JPH01129668A - Picture reader - Google Patents

Abstract

PURPOSE:To realize an excellent picture reader by varying the frequency characteristic of a picture signal in response to the kind of a read picture so as to attain the reading utilizing the characteristic of a read picture. CONSTITUTION:The picture signal subjected to dark clamping is amplified by amplifiers 100p, 100q and 100r whose frequency characteristic is variable. The frequency characteristic of the amplifier is set by using a signal from a timing control section 100a via a D/A converter 100y. A picture signal from the amplifiers 100p, 100q, 100r is subjected to analog/digital conversion by A/D converters 100s, 100t, 100u, and set to the latches 100v, 100w, 100x of the next stage. The latches 100v, 100w, 100x are outputted by a signal from the control section 100a as serial multi-level. Thus, the frequency characteristic of the picture signal from the image sensor is variable by the amplifiers 100p, 100q, 100r.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an image reading device having a reading means for reading an original image.

[Description of conventional technology]

Conventionally, an image reading device amplifies an image signal from an image sensor, performs analog/digital conversion on the image signal, and obtains read image information as a digital signal. According to this conventional method, the frequency characteristics of the image reading device are determined by the optical MTF determined by the lens and image sensor aperture shape, and the electrical frequency characteristics of the amplifier that amplifies the photoelectrically converted image signal from the image sensor. .

According to such conventional image reading apparatuses, the reading frequency characteristics are fixed, making it difficult to read images that take advantage of their characteristics.

[Purpose of the invention]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a high-quality image reading device by changing the frequency characteristics of an image signal depending on the type of image to be read in the image reading device.

〔Example〕

(Explanation of External Shape) FIG. 1 shows an external view of a digital color copying machine to which the present invention is applied.

The whole can be divided into two parts.

The upper part of Figure 1 shows the color image scanner section 1 (which reads the original image and outputs digital color image data).
The controller section 2 includes a scanner section 1 (hereinafter abbreviated as a scanner section 1), and a controller section 2, which is built into the scanner section 1 and performs various image processing of digital color image data, and has processing functions such as an interface with external devices.

The scanner section 1 reads a three-dimensional object placed downward under the document presser 11, a sheet document, and also has a built-in mechanism for reading a large-sized sheet document.

Further, the operation section 10 is connected to the controller section 2, and is used to input various information regarding the copying machine. The controller section 2 instructs the scanner section 1 and the printer section 3 regarding operations according to the input information. Further, when it is necessary to perform complicated editing processing, a digitizer or the like is attached in place of the document presser 11, and this is connected to the controller section 2, thereby making it possible to perform sophisticated processing.

The lower part of FIG. 1 is a printer section 3 for recording the color digital image signal output from the controller section 2 on recording paper. In this embodiment, the printer section 3 is a full color ink jet printer using an ink jet recording head described in Japanese Patent Laid-Open No. 54-59936.

The two parts described above can be separated, and can be installed at separate locations by extending the connecting cable.

(Printer Section) FIG. 2 is a sectional view from the side of the digital color copying machine shown in FIG. 1.

First, an exposure lamp 14, a lens 15, and an image sensor 16 that can read line images in full color.
(CCD in this embodiment), the original table glass 17.
Original T+l placed on 17! + 1 image, a projected image by a blank detector, or a sheet original image by the sheet feeding mechanism 12 is read. Next, various image processing is performed by the scanner section 1.
The controller section 2 performs this, and the printer section 3 records the information on recording paper.

In FIG. 2, recording paper is stored in two paper feed cassettes I-20 that store cut paper of small standard sizes (A4 to A3 in this example) and large size (A2 to A1 in this example).
The paper is supplied from a roll paper 29 for recording up to the same size.

In addition, by feeding recording sheets one by one through the manual feed port 22 shown in FIG. 1 along the paper feed section cover 21, it is also possible to feed the recording sheets manually from outside the apparatus.

The pick-up roller 24 is a roller for feeding cut sheets one by one from the paper feed cassette 20, and the fed cut sheets are conveyed to the 10th feed roller 26 by the cut paper feed roller 25. be done.

The roll paper 29 is sent out by a roll paper feed roller 30, cut into a standard length by a cutter 31, and then transferred to the paper feed number 10.
- It is conveyed to La 26.

Similarly, the recording paper inserted through the manual feed slot 22 is conveyed to the paper stack error roller 26 by the manual feed roller 32.

Pick up roller 24, cut paper feed roller 25
, the roll paper feed roller 30, the 10th paper feed roller 26, and the manual feed roller 32 are connected to a paper feed motor (not shown in the drawings, D
It is driven by a C servo motor (using a C servo motor), and can be turned on and off at any time by electromagnetic clutches attached to each roller.

When the printing operation is started in accordance with an instruction from the controller section 2, recording paper selectively fed from one of the above-mentioned paper feeding paths is conveyed to the paper feeding path 26. In order to eliminate the skew of the recording paper, after creating a predetermined amount of paper loops, the 10th paper feeder 26 is turned on and the recording paper is conveyed to the 20th paper feeder 27.

Between the 10th paper feed roller 26 and the 20th paper feed roller 27, a predetermined amount of paper is applied to the recording paper in order to perform an accurate paper feeding operation between the paper feed roller 28 and the 20th paper feed roller 27. Create a buffer. The buffer amount detection sensor 33 is a sensor for detecting the buffer amount. By creating a buffer in the middle of paper transport, it is possible to reduce the load on the paper feed roller 28 and paper feed roller 27, especially when transporting large-sized recording paper, allowing accurate paper feeding operation. become.

When printing with the recording head 37, the recording head 3
A scanning carriage 34 consisting of 7 etc. is a carriage.
The rail 36 is scanned back and forth by the scanning motor 35. In the forward scan, an image is printed on the recording paper, and in the backward scan, the paper feed roller 28 performs an operation to feed the recording paper by a predetermined amount. At this time, while the drive system is detected by the buffer amount detection sensor 33 using the paper feed motor, control is performed so that the buffer amount is always a predetermined amount.

The printed recording paper is discharged to the paper discharge tray 23, and the printing operation is completed.

Next, a detailed explanation of the scanning carriage 3 and the invention will be given using FIG.

In FIG. 3, a paper feed motor 40 is a drive source for intermittently feeding recording paper, and a paper feed motor 40 is a driving source for intermittently feeding the recording paper.
The 20th paper feeder 27 is driven via the 0-ra clutch 43.

The scanning motor 35 moves the scanning carriage 34 to the scanning belt 34.
This is a driving source for moving the robot in the directions of arrows A and H. In this embodiment, since accurate paper feeding control is required, pulse motors are used for the paper feeding motor 40 and the scanning motor 35.

When the recording paper reaches paper feed number 20-27, paper feed number 20
- The clutch 43 and paper feed motor 40 are turned off, and the recording paper is conveyed over the platen 39 to the paper feed roller 28.

The recording paper is detected by a paper detection sensor 44 provided on the platen, and sensor information is used for position control, jam control, etc.

When the recording paper reaches the paper feed roller 28, the paper feed number 20-
The clutch 43 and the paper feed motor 40 are turned off, and a suction operation (not shown) is performed from inside the platen 39 to bring the recording paper into close contact with the platen 39.

Prior to the image recording operation on recording paper, the scanning carriage 34 is moved to the position of the home position sensor 41,
Next, forward scanning is performed in the direction of arrow A, and cyan, magenta, yellow, and black inks are ejected from the recording head 37 onto the recording paper from predetermined positions to record an image. After recording the image for a predetermined length, the scanning carriage 34 is stopped, and conversely, backward scanning is started in the direction of arrow B, and the scanning carriage 34 is returned to the position of the home position sensor 41. During the backward scan, the paper is fed by the length recorded by the recording head 37 in the direction of arrow C by driving the paper feed roller 28 by the paper feed motor 40.

In this embodiment, the recording head 37 is an ink jet type ink jet nozzle that ejects ink droplets using heat as described above, and uses four of 256 nozzles each assembled into one.

Scanning carriage 34 is home position sensor 41
When it stops at the home position detected by , the recording head 37 performs a recovery operation. This is a process for stable printing operation, and in order to prevent unevenness at the start of ejection caused by changes in the viscosity of the ink remaining in the nozzles of the print head 37, paper feeding time, internal temperature of the device, etc. This is a process in which pressure is applied to the recording head 37, ink is idly ejected, etc. according to preprogrammed conditions such as ejection time and the like.

By repeating the operations described above, an image is recorded on the entire surface of the recording paper.

(Scanner Section) Next, the operation of the scanner section 1 will be explained using FIGS. 4 and 5.

FIG. 4 is a diagram for explaining the mechanical mechanism inside the scanner section 1. As shown in FIG.

The COD unit 18 is a unit composed of a CCD 16, a lens 15, etc., and includes a main scanning motor 50 fixed on a rail 54, a pulley 51, a pulley 52, and a wire 53.
It moves on the rail 54 by a drive system in the main scanning direction consisting of the following, and reads the image on the document platen glass 17 in the main scanning direction. The light shielding plate 55 and home position sensor 56 are used for position control when moving the CCD unit 1-18 to the main scanning home position in the correction area 68 in the figure.

The rail 54 rests on rails 65 and 69, and includes a sub-scanning motor 60, pulleys 67, 68, 71, and 76, and a shaft 72.
73, is moved by a drive system in the sub-scanning direction consisting of wires 66 and 70. Light shielding plate 57, home position
The sensors 58 and 59 are used to control the home scan mode for each sub-scan in a book mode for reading a document such as a book placed on the document table crow 17, and in a sheet mode for reading a sheet.
It is used for position control when moving the rail 54 to a certain position.

Sheet feed motor 61, sheet feed rollers 74 and 75,
The pulleys 62 and 64 and the wire 63 are mechanisms for feeding the sheet original. This mechanism is located on the document table glass 17, and transports the sheet document placed face down to the sheet feed roller 7.
This is a mechanism for feeding a predetermined amount at a time of 4.75.

FIG. 5 is an explanatory diagram of the reading operation in book mode and sheet mode.

In the book mode, the CCD unit 18 is moved to the book mode home position (book mode IP) shown in the correction area 68 in FIG. Start reading the entire document.

Prior to scanning the original, processing such as shading correction, black level correction, and color correction is performed in the correction area 68. Thereafter, scanning in the main scanning direction is started by the main scanning motor 50 in the direction of the illustrated arrow. When the reading operation of the area indicated by (2) is completed, the main scanning motor 50 is reversed, and the sub-scanning motor 60 is driven to move the area (2) to the correction area 68 in the sub-scanning direction. Subsequently, similarly to the main scanning of the area (2), processing such as shading correction, black level correction, color correction, etc. is performed as necessary, and the reading operation of the area (2) is performed.

By repeating the above scanning, the entire areas ① to ② are read, and after completing the reading operation in the area ②, the CCD unit 18 is returned to the hook mode home position again.

In this embodiment, the document platen glass 17 can read a maximum A2 size document, so in reality it must be scanned more times, but in this explanation, the operation is simplified to make it easier to understand. .

In the seat mode, the CCD unit 18 is moved to the seat mode home position (seat mode H) shown in the figure.
P), and by moving the sheet original in the area (3) while operating the sheet feed motor 61 intermittently, the sheet original is repeatedly read and the entire sheet original is read.

Prior to scanning the document, processing such as shading correction, black level correction, and color correction is performed in the correction area 68, and then scanning in the main scanning direction is started by the main scanning motor 50 in the direction of the arrow shown in the figure. When the forward scanning operation of the area (2) is completed, the main scanning motor 50 is reversed, and during this backward scanning, the sheet feed motor 61 is driven to move the sheet original by a predetermined amount in the sub-scanning direction. Subsequently, the same operation is repeated to read the entire sheet document.

Second, assuming that the reading operation described above is a reading operation at the same magnification, the area that can be read by the CCD unit 18 is actually a wide area as shown in FIG. This is because the digital color copying machine of this embodiment has a built-in magnification/reduction function. That is, as explained above, since the area that can be recorded by the recording head 37 is fixed at 256 bits at a time, for example, when performing a 50% reduction operation, the image information of an area of at least double 512 bits is This is because it is necessary. Therefore, the scanner section 1 has a built-in function of reading and outputting image information of an arbitrary image area by one main scanning reading.

(Film Projection System) The scanner section 1 of this embodiment can be equipped with a projection exposure means for film projection.

FIG. 6 is a perspective view of the scanner unit 1 with a projector unit 81 serving as projection exposure means and a reflecting mirror 80 attached.

The projector unit 81 is a projector for projecting negative film and positive film, and the film is held in a film holder 82 and attached to the projector unit 81. Projector unit 81
The image projected from is reflected by the reflection mirror 80,
Fresnel lens 83 is reached. fresnel lens 83
converts this image into parallel light and forms the image on the document table glass 17.

In this way, negative film and positive film images are formed on the document table glass 17 by the projector unit 81, the reflective mirror 80, and the Fresnel lens 83.
image reading becomes possible.

FIG. 7 is a diagram for explaining the film projection system in more detail.

The projector unit 81 includes a halogen lamp 90
, reflection plate 89, condensing lens 91, film holder 8
2. Consists of a projection lens 92.

The direct light emitted by the halogen lamp 90 and the light reflected by the reflection plate 89 are condensed by a condenser lens 91 and reach the window of the film holder 82 . The film boulder 82 has a window slightly larger than one frame of negative film or positive film, so that film can be loaded inside with plenty of room.

The projection light reaching the window of the film holder 82 passes through the film mounted therein, thereby obtaining a projected image of the film. The projected image thus obtained is optically magnified by the projection lens 92, changed in direction by the reflecting mirror 80, and then converted into a parallel light image by the Fresnel lens 83.

The CCD unit 18 inside the scanner 1 reads this image in the book mode described above and converts it into a video signal.

FIG. 8 is a diagram showing an example of the relationship between the film and the projected image formed on the document table glass.

22 x 34. The film image of mm is shown magnified eight times and focused on the original platen glass 17.

(Overall Functional Block Description) Next, the functional blocks of the digital color copying machine of this embodiment will be described using FIG. 9.

The control units 102, 111, and 121 are control circuits that control the scanner unit 1, controller unit 2, and printer unit 3, respectively, and include a microcomputer, a program RO
It consists of M, data memory, communication circuit, etc. The control units 102 to 111 and the control units 111 to 121 are connected by a communication line, and a so-called master-slave control mode is adopted in which the control units 102 and 121 operate according to instructions from the control unit 11. ing.

When operating as a color copying machine, the control section 111 operates according to input instructions from the operation section 10 and the digitizer 114.

As shown in FIG. 6, the operation section 10 uses, for example, a liquid crystal (T, CD display section 84) as a display section, and is equipped with a touch panel 85 made of transparent electrodes on its surface. Selection instructions such as color specifications and editing operation specifications can be made. In addition, keys related to operations, such as a key start key 87 for instructing to start copying, a key-stop key 88 for instructing to stop copying, a key reset key 89 for returning the operation mode to the standard state, and a key reset key 89 for projector selection. Key to do - Projector key 86
Frequently used keys such as keys are provided independently.

The digitizer 114 is used to input position information for trimming, masking, etc., and is connected as an option when complex editing processing is required.

The control unit 111 also controls a control circuit-I/F control unit 112 of a general-purpose parallel interface such as IEEE-488, so-called GP-IB interface, and outputs image data between external devices. , remote control by external devices can be performed via this interface.

Furthermore, the control unit 111 includes a multi-value synthesis unit 106 that performs various types of processing on images, an image processing unit], a binarization processing unit 108, a 2x synthesis unit 109, and a buffer memory 110.
It also controls the

The control unit 102 controls a mechanical drive unit 105 that controls the drive of the mechanism of the scanner unit 1 described above, an exposure control unit 103 that controls the exposure of a lamp when reading a reflective original, and a halogen lamp when using a projector. The exposure controller 104 controls the exposure control section 90. In addition, the control unit 1
02 also controls the analog signal processing unit 1OO1 input image processing unit 101 that performs various processes related to images.

The control unit 121 includes a mechanical drive unit 105 that controls the drive of the mechanism of the printer unit 3 described above, and a mechanism that absorbs time variations in the mechanical operation of the printer unit 3 and compensates for delays due to the mechanical arrangement of the recording heads 117 to 120. Synchronous delay memory 1]
5.

Next, the image processing block in FIG. 9 will be explained along the flow of the image.

The image formed on the CCD], 6 is converted into an analog electrical signal by the CCD 16. The converted image information is serially processed in the order of red → green → blue and input to the analog signal processing unit 100. Analog signal processing section 1
In 00, sample and hold for each color of red, green, and blue.
After correcting the dark level, controlling the dynamic range, etc., the signal is subjected to analog-to-digital conversion (A/D conversion) and converted into a serial multivalued (in this example, 8 bits long for each color) digital image signal. It is output to the input image processing unit 101.

FIG. 11 is a diagram for explaining the analog signal processing section 100 in detail.

In FIG. 11, an image of a 10 oz original is formed on a CCD 16 by a lens 15. The CCD 16 photoelectrically converts this formed image into a serial analog electric signal such as red → green → blue. This electrical signal is transmitted to the amplifier 100b.
After being amplified by the image signal, the signal is input to a low-pass filter 100C which removes noise components from the image signal. This image signal is converted to S by a signal from the timing control section 100a.
/I-I circuit 100d, ]-00e.

The signal is separated into red (R), green (G), and blue (B) color image signals at 100f.

The variable amplifiers 100g, 100h, and 100i are voltage-controlled amplifiers, and are controlled by the output voltage of the D/A converter 100g. The image signals separated into each color are sent to the D/A converter 1 by a signal from the timing control section 100a.
variable amplifier 100g, 100h, ]00i via 00y
The signal is amplified to have an open amplitude when reading a white board.

Capacitors 100j, 100, 1001 and switch 100m.

100n and 100o perform dark clamping of the image signal using a signal from the timing control section 100a. Similarly to the above, the dark clamp level can be set via the D/A converter tooy using a signal from the timing control section.

The dark-clamped image signal is amplified by amplifiers 100p, 100q, and 100r whose frequency characteristics can be varied. - As an example, FIG. 12 shows a block diagram in which 100p, 100q, and 100r amplifiers are configured with low-pass active filters. In the low-pass active filter shown in FIG. 12, the resistance value of the variable-Q resistance element RQ changes depending on the voltage from the D/A converter 100y, thereby changing the frequency characteristics of the low-pass filter. 13th
The figure shows amplifier L when Q is variable from 0.2 to 1.6.
The frequency characteristics of 00p, 100q, and 100r are shown. The frequency characteristics of this amplifier can be set via the D/A converter 100y using a signal from the timing control section 100a. Amplifiers 100p, 100q.

The image signal from 100r is converted to A/D converter 100s.
.

Loot, 100u performs analog/digital conversion, and the next stage is set to latches 100v, 100w, and 100x.

Latch 100v, 100w, 1. OOx is output to the input processing unit 101 as a serial multi-value (8 bits for each color) according to a signal from the timing control unit 100a.

From the above, the frequency characteristics of the image signal from the image sensor can be varied by the amplifiers L00p, 100q, and 100r.

That is, depending on the type of read image, the timing control section 1
D/A converter tooy by digital signal from 00a
, the frequency characteristics of amplifiers L00p, 100q, and 100r are changed. In the case of a smooth image with little density change, the frequency characteristics of the amplifiers 100p, 1ooq, and 100r are set to Q=0.2 in FIG. 13, and smoothing is applied to the image signal from the image sensor. It is possible to obtain smooth image signals. Furthermore, for image signals containing high spatial frequency components such as characters and thin lines, amplifiers 100p and 1ooq are used.

The frequency characteristics of 100r are set to Q=1.6 in FIG. 13, and edges are emphasized by lifting the high frequency components of the image signal from the image sensor.
An image signal with high contrast can be obtained. Furthermore, for images containing a mixture of text and pictures, the amplifier L0
The frequency characteristics of 0p, 100q, and 100r are expressed as Q in Figure 13.
= approximately 0.8, it is possible to read the image faithfully.

In this way, by changing the frequency characteristics of the amplifier depending on the type of image to be read, reading that takes advantage of the characteristics of the image is possible.

The type of read image is input from the operation unit 10. In another embodiment, a well-known automatic image type recognition technology is used to determine the image type and frequency characteristics in the first scan, and then perform the actual reading process in the next scan. You can configure it as you like.

The input image processing unit 101 similarly performs correction processing necessary in the reading system, such as shading correction, color correction, and γ correction, on the serial multivalued digital image signal.

The multi-value synthesis section 106 of the controller section 2 is connected to the scanner section 1.
This is a circuit block that performs selection and compositing processing between a serial multi-value digital image signal sent from a serial multi-value digital image signal and a serial multi-value digital image signal sent via a parallel I/F. The selectively combined image data is sent to the image processing unit 107 as a serial multi-level digital image signal.

The image processing unit 107 performs smoothing processing, edge enhancement,
This circuit performs heat extraction, masking processing for color correction of recording ink used in the recording heads 117 to 120, and the like. The serial multilevel digital image signal output is input to the binarization processing unit 108 and the buffer memory 110, respectively.

The binarization processing unit 108 is a circuit for binarizing a serial multilevel digital image signal, and can select simple binary processing using a fixed slice level, pseudo halftone processing using a dither method, etc. Here, the serial multi-value digital image signal is converted into a four-color binary parallel image signal.

Image data of four colors is sent to the binary synthesis unit 109, and image data of three colors is sent to the buffer memory 110.

The binary synthesis unit 109 selects the three-color binary parallel image signal sent from the buffer memory 1.10 and the four-color binary parallel image signal sent from the binarization processing unit 108. This is a circuit for synthesizing four-color binary parallel image signals.

The buffer memory 110 is a buffer memory for inputting and outputting multivalued images and binary images via a parallel I/F, and has memory for three colors.

The synchronization delay memory 115 of the printer section 3
Absorption of time variations in mechanical operation and recording head 117~
This is a circuit for correcting the delay due to the mechanical arrangement of the recording heads 117 to 120, and internally also generates the timing necessary for driving the recording heads 117 to 120.

The head driver 116 drives the recording heads 117 to 120.
This is an analog drive circuit for driving the recording heads 117 to 120, and internally generates signals that can directly drive the recording heads 117 to 120.

The recording heads 117 to 120 eject cyan, magenta, yellow, and black ink, respectively, to record an image on recording paper.

FIG. 10 is an explanatory diagram of the timing of images between the circuit blocks described in FIG. 9.

Signal BVE is a signal indicating the image effective section for each scan in the main scanning reading operation explained in FIG. Signal B
Full-screen image output is performed by outputting VE multiple times.

The signal VE is a signal indicating the valid section of the image read by the CCD 16 for each line. Only the signal VE is valid when the signal BVE is valid.

Signal VCK is a clock signal for sending out image data VD. Signal BVE and signal VE also change in synchronization with this signal VCK.

The signal H3 is a signal used when the valid and invalid sections are repeated discontinuously while the signal VE outputs one line.
If the signal VE is continuously valid while outputting one line, it is an unnecessary signal. This is a signal indicating the start of one line of image output.

As described above, according to this embodiment, for an image with little change in density, by adjusting the frequency characteristics of the amplifier to a low frequency, it is possible to smooth the image signal and obtain a smooth image signal. In addition, for images containing high spatial frequency components such as characters and thin lines, edges are emphasized by increasing the high frequency characteristics of the amplifier, making it possible to obtain a clear image signal with high contrast.

In this way, depending on the type of image to be read, it is possible to perform reading that takes advantage of the characteristics of the image.

Note that the present invention is not limited to the embodiments described above, and can be applied to various electrophotographic printers, thermal printers, black and white sensors, R, .
Of course, the present invention is also applicable to cases where separate sensors are used for G, B, and the like.

[Brief explanation of the drawing]

Fig. 1 is an external view of a digital color copying machine to which the present invention is applied, Fig. 2 is a sectional view from the side of the digital color copying machine of Fig. 1, and Fig. 3 is a detailed view of the scanning carriage 3 and the invention. 4 is a diagram for explaining the mechanical mechanism inside the scanner section I. FIG. 5 is an explanatory diagram of the reading operation in book mode and sheet mode. FIG. 6 is a diagram for explaining the projection exposure on the scanner section 1. FIG. 7 is a detailed explanatory diagram of the film projection system, and FIG. 8 shows the projected image formed on the film and document table glass. 9 is an explanatory diagram of functional blocks of a digital color copying machine to which the present invention is applied. FIG. 10 is a diagram illustrating image timing between the circuit blocks of FIG. 9. , FIG. 11 is a block diagram showing the configuration of an analog processing section according to an embodiment of the present invention, FIG. 12 is a block diagram of an amplifier with variable frequency characteristics, and FIG.
FIG. 3 is a frequency characteristic diagram when the Q of the amplifier shown in FIG. 12 is made variable.

Claims (1)

[Claims] a reading means for reading an original image and generating an image signal; a frequency characteristic control means for varying the frequency characteristics of the image signal of the reading means according to the characteristics of the original image;
An image reading device comprising processing means for processing an image signal whose frequency characteristics have been changed by the frequency characteristic control means.