JPH05284284A - Original reader - Google Patents

Abstract

PURPOSE:To eliminate the need for layout of an approach distance and a deceleration distance of a scanner by providing a picture processing means magnifying picture data from the scanner for matching with an original scanning speed of the scanner and obtaining picture data of a same magnification factor to the reader. CONSTITUTION:A picture processing board 3 is provided with gate arrays 8, 9 or the like, a ROM, a RAM and a pulse generating circuit and the gate array 8 applies processing such as shading correction and MTF correction or the like to a picture signal from the picture read board and outputs the result to the gate array 9. The gate array 9 is a magnification gate array and magnifies a picture signal from the gate array 8 in the main scanning direction. Then nonmagnification write picture is obtained by magnifying picture data read at each position at a prescribed read picture element pitch for an original on an original platen by a CCD so as to be written at the same picture element pitch as a read picture element pitch by the writer through the magnification gate array 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading device for reading a document on a document table.

[0002]

2. Description of the Related Art Conventionally, a digital type original reading device and an analog type original reading device scan a document on a platen at a constant speed by moving a scanner at a constant speed by a scanner motor. And
The leading edge of the original on the platen needs a rise time until the scanner rises to a constant speed after starting movement, and during this rise time, the scanner runs before the leading edge of the original on the platen There is a distance called the distance. In addition, the rear end of the original on the platen also needs a deceleration time until the scanner decelerates from a certain speed and stops after scanning the original. A distance called a deceleration distance is provided for traveling behind the end.

[0003]

In the above document reading apparatus, since the document on the platen is scanned and read at a constant speed, the scanner is moved to the leading end of the document on the platen until the scanner rises at a constant speed. It requires a run-up distance and a deceleration distance on the trailing edge of the original on the platen until the scanner decelerates from a certain speed and stops after scanning the original. .. Moreover, since the run-up distance and deceleration distance change depending on the size of the above-mentioned constant speed of the scanner, a layout according to the scanning speed of the scanner is required when designing the layout of the scanner. And the place according to the deceleration distance is needed.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the above-mentioned drawbacks and to provide a document reading apparatus which can eliminate the layout of the approach distance and deceleration distance of the scanner.

[0005]

In order to achieve the above object, the invention according to claim 1 is an original reading device for reading an original on a platen with a scanner, in accordance with the original scanning speed of the scanner. The original document reading apparatus according to claim 1 is provided with an image processing means for changing the image data from the scanner to obtain image data of the same magnification. It is provided with a control means for scanning the document with acceleration while reading the document.

[0006]

According to the first aspect of the invention, the image processing means scales the image data from the scanner in accordance with the document scanning speed of the scanner to obtain image data of the same magnification. According to a second aspect of the present invention, in the document reading apparatus according to the first aspect, the control means causes the scanner to scan the document with acceleration while reading the document.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a circuit configuration of an embodiment of the present invention.
This embodiment has an image processing unit (IPU) 3 including an optical control plate 1, a main control plate 2 and an image processing plate, and the optical control plate 1 is an optical control microcomputer (CPU).
4, a scanner motor 5 and an encoder 6. The main control board 2 has a CPU 7, and the image processing board 4 has dedicated LSIs 8 and 9 called gate arrays. FIG. 3 shows a traveling body portion of the scanner in this embodiment. The first traveling body 10 and the second traveling body 11 are moved by the scanner motor 5
The document is driven by a double-sided drive method through the wire 12 of the book to reciprocate, and the document on the fixed document table is scanned at the time of forward (or backward) movement.

FIG. 2 shows the scanner of this embodiment. The document table 13 is fixed, and a document is manually placed by a user or automatically fed by an automatic document feeder (ADF) (not shown). In this case, the leading edge of the document is aligned with the reference white plate 14. The first traveling body 10 is equipped with a light source 15, which is a fluorescent lamp, a counter reflection plate 16 and a first mirror 17, and the second traveling body 11 is equipped with a second mirror 18 and a third mirror 19. The light emitted from the fluorescent lamp 15 hits the original document on the original table 13 with the assistance of the counter reflecting plate 16, and the reflected light is reflected by the first mirror 17 and the second mirror 1.
8. After passing through the third mirror 19, a lens 20 forms an image on a solid-state reading component 21 called CCD, and the CCD 21 photoelectrically converts it into an image signal. The original document on the original table 13 is scanned by the forward movement of the first traveling member 10 and the second traveling member 11 and read by the CCD 21 line by line. The fluorescent lamp 15 is provided with a heater 22 and a thermistor, is heated by the heater 22, and its temperature is detected by the thermistor.

FIG. 4 shows the structure of the optical control plate 1 and its peripheral portion. In the optical control board 1, a one-chip CPU 4 is connected to a CPU 7 in the main control board 2 via a serial interface (I / F) 23, and the CPU 4 is installed in the main control board 2 via a serial I / F 23. CPU7
Exchange data with. CPU4 is the main control board 2
Data of the set scaling ratio is given from the CPU 7 in the inside through the serial I / F 23, data of the rotation speed of the scanner motor 5 is calculated from the data of the set scaling ratio, and is output to the frequency dividing circuit / rotation direction detection circuit 25. To do.

The frequency divider / rotation direction detection circuit 25 is a CPU
Based on the data of the rotation speed of the scanner motor 5 from 4, the reference clock is divided to generate a clock having a frequency for rotating the scanner motor 5, and a current is supplied to the scanner motor 5 by the PWM signal based on this clock. To rotate the scanner motor 5. The encoder 6 detects the rotation speed of the scanner motor 5 and feeds back a clock having a frequency corresponding to the rotation speed to the frequency dividing circuit / rotation direction detecting circuit 25. The frequency divider / rotation direction detection circuit 25 controls the pulse width of the PWM signal by the clock from the encoder 6, and controls the rotation speed of the scanner motor 5 to a rotation speed corresponding to the rotation speed data of the scanner motor 5 from the CPU 4. To do.

Further, the image reading plate 24 outputs the image data from the CCD 21 to the image processing plate 3, and the image processing plate 3
Processes the image signal as described later and outputs it to the optical control plate 1. Further, the CPU 4 in the optical control plate 1 is the fluorescent lamp 1
5 is controlled via the ballast 26, and the heater 2 is controlled by using the temperature detection signal from the thermistor which detects the temperature of the fluorescent lamp 15.
By controlling 2, the temperature of the fluorescent lamp 15 is controlled to a predetermined temperature. The scanner HP sensor 28 is the traveling body 10, 1
Detecting that 1 is in the home position, C
The PU 4 controls the rotation of the scanner motor 5 by using the detection signal from the scanner HP sensor 28, and
It controls the reciprocating motion of 0 and 11. Further, the CPU 4 controls the ADF 29 via the serial I / F and the optical fiber.

FIG. 5 shows the structure of the image processing plate 3. The image processing plate 3 includes gate arrays 8, 9, 30 to 32, ROM
33, a RAM 34, and a pulse generation circuit 35, and the gate array 8 performs processing such as shading correction and MTF correction on the image signal from the image reading plate 24 and outputs the processed image signal to the gate array 9. Pulse to generate a drive clock for the CCD 21 and output the clock to the image reading plate 24, and at the same time control the timing of each part.

The gate array 9 is a gate array for scaling, and scales the image signal from the gate array 8 in the main scanning direction. The main scanning direction means that the CCD 21 is the document table 1
3 is the direction of one line for reading the original, and the sub-scanning direction is the direction in which the first traveling body 10 and the second traveling body 11 are moved by the scanner motor 5. As shown in FIG. 6, in a 9, the CCD 21 writes the image data obtained by reading the document on the document table 13 at respective positions a1, a2, a3 ... With a predetermined reading pixel pitch by the scaling gate array 9. If the apparatus performs scaling so that writing is performed at the same pixel pitch as the reading pixel pitch, a written image of equal size can be obtained.

For example, if the length of 10 pixels of the CCD 21 is 8
If the image data is read from the original at each of the positions a1 ′, a2 ′, a3 ′, etc. and written at the same pixel pitch (pixel pitch of the CCD 21) as the normal size, the original is reduced to 80%. I wrote it. Also, CC
The length of 10 pixels of D21 is divided into 14 equal parts and each position a
If the image data is read from the original with 1 ", a2", a3 ", and written at the same pixel pitch as the normal size, the original is enlarged to 140% and written. Positions a1 ′, a2 ′, a3 ′, ..., A where the length of the pixel is divided into 8 equal parts or 14 equal parts
1 ″, a2 ″, and a3 ″ do not have read pixels of the CCD 21 (the read pixels may happen to overlap), so these positions a1 ′, a2 ′, a3 ′ ..., a
Image data cannot be obtained from the CCD 21 for 1 ", a2", and a3 ".

Therefore, in this embodiment, those positions a
1 ', a2', a3 '..., a1 ", a2", a3 "
It is assumed that there is a pixel to be read by the CCD 21 (there is a virtual sample point of the CCD 21), and the scaling gate array 9 outputs pixel data of the virtual sample point two each before and after the virtual sample point in the image signal from the gate array 8. Calculated from the pixel data of. In this way, the scaling gate array 9 scales the image signal from the gate array 8 by changing the pixel pitch in accordance with the scanning speed of the scanner from the read pixels of the CCD 21, and sets the scaling factor (etc. Double or reduced, enlarged image signal is obtained. The scaling gate array 9 is used for a digital copying machine, and the scaling ratio can be arbitrarily set between 25% and 400% for use.

The image signal from the scaling gate array 9 is subjected to halftone processing and binarization processing by the gate array 30. The gate array 32 detects the mark area with respect to the image signal from the gate array 30,
1 performs character / halftone separation and hollowing on the image signal from the gate array 30 and outputs it to the optical control plate 1 via the gate array 8.

The scanner control method by the optical control plate 1 of this embodiment is a method of eliminating the run-up distance and deceleration distance of the scanner as in the prior art and scanning the original even when the scanner is out of the constant velocity region. Controls the scanner as shown in FIG. That is, the optical control plate 1 is the traveling body 10,
While 11 is located at the home position, the scanner motor 5 is accelerated in the acceleration region from the point A to the point C where the scanner (traveling body 10, 11) reaches a predetermined scanning speed. At that point, the scanner reaches the leading edge of the document on the document table 13 and starts scanning from the leading edge of the document. The optical control plate 1 controls the scanner motor 5 to a constant speed in a constant speed region from when the scanner reaches a predetermined scanning speed at the point C to when it reaches the point D near the rear end of the document on the document table 13. In the constant velocity area, the scanner continues scanning the document.

Next, the optical control plate 1 decelerates the scanner motor 5 in the deceleration area from the point where the scanner reaches the point D to the point F (stop point), and the scanner moves the document table at the point E in the middle of the deceleration area. When the trailing edge of the document on 13 is reached, scanning of the document is completed. Further, the optical control plate 1 reverses the scanner motor 5 until the scanner stops at the point F and then returns to the home position, thereby returning the scanner to the home position.

As described above, since the scanner does not scan the document at a constant speed while the document is being read, the magnification of the image signal from the scanner varies from the constant magnification on the leading end side and the trailing end side of the document. The scaling gate array 9 scales the image signal from the gate array 8 so that the magnification is constant over the entire document.

That is, the scanning speed when the scanner passes the constant velocity region from point C to point D is 120 mm / se.
c and the speed when the scanner passes point B is 30
The image read at the point B of the scanner is 400% larger than the image read at the constant velocity area from the point C to the point D of the scanner. Therefore, the scaling gate array 9 performs 25% reduction processing on the image signal from the gate array 8 so that the portion at point B has the same magnification as the portion in the constant velocity region from point C to point D. To do. Similarly, the scaling gate array 9 has the same magnification as the image signal from the gate array 8 in the acceleration region from point B to C and in the constant velocity region from point C to D. As described above, the reduction process is performed while sequentially reducing the reduction ratio according to the scanning speed of the scanner. Therefore, the image signal from the gate array 8 includes 10 parts in the constant velocity region from point C to point D.
As 0%, the acceleration region from point B to point C is 400
The magnification that has been sequentially changed from 100% to 100% is changed to 100% in the acceleration region from the point B to the point C by the magnification changing gate array 9.

Further, the operation speed when the scanner passes the constant velocity region from point C to point D is 120 mm / sec, and the speed when the scanner passes point E is 30 mm.
/ Sec, and the read image at the point E of the scanner is 400% larger than the read image in the constant velocity region from the point C to the point D of the scanner. Therefore, the scaling gate array 9 outputs E to the image signal from the gate array 8.
In the point portion, 25% reduction processing is performed so that the magnification is the same as that in the constant velocity area portion from point C to point D. Similarly,
The scaling gate array 9 magnifies the image signal from the gate array 8 so as to have the same magnification in the deceleration region from point D to point E as in the constant velocity region from point C to point D. Is sequentially reduced from 100% according to the scanning speed of the scanner to perform the reduction processing. Therefore, the gate array 8
The image signal from No. 1 had a magnification that the deceleration region from point D to point E changed sequentially from 100% to 400%, but it was decelerated from point D to point E by the scaling gate array 9. The entire area is scaled to 100%.

When a manuscript is read by changing the magnification instead of reading the same size, the CPU 4 rotates the scanner motor 5 based on the data of the set magnification given from the CPU 7 in the main control board 2 via the serial I / F 23. Since the speed data is calculated and output to the frequency dividing circuit / rotation direction detecting circuit 25, the scanning speed in the constant velocity region from the point C to the point D of the scanner becomes the scanning speed corresponding to the set magnification. Then, similarly to the case where the magnification changing gate array 9 reads an original at the same magnification, a portion of the acceleration region from the point B to the point C and the deceleration region from the point D to the point E with respect to the image signal from the gate array 8. The portion of is zoomed according to the scanning speed of the scanner, and all from point B to point E are image signals of the set magnification.

[0023]

As described above, according to the first aspect of the present invention, in the original reading device for reading the original on the original table by scanning with the scanner, the image data from the scanner is synchronized with the original scanning speed of the scanner. Since the image processing means for obtaining the image data of the same magnification by changing the magnification of is provided, the image signal of the same magnification can be obtained even if the scanning speed of the scanner changes during the reading of the document, and the approach distance and deceleration of the scanner can be obtained. The distance layout can be eliminated.

According to the second aspect of the present invention, the original reading apparatus according to the first aspect further includes a control means for causing the scanner to scan the original with acceleration during the reading of the original. Even if the scanning speed of the scanner changes while scanning the original, it is possible to obtain an image signal with the same magnification, eliminate the need for the layout of the run-up distance and deceleration distance of the scanner, and shorten the overall length of the scanner. Can be made small.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the present invention.

FIG. 2 is a front view showing the scanner of the embodiment.

FIG. 3 is a perspective view showing a traveling body portion of the scanner in the embodiment.

FIG. 4 is a block diagram showing a configuration of an optical control plate and its peripheral portion in the embodiment.

FIG. 5 is a block diagram showing a configuration of an image processing plate in the embodiment.

FIG. 6 is a diagram showing a scaling principle of a scaling gate array in the embodiment.

FIG. 7 is a diagram showing operation timing of the scanner in the embodiment.

[Explanation of symbols]

 1 Optical control board 2 Main control board 3 Image processing board

Claims (2)

[Claims] 1. A document reading apparatus for reading a document on a platen by scanning with a scanner, image processing for scaling image data from the scanner according to a document scanning speed of the scanner to obtain image data of the same magnification. An original reading device comprising means. 2. The document reading device according to claim 1, further comprising control means for causing the scanner to scan the document with acceleration while reading the document.