JPH01123567A - Picture reader - Google Patents

Abstract

PURPOSE:To execute an appropriate corresponding treatment according to the purpose, the function, etc., of a host device, etc., by reading and storing the density of an original, detecting the white paper of the original with the original density data, and informing of the white paper. CONSTITUTION:The title device is equipped with an original density reading means to read the density of the original with an image pickup element, a storing means to store the read original density data, a white paper detecting means to detect the white paper of the original with the stored original density data, and an informing means to inform of the detected result of the white paper detecting means. Namely, when the white paper of the original is detected by the white paper detecting means, the detected result is informed to the external equipment of the host device, etc., which is connected to a picture reader, with the informing means. Thus, the appropriate corresponding treatment according to the purpose, the function, etc., of the host device, etc., can be adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device that reads characters, figures, etc. of a document using an image sensor.

``Conventional technology'' Images such as images and documents are created using electricity (digital technology).
Storage and transmission by converting into signals.

Information processing becomes easier. For this reason, an image reader using an image sensor is used as the image reading device that is the image input means. Image League divides an image of a document or the like into a fine mesh, converts the image portion into black and the non-image portion into white, and outputs it as a digital signal to an external device. Therefore, even if the document is blank with nothing displayed on it, a binary digital signal is output.

``Problems to be solved by the invention'' However, in document processing systems, filing systems, etc., when reading a manuscript using an image league and sequentially storing the read data in a storage means such as an optical disk, it is difficult to If a blank page is included, the image league will output blank data as described above and record the data on the optical disk, which will be uneconomical in terms of storage capacity.

In addition, when reading facsimile transmission data, sending blank data as is will result in outputting blank data to the receiving side and cause uneconomical effects such as wasted line usage, which cannot be resolved. This was a problem that should be addressed.

"Specific Means for Solving" The present invention aims to solve the above-mentioned problems. an original density reading means for reading the original density data with an image sensor; a storage means for storing the read original density data; a blank paper detection means for detecting a blank page of the original based on the stored original density data; and a detection result of the blank paper detection means is notified. The present invention is characterized by comprising a notification means.

"Operation" As clarified by the explanation of the above-mentioned specific means, in the present invention, when a blank page of a document is detected by the blank page detection means,
The detection result is notified to an external device such as a host device connected to the image reading device by the notification means.

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

FIG. 1 shows a schematic structure of the image reading device 1. As shown in FIG.

Reference numeral 2 denotes an original table glass for affing the original, and a document cover 3 that can be freely opened and closed blocks external light. Original table glass 2
The document placed on the document is irradiated with lamp light from a halogen lamp 4, which is focused by a reflecting mirror 5 with a substantially U-shaped cross section, and the reflected light is directed to a lens 9 via a scanning mirror 6.7°8. The light is guided and an image is formed on a photoelectric conversion element (hereinafter referred to as COD) 10.

The halogen lamp 41 reflecting mirror5. Scanning mirror 6.7.
Reference numeral 8 denotes a scanning system S that integrally moves in the sub-scanning direction (arrow in FIG. 1) to read the entire document. In this case, the moving length of the scanning mirror 6 and the scanning mirror 7.8 is set to 2=1, and the optical path length is kept constant.In the main scanning direction perpendicular to the sub-scanning direction, an image is obtained by electrical scanning of the CCD 10. The CCD 10 is held on the CCDCD holder, and its position and angle are adjusted.

The CCDCD holding unit upper lens 9 is attached to a moving table 12. Adjustment of the magnification is performed by moving the moving table 12 in the optical axis direction by a moving mechanism (not shown), and focus adjustment is performed by turning on the focus motor 13. At the time, the image is printed on the back side of the wXX scale 14 fixed to the edge of the original table glass 2. Read the focus adjustment pattern with C0D10, store the data in line RAM to be described later, and C)
) U analyzes the data and traces the C0 to the correct focal position.
Rotate the focus motor 13 so that D10 is positioned.

The document scale 14 indicates the document position on the document platen glass 2, and also indicates the position of the document on the document table glass 2, and also indicates the position of the document on the document table glass 2.
A magnification detection pattern and a shading correction pattern are printed and read as necessary.

FIG. 2 is a block diagram of the image reading device 1. As shown in FIG.

The clock generator 23 generates S necessary for the CCD 10.
H (Sa+*pl 1old) signal is given, and on the other hand, it is connected to the CPU 21 and used as a clock signal.
The C0DIO converts image data (amount of light) into voltage according to a clock signal from the clock generator 23 and outputs the voltage. The output voltage of C0DIO is converted by the A/D converter 24 into a digital value that allows the CPU 21 to recognize the received light data, and then enters the shading corrector 25. The shading correction unit 25 corrects uneven light amount in the main scanning direction and the CCD 10.
This is for electrically correcting variations in sensitivity between each bit of , and shading data for correction is provided from the CPU 21 . This shading data is calculated by the CPU 21 by reading a shading correction pattern printed on the back side of the document scale 14. The output from the shading correction section 25 is input to the comparison section 27 and line RAM 26. The comparison unit 27 compares the data corrected by the shading correction unit 25 and the binarization threshold input to the comparison unit 27, and converts the result into (0
) or (1) (1 bit). That is, the read data is converted into binary data (white), power, black), and is input to the output section 28. The output unit 28 outputs the binary data and the valid image signal from the CPU 21 to the outside. The line RAM 26 stores shading-corrected data for one scan in the main scanning direction. line RAM2
Writing/reading of data to/from the CPU 21 is performed by the R
/W signal. When the CPU 21 reads the data written to the line RAM 26, the CCD 1
Changes in the amount of light received at 0 can be detected.

In addition, the CPU 21 has command signal input/output terminals for receiving command signals such as scan commands and mode changes from the host device and transmitting them to the host device, and signals for driving the lens motor, focus motor, and scan motor. An output terminal, a motor signal input terminal for inputting the motor rotation speed, a fixed position signal input terminal for receiving the output of a sensor that detects the position of the scanning system S that integrates a lamp, a reflector, and a scanning mirror, and a 0N10FF terminal for the lamp. It has a lamp signal output terminal for controlling, a valid image signal output terminal for controlling output of read image data, and the like.

Next, the image reading operation and the blank document detection operation will be explained according to the attached flowcharts.

FIG. 3 is a flowchart 1 showing the main routine of this embodiment.

(Step 330) (Steps will be omitted below) After turning on the power, the bin!・Initialize the conditions necessary for operation such as adjustment and magnification adjustment, and then change the mode and execute image reading (S32) to (S34) depending on the type of command manually input from the post device in (S31). . When there is no command input, the command waits.

FIG. 4 is a flowchart showing an execution routine for mode change (FIG. 3 (S32)).

It is determined whether the mode commanded by the host device (e.g., reading size λ, reading magnification 1M light level, etc.) is valid, and if it is valid (YES in S40), the settings associated with changing the mode are determined. (For example, changing the magnification by moving the lens) and updating the mode (S41).

5th ri1 (a), (b) C, picture 1'AVtR')
7 is a flowchart showing a blank document detection operation (briscan) during routine execution.

The image reading operation begins in response to a command from the host device. First, after lighting the lamp (850), it is determined whether the scanning system S is in the normal position, and if so (YES in S52>(
Jump to S56). If not, the motor is rotated in the return direction to return to the home position, and when it returns to the home position, the motor is turned off (853) to (S55).In (356), the scanning system S is moved from the home position in the sub-scanning direction. , starts prescanning to detect blank originals. When the scanning system S crosses the shading correction pattern printed on the back side of the document scale 14, the CPU 21 stores the shading data in the line RAM 26 and calculates the shading correction data (S57). Since this is a pre-scan, the valid image signal is turned off (858) and output of image data is prohibited. <559), a counter (BTOTAL) counts the number of pixels determined to be black on the entire surface of the document.
Clear and set the counter value to O. Next (S60)
When it is determined that the scanning system S has reached the leading edge of the document, the CP
U21 writes the image data read by the CCD 10 to the persistent line RAM 26 (361), checks the presence or absence of a black level signal in the image data, counts the number of pixels that are black, and stores the value in the counter (361). BTOT A
L) (S62).

Determination of the presence or absence of a black level signal in image data will be described in detail later.

Next, in (363) it is determined whether or not the scan has finished, and if it has not finished, the above (S61) and (S62) are repeated, and if it is finished (YES in 863), the lamp is turned off and the motor is turned off. is rotated in the return direction to return the scanning system S to its home position, and the motor is turned off to complete the bliscan (S64) to (S67).

In (S68), the value of the counter (BTOTAL) counted when the read image data is determined to be black is compared with the threshold value of the number of black pixels (B C0UNT) that is determined to be a blank document, and if BTOTAL<BCOUNT, CPU if available
21 determines that it is a blank document and sends a detection command to the host device (S70).

Upon receiving the blank document composition command, the host device performs a predetermined process, for example, forcibly ejects the blank document using the automatic document feeder, displays an alarm, displays on the CR7 screen, etc., and notifies the operator of this fact. Also (S68) BTOTA
When it is determined that L>BCOUNT, the presence of characters or the like in the document is detected, and the image reading processing (main scan) routine is called (S71).

FIG. 6 is a flowchart showing the image reading processing (main scan) routine.

After turning on the lamp in (S80), (S81) to (
In step S84), it is confirmed that the scanning system S is in the normal position, and the scanning system S is moved from the normal position in the sub-scanning direction to start scanning (585). Subsequently, in (S86), shading data is written in the line RAM in the same manner as in the case of bliscan, and shading correction data is calculated (S86). When the scanning system S reaches the leading edge of the document (S
When the scanning system S reaches the trailing edge of the document (YES at S89), the effective image signal is turned on to output the read image data to an external device (588). At the same time, the lamp is turned off, the scanning system S is returned to the normal position, and the motor is turned off (S90).
91) to (S94), the document reading operation is thus completed.

Next, determination of the presence or absence of a black level signal in document data will be explained.

When the CPU 21 reads one line (one main scan) of data, the image data of each read pixel is expressed in 2° steps from the white level to the black level (n is the number of bits of the digital value). For example, when n=8, the data value is divided into 256 levels from OOH to FFH (hexadecimal notation).

When the image data of each read pixel is distributed in every 2'=256 stages, the graph shown in FIG. 7 is obtained. Here, the total number of detections matches the total number of read pixels. Here, a certain determination level (for example, 80H) is set, and pixels of image data values distributed to the right side of this level are determined to be black level, those distributed to the left side are determined to be white level, and the number of pixels of black level is determined by a counter (BTOTAL). ) to count.

The BTOTAL counter value after the prescan is the number of pixels determined to be the black level in the read document. By comparing this value with a preset value (BCOUNT value), blank originals can be detected as described above. Here, as described above, the B COU N 'I' value is the threshold value of the number of black pixels for determining a blank document.

Figures 8(a) and 8(b) show the output of the comparison unit with respect to the output value of the shading correction unit and the result of determining the number of black pixels. , the blank original judgment level is set to COH, and in the same figure (b), the binarization threshold is set to 80H, and the blank original judgment level is set to 1)O.
It is set as H.

According to (a) of the same figure, the shading correction unit output value is
The number of pixels determined to be black by the blank document determination level inside the CPU is 6 out of 21 pixels, and the comparison section output is 2.
The number of pixels output as black (1) by comparison with the valuation threshold is 10 out of 21 pixels. In this way, the binarization threshold input to the comparison section and the blank document determination level can be made different, and the effect of making them different is shown in the figure (
b) will be explained in more detail. In this case, it is assumed that a document with unclear black-and-white contrast and an overall whitish appearance is to be read, and specifically, a document with pencil writing or the like is to be read. Therefore, the output of the shading correction section tends to be biased toward 0OH (white) as a whole. According to the figure, 4 out of 21 pixels output data as "black" to the outside in the comparison section, but the blank document determination level is set lower than the binarization level, and the black of the pencil drawing and the document are The level where the difference with the base is sufficiently compared (for example, 6
0H), the number of pixels judged to be black by the CPU is 15 out of 21, with many areas written in pencil being detected.
Becomes a pixel. This is continued sequentially over the entire document, and when the BTOTAL value, which is the number of pixels determined to be black, becomes greater than the BCOUNT value, the image reading device
It is determined that images such as characters are present in the document through processing, but the data that the image reading device outputs from the output unit to the external device during the main scan has a high white level as described above, and the characters etc. are not faded. Become something. Therefore, when a blurred or white missing character occurs in this way, it is possible to determine whether or not to perform the reading again based on the results of both determinations. When performing reading again, clearer image data can be output by lowering the level of the binarization threshold.

Furthermore, the number of black pixels BTO determined at the blank document determination level
If the difference between the TAL value and the total number of black pixels output by the comparing section is large, it can be determined that a reading error has occurred.

As described above, by changing the blank document determination level according to the state of the document, it is possible to reliably prevent blank document detection errors due to noise such as dust.

Furthermore, if an ADF (automatic document feeder) is installed in place of the document cover 3 described above, even after the ADF has started operating, if the document is determined to be blank, the document will be automatically moved. Alternatively, the copying operation may be controlled so that the copying operation is not started.

"Effects" As clarified by the description of the specific means and effects, the present invention comprises a document density reading means for reading the density of the document by an image sensor, a storage means for storing the read document density data, and a memory device for storing the read document density data. blank page detection means for detecting a blank page of a document based on original density data, and notification means for notifying a detection result of the blank page detection means; Since the notification is sent to an external device such as a host device connected to the image reading device, appropriate countermeasures can be taken according to the purpose 1 function of the host device etc.

[Brief explanation of the drawing]

The accompanying drawings show an embodiment of the present invention, in which FIG. 1 is a schematic sectional view of an image reading device, FIG. 2 is a block diagram thereof, FIG. 3 is a flowchart showing the main routine, and FIG. 4 is a mode change diagram. Flowchart showing the routine, FIG. 5(a),
(b) is a flowchart showing the image reading (prescan) routine, FIG. 6 is a flowchart showing the image reading (main scan) routine, FIG. Figure”(a>
, (b) are explanatory diagrams showing the output of the comparison unit and the black pixel number determination result with respect to the output value of the shading correction unit. 1191 image reading device, 10. ,,CCD, 21°,,CPU, 25. ,,shading correction section, 2
6., line RAM, 27. ,,Comparison section, 28
゜0. Output section. Figure 1 Figure 4 Figure 7 (OOH) (80H) (FFI-1) 2
56 steps P

Claims (1)

[Claims] A document density reading device that reads the density of the document using an image sensor, a storage device that stores the read document density data, a blank page detecting device that detects a blank page of the document based on the stored document density data, and a detection result of the blank page detecting device. An image reading device comprising a notification means for notifying.