JPH11341239A - Device and method for picture reading and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable picture data to be simultaneously displayed on a preview screen by reading a front side and a rear side of an original. SOLUTION: This device is provided with a first document reading part 204 and a second document reading part 209 for reading both a front side and a rear side of a document and generating picture data, a storage part 101 for storing the generated picture data, and a writing/reading control means 102 for controlling writing operation to the storage part 101 and reading operation from the storage part. When timings for starting reading and the front side and the rear side of the document are different, the picture data of the front side of the document and the picture data of the rear side are enabled to be outputted in turn to external equipment 314 so that the picture data obtained between the time when reading of one of the document surfaces is started and the time when reading of the other document surface is started is stored in the storage part 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, an image reading method, and a storage medium, and more particularly, to an image reading apparatus that reads both sides of a document and converts it into an electric signal, and digitizes and transfers the signal to an external device. Things.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a mechanism of an image reading apparatus for reading both sides of a document. As shown in FIG. 3, by inserting the document 201 into a document insertion portion (not shown),
When the document detection lever 202 is tilted, the photo interrupter 20
The output of 3 changes. As a result, it is determined that the document 201 has been inserted, and the motor (not shown) is driven to rotate the first document conveying roller 210a to draw the document 201 into the main body of the image reading apparatus and to read the image data. Start.

[0004] 204 and 209 are first and second contact type line image sensors (hereinafter referred to as CIS (Contact Image Sensor)).
It comprises an LED array 205, a lens 206, a sensor array 207 in which a plurality of photodiodes are arranged in a row, a glass plate 208 with which the original 201 contacts, and the like.

The operation of the first CIS 204 and the second CIS 209 is as follows.
The reflected light from 1 is condensed by a lens 206, and the formed optical image is photoelectrically converted into a voltage value in accordance with the brightness of the optical data obtained from the original 201 by a sensor array 207 and read line by line. ing. The document 201 that has been read is discharged outside the image reading apparatus by the rotation of the second document conveying roller 210b.

Next, the flow of processing of document data will be described with reference to the block diagram shown in FIG. First, the first
The original data is converted into a voltage value for each line by the CIS 204 and the second CIS 209 and read, and the amplitude is adjusted by the first and second amplifiers 301 and 302. Then, the first and second A / D conversion circuits are formed. At 303 and 304, analog image data is converted to digital image data.

Next, the output from the first and second A / D conversion circuits 303 and 304 is alternately switched line by line by a 2-1 selector 305 and output.

Next, shading correction is performed by a shading correction circuit 306. The above shading correction is
By correcting that the LED light irradiating the original 201 does not uniformly hit the original 201, that the sensitivity of each sensor in the sensor array varies, and that the amount of transmitted light becomes worse as the lens approaches the end, etc. is there.

In the shading correction method, data of a white sheet for correction read in advance is stored in the shading RAM 307, and the difference between the value and a target value is stored in the shading RAM 307 as correction data. Then, at the time of reading a document, correction is performed using the correction data.

On the other hand, a peak detection circuit 308 detects the peak value of the image data line by line, and uses it to detect the leading edge of the document 201. The gamma conversion circuit 309 performs contrast conversion.

The packing / buffer RAM control circuit 310 packs the image data in units of n (n = 1, 2, 3,..., N) bits and collectively packs the image data into a computer 314 as an external device.
Control for temporarily writing image data to the buffer RAM 311 and control for reading data to the interface circuit 312 are performed in order to match the timing of communication with the interface circuit 312.

The interface circuit 312 exchanges control signals with the computer 314 and controls output of image data. By performing such processing, the image data of the front side and the back side of the document 201 are alternately transferred to the computer 314 line by line.

The control of each section described above is performed by a computer (CPU) 313. Where the computer 31
The image data transferred to 4 is displayed on a screen of a monitor 316 connected to the computer 314 by image reading software 315 stored in the computer 314.

The display screen of the monitor 316 is a preview screen in which image data is thinned out and reduced. During the reading operation of the original 201, the transferred image data is sequentially displayed. Can be confirmed.

In FIG. 3, the first CIS 204 and the second CIS 204
Although the position of the CIS 209 is fixed and the mechanism for transporting the original 201 is shown, the position of the original 201 is fixed, and the first CIS 204 and the second
Of the CIS 209 may move.

[0015]

Here, the conventional display operation of the preview screen has the following problems.
That is, in the case of the image reading apparatus shown in FIG. 3 described above, the upper surface of the original 201 is read by the first CIS 204 and the second
Of the original 201 is read by the CIS 209.

At this time, if the first CIS 204 and the second CIS 2
When reading the same line on both sides at the same time by disposing 09 opposite each other, the light on both sides of the document 201 is illuminated, and the data of the document 201 on the opposite side of the surface to be read is shown off. Occurs.

For this reason, the arrangement of the first CIS 204 and the second CIS 209 is slightly shifted as shown in FIG.
Of the same line is not read at the same time.
In such an arrangement, the start of reading the lower surface of the document 201 is delayed by several lines from the upper surface.

As a result, the preview screen displayed on the monitor 316 is displayed with a delay on the lower surface.
The fact that the preview screens on both sides are not displayed at the same time in spite of the same original has a problem of giving an unnatural impression.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to be able to simultaneously display the same line on both sides of a document on a preview screen.

[0020]

According to the present invention, there is provided an image reading apparatus comprising: a document reading section for reading both sides of a document to generate image data; and a storage section for storing the image data generated by the document reading section. Writing / reading control means for controlling an operation of writing the image data to the storage unit and an operation of reading the image data from the storage unit; and detecting a timing at which the original reading unit reads the front and back surfaces of the original. A reading timing detecting unit, wherein when the timing of starting reading of the front side and the back side of the original is different, from the start of reading of one original side to the start of reading of the other original side The image data obtained during is stored in the storage unit. According to another feature of the image reading apparatus of the present invention, a document reading unit that reads both sides of a document to generate image data, and a reading timing detecting unit that detects timing of reading the front and back sides of the document An A / D converter for converting image data generated by the document reading unit from analog data to digital data; and an image processing including at least density correction for the image data digitized by the A / D converter. An image processing unit for performing image processing, a storage unit for storing image data on which predetermined image processing has been performed by the image processing unit, an operation of writing the image data to the storage unit, and reading the image data from the storage unit Write / read control means for controlling operation;
An image data output unit that transfers the image data read from the storage unit to an external device, and a timing to start reading the front surface of the document and a timing to start reading the back surface of the document are different In this case, image data obtained from the start of reading of one document surface to the start of reading of the other document surface is stored in the storage unit. Other features of the image reading apparatus of the present invention include an LED for irradiating the document, a lens for condensing light reflected from the document, and a plurality of photodiodes arranged in one line. A first reading unit configured to include a sensor array and a transparent plate with which the document comes into contact, and a first and second contact type line image sensors for reading the document line by line; If the image sensor and the second contact-type line image sensor have different timings to start reading the front and back surfaces of the document, the reading of one document surface is started and then the reading of the other document surface is started. While storing the image data obtained until the reading is started in the storage unit,
The image data of the same line on the front and back sides of the document is read out from the storage means for every predetermined number of lines and output alternately. Another feature of the image reading apparatus of the present invention is that two sets of charge-coupled devices are used instead of the two sets of contact type line image sensors.

The image reading method according to the present invention comprises: a document reading process for reading both sides of a document to generate image data; a storage process for storing image data generated by the document reading process in a storage unit; In the reading process, a reading timing detecting process for detecting a timing for reading the front and back surfaces of the document, an operation for writing the image data to the storage unit, and a writing / controlling operation for reading the image data from the storage unit.
In the reading control process and the document reading process,
A reading timing detection process for detecting a timing of reading the front and back sides of the original, wherein the reading of the front side and the back side of the original is different when reading the front side and the back side of the original is different. Is stored in the storage unit from the start of the reading to the start of reading of the other document surface. Another feature of the image reading method of the present invention is that a document reading process for reading both sides of a document to generate image data, and that the image data generated by the document reading process is converted from analog data to digital data. A / D conversion processing for converting the image data into digital data, image processing for performing processing including at least density correction on the image data digitized by the A / D conversion processing, and a storage unit for storing the image data subjected to the image processing. A write / read control process for controlling an operation of writing the image data to the storage unit and an operation of reading the image data from the storage unit; and a process of storing the image data read from the storage unit. An image reading method for performing image data output processing for transferring to an external device, wherein reading of the front and back surfaces of the document is started. When the timings are different, image data obtained from the start of reading of one document surface to the start of reading of the other document surface is stored in the storage unit.

The storage medium of the present invention is characterized by storing a program for causing a computer to function as each of the above means. Another feature of the storage medium of the present invention is that a program for causing a computer to execute the procedure of the image reading method is stored.

[0023]

Since the present invention has the above-mentioned technical means, a storage unit for storing image data generated by the original reading unit is provided. Since the image data obtained from the start of the reading of the original to the start of the reading of the other original is stored in the storage unit, the timing of starting the reading of the front and back of the original is different. However, it is possible to alternately output the data of the same line on both sides of the document by compensating for the difference in the read start timing. Further, since the storage unit for storing the image data is incorporated, there is obtained an advantage that the storage unit of the external device is not affected by the state of the external device or the capacity of the storage unit.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a first embodiment of an image reading apparatus, an image reading method and a storage medium according to the present invention. In each of the components in FIG. 1, the same components as those shown in FIG. 4 described in the related art are denoted by the same reference numerals, and detailed description of the operations will be omitted. The image reading apparatus of FIG. 1 is different from the image reading apparatus of FIG. 4 in that an offset RAM 101 and an offset correction circuit 102 are added.

As described above, the timing of starting reading of the original 201 is different between the front and back sides of the original 201, but here, the first CIS 204 is n (n = 2, 3,
4, ...., n) Assume that reading has started earlier by the number of lines. In this case, the image data in the first CIS 204 is n
The data is temporarily stored in the offset RAM 101 for the number of lines.
The writing and reading of the offset RAM 101 are controlled by an offset correction circuit 102.

The operation of the offset correction circuit 102 will be described with reference to the timing chart of FIG. In FIG. 2, HSYNC is a synchronization signal for each line of the first CIS 204 and the second CIS 209, and the reading position moves to the next line every time a pulse is given.

CSCLK-A is a drive pulse for the data output section of the first CIS 204 in FIG. 1, and outputs the accumulated image data of the previous line. Similarly, CSCLK-B is the second CI
It is a drive pulse of the data output part of S209.

OUT-A is the output signal of the first CIS 204,
A means the data of the first line, and the following 2 and 3
Continue with the line. Similarly, OUT-B is the output data of the second CIS 209, and 1-B means the data of the first line.

SEL is a pulse for switching the selector 305 in FIG. SELOUT is the output of the selector 305, and conventionally, the computer 31
4 had been forwarded.

WR-A is a write pulse for writing the output signal OUT-A of the first CIS 204 into the offset RAM 101. WR-ADDRESS is an address for writing to the offset RAM 101, and 1-A indicates a plurality of addresses for storing data of the first line.

RE-A is the OU written to the offset RAM 101
This is a read pulse for reading TA data.
-ADDRESS is a plurality of addresses when data is read from the offset RAM1O1.

By controlling the reading and writing of the offset RAM 1O1 at the timing shown in FIG. 2, the data of the same line on the front surface and the back surface is alternately output to DATAOUT which is the output of the offset correction circuit 102 in FIG. Is done. That is, data on the same line on both sides is alternately output to the computer 314 as an external device. Therefore, according to the above operation, the offset RAM 101 needs a capacity capable of storing at least data for n lines.

The first CIS 204 and the second CIS 204 shown in FIG.
Instead of CIS 209, a charge coupled device CCD may be used.
Further, the shading RAM 307, the offset RAM 101, and the buffer RAM 311 do not necessarily need to be provided with three RAMs, and may be shared by one RAM.

(Other Embodiments of the Present Invention) The present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), and is applied to an apparatus composed of one device. May be applied.

Further, the functions of the above-described embodiments are implemented in an apparatus connected to the above-described various devices or a computer in a system so that various devices are operated so as to realize the functions of the above-described embodiments. Supplies the software program code for performing the
The invention implemented by operating the various devices according to the program stored in U) is also included in the scope of the present invention.

In this case, the program code of the software implements the functions of the above-described embodiment, and the program code itself and means for supplying the program code to a computer, such as the program The storage medium storing the code constitutes the present invention. As a storage medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-RO
M, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the supplied program code, not only the functions of the above-described embodiment are realized, but also the OS (operating system) or other operating system in which the program code runs on the computer. Needless to say, such program code is also included in the embodiment of the present invention when the functions of the above-described embodiment are realized in cooperation with the application software or the like.

Further, after the supplied program code is stored in a memory provided in a function expansion board of the computer or a function expansion unit connected to the computer, the function expansion board or the function expansion unit is specified based on the instruction of the program code. The present invention also includes a case where a CPU or the like provided in the apparatus performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0039]

According to the present invention, when the timing of starting reading of the front side and the back side of the original is different, reading of one original side is started and then reading of the other original side is started. Since the image data obtained during this period is held, it is possible to compensate for the difference in reading timing between the front and back sides of the document, and to output the data of the same line on both sides of the document to an external device alternately. As a result, the front and back sides of the document can be simultaneously displayed on the preview screen, and a more natural preview display can be realized. In addition, since the storage unit for storing the image data is built in, the state of the external device and the capacity of the storage unit of the external device are not affected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of an image reading apparatus according to the present invention.

FIG. 2 is a diagram showing operation timing of the image reading apparatus according to the present invention.

FIG. 3 is a diagram illustrating a mechanism of a main part of the image reading apparatus.

FIG. 4 is a block diagram illustrating a circuit configuration of a conventional image reading apparatus.

[Explanation of symbols]

 102 Offset correction circuit 101 Offset RAM 204 First contact line image sensor (CIS) 209 Second contact line image sensor (CIS) 303 A / D conversion circuit 304 A / D conversion circuit 306 Shading correction circuit 312 Interface circuit

Claims (8)

[Claims] An original reading unit configured to read both sides of an original to generate image data; a storage unit configured to store image data generated by the original reading unit; an operation of writing the image data to the storage unit; And writing / reading control means for controlling an operation of reading the image data from the storage unit, wherein when reading of the front side and the back side of the original is started at a different time, reading of one of the original sides is started. An image reading apparatus characterized by storing image data obtained during a period from when the reading is performed until the reading of the other document surface is started in the storage unit. 2. An original reading unit that reads image data by reading both sides of an original, an A / D converter that converts the image data generated by the original reading unit from analog data to digital data, An image processing unit that performs image processing including at least density correction on the image data digitized by the / D converter; a storage unit that stores image data that has been subjected to predetermined image processing by the image processing unit; Write / read control means for controlling an operation of writing the image data to the storage unit and an operation of reading the image data from the storage unit; and an image data output for transferring the image data read from the storage unit to an external device And a timing to start reading the front side of the document and a timing to start reading the back side of the document The image data obtained from when the reading of one document surface is started until the reading of the other document surface is started is stored in the storage unit. Reader. 3. An LED for irradiating the document, a lens for condensing light reflected from the document, a sensor array in which a plurality of photodiodes are arranged in a row, and a transparent plate with which the document contacts. And the first and second contact-type line image sensors for reading the document line by line constitute the document reading unit. The first contact-type line image sensor and the second contact-type line image sensor However, if the timing to start reading the front and back sides of the original is different,
From the start of reading one document surface to the start of reading the other document surface, storing the image data obtained in the storage unit, the surface of the document,
3. The image reading apparatus according to claim 2, wherein the image data of the same line on the back side is read out from the storage means every predetermined number of lines and output alternately. 4. The image reading apparatus according to claim 3, wherein two sets of charge-coupled devices are used instead of the two sets of contact type line image sensors. 5. A document reading process for generating image data by reading both sides of a document, a storage process for storing image data generated by the document reading process in a storage unit, and storing the image data in the storage unit. An image reading method for performing a writing operation and a writing / reading control process for controlling an operation of reading out the image data from the storage unit, wherein the timing to start reading the front side and the back side of the original is different. An image reading method for storing image data obtained from the start of reading of one original surface to the start of reading of the other original surface in the storage unit. 6. An original reading process for generating image data by reading both sides of an original, an A / D conversion process for converting the image data generated by the original reading process from analog data to digital data, Image processing for processing image data digitized by the / D conversion processing by performing image processing including at least density correction, storing the image-processed image data in a storage unit, and storing the image data in the storage unit. A write / read control process for controlling an operation of writing the image data and an operation of reading the image data from the storage unit; and an image data output process of transferring the image data read from the storage unit to an external device. An image reading method to be performed. Image reading method and to store the reading of the document surface is started, the image data obtained until the reading of the other document surface is started in the storage unit. 7. A storage medium storing a program for causing a computer to function as each of the means according to claim 1. Description: 8. A storage medium storing a program for causing a computer to execute the procedure of the image reading method according to claim 5 or 6.