JP2002247354A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader which compares the shading sample data of a white board with the shading sample data stored in a memory and, in the case that there is a difference, urges the user to reinput a white board data. SOLUTION: White board data are written on the white board, and this image reader compares the value with the white board data within the memory, and in the case that they are different, this updates the data within the memory, and changes the multiplication coefficient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus using a CCD, such as a copying machine, which forms an image by shading sample data obtained by reading a light distribution by a mechanical / optical system from a white correction plate, which is generated in data obtained by reading an original. It relates to shading correction for correcting data.

FIG. 1 schematically shows a typical image reading apparatus. Reference numeral 101 denotes a white correction plate serving as a white reference;
Is a manuscript. A light source 103 is a light source such as a halogen lamp, a fluorescent lamp, or a xenon tube. Reference numeral 104 denotes a reflection shade, which is provided for efficiently using the light source. Reference numerals 105-a, 105b and 105c denote mirrors which move left and right so as to keep the optical path length from the document surface to the CCD line image sensor 107 constant. 106 is a lens.

[0003]

2. Description of the Related Art In conventional image reading, a sensor output when a light source is not turned on is set as a black reference, and a sensor output obtained by reading a white correction plate with a light source turned on is set as a white reference. Was corrected. Particularly, in an image reading apparatus for reading a color original,
In order to reproduce the color by the combination of each output (usually RGB) of the CD sensor, the data of the white correction plate (data on what level this correction plate should be read) is attached, and the shading sample which read the white correction plate Shading correction was performed based on the data and the white correction plate data (FIG. 2).

[0004]

However, the white correction plate is replaced. However, unless the data of the white correction plate is updated, the captured image cannot be corrected correctly, and the image data according to the original desired by the user, or There is a problem that image output cannot be obtained.

To solve this problem, by automatically recognizing the replacement of the white correction plate and automatically updating the white correction plate data or prompting the user to update the white correction plate data,
Outputs the image exactly as desired by the user.

[0006]

According to the present invention, there is provided an image reading apparatus having the following configuration.

In an image reading apparatus which performs shading of image data on a white correction plate by a CCD linear image sensor using shading data read by a CCD linear image sensor, a shading sample is performed at a predetermined position and shading data is obtained. An image reading apparatus which compares the backup data with the backup data and informs the user of the effect of the replacement of the white board on the image based on the comparison result.

In the above image reading apparatus, the comparison between the shading data and the backup data is performed when the power is turned on or at predetermined intervals.

[0009] In the above image reading apparatus, the backup data may store shading sample data at the time of manufacture or data shading sampled at predetermined intervals.

In an image reading apparatus for shading a target image with a CCD linear image sensor using shading data read by a CCD linear image sensor on a white correction plate, data of the white correction plate is placed on the white correction plate. Is written,
An image reading apparatus wherein the backup data is compared with the backup data when the white correction plate data is read, and the backup data is updated if different.

In the above image reading apparatus, the comparison between the white correction plate data and the backup data is performed when the power is turned on or at predetermined intervals.

[0012] In the above image reading apparatus, the backup data may store white correction plate data at the time of manufacture.

[0013]

(First Embodiment) FIG. 3 shows a first embodiment of the present invention. FIG. 3 shows the configuration of the present invention. 3
01 is a CCD linear image sensor (hereinafter abbreviated as CCD), 302 is an analog signal processing circuit (hereinafter abbreviated as AP) for processing analog signals of the CCD, and 303 is an AP
An analog signal processing circuit (hereinafter abbreviated as A / D) 304 for converting the output of the A / D into a digital signal is a shading correction circuit 304 for performing shading correction on an image signal output from the A / D. 305, a line memory 1; division means of 309; multiplication count of 310;
Multiplication means. A line memory 306 stores shading data. Further, the line memory 306 can be backed up. A comparison circuit 307 notifies the CPU 308 of the result. 3
An operation unit 12 is connected to the CPU.

Further, the multiplication coefficient 310 is connected to the CPU 308 and can be controlled from the CPU.

Next, the operation will be described. Normally, the data obtained by reading the white color correction plate is stored in the line memory 1 305, and the output data of the A / D is read by the dividing means 309 using the shading data stored in the line memory 1 305 when reading the original. The result of division is multiplied by the multiplication count of 310 by the multiplication means of 311 to correct the output.

When storing shading sample data as a reference at the time of manufacture or at a predetermined interval, the shading sample data is stored in the line memory 306.

305 line memory 1 when reading an image
The shading sample data stored in the line memory 2 and the shading data stored in
The comparison circuit 07 compares the result, and transmits the result to the CPU 308. If the difference is large, a display prompting “re-input of white correction plate data” is displayed on the operation unit 312. When the user inputs the white correction plate data from the operation unit, 308
Change the multiplication coefficient of 310 via the CPU.

The following is a calculation formula for shading.

Dout (n) = Din (n) × K / S (n) Dout (n): Shading output of the nth pixel Din (n): Shading circuit input signal of the nth pixel K: White correction plate data S (N): Shading sample data of the nth pixel Next, control will be described. FIG. 4 shows a control sequence according to the first embodiment of the present invention.

First, the reading position is moved onto the white color correction plate. Next, the lamp is turned on and a shading sample is performed. The shading sample data stored in the line memory 1 is compared with the shading data stored in the line memory 2. If the result is different, a message prompting the user to “re-enter the white correction plate data” is issued to the operation unit to warn the user. When the white correction plate data is input from the user, the shading sample data is stored in the backup data, and the white correction plate data input by the user is updated as a multiplication coefficient.

If the data comparison results are the same or different, the above processing is performed, then the reading position is returned to the home position, the lamp is turned off, and a series of comparison confirmation operations is completed.

In data comparison, data for each pixel may be simply compared. However, it is hard to say that the same result will be obtained even in the completely same environment due to the influence of a reading error and S / N. Therefore, for example, the difference between the shading sample data and the shading data is calculated, and if the difference between the pixels is equal to or less than a predetermined level, it is considered that the difference is the same. You may decide that they are the same.

If a series of comparison operations are performed every time an image is read, the productivity of the image reading apparatus may be reduced. Therefore, the comparison operation may be performed immediately after the power is turned on or at predetermined time intervals.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention. FIG. 5 shows the configuration of the present invention. 501 is C
A CD 502 is an AP for processing analog signals of a CCD.
503 is an A / A that converts the output of the AP into a digital signal.
In D, reference numeral 504 denotes a shading correction circuit for performing shading correction on the image signal output from the A / D, and includes a line memory 505, a dividing means 506, a multiplication count of 508, and a multiplication of 507. Have a means.
Reference numeral 510 denotes a conversion circuit for converting the output of the shading circuit 504, and reference numeral 511 denotes a memory. 512 is 51
The comparison circuit compares the value obtained by the output conversion circuit of 0 with the value stored in the memory of 511. The result is 509
Is input to the CPU. The multiplication count of 508 can be changed by the CPU of 509.

Next, the operation will be described. Normally, similarly to the first embodiment, the data read from the white color correction plate is stored in the line memory 505, and the output data of the A / D is stored in the line memory 505 by the dividing means 506 when the original is read. The output is corrected by multiplying the result by the multiplication factor of 508 by the multiplication means of 507.

When storing data of a reference white correction plate at the time of manufacture or at predetermined intervals, an image output obtained from a shading circuit 504 is converted into white correction plate data by an output conversion circuit 510, and 511. Is compared with the previous white correction plate data stored in the memory. 512
The comparison circuit compares the white correction plate data obtained by converting the output with the white correction plate data stored in the memory 511 and inputs the data to the CPU 509. According to the comparison result, if the data is the same, the multiplication coefficient of 508 is changed as it is, and if the data is different, the multiplication coefficient is changed to a read value.

Next, the control will be described. FIG. 6 shows a control sequence according to the second embodiment of the present invention. First, the reading position is moved to a position on the white correction plate where the white correction plate data is written. Next, the lamp is turned on and the image is read. The white correction plate data is taken in from the read values.
The acquired white correction plate data A is compared with the white correction plate data B stored in the memory. If the comparison results are different, the acquired white correction plate data A is written into the white correction plate data B stored in the memory.

When the data comparison results are the same or when the data stored in the memory is updated, the white correction plate data B stored in the memory is written in the multiplication coefficient C, the home position is moved, the lamp is turned off, and The automatic recognition operation of is ended.

As described above, the method of converting the read value is shown in FIG.
This can be handled by writing a bar code 702, which is a bar code of the white correction plate data, on a white correction plate 701 like the white correction plate shown in FIG. White of the white correction plate,
If the barcode is black, it is easy to determine whether the barcode is white or black even without shading correction, and it is possible to capture the data from the output signal of the shading correction circuit that does not perform shading correction.

[0030]

In the image reading apparatus, the shading sample data at the time of manufacture is compared with the shading sample data at the time of shading sample, and the multiplication coefficient and the white correction plate data are updated based on the result, thereby replacing the white correction plate. It can automatically recognize that it has been done. As a result, it is possible to prevent the image from being unable to be read correctly.

[Brief description of the drawings]

FIG. 1 Image reading device

[Fig. 2]

FIG. 3 shows a first embodiment.

FIG. 4 is a first flowchart.

FIG. 5 shows a second embodiment.

FIG. 6 is a second flowchart.

FIG. 7 is a bar code of a white correction plate shape.

[Explanation of symbols]

 Reference Signs List 101 White correction plate 102 Document 103 Light source 104 Reflector shade 105 Mirror 106 Lens 107 CCD linear image sensor 108 Document glass 301 CCD linear image sensor 302 Analog signal processing circuit 303 A / D conversion circuit 304 Shading correction circuit 305 Line memory 1 306 Line memory 2 307 Comparison circuit 308 CPU 309 Division means 310 Multiplication coefficient 311 Multiplication means 312 Operation unit 501 CCD linear image sensor 502 Analog signal processing circuit 503 A / D conversion circuit 504 Shading correction circuit 505 Line memory 506 Division means 507 Multiplication means 508 Multiplication coefficient 509 CPU 510 Output conversion circuit 511 Backup data 512 Comparison circuit 701 White correction plate 702 Bar code

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 5B047 AA01 BA02 BB02 CA02 CB01 DA04 DC06 5C062 AA05 AB42 AC22 AC58 AE07 BA06 5C072 AA01 BA08 FB12 FB25 RA16 UA02 UA12 5C077 MM03 PP06 PP71 PQ24 SS01

Claims (6)

[Claims] 1. Using a shading data read by a CCD linear image sensor on a white correction plate,
In an image reading device that performs shading of image data on a target image by a CCD linear image sensor,
An image reading apparatus which performs shading sampling at a predetermined position, compares shading data with backup data, and informs a user of an influence on an image due to replacement of a white board based on a comparison result. 2. The image reading apparatus according to claim 1, wherein the comparison between the shading data and the backup data is performed at power-on or at predetermined intervals. 3. The image reading apparatus according to claim 1, wherein the backup data stores shading sample data at the time of manufacturing or data shading-sampled at predetermined intervals. 4. Using a shading data read by a CCD linear image sensor on a white correction plate,
In an image reading device that performs shading of image data on a target image by a CCD linear image sensor,
An image reading apparatus in which data of a white correction plate is written on a white correction plate, the data is compared with backup data when reading the white correction plate data, and if different, the backup data is updated. 5. The image reading apparatus according to claim 4, wherein the comparison between the white correction plate data and the backup data is performed when the power is turned on or at predetermined intervals. 6. The image reading apparatus according to claim 4, wherein the backup data stores white correction plate data at the time of manufacture.