JPH09261425A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively and stably obtain n-times resolutions as many as the number of valid picture elements in a light receiving element line. SOLUTION: This reader is provided with a light emitting device 1 with which an original is irradiated, light receiving element line 2 for receiving reflected light from the original, a photocoupler 21 for reflecting the light reflected on the original and converging it to the light receiving element line 2, a 1st driving means C1 for moving the light emitting device 1 in sub-scanning direction, a 2nd driving means for moving the light receiving element line 2 in the main scanning direction, image storage means for storing image data provided from the respective picture elements in the light receiving element line 2, and an image processing means for performing image processing with the image data stored in the image storage means. Each time the light receiving element 1ine 2 is moved in the main scanning direction for the unit of 1/n picture elements, the original is read, the image data are possessed (n) times for each picture element, and these image data are synthesized by the image processing means.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a digital copying machine,
The present invention relates to an image reading apparatus that reads an original by a digital method such as an image scanner and a facsimile, and stores and processes image data of the read original, and particularly to an image reading apparatus that can realize a high resolution image.

[0002]

2. Description of the Related Art In an image reading apparatus such as a digital copying machine, an apparatus having a high resolution is desired for reading an original having a fine image. In this case, in order to increase the resolution, a light receiving element (CCD) having a large number of effective pixels may simply be used.

[0003]

However, a CCD having a very large number of effective pixels is expensive as compared with a CCD having a small number of effective pixels, resulting in a high cost. Further, stable driving at high speed is more difficult than that having a small number of effective pixels, and the development of a high resolution CCD capable of stable high speed driving is currently in an insufficient state.

Therefore, an object of the present invention is to provide an image reading device which can stably obtain an image having a higher resolution at a low cost by using a CCD having the number of pixels currently used in a copying machine. There is.

[0005]

According to a first aspect of the present invention, there is provided a light emitting device for irradiating an original, a light receiving element array for receiving reflected light from the original, and an image reading device for reading the original. An optical coupler for reflecting the reflected light and condensing it on the light receiving element array, a first driving means for moving the light emitting device in the sub scanning direction with respect to the document, and the light receiving element array orthogonal to the sub scanning direction. Second driving means for moving in the main scanning direction, image storage means for storing image data obtained from each pixel of the light receiving element array, and image processing means for performing image processing by the image data stored in the image storage means. The document is read every time the light-receiving element array is moved in the main scanning direction in units of 1 / n pixel, and image data is acquired n times for one pixel of the light-receiving element. Synthesis by processing means Characterized in that to obtain n times the resolution by sense.

According to a second aspect of the present invention, there is provided a third driving means for moving the optical coupler in the sub-scanning direction with respect to the original, and by moving the optical coupler, at the position of the light receiving element array, The width of the reflected light from the original is condensed to n times the effective pixel width of the light receiving element array, and the original is read every time the light receiving element array is moved in the main scanning direction in units of the effective pixel width. It is characterized in that n-fold resolution is obtained by acquiring image data and performing a combining process by the image processing means.

A third aspect of the present invention is characterized in that even number of times of the n times of image data acquisition is performed during the backward scanning of the light emitting device.

According to the fourth aspect of the invention, the image data acquired at the even number of times is processed by the image processing means by reversing the image acquisition order.

A fifth aspect of the present invention is characterized in that n times the resolution and the resolution according to the light receiving element array are controlled so that they can be selected.

According to the sixth aspect of the present invention, the second driving means for moving the light receiving element array can set a plurality of units for moving the light receiving element array, and any one of the above can be set according to the selected resolution magnification. It is characterized in that the light receiving element array is moved in units of movement.

A seventh aspect of the present invention is characterized in that either one of the two image acquisition procedures is executed in accordance with the selected resolution magnification.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. An example in which the image reading device of the present invention is applied to a scanner unit of a color copying machine will be described. FIG.
FIG. 1A is a side view showing the configuration of the entire scanner unit, and FIG. 1B is a perspective view of the main part thereof. The scanner unit is equipped with an optical scanning system, irradiates the surface of the document 23 placed on the contact glass, and guides the reflected light from the document 23 to the one-dimensional image sensor (CCD) 2. In order to read the two-dimensional image of the document 23, the first carriage C1 and the second carriage C2 are reciprocally scanned in the sub-scanning direction indicated by the arrow in the figure. These first and second carriages C1,
The drive source of C2 is the stepping motor 5, which transmits its drive force to the first carriage C1 and the second carriage C2 via the scanner wire W.

The original 23 is exposed by the halogen lamp 1 which is a light emitting means. Then, the reflected light from the document 23 is refracted by the plurality of mirrors 4 of the optical scanning system, and the lens 2
3 which is the light receiving means on the CCD substrate 16 after being condensed by 1
An image is formed on the line CCD (image sensor) 2. The 3-line CCD 2 is controlled by various timing control signals generated by the gate array of the scanner control board 15,
The line information of the image components associated with each color of red, green, and blue is simultaneously captured. The components of each color are separated into even-numbered and odd-numbered pixels arranged in the line direction, and are output as serial image signals.

The structure of the control system of the scanner unit is shown in FIG. As shown in FIG. 2, the scanner unit is
It is composed of an IPU unit (image processing unit) 11, a main control unit 13, an operation display unit 14, and a scanner unit 24. The scanner unit 24 includes a scanner control board 15 and a CCD board 16.
And a scanner driver board 17. The scanner driver board 17 has three motor drivers 6, 8,
There are nine. The main control functions of the scanner unit 24 are motor control, analog automatic setting, digital signal processing setting, document detection processing, communication with the main body, projector compatibility, and the like.

The one-chip microcomputer (hereinafter, microcomputer 18) on the scanner control board 15 is the ROM 1
By executing a program stored in advance in 9 and reading / writing data or the like from / to the RAM 20, the entire scanner unit is controlled. Further, the microcomputer 18 is connected to the main controller 13 via a serial communication circuit, and performs an operation instructed by transmitting and receiving commands and data. Further, the main control unit 13 is connected to the operation display unit 14 via a serial communication circuit, and an instruction such as an operation mode can be set by a key input instruction from the user to the operation display unit 14.

The microcomputer 18 also includes the scanner motor 5,
The CCD micro step motor 7 and the lens micro step motor 22 are controlled. The microcomputer 18 realizes selection of an excitation pattern required for driving the motors 5, 7, and 22 and control of an excitation pattern switching timing by a macro service function using hardware incorporated therein.

The macro service function minimizes the frequency of occurrence of interrupts, which are mainly software processing, and suppresses the overhead of a series of processes of interrupt processing, register saving, register restoration, and return from the interrupt service routine. It is used to improve the service time of the CPU, and is a kind of DMA (Direct Memory Access) function.

Next, a specific method for artificially increasing the reading resolution in the main scanning direction will be described with reference to FIGS. This method is a method selected when the resolution increase rate is set high, but for simplicity, the method when the resolution increase rate is set to a lower 3 times (n = 3) will be described.

In the first scanning, the halogen lamp 1 moves in the sub-scanning forward direction, reflects the irradiation light on the original 23, and the reflected light is CC-reflected by the lens 21.
An image is formed on D2 (see scanning position A in FIG. 3). C
The image data incident on each pixel of the CD 2 is stored in the image data memory 10. After the end of the first scanning, the microstep motor 7 moves the CCD 2 by 1/3 pixel in the main scanning direction (see the second scanning position B in the figure).

The second scan is performed in the sub-scan return direction, and the image data acquired by each pixel of the CCD 2 is stored in the image data memory 10. After the second scanning is completed, the CCD 2 further moves by 1/3 pixel (see the third scanning position C).

The third scan is performed in the sub-scan forward direction, and the image data of each pixel is stored in the image data memory 10.
Is stored within. It should be noted that although the CCDs 2 are shown side by side in the main scanning direction in FIG. 3, this is for convenience of drawing and the CCD 2 is not actually moved in the main scanning direction.

Next, the image data stored in the image data memory 10 is subjected to image processing by the IPU 11. The image processing procedure at this time will be described below. In the figure, P is the original 2
3 shows an image state in one line with 3. CC
When D2 is at the initial position (first scanning position A), the image density value in the portion of the document 23 (hatched portion on one line P) corresponding to the area of the pixel number 1 and 2/3 of the pixel number 2 is It is assumed that the image density value is "9" and the image density value of the other part is "0". Here, the solid line dividing line of the CCD 2 shown is a dividing line showing an actual pixel unit, and the broken line shows a dividing line between pseudo pixels. The density value of the pseudo pixel surrounded by a circle is a value located at the center of each pixel.

The image data obtained in the first scan at the scanning position A is "9" for the pixel of pixel number 1. Further, in the pixel of the pixel number 2, the density of 2/3 thereof is 9 and the density of 1/3 thereof is 0. Therefore, this is averaged to obtain (9 × 2/3 + 0 × 1/3) density “6”. Become. Then, in the pixel of pixel number 3, density "0" is obtained.

The image data obtained in the second scanning at the scanning position B is mirror-image processed by the IPU 11 and inverted in the sub-scanning forward direction. Then, the pixel with the pixel number 1 is “9”, and the pixel with the pixel number 2 is “3” (9 ×
1/3 + 0 × 2/3), which is “0” in the pixel of pixel number 3.

The image data obtained in the third scanning at the scanning position C is "9" for the pixel of pixel number 1,
"0" (0x3 / 3) at pixel number 2 and pixel number 3
The pixel becomes “0”.

The following weighting calculation is performed on this image data to obtain the image data of each pseudo pixel. That is, in the pseudo pixel numbers 1 and 2, since the three pieces of image data are not aligned, the non-existing pseudo pixel data is added as 0 and divided by the number of existing pseudo pixels. Therefore, in pseudo pixel number 1, from (9 + 0 + 0) / 1
9 "is obtained. Further, in the pseudo pixel number 2, (9 + 9
Similarly, "9" is obtained from +0) / 2.

Next, the density values of the pseudo pixels marked with circles are weighted and added. Weighting is (density value) x (1
+ 1 / n). Here, n is the resolution magnification. However, only when the density values of the same pseudo pixel are the same,
No weighting is applied. Pseudo pixel number 3 is an example.
This is because weighting causes a large error. With such weighting, the pseudo pixel number 3 becomes (9 + 9 +
9) / 3 = 9, the pseudo pixel number 4 is (6 + 9 + 9 × 1.
3) /3=8.9, the pseudo pixel number 5 is (6 × 1.3 +
3 + 9) /3=6.6, the pseudo pixel number 6 is (6 + 3 ×
1.3 + 0) /3=3.3, the pseudo pixel number 7 is (0+
3 + 0 × 1.3) / 3 = 1, the pseudo pixel number 8 is (0 ×
1.3 + 0 + 0) / 3 = 0 and so on. In this embodiment, since the resolution magnification n is odd, the number of pseudo-pixels to be weighted is one, but in the case of an even number, the two central pseudo-pixels are weighted. If the resolution increasing rate is 2 times, the following resolution increasing method is used, so this method is not used.

Next, another specific method for increasing the reading resolution in the main scanning direction according to the present invention will be described with reference to FIG. This method is a method selected when the resolution increase rate is set low, and as an example, a method when the resolution increase rate is set to 3 times (n = 3) will be described.

First, the lens 21 is moved in the sub-scanning forward direction from the position shown in FIG. 4A by the microstep motor 22 to form an image of three times the effective pixel number of the CCD 2 shown in FIG. 4B. Stop at position. Next, the micro step motor 7 positions the CCD 2 at the first position A. In this state, the first scanning of the document 23 is performed. The first scan is performed by moving the first carriage C1 in the sub-scan forward direction, and the C at the first position A
The image data incident on the CD 2 is stored in the image data memory 10. At this time, the image data obtained by the CCD 2 is only 1/3 of the original 23 in the main scanning direction. First
After the end of the second scanning, the micro step motor 7 is CCD
2 is moved in the main scanning direction by the effective pixel and is installed at the second position B.

Next, the second scanning is performed in the sub-scan return direction, and the image data obtained as a result is stored in the image data memory 10. The image data obtained in this way is 1/3 of the image data that is adjacent to the acquired image data in the main scanning direction. After the second scanning is completed, the CCD 2 is further moved by the effective pixel in the main scanning direction.

Finally, the third scanning is performed in the sub-scanning forward direction, and the image data is stored in the image data memory 10 in the same manner.

Next, the image data memory 10 is subjected to the above procedure.
The image data stored in the image is processed by the IPU 11. That is, the image data sequentially obtained by the three scans are combined as shown in FIG. In the figure, A is the image data obtained in the first scan, and B is the second
The image data obtained by the third scan and C show the image data obtained by the third scan. In this case, since the second scan is performed in the sub-scan return direction, the IPU 11 first performs a mirror image process,
Flipped.

FIG. 6 shows the operation display unit 14 of the image reading apparatus.
It is shown. In this embodiment, the operation display unit 14 is normally in the normal mode for image quality, and C
The image reading is performed using the resolution corresponding to the number of effective pixels of the CD 2 as it is. When the user needs high image quality of high resolution, the mode is changed by pressing the high image quality mode key 12.

FIG. 7 shows an example of the display screen in the high image quality mode selected by the high image quality mode key 12. As shown in this figure, by pressing one of the resolution increase rate selection keys 25, the resolution increase rate can be selected.

[0035]

As described above, according to the image reading apparatus of the present invention, the light-receiving element array is moved in the main scanning direction by 1 / n pixel for each scanning to perform n times of scanning.
One pixel is pseudo-divided into n in the main scanning direction. As a result, the resolution in the main scanning direction is increased pseudo n times, and reading at a resolution n times the number of pixels of the installed light receiving element array can be obtained inexpensively and stably. is there.

According to the image reading apparatus of the second aspect, in addition to the effect of the first aspect, the optical coupler is moved in the sub-scanning direction, and the light receiving element array is moved in the main scanning direction by effective pixels for each scanning. By combining the image data obtained after the scanning is performed n times, it is possible to increase the resolution in the main scanning direction by n times and read the image. Since this method does not artificially increase the number of effective pixels of the light receiving element unlike the method of claim 1,
There is an effect that an image faithful to the original can be obtained without correcting the acquired image data.

In the image reading device of the third aspect, n
Since even number of times of image data acquisition is decided to be carried out at the time of scanning the light emitting device in the return direction, plural times of image reading is carried out at the time of reciprocation of the light emitting device, which enables image reading in a short time. Has the effect of becoming.

In the image reading apparatus according to the fourth aspect, the image data acquired at the even number of times is processed by the image processing means by reversing the image acquisition order, so the image data acquired at the odd number of times. The effect is that it can be consistent with.

In the image reading apparatus of the fifth aspect, n
Since the double resolution and the resolution according to the light-receiving element array are controlled to be selectable, the user can select one of the modes at the time of use. From this, when the user needs high resolution and does not need to perform processing in a short time, the high image quality mode is selected, and when the user does not need high resolution and needs to perform processing in a short time. Has the effect that it is possible to select the normal mode.

According to another aspect of the image reading apparatus of the present invention, the second driving means for moving the light receiving element array can set a plurality of units for moving the light receiving element array, and any one of the above can be selected according to the selected resolution magnification. Since the light receiving element array is moved in the unit of movement, the increase ratio of resolution can be selected, and the range of selection can be expanded according to the user's time and image quality needs.

According to the image reading apparatus of the seventh aspect, either the image acquisition procedure of the first aspect or the second aspect is executed according to the selected resolution magnification. Therefore, the increase magnification of the selected resolution is increased. There is an effect that it is possible to select a resolution increasing procedure suitable for the magnification depending on the level.

[Brief description of drawings]

FIG. 1 is a side view and a perspective view showing an overall configuration of an embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a block diagram showing an example of a control system of the image reading apparatus according to the present invention.

FIG. 3 is a conceptual diagram for explaining a first resolution increasing method.

FIG. 4 is a conceptual diagram for explaining a second resolution increasing method.

5 is a display example for explaining processing of image data read by the method of FIG.

FIG. 6 is a plan view showing an example of an operation display unit of the image reading apparatus.

FIG. 7 is a screen example of an operation display unit when a high image quality mode is selected.

[Explanation of symbols]

 1 Halogen Lamp 2 CCD 4 Mirror 5 Scanner Motor 6, 8, 9 Motor Driver 7 CCD Motor 10 Image Data Memory 11 IPU 12 High Quality Mode Key 13 Main Control Section 14 Operation Display Section 15 Scanner Control Board 16 CCD Board 17 Scanner Driver Board 18 one-chip microcomputer 19 ROM 20 RAM 21 lens 22 lens motor 23 original document 24 scanner section 25 selection key C1 first carriage C2 second carriage

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazushige Takuma 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Hiroshi Soga 1-3-3 Nakamagome, Ota-ku, Tokyo Stock company Ricoh

Claims (7)

[Claims] 1. A light emitting device for irradiating an original, a light receiving element array for receiving reflected light from the original, an optical coupler for reflecting the reflected light from the original and condensing on the light receiving element array, and the light emission. First driving means for moving the apparatus in the sub-scanning direction with respect to the document, second driving means for moving the light receiving element array in the main scanning direction orthogonal to the sub-scanning direction, and each pixel of the light receiving element array. An image storage unit for storing the obtained image data and an image processing unit for performing image processing with the image data stored in the image storage unit are provided, and each time the light receiving element array is moved in the main scanning direction in units of 1 / n pixel. The original is read, the image data is acquired n times for one pixel of the light receiving element, and the image processing means performs a combining process to obtain n times the resolution. apparatus. 2. A third drive means for moving the optical coupler in the sub-scanning direction with respect to the original, and by moving the optical coupler, the width of the reflected light from the original at the position of the light receiving element array. Is condensed to n times the effective pixel width of the light receiving element array, and the document is read every time the light receiving element array is moved in the effective pixel width unit in the main scanning direction to obtain n image data. N by combining with the image processing means
The image reading device according to claim 1, wherein the image reading device has a double resolution. 3. The image reading apparatus according to claim 1, wherein the even-numbered data acquisition of the n-time image data acquisition is performed at the time of scanning in the returning direction of the light-emitting device. 4. The image data acquired in the even number of times is
4. The image reading apparatus according to claim 3, wherein the image processing means reverses the order of image acquisition. 5. The n-fold resolution and the resolution according to the light-receiving element array are controlled to be selectable.
2, 3 or 4 image reading device. 6. The second drive means for moving the light-receiving element array can set a plurality of units for moving the light-receiving element array, and the light-receiving element array can be moved in any one of the above-mentioned movement units according to a selected resolution magnification. It moves, It is characterized by the above-mentioned.
2, 3, 4 or 5 image reading device. 7. The image reading apparatus according to claim 6, wherein one of the two image acquisition procedures is executed according to the selected resolution magnification.