JPH08195856A - Picture reader - Google Patents

Abstract

(57) [Summary] [Objective] The capacity of the storage device is reduced by reducing the amount of data to be written, and the transfer amount to the host computer is also reduced. [Structure] A flash light source of three primary colors of red, green, and blue, a monochrome two-dimensional light receiving means for receiving reflected light from a document exposed by the flash light source sequentially emitting light, and an output from the two-dimensional light receiving means A / D conversion means for A / D converting
The horizontal direction clock signal for controlling the three-dimensional light receiving means and the AND means for taking the logical sum of the composite blanking pulse, and the storage device for storing the image signal output by the A / D conversion means are provided. The A / D conversion and the writing of the image signal in the storage device are performed using the output signal of the AND means.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a monochrome two-dimensional CC.
The present invention relates to an image reading apparatus using a light receiving unit such as D.

[0002]

2. Description of the Related Art Commonly used image reading devices include flatbed scanners, film scanners,
There is a handy scanner. These scanners
A one-dimensional CCD (line sensor) is used, and a fluorescent lamp or LED is used as a light source.
A two-dimensional flat document is read by automatically moving D (manually in the case of a handy scanner).

Therefore, it takes a long time to read depending on the size of the original. In addition, a drive motor and a drive circuit for moving the one-dimensional CCD are required, and high accuracy is required when assembling them.

As a countermeasure, a monochrome two-dimensional CCD is used to generate red, green, and blue by a flash light source, and the reflected light is received by the two-dimensional CCD, and is received using a horizontal clock signal from the CCD controller. A /
It is conceivable to perform D conversion and save it in a storage device. As a result, the reading time can be significantly shortened as compared with a reading device using a one-dimensional CCD, and a driving motor and a driving circuit are not required, and the assembling process can be greatly shortened.

[0005]

However, when the image is read and the image data is transmitted to the host computer, if a one-dimensional CCD is used, one line of image data is stored and then repeatedly transmitted to the host computer. Data of one image is transmitted. On the other hand, when the two-dimensional CCD is used to operate in accordance with a normal TV system signal, it is necessary to store at least one image data for one color and then transmit it to the host computer due to time problems. There is. Therefore, the capacity of the storage device that can store the data amount of one image point per color is required. Therefore, there is a drawback that the amount of memory used internally increases. Further, if the data amount of one image increases, the transfer amount to the host computer also increases and the transfer time also increases.

The present invention has been made in view of the above problems, and it is an object of the present invention to reduce the capacity of a storage device by reducing the amount of data to be written and also reduce the transfer amount to a host computer.

[0007]

In order to achieve this object, the image reading apparatus of the present invention two-dimensionally reads and reads illumination means for illuminating a document and a document image illuminated by the illumination means. Photoelectric conversion means for outputting an analog image signal according to the brightness and A / A for the analog image signal
A / D conversion means for D-converting and outputting a digital image signal; photoelectric conversion means control means for controlling the photoelectric conversion means to output a horizontal clock signal and a composite blanking signal; and a horizontal clock signal and a composite blank It has AND means for taking the logical sum of the ranking signal and a storage device for storing the digital image signal in synchronization with the output signal of the AND means.

[0008]

In the image reading apparatus having the above structure, the image signal is written to the storage device in synchronization with the logical sum signal of the horizontal direction clock signal and the composite blanking pulse. Even when used, it is possible to reduce the capacity of the storage device per image per color, and at the same time to shorten the time required for transfer to the host computer.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block connection diagram showing an embodiment of an image reading apparatus according to the present invention.

In FIG. 1, the image reading apparatus comprises an image pickup section 2 and a control section 9. Reference numeral 1 is a document to be read. In addition, the host computer 17
Sends and receives commands and statuses to the image reading device, and displays received image data.

The image pickup unit 2 comprises an optical system 3 and a two-dimensional monochrome CCD.
4, CCD controller 5, RG that emits red, green and blue colors
It is composed of a B strobe 6, a strobe controller 7, and a switch 8 for instructing the start of image capturing. The RGB strobe 6 is composed of a Xe tube to which a red filter is attached, a Xe tube to which a green filter is attached, and an Xe tube to which a blue filter is attached. The control unit 9 uses the FRM_OK signal generation circuit 10, AN
The D circuit 11, the A / D converter 12, the FIFO memory 13, the MPU 14, the decoding circuit 15, and the SCSI controller 16 are included.

The FRM_OK signal generating circuit 10 is a CCD
The field (FLD) signal 21 and the vertical drive (VD) signal 22 output from the controller 5 are used to activate FRM_OK from the start to the end of image capture.
Create signal 29. The AND circuit 11 and the horizontal clock (CL) signal 20 and the composite blanking (CBLK)
The logical sum of the pulse 19 and the FRM_OK signal 29 is taken.
Then, the AND circuit 11 outputs the WCK signal 30. The A / D converter 12 is a two-dimensional monochrome C of the image pickup unit 2.
Image input from CCD controller 5 of CD4 (V
(IDEO) signal 18 in synchronization with WCK signal 30 and A / D
Convert. The FIFO memory 13 stores the image data converted by the A / D converter 12 in synchronization with the WCK signal 30. The MPU 14 controls the entire image reading device. The decode circuit 15 accesses the peripheral device from the MPU 14. SCSI controller 1
Reference numeral 6 serves as an interface with the host computer 17.

FIG. 2 is a timing chart for explaining the operation of the image reading device. Here, using the signal obtained by taking the logical sum of the horizontal direction clock signal 20 output from the CCD controller 5 and the composite blanking pulse 19, the conversion of the A / D converter and the digitally converted image data are stored in the FIFO memory. The operation of writing data will be described.

The field (FLD) signal 21 and the vertical drive (VD) signal 22 are input to the FRM_OK signal generation circuit 10. STAR controlled by MPU14
When the T signal 28 becomes active, the field signal 21
The FRM_OK signal 29 becomes active during the period from the rising (time T1) to the rising (time T2) of the vertical drive signal 22. This FRM_OK signal 29
Are created by the FRM_OK signal creation circuit 10.

While the FRM_OK signal 29 is active, one image per color is captured. CC of this embodiment
The D controller 5 supports the CCIR system, and the horizontal drive signal HD is generated 625 times per image.
Further, the horizontal clock signal is generated 908 times per one horizontal drive signal HD. That is, two-dimensional monochrome CCD4
When storing all the angle of view in the FIFO memory 13, 5675 lines are 625 lines in the vertical direction and 908 dots in the horizontal direction.
A capacity of 00 bytes / 1 image is required.

Therefore, the AND circuit 11 causes the horizontal clock signal 20, the composite blanking pulse 19 and the FRM.
Taking the logical sum of the _OK signal 29, the WCK signal 30 (see FIG.
(J)) is created. Generally, the CCD controller 5 makes the composite blanking pulse 19 inactive while a predetermined number of HD signals are being output from the beginning of the first field. Similarly, the CCD controller 5 keeps the composite blanking pulse 19 inactive even while a predetermined number of HD signals are being output from the beginning of the second field. In the present embodiment, the composite blanking pulse 19 becomes inactive for 25 pulses of the horizontal drive signal HD from the beginning of the first field. Further, the composite blanking pulse 19 becomes inactive for 25 pulses of the horizontal drive signal HD from the beginning of the second field. Therefore, the WCK signal 30 is generated 741 times for each horizontal drive signal HD. Therefore, the storage capacity required for one image is 575 lines in the vertical direction × 74 in the horizontal direction.
One dot is 426075 dots / one image, and the memory capacity can be reduced by 141425 bytes compared with the case of saving the entire angle of view. As a result, the transfer amount to the host computer 17 is also reduced, and the transfer time can be shortened.

FIG. 3 shows a flow chart for explaining the operation of the MPU 14.

The program starts when the power switch is turned on. When starting, in step S1, a test of the power supply circuit system and initialization of parameters such as the number of dots in the horizontal direction and the number of dots in the vertical direction used when performing image capture are performed. ST in step S2
By turning on the B output 25, charging of the three colors of red, green and blue of the RGB strobe 6 is started. In step S3, S
It is detected whether the READY signal 26 becomes active within 10 seconds after turning on the TB output 25. If not activated, RG is performed in step S20.
Error processing is performed because the charging circuit section of the B strobe 6 is defective.

When it is detected in step S3 that the READY signal 26 has become active, the process waits until the capture start switch 8 is turned on in step S4.
After the acquisition start switch 8 is turned on, step S5
In, the emission color of the RGB strobe 6 is set. That is,
First COLOR signal 23 and second COLOR signal 24
To the red bit pattern. Then STAR
FRM_OK by activating T signal 28
Signal 29 becomes active.

In step S6, the rising of the FRM_OK signal 29 (time T1) is used as a trigger to cause the red RGB strobe 6 to emit light, and the FRM_OK signal 2
9. The image signal 18 is A / D converted in synchronization with the WCK signal 30 which is the logical sum of the CBLK signal 9, the CBLK signal 19 and the CL signal 20. In addition, the digitally converted signal is converted into the WCK signal 30
Is stored in the FIFO memory 13 in synchronism with, and the image data for one color is fetched.

In step S7, the interrupt signal by the FRM_OK signal 29 turns on the START signal 28.
It is detected that it falls within 100 ms.
In the present embodiment, the FRM_OK signal 29 is connected to the interrupt input terminal of the MPU 14, and setting is made so that an interrupt is generated when the FRM_OK signal 29 falls, and detection is performed. Here, if the interrupt does not occur within the time, it is determined in step S20 that there is a defect in the FRM_OK signal generating circuit 10 or its periphery, and error processing is performed.

After the interrupt by the FRM_OK signal 29 is generated, the START signal 28 is turned off in step S8, and the image data is transferred to the host computer 17 via the SCSI controller 16 in step S9. After the transfer is completed, steps S9 to S1
Up to 3, the green image is captured and transferred. Also,
In steps S15 to S19, the blue image is captured and transferred, and the data capture of one image is completed.

In the above embodiment, the AND circuit 1
1 is a horizontal clock (CL) signal 20, a composite blanking (CBLK) pulse 19, and an FRM_OK signal 29.
However, the same WCK signal 30 can be obtained by only taking the logical sum of the two signals of the horizontal direction clock (CL) signal and the composite blanking (CBLK) pulse 19.

The color separation of the image signal may be as follows. That is, filters having RGB colors are arranged in front of one Xe tube. When capturing an R image, the R filter is placed in front of the Xe tube to emit light from the Xe tube. To capture an image of another color, switch the filter color and
Light the tube. An electric motor may be used to switch the filters. In addition, the filter having each color of RGB is Xe
It may be arranged not in front of the tube but in the tube of the original 1 and the two-dimensional black and white CCD 4. Then, the image original can be color-separated in the same manner as described above.

[0026]

As described above, according to the image reading device of the present invention, the A / D conversion in the A / D conversion means and the storage device are performed by the OR signal of the horizontal clock signal and the composite blanking pulse. Since image signals are written, even if a two-dimensional CCD is used, one color
It is possible to reduce the capacity of the storage device per image and at the same time reduce the time required for transfer to the host computer.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing an embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a waveform diagram showing an embodiment of an image reading apparatus according to the present invention.

FIG. 3 is a flowchart showing an embodiment of an image reading device according to the present invention.

[Explanation of symbols]

 2 Image pickup unit 3 Optical system 4 Two-dimensional black and white CCD 5 CCD controller 6 RGB strobe 7 Strobe control unit 8 Capture start switch 9 Control unit 10 FRM_OK signal generation circuit 11 AND circuit 12 A / D converter 13 FIFO memory 14 MPU 15 Decoding circuit 16 SCSI controller 17 Host computer 18 Image (Video) signal 19 Composite blanking pulse 20 Horizontal direction clock signal 21 Field signal 22 Vertical drive signal 25 STB output 26 READY signal 28 START signal 29 FRM_OK signal 30 WCK signal

Claims (5)

[Claims] 1. An illumination unit for illuminating a document, a photoelectric conversion unit for two-dimensionally reading a document image illuminated by the illumination unit, and outputting an analog image signal according to the read brightness, the analog image signal. A / D conversion means for A / D converting and outputting a digital image signal; photoelectric conversion means control means for controlling the photoelectric conversion means and outputting a horizontal direction clock signal and a composite blanking signal; An image reading apparatus comprising: AND means for taking a logical sum of a clock signal and the composite blanking signal; and a storage device for storing the digital image signal in synchronization with an output signal of the AND means. 2. A color separation unit for separating the color of the image of the original document into a plurality of different colors by using the illumination light of the illumination unit, and the original image separated by the color separation unit. The image reading apparatus according to claim 1, wherein the photoelectric conversion unit reads the image. 3. The image reading apparatus according to claim 2, wherein the color separation means has a filter corresponding to the plurality of different colors. 4. The image reading apparatus according to claim 2, wherein the color separation unit separates the color of the light emitted from the illumination unit into a plurality of different colors before the arrival of the original. 5. The image reading apparatus according to claim 2, wherein the color separation unit sequentially separates the colors of the light incident on the photoelectric conversion unit into a plurality of different colors.