JP2989446B2 - Image reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, such as a copying machine or a scanner, which irradiates a document with an illuminating device and reads reflected light or transmitted light thereof with a photoelectric conversion element.

[0002]

2. Description of the Related Art The applicant has previously disclosed in Japanese Patent Application No. 4-49652 that a perfect circle read by scanning the screen in the horizontal direction with an image sensor is not projected horizontally on a high-definition screen. For this reason, a configuration was proposed in which the pixel ratio of the image data supplied to the HDTV screen was changed.

[0003]

However, in the above-mentioned prior application, the read image is displayed as it is on a one-to-one basis, and is not accompanied by enlargement or reduction. When enlarging or reducing an image read in accordance with the length of the HDTV screen in the vertical or horizontal direction, changing the pixel ratio independently increases the processing time. become. Therefore, it is necessary to simultaneously perform enlargement or reduction and pixel ratio compensation.

[0004]

Accordingly, the present invention provides a method for reading
Optical scanning means for scanning the designated area in the main scanning direction
And a stepper for driving the optical scanning means in the sub-scanning direction
Stepping motor and stepping motor
Motor controller that supplies pulses and main scanning of image data
And enlargement or reduction in the direction
A monitor consisting of rectangular pixels that output images
In the image reading apparatus having the
When displaying an image on the monitor screen,
The magnification or reduction of the monitor in the main scanning direction
System that sets the value obtained by multiplying the pixel ratio by the pixel ratio compensation coefficient
The control unit is provided.

[0005]

According to the present invention, pixel ratio compensation is performed simultaneously in the process of scaling.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows a configuration of a flatbed scanner when reading a reflection original. In FIG. 1, 1 is a document to be read, 2 is a platen glass made of a transparent member on which the document 1 is placed, and 3 is a document 1 placed on the platen glass with respect to the platen glass 2 from above the document 1. An original pressing plate 4 to be pressed is a fluorescent lamp for irradiating the original 1 placed on the platen glass 2 with light, and 5 is a second light, which will be described later, reflects light emitted from the fluorescent lamp 4 and reflected by the original 1. A first mirror unit 9 configured by a photo sensor and the like; 10 a first mirror unit including a fluorescent lamp 4 and a first mirror 5;
Reference numeral 6 denotes a second mirror that reflects the reflected light guided by the first mirror 5 toward a third mirror described below, and reference numeral 7 reflects the reflected light guided by the second mirror toward a lens described below. A third mirror 11 is a second mirror unit composed of a second mirror 6 and a third mirror 7, and 8 is a device that couples the reflected light guided by the third mirror onto a CCD line sensor 9. It is a lens that images. In this embodiment, the lens 8 forms reflected light having a length equivalent to 1 mm on the platen glass 2 into 24 pixels of the CCD sensor 9.

The first mirror unit 10 and the second mirror unit 11 functioning as optical scanning means are 2: 1 by a stepping motor (not shown) and a driving mechanism (not shown) for transmitting the power of the stepping motor. It moves in the arrow direction A (sub-scanning direction) at the scanning speed of. When the original to be read is a transparent original such as a film or an overhead projector sheet, for example, as shown in FIG. 1, it is located above the original 1 and is integrated with the first mirror unit 10 so as to move in the direction A. Then, light can be applied to the original 1 from above, and the transmitted light can be guided to the CCD 9 as in the case of the reflective original.

FIG. 2 is a block diagram showing the present embodiment.
The reading unit 12 reads a document placed on the platen glass as an analog electric signal using the CCD line sensor as described above, converts the signal into digital data using an analog / digital converter (not shown), and corrects uneven illumination and the like. After that, the image data is supplied to the main scanning area control unit 13.

Prior to reading a document, the main control unit 19
Receives code data 18 such as commands and parameters necessary for determining reading conditions from the host device via the interface 16. The types of commands in the received data and the reply data in this embodiment are as shown in FIG. In FIG. 10, R1 in the received data is a normal read command for outputting the read image in a one-to-one relationship, and R2 is used to scale the read image in at least the vertical or horizontal direction of the high-definition screen. This is the HDTV read command to be output. A horizontal reference command K1, a vertical reference command K2, or a horizontal / vertical independent command K3 is set corresponding to the HDTV read command R2. Further, a command P1 indicating that the output is a high-definition monitor or a printer mode command P2 indicating that the output is a print is set corresponding to the high-vision read command R2. The parameters x1 and y1 in the subsequent S0 command indicate the reading start position, and x2 and y.
Reference numeral 2 denotes a reading area in mm units. FIG.
Is the reading area and the aforementioned x1, y1, x2, y2
FIG. FIG. 3 shows a document to be read, and the document is placed so that the illustrated reference point matches the reference point of the image sensor. The image sensor performs main scanning in the x direction from the reference point to the right and sub-scans in the y direction from the reference point to the lower side. The read image data is schematically shown in FIG. Then, writing is performed from the pixel a to the pixel b in the image memory of the Hi-Vision device, and the process ends with the last pixel d.

The A command is a command in the reply data, where x and y are the number of horizontal pixels actually output from the image sensor, and y is the number of vertical lines. Main control unit 1
9 receives the code data from the host device, calculates the address of the reading start pixel in the main scanning direction, the number of pixels to be read, and the enlargement / reduction ratio based on the area information. On the other hand, the read address and the number of pixels are set, and the enlargement / reduction ratio is set for the enlargement / reduction unit 14. Similarly, for the sub-scanning direction, the address of the reading start line, the number of lines to be read, and the enlargement / reduction ratio in the sub-scanning direction are calculated.
Assuming that the scanning speed when scaling is not performed is 100%,
The scan speed is calculated from the enlargement / reduction ratio, and the motor control unit 21
, The scanning speed is set. For example, if it is reduced by 50%, the scanning speed becomes 200%, that is, double the speed, and if it is enlarged by 200%, the scanning speed becomes 50%,
That is, the speed becomes half.

Further, the main control unit 19 sets the above-described various reading conditions for each processing unit, and after completing preparation for reading for the host device, transmits the image data to be transmitted to the host device. And instructs the interface unit 16 to switch the transmission data from code data to image data. Then, various preprocessings are performed until the image signal is output from the CCD, starting with lighting of the fluorescent lamp, and a command to start scanning is given to the motor control unit 21. When the reading start line is reached, the reading unit 12 is instructed. Instructs the start of image signal supply.

The image data 17 supplied from the reading section 12 is cut out by the main scanning area control section 13 only on the reading area portion in the main scanning direction based on the value previously set by the main control section 19. The image data that has become only necessary parts is enlarged / reduced by the enlargement / reduction unit 14 based on the value of the enlargement / reduction ratio also set by the main control unit 19.
The image is enlarged / reduced in the main scanning direction and supplied to the sub-scanning area control unit 15.

After receiving the reading start command, the sub-scanning area control unit 15 starts to supply image information to the interface 16 from an effective line in consideration of the delay in the sub-scanning direction of various processes. After transmitting the set number of reading lines, the supply of image information is stopped, and a series of reading operations is completed. Next, taking the case where the code data shown in Table 2 is received as an example, the main scanning and the sub-scanning direction enlargement / reduction for converting the read area designated by using the above-described processing system into the pixel size of the high definition. The process of calculating the rate will be described.

The ratio between the horizontal and vertical lengths of a high-vision display device is set to 16: 9 according to the standard as shown in FIG. However, the number of pixels of a high-definition image is 192 in the horizontal direction as shown in FIG.
0 pixels and 1035 pixels in the vertical direction are defined, which is not 16: 9. Therefore, one pixel in the high-definition monitor can be considered to be not a square as shown in FIG. 7 but a vertically long rectangle as shown in FIGS. Therefore, when a true circle read by an image sensor or the like is displayed on a high-definition monitor, it becomes a vertically long ellipse.

From the above, when the output device is a high-vision monitor, when the reading area is converted into the number of pixels of the high-definition size in consideration of the aspect ratio of the high-vision monitor, what is read as a perfect circle is regarded as a perfect circle. Calculate the enlargement / reduction ratio to be displayed. On the other hand, when outputting to a conventional monitor or printer, one pixel is square unlike a high-vision monitor. In the high-vision reading mode, when the output device is a printer, the enlargement / reduction ratio is calculated based only on the ratio between the reading size and the number of pixels of the high-vision image.

Assuming that the basic resolution of the image sensor in this embodiment is 16 [dot / mm], when the commands and parameters shown in FIG. 11 are received, the size of the read area is 3200 (= 16 ×) in the horizontal direction. 200) pixels, and the vertical direction is 2400 lines (= 16 × 150). Since the pixel size in the horizontal direction of HDTV is 1920 pixels as shown in FIG. 6, when the reduction ratio is calculated based on the horizontal direction, 60% (= 1920 ＝ 3200 × 10
0). However, as shown in FIG. 9, the HDTV pixel size based on the horizontal direction is 1: 1.04.
3, so that the image is further reduced by 96% in the vertical direction. Therefore, the final reduction ratio is 60% in the horizontal direction and 58% in the vertical direction (= 60 × 0.96). As a result, when this reading area is displayed on the basis of the horizontal direction, the reading area becomes 1 in the horizontal direction.
920 pixels, vertical direction 1392 (= 2400 × 0.58)
A line display area is required. However, the effective display line number of the high-definition screen is 1035 lines, and it is impossible to display the entire reading area. Therefore, it becomes unnecessary to read a line that can be displayed only on the display lines after 1036 lines. Therefore,
A value obtained by dividing 1035 by 0.58, that is, a line after 1785 lines is not read. That is, 178
Data after 6 lines is truncated.

On the other hand, depending on the designation of the reading area, the effective reading area after enlargement / reduction may be larger. That is, the reading area may be smaller than the display area. For example, when the code data as shown in FIG. 13 is received, the number of lines in the designated reading area is 1120 lines with respect to 1785 effective reading lines calculated from the reduction ratio. In such a case, the read image size returned from the image sensor to the host device is 1920 in width and 650 in height (= 1120 × 0.
58), and no extra data is transmitted. If it is desired to always keep the number of pixels of the high definition, the reading area may be extended. Also, when the instruction from the host device is based on the vertical direction, the same processing is performed.

Further, in order to make the most of the readable range of the image sensor, the original is read vertically and written in a high-definition image memory in the horizontal direction. FIG. 4 shows the relationship between the original and the reading position in this case. The reference point of the original corresponding to the reference point of the image sensor is as shown in the figure. The image sensor performs main scanning downward in the y direction from the reference point and sub-scans in the x direction leftward from the reference point. The read image data is written into the image memory of the Hi-Vision device shown in FIG. 6 from the b pixel to the d pixel, and ends with the final pixel c.

In this application, x1 and x2 in FIG.
y2 is made to correspond to the main scanning direction, the enlargement / reduction ratio is calculated by the same procedure as described above, and the pixel density conversion processing is performed. Hereinafter, the reading control operation of the main control unit 19 of the present embodiment for performing the reading by moving the optical scanning means in the sub-scanning direction (vertical direction) of the Hi-Vision screen as shown in FIG. The description will be given according to the flowchart shown in FIG. First, it waits for input of code data from the interface. When the code data is input, FIG.
The command parameters in the format shown in FIG. Next, the reading area is calculated by multiplying the size x2 and y2 of the reading designated area by the basic resolution 16 to obtain the number of vertical and horizontal pixels AH and AV.

Next, the designation of the reading method in the command set is identified, and the command is normally read R1, that is, in the case of outputting the screen as it is read without enlarging or reducing the screen, the value xy of the number of pixels to be read is used. Are set to AV and AH, respectively, and the processing shifts to the reading state shown in FIG. If the command is a high-vision reading R2, that is, if the command is to be displayed after being enlarged or reduced in accordance with the high-vision screen, the reference direction is identified.

If the horizontal direction reference K1, that is, the horizontal direction is to be completely displayed on the high-definition screen, 1920 is divided by the number of pixels AH in the horizontal direction to obtain the horizontal scaling ratio ZH, and the vertical scaling ratio ZV is obtained. Also common. Also, if the vertical reference K2, that is, the vertical direction is to be completely displayed on the HDTV screen, 1035 is divided by the number of pixels AV in the vertical direction to obtain the vertical scaling ratio ZV, and the horizontal scaling ratio ZH is also obtained. Make it common.

Furthermore, if the display is full horizontal / vertical independent K3, that is, if the display is to be full of the HDTV screen, the horizontal scaling factor ZH is obtained by dividing 1920 by the number AH of pixels in the horizontal direction. ZV is 1035, the number of pixels AV in the vertical direction
Divide by to find. Next, the mode is identified. If the mode is the monitor mode, the original vertical scale factor ZV is multiplied by 0.96, a new scale factor ZV is set, and pixel ratio compensation is performed.

Thereafter, the number of pixels in the designated area is multiplied by the enlargement / reduction ratio to obtain the number x of pixels to be read in the horizontal direction and the number y of pixels to be read in the vertical direction. If the obtained number of pixels is a displayable value, that is, x exceeds 1920, x is limited to 1920, and if y exceeds 1920, y is limited to 1035. After that, the processing shifts to the reading state in FIG. In this reading state, the number of horizontal read pixels x and the number of vertical read pixels y are transmitted to the host device via the interface 16. Next, the interface data bus is switched to the image information side. Then, the main scanning control unit 1
3, a reading start position and a reading area in the main scanning direction are set, a horizontal scaling ratio ZH is set in the scaling unit, and a vertical scaling ratio ZV is set in the motor control unit. Subsequently, the fluorescent lamp 3 is turned on to perform preprocessing, and reading is started. Upon the start of the reading, the image sensor performs the reading operation according to the clock generated by the main control unit 19, and the stepping motor 19 moves the optical scanning unit according to the stepping clock. When the optical scanning unit reaches the reading area, the main control unit supplies reading start and end timing signals to the sub-scanning region control unit 15 and the reading start unit 13 to convert and output image data.

When the optical scanning means completes the sub-scanning and returns to the original position, the set data is reset and reset to the initial state. As shown in FIG. 4, when an image is read by moving the optical scanning means in the main scanning direction (horizontal direction) of the high-definition screen, a vertical enlargement / reduction ratio ZV is set in the enlargement / reduction unit. What is necessary is just to set the horizontal enlargement / reduction ratio ZH in the motor control unit. This configuration corresponds to the second aspect of the present invention.

[0025]

As described above, according to the present invention, since the pixel ratio is compensated simultaneously with the reduction or enlargement, efficient processing can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a flatbed scanner.

FIG. 2 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 3 is a diagram showing a reading area and a scanning direction when reading a vertically long document.

FIG. 4 is a diagram showing a reading area and a scanning direction when reading a landscape original.

FIG. 5 is a diagram illustrating a screen of a high-definition display device.

FIG. 6 is a diagram showing an image memory of the high-vision device.

FIG. 7 is a diagram illustrating an aspect ratio of one pixel in an NTSC system or a printer.

FIG. 8 is a diagram illustrating an aspect ratio of one pixel in a high-definition display device on a vertical basis.

FIG. 9 is a diagram illustrating an aspect ratio of one pixel in a high-definition display device on a horizontal basis.

FIG. 10 is an explanatory diagram showing commands for received data and transmitted data.

FIG. 11 is a diagram illustrating an example of received data.

FIG. 12 is a diagram showing transmission data corresponding to FIG. 11;

FIG. 13 is a diagram illustrating another example of received data.

FIG. 14 is a diagram showing transmission data corresponding to FIG.

FIG. 15 shows a flowchart of a main control unit.

FIG. 16 shows a flowchart of the main control unit following FIG. 15;

[Explanation of symbols]

 9 CCD line sensor 12 reading unit 14 enlargement / reduction unit 19 main control unit 20 stepping motor 21 motor control unit

Claims (1)

(57) [Claims] An optical scanning unit that scans a designated reading area in a main scanning direction; a stepping motor that drives the optical scanning unit in a sub-scanning direction; a motor control unit that supplies a stepping pulse to the stepping motor; In an image reading apparatus having an enlargement / reduction unit for enlarging or reducing image data in a main scanning direction and a monitor composed of rectangular pixels for outputting an image of a designated area, the image of the designated area is When displaying on a screen, a control unit for setting a value obtained by multiplying an enlargement ratio or a reduction ratio in the main scanning direction of the monitor by a pixel ratio compensation coefficient is provided for the enlargement / reduction unit. Image reading device.