JP2000270159A - Method of controlling image reader and recording medium thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a normal white reference even if dust entering an image reader sticks on a white reference area by comparing the mean output value of individual read pixels obtained by reading the white reference area with the mean value of all output values obtained by reading the individual read pixels. SOLUTION: The white reference area is read by blocks obtained by dividing the white reference areas in a vertical scanning direction, the mean output values of individual read pixels are calculated by the blocks and compared with one another, and if a block having a decrease output place is found, the block is specified as a dust detected block whose output has decreased owing to dust sticking on the white reference area; and the block is excluded to remove the influence of the dust sticking on an optical path in the device and the block having the largest mean value is selected out of the remaining blocks to obtain the white reference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for controlling an image reading apparatus, the method comprising detecting dust adhering to an optical path of the image reading apparatus, and generating a white reference excluding the influence of the dust. Control method,
The present invention relates to a computer-readable recording medium storing the above control method.

[0002]

2. Description of the Related Art Here, the definitions applied to the following terms according to the present invention will be described to clarify the concepts included therein.

[0003] The white reference is a white reference value prepared by the image reading apparatus when reading an original. A white reference area having a uniform white density distribution is read prior to reading of the original, and the output level is read. The stored output signal is corrected using the output level as a reference value. By having the above-described white reference, it is possible to correct shading, which is uneven reading output caused by, for example, non-uniformity of the sensitivity of the reading sensor.

[0004] The white reference area is a reference plate having a uniform density distribution of white color provided in an image reading apparatus to obtain the above-mentioned white reference.

[0005] Here, dust refers to fine particles and the like, which are foreign substances that have entered the image reading apparatus and adhered to the optical path in the apparatus. Naturally, if there is a foreign matter in the optical path in the image reading device, the image signal obtained by reading the document by the image reading device will be mixed with the signal obtained by reading the foreign material, thereby damaging the original image signal. become. Therefore, measures are usually taken to prevent the intrusion of foreign substances by providing a dust-proof function to the structure of the image reading device, and to perform careful cleaning to remove such foreign substances. Fine particles and the like which are difficult to detect are difficult to remove and may remain as they are. Here, as described above, the target is dust due to fine particles or the like which are difficult to detect by visual observation.

The dust is classified into dust adhering to the white reference area and dust adhering to a portion in the optical path other than the white reference area.

The dust adhering to the former white reference area forms a clear image because it is present on the surface to be read by the reading sensor of the image reading device. Further, the read output obtained by reading the dust directly affects the formation of the white reference, and lowers the reference value. Therefore, in the subsequent operation, the image output obtained by reading the original with reference to the white reference formed by reading the dust described above has no dust in the original, so that the signal value of the portion corresponding to the dust is the actual original. It is recognized as a brighter image.

The dust adhering to a portion in the optical path other than the white reference region exists on an optical path other than the reading target surface read by the reading sensor of the image reading device like dust adhering to a mirror, for example. A clear image is not formed. Further, the read output obtained by reading the dust directly affects the formation of the white reference,
Although the reference value is reduced, the same image is always read in the subsequent operations. Therefore, even if a document without dust is read, the signal value of the portion corresponding to the dust is recognized as an image brighter than the actual document. There is nothing.

Therefore, the dust attached to the former white reference area should have its output reduced portion removed when forming the white reference, and the dust attached to a portion in the optical path other than the latter white reference area should be formed. In this case, the output reduction portion must be left.

Referring to FIGS. 23 to 28, a description will be given of a method of controlling an image reading apparatus implemented based on the conventional technique.

The reading of the white reference area will be described with reference to FIG. That is, as shown in FIG.
Numeral 3 reads the white reference area 51 and presents a read output waveform shown in FIG. Further, the waveform of the read output indicates individual read outputs according to the characteristics of the individual read pixels constituting the scanning line 53 as shown in the enlarged view.

Referring to FIG. 24, reading of a white reference area having dust will be described. That is, as shown in FIG. 24A, the scanning line 53 reads the white reference region 51, but when the scanning line 53 reads a portion different from the portion where the dust 52 exists, the scanning line 53 is flat as shown in FIG. When the scanning line 53 reads a portion where the dust 52 is present, as shown in FIG. 24 (c), the output is performed only at a portion corresponding to the read pixel position 54 where the dust 52 is read. The value drops significantly.

For example, in the case where dust adhering to the mirror is read, as shown in FIG. 24 (d), the reading output decreases at a level smaller than the output drop due to the dust adhering to the white reference area. However, when the dust adhering to the mirror is read, a decrease in output occurs regardless of the position of the scanning line.

Referring to FIG. 25, a white reference area having dust is read, and the output reduction due to the dust is recovered.
An example of a method for controlling an image reading apparatus based on a conventional technique for generating a white reference excluding the influence of dust will be described.

That is, the control method shown in FIG.
This is a control method for forming a white reference by using the maximum value of each read output of each read pixel read by different scanning lines.

As an example shown here, an example is shown in which the read output of each read pixel is displayed at that ratio and read by five scanning lines. Further, an example is shown in which dust is present at a mirror position corresponding to the pixel P and dust is present in a white reference area corresponding to the pixel Q.

Looking at the read output values of the pixels P, the read output values for the scanning line are 78 and 8 respectively.
Output values of almost the same level as 0, 79, 78, and 79 are shown, and the maximum value, 80, is taken as a representative value, and is set as an output value constituting a white standard. This indicates that the output value due to dust adhering to the mirror was reflected on the white reference.

Looking at the read output values of the pixel Q, the read output values for the scan line are 97, 1
2, 18, 99, and 98, and the read output of the second scan line and the third scan line is greatly reduced. Here, as in the case of the pixel P, the read output is also a representative value. The maximum value of 99 is taken as an output value constituting the white reference. By this measure, it is understood that the white reference is formed by excluding the output value of the portion where the read output is reduced due to the dust attached to the white reference area.

However, looking at the read output value of the pixel R, each read output value for that scan line is 9
7, 96, 97, 100, and 97, which indicate output values protruding on the fourth scanning line.

The above-mentioned prominent output value is generated when the reading light is intensified due to a gloss abnormality or the like caused by a defect in the white reference area, and the above-mentioned prominent output value is employed as a representative value as it is. Then, the generated white reference has a configuration including the above-mentioned prominent output value.

When image data obtained by reading an original is generated by using the white reference including the protruding output value, image data having a lower brightness than the other pixels is generated at the pixel reading the protruding output value. I do.

Referring to FIG. 26, FIG. 27 and FIG. 28, a description will be given of a flow of generating a white reference of an image reading apparatus implemented based on the conventional technique.

FIG. 26 is a block diagram showing the configuration. That is, the image reading device B01a has a white reference area B12, and a reading unit B13 having a reading pixel B14 for reading the white reference area B12 is moved by the unit moving unit B15 to set the position of the scanning line.

The read output value read by the read pixel B14 is converted to a white reference by the arithmetic control unit B10 and stored in the white reference unit B11, and is used as a reference value for generating image data in the subsequent document reading. Is done.

Further, the image data generated by the image reading device B01a is transferred to the driver program B21 of the host device B02, and the arithmetic control unit B20 performs a predetermined process.

FIG. 27 is a flowchart showing the flow of white reference generation performed by the image reading apparatus based on normal control.

In step S501, the image reading device B01a that has received the reading instruction from the host device B02.
Proceeds to step S502 to read unit B13
Reads the white reference area B12.

In step S503, a white reference is constructed based on the read output values output from the individual read pixels B14, and stored in the white reference section B11.

In step S504, the reading unit B1
3, the process proceeds to step S505, where the arithmetic and control unit B10 generates image data based on the white reference stored in the white reference unit B11, and proceeds to step S506 to transfer the image data to the host device.

FIG. 28 is a flowchart showing a flow of white reference generation performed by the image reading apparatus based on the control shown in FIG.

In step S511, the image reading device B01a that has received the reading instruction from the host device B02.
Proceeds to step S512, and proceeds to reading unit B13.
Reads a white reference area B12 in a specific scanning line.

In step S513, the above-described step S5
At 12, the read output values read by the individual pixels B14 are temporarily stored.

In step S514, the unit moving section B15
Moves the reading unit B13, and proceeds to step S515.
Then, the reading unit B13 reads the white reference area in the newly set scanning line.

In step S516, the arithmetic and control unit B10 designates an output value of a specific pixel from the read output value read in step S515, and proceeds to step S517.
Then, the read output value of the specific pixel is compared with the read output value of the same pixel corresponding to the read output value temporarily stored earlier.

In step S518, the above-described step S51 is performed.
If the read output value read in step 5 is larger than the stored value, the flow advances to step S519 to rewrite the stored value to the read output value read in step S515.

If it is determined in step S518 that the read output value read in step S515 is equal to or smaller than the stored value, the flow advances to step S520 to read the read output value read in step S515. Is discarded, and the stored value is left as it is without rewriting.

If the succeeding pixel remains in step S521, the flow returns to step S516 to specify the succeeding pixel. If all the pixels to be compared and checked have been completed, the process proceeds to step S522 to check whether the predetermined number of readings has been completed. If the reading scanning has not been completed, the process returns to step S514, and if the reading scanning has been completed. Proceeds to step S523, determines the white reference with the saved value, and stores it in the white reference section B11.

In step S524, the reading unit B1
3 reads the original, proceeds to step S525, and the arithmetic and control unit B10 generates image data based on the white reference stored in the white reference unit B11, and proceeds to step S526 to transfer the image data to the host device.

[0039]

As described above, the conventional method of controlling an image reading apparatus has the following problems in generating a white reference.

If dust entering the image reading apparatus adheres to the white reference area, there is a risk that the dust is read in the process of generating the white reference.

When an original is read using the white reference from which the dust is read, the image data of the pixel from which the dust is read in the image data is brighter than other pixels to generate image data. Therefore, the image data is damaged.

As a method of generating a white reference without reading dust adhering to the white reference area, there is known a method of forming a white reference with a maximum output value read by each pixel with a plurality of scanning lines. I have.

However, in the above-described method of forming the white reference using the maximum output value read by each pixel, an abnormal output generated when the reading light becomes strong due to an abnormal gloss caused by a defect in the white reference area or the like. There is a risk of taking the value as the maximum output value.

When a document is read using the white reference in which the abnormal output value is taken as the maximum output value, the image data of the pixel from which the dust is read out of the image data is darker than the other pixels. Generate Therefore, the gradation of the image data is impaired.

The problem to be solved by the present invention is that even when dust entering the image reading apparatus adheres to the white reference area, the white reference is formed without reading the dust in the process of generating the white reference. At the same time, a normal white reference is generated by relaxing an abnormal output value generated when the reading light becomes strong due to a gloss abnormality or the like generated due to a defect in the white reference region.

[0046]

In order to solve the above problems, the present invention employs the following means.

1) When generating the white reference, the average value of the read output is calculated for each pixel read from a specific area of the white reference area.

By taking this measure, the average value of the read output of the pixels that read the dust adhering to the white reference area is reduced by the averaging, and at the same time, the output reduction amount due to the dust is reduced. In the average value of the read output of the pixels obtained by reading the dust adhering to the optical path, the output reduction amount due to the dust is not changed by the averaging, and the output reduction amount is maintained.

Further, by taking this means, the pixel which outputs a protruding read output value when the reading light becomes intensified due to the gloss abnormality of the white reference area or the like is reduced by averaging. Also get.

2) The procedure for calculating the average value is stored in a computer-readable recording medium as a part of a control program for controlling the image reading apparatus.

By this means, when the image reading apparatus generates the white reference, it has an effect of providing a procedure for calculating the average value of the read output at each pixel reading a specific area of the white reference area. .

3) When the white reference is generated, the white reference area is divided into a plurality of blocks and read, and the average value of the read output is calculated for each pixel in each block that has read the area.

By taking this measure, the average value of the read output values of the pixels located at the position corresponding to the dust adhering to the white reference area becomes the read output value at which the dust is not read in blocks other than the block where the dust is located. Indicates the average value, and at the same time, in the average value of the read output of the pixels that read the dust adhering to the optical path other than the white reference area such as a mirror, the output reduction amount due to the dust does not change even in the averaging, and is the same for all blocks The effect of keeping the output reduction amount is obtained.

4) The procedure of dividing the white reference area into blocks and calculating the average value of the read output at each pixel read by the divided blocks is performed by a control program for controlling the image reading apparatus. Partly stored in a computer-readable recording medium.

By this means, the image reading apparatus is provided with a procedure for calculating the average value of the read output at each pixel which has read an area divided into blocks of the white reference area when generating the white reference. Get.

5) In the image reading apparatus, standard data obtained by reading the white reference area in advance at the time of adjustment shipment is recorded as teacher data, and when generating the white reference, reading is performed on individual pixels that read a specific area of the white reference area. The average value of the output is calculated and compared with the teacher data.

By adopting this means, the image reading apparatus has an effect of detecting a decrease in the read output indicated by the pixel that has read the dust adhering to the white reference area by comparing and collating with the teacher data.

6) The procedure for calculating the average value and the teacher data to be compared with the average value are stored in a computer-readable recording medium as a part of a control program for controlling the image reading apparatus. I do.

By this means, when generating the white reference, the image reading apparatus is provided with a procedure for calculating the average value of the read output for each pixel read from the white reference area and comparing with the teacher data. Get action.

[0060]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention takes the following forms.

1) In the control method of the image reading apparatus, the average output value of the individual read pixels which read the white reference area is calculated, and the average output value of the individual read pixels and the individual read pixels are read. By comparing and comparing the average value of all the output values, the presence of dust attached to the optical path in the apparatus is detected.

2) In the control method of the image reading apparatus, the dust whose presence is detected is observed by observing the level of decrease in the average output value of the individual read pixels that have read the white reference area. It is determined whether the dust is attached to the optical path other than the white reference area.

By adopting these forms, the image reading apparatus can remove the element reading the dust adhering to the white reference area from the output reduction portion included in the read output value of the individual read pixel reading the white reference area. The effect of determining is obtained.

3) In the control method of the image reading apparatus, the average output value of the individual read pixels which read the white reference area is calculated, and the average output value of the individual read pixels constitutes the white reference.

By taking this form, the image reading apparatus has an effect of generating only a white reference and attenuating only an output reduction amount caused by reading of dust adhered to the white reference area by each read pixel. .

4) In the control method of the image reading apparatus, the white reference area is divided into a plurality of blocks divided in the sub-scanning direction, and the white reference area is read in units of the blocks. By calculating the average output value of the read pixels and comparing and comparing the average output values of the individual read pixels calculated for each of the individual blocks, a white standard that eliminates the influence of dust attached to the optical path in the apparatus is obtained. Constitute.

5) In the control method of the image reading apparatus, the white reference is constituted by the maximum value of the average output value of the individual read pixels calculated for each block.

6) In the control method of the image reading apparatus, the average output value of the individual read pixel calculated for each block is compared and compared between the blocks, and the block having the lowered output portion is identified. The block is identified as a dust detection block, and the remaining blocks excluding the dust detection block constitute a white reference.

7) In the control method of the image reading apparatus, a block having the largest average value is selected from the remaining blocks excluding the dust detection block, and is set as a white reference.

8) Alternatively, in the method of controlling the image reading apparatus, a block whose average value is an intermediate value is selected from the remaining blocks excluding the dust detection block, and is used as a white reference.

9) Alternatively, in the control method of the image reading apparatus, an average value of each of the read pixels is calculated from the remaining blocks excluding the dust detection block to form a white reference.

10) Alternatively, in the control method of the image reading apparatus, in the average output value of the individual read pixels calculated for each block, the output drop portion which is detected equally in all the blocks is white. It is determined that dust has adhered to the optical path other than the reference area, and a white reference is formed by including the above-mentioned output reduction portion.

By adopting these forms, the image reading apparatus can divide the white reference area into blocks and avoid the block in which dust is read from the average value of the read output values of the individual read pixels read by dividing the white reference area into blocks. Is obtained.

11) In the control method of the image reading apparatus, the average output value of the individual read pixels which read the white reference area is calculated, and the average output value of the individual read pixels is compared with the teacher data provided in advance. By collation, the presence of dust attached to the optical path in the device is detected

12) In the control method of the image reading apparatus described above, the level of reduction in the average output value of the individual read pixels that have read the white reference area is compared with the teacher data to detect dust that has detected the presence. It is determined whether dust adhered to the white reference area or dust attached to the optical path other than the white reference area, and it is determined that the detected dust is dust attached to the white reference area. In this case, the average output value is corrected based on the teacher data to form a white reference.

13) In the control method of the image reading apparatus described above, the level of reduction in the average output value of the individual read pixels that have read the white reference area is compared with the teacher data to detect dust that has detected the presence. It is determined whether the dust attached to the white reference area or the dust attached to the optical path other than the white reference area, and the detected dust is the dust attached to the optical path other than the white reference area. If it is determined that there is, the teacher data is corrected and updated without correcting the average output value, thereby forming a white reference.

By adopting these modes, the image reading apparatus has an effect of correcting the read output obtained by reading the white reference area based on the teacher data to generate the white reference.

14) A procedure in which the image reading device calculates the average output value of the individual read pixels that have read the white reference area, the average output value of the individual read pixels, and the read of the individual read pixels. And a procedure for comparing and comparing the average value of all the output values with the average value of the output values is stored in a computer-readable recording medium.

15) Alternatively, the image reading device may divide the white reference area into a plurality of blocks divided in the sub-scanning direction, and may sequentially read the plurality of divided blocks, By comparing the average output value of the individual read pixels with the average output value of the individual read pixels calculated for each individual block, the influence of dust attached to the optical path in the apparatus is reduced. A control program for executing the procedure for configuring the excluded white reference is stored in a computer-readable recording medium.

16) Alternatively, a procedure for calculating the average output value of the individual read pixels that have read the white reference area, a procedure for extracting the teacher data provided in advance, and a procedure for calculating the average output value of the individual read pixels and the teacher data Is stored in a computer-readable recording medium to execute the procedure of detecting the presence of dust adhering to the optical path in the apparatus by comparing and checking the above, and forming a white reference excluding the influence of the dust. .

By adopting these forms, the image reading apparatus has an effect of providing a procedure for generating a white reference while avoiding a reduced output portion where dust is read from a read output obtained by reading the white reference region.

[0082]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment according to the present invention will be described with reference to FIGS.

One representative embodiment of the present invention will be described with reference to FIGS. 1, 2 and 5. FIG. 1 shows the principle of an embodiment of the present invention.

As shown in FIG. 1A, when dust 2 adheres to the white reference area 1 and when the scanning line 3 is located in a portion where the dust 2 does not exist, the read output is as shown in FIG. )
As shown in the figure, the output of each read pixel shows a substantially flat output state. Obviously, if the output is microscopically observed, the output shows a variation according to the characteristics of the individual read pixels as already described with reference to the enlarged view of FIG.

When the scanning line 3 coincides with the position where the dust 2 adheres, the reading output greatly decreases at the reading pixel position 4 corresponding to the dust 2 as shown in FIG. .

Further, the scanning line 3 corresponds to the white reference area 1
If the average value of the read output values output by the individual read pixels is calculated by sequentially reading the predetermined areas of the above, the reading of the portion corresponding to the read pixel position 4 where the dust is detected as shown in FIG. The decrease in output is alleviated.

Referring to FIG. 2, the principle of discriminating dust adhering to the white reference area and dust adhering to other than the white reference area such as a mirror from the average value of the read output values read by the individual read pixels will be described. I do.

In the following description, dust adhering to areas other than the white reference area such as a mirror is referred to as dust adhering to the mirror.

As already described with reference to FIG.
When the read pixel reads dust adhering to the white reference area, the read output value output from the read pixel greatly decreases. This is because in the white reference area where the dust is located, the read pixels are in focus and a clear read output is obtained.

However, as described above, the read output value greatly decreases only in the portion where dust is actually read, and since it is a transient value, the scanning line scans a predetermined area of the white reference area. When the average value of the read output values is calculated, the average value is shown as a small decrease amount as shown in FIG.

When the read pixels read the dust adhering to the mirror, unlike the dust adhering to the white reference area, the focus is not sufficiently focused, so that the image adheres to the white reference area due to blurring of the image. There is less decrease in read output value than dust.

At the same time, the dust adhering to the mirror is always a target for reading even if the target position of the reading is moved, so that the scanning line reads a predetermined area of the white reference area and the read output value of the white reference area is read. Even when the average value is calculated, the output decrease amount does not change as shown in FIG.

Therefore, by calculating the average value of the output values of the individual read pixels that have read the white reference area,
By fixing the output reduction amount obtained by reading the dust attached to the mirror, only the output reduction amount obtained by reading the dust attached to the white reference area can be reduced.

According to the principle described above, the number of scanning lines for reading the white reference area is set to a predetermined number, and the average value of the output values of the individual read pixels read out is calculated to thereby attach the scanning lines to the white reference area. It is possible to attenuate only the output reduction amount obtained by reading the collected dust to a level that does not hinder the image data in practical use.

This means that, for example, in image processing for reading an image with binary data, a white reference region of a predetermined appropriate region is read, and the average of the read output values of the individual pixels that read the white reference region is calculated. The calculation suggests that it is possible to generate a white reference in consideration of the influence of dust adhering to the mirror while eliminating the influence of dust adhering to the white reference area.

FIG. 5 shows an example of the read output value of each pixel obtained by reading dust on each scan line. FIG. 5A shows a case where dust adhering to the white reference area is read. That is, although the read output value of the pixel from which the dust adhered to the white reference area has been read is greatly reduced, if the average output value is calculated for each pixel, the place where the dust is located may be transient. If the value is
As the parameter for calculating the average value increases, the decrease amount decreases.

Similarly to the case of the above-mentioned dust reading, even when a gloss abnormality occurs in the white reference area and temporarily shows a high reflectance, the location of the gloss abnormality is a transient value. If so, the larger the parameter for calculating the average value, the smaller the amount of influence.

FIG. 5B shows a case where dust adhering to the mirror is read. That is, although the read output value of the pixel that has read the dust adhering to the mirror is lower than that of the dust adhering to the white reference area, the output always decreases in all the scanning lines. Therefore, even if the parameter for calculating the average value increases, the influence amount does not change.

Referring to FIG. 3 and FIGS. 6 to 11,
Another representative embodiment of the present invention will be described. FIG. 3 shows the principle of the embodiment of the present invention.

As shown in FIG. 3A, a plurality of blocks 11 are used as areas where the scanning line 3 reads the white reference area 1.
Divided into

FIG. 3B shows an average value of the output values of the individual pixels read out of the blocks 11 obtained by dividing the white reference area 1 without any dust 2. is there. That is, the block 11 has no portion where the output is reduced due to the dust 2 and has a flat output waveform as a whole.

FIG. 3C shows the average value of the output values output from the individual pixels read out of the blocks 11 obtained by dividing the white reference area 1 among the blocks 11 having the dust. is there. That is, only the block 11 where the dust is present has a portion where the output is reduced due to the dust 2, but the output value of the read pixel that has read the dust is smaller than the output value at the point where the dust is read in the average value. Are alleviated and become smaller.

As shown in FIG. 3D, the amount of decrease in the read output caused by reading the dust attached to the mirror is reduced by the decrease in the read output caused by reading the dust attached to the white reference area 1. Although it is not larger than the amount, it occurs in all the scanning lines, so even in the average value calculated from the output values of the individual read pixels, there is no change in the decrease amount of the output value, and the same output value is applied to all the blocks. Is seen to decrease.

From the principle described above, the average value of the output values of the individual read pixels read by dividing the white reference area 1 into a plurality of predetermined blocks 11 is calculated,
It is possible to identify the block 11 that has read the dust 2 attached to the white reference area 1 by examining the average value and detecting a decrease in the read output,
Further, if the decrease in the read output is detected in all blocks, the detected dust can be determined to be dust attached to the mirror.

Next, a method of actually generating the white reference from the average value of the output values of the individual read pixels read by dividing the white reference area 1 into a plurality of predetermined blocks 11 will be described. .

In the method shown in FIG.
Is divided into a plurality of blocks 11 determined in advance, and the average value of the output values of the individual read pixels read.
In this method, the maximum value of the average values of the output values of the individual read pixels appearing in the individual blocks is used as a white standard.

That is, in the example shown in FIG. 6, a portion where the average value of the read output values due to dust is reduced in the second block is seen here, but the maximum value in the fourth block constitutes the white reference. By adopting as an element, a decrease in the read output value due to dust detected in the second block is ignored.

Further, as shown in FIG. 9, when the read output value decrease due to the dust is caused by dust adhering to the mirror, the same read output decrease is observed in all the blocks. By adopting the block having the largest value as an element constituting the white reference, the generated white reference includes a decrease in the output value due to the reading of dust attached to the mirror.

In the method shown in FIG.
Is divided into a plurality of blocks 11 determined in advance, and the average value of the output values of the individual read pixels read.
This is an embodiment of a method for eliminating a block in which the dust attached to the white reference area is detected.

The average value is calculated for each block from the average value of the output values of the individual read pixels read by dividing the white reference area 1 into a plurality of blocks 11 determined in advance. Next, the calculated average value for each block is compared, and the data relating to the block showing a prominently small value (in the example of FIG. 7, the data of the second block)
From the remaining blocks (that is, the first, third, fourth, and fifth blocks in the example of FIG. 7) in which the average value for each block indicates the maximum value (that is, in the example of FIG. 7, Is the fourth block) to obtain the individual read output values constituting the white reference.

Thus, in the initial operation of the process of generating the white reference, data relating to the block from which the dust adhered to the white reference is read is excluded, so that the influence of the dust disappears in the subsequent operations.

Further, as shown in FIG. 10, when the calculated average value for each block is compared to find out which block has a prominently small value, if the dust adheres to the mirror, it is determined by the block. Since the difference between the average values is not reflected, the reduction in the read output of each pixel due to the dust adhering to the mirror is ignored in the process of generating the white reference and is directly incorporated.

In the method shown in FIG.
Is divided into a plurality of blocks 11 determined in advance, and the average value of the output values of the individual read pixels read.
This is another embodiment according to the above-described method of eliminating a block in which dust attached to the white reference area is detected.

The average value is further calculated for each block from the average value of the output values of the individual read pixels read by dividing the white reference area 1 into a predetermined number of blocks 11. Next, the calculated average value for each block is compared, and the data relating to the block showing a prominently small value (the data of the second block in the example of FIG. 8)
, And the block in which the average value for each block indicates an intermediate value from the remaining blocks (that is, the first, third, fourth, and fifth blocks in the example of FIG. 8) (that is, in the example of FIG. 8, Is the third block) to obtain the individual read output values constituting the white reference.

Thus, in the initial operation of the process of generating the white reference, the data relating to the block from which the dust adhered to the white reference is read is excluded, so that the influence of the dust disappears in the subsequent operations.

Further, as shown in FIG. 11, when comparing the calculated average value for each block and examining a block having a prominently small value, if the dust adheres to the mirror, it is determined by the block. Since the difference between the average values is not reflected, the reduction amount of the read output of each pixel due to the dust attached to the mirror is ignored in the process of generating the white reference and is incorporated as it is.

In the method shown in FIG. 4, the output value of each read pixel obtained by reading a clean white reference area in advance is stored as reference teacher data, and then the white reference is generated when reading the original. By comparing and comparing the average value of the output values of the individual read pixels that read the white reference area with the teacher data, the output decrease of the read output of the read pixels due to dust attached to the white reference area is calculated. This is a method of constructing a white reference by performing correction.

That is, as shown in FIG. 4A, the scanning line 3 reads the white reference area 1 to which the dust 2 adheres, and calculates the read average value of each read pixel.

As shown in FIG. 4B, the teacher data 22 stored in the apparatus is extracted, and as shown in FIG. 4C, the read average output 21a calculated by reading the white reference area 1 is calculated. The data is compared with the teacher data 22.

The output waveform indicated by the read average output 21a calculated by reading the white reference area 1 is, for example, the read output indicated by the individual read pixels due to a change in the light amount of a light source lamp mounted on the image reading apparatus. Even if the value fluctuates, a waveform equivalent to the output waveform indicated by the teacher data 22 is shown.

Therefore, the aforementioned read average output 21a
In the above, the reduced portion of the read output value generated at the read pixel position 4 where the dust 2 is detected is corrected based on the teacher data 22 to generate a read average output 21b shown in FIG. be able to.

The method shown in FIG. 12 compares the average value of the output values of the individual pixels read from the white reference area 1 with predetermined teacher data, thereby obtaining the white reference area. This is an embodiment of a method of generating a white reference by correcting an output reduction due to dust detected in an average value of output values of the individual read pixels reading “1”.

That is, the teacher data 22 and the read average output 21a are compared and collated, and the individual ratio of the read average output 21a to the teacher data 22 in the individual read average output by each read pixel is obtained. The average ratio, which is the average value of the ratios, is determined. For example, in the example shown in FIG.
6%.

A criterion is set based on the average ratio. The setting range of the determination criterion is a maximum value that exceeds a variation in sensitivity of individual read pixels and detects a reduction in read output due to dust reading, and the above-described dust is dust attached to a mirror. The boundary value for detecting a decrease in the read output is set in a range where the minimum value is set. For example, in the example shown in FIG. 12, the maximum value is set to -2% for the above-mentioned average ratio of 96%, and the minimum value is set to -9% for the above-mentioned average ratio of 96%. .

This means that the following conditions were set in the example shown in FIG.

That is, the ratio of the read output to the teacher data when individual read pixels read the white reference area in the current read operation of the white reference area is 96% as an average value. It is distributed in a range up to 92% due to the variation of pixels. Further, when dust adheres to the white reference area, the read average output in the reading area of the white reference area decreases to 94% or less. However, when the dust adhering to the mirror is read, the read output decreases by less than 87%.

By setting the above-mentioned determination range with the maximum value and the minimum value, the image reading apparatus can correct only dust adhering to the white reference area when setting the white reference by the teacher data. it can.

The read average output 21a is examined according to the above-mentioned criteria, and a prominent output value is specified. That is, FIG. 12 shows an example in which a portion where the read output is 90% is considered as a target.

The output value of the protruding portion specified based on the above-described determination criterion is replaced with a value obtained by multiplying the corresponding teacher data by the above-mentioned average ratio, and the corrected read average output 21b is obtained. That is, in FIG.
Is multiplied by an average ratio of 96% to obtain a correction value of 96%.

Thus, the white reference is constituted by the average read output 21b obtained by the above correction.

Referring to FIGS. 13 to 22, a description will be given of a white reference generation flow executed by the control method of the image reading apparatus to which the present invention is applied.

FIG. 13 is a block diagram showing the structure.
That is, the image reading device B01 has the white reference area B12, and the reading unit B13 including the read pixels B14 for reading the white reference area B12 is moved by the unit moving unit B15 to set the position of the scanning line.

The read output value read by the read pixel B14 is converted into a white reference by the arithmetic control unit B10 and stored in the white reference unit B11, and is used as a reference value for generating image data in the subsequent document reading. Is done.

The memory section B16 stores procedures necessary for controlling the image reading apparatus via a computer-readable recording medium, and further stores teacher data and the like as necessary.

Further, the image data generated by the image reading device B01 is transferred to the driver program B21 of the host device B02, and a predetermined process is performed in the arithmetic control unit B20.

An operation flow according to one representative embodiment of the present invention will be described with reference to FIG. The reference numerals quoted in each step are based on FIG. The principle of the invention described in this flow is based on FIG. 1, FIG. 2 and FIG.

In step S001, the image reading device B01 receives an image reading instruction from the host device B02, and proceeds to step S002 to read the reading unit B1.
Reference numeral 3 reads a designated area of the white reference area B12.

In step S003, the average output value for each pixel of the output value obtained by reading each of the read pixels B14 from the white reference area B12 is calculated, and the average output value for the entire pixel is calculated from the average output value for each pixel. Is calculated.

In step S004, the average output value for each pixel of the output value obtained by reading the white reference area B12 by the individual read pixel B14 is compared with the total average output value, and the average output value for each pixel is obtained. In, for example, a place where an output decrease exceeding 2% of the total average output value described above is investigated.

If the above-mentioned output reduction portion is found in step S005, the flow advances to step S006 to determine that there is dust. Further, if no output reduction point is found in step S005, the flow advances to step S015 to determine that there is no dust.

If it is determined in step S006 that there is dust, the flow advances to step S007 to compare the output reduction amount determined to have dust with a predetermined reference value.

Here, a description will be given based on an example in which the predetermined reference value is set to, for example, 9% of the total average output value. That is, if the average output value for each pixel indicates an output reduction amount exceeding 9% of the total average output value, it is assumed that the output reduction due to dust is always detected at the relevant portion. Is determined to be dust attached to the mirror.

If the output reduction amount determined as having dust in step S008 is smaller than 9% of the total average output value set in the above example, the flow advances to step S009 to remove dust adhering to the white reference area B12. When it is determined that the dust has been detected, an operation of setting a white reference corresponding to dust is executed in step S010.

The operation of setting the white reference corresponding to dust executed in step S010 may be performed by a white reference setting method according to a flowchart described later.

In the step S008, the output reduction amount is:
If it is greater than the total average output value of 9% set in the above example, the process proceeds to step S017, where it is determined that the dust is dust attached to the mirror, and the above-described step S017 is performed.
As in the case where it is determined in step 015 that there is no dust, step S
Proceeding to 016, a white reference is constructed using the average output value for each pixel calculated in step S003.

In step S011, the arithmetic control unit B10 executes reading of the document in accordance with the reading instruction of the host device B02, and proceeds to step S012 to generate image data based on the white color reference.
Proceeding to 3, the image data is transferred to the host device B02.

Here, for example, when the reading area in the white reference area B12 is sufficiently large, and the image data required for the image reading apparatus B01 is, for example, binary data, in FIG. The process jumps from the step S003 to the step S016 as shown, and the individual read pixels B14 calculated in the step S003 generate the white reference using the average output value for each pixel of the output value obtained by reading the white reference area B12. Is also good.

Referring to FIG. 15, an operation flow according to another representative embodiment of the present invention will be described. The reference numerals quoted in each step are based on FIG. The principle of the invention described in this flow is based on FIG. 3 and FIG.

In step S101, the image reading apparatus B01 receives an image reading instruction from the host apparatus B02, and proceeds to step S102 to divide the white reference area B12 into blocks. The divided block is shown in FIG.
According to (a).

At step S103, the reading unit B1
3 reads the first block of the white reference area B12, proceeds to step S104, and calculates the average output value for each read pixel of the output value obtained by reading the first block by each read pixel B14, and step S105. Then, the average output value for each read pixel is temporarily stored in the arithmetic and control unit B10.

At step S106, the reading unit B1
3 reads the second block of the white reference area B12, and proceeds to step S107 to calculate an average output value for each read pixel of the output value obtained by reading the second block by each read pixel B14.

In step S108, the arithmetic and control unit B10 specifies an average output value of a specific read pixel. That is, initially, the average output value of the first read pixel is specified.

In step S109, the average output value by the first read pixel specified in the second block and the average output value by the corresponding read pixel in the temporarily stored first block (ie, the first output value). (The average read value of the first read pixel in the block).

In step S110, if the average output value of the first read pixel specified in the second block is larger than the average output value of the first read pixel in the first block, step S11 is performed.
Proceeding to 1, the average output value of the first read pixel in the temporarily stored first block is rewritten to the average output value of the first read pixel specified in the second block.

In step S110, the average output value of the first read pixel specified in the second block is equal to or equal to the average output value of the first read pixel in the first block. If the average output value of the first read pixel in the block is larger than the average output value of the first read pixel, the process proceeds to step S112, and the average output value of the first read pixel specified in the second block is erased without performing rewriting.

If the designation of the read pixel to be compared and collated in step S113 is continued, the process returns to step S108, and the subsequent comparison pixel (in this case, the second scanned pixel) is designated and the same comparison and collation is performed. Thereafter, similar comparison and collation are sequentially performed on the third read pixel, the fourth read pixel, and the individual read pixels until the last read pixel is obtained.

If the comparison and collation for all the read pixels are completed in step S113, the process proceeds to step S1.
Proceeding to 14, the subsequent block is confirmed, and if there is a subsequent block, the flow returns to step S106 to read the subsequent block, and thereafter, the same comparison and collation are sequentially performed on each block until the final block is reached.

When the comparison and comparison of the average output values of the individual read pixels in all the blocks in step S114 are completed, the average output value of the finally remaining individual read pixels becomes the average of the individual read pixels. It is composed of the maximum value.

In step S115, the average output value of the finally read individual read pixels is determined as a white reference, and stored in the white reference section B11.

In step S116, the arithmetic and control unit B10 executes reading of the document in accordance with the reading instruction of the host device B02, and proceeds to step S117 to generate image data based on the white reference, and in step S11
Proceeding to 8, the image data is transferred to the host device B02.

An operation flow according to another representative embodiment of the present invention will be described with reference to FIG. The reference numerals quoted in each step are based on FIG. The principle of the invention described in this flow is based on FIG.

In step S121, the image reading apparatus B01 receives an image reading instruction from the host apparatus B02, and proceeds to step S122 to read the reading unit B1.
Reference numeral 3 reads a designated area of the white reference area B12.

In step S123, an average output value for each read pixel of the read value of each of the read pixels B14 reading the designated area of the white reference area B12 is calculated. In the following description, the average output value for each read pixel of the output value obtained by reading the designated area of the white reference area B12 is referred to as data A.

In step S124, the data A is temporarily stored in the arithmetic and control unit B10.

In step S125, the white reference area B12 is divided into blocks. The divided block is shown in FIG.

At step S126, the reading unit B1
Reference numeral 3 reads the first block of the white reference area B12, and proceeds to step S127 to calculate the average output value for each read pixel of the output value of each read pixel B14 reading the first block. In the following description, the average output value for each read pixel of the output value obtained by reading the first block obtained by dividing the white reference area B12 is referred to as data B1. Further, similarly, an average output value for each read pixel of the output value obtained by reading the second block is referred to as data B2, and data B3, B4, and the like are hereinafter referred to as names corresponding to the read blocks.

In step S128, the data B1 is temporarily stored in the arithmetic and control unit B10.

If the block to be read remains in step S129, the flow returns to step S126 to read the subsequent block. Here, in order to read the second block following the first block, the process returns to step S126.

In the above step S129, B1, which is the average output value for each read pixel for all blocks,
If B2 and the like can be temporarily stored in the arithmetic and control unit B10, the process proceeds to step S130 to set the white reference.

According to FIG. 17, the aforementioned step S130 is performed.
The details of the setting of the white reference in are described.

In step S141, the operation control unit B
10, data B1, data B2, etc., which are temporarily stored, are extracted and sequentially compared with data A, and the aforementioned data B1,
The portion where the read output is reduced in the data B2 or the like is investigated.

If a portion where the read output is lowered is found in step S142, the flow advances to step S143 to determine that dust is detected from the block, and step S144 is performed.
The data of the average output value for each read pixel of the output value obtained by reading the block in which the dust is detected is deleted.

In step S145, a specific block is selected from the data of the average output value for each read pixel of the output value read from the remaining block.

According to FIG. 18, the above-mentioned step S145 is performed.
A typical example of a method for selecting a specific block will be described below.

In step S161, the average value of the data of the average output value for each read pixel of the output value read from the remaining individual block is calculated.

In step S162, a block whose average value indicates the maximum value is selected.

In step S163, the data of the average output value for each pixel of the block whose average value indicates the maximum value is designated as the white reference.

According to FIG. 19, the aforementioned step S145 is performed.
Another representative example of a method of selecting a specific block will be described in FIG.

In step S171, the average value of the average output value data for each read pixel of the output value read from the remaining individual block is calculated.

In step S172, the number N of the remaining blocks is counted.

If the number N of remaining blocks exceeds 1 in step S173, the flow advances to step S174 to delete the block in which the average value of the average output value data for each read pixel of the block has the minimum value. .

If the number N of remaining blocks exceeds 1 in step S175, the flow advances to step S176 to delete the block in which the average value of the average output value data for each read pixel of the block has the maximum value. .

If the number N of remaining blocks exceeds 1 in step S177, the process returns to step S174.

Steps S173 and S17 described above
5 and the number N of blocks remaining in step S177
Becomes 1, the process proceeds to step S178, and the data of the average output value for each read pixel of the remaining block is designated as the white reference.

By the above-described operation, the image reading apparatus deletes the block with dust from the average value of the read pixels in the white reference area divided into blocks and reads the white reference area with the block indicating the median value of the remaining blocks. The initial target white reference can be generated based on the average values of the read pixels.

According to FIG. 20, the aforementioned step S145 is performed.
Another representative example of a method of selecting a specific block will be described in FIG.

In step S181, the average output value of each read pixel is calculated based on all data of the average output value for each read pixel of the output value read from the remaining individual block.

In step S182, the data of the average output value of each of the read pixels is designated on a white basis.

By the operation described above, the image reading apparatus deletes the block with dust from the average value for each read pixel in the white reference area divided into blocks and reads the white reference area with the block indicating the median value of the remaining blocks. The initial target white reference can be generated based on the average values of the read pixels.

The data A generated in step S141 and the data B1 generated in step S127,
Since B2 and the like commonly include a reduced output portion obtained by reading dust attached to the mirror, dust attached to the mirror even after comparison and collation in the subsequent steps shown in FIGS. 18, 19, and 20. Is not detected, and the generated white reference includes dust adhering to the mirror.

Returning to FIG. 17, the description of the white reference setting flow will be continued.

In step S 146, FIG.
The white reference specified by the block selected in FIG. 9 or FIG. 20 is determined and stored in the white reference section B11.

Returning to FIG. 16, the description will be continued.

In step S131, the arithmetic and control unit B10 reads the original in accordance with the read instruction of the host device B02, and proceeds to step S132 to generate image data based on the white reference, and in step S13
Proceeding to 3, the image data is transferred to the host device B02.

Referring to FIG. 21, an operation flow according to another representative embodiment of the present invention will be described. The reference numerals quoted in each step are based on FIG. The principle of the invention described in this flow is based on FIG. 4 and FIG.

In step S201, the image reading apparatus B01 receives an image reading instruction from the host apparatus B02, and proceeds to step S202 where the arithmetic control unit B10 pulls out the teacher data stored in the memory unit B16 and waits.

In step S203, the reading unit B
Reference numeral 13 reads the designated area of the white reference area B12.

In step S204, an average output value for each read pixel of the output value obtained by reading the white reference area B12 by each read pixel B14 is calculated.

In step S205, in each read pixel B14, the average output value of each read pixel is individually compared with the corresponding teacher data to calculate a pixel ratio.

In step S206, an average ratio, which is an average value of the pixel ratios calculated for the individual read pixels B14, is calculated.

In step S207, a criterion for dust detection is set. That is, here, an example in which a range of 2% is set as a criterion for dust detection with respect to an average ratio of 96% according to the example of the setting range shown in FIG. This means that it is determined that dust has been detected at a portion where the pixel-by-pixel ratio calculated for the individual read pixels B14 is 94% or less.

In step S208, the pixel-by-pixel ratio calculated for each of the read pixels B14 is checked, and the flow advances to step S209 to set the reference 2 shown in the above-described example of setting the criterion.
If an output reduction portion exceeding% is found, it is determined that dust has been detected, and the process proceeds to step S210 to determine the type of the detected dust.

The type of the detected dust is determined according to the average ratio 9 according to the example of the setting range shown in FIG.
An example in which a range of 9% is set as a criterion for detecting dust adhering to a mirror for 6% will be described. This means that it is determined that dust adhering to the mirror has been detected at a location where the pixel-by-pixel ratio calculated for the individual read pixel B14 is 87% or less. That is, in the above-described example, it is determined that dust adhering to the white reference area has been detected in a portion where the pixel-by-pixel ratio calculated for the individual read pixel B14 is 94% or less and 87% or more. I have.

If it is determined in step S211 that dust has adhered to the white reference area, the flow advances to step S212 to set a white reference by correction.

According to FIG. 22, the aforementioned step S212 is performed.
The details of the flow for setting the white reference by the correction in the above will be described.

In step S221, the read pixel B14 determined to have dust attached to the white reference area is specified.

In step S222, a correction value is generated for the average read output value of the read pixel for which it has been determined that dust has been detected in the average output value for each read pixel. That is, the correction value is obtained by extracting data corresponding to the read pixel identified as having detected the dust from the teacher data, and multiplying the teacher data by the average ratio.

In step S223, the average read output value of the read pixel for which it has been determined that dust has been detected in the average output value for each read pixel is calculated in step S2.
Replace with the correction value generated in 22.

In step S224, the data of the average output value for each read pixel subjected to the above-mentioned correction is designated as the white reference, and stored in the white reference section B11.

Returning to FIG. 21, the description of the flow will be continued.

In step S213, the arithmetic and control unit B10 executes reading of the document in accordance with the reading instruction of the host device B02, and proceeds to step S214 to generate image data based on the white reference, and in step S21
Proceeding to 5, the image data is transferred to the host device B02.

If no dust is detected in step S209, the flow advances to step S217 to specify the average output value for each read pixel calculated in step S204 as the white reference, and to the white reference section B11. Then, the process proceeds to step S213.

If it is determined in step S211 that dust has adhered to the mirror, it is determined that dust has newly adhered to the mirror, and the flow advances to step S218 to correct the data at the corresponding location in the teacher data. That is, the correction of the teacher data is performed according to the flow described with reference to FIG.

The flow advances to step S 217 to designate a white reference based on the average output value for each read pixel calculated in step S 204, store it in the white reference section B 11, and further advances to step S 213.

By adopting this control method, the image reading apparatus can generate the original target white reference based on the teacher data while eliminating the output reduction due to the read dust.

[0216]

According to the present invention, the following effects can be expected.

1) In the control method of the image reading device, the average output value of the individual read pixels that read the white reference area was calculated, and the average output value of the individual read pixels and the individual read pixels were read. By comparing and comparing the average value of all the output values, the presence of dust attached to the optical path in the apparatus is detected.

2) In the control method of the image reading apparatus described above, the level of decrease in the average output value of the individual read pixels that read the white reference area is observed, and the presence of the dust is detected. It is determined whether the dust is attached to the optical path other than the white reference area.

By taking these means, the image reading apparatus can remove the element reading the dust attached to the white reference area from the output reduction portion included in the read output value of the individual read pixel reading the white reference area. The effect of determining is obtained.

3) In the control method of the image reading apparatus, the average output value of the individual read pixels that have read the white reference area is calculated, and the average output value of the individual read pixels constitutes the white reference.

By adopting this means, the image reading apparatus has an effect of producing only the white reference and attenuating only the output reduction amount generated by reading the dust adhered to the white reference area by each read pixel. .

4) In the control method of the image reading apparatus, the white reference area is divided into a plurality of blocks divided in the sub-scanning direction, and the white reference area is read in units of the blocks. By calculating the average output value of the read pixels and comparing and comparing the average output values of the individual read pixels calculated for each of the individual blocks, a white standard that eliminates the influence of dust attached to the optical path in the apparatus is obtained. Constitute.

5) In the control method of the image reading apparatus described above, the white reference is constituted by the maximum value of the average output value of the individual read pixels calculated for each block.

6) In the control method of the image reading apparatus described above, the average output value of the individual read pixels calculated for each block is compared and compared between the blocks, and the block having the lowered output portion is identified. The block is identified as a dust detection block, and the remaining blocks excluding the dust detection block constitute a white reference.

7) In the control method of the image reading apparatus, a block having the largest average value is selected from the remaining blocks excluding the dust detection block, and is set as a white reference.

8) Alternatively, in the method of controlling the image reading apparatus, a block having an average value of an intermediate value is selected from the remaining blocks excluding the dust detection block and is set as a white reference.

9) Alternatively, in the method of controlling the image reading apparatus, an average value of individual read pixels is calculated from the remaining blocks excluding the dust detection block to form a white reference.

10) Alternatively, in the above-described method of controlling the image reading apparatus, in the average output value of the individual read pixels calculated for each individual block, the output drop portion that is equally detected in all the blocks is white. It is determined that dust has adhered to the optical path other than the reference area, and a white reference is formed by including the above-mentioned output reduction portion.

By taking these means, the image reading apparatus avoids the block in which dust is read from the average value of the read output values of the individual read pixels read by dividing the white reference area into blocks, and There is an effect that a white reference is constituted by a block portion having no mark.

11) In the control method of the image reading apparatus, the average output value of the individual read pixels which read the white reference area is calculated, and the average output value of the individual read pixels is compared with the teacher data provided in advance. By collation, the presence of dust attached to the optical path in the device is detected

12) In the control method of the image reading apparatus described above, the level of the output decrease of the average output value of the individual read pixels that read the white reference area is compared with the teacher data, and the dust whose presence is detected is removed. It is determined whether dust adhered to the white reference area or dust attached to the optical path other than the white reference area, and it is determined that the detected dust is dust attached to the white reference area. In this case, the average output value is corrected based on the teacher data to form a white reference.

13) In the control method of the image reading apparatus described above, the level of the output decrease of the average output value of the individual read pixels which read the white reference area is compared with the teacher data, and the dust whose presence is detected is removed. It is determined whether the dust attached to the white reference area or the dust attached to the optical path other than the white reference area, and the detected dust is the dust attached to the optical path other than the white reference area. If it is determined that there is, the teacher data is corrected and updated without correcting the average output value, thereby forming a white reference.

By taking these means, the image reading apparatus obtains the effect of correcting the read output obtained by reading the white reference area based on the teacher data and generating a white reference excluding the influence of dust.

14) A procedure in which the image reading device calculates an average output value of the individual read pixels that read the white reference area, the average output value of the individual read pixels, and the read of the individual read pixels. And a procedure for comparing and comparing the average value of all the output values with the average value of the output values is stored in a computer-readable recording medium.

15) Alternatively, the image reading device may divide the white reference area into a plurality of blocks divided in the sub-scanning direction, and may sequentially read the plurality of divided blocks, and By comparing the average output value of the individual read pixels with the average output value of the individual read pixels calculated for each individual block, the influence of dust attached to the optical path in the apparatus is reduced. A control program for executing the procedure for configuring the excluded white reference is stored in a computer-readable recording medium.

16) Alternatively, a procedure for calculating an average output value of individual read pixels that have read the white reference area, a procedure for extracting teacher data provided in advance, and a procedure for calculating the average output value of the individual read pixels and the teacher data Is stored in a computer-readable recording medium to execute the procedure of detecting the presence of dust adhering to the optical path in the apparatus by comparing and checking the above, and forming a white reference excluding the influence of the dust. .

By taking these means, the image reading apparatus performs a procedure of generating a white reference by avoiding only an output reduction portion where dust adhering to the white reference region is read from a read output obtained by reading the white reference region. The effect of equipping is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the principle of the present invention.

FIG. 2 is an explanatory view showing the principle of the present invention.

FIG. 3 is an explanatory view showing the principle of the present invention.

FIG. 4 is an explanatory view showing the principle of the present invention.

FIG. 5 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 6 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 7 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 8 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 9 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 10 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 11 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 12 is an explanatory diagram of an operation according to a representative embodiment of the present invention.

FIG. 13 is a block diagram showing a configuration according to a representative embodiment of the present invention.

FIG. 14 is a flowchart according to a representative embodiment of the present invention.

FIG. 15 is a flowchart according to a representative embodiment of the present invention.

FIG. 16 is a flowchart according to a representative embodiment of the present invention.

FIG. 17 is a flowchart according to a representative embodiment of the present invention.

FIG. 18 is a flowchart according to a representative embodiment of the present invention.

FIG. 19 is a flowchart according to a representative embodiment of the present invention.

FIG. 20 is a flowchart according to a representative embodiment of the present invention.

FIG. 21 is a flowchart according to a representative embodiment of the present invention.

FIG. 22 is a flowchart according to a representative embodiment of the present invention.

FIG. 23 is an explanatory diagram showing a principle according to a conventional technique.

FIG. 24 is an explanatory diagram showing a principle according to a conventional technique.

FIG. 25 is an explanatory diagram of an operation according to a tabular embodiment of the related art.

FIG. 26 is an explanatory diagram of an operation according to a typical embodiment of the prior art.

FIG. 27 is a flowchart according to a representative embodiment of the prior art.

FIG. 28 is a flowchart according to a representative embodiment of the prior art.

[Explanation of symbols]

 1: White reference area 2: Dust 3: Scan line 4: Read pixel position 11: Block 21a, 21b: Read average output 22: Teacher data B01: Image reading device B02: Host device B10: Operation control unit B11: White reference unit B12: White reference area B13: Reading unit B14: Reading pixel B15: Unit moving unit B16: Memory unit

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 5C051 AA01 DB00 DB01 DB07 DE13 EA08 5C062 AA05 AB17 AC02 AC21 AC58 AC72 BA00 5C072 AA01 BA11 BA20 LA15 RA16 UA03 UA20

Claims (16)

[Claims] 1. A control method for an image reading device, comprising: calculating an average output value of individual read pixels that have read a white reference area; and calculating an average output value of the individual read pixels and an average output value of the individual read pixels. A method for controlling an image reading device, comprising detecting the presence of dust attached to an optical path in the device by comparing and comparing the average value of all output values read. 2. The method of controlling an image reading apparatus according to claim 1, wherein the level of the output decrease of the average output value of the individual read pixels that read the white reference area is observed, and the presence of the dust is detected. The method according to claim 1, wherein it is determined whether the dust adheres to the optical path or the dust adheres to an optical path other than the white reference area. 3. The method for controlling an image reading apparatus according to claim 1, wherein an average output value of each of the read pixels obtained by reading the white reference area is calculated, and a white reference is formed using the average output value of the individual read pixels. The control method of the image reading device according to claim 1, wherein: 4. A method for controlling an image reading apparatus, comprising: dividing a white reference region into a plurality of blocks divided in a sub-scanning direction, reading the white reference region in units of the blocks, and Calculates the average output value of the read pixels of the above, and compares and averages the average output values of the individual read pixels calculated for each of the individual blocks, thereby eliminating the influence of dust attached to the optical path in the apparatus. A method for controlling an image reading device, comprising: 5. The method for controlling an image reading device according to claim 4, wherein a white reference is constituted by a maximum value of an average output value of the individual read pixels calculated for each block. 3. The method for controlling an image reading device according to 1. 6. The method for controlling an image reading device according to claim 1, wherein the average output value of the individual read pixels calculated for each block is compared and compared between the blocks, and a block having a reduced output portion is identified. The control method of the image reading device according to claim 4, wherein the white reference is configured by remaining blocks excluding the dust detection blocks, the blocks being identified as dust detection blocks. 7. The method for controlling an image reading apparatus according to claim 1, wherein a block having the largest average value is selected from the remaining blocks excluding the dust detection block, and is used as a white reference. A method for controlling the image reading device according to claim 6. 8. The method for controlling an image reading apparatus according to claim 1, wherein a block whose average value is an intermediate value is selected from the remaining blocks excluding the dust detection block and is used as a white reference. The method for controlling an image reading device according to claim 6. 9. The method for controlling an image reading apparatus according to claim 1, wherein an average value of individual read pixels is calculated from the remaining blocks excluding the dust detection block to form a white reference. The method for controlling an image reading device according to claim 6. 10. A control method for an image reading apparatus according to claim 1, wherein, in an average output value of said individual read pixels calculated for each individual block, an output drop portion detected equally in all blocks is defined as a white reference area. The method according to claim 4, wherein it is determined that dust adhered to an optical path other than the above, and the white reference is configured by including the output reduction portion. 11. A method for controlling an image reading apparatus, comprising: calculating an average output value of individual read pixels obtained by reading a white reference area; and comparing the average output value of the individual read pixels with teacher data provided in advance. A method for controlling an image reading device, characterized in that the presence of dust attached to an optical path in the device is detected by collation. 12. The method for controlling an image reading apparatus according to claim 1, wherein the level of the decrease in the average output value of the individual read pixels that have read the white reference area is compared with the teacher data to detect dust that has detected the presence. It is determined whether the dust adheres to the white reference area or the dust adheres to an optical path other than the white reference area. It is determined that the detected dust is dust adhering to the white reference area. 12. The method according to claim 11, wherein the average output value is corrected based on the teacher data to form a white reference. 13. The method for controlling an image reading apparatus according to claim 1, wherein the level of reduction in the average output value of the individual read pixels that have read the white reference area is compared with the teacher data to detect the presence of the dust. It is determined whether the dust attached to the white reference area or the dust attached to the optical path other than the white reference area, and the detected dust is dust attached to the optical path other than the white reference area. The control method of the image reading device according to claim 11, wherein when it is determined that there is, the teacher data is corrected and updated without correcting the average output value to form a white reference. . 14. A recording medium storing a control program for realizing control of the image reading device, wherein the image reading device calculates an average output value of individual read pixels obtained by reading a white reference area; A computer readable program which stores a control program for executing an average output value of an individual read pixel and a procedure of comparing and comparing the average output value of all the read output values of the individual read pixel. Recording medium. 15. A recording medium storing a control program for realizing control of an image reading device, wherein the image reading device divides a white reference region into a plurality of blocks divided in a sub-scanning direction. A step of sequentially reading the blocks divided into a plurality of pieces and calculating an average output value of the individual read pixels for each block; and comparing and comparing the average output values of the individual read pixels calculated for the individual blocks. A computer-readable recording medium storing a control program for executing a procedure for forming a white reference by eliminating the influence of dust attached to an optical path in the apparatus. 16. A recording medium for storing a control program for controlling an image reading apparatus, comprising: a step of calculating an average output value of individual read pixels obtained by reading a white reference area; and a step of extracting teacher data provided in advance. Comparing the average output value of the individual read pixels with the teacher data to detect the presence of dust adhering to the optical path in the apparatus, and forming a white reference excluding the influence of the dust. A computer-readable recording medium storing a control program to be executed.