JP2001157001A - Image reader and image reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader and an image reading method for speedily changing a mode, even if reading mode is changed with the change of index period. SOLUTION: This image reader has an image read means for converting the image of an original into an electrical signal and reading it, a signal- processing means for processing the electrical signal, a setting data collection means for collecting plural pieces of setting data used in a signal processing and a setting data storage means storing plural pieces of setting data. The collection operation and the storage operation of plural pieces of setting data are previously executed, after the power of the reader is supplied. When the index period is switched, respective pieces of setting data stored in the setting data storage means are read sequentially and setting data is set.

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 and an image reading method for reading an original image using a photoelectric conversion element, and more particularly, to an image reading method capable of shortening an original reading time when an index cycle is switched. The present invention relates to a reading device and an image reading method.

[0002]

2. Description of the Related Art Image reading apparatuses are widely used as image input apparatuses such as image scanners in computer systems and input apparatuses for copying machines and facsimile machines. Such an image reading apparatus uses a photoelectric conversion element as an image reading means, performs a photoelectric conversion operation, and reads an image by converting an image of various originals or the like into an electric signal. An image reading apparatus using a one-dimensional image sensor such as a one-dimensional CCD as an image reading means has a relatively high resolution and can be operated at a high speed, and thus has become mainstream.

FIG. 5 shows a flow of operation in a conventional image reading apparatus. When performing image reading, as shown in FIG.
First, initialization a1 such as a change of a timing signal or movement of a home position is performed, and then, offset and gain are adjusted, and data collection a2 such as white data collection and black data collection is performed. The reading operation a3 is performed. In this reading operation, the index cycle, which is the reading cycle of one line in the main scanning direction, is constant.

[0004] Next, when the resolution of the image reading device is switched, for example, when the resolution in the main scanning direction is switched to 600 dpi for a one-dimensional image sensor of 400 dpi, it is necessary to interpolate the data during that period. Become. Therefore, when the index cycle is switched by switching from the a mode to the b mode as shown in FIG. 5, the initialization b such as the change of the timing signal and the movement of the home position is performed in accordance with the change of the index cycle.
1 to adjust the offset and gain, and further perform data collection b2 such as white data collection and black data collection.
Thereafter, reading b3 of the document image is performed.

[0005]

As described above, in the conventional image reading apparatus, when the index cycle is switched for switching the resolution or the like, it is necessary to perform data collection and setting corresponding to the switched index cycle. was there.
Since it takes time to collect and set data, in the example of FIG.
It took a long time until the start of No. 3 and quick switching was not possible, image reading after switching was delayed, and the operability of the image reading apparatus was deteriorated.

In view of the above-mentioned problems of the prior art, the present invention shortens the time until the start of the original image reading operation after the change of the resolution or the like, and quickly reads the original image. It is an object of the present invention to provide an image reading apparatus and an image reading method in which the operability of image reading is improved.

[0007]

In order to achieve the above object, an image reading apparatus according to the present invention comprises: an image reading means for converting an image of a document into an electric signal for reading; and a signal processing means for processing the electric signal. Means for collecting a plurality of setting data used in performing the signal processing, and a setting data storage means for storing the plurality of setting data, and an operation of collecting the plurality of setting data. And the storage operation is performed in advance after the power is turned on.

According to this image reading apparatus, the collection and storage of a plurality of setting data are executed in advance after the power of the apparatus is turned on. Therefore, it is not necessary to collect and store the setting data every time an image of a document is read. The time until the start of the image reading operation can be reduced. Therefore, it is possible to quickly read the document image and improve the operability of the image reading.

According to another aspect of the present invention, there is provided an image reading device for converting an image of a document into an electric signal and reading the image.
Signal processing means for performing signal processing on the electric signal, setting data collecting means for collecting a plurality of setting data used in performing the signal processing, and setting data storage means for storing the plurality of setting data. Performing a collection operation and a storage operation of the plurality of setting data in advance after power-on, respectively, and when an index cycle is switched, sequentially reads out the setting data stored in the setting data storage means, It is characterized in that setting data is set.

According to this image reading apparatus, collection and storage of a plurality of setting data are executed in advance after the apparatus is powered on,
There is no need to collect and store setting data when the index cycle is switched for switching resolution etc.
It is possible to shorten the time until the reading operation of the original image is started.
Therefore, it is possible to quickly read the document image and improve the operability of the image reading.

Further, the image reading method of the present invention is used in performing an image reading step of converting an image of a document into an electric signal and reading the same, a signal processing step of processing the electric signal, and a signal processing. A setting data collecting step of collecting a plurality of setting data, and a setting data storing step of storing the plurality of setting data, wherein the setting data collecting step and the setting data storing step are performed in advance before the image reading step. It is characterized by executing.

According to this image reading method, the collection and storage of a plurality of setting data are executed in advance before the image reading step, so that it is not necessary to collect and store the setting data every time the image of the document is read. It is possible to shorten the time until the reading operation of the original image is started. Therefore, it is possible to quickly read the document image and improve the operability of the image reading.

Further, the setting data collecting step and the setting data storing step can be executed in advance after power is turned on.

Further, another image reading method according to the present invention comprises an image reading step of converting an image of a document into an electric signal and reading the image.
A signal processing step of performing signal processing on the electrical signal, a setting data collecting step of collecting a plurality of setting data used in performing the signal processing, a setting data storing step of storing the plurality of types of setting data, A data setting step of setting a plurality of setting data, the setting data collecting step and the setting data storing step are executed in advance after power is turned on, and when the index cycle is switched, the stored plurality of stored data are stored. The setting data is sequentially read out, and the data setting step is executed.

According to this image reading method, collection and storage of a plurality of setting data are executed in advance after the power of the apparatus is turned on,
There is no need to collect and store setting data when the index cycle is switched for switching resolution etc.
It is possible to shorten the time until the reading operation of the original image is started.
Therefore, it is possible to quickly read the document image and improve the operability of the image reading.

Further, after the data setting step, the image reading step can be executed a plurality of times corresponding to the plurality of setting data.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view schematically showing a mechanical configuration of an image reading apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram of the image reading apparatus of FIG. 1, and FIG. FIG. 4 is a timing chart of each signal in the image reading apparatus of FIG. 1, and FIG. 4B is a diagram showing a normalized image signal.

As shown in FIG. 1, an image reading apparatus includes an illumination lamp (eg, a halogen lamp) as a means for illuminating a document.
A document table 33 such as a glass plate as means for supporting a document 32 as an object to be read; a one-dimensional image sensor 35 such as a one-dimensional CCD as image reading means;
A lens 34 which is a unit for condensing the reflected light from the light source 2 on the one-dimensional image sensor 35.

As shown in FIG. 2, the image reading apparatus further includes an analog signal processing unit for receiving an electric signal converted by the one-dimensional image sensor 35 based on the image of the document 32 and performing noise removal and amplification. 41, an AD converter 42 for converting a signal from the analog signal processor 41 to a digital signal, a shading corrector 43, a timing signal generator 44 for controlling the operation of the entire circuit, and a central processing unit (CPU) 45. And a RAM 46 as setting data storage means for storing setting data and the like, and has a plurality of resolution modes.

[0020] The image reading apparatus is one in the main scanning direction.
By electrical scanning by the three-dimensional image sensor 35,
In the sub-scanning direction, an image is read from the original 32 by mechanical scanning such as movement of the original or the carriage.

The analog signal processing section 41 has an adjustment value setting section 411 for setting various adjustment values such as an offset adjustment value and a gain adjustment value used in analog signal processing. Also,
The shading correction unit 43 includes a reference data setting unit 431 that sets various reference data such as white level reference data and black level reference data for shading correction.

The analog signal processing section 41, the AD conversion section 42, and the shading correction section 43 constitute signal processing means for processing an electric signal as an image reading signal. Also, various adjustment values such as offset adjustment values and gain adjustment values and various reference data such as white level reference data and black level reference data for shading correction are set as setting data before the actual reading operation in the image reading apparatus. Is the data set in

Further, various adjustment values such as an offset adjustment value and a gain adjustment value, and a group of data such as white level reference data and black level reference data for shading correction are set as one set data in the image reading apparatus. This is data set before the reading operation. One-dimensional image sensor 35, analog signal processing unit 41, AD conversion unit 42
The CPU 45 constitutes a data collecting means for collecting the above-mentioned setting data. The data collecting means can collect a plurality of setting data corresponding to a plurality of index periods and store the plurality of setting data in the RAM 46, respectively.

That is, for the purpose of shading correction, one line of white level reference data and one line of black level reference data are collected before reading a document, and the respective data are stored in the RAM 46. Further, the offset voltage and gain in the amplifier circuit in the analog signal processing unit 41 are adjusted, and various adjustment values such as the adjusted offset adjustment value and gain adjustment value are stored in the RAM 46. And
When reading the original image, the setting data such as the white level reference data and various adjustment values stored in the RAM 46 is read out, and the reference data setting unit 431 and the adjustment value setting unit 411 are read.
Set to each.

One set data such as the offset voltage adjustment value, the gain adjustment value, the white level reference data and the black level reference data needs to be determined for one index cycle. That is, when the resolution is changed, the index cycle changes and the accumulation time of the image sensor 35 changes, so that the output level of the analog signal from the image sensor 35 also changes. Accordingly, it is necessary to readjust the offset voltage adjustment value and the gain adjustment value of the analog signal processing unit 41. Furthermore, white level reference data,
The black level reference data also needs to be collected again.

In this embodiment, when the image reading apparatus has, for example, a mode A with a resolution of 400 dpi and a mode B with a resolution of 600 dpi, even if the index cycle is switched during use, the image reading apparatus can immediately operate at the resolution after the switching. As shown in FIG. 3, initialization and data collection are performed a plurality of times in advance.

The operation of the whole circuit shown in FIG. 2 is controlled by a timing signal output from the timing generator 44. Further, the CPU 45 sends a timing signal and an instruction signal for initialization for setting a home position and an instruction for each adjustment to each block in FIG. Specifically, the analog signal processing unit 41 is instructed to perform offset adjustment and gain adjustment, the timing generation unit 44 is instructed to set timing according to the index period, and the shading correction unit 43 is instructed. To collect white level and black level,
An instruction such as storage in M46 is issued.

Next, referring to FIG. 4, the shading correction section 43 for performing the shading correction processing will be described.
FIG. 4A shows a timing chart of the main scanning, and each signal is synchronized with the pixel clock. One main scanning period is started by the index signal, and image signals are sequentially output from the first pixel of the one-dimensional image sensor 35. This image signal is output in a range wider than the width of the document. Valid period of image in this image signal (original area)
Is the range of the main scanning effective area signal shown in FIG.

The image signal shown in FIG. 4A is a one-line image signal output when a white uniform correction reference original is read and all pixels for one line are white and uniform.
The levels are not uniform and there is considerable distortion. This distortion is due to variations in the sensitivity of the sensor element and dimming around the optical system, and high-quality reading cannot be performed as it is. For this reason, the white level reference data for each pixel read from the white level reference plate is set in the reference data setting unit 431 in FIG. 2, and the correction is performed by dividing the read data by the white level reference data when reading the original. Then, data normalized as an image signal having a constant output level as shown in FIG. 4B can be obtained.

Further, in the one-dimensional image sensor 35, even when all the pixels are black, an offset is generated due to a dark current or the like, and therefore, it is necessary to correct the offset voltage. For this reason, the black level reference data is similarly obtained and set in the reference data setting unit 431 in FIG. 2, and the offset voltage is corrected based on the black level reference data.

The operation of the image reading apparatus will be described with reference to FIGS. As shown in FIG. 3, first, the power of the image reading apparatus is turned on, and after entering an idling state, each block of FIG. 2 is initialized A1 for setting a timing signal and a home position corresponding to the A mode. Is performed, and a data collection A2 such as a gain adjustment value, white level reference data, and black level reference data is performed in the index cycle of the A mode, and the setting data is stored. Next, similarly, initialization B1 is performed corresponding to the B mode, data collection B2 is performed at the index cycle of the B mode, and the setting data is stored.

When reading the original image A3 in the A mode after the above operation is completed, the setting data is set to R
The data is read from the AM 46 and set in the adjustment value setting unit 411 of the analog signal processing unit 41 and the reference data setting unit 431 of the shading correction unit. The illumination lamp 31 illuminates the original 32 supported on the original platen 33, and the light reflected from the original 32 is condensed by the lens 34,
An optical signal for one main scanning line is incident on the one-dimensional image sensor 35. The optical signal for one line enters the one-dimensional image sensor 35 for a predetermined accumulation time, is photoelectrically converted, and is converted into an electric signal. One-dimensional image sensor 35
Stores electrical signals for the number of pixels in the main scanning direction.
The stored data is read out sequentially for each pixel,
The signal is sent to the analog signal processing unit 41. In this manner, one line in the main scanning direction is read at a constant index cycle.

The analog signal processor 41 removes noise from each pixel signal and amplifies the signal. The analog signal that has been subjected to the analog processing in this manner is supplied to the AD conversion unit 42.
And converted to a digital signal. This digital signal is sent to the shading correction unit 43, and after performing shading correction processing, is sent to the next-stage image processing unit (not shown).

When this series of operations is completed for one line, sub scanning is performed by moving the original table 33 or the optical system in the sub scanning direction in FIG. 1 to mechanically read the next line. The subject moves. By repeating this operation, a two-dimensional image of the entire document is read, and an image signal is generated. The image signal is sent to an image processing unit (not shown), and is sequentially processed.

Next, when the mode is switched to the B mode after the image reading in the A mode is completed, the setting data for the B mode is read from the RAM 46, and the adjustment value setting section 411 of the analog signal processing section 41 is read out. These are set in the reference data setting unit 431 of the shading correction unit. Thereafter, reading B3 in the B mode is performed in the same manner as described above.

As described above, according to the present embodiment, a plurality of setting data corresponding to a plurality of resolutions (index periods) are collected and stored in advance after the apparatus is powered on, and are stored in accordance with each resolution. Since the setting data stored at the time of reading is read and set, a time-consuming setting data collecting operation is not required each time, so that the image reading operation after switching the resolution can be performed very quickly. As a result, the operability of the image reading apparatus capable of reading at a plurality of resolutions is extremely improved, and the apparatus is easy to use.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to these embodiments.
Various modifications are possible within the scope of the technical idea of the present invention. For example, FIG. 3 shows a case where the resolution is switched between two types, but it goes without saying that there may be three or more types. Although the collected setting data is stored in the RAM 46, a memory unit such as a RAM may be provided in the analog signal processing 41 and the shading correction unit 43, and may be stored separately.

[0038]

According to the present invention, even when the index period is changed due to a change in resolution or the like, the time until the start of the original image reading operation after the change is reduced, and the original image can be read quickly. By doing so, it is possible to provide an image reading apparatus and an image reading method with improved image reading operability.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an operation of an image reading apparatus according to an embodiment of the present invention in a time series.

FIG. 2 is a perspective view schematically showing a mechanical configuration of a main part of the image reading apparatus of FIG. 1;

FIG. 3 is a block diagram of the image reading apparatus of FIG. 1;

4A is a timing chart of each signal in the image reading apparatus of FIG. 1, and FIG. 4B is a diagram showing a normalized image signal.

FIG. 5 is a diagram showing the operation of the conventional image reading apparatus in time series.

[Explanation of symbols]

REFERENCE SIGNS LIST 31 illumination lamp 32 document 33 document table 34 lens 35 one-dimensional image sensor 41 analog signal processing unit 411 adjustment value setting unit 42 AD conversion unit 43 shading correction unit 431 reference data setting unit for shading correction 44 timing signal generation unit 45 central processing Device (CPU), 46 RAM

Claims (6)

[Claims] An image reading unit that converts an image of a document into an electric signal and reads the electric signal; a signal processing unit that performs signal processing on the electric signal; and a setting that collects a plurality of setting data used in performing the signal processing. An image reading apparatus comprising: a data collection unit; and a setting data storage unit configured to store the plurality of setting data, wherein an operation of collecting and storing the plurality of setting data is performed in advance after power-on, respectively. apparatus. 2. An image reading unit that converts an image of a document into an electric signal and reads the electric signal, a signal processing unit that performs signal processing on the electric signal, and a setting that collects a plurality of setting data used in performing the signal processing. A data collection unit; and a setting data storage unit that stores the plurality of setting data, wherein the collection operation and the storage operation of the plurality of setting data are performed in advance after power-on, respectively. An image reading device for sequentially reading out each of the setting data stored in the setting data storage means and setting the setting data. 3. An image reading step of reading an image of a document by converting the image into an electric signal; a signal processing step of processing the electric signal; and a setting for collecting a plurality of setting data used in performing the signal processing. A data collecting step; and a setting data storing step of storing the plurality of setting data, wherein the setting data collecting step and the setting data storing step are performed in advance before the image reading step. Image reading method. 4. The setting data collecting step and the setting data storing step are performed in advance after power is turned on.
2. The image reading method according to 1. 5. An image reading step of reading an image of a document after converting the image into an electric signal, a signal processing step of processing the electric signal, and a setting for collecting a plurality of setting data used in performing the signal processing. A data collecting step, a setting data storing step of storing the plurality of setting data, and a data setting step of setting the plurality of setting data, wherein power is supplied to the setting data collecting step and the setting data storing step. An image reading method, which is executed in advance later, and when the index cycle is switched, the stored setting data is sequentially read out and the data setting step is executed. 6. The image reading method according to claim 5, wherein, after the data setting step, the image reading step is executed a plurality of times in accordance with the plurality of setting data.