JP3071049B2 - 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 for reading an image using an image sensor.

[0002]

2. Description of the Related Art In recent years, a plurality of (three) line sensors are arranged in parallel on one chip, and
Three-line color CCD sensors dyed with G and B organic dyes are commercially available. When this three-line CCD sensor is used, an external buffer memory is required to fill the physical distance between the line sensors arranged in parallel.

In such a three-line CCD sensor, the distance between the line sensors is set to an integral multiple of the size of the pixel in the scanning direction (0.0625 mm in the case of a reading density of 16 dots / mm) (in the above embodiment, (Between each line sensor = 12 lines), the image signals from the line sensors arranged in parallel at the same-magnification reading are output without shifting in the sub-scanning direction through the external buffer memory.

In the case of performing stepless (actually 1% unit) enlargement reading by changing the scanning speed (sub-scanning speed) of the optical system using a three-line color CCD sensor, for example, the sub-scanning speed is increased to 1: 1. When performing double magnification (200% magnification) by halving the reading, the physical distance between the line sensors is doubled (12 lines × 2 times = 24 in the above embodiment).
Line).

However, in the case of performing the enlargement reading, it is sufficient if the enlargement can be performed by reading the image data of 24 lines, which is an integer value, as in the case of, for example, 2 times enlargement. When this operation is performed, 12 lines × 1.35 times = 16.2 lines, and image data for 16.2 lines must be read. When a line sensor is used, reading can be performed only in units of one line. Therefore, image data for 0.2 lines could not be read.

In the enlargement processing of the conventional image reading apparatus, since the image data corresponding to the decimal value is processed, for example, 135%
In the case of enlargement, enlargement processing has been performed by reading image data for 16 lines or image data for 17 lines, which is an approximate value of 16.2, and using the image data as image data after enlargement.

[0007]

In the conventional image reading apparatus described above, the error during the enlargement processing becomes very large, and there is no reproducibility that the image after the enlargement processing becomes an image of the designated magnification. Had a point. The present invention has been made in view of the above problems, and aims to reduce errors in the enlargement processing and improve the reproducibility of an image after the enlargement processing.

[0008]

SUMMARY OF THE INVENTION The present invention provides a plurality of line sensors for reading image information, a buffer memory corresponding to each line sensor for correcting a physical distance between the plurality of line sensors, Te at the line sensor in the image reading apparatus that includes a timing generation unit corresponding to the line sensors for driving, when performing the enlargement process in the subscanning direction of the designated magnification <br/>, than said specified magnification Big and each
Increase the magnification so that the number of read lines between line sensors is an integer
An enlargement reading unit for performing an enlargement reading of an image based on the data, and data read by the enlargement reading unit as the specified magnification.
And a reduction processing unit for performing the reduction processing as described above.

[0009]

According to the present invention, the magnification is selected so as to be closest to the designated magnification and larger than the number of magnifications, and to further increase the number of read lines between the line sensors to an integer. An error can be reduced by performing reading and performing a reduction process of thinning out and reducing the image to an actual magnification after the enlarged reading.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the image processing apparatus according to the present invention will be described with reference to FIGS. 1, 2, 3, 4, and 5. FIG. FIG. 1 is a block diagram showing one embodiment of the image reading apparatus of the present invention, FIG. 2 is a block diagram showing one embodiment of a three-line color CCD sensor used in the present invention, and FIG. 3 is an image processing apparatus to which the present invention is applied. FIG. 4 is a functional block diagram showing an embodiment of the configuration of the image processing circuit, FIG. 4 is a time chart showing an embodiment of a signal for controlling line data from a three-line color CCD sensor of the present invention, and FIG. It is a schematic diagram which shows one Example of the algorithm of a reduction process.

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 which is placed on the platen glass.
A document pressing plate for pressing the platen glass 2 from above is provided with a light source (fluorescent lamp, halogen lamp, etc.) 5 for irradiating the document 1 placed on the platen glass 2 with light.
Is a first mirror that reflects light reflected from the document 1 illuminated from the light source 4 to a second mirror described later, and 10 is a first mirror composed of the light source 4 and the first mirror 5. A unit 6 is a second mirror that reflects reflected light guided from the first mirror to a third mirror described later, and 7 is a reflected mirror that reflects reflected light guided from the second mirror to a lens described later. A third mirror 11 for reflecting light is a second mirror unit composed of a second mirror 6 and a third mirror 7, and a three-line color CCD 8 is provided for reflecting light guided by the third mirror. A lens that forms an image on the sensor,
Reference numeral 9 denotes a three-line color CCD sensor in which three line sensors are arranged in parallel on one chip, and each line sensor is dyed with one of R, G, and B organic dyes. The first mirror unit 10 and the second mirror unit 11 are driven by a stepping motor (not shown) and a driving mechanism (not shown) for transmitting the power of the stepping motor at a scanning speed of 2: 1 in the arrow direction A (the (Scan direction).

FIG. 2 shows the three-line color CCD shown in FIG.
In the configuration diagram of the sensor 9, a line sensor 2 having 14 μm × 14 μm as one pixel and having an effective pixel number of 5000 pixels
1, 22, 23 (short side of A3 size is 16 dots / mm
3) are arranged in parallel on the chip with a distance of 168 μm (12 lines), and each line sensor is dyed with any one of R, G and B organic dyes. In this embodiment, the line sensor 21 is set to R
(Red), G (green) for line sensor 22, line sensor 2
3 is B (blue). Each line sensor is driven independently and synchronously.

When reading is performed with the above configuration, the distance between the line sensors on the three-line color CCD sensor 9 is 12 lines (14 .mu.m.times.12 lines = 168 .mu.m) in the sub-scanning direction. When viewed from the line sensor 21 (R) that scans the image in advance corresponding to A), the line sensor 22 (G) and the line sensor 23
The distance from (B) is 12 lines (168 μm) and 2 lines, respectively.
4 lines (336 μm) and each line sensor 2
The reading positions on the original 1 by the reference numerals 1, 22, and 23 are shifted.

Therefore, each of the line sensors 21, 22, 23
In order to achieve synchronization, correction is performed using memories for several lines. The method of the correction will be described with reference to FIG. Of the three line sensors arranged in parallel, in order to synchronize with the line sensor 23 (B) to be read last,
Assuming that the reading density in the sub-scanning direction is 16 dots / mm, in the case of the same-size reading, a buffer memory for 24 lines is provided in the line sensor 21 (R) and the line sensor 22 is provided.
(G) has a buffer memory for 12 lines. Line sensor 21 (R), line sensor 2 to read ahead
When the line sensor 23 (B) reads the same line as the line already read by 2 (G), the data of the same line of each color is read from the buffer memories 33 and 34 in synchronization with the line sensor 23 (B) to obtain the data of the same line. be able to.

A description will be given of a case where enlargement is performed in units of 1% in such a configuration. For example, when performing 2 times enlargement (200% enlargement), the main control unit 39 uses a multiple of a constant 0.5,
In addition, a control constant that is closest to the specified magnification number (arbitrary magnification) and is equal to or greater than that number is obtained. Note that the constant 0.5 is a value such that the number of read lines between the line sensors becomes an integer value. In this example, twice is derived as a control constant using a constant and a specified magnification number. Since there is an interval of 12 lines between each line sensor of the 3-line color CCD sensor, 12 lines ×
2 (control constant) = data for 24 lines only needs to be fetched, and the main control unit 39 controls the motor drive pulse generation unit 310 so that the speed between the line sensors is read at 24 lines. I do. As controlled by the main controller 39, the motor drive pulse generator 310 provides the stepping motor 311 with a pulse corresponding to the speed at which 24 lines can be read between the line sensors,
The control in the sub-scanning direction is performed. Therefore, the same line as the line already read by the line sensor 21 (R) and the line sensor 22 (G) that is read earlier is
When (B) is read, 48 lines of data are read from R and 24 lines of data are read from G and stored in the buffer memories 33 and 34.

In this embodiment, the line buffer memory 3
Reference numerals 3 and 34 each have only a buffer memory for 24 lines and 12 lines, and read 48 lines and 24 lines.
Since the line data cannot be stored, the main control unit 39 reduces the read area in the main scanning direction,
Control is performed such that a read area control signal is output to the various timing generators 38 so as to reduce the effective data in the data of one line so that the line data of each of the lines 24 and 24 enters the corresponding buffer memory. Do.

As shown in the time chart of FIG. 4, the various timing generators 38 provide a read area control signal indicating which position of the data 40 output from the three-line color CCD sensor 9 is valid. 41 is output to each of the input gates 30, 31, and 32. For example, if one half of one line from the end is enabled, data for 48 lines is stored in the 24-line buffer memory, and data for 24 lines is stored in the 12-line buffer memory.

Line sensor 21 (R) to read ahead
When the line sensor 23 (B) reads the same line as the line already stored in the read buffer memories 33 and 34 by the line sensor 22 (G), the main control unit 39 synchronizes with the line from the buffer memories 33 and 34 Read the data of the line. At the same time, the main control unit 39 sends the output gates 35, 36,
37 is opened.

Next, the case of performing 1.35 times magnification (135% magnification) will be described. The main control unit 39 is a multiple of the constant 0.5 and is closest to the specified magnification (arbitrary magnification).
Find a control constant that is at least that number. In this example, 1.5
The fold is derived as a control constant. 3 line color CC
There are 12 lines between each line sensor of D sensor,
12 lines x 1.5 when trying to enlarge control constant times
(Control constant) = data for 18 lines only needs to be fetched.
For 10, control is performed so that the speed between each line sensor is read at 18 lines. As controlled by the main controller 39, the motor drive pulse generator 310 supplies a pulse corresponding to a speed at which the line sensors can read between 18 lines to the stepping motor 311 to control the sub-scanning direction. Therefore, the same line as the line already read by the line sensor 21 (R) and the line sensor 22 (G) that is read earlier is read by the line sensor 23 (B).
Is read, 36 lines of data from R, G
, Data for 18 lines are read and stored in the buffer memories 33 and 34.

In this embodiment, the line buffer memory 3
Reference numerals 3 and 34 each have only 24 lines and 12 lines of buffer memory, and read 36 lines and 18 lines.
Since the line data cannot be stored, the main control unit 39 reduces the reading area in the main scanning direction,
The various timing generators 38 are controlled so as to output a read area control signal for reducing the effective data in the data of one line so that the line data of each of the lines 18 and 18 enters the corresponding buffer memory. Do.

As shown in the time chart of FIG. 4, the various timing generators 38 provide a read area control signal indicating which position of the data 40 output from the three-line color CCD sensor 9 is valid. 41 is output to each of the input gates 30, 31, and 32. For example, if two thirds of one line from the end is enabled, data for 36 lines is stored in the 24-line buffer memory, and data for 18 lines is stored in the 12-line buffer memory.

Line sensor 21 (R) to read ahead
When the line sensor 23 (B) reads the same line as the line already stored in the read buffer memories 33 and 34 by the line sensor 22 (G), the main control unit 39 synchronizes with the line from the buffer memories 33 and 34 Read the data of the line. However, if you open the output gate as it is, it will be the same as 1.5 times magnification,
The main control section 39 thins out the image data so that the number becomes 1.35 times.
In this example, the main control unit 39 derives the reduction constant from 1.35 (designated magnification) /1.5 (control constant) = 0.9 (reduction constant). That is to say, by performing a 0.9-fold enlargement (reducing to 90%) of a 1.5-fold enlargement, 1.
Achieve 35 times magnification. (12 lines × 1.5 (control constant) × 0.9 (reduction constant) = 16.2 lines) The main control unit 39 determines that the reduction constant derived by (designated enlargement magnification) ÷ (control constant) ( Based on (0.9 in this example), the various timing generators 38 are controlled so as to reduce to 90%.

The various timing generators 38 output the line data read out from the 24-line buffer memory 33, the 12-line buffer memory 34 and the input gate 32 (B) into the output gate 35 for one line out of the 10 line data. , 36 and 37 are not passed. That is, one line is thinned out for every ten lines.

Next, this thinning will be described with reference to FIG. FIG. 5 is a schematic diagram showing the algorithm of the reduction process. For example, when the reduction is performed to 90% (FIG.
(A)), the main control unit 39 obtains 100% −90% = 10 (multiple variable), and the 24 line buffer memories 33 and 12
Each time data is read from the line buffer memory 34 and the input gate 32 (B), a multiple variable is added by an adding unit (not shown) in the main control unit 39. When the sum total (counter value) exceeds 100, carry is performed. Generate a signal,
Only the number less than 100 from the total sum is stored as the total sum.

The various timing generators 38 include the main controller 3
When the carry signal from 9 becomes active, the output gates 35, 36 and 37 are closed to prevent the passage of line data. In the case of reduction to 90% of the present example, up to ninth line passes through the output gates 35, 36, and 37, and when the tenth line is read, a carry signal is generated from the main control unit 39 to generate various timings. The data of the tenth line is output from the output gates 35, 36, 3
7 so as not to pass through.

Next, a case where the image is reduced to 70% (FIG. 5)
(B)), the main control section 39 calculates 100% −70% = 30 (multiple variable) and performs the same processing as the above processing. 7 of this example
When the data is reduced to 0%, when the data of the fourth, seventh, and tenth lines of the ten-line data is read, a carry signal is generated from the main controller 39, and the various timing generators 38 are provided. Output gates 35, 36, 37
Is controlled not to pass through.

The configuration described above shows one embodiment of the present invention, and the memory capacity of the buffer memories 33 and 34 may be a memory capacity corresponding to the maximum magnification. Then, the input gates 30, 31, 32 and a control unit for controlling the input gates are not required, and the entire area can be read without dividing the read area in the main scanning direction. As described above, the magnification reading is selected by selecting a magnification that is closest to the designated magnification, is larger than the number of the magnification, and furthermore, the number of read lines between each line sensor is an integer. By performing the reduction process of performing the thinning-out reduction so as to obtain the actual magnification after the enlargement reading, the error can be reduced, and the reproducibility of the image after the enlargement process can be improved.

[0028]

According to the present invention, it is possible to reduce errors in the enlargement processing and improve the reproducibility of the image after the enlargement processing.

[Brief description of the drawings]

FIG. 1 is a configuration showing an embodiment of an image reading apparatus of the present invention.

FIG. 2 is a diagram showing one embodiment of a three-line color CCD sensor used in the present invention.

FIG. 3 is a functional block diagram illustrating an embodiment of a configuration of an image processing circuit of the image processing apparatus to which the present invention has been applied.

FIG. 4 is a time chart showing one embodiment of a signal for controlling line data from a three-line color CCD sensor according to the present invention.

FIG. 5 is a schematic diagram showing an embodiment of an algorithm of a reduction process according to the present invention.

[Explanation of symbols]

 9 3 line color CCD sensor 21 line sensor (R) 22 line sensor (G) 23 line sensor (B) 30 input gate (R) 31 input gate (G) 32 input gate (B) 33 24 line buffer memory 34 12 lines Buffer memory 35 Output gate (R) 36 Output gate (G) 37 Output gate (B) 38 Various timing generators 39 Main controller

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-109966 (JP, A) JP-A-1-19864 (JP, A) JP-A-1-101062 (JP, A) JP-A-5-106 22520 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 1/04-1/207

Claims (3)

(57) [Claims] 1. A plurality of line sensors for reading image information; a buffer memory corresponding to each line sensor for correcting a physical distance between the plurality of line sensors; and a buffer memory for driving the plurality of line sensors. at a image reading device that includes a timing generation unit corresponding to the line sensors, when performing the enlargement process in the subscanning direction for a specified magnification of the designated
Read line larger than magnification and between each line sensor
An enlargement reading unit that performs enlarged reading of an image based on a magnification whose number is an integer, and a reduction processing unit that performs reduction processing on the data read by the enlargement reading unit so as to have the specified magnification. Characteristic image reading device. 2. An enlargement reading section corresponding to each of the plurality of line sensors and having an input gate section for passing only a data valid area of one line data output from the line sensor. Item 2. The image reading device according to Item 1. 3. The image reading apparatus according to claim 1, wherein the reduction processing is performed by thinning out the data read by the enlargement reading section at an output gate section.