JP2001257848A - Image scanning apparatus and method and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the processing time of preprocessing for starting a scanning of an image. SOLUTION: The device is equipped with a light quantity control means which controls the light quantity of a light source for generating a reflected or transmitted optical image by irradiating a document placed on a platen when the kind of the document is switched and a white shading correcting means which corrects the white shading level of an image signal generated from an optical image of the document when the light quantity-control means performs the light quantity control; when the kind of the document place on the platen is not switched, the preprocessing time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image reading device,
The image reading method and the storage medium are particularly suitable for use in an image reading apparatus for reading a reflection optical image or a transmission optical image of a document placed on a document table.

[0002]

2. Description of the Related Art Conventionally, an image scanner using a linear image sensor (hereinafter referred to as CCD) has been known as an image reading apparatus. 2 (a) and 2 (b) simply show a general hardware configuration of an apparatus called a flatbed type scanner. FIG. 2 (a) is a top view and FIG. ) Is a side view.

In FIG. 2A and FIG. 2B, reference numeral D denotes a read original placed on an original platen glass 100.
Folded by 3,104, C by lens 105
An image is formed on the CD 106.

A light source 101 and mirrors 102, 103, 1
The reading unit 107 on which the lens 104, the lens 105, and the CCD 106 are fixedly mounted is moved in parallel with the platen glass 100, and, for example, is scanned from left to right in FIG. 1
得 る Obtain an image signal for one page. The CCD 106 board 113 on which the CCD 106 is mounted and the main board 112 fixed on the image reading apparatus main body side are connected to a cable 11.
1 connected.

As shown in FIG. 2A, the direction from top to bottom is the main scanning direction, and the direction from right to left is the sub-scanning direction. The interior is shielded from light by the exterior cover 1 and the document holder 110 in order to avoid the influence of external light.

FIGS. 3 (a) and 3 (b) schematically show an example of a configuration when a transparent original reading unit for reading a transparent original by a flatbed type scanner is mounted. Is a top view and FIG. 3B is a side view.

In FIG. 3A, light sources 115 and 116 are used.
The light emitted from the light guide plate 113 plays a role of causing the transparent original to function as a uniform surface light source by the light guide plate 113 (see FIG. 2). In FIG. 3, reference numeral 117 denotes the light source 1
An inverter for turning on lights 15 and 116. Lighting / turning off and dimming control from the main board 112 are performed by a control signal through a cable 118.

FIG. 4 shows a general configuration example of a circuit block capable of adjusting the output level. Light emitted from the light source 101 whose dimming can be controlled is reflected by a reflection original, and the reflected light is imaged on the CCD 106 via the lens 105.

The image signal is generated by photoelectric conversion by the CCD 106, and the image signal is processed by the analog processing circuit 31. Next, the analog signal is digitized by the A / D converter 32.

The signal is sequentially sent to the shading correction circuit 3 and the image processing circuit 4 to perform predetermined signal processing. The image signals output from the image signal processing circuit 4 are sequentially output while performing transmission and reception with the host computer 9 by the I / F controller 8. The I / F controller 8 is controlled by the CPU 36.

The peak output circuit 5 detects the peak output in the area designated by the CPU 36 and stores the peak output. Further, the amount of light of the light source 101 can be controlled from the CPU 36 via the reflective document lamp dimming control circuit 6.

In FIG. 4, the means for controlling the dimming of the lamp 101 is described as the output control means. However, the storage time control means for the CCD 106, the electronic shutter control means, the analog processing circuit 31, Not A / D
It is possible to use various means such as a gain adjusting means by the ref control of the converter and a level adjusting means in the image processing circuit 4. However, more S /
In order to obtain an image with a good N, it is most effective to use the dimming control as shown in FIG.

Referring to FIG. 4, when reading a transparent original, light signals emitted from light sources 115 and 116 which can be dimmed are formed on a CCD 106 via a lens 105.

The amount of light from the light sources 115 and 116 is controlled by the CPU 36 through the lamp dimming control circuit 7 for the transparent original. As shown in FIG. 4, when a lamp such as the reflection document lamp 101 and the transmission document lamp 115 has independent lamps depending on the type of the document to be read, the lamps are not turned on at the same time and are used simultaneously. The CPU 36 controls the I / F controller 8 in accordance with the instruction of the type of the original to be read.

FIG. 5 shows a flowchart relating to an image reading procedure as an example of controlling an output level by an optical signal by dimming control. As shown in FIG. 5, in a first step S101, the light source 101 is checked by the host computer 9 to check the lamp of the original to be read, for example, the light source 101 when the reading of the reflection original is instructed.

Usually, a light source includes a cold cathode lamp, a halogen lamp, and the like, and dimming control includes voltage control, current control, intermittent lighting control, and the like. Generally, PWM control is usually performed in the lamp dimming control circuit.

Next, in step S102, a wait time of 10 seconds is provided to wait for the light amount of the light source 101 to be stably turned on. This wait time also depends on the performance of the lamp and the configuration of the image reading apparatus. Because it is not constant.

In step S103, the light output peak level detection circuit 5 detects the light output level Pn in order to maintain the stability of the light source 101, until the target output level Pt is reached, or around the output level Pt. In the dimming control in step S104, the target Pt is set at ± 1% until the value falls within the range.

Next, in step S105, it is determined whether or not the target Pt ± 1% has been reached. If the result of this determination is that it has not been reached, the process proceeds to step S106,
Constant time (Wait time is 0.75 s in this example)
stand by.

In order to finally wait for the light quantity to stabilize,
After the Wait time in step S107, step S1
At 08, it is determined whether or not the output levels Pn continuously match. As a result of the above determination, after the stability check, the lamp dimming control is ended. Next, white shading correction is performed in step S109, and step S11 is performed.
If 0, the image reading is executed and the process ends.

[0021]

Conventionally, in order to always read an image with a good S / N ratio, steps S102 to S108, which is a lamp light amount adjustment sequence, are performed without changing the type of a document to be read.
There is also a problem that step S109 for performing white shading correction is required for each scanning.

In the prior art, even if a lamp whose wait time greatly fluctuates depending on the environmental temperature, such as a cold cathode lamp, an image with good S / N is always obtained in response to various environmental changes. be able to.

However, since the processing from step S101 to step S109 for reading an image is required, there is a problem that much time is required until the image is read.

Further, in the prior art, when scanning is performed, even when the light source is sufficiently stable, all the processing procedures in accordance with the flowchart shown in FIG. 5 are executed, so that image reading is started. There was a problem that it took a lot of time to do so.

The present invention has been made in view of the above problems, and has as its object to reduce the processing time required before starting image reading.

[0026]

According to the present invention, there is provided an image reading apparatus for controlling a light amount of a light source for irradiating a document, and performing shading correction on an image signal generated from an optical image of the document. It is characterized by comprising shading correction means, and control means for operating the light quantity control means when the type of the document is changed, and thereafter operating the shading correction means. Another feature of the present invention is that a first light source for obtaining a reflection optical image of the original, a second light source for obtaining a transmission optical image of the original, and a first light source for the first light source. A first dimming unit for adjusting the light amount, a second dimming unit for adjusting the light amount of the second light source, and a plurality of photoelectric conversion elements for converting the reflection optical image or the transmission optical image of the document into a plurality of photoelectric conversion elements Photoelectric conversion means for accumulating signal charges in the first light source and outputting the image signals as image signals, and the first light control means or the second light control means when the first light source and the second light source are switched. And control means for operating. Another feature of the present invention is that when the first light control means or the second light control means is operated, a correction for operating a shading correction means for performing shading correction on the image signal is performed. It is characterized by having command means.

According to the image reading method of the present invention, there are provided a light amount control process for controlling a light amount of a light source for irradiating a document, a shading correction process for performing shading correction on an image signal generated from an optical image of the document, The method is characterized in that the light amount control process is executed when the type of the document is changed, and thereafter, the control process is executed to execute the shading correction process. According to another feature of the present invention, an image reading apparatus includes a first light source for obtaining a reflected optical image of a document and a second light source for obtaining a transmitted optical image of the document. A control method, comprising: a first method for adjusting a light amount of the first light source.
Dimming processing, a second dimming processing for adjusting the amount of light of the second light source, and a photoelectric conversion processing of photoelectrically converting a reflection optical image or a transmission optical image of the original and outputting the image as an image signal. When the first light source and the second light source are switched, a control process for executing the first dimming process or the second dimming process is performed. Another feature of the present invention is that, when the first dimming process or the second dimming process is executed, a correction command process for executing a shading correction process on the image signal is performed. It is characterized by.

A storage medium according to the present invention is characterized in that a program constituting each means described above is stored so as to be readable from a computer. According to another feature of the present invention, there is provided a storage medium storing a program for executing the above-described method so as to be readable from a computer.

[0029]

Since the present invention has the above technical means, only when the type of the original placed on the original platen is switched,
It is possible to perform the lamp light amount adjustment processing, and the preprocessing time for starting image reading can be significantly reduced.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an image reading apparatus, an image reading method and a storage medium according to the present invention will be described below. FIG. 1 shows an example of a flowchart of a procedure relating to image reading. In the following description, the configuration of the image reading apparatus according to the present embodiment will be described with reference to the block diagram of FIG. 4 used for describing the related art.

In the first step S201, it is determined according to an instruction from the host computer 9 whether the original to be read is a reflective original or a transparent original. That is, it is first determined whether the type of the document to be read has been changed. As a result of this determination, if the type of the original to be read has been changed, the process proceeds to step S202, and a lamp for the original to be read that is not simultaneously turned on, for example, if the reading of a reflective original is instructed, the light amount of the light source 101 is checked. Do.

Next, in step S203, a wait time of 10 seconds is provided to wait for the light amount of the light source 101 to stably light. The Wait time is not constant because it depends on the performance of the lamp and the configuration of the image reading device.

In step S204, the bright peak detection circuit 5 detects the bright output level Pn in order to stabilize the light quantity. Target target output level Pt
Or the light output is controlled to reach the vicinity of the target output level Pt.

In step S206, the target Pt ±
It is determined whether 1% has been reached. If the result of this determination is that the target level has not been reached, step S20
7 and a predetermined time (in this example, the wait time is set to 0.7
5s).

If the result of determination in step S206 is that the target level Pt has been reached, control proceeds to step S208. After the Wait time in step S208 elapses, in step S209, it is determined whether the output levels Pn continuously match. As a result of this determination, after confirming the stability check, the lamp dimming control is terminated, and the process proceeds to step S210.

In step S210, white shading correction is performed. Next, image reading is performed in step S211 and all processing ends.

If it is determined in step S201 that the type of the original to be read has not been changed, the light source 101
Since the light amounts of the light sources (or the light sources 115 and 116) are stable, the lamp light amount adjustment processing in steps S202 to S209 can be omitted. In that case,
In the white shading correction in step S210, sufficient image quality can be obtained with the data acquired when the type of the document to be read is changed. Therefore, it is not necessary to acquire the image again, and the image reading process in step S211 can be directly executed. It becomes possible.

That is, the lamps for the originals to be read (the reflective original lamps 101 or the transparent original lamps 115 and 116), which are not turned on at the same time, are connected to the host computer 9.
Only when the switching is performed in accordance with the instruction from, the processing from step S202 to step S210 may be performed. Therefore, according to the present embodiment, the waiting time for the second and subsequent image readings can be significantly reduced.

FIG. 6 shows an example of a computer system when each control means in the image reading apparatus of the present invention is configured as a program. In FIG. 6, 1200
Is a computer PC. The PC 1200 has a CP
U1201 that executes network printing device control software stored in the ROM 1202 or the hard disk (HD) 1211 or supplied from the floppy (registered trademark) disk drive (FD) 1212, and is connected to the system bus 1204. Control.

Reference numeral 1203 denotes a RAM, which functions as a main memory, a work area, and the like for the CPU 1201. Reference numeral 1207 denotes a disk controller (DKC), which is a hard disk that stores a boot program (a start program: a program for starting execution (operation) of a hardware or software of a personal computer), a plurality of applications, an edit file, a user file, a network management program, and the like. HD)
1211 and a floppy disk (FD) 1212.

Reference numeral 1208 denotes a network interface card (NIC) which controls the image reading apparatus of the embodiment by
It is used when connecting to a network via the AN 1220.

The CPU 1201 of the PC 1200 and the RO
The light amount control unit, the white shading correction unit, the first dimming control unit, the second dimming control unit, and the dimming control in the image reading apparatus of the present embodiment are executed by a program stored in the M1202 or the hard disk (HD) 1211. Command means, correction command means, and the like are configured.

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

Further, the functions of the above-described embodiment 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 embodiment. 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 software program code itself implements the functions of the above-described embodiment, and the program code itself and means for supplying the program code to a computer are provided.
For example, a storage medium storing such a program 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-ROM,
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 described in the above embodiments are realized, but also the OS (operating system) in which the program code runs on the computer. Alternatively, even when the functions described in the above-described embodiments are implemented in cooperation with other application software or the like, it goes without saying that such program codes are included in the embodiments of the present invention.

Further, after the supplied program code is stored in a memory provided in a function expansion board of a computer or a function expansion unit connected to the computer, the function expansion board or the function expansion unit is specified based on an 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.

[0048]

According to the present invention, as described above, according to the present invention, when the type of a document is switched, a light source for irradiating the document and generating a reflection optical image or a transmission optical image is provided. Since the light amount control is performed, the waiting time for the second and subsequent image readings can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of an external appearance of an image reading apparatus when reading a reflection original;

FIG. 3 is a diagram illustrating an example of an appearance of an image reading apparatus when reading a transparent original;

FIG. 4 is a block diagram illustrating an example of a control circuit of the image reading device.

FIG. 5 is a flowchart illustrating an example of a control procedure according to a conventional example.

FIG. 6 is a block diagram illustrating an example of a computer system that controls the image reading apparatus according to the embodiment.

[Explanation of symbols]

1200 Computer (PC) 1201 CPU 1202 ROM 1203 RAM 1204 System bus 1207 Disk controller (DKC) 1208 Network interface card (NI)
C) 1211 Hard disk (HD) 1212 Floppy disk (FD)

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H04N 1/401 H04N 1/40 101A F-term (Reference) 2H110 AA01 AA17 AA19 AA21 AC14 BA13 CD02 CD03 5B047 AA01 AA05 AB01 AB04 DA04 DB01 DC01 DC13 5C072 AA01 BA05 BA08 CA02 CA14 EA04 FB12 LA02 MB01 UA03 UA06 UA11 UA13 VA03 5C077 LL18 LL19 MM03 MM20 MM27 PP06 SS01 SS03

Claims (8)

[Claims] A light source control unit for controlling a light amount of a light source for irradiating a document; a shading correction unit for performing shading correction on an image signal generated from an optical image of the document; and a type of the document is changed. Control means for operating the light quantity control means in the case of the operation, and thereafter operating the shading correction means. 2. A first light source for obtaining a reflection optical image of a document, a second light source for obtaining a transmission optical image of the document, and a first light source for adjusting a light amount of the first light source. A light control means for adjusting the amount of light of the second light source, and a reflection optical image or a transmission optical image of the document stored in a plurality of photoelectric conversion elements as signal charges, Photoelectric conversion means for outputting as a signal; and control means for operating the first light control means or the second light control means when the first light source and the second light source are switched. An image reading apparatus, comprising: 3. The image processing apparatus according to claim 1, further comprising: a correction command unit that operates a shading correction unit that performs shading correction on the image signal when the first light control unit or the second light control unit is operated. The image reading device according to claim 2, wherein 4. A light amount control process for controlling a light amount of a light source for irradiating a document, a shading correction process for performing shading correction on an image signal generated from an optical image of the document, and a type of the document is changed. And a control process for executing the shading correction process after the light amount control process is performed. 5. A method for controlling an image reading apparatus, comprising: a first light source for obtaining a reflection optical image of a document; and a second light source for obtaining a transmission optical image of the document. A first dimming process for adjusting the amount of light of the first light source, a second dimming process for adjusting the amount of light of the second light source, and photoelectrically converting the reflection optical image or the transmission optical image of the document. A photoelectric conversion process of converting and outputting as an image signal; and a control for executing the first dimming process or the second dimming process when the first light source and the second light source are switched. And an image reading method. 6. The method according to claim 2, wherein when the first dimming process or the second dimming process is executed, a correction command process for executing a shading correction process on the image signal is performed. The image reading method described. 7. A storage medium storing a program constituting each means according to any one of claims 1 to 3 so as to be readable from a computer. 8. A storage medium storing a program for executing the method according to claim 4 in a manner readable from a computer.