JPH11220569A - Color image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color image reader, that attain white /black reading at a high speed, without degrading S/N ratio at a minimum light source luminance required for color reading. SOLUTION: Three R, G, B line sensor arrays with color filters and 4-th W line sensor array without a color filter constitute a CCD of the color image reader. A changeover switch 71 is placed between the W line sensor 63 and a G line sensor 65. The switch 71 is thrown to the position of the W line sensor 63 in the black/white read mode and thrown to the position of the G line sensor 65 in the case of the color read mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-line color line sensor provided with three color filters of red, green and blue, an analog processing unit for processing an analog output of the color line sensor, and an analog processing unit. The present invention relates to a color image reading apparatus having an A / D converter for converting analog data output from a section into digital data, and more particularly to a color image reading apparatus capable of monochrome output.

[0002]

2. Description of the Related Art In a color image reading apparatus that performs full-color reading in one scan, R (red), G
Generally, the apparatus is configured using a three-line CCD provided with respective color filters of (green) and B (blue).
Further, when performing monochrome reading with this color image reading apparatus, it is common to use a G output from which luminance information can be obtained most easily.

The S / N of image data depends on the CCD accumulation time (line cycle) and the amount of received light. To improve the S / N, increase the accumulation time or increase the amount of received light (light source brightness). Must be increased). Therefore, in the above-described color image reading apparatus, the same CCD accumulation time is required to perform monochrome reading with the same light source at the same S / N as in color reading, so that the reading speed of color reading and monochrome reading is the same. Would.

[0004]

A black-and-white printer generally has a higher printing speed than a color printer. However, as described above, when a monochrome image is read using the color image reading device at the same S / N as color reading, Since the reading speed at the time of black and white reading decreases, when this color image reading device is connected to a printer and printed out by the printer,
The printing speed will also decrease.

[0005] Under such circumstances, there has been a demand for improving only the monochrome reading speed without reducing the S / N. Here, a method of using a light source having a high luminance according to a required black-and-white reading speed and a required S / N is also conceivable.
Increasing the brightness of the light source is not preferable because it has problems of an increase in the size of the device, heat generation, and cost.

The present invention has been made in view of such a background, and a color image which can speed up black-and-white reading without lowering S / N with the minimum light source luminance required for color reading. It is an object to provide a reading device.

[0007]

In order to achieve the above object, the invention according to claim 1 comprises a three-line color line sensor provided with three color filters of red, green and blue, and a color line sensor. In a color image reading apparatus having an analog processing section for processing an analog output of a sensor and an A / D conversion section for converting analog data output from the analog processing section into digital data, a color filter is provided in addition to a color line sensor. Are provided, and a line sensor without color filters is added to form a line sensor composed of four lines as a whole.

[0008] In order to achieve the above object, a second aspect is provided.
According to the invention described in claim 1, in the invention according to claim 1, an analog output of a line sensor without a color filter and an analog output of a color line sensor are input, and switching means for selecting and outputting one of them is provided. And a selection signal for deciding whether to make a selection.

In order to achieve the above object, a third aspect of the present invention is provided.
According to the invention described in claim 2, in the invention described in claim 2, the analog output of the color line sensor input to the switching means is:
The color line sensor is characterized in that the sensitivity is the analog output of the color line sensor of the line having the closest value to the line of the line sensor without the color filter among the lines of the color line sensor.

[0010] In order to achieve the above object, the present invention relates to claim 4.
According to the invention described in claim 2, in the invention according to claim 2, a condition for performing color / black and white reading can be set from an external device connected by an interface, and color / black and white reading condition setting Control means for switching the selection signal in accordance with the above, controls the selection signal state so as to select a line with a color filter when color reading is set, and selects a line without a color filter when black and white reading is set. It is characterized by controlling the state of the selection signal.

According to the first aspect of the present invention, black-and-white reading is performed using a line sensor having no color filter, and black-and-white reading is speeded up with minimum light source luminance required for color reading without reducing S / N. Let it.

According to the second aspect of the present invention, one of the analog output of the line sensor without a color filter and the analog output of the color line sensor is selectively output, so that three sets of the output of the four line sensors are output. The device is composed of an analog processing unit and a digital conversion unit.

According to the third aspect of the present invention, the sensitivity between the line sensors to be switched is set to a close value, so that the analog processing unit can be configured with the same circuit (the addition of an amplification rate switching mechanism is not required).

According to the present invention, the line sensor selection control is automatically performed in accordance with a request from an external device.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a color image reading apparatus according to an embodiment of the present invention. This color image reading device includes a main body and an ADF mounted on the main body.

The main body includes a platen glass 1, a first mirror 2,
Illumination lamp 3, second mirror 4, third mirror 5, CCD
6, a traveling body motor 7, and other units shown in the following description. The ADF includes a document tray 8, a pickup roller 9, a registration roller pair 10, a transport drum 11,
Transport roller 12, transport roller pair 13, paper discharge roller pair 1
4, a paper discharge tray 32, and other units shown in the following description.

The original placed on the original platen glass 1 is
The light is emitted by an illumination lamp 3 integrally formed with the mirror 2, and the reflected light is scanned by the first mirror 2 and the second and fourth mirrors 4 and 5 integrally formed. afterwards,
The reflected light is converged by the lens 31, irradiates the CCD 6, and is photoelectrically converted. First mirror 2, illumination lamp 3,
The second mirror 4 and the third mirror 5 are movable in the double-headed arrow A direction by using the traveling body motor 7 as a drive source.

The originals stacked on the original tray 8 are picked up by a pickup roller 9, a pair of registration rollers 10, and a conveying drum 1.
1. The sheet is sent to a pair of conveying rollers 13 and a pair of sheet discharging rollers 14 via a reading position B by a conveying roller 12, and is discharged onto a sheet discharging tray 32.

When the document passes the reading position B,
The light is emitted by the illumination lamp 3 moved to the vicinity of the reading position B, and the reflected light is scanned by the first mirror 2, the second mirror 4 and the third mirror 5 integrally formed.
After that, the reflected light is focused by the lens 31 and the CCD 31
6 and is photoelectrically converted. The pickup roller 9 and the pair of registration rollers 10 are provided with a paper feed motor (not shown).
The transport drum 11, the transport roller 12, the transport roller pair 13, and the paper discharge roller pair 14 are driven by a transport motor (not shown).

At the reading position C, the contact image sensor 1
5 are installed. The contact image sensor 15 includes an LED (not shown) as a light source, a lens (not shown), and a sensor element (not shown). When the document passes the reading position C, the opposite surface (back surface) read at the reading position B is irradiated by a lamp in the contact image sensor 15 installed at the reading position C, and the reflected light is The light is converged by a lens on the contact image sensor 15, irradiated on a sensor element on the contact image sensor 15, and photoelectrically converted.

A white roller 17 is provided at an opposite portion of the contact image sensor 15 across the original, and is used as a white member for shading correction when reading by the contact image sensor 15.

Between the transport roller pair 13 and the paper discharge roller pair 14, an endor unit 18 and an endor platen 1
9 are installed. The endorser unit 18 is composed of a printing unit composed of alphabetic letters and numerals in which ink is impregnated, and a pressure solenoid (not shown) for pressing the printing unit toward the endorser platen 19.

The original is stopped on the endor unit 18 and fixed in a pressing direction by an endor platen 19, and alphabet characters and numerals are printed on the original surface by pressing the printing portion of the endor unit 18. be able to.

The contact image sensor 15 includes a document tray 8, a transport drum 11 and a transport roller 12, and a discharge tray 32.
Are arranged inside a U-shaped conveyance path. Further, the close contact image sensor 15 is disposed at a substantially straight portion of a transport path that is guided from the transport drum 11 and the transport rollers 12 to the discharge tray 32. In FIG. 1, reference numeral 20 denotes an SBU, 21 denotes an SCU, and 23 denotes an RCU.

FIG. 2 is an overall block diagram of a color image reading apparatus showing an embodiment of the present invention. C on SBU20
The reflected light of the document entering the CD 6 is converted into an analog signal having a voltage value according to the light intensity in the CCD 6. The analog signal is gain-adjusted to a predetermined amplitude by an analog processing circuit (not shown) on the SBU 20 and then input to an A / D converter to be converted into a digital signal. The digitized image signal is sent to NIPU 33 on SCU 21.
After performing shading correction, gamma correction, MTF correction, and the like, the image is binarized and output as a video signal together with a page synchronization signal, a line synchronization signal, and an image clock.

The video signal output from the NIPU 33 is output to the option IPU 26 via the connector 34. The video signal output to the option IPU 26 is subjected to predetermined image processing in the option IPU 26, and is input to the SCU 21 again.

The video signal input to the SCU 21 again is input to a selector (not shown). The other input of the selector is a video signal output from the NIPU 33, and has a configuration in which the option IPU 26 can select whether or not to perform image processing.

The video signal output from the selector is transmitted to the SiBC 35 for managing the image data storage means (DRAM).
And is stored in an image memory 40 composed of a DRAM. The image data stored in the image memory 40 is
The data is sent to the SCSI controller 36 and transferred to an external device such as a personal computer.

The analog image signal photoelectrically converted by the contact image sensor 15 is digitally converted on the RSBU 16. The digitized image signal is sent to the RCU 23 after being subjected to shading correction on the RSBU 16. The RCU 23 includes an image memory configured by a DRAM and a SiBC 35 that controls the image data memory.
After temporarily storing the image data in the image memory, the SCU2
Transfer to 1.

The image data sent from the RCU 23 to the SCU 21 and the image data output from the SiBC 35 on the SCU 21 are switchable, and any one of the image data is selected and transferred to the SCSI controller 36. CPU 37, ROM 38, RA
M39 is mounted, and the CPU 37 controls the SCSI controller 36 to communicate with an external device such as a personal computer. The CPU 37 also controls the timing of the traveling body motor 7, which is a stepping motor, the sheet feeding motor, and the transport motor. The ADU 30 has a function of relaying power supply of electrical components used in the ADF unit.

An input port connected to the CPU 37 on the SCU 21 is connected to the main body operation panel 2 via the IOB 24.
8 is connected. On the main body operation panel 28, a start switch (not shown) and an abort switch (not shown) are mounted. When each switch is pressed, the CPU 37 detects that the switch has been turned on via the input port.

FIG. 3 is an image data flow diagram showing an embodiment of the present invention. On the SBU 20, a CCD 6 composed of four lines of sensor lines of red (R), blue (B), green (G), and black and white (W), analog ASICs 52, 53,
54, A / D converters 55, 56 and 57 are mounted. Each color image data output from the CCD 6 is subjected to signal amplification and gain correction by analog ASICs 52, 53, and 54 that perform analog processing, and is digitized by A / D converters 55, 56, and 57.

Although the CCD 6 composed of four lines is used, switching means for selecting one of the two analog signals before signal amplification and gain correction (CC in this figure)
Although the switch 71 (see FIG. 4) as switching means is provided inside the D6, the switching means may be provided outside the CCD 6].
The configuration after C can be configured with three lines (since there is no case where signals of four lines are used at the same time).

The image data output from the SBU 20 is
It is input to the NIPU 33 which is an image processing ASIC on the SCU 21. The input image data is, if necessary, synchronized with the traveling body motor 7 or the motor clock for the original conveying motor (not shown), and the color image processing units 58, 59,
Line thinning is performed in 60, and thereafter, various image processing is performed.

Each color image data subjected to the image processing is stored in a line interpolation memory 62 through a line interpolation unit 61, and data of an address in the memory corresponding to the same read line is read out in order to correct a distance between CCD sensors. Is output. At this time, it is configured to select whether to output 24 bits for each color at the same time or to sequentially output 8 bits for each color in line units, and then output.

When image data is output to an external device by SCSI, an 8-bit line sequential output is sent to the SiBC 35 and output to the external device via the SCSI controller 36.

The image data is transferred to the network controller 2
7 (see FIG. 2) is output via the extended I / F. At this time, in accordance with the input I / F specification of the network controller 27, the simultaneous output of each color of 24 bits or the sequential output of 8 bit lines is selected according to a selection signal (not shown) from the network controller 27.

FIG. 4 is an internal structure diagram of a CCD showing an embodiment of the present invention. The inside of the CCD 6 is composed of a sensor line of four lines of red (R), blue (B), green (G), and black and white (W). Each sensor row includes a photoelectric conversion sensor unit for each color (black and white sensor, green sensor, red sensor, blue sensor) 63,
65, 67, 69, CCD analog shift register sections 64, 66, 6 for storing photoelectrically converted charges and sequentially outputting the charges.
8,70.

CCD analog shift register sections 64, 6
Analog data output from 6, 68, 70 is amplified by output amplifiers 72, 73, 74 and sent out of the CCD. At this time, the green (G) output and the monochrome (W) output are switched by the switch 71 according to the state of the GW selection signal.

Each color photoelectric conversion sensor section 63, 65, 67,
In 69, the relationship between the amount of incident exposure and the output voltage is quantitatively managed as sensitivity (unit: V / (1x · S)]. As the sensitivity is higher, a predetermined output voltage can be obtained with a small exposure amount or a short accumulation time (line cycle), and the signal amplification amount can be reduced in the analog ASIC, so that a high S / N can be obtained.

Each sensor row is provided with a filter so that an output can be obtained only for light of a specific color. That is, red (R), blue (B), and green (G) sensor rows are provided with filters of respective colors. Further, no filter is attached to the monochrome (W) line. Since the amount of light incident on the sensor itself is reduced by the presence of the filter, the sensitivity of the line with the filter is smaller than the sensitivity of the line without the filter. Also,
The sensitivity of green (G) is higher than that of red (R) and blue (B) from the transmittance of the filter and the like.

When amplifying a signal in the analog ASIC, the amplification width has a certain range so as to maintain a predetermined amplification accuracy. Therefore, it is possible to amplify with higher accuracy when a signal having a narrow voltage range is input than when a signal having a wide voltage range is input to a certain analog input signal of the analog ASIC. Accordingly, the monochrome line with high sensitivity and the line shared by the switch 71 are green (G) with the highest sensitivity among RGB.

FIG. 5 is a flowchart at the time of a reading operation in the color image reading apparatus according to the embodiment of the present invention. The operator sets reading conditions such as color / black and white, reading size, and resolution on a dialog box screen of driver software on an external device such as a personal computer connected to the reading device (S1).

The operator instructs the start of reading by the reading start button on the dialog box screen under the set reading conditions (S2).

When the start of reading is instructed by the operator, the driver software instructs the reading condition and the reading start to the CPU 37 in the reading device through an interface such as SCSI (S3).

The reading condition and the CPU 37 instructed to start reading read the color / black and white reading condition data under the reading condition,
The W selection signal is set to low level to select the G line (S
4, S5). Similarly, in the case of monochrome reading, the GW selection signal is set to the high level and the W line is selected (S
6).

When the CCD line selection is completed, the CPU 3
7 performs a series of reading operations and sends image data to an external device via an interface such as SCSI (S
7).

As described above, a monochrome line with high sensitivity is selected during monochrome reading, so that the line cycle can be set short enough to ensure the same S / N as in color reading. That is, it is possible to perform black-and-white reading at the same S / N as in color reading, and at a higher speed than in color reading. The CCD 6 of the color image reading apparatus according to the present embodiment is composed of four R, G, and B sensor lines with a color filter and four sensor lines of a W line without a color filter. W line sensor 6
There is a switch 71 for switching between the G line sensor 65 and the G line sensor 65 so as to switch to the W line sensor 63 in the monochrome reading mode and to the G line sensor 65 in the color reading mode. Has become. With such a configuration, black-and-white reading can be speeded up with the minimum light source luminance required for color reading without lowering the S / N.

[0049]

According to the first aspect of the present invention, black-and-white reading is performed using a line sensor having no color filter, and S / S is performed with the minimum light source luminance required for color reading.
It is possible to speed up monochrome reading without lowering N.

According to the second aspect of the present invention, one of the analog output of the line sensor without the color filter and the analog output of the color line sensor is selectively output, thereby achieving the output.
Since the apparatus is composed of three sets of analog processing units and digital conversion units for the output of the line sensor, the number of components can be reduced, and the size and cost of the apparatus can be reduced.

According to the third aspect of the present invention, since the sensitivity between the line sensors to be switched is set to a close value, the analog processing section can be configured with the same circuit (there is no need to add an amplification rate switching mechanism or the like). In addition, the component configuration is simplified, and the size and cost of the device can be reduced.

According to the fourth aspect of the present invention, the line sensor selection control is automatically performed according to a request from an external device, so that a special operation by the operator is not required, and the usability can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a color image reading apparatus according to an embodiment of the present invention.

FIG. 2 is an overall block diagram of a color image reading apparatus according to the embodiment of the present invention.

FIG. 3 is an image data flow diagram showing the embodiment of the present invention.

FIG. 4 is an internal structure diagram of a CCD showing an embodiment of the present invention.

FIG. 5 is a flowchart at the time of a reading operation in the color image reading apparatus according to the embodiment of the present invention;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 platen glass 2 first mirror 3 illumination lamp 4 second mirror 5 third mirror 6 CCD 7 traveling motor 8 document tray 9 pickup roller 10 registration roller pair 11 transport drum 12 transport roller 13 transport roller pair 14 discharge roller pair 15 Close contact image sensor 18 Endorser unit 19 Endorser platen 32 Discharge tray 63 Monochrome sensor 65 Green sensor 67 Red sensor 69 Blue sensor 64, 66, 68, 70 CCD analog shift register unit 71 Changeover switch 72, 73, 74 Output amplifier

Claims (4)

[Claims] 1. A three-line color line sensor provided with three color filters of red, green, and blue, an analog processing unit for processing an analog output of the color line sensor, and an analog output from the analog processing unit. In a color image reading apparatus having an A / D converter for converting data into digital data, a color sensor without a color filter is provided in addition to a color line sensor. A color image reading device comprising: 2. The method according to claim 1, wherein an analog output of the line sensor without a color filter and one of the analog outputs of the color line sensor are input.
A color image reading apparatus comprising: a switching unit for selectively outputting one of the lines; and a selection signal for determining which line is to be selected. 3. The color line of claim 2, wherein the analog output of the color line sensor input to the switching means has a value whose sensitivity is closest to the line of the line sensor without color filter among the lines of the color line sensor. A color image reading device, which is an analog output of a sensor. 4. The apparatus according to claim 2, wherein a color / color image is output from an external device connected via an interface.
It is possible to set a condition of which of black and white reading is to be performed, and has a control means for switching the selection signal in accordance with the setting of the color / black and white reading condition. A color image reading apparatus which controls the state of a selection signal as described above and controls the state of a selection signal so as to select a line without a color filter when monochrome reading is set.