluctuation mechanism 37. However, if there are a plurality of modes more than this, finer dynamic control is performed. Therefore, the blur correction of the defocus line can be effectively performed.

Further, the third image processing circuit of FIG.
Although it is formed on the basis of the second image processing circuit of FIG. 4, it may be formed on the basis of the first image processing circuit of FIG.
The image processing circuit in this case is shown as a fourth image processing circuit in FIG. 9 of the circuit configuration block diagram. As shown in FIG. 9, the fourth image processing circuit controls the periodic fluctuation mechanism 37 by the periodic fluctuation control circuit 38 to detect the in-focus line near the focal position, and the defocus line replacement means 33. Since several other lines are replaced with the image data of the in-focus line, the resolution in the sub-scanning direction is somewhat sacrificed, but other lines can be replaced with lines that are very close to the focus, and there is almost no blurring. You can get image data,
High image quality can be achieved.

Further, although the third image processing circuit is provided with the periodic fluctuation mechanism 37 and the periodic fluctuation control circuit 38, these mechanisms are not used, for example, when reading an image of a flat original. If a selection switch is provided so that it can be operated at any time, the usability can be improved.

It is also conceivable that the reading units of the first and second embodiments shown in FIGS. 1 and 2 are color-compatible reading units as shown in FIGS. 10 and 11, and an image reading apparatus compatible with color images is formed. . FIG. 10 is a cross-sectional explanatory view of the reading unit corresponding to the color of the reading unit of the first embodiment, and FIG. 11 is a cross-sectional explanatory view of the reading unit corresponding to the color of the reading unit of the second embodiment.

The reading unit shown in FIGS. 10 and 11 is more specifically a color of R (red) G (green) B (blue) than the reading units of Examples 1 and 2 shown in FIGS. 3 rows of sensor arrays 13R, 13G, 13B are formed on the sensor array mounting substrate 14 so that the wavelengths of the respective colors can be read, and the filter 16 that transmits only the wavelength components of each color
R, 16G, 16B are sensor arrays 13R, 13G,
13B formed on 13B, and further, RGB sensor array 1
Rod lens arrays 12R, 12G, 12B are formed corresponding to 3R, 13G, 13B.

Here, the sensor arrays 13R, 13G, 1
Since 3B is integrally formed on the sensor array mounting substrate 14, the three rows of sensor arrays 13R, 13G, and 13B in the reading unit of FIG. 10 simultaneously move up and down along the optical axis to have the same focus. Position,
In the reading unit of FIG. 11, the focal position changing device 18 vibrates and the three rows of sensor arrays 13R, 13G, and 13B have the same focal position.

Then, the sensor arrays 13R and 13 in three rows are arranged.
Among the G and 13B, for any one of the sensor arrays, for example, the sensor array 13R, the focusing line is detected by the control method of FIGS. 7 and 8 using the circuits of FIGS. 4 to 6 and 9. . At this time, the sensor arrays 13G on the other columns,
The image of 13B is also read, and the image data is stored and accumulated in the buffer memory. Then, regarding the pixels G and B read in the portions where the periods in which the sensor arrays 13R, 13G, and 13B fluctuate vertically overlap, the focusing lines for the pixels R of the sensor array 13R are set as the focusing lines, and three rows of sensor arrays are used. 13R, 13
For G and 13B, defocus line replacement or defocus line blur correction is performed. By doing so, a low-cost image reading apparatus can be realized without complicating the circuit configuration and processing.

However, as shown in the schematic operation diagram of FIG. 12, when the focus movement period is 8 pixels, the width between the sensor arrays 13 is 6 pixels, and the movement of the focus position is in 5 steps, the following is performed. There are drawbacks described in. Here, the focus movement period of 8 pixels means that the number of pixels moved in the sub-scanning direction while one pixel moves up and down is 8 pixels, and R
The width between the arrays of GB (between colors) is 6 pixels, which means that the width of RGB pixels is 6 pixels. Note that the movement of the focal point is in 5 steps, but for each color sensor, 1
The image of 8 pixels is read in a cycle so that the omission of reading of pixels in one cycle does not occur.

When an image is read by moving in the sub-scanning direction while periodically moving up and down as shown in FIG.
Assuming that the pixel R is a reference pixel for detecting the in-focus position, the pixel G has one cycle later than that of the pixel R, and the pixel B has two cycles of the next cycle. The overlapping periods are set, and all the pixels in this period are replaced by the defocus position or the defocus position is corrected by the in-focus position detected by the pixel R.

However, as shown in FIG. 12, since the periods of the respective pixels for which the blurring correction and the like are performed are not completely the same, all the RGB pixels at the same reading position are necessarily subjected to the blurring correction and the like under the same conditions. However, in that case, each pixel reads an image at a different focus position at the same reading position, and there is a drawback that blur correction and the like cannot be sufficiently performed.

Specifically, the above-mentioned drawback will be described with reference to FIG. 13. In a portion where the RGB pixel periods overlap near the reading position x in the sub-scanning direction, the periods of the pixels R and G at the reading position x coincide. However, at the reading position x, the pixel B becomes the pixel at the beginning of the next cycle and does not match the cycle of the pixels R and G. Therefore, the pixels R and G are subjected to the blur correction or the like under the same condition, but the pixel B is subjected to the blur correction or the like on the basis of the in-focus position detected by the pixel R in the next cycle. Since each of the combined pixels has not been subjected to blur correction or the like under the same conditions, in-focus image data cannot always be obtained at the reading position x, and the image may not be read accurately.

If all the read pixels of RGB at the read position x are read at the same focus position, the same blur correction or the like can be performed on the other pixels G and B with the focus position of the pixel R as a reference. However, in the example shown in FIG. 13, the blur correction is performed at the focal position of R at 5, G at 3, and B at 1 at the reading position x in the sub-scanning direction. In order to perform this, there is also a disadvantage that different processes such as blur correction are performed on each pixel, and the process becomes complicated.

Therefore, as shown in the schematic operation diagram of FIG. 14, when the focus movement period is 6 pixels, the intercolor 6 pixels, and the movement of the focus position is in four stages, the movement periods of all the pixels of RGB are completely uniform. Therefore, as shown in FIG. 15, at the reading position x in the sub-scanning direction, the focal positions of the pixels R, G, and B coincide with each other at the focal position of 1. Therefore, the drawbacks described in FIGS. 12 and 13 are solved. can do.

That is, regarding the movement cycle of the pixels R, G and B, one cycle of the pixel G and two cycles of the pixel B with respect to the cycle of the pixel R are completely overlapped with the next cycle as shown in FIG. In FIG. 11, the periodical changing mechanism and the driving mechanism of the subunit 17 are controlled, and in FIG. 11, the periodical changing mechanism and the driving mechanism of the focus position changing device 18 are controlled. Here, the periodic fluctuation mechanism controls vertical movement, and the drive mechanism controls the movement distance in the sub-scanning direction.

Further, as another embodiment, as shown in the schematic operation diagram of FIG. 16, the focus movement cycle is 6 pixels, the intercolor 12 pixels, and the movement of the focus position is performed in four steps. It is possible to solve the drawback described in. In other words, it is 1/1/2 of the number of pixels between colors (12 pixels)
17, the pixel R4, the pixel G2, and the pixel B0 can be read at the same focal point at the reading position x. In this case, the pixel G4 with respect to the cycle of the pixel R can be read.
For two cycles and the pixel B for four cycles completely overlaps with the next cycle. Therefore, the periodic fluctuation mechanism and the driving mechanism are controlled so that the fluctuation cycle is set to be an integer fraction of the number of pixels between colors. Note that 1 / the number of pixels between colors is 1
It shows that it becomes / 2, 1/3, 1/4, ....

Then, the processing such as the blur correction in the periodic fluctuations of FIGS. 16 and 17 is performed by each sensor array 13R, 13R.
For the pixels read at G and 13B, the image data is stored and accumulated in the buffer memory, and the pixels read at the portions where the periods of the pixels overlap, for example, all the in-focus positions detected by the pixel R are used as a reference. The out-of-focus replacement or the out-of-focus blur correction is performed for the pixels of.

Color-corresponding 3 shown in FIGS. 10 and 11.
When the sensor arrays 13R, 13G, 13B in a row are periodically changed to detect the in-focus line with respect to the sensor array in the one row and the defocus line is replaced or the defocus line is defocused, FIG. As shown in FIG. 17, the focus movement cycle is made to match the number of pixels between colors (the number of pixels in the focus movement cycle = the number of pixels between colors) or the focus movement cycle is changed between colors. By setting the number to be an integer fraction of the number of pixels (the number of pixels between colors / the number of pixels of the focus movement period = an integer), the periods of the RGB sensor arrays completely overlap. Therefore, all the RGB pixels are subjected to blur correction under the same conditions, and the in-focus image data can be obtained at the same reading position, and there is an effect that the image can be read accurately. All of RGB at the reading position Since the read pixels are read at the same focus position, the same blur correction or the like can be performed on the other sensor arrays with reference to the in-focus line of one sensor array, and the blur correction processing or the like can be facilitated. effective.

[0092]

According to the invention described in claims 1 to 6, the focal position at a specific distance from the document surface is periodically displaced by the periodical changing means to be changed, and the periodical changing means is moved in the sub-scanning direction. To the image data read at a plurality of positions within one cycle in the periodic fluctuation by the detecting means, and the image data of the in-focus area within one cycle is removed. Since the image reading device and the image reading method replace the image data with the detected in-focus image data by the replacing means, even if the read original has local undulations, it is blurred by the in-focus image data. There is an effect that it is possible to obtain a free image quality.

According to the seventh to thirteenth aspects of the present invention, the focal position at a specific distance from the document surface is periodically shifted by the periodical changing means to be changed, and the periodical changing means is moved in the sub-scanning direction. Other image data excluding the in-focus image data in one cycle by detecting the in-focus image data from the image data read at a plurality of positions in one cycle in the periodic fluctuation by the detecting means. Is an image reading apparatus and an image reading method in which the correction means corrects the blur based on the detected in-focus image data, the in-focus image data is By performing the blur correction based on the reference, it is possible to obtain a blur-free image quality without sacrificing the resolution in the sub-scanning direction.

According to the fourteenth to sixteenth aspects of the present invention, the image reading apparatus according to the seventh aspect is provided with the periodic variation control means for varying the variation width of the periodic variation means with reference to the in-focus image data. Since the image reading apparatus and the image reading method are used, the resolution in the sub-scanning direction is corrected by correcting the blur based on the in-focus image data in the vicinity of the in-focus reading position even if the read original has local undulations. It is possible to obtain a blur-free image quality without sacrificing the image quality.

According to the seventeenth aspect of the invention, the image reading apparatus according to the fourteenth aspect uses the periodic fluctuation control means that does not cause the fluctuation by the periodic fluctuation means. There is an effect that a stable image quality can be obtained when reading.

According to the eighteenth to twentieth aspects of the present invention, the focal position at a specific distance from the document surface is periodically shifted by the periodic changing means to be changed, and the periodic changing means is moved in the sub-scanning direction. The image data read by the reading means at a plurality of positions within one cycle in the periodic fluctuation, and the detecting means detects the in-focus image data.
The other image data except the in-focus image data within the cycle is replaced with the detected in-focus image data by the replacement means, or the other image data except the in-focus image data within one cycle is detected. Blurring is corrected by the correction means based on the image data of the focused point, and the reading means is an image reading device formed of a plurality of sensor arrays corresponding to the color image, and the sensor in the reading means is used. Since the image reading method is one in which a plurality of pixels corresponding to the interval of the array is read in one cycle or a cycle of an integer fraction, even if the read original has local undulations, it is replaced with in-focus image data, or Image quality without blur can be obtained by correcting blur based on the in-focus image data, and all sensor arrays corresponding to color images can be imaged at the same reading position at the same focus position. It is possible to read the, there is an effect that can perform blur correction or the like easily under the same conditions.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory diagram of a reading unit according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory diagram of a reading unit according to a second embodiment.

FIG. 3 is a cross-sectional explanatory diagram of a focal position changing device according to a second embodiment.

FIG. 4 is a circuit configuration block diagram of a first image processing circuit.

FIG. 5 is a circuit configuration block diagram of a second image processing circuit.

FIG. 6 is a circuit configuration block diagram of a third image processing circuit.

FIG. 7 is a diagram for explaining a variable control method of the periodic fluctuation mechanism.

FIG. 8 is a flowchart showing a control method in the periodic fluctuation control circuit.

FIG. 9 is a circuit configuration block diagram of a fourth image processing circuit.

FIG. 10 is a cross-sectional explanatory view of a reading unit in which the reading unit of the first embodiment is color-enabled.

FIG. 11 is a cross-sectional explanatory view of a reading unit in which the reading unit of the second embodiment is color-enabled.

FIG. 12 is an operation schematic diagram of a sensor array of a color-compatible reading unit.

13 is a schematic diagram illustrating a reading state in the operation of FIG.

FIG. 14 is an improved operational schematic diagram of a sensor array of a color-enabled reading unit.

FIG. 15 is a schematic diagram illustrating a reading state in the operation of FIG.

FIG. 16 is another improved operational schematic of a sensor array of a color-enabled reading unit.

FIG. 17 is a schematic diagram illustrating a reading state in the operation of FIG.

FIG. 18 is an external view of a conventional image reading apparatus.

FIG. 19 is a cross-sectional explanatory view of a conventional reading unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reading unit, 2 ... Drive mechanism, 3 ... Drive shaft, 4 ... Image processing circuit, 5 ... Platen cover, 6
... Platen glass, 7 ... Original, 10 ... Carriage housing, 11 ... Illumination device, 12 ... Rod lens array,
13 ... Sensor array, 14 ... Sensor array mounting substrate, 15 ... Signal processing circuit, 16 ... IR cut filter, 17 ... Sub unit, 18 ... Focus position changing device, 21 ... Transparent member, 22 ... Bellow, 23 ... Seal, 24 ... Shaft, 25 ... Liquid, 31 ... Buffer memory, 32 ... Focus line detection means, 33 ...
Defocus line replacement means 34 ... Operation (Mode)
Control means, 35 ... blur correction filter, 36 ... defocus line blur correction means, 37 ... periodic fluctuation mechanism, 3
8 ... Periodic fluctuation control circuit

Front page continued (72) Inventor Naosuke Ino 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (20)

[Claims] 1. A periodic fluctuation means for periodically shifting and fluctuating a focal position at a specific distance from a document surface, a moving means for moving the periodic fluctuation means in a sub-scanning direction, and a periodic fluctuation in the periodic fluctuation. A detection unit that detects in-focus image data from image data read at a plurality of positions within one cycle, and other image data other than the in-focus image data within the one cycle of the detected in-focus points. An image reading apparatus comprising: a replacement unit that replaces image data. 2. A focal position at a specific distance from the document surface is moved in the sub-scanning direction while being periodically shifted and varied to read at a plurality of positions within one cycle, and a plurality of positions within the one cycle are read. The reading position is synchronized in each cycle, the in-focus image data is detected from the image data read in each cycle, and the other image data in one cycle except the detected in-focus image data is used as the in-focus point. The image reading method is characterized in that the image data is replaced with the image data. 3. The detecting means is a detecting means for calculating the variance of each image data within one cycle and detecting the image data having the largest variance value as the in-focus image data. The image reading device described. 4. The image reading method according to claim 2, wherein the variance of each image data in one cycle is calculated, and the image data having the largest variance value is detected as the in-focus image data. 5. A sub-unit in which the periodic varying means integrally forms a rod lens array and a sensor array,
The image reading apparatus according to claim 1, further comprising a driving unit that periodically moves the sub unit up and down. 6. The focal position changing device, wherein the periodical changing means is provided between the rod lens array and the sensor array, injecting a liquid having a refractive index and a spectral transmittance which are optically similar to those of glass, and the focus position changing device is provided. 2. The image reading apparatus according to claim 1, further comprising a variable operation means for variably operating the width of the position variable apparatus. 7. A periodic varying means for periodically shifting and varying a focus position at a specific distance from the document surface, a moving means for moving the periodic varying means in the sub-scanning direction, and a periodic variation in the periodic variation. A detection unit that detects in-focus image data from image data read at a plurality of positions within one cycle, and other image data other than the in-focus image data within the one cycle of the detected in-focus points. An image reading apparatus, comprising: a correction unit that corrects a blur based on image data. 8. A focal position at a specific distance from the document surface is moved in the sub-scanning direction while being periodically shifted and varied to read at a plurality of positions within one cycle, and a plurality of positions within the one cycle are read. The reading position is synchronized in each cycle, the in-focus image data is detected from the image data read in each cycle, and the other image data in one cycle except the detected in-focus image data is used as the in-focus point. An image reading method characterized by performing blur correction based on the image data of 1. 9. The detecting means is a detecting means for calculating the variance of each image data within one period and detecting the image data having the largest variance value as the in-focus image data. The image reading device described. 10. The image reading method according to claim 8, wherein the variance of each image data within one cycle is calculated, and the image data having the largest variance value is detected as the in-focus image data. 11. The periodical changing means has a subunit in which a rod lens array and a sensor array are integrally formed, and a driving means for periodically moving the subunit up and down. 7. The image reading device described in 7. 12. The focal position changing device, wherein the periodical changing means is provided between the rod lens array and the sensor array, injecting a liquid having a refractive index and a spectral transmittance which are optically similar to those of glass, and the focus position changing device is provided. 8. The image reading apparatus according to claim 7, further comprising a variable operation means for variably operating the width of the position variable device. 13. The correction means detects the 1 detected by the detection means.
Storage means for previously storing the blur amount corresponding to the reading position of other image data in one cycle with reference to the reading position of the in-focus image data in the cycle, and the in-focus image data detected by the detecting means 8. The image reading apparatus according to claim 7, further comprising: a blur correction unit that corrects other image data in one cycle except for the blur amount according to the blur amount. 14. The image reading apparatus according to claim 7, wherein the fluctuation range of the cyclic fluctuation means is variable based on the reading position of the in-focus image data in one cycle detected by the detection means. An image reading apparatus comprising a control means. 15. The variation range of the periodic variation means is narrowed around the reading position of the in-focus image data when the in-focus image data is detected by the detection means. Image reading method of image reading device. 16. The image reading method according to claim 15, wherein the fluctuation range of the narrowed cyclic fluctuation means is returned to the original fluctuation width when the detection means does not detect focused image data. 17. The image reading apparatus according to claim 14, wherein the periodic fluctuation control means is a control means for controlling so as not to perform fluctuations by the periodic fluctuation means. 18. A periodic changing means for periodically shifting and changing a focal position located at a specific distance from the document surface, and a moving means for moving the periodic changing means in the sub-scanning direction.
Detection means for detecting in-focus image data from image data read by the reading means at a plurality of positions in one cycle in the periodic fluctuation, and other than the in-focus image data in the one cycle Replacement means for replacing image data with the detected in-focus image data, or other image data other than the in-focus image data in the one cycle is blurred based on the detected in-focus image data. An image reading apparatus having a correction unit for performing correction, wherein the reading unit is formed of a plurality of sensor arrays corresponding to a color image. 19. The image reading method for an image reading apparatus according to claim 18, wherein a plurality of pixels corresponding to the intervals of the sensor array in the reading means are read in one cycle. 20. An image reading method for an image reading apparatus according to claim 18, wherein a plurality of pixels corresponding to the intervals of the sensor array in the reading means are read in a cycle of an integer fraction.