JPH10290329A - Original reading method, device therefor and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original reading method capable of preventing an original size from being mis-detected due to flaws on a pressure plate. SOLUTION: The reflected light of an original scanned by a scanner mechanism 115 is photoelectric-converted by a CCD 101, an original size detection circuit 106 detects an original size from an output signal from the CCD 101, preliminary scanning is conducted prior to the substantial scanning and a system controller 114 recognizes mis-detected position. Then the mis-detected position is stored in a page memory 111 and the mis-detected position is excluded from a detected area by the system controller 114 at the substantial scanning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original reading method and apparatus for reading an original using a line sensor such as a CCD (image pickup device) and a storage medium used for the original reading method and apparatus.

[0002]

2. Description of the Related Art Conventionally, in a copying machine, when detecting the size of a document placed on a platen glass, the size of the document is detected using a sensor dedicated to document size detection (hereinafter referred to as a sensor). There is a case where the size of the document is detected from the read image data by performing pre-scanning (hereinafter referred to as pre-scan detection). There are disadvantages.

The former sensor detection has the advantage that the size of the document can be detected without performing prescan, but requires a sensor dedicated to document size detection.
There is a demerit that a sensor is required according to the size of a document to be generally detected.

In the latter case of the pre-scan detection, there is an advantage that a sensor dedicated to document size detection is not required, and it is possible to detect a document other than a standard size, but there is a disadvantage that the pre-scan must be performed without fail. .

Also, a problem in the case of the pre-scan detection is an erroneous detection due to a flaw on a pressure plate for pressing an original placed on a platen glass.

The prescan detection method will be described below with reference to FIG. FIG. 21 is a plan view of the platen glass viewed from above. In the figure, reference numeral 2101 denotes an original platen glass, 2102 denotes an original (hatched portion), and an upper left corner indicates an original reference position, and indicates that the original 2102 is placed based on the position.

In FIG. 21, P1, P2, P3
Is the position in the sub-scanning direction, K1 is a scratch on the silver pressing plate, V-SYNC
Is a synchronization signal for each page, V-ENBL is a signal indicating an effective line section within one page period, H-SYNC is a synchronization signal for each line, and H-ENBL indicates an effective image data section within one line period. Signal.

In the pre-scan detection, the platen glass 21
In the state where the original 2102 is not placed on the original 01, the side of the original holder that is in contact with the original platen glass 2101 totally reflects the light and prevents the light from being incident on the image reading CCD (not shown). Is adopted.

Therefore, original 2 is placed on original platen glass 2101.
When the pre-scan is performed while the document 102 is placed, the original 2
The position where the document 102 is placed is scanned, and the original 2102 is scanned.
Light is incident on the CCD according to the density of the light. On the other hand, manuscript 2
At the position where the light source 102 is not mounted, the light is totally reflected by the pressure plate (silver pressure plate) and does not enter the CCD as described above.
A difference occurs in the output signal level of the CCD. The position of the document 2102 is obtained using this level difference.

This will be described with reference to FIGS. 21 and 22. When prescanning is performed from the reference position on the original platen glass 2101 in FIG. 21 in the scanning direction indicated by the arrow, a CCD output signal is read at the sub-scanning direction position P1 as signal 1 in FIG. In FIG. 22, a dotted line indicates a threshold level, and a portion exceeding the threshold level indicates that the surface of the document 2102 is being read. At the position P2 in the sub-scanning direction, the CCD output signal is read as signal 2 in FIG. In FIG. 22, since the CCD output signal does not exceed the threshold level, it is determined that the document 2102 does not exist at the sub-scanning direction position P2. Original 21 based on this level difference
02 "Upper-Left", "Lower-Le
ft "," Upper-Right "," Lower-
By obtaining the coordinates of “Right”, the size of the document 2102 is detected.

[0011]

However, in the above-mentioned conventional example, when a flaw K1 is present on the corresponding pressure plate on the sub-scanning direction position P3 in FIG. 21, a signal 3 in FIG. However, since the output signal of the CCD exceeds the threshold level even though it is not on the original surface, there is a problem that an erroneous detection of the original size occurs.

Also, when foreign matter adheres to the pressure plate or the document glass 2101 is dirty, there is another problem that the document size is erroneously detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and a first object of the present invention is to prevent an erroneous detection of an original size due to a scratch on a pressure plate. It is an object of the present invention to provide an original reading method and apparatus.

A second object of the present invention is to provide a method for detecting an erroneous document size in response to a user when the erroneous detection of the document size is caused by the adhesion of a foreign substance to a pressure plate or the contamination of a platen glass. It is an object of the present invention to provide a document reading method and apparatus capable of avoiding the problem.

Further, a third object of the present invention is to provide a storage medium capable of smoothly controlling the above-described document reading apparatus.

[0016]

According to a first aspect of the present invention, there is provided an original reading method for reading an original by scanning means, and a method of reflecting the original scanned by the scanning means. A photoelectric conversion step of photoelectrically converting light by photoelectric conversion means, a document size detection step of detecting the size of a document by a document size detection means from an output signal from the photoelectric conversion means, and scanning in advance before the original scanning. An erroneous detection position recognizing step of recognizing the erroneous detection position by the erroneous detection position recognizing means; an erroneous detection position storing step of storing the erroneous detection position by the erroneous detection position storing means; An erroneous detection position excluding step of excluding the erroneous detection position from the detected area.

According to a second aspect of the present invention, there is provided an original reading method for reading an original by a scanning unit, wherein the reflected light of the original scanned by the scanning unit is photoelectrically converted. Means for performing photoelectric conversion by means, means for detecting the size of the document by means of the document size detection means from the output signal from the photoelectric conversion means, and scanning in advance before the original scanning to recognize erroneously detected positions. A false detection position recognition step of recognizing a false detection position by means, and a false detection position display step of displaying the false detection position recognized by the false detection position recognition means on a display means.

According to a third aspect of the present invention, there is provided an original reading apparatus, comprising: scanning means for reading an original; and photoelectric conversion means for photoelectrically converting reflected light of the original scanned by the scanning means. Converting means; document size detecting means for detecting the size of the document from the output signal from the photoelectric conversion means; erroneous detection position recognizing means for performing scanning before performing original scanning to recognize erroneous detection positions; An erroneous detection position storage unit for storing a detection position, and an erroneous detection position exclusion unit for excluding the erroneous detection position from the detected area during the original scanning.

According to a fourth aspect of the present invention, there is provided an original reading apparatus, comprising: scanning means for reading an original; and photoelectric conversion means for photoelectrically converting reflected light of the original scanned by the scanning means. Converting means; document size detecting means for detecting the size of the document from the output signal from the photoelectric conversion means; erroneous detection position recognizing means for performing scanning before performing original scanning to recognize erroneous detection positions; An erroneous detection position display unit for displaying the erroneous detection position recognized by the detection position recognition unit.

According to a fifth aspect of the present invention, there is provided an original reading method for reading an original by a scanning unit, and photoelectrically converting reflected light of the original scanned by the scanning unit. Means for performing photoelectric conversion by means, means for detecting document size by means of document size detection means from output signals from the photoelectric conversion means, and means for varying the size of the detected area by means of area size control means And a region size control step.

According to a sixth aspect of the present invention, there is provided an original reading method according to the fifth aspect, wherein the erroneous original size detection is generated by the erroneous original size detection occurrence recognizing means. A document size erroneous detection occurrence recognizing step for recognizing that the document size erroneous detection occurrence recognizing means detects that the document size erroneous detection has occurred; And a detected area control step of controlling the area.

According to a seventh aspect of the present invention, there is provided an original reading apparatus, comprising: scanning means for reading an original; and photoelectric conversion means for photoelectrically converting reflected light of the original scanned by the scanning means. The image processing apparatus further includes a conversion unit, a document size detection unit that detects a size of the document from an output signal from the photoelectric conversion unit, and an area size control unit that changes the size of the detected area.

According to another aspect of the present invention, there is provided a document reading apparatus for detecting a document size error in which the document size error detection has occurred. Generation recognition means, and detection area control means for controlling a detection area so that erroneous detection does not occur when the document size erroneous detection occurrence recognition means recognizes that erroneous document size detection has occurred. Features.

In order to achieve the third object, a storage medium according to a ninth aspect is a storage medium for storing a program for controlling an original reading apparatus for reading an original, wherein the original is read by scanning means. A reading module, a photoelectric conversion module for photoelectrically converting reflected light of the document scanned by the scanning means by photoelectric conversion means, and a document size for detecting the size of the document by document size detection means from an output signal from the photoelectric conversion means A detection module, a misdetection position recognition module for performing scanning before the original scanning and recognizing the misdetection position by the misdetection position recognition means, and a misdetection position storage for storing the misdetection position by the misdetection position storage means A module and an erroneous detection position at which the erroneous detection position is excluded from the detected area by the erroneous detection position elimination means during the original scanning And characterized by storing a program having an outer module.

In order to achieve the third object, a storage medium according to a tenth aspect is a storage medium for storing a program for controlling a document reading device for reading a document,
A document reading module for reading a document by scanning means,
A photoelectric conversion module that photoelectrically converts reflected light of a document scanned by the scanning unit by a photoelectric conversion unit, a document size detection module that detects a document size by a document size detection unit from an output signal from the photoelectric conversion unit, An erroneous detection position recognition module for performing scanning in advance before the original scanning and recognizing the erroneously detected position by the erroneously detected position recognition means; A program having a detection position display module is stored.

In order to achieve the third object, a storage medium according to claim 11 is a storage medium for storing a program for controlling a document reading device for reading a document,
A document reading module for reading a document by scanning means,
A photoelectric conversion module that photoelectrically converts reflected light of a document scanned by the scanning unit by a photoelectric conversion unit, a document size detection module that detects a document size by a document size detection unit from an output signal from the photoelectric conversion unit, A program having an area size control module for making the size of the detected area variable by the area size control means is stored.

According to a twelfth aspect of the present invention, in the storage medium according to the twelfth aspect, the program is such that the erroneous document size detection is performed by the erroneous document size detection occurrence recognition means. The document size error detection occurrence recognition module for recognizing the occurrence of the error and the document size error detection occurrence recognition means so that when the document size error detection is recognized to have occurred, the detected area control means does not cause the false detection. And a detected area control module for controlling the detected area.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(First Embodiment) First, the first embodiment of the present invention will be described.
An embodiment will be described with reference to FIGS. FIG.
FIG. 1 is a block diagram illustrating a configuration of an image processing portion of a digital copying machine that is an image processing apparatus including a document reading device according to a first embodiment of the present invention. In the figure, first, an image signal (R, G, B) read from a CCD (image pickup device) 101 is supplied to a sample & hold circuit (S / H).
Circuit) 102, and is converted into a digital signal by an A (analog) / D (digital) converter 103. The shading correction circuit 104 corrects a signal variation for each pixel in the main scanning direction before scanning a document. Note that the shading correction operation of the shading correction circuit 104 is a well-known technique in the related art, and thus the description thereof is omitted.

The masking circuit 105 converts the RGB signals corrected by the shading correction circuit 104 into standard RGB signals in consideration of the characteristics of the CCD 101 and the color filters. The original size detection circuit 106 has an erroneous detection mask function and has the highest level signal (hereinafter referred to as M) of the RGB signals output from the masking circuit 105.
AX-RGB signal) to detect the size of the original from the image signal. This is to improve the detection accuracy for the background color of the document.

The data conversion circuit 107 generates density data from RGB signals. After the data conversion circuit 107, image signal processing is performed on the density data. The memory data controller 108
The flow of the density data output from the data conversion circuit 107 is switched to a scaling circuit 109, a compression / expansion circuit 110, and a halftone processing circuit 112 according to the processing. The memory data controller 108 switches the flow of the density data output from the scaling circuit 109 to the compression / expansion circuit 110 or the halftone processing circuit 112 according to the processing, or outputs the density data from the compression / expansion circuit 110. The flow of the density data is transmitted to the scaling circuit 109 and the halftone processing circuit 1
The process is switched to 12 according to the processing.

The density data output from the memory data controller 108 is output after the halftone processing circuit 112 performs processing such as screen processing and error diffusion processing corresponding to the printer 113. Compression / expansion circuit 11
The density data output from 0 is stored in the page memory 111. The system controller 114 performs settings for each processing block.

Here, an interrupt signal is output to the system controller 114, and in the interrupt processing, the system controller 114 performs setting according to the document size. This setting operation will be described later.

The scanner mechanism (scanning mechanical section) 115
It is composed of a motor for scanning, a mirror base, an optical system guide rail, and the like. The display unit 116 sets each mode and displays a message.

FIG. 2 is a block diagram showing the configuration of the document size detection circuit 106 with the erroneous detection mask function in FIG. The document size detection circuit 106 is a comparator 2
01, matrix processing circuit 202, FIFO 203, timing generation circuit 204, H-counter 205, V-counter 206, misdetection address registers 207, 20
8, 209, a document address register 210 and a mask signal generation circuit 211.

In FIG. 2, MAX-RGB is the highest level signal among the RGB signals output from the masking circuit 105 of FIG. 1, H-enb is a signal indicating an effective image data section within one line period, VCLK is a video clock signal, H-sync is a synchronization signal for each line, V-end is a signal indicating an effective line section within one page period, V-sync is a synchronization signal for each page,
CPU-DATA is the C of the system controller 114.
This is a data signal from the PU.

MAX from masking circuit 105 in FIG.
The RGB signal is input to the input unit A of the comparator 201. Also, the input section B of the comparator 201 has:
A threshold value is set according to the density level of the document whose size is detected as the value of the register of the document size detection circuit 106 from the system controller 114 in FIG.

In the comparator 201, the CCD 1 shown in FIG.
The output signal of 01 is compared with the threshold value for each pixel, and when A> B, “H (High)” is output. In the matrix processing circuit 202, the comparator 2
From the output of 01, it is determined whether or not the original is being read. Further, the comparator 201 has a comparison operation permission signal ENB terminal. This comparison operation permission signal E
The NB terminal has Mask0 of the mask signal generation circuit 211.
The signal terminal is connected. When the comparison operation enable signal ENB terminal output is “H”, the comparison result is output and “L”
In this case, the comparison output is always "L". Here, it is determined from the output of the comparator 201 whether or not the original is being read. The FIFO 203 holds data for a plurality of lines in the sub-scanning direction in the matrix processing circuit 202.

The timing generation circuit 204 generates a control signal for the matrix processing circuit 202 and the FIFO 203, and also generates an address read request signal which is an interrupt signal to the system controller 114. The H-counter 205 is an up counter in the main scanning direction.
H-counter 2 with synchronization signal H-sync for each line
05 is reset, and the signal H-enb indicating the valid image data section within one line period is set to “L (Low)”.
When, the count-up operation is performed. Clock input:
A video clock signal VCLK of a pixel clock is input. In the present embodiment, A4
In the case of a vertical (297 mm) size original, (297 /
25.4) Since * 600 = 7014 is the maximum required count number, a 13-bit (bit) binary counter is used here.

The V-counter 206 is an up counter in the sub-scanning direction. Synchronization signal V-syn for each page
c, the V-counter 206 is reset, and the signal V-enb indicating an effective line section within one page period becomes “L (L
ow) ", the count is incremented every time a rising edge of the signal H-sync is input. In the sub-scanning direction, (420/25) in the case of vertical (420 mm) of an A3-size document. .4) *
Since 600 = 9921 is the maximum required count number, a 14-bit (bit) binary counter is used here.

Misdetection address registers 207-209
Is an address register when an erroneous detection occurs. In the mask signal generating circuit 211, an operation permission signal Mask0 of the comparator 201 is output from a Mask0 signal terminal based on the values of these registers 207 to 209. The document address register 210 stores “Up”
per-Left "," Lower-Left "," U
"pper-Right", "Lower-Right"
H-counter 205 and V-counter 2
06 is stored. Here, the writing operation of the document address register 210 will be described later.

The mask signal generation circuit 211 generates a mask signal, and is configured as shown in FIG.
3 is a block diagram showing the configuration of the mask signal generation circuit 211. As shown in FIG. 3, the mask signal generation circuit 211 includes comparators 301, 302, 303, 304,
305, 306, 307, 308, 309, 310, 3
11,312, JK F / F313,314,31
5,316,317,318, AND gates 319,3
20, 321 and an OR gate 322.

As shown in FIG. 2, the mask signal generation circuit 2
To 11, output signals of the H-counter 205, the V counter 206, and the erroneously detected address registers 207 to 209 are respectively input.

That is, focusing on the first AND gate 319, the V of the first false detection address register 207
Is compared with the value of the V-counter 206 by the first comparator 301, and the comparison output is the first JK
The signal is input to the J terminal of the F / F 313. Similarly, the V register value of the first erroneous detection address register 207 and the value of the V-counter 206 + the matrix size are compared by the second comparator 302, and the comparison output is the first J value.
-K Input to the K terminal of F / F 313. Similarly, the H register value of the first false detection address register 207 and the value of the H-counter 206 are compared by the third comparator 303, and the comparison output is used as the second JK F / F3
14 are input to the J terminal. Similarly, the value of the H register value + matrix size of the first false detection address register 207 and the value of the H-counter 206 are stored in the fourth comparator 30.
4 and the comparison output is the second J-K F /
It is input to the K terminal of F314. And the first and second
The comparison output from each output terminal Q of the JK F / Fs 313 and 314 is input to the input terminal of the first AND gate 319. Further, the input terminal of the first AND gate 319 receives the H-enb signal. The output of the first AND gate 319 is “H” when the H-enb signal is “L”.
H ”, and the first and second JK F / F31
When the comparison output from each of the output terminals Q of 3,314 is "H", it is masked to "L".

Similarly, focusing on the second AND gate 320, the V register value of the second false detection address register 208 and the value of the V-counter 206 are compared by the fifth comparator 305. The output is the third J-
It is input to the J terminal of KF / F315. Similarly, the value of the V register of the second false detection address register 208 and the value of the V−counter 206 plus the matrix size are equal to the sixth.
And the comparison output is input to the K terminal of the third J-K F / F 315. Similarly, the value of the H register of the second false detection address register 207 and the value of the H-counter 206 are compared with the values of the seventh comparator 307.
And the comparison output is the fourth J-K F / F
316 is input to the J terminal. Similarly, the value of the H register value + matrix size of the second false detection address register 208 and the value of the H-counter 206 are the same as those of the eighth comparator 3.
08, and the comparison output is the fourth J-K F
/ F316 is input to the K terminal. The comparison output from each output terminal Q of the third and fourth JK F / Fs 315 and 316 is input to the input terminal of the second AND gate 320. Further, an H-enb signal is input to an input terminal of the second AND gate 320. The output of the second AND gate 320 becomes “H” when the H-enb signal is “L”, and the third and fourth JK F / Fs
The comparison output from each output terminal Q of 315 and 316 is "H".
At this time, it is masked to "L".

Similarly, focusing on the third AND gate 321, the register value of V of the third false detection address register 209 and the value of the V-counter 206 are compared by the ninth comparator 309, and the comparison is performed. The output is the fifth J-
It is input to the J terminal of KF / F317. Similarly, the register value of V of the third false detection address register 209 and the value of V−counter 206 + matrix size are equal to the first.
0 and the comparison output is the fifth
Is input to the K terminal of the J-K F / F 317. Also,
Similarly, the register value of H of the third false detection address register 209 and the value of the H-counter 206 correspond to the values of the eleventh comparator 3.
11 and the comparison output is the sixth JK F
/ F318 is input to the J terminal. Similarly, the twelfth comparator 312 compares the register value of H of the third false detection address register 209 with the matrix size and the value of the H-counter 206, and compares the comparison output with the sixth J-
It is input to the K terminal of KF / F318. Then, each output terminal Q of the fifth and sixth JK F / Fs 317 and 318
Is input to the input terminal of the third AND gate 321. Further, the input terminal of the third AND gate 321 receives the H-enb signal. Third AND
The output of the gate 321 becomes “H” when the H-enb signal is “L”, and further, the fifth and sixth JK F /
The comparison output from each output terminal Q of F317 and 318 is "
At the time of "H", it is masked and becomes "L".

First to third AND gates 319 to 321
Mask signals (Mask 01, M
Ask02, Mask03) are input to the OR gate 322 and output as a Mask0 signal.

Next, the address storing operation of the document address register 210 of the document size detection circuit 106 will be described with reference to FIGS.
This will be described with reference to FIG. 4 and 5 are flow charts for sequentially explaining the address storing operation of the document address register 210 of the document size detecting circuit 106.
7A and 7B are diagrams for explaining an address storing operation of the document address register 210 of the document size detection circuit 106.

In FIG. 4, first, a prescan is started in step S401. Next, in step S402, the output GEN of the matrix processing circuit 202 (see FIG. 2)
Is changed from "L" to "H", that is, whether the scan position reaches the document surface. And GEN
If L = L, that is, if the scan position does not reach the document surface, the flow advances to step S403 to determine whether the scan for one line has been completed. If the scanning for one line is not completed, the process proceeds to step S402.
Return to G
If EN = H is not satisfied, the process proceeds to step S404, where the V-counter 206 (see FIG. 2) is incremented, and then returns to step S402 to change the output GEN of the next line from "L" to "H". Determine whether it has changed.

As described above, if GEN = H in step S402, that is, if the scan position has reached the document surface, in step S405, the H-counter 205 and V-counter at that time are set. The value of 206 is stored in LL1 (H, V).

Next, in step S406, it is determined whether or not GEN has changed from "H" to "L", that is, whether or not the scan position is no longer on the document surface until the scan position is no longer on the document surface. And when GEN = L,
That is, if the scan position is no longer on the document surface, the H-counter 205 and V
-Store the value of the counter 206 in LR1 (H, V).
Then, in step S408, LL1 (H,
The value of (V) is stored in UL (H, V) as the position of “Upper-Left” of the document. Then, step S4
At 09, the V-counter 2 waits for data of the next line.
After incrementing 06, the process proceeds to step S410.

In this step S410, the output GEN of the matrix processing circuit 202 for the data of the next line is "
It is determined whether or not L has changed from "L" to "H", that is, whether or not the scan position has reached the document surface.
, The H- at that time is determined in step S411.
The values of the counter 205 and the V-counter 206 are set to LL2
(H, V). Next, in step S412, it is determined whether or not the output GEN of the matrix processing circuit 202 has changed from “H” to “L” until it changes from “H” to “L”. Then, when the output GEN = L, in step S413, the H-counter 205 and V-
After storing the value of the counter 206 in LR2 (H, V),
The process proceeds to step S501 in FIG.

In this step S501, the previous line LL
1 value of the H-counter 205 “LL1 (H)” and the current value of the H-counter 205 of the line LL2 “LL2 (H)”
LL2 (H) is larger than LL1 (H) to determine whether "LL1 (H) <LL2 (H)". And when LL2 (H) is larger than LL1 (H),
In step S502, it is determined whether the upper-right document position (UR) has been set. If the UR has not been set, the process proceeds to step S503.
Is set to U-R as the upper-right document position.
After storing (H, V), the process proceeds to step S504.

The storing operation in step S503 will be described using the coordinates of the HV counter in FIG. Now, UL (H, V) is stored, and then the prescan proceeds, and LL2 (H) of GEN = H is always smaller than the previous line. The relationship between LL1 (H) and LL2 (H) is based on the upper right of the document position (Upper-Right).
Continue until. And for the first time, LL1 (H) <LL2 (H)
UR (H, V) is determined at the time of.

Returning to FIG. 5, the aforementioned step S501 is executed again.
In, if LL2 (H) is not greater than LL1 (H) and if the UR is already set in step S502, the process proceeds to step S504.

In step S504, the previous line LR
The value “LR1 (H)” of the H-counter 205 of “1” and the value “LR2 (H)” of the H-counter 205 of the current line LR2
LR1 (H) is larger than LR2 (H) to determine whether “LR1 (H) <LR2 (H)”. And when LR1 (H) is larger than LR2 (H),
In step S505, it is determined whether or not the Upper-Left original position (UL) has been set. If the UL has not been set, the process proceeds to step S506.
In the upper-left document position, LL (H,
After storing V), the process proceeds to step S507.

In step S504, LR1
If (H) is not greater than LR2 (H) and if the UL has been set in step S505, the process proceeds to step S507.

In step S507, the address of the current line is set as the previous line data. That is, LL1 (H,
V) = LL2 (H, V) and LR1 (H, V) = LR2
(H, V). Next, in step S508, the V counter 206 is incremented to wait for data of the next line. Next, in step S509, the Lower-Left
It is determined whether the original document position (LL) and the original document position (U-R) of Upper-Right have been set. If the LL and UR have not been set,
The process returns to step S410 in FIG. From there, U-
This operation is repeated until both R and LL are stored in the register.

In step S509, L
If -L and UR have been set, step S51
0, the output GEN of the matrix processing circuit 202
Is changed from "L" to "H".
H ”. If the output GEN = H, the values of the H-counter 205 and V-counter 206 at that time are set to LL1 in step S511.
After storing in (H, V), the process proceeds to the next step S512.

In this step S512, it is determined whether or not the output GEN of the matrix processing circuit 202 has changed from "H" to "L" until it changes from "H" to "L".
Then, if the output GEN = L, step S
After storing the values of the H-counter 205 and V-counter 206 at that time in LR1 (H, V) at 513, the V counter 206 is incremented to wait for data of the next line at the next step S514, Step S5
Return to 10.

On the other hand, in step S510, the output GEN of the matrix processing circuit 202 changes from "L" to "H".
If not, it is determined in step S515 whether one line has been completed. If one line has not been completed, the process returns to step S510. If the original has not been confirmed after one line has been completed, the process returns to step S5.
At 16, the lower right (LR) above the document position is the previous line, so LL1 (H, V) is stored as LR (H, V). Next, an address read request signal is output in step S517 to cause the system controller 114 to read the address, and then the present processing operation ends.

In this manner, the addresses of the four corners on the document surface are obtained.

In the actual machine, the system controller 114 obtains the size of the document from the four addresses thus obtained, and uses this document size information for various processes such as scaling.

In this description, the sequential operation has been described with reference to a flowchart. However, the operation is the same even if it is constituted by a logic circuit.

When the inclination of the original 2002 is reversed as shown in FIG. 6, actually, in step S4 of FIG.
08, the address stored is L instead of UL.
-L, which should be determined by reading the register by the system controller 114,
Here, the description is omitted.

Next, the output GE of the matrix processing circuit 202
N will be described with reference to FIGS. 8 and 9. FIG.
Matrix processing circuit 202 and FIFO 20 in FIG.
FIG. 3 is a block diagram showing a configuration of No. 3; The matrix processing circuit 202 includes an AND gate 801 and OR gates 802, 8
03, DF-F804, 805, 806, 807, 80
Eight.

In FIG. 8, Co10 is a matrix size signal in the sub-scanning direction, Row0 is a matrix size signal in the main scanning direction, and Din is a comparison result signal between the image signal (MAX-RGB signal) in the comparator 201 and a predetermined threshold level. When the image signal exceeds the threshold level, a high level is output, and when the image signal does not exceed the threshold level, a low level is output. P
clk is a video clock signal, Clk0 is a clock signal corresponding to the matrix size in the main scanning direction, F-clk
Is a read / write clock signal of the FIFO 203,
F-enb is a read / write permission signal for the FIFO 203.

In FIG. 9, Pclk is a video clock signal, H-sync is a synchronization signal for each line,
H-enb is a signal indicating an effective image data section within one line period, Din is a comparison result signal between the image signal (MAX-RGB signal) in the comparator 201 and a predetermined threshold level, and the image signal has exceeded the threshold level. In this case, a high level is output, and if the threshold level is not exceeded, a low level is output. R
ow0 is a matrix size signal in the main scanning direction, Co10
Is a matrix size signal in the sub-scanning direction, Gen0 is a document size detection result output signal, Clk0 is a clock signal corresponding to the matrix size in the main scanning direction, and F-clk is F
I / O read / write clock signal, F-
enb is a read / write permission signal for the FIFO 203.

The matrix size signals Co10 and Row
0 determines the matrix size of the document presence / absence.
It is output from the timing generation circuit 204 of FIG. The signal Din is output from the comparator 201 in FIG.

The operation of the matrix processing circuit 202 will be described with reference to the timing chart of FIG. here,
This is a case of a 4 × 4 matrix size of 4 pixels in the main scanning direction and 4 lines in the sub-scanning direction.

The signal Din is connected to a 4-bit shift register. Only when all of these four outputs are "H", that is, when the comparator output determines that the output is on the document surface, A
The output of the ND gate 801 becomes H.

As shown in FIG. 9A, when the matrix size signals Co10 and Row0 are both H and the DF-F
708 and the AND gate 8 by the clock signal Clk0
01 is latched. The clock signal Clk0 is
It is output only once in four cycles of the video clock signal Pclk. In this way, the result is written to the FIFO 203 every four pixels in one line. The matrix size signal Co10 has a four-line cycle as shown in FIG. 9B because the processing is performed in a four-line cycle in the sub-scanning direction.

Next, an erroneous detection removal operation due to a scratch on the pressure plate of the document reading apparatus according to the present embodiment will be described with reference to the flowchart of FIG.

First, the power is turned on in step S1001, and initial control is performed in the next step S1002.
The system controller 114 in FIG. 1 confirms driving of the scanner mechanism 115 in FIG. 1 which is a scanning system. Next, a prescan is performed in step S1003. At this time, of course, nothing must be placed on the platen glass and the platen must be closed.

Next, in step S1004, the system controller 114 in FIG. 1 outputs the three erroneously detected address registers 207 of the original size detecting circuit 106 in FIG.
209 (see FIG. 2) is determined whether data is set (whether there is a flaw on the pressure plate). If no data is set in the erroneous detection address registers 207 to 209, it is determined that there is no flaw on the pressure plate, and there is no erroneous detection. Accordingly, the process waits for a key input (scan wait) in step S1005. After entering, this processing operation ends.

On the other hand, the false detection address register 207
If data is set in any one of 圧 209, it is determined that there is a flaw on the pressure plate, and step S1006 is performed.
After masking the signal of the erroneously detected point by the mask signal generation circuit 211 in FIG. 3, the process returns to the step S1003 to perform the pre-scan again to confirm the presence or absence of a flaw on the pressure plate.

In this embodiment, a configuration is provided in which three erroneous detection address registers are provided, and the signal of the erroneously detected point is masked by the mask signal generation circuit 211 to detect the original size of the original to be scanned. But if
When three or more flaws are present on the pressure plate, it can be easily dealt with by increasing the number of mask signal generation units of the mask signal generation circuit 211 in FIG.

The mask signal generation circuit 2 shown in FIG.
In 11, the mask signal is generated with a width of the matrix size in both the main scanning and the sub-scanning. However, the masking may be made wider than the matrix size as long as the required detection accuracy allows.

Further, when an erroneous detection has occurred at a plurality of points, the system controller 114 can arbitrarily set an adjacent portion in the mask signal generation circuit 211 so that the adjacent portion can be masked by one mask signal. A circuit may be provided so that a mask signal can be generated by providing a register.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. 11 and 12. FIG. Note that the basic configuration of a digital copying machine, which is an image processing apparatus provided with the document reading apparatus according to the present embodiment, is the same as that of FIGS. 1 to 3 in the above-described first embodiment. This will be described with reference to FIG.

In the present embodiment, when it is determined that there is a flaw on the pressure plate, the position of the flaw is displayed on the display unit so that the user can confirm the position of the flaw. In practice, erroneous detections due to foreign matter sticking or dirty platen glass can be easily removed at the user level.

FIG. 11 is a flowchart showing the operation of displaying the erroneous detection position of the document reading apparatus according to the present embodiment on the display unit, and FIG. 12 is a diagram showing the display unit displaying the erroneous detection position. is there.

In FIG. 11, first, at step S110
1, the power is turned on, and initial control is performed in the next step S1102, and the system controller 114 (see FIG. 1) operates as a scanning mechanism 115 (see FIG. 1) which is a scanning system.
Confirm mechanical drive of. Next, step S11
At 03, a prescan is performed. At this time, of course, nothing must be placed on the platen glass and the platen must be closed. Next, in step S1104, the system controller 114 causes the document size detection circuit 1
06 (see FIG. 1)
It is determined whether data is set in 7 to 209 (see FIG. 2) (whether there is an erroneous detection). If no data is set in the erroneous detection address registers 207 to 209, it is determined that there is no erroneous detection, and the next step S
After entering a key input waiting (scan waiting) state in 1105, the present processing operation is ended.

On the other hand, if data is set in any one of the erroneously detected address registers 207 to 209 in step S1104, it is determined that erroneous detection has been made, and in the next step S1106, the system controller 1
Reference numeral 14 reads a value in which data is stored from the erroneously detected address registers 207 to 209. Further, the system controller 114 displays on the display unit 116 (see FIG. 1) which side of the platen glass the read register value corresponds to. Further, the system controller 114
Is displayed on the display unit 116 by matching the address of each point with XY coordinates with the original reference position as the origin. Thereafter, the process returns to step S1103, and the pre-scan is performed again to confirm whether there is an erroneous detection.

FIG. 12 shows a case where the erroneously detected position is at three points. Looking at this display, the user checks whether or not there is any dirt, foreign matter or the like at each point.

In this checking operation, if erroneous detection cannot be removed at the level of the user (no foreign matter is attached or stained), an operation unit (not shown) can be set to mask the erroneously detected position. You may do it.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS.

FIG. 13 is a block diagram showing the configuration of a digital copying machine which is an image processing apparatus provided with the document reading apparatus according to the present embodiment.
The same reference numerals as in FIG. 1 denote the same parts in the embodiment. 13 differs from FIG. 1 in that the display unit 116 is removed from the configuration in FIG.

FIG. 14 is a block diagram showing the configuration of the original size detecting circuit in FIG. 13. In FIG. 14, the same parts as those in FIG. I have. 14 differs from FIG. 2 in that the configuration of FIG.
7 to 209, the original address register 210 and the mask signal generation circuit 211 are deleted, and the UL address register 1401, the LL address register 140
2. A UR address register 1403 and an LR address register 1404 are provided. These address registers 1401 to 1404 store “U”
paper-Left "," Lower-Left ",
“Upper-Right”, “Lower-Right”
It stores the values of the H-counter 205 and the V-counter 206, which are the coordinates of "t".

Each address register 1401-1 of the original size detecting circuit in the original reading apparatus according to the present embodiment.
The write operation of 404 is the same as that of the original address register 210 in the above-described first embodiment, and a description thereof will be omitted.

FIG. 15 is a timing chart showing the output timing of each signal in the case of eight pixels in the main scanning direction and eight lines in the sub-scanning direction. In this case, of course, the repetition is performed at a cycle of 8 pixels in one line and at a cycle of 8 lines in the sub-scanning direction. In this case, control is performed by the matrix size signals Co10 and RowO.

As described above, the matrix of the matrix processing circuit 202 can be changed by changing the timing of the control signal.

Next, an operation for removing false detection due to a flaw on the pressure plate in the original reading apparatus according to this embodiment will be described with reference to FIG.
This will be described with reference to the flowchart of FIG.

First, the power is turned on in step S1601, and initial control is performed in the next step S1602.
The system controller 114 (see FIG. 13) performs a mechanical drive check of the scanner mechanism 115 that is a scanning system. Next, a prescan is performed in step S1603.
At this time, of course, nothing must be placed on the platen glass and the platen must be closed. At this time, the matrix processing circuit 202 (FIG. 14)
4) is set as an initial value.

Next, in step S1604, the system controller 114 causes the document size detection circuit 106 (FIG.
4) address registers 1401 to 14
It is determined whether data is set in 04 (whether or not there is a flaw). Then, the address registers 1401 to 1401
If no data is set in 1404, it is determined that there is no scratch on the pressure plate, and there is no erroneous detection with this.
After entering a key input wait (scan wait) state in step S1605, this processing operation ends.

On the other hand, in step S1604, 4
If data is set in one of the address registers 1401 to 1404, it is determined that there is a flaw on the pressure plate, and the matrix size is increased to 8 × 8 in step S1606, and then the process proceeds to step S1603. Return and perform prescan again. Such processing is repeated until erroneous detection due to a flaw on the pressure plate is eliminated.

In this embodiment, the matrix size is increased until the pressure plate is no longer damaged. However, the maximum matrix size is actually determined in accordance with the required document size detection accuracy. If the erroneous detection cannot be removed even if the error is exceeded, it is desirable to output an error message. For example, when only the standard size is determined, the system controller determines from four addresses, and thus the detection accuracy requirement is low.

It is also possible to employ a configuration in which the threshold level is also changed when erroneous detection is removed. For example, when it is determined that there is a flaw, the pre-scan is performed again with the threshold level raised.

(Fourth Embodiment) Next, a storage medium according to the present invention will be described with reference to FIGS.

As shown in FIG. 17, at least a “document reading module”, a “photoelectric conversion module”, a “document size detecting module”, and a “wrong document” are stored in a storage medium for storing a program for controlling a document reading apparatus for reading a document. Detected position recognition module ”,“ False detected position storage module ”,
What is necessary is just to store the program which has each module of a "false detection position exclusion module".

Here, the "document reading module" is a program module for reading a document by the scanning means. The "photoelectric conversion module" is a program module for performing photoelectric conversion of reflected light of the document scanned by the scanning unit by the photoelectric conversion unit. The "document size detection module" is a program module for detecting the size of the document by the document size detection means from the output signal from the photoelectric conversion means. The "erroneously detected position recognition module" is a program module that performs scanning before the original scanning and recognizes the erroneously detected position by the erroneously detected position recognition means. The “erroneous detection position storage module” is a program module that stores the erroneous detection position by an erroneous detection position storage unit. The “erroneous detection position exclusion module” is a program module for excluding the erroneous detection position from the detected area by the erroneous detection position elimination means during the original scanning.

A storage medium different from the storage medium shown in FIG. 17 for storing a program for controlling an original reading apparatus for reading an original is provided with at least an "original reading module" and a "photoelectric conversion module" as shown in FIG. , A program having respective modules of “document size detection module”, “false detection position recognition module”, and “false detection position display module” may be stored.

Here, the "document reading module" is a program module for reading a document by the scanning means. The "photoelectric conversion module" is a program module for performing photoelectric conversion of reflected light of the document scanned by the scanning unit by the photoelectric conversion unit. The "document size detection module" is a program module for detecting the size of the document by the document size detection means from the output signal from the photoelectric conversion means. The "erroneously detected position recognition module" is a program module that performs scanning before the original scanning and recognizes the erroneously detected position by the erroneously detected position recognition means. The “erroneous detection position display module” is a program module that displays the erroneous detection position recognized by the erroneous detection position recognition unit on a display unit.

As shown in FIG. 19, at least a “document reading module”, a “photoelectric device”, and a storage medium storing a program for controlling a document reading device for reading a document are different from the storage media shown in FIGS. What is necessary is just to store the program which has each module of a "conversion module", a "document size detection module", and an "area size control module".

Here, the "document reading module" is a program module for reading a document by the scanning means. The "photoelectric conversion module" is a program module for performing photoelectric conversion of reflected light of the document scanned by the scanning unit by the photoelectric conversion unit. The "document size detection module" is a program module for detecting the size of the document by the document size detection means from the output signal from the photoelectric conversion means. The "region size control module" is a program module that makes the size of the detected region variable by the region size control means.

It is desirable to add a “document size error detection occurrence recognition module” and a “detected area control module” to the program stored in the storage medium shown in FIG. 17 as needed.

Here, the "document size error detection occurrence recognition module" is a program module for recognizing that document size error detection has occurred by the document size error detection occurrence recognition means. Also, "Detected area control module"
Is a program module for controlling the detected area so that the erroneous detection does not occur by the detected area control means when the erroneous document size detection is recognized by the erroneous document size detection occurrence recognizing means.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a digital copying machine that is an image processing apparatus including a document reading device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a document size detection circuit in the digital copying machine.

FIG. 3 is a block diagram showing a configuration of a mask signal generation circuit in the original size detection circuit.

FIG. 4 is a flowchart for sequentially explaining an address storage operation of a document address register in the document size detection circuit.

FIG. 5 is a flowchart illustrating an address storage operation sequence of a document address register in the document size detection circuit.

FIG. 6 is a diagram for explaining an address storage operation of a document address register in the document size detection circuit.

FIG. 7 is a diagram for explaining an address storing operation of a document address register in the document size detection circuit.

FIG. 8 is a block diagram showing a configuration of a matrix processing circuit in the original size detection circuit.

FIG. 9 is a timing chart showing timings of the matrix processing circuit when the matrix size of the signal is 4 × 4.

FIG. 10 is a flowchart illustrating an erroneous detection removal operation sequence in the document size detection circuit.

FIG. 11 is a flowchart illustrating an operation sequence for displaying an erroneously detected position on a display unit in the document reading apparatus according to the second embodiment of the present invention.

FIG. 12 is a diagram showing a state where an erroneous detection position in the document reading apparatus is displayed on a display unit.

FIG. 13 is a block diagram illustrating a configuration of a digital copying machine that is an image processing apparatus including a document reading device according to a third embodiment of the present invention.

FIG. 14 is a block diagram showing a configuration of a document size detection circuit in the digital copying machine.

FIG. 15 is a timing chart showing timings when the matrix size of the signal of the matrix processing circuit in the original size detection circuit is 8 × 8.

FIG. 16 is a flowchart illustrating an erroneous detection removal operation sequence in the document size detection circuit.

FIG. 17 is a diagram showing each module of a program stored in a storage medium of the present invention.

FIG. 18 is a diagram showing each module of a program stored in a storage medium of the present invention.

FIG. 19 is a diagram showing each module of a program stored in a storage medium of the present invention.

FIG. 20 is a diagram showing each module of a program stored in a storage medium of the present invention.

FIG. 21 is a plan view showing a state in which an original is placed on an original platen glass of the digital copying machine.

FIG. 22 is a CCD corresponding to the position on the document shown in FIG.
FIG. 3 is a diagram illustrating an output signal level.

[Explanation of symbols]

 Reference Signs List 101 CCD 102 S / H circuit 103 A / D converter 104 Shading correction circuit 105 Masking circuit 106 Document size detection circuit 107 Data conversion circuit 108 Memory data controller 109 Magnification circuit 110 Compression / expansion circuit 111 Page memory 112 Halftone processing circuit 113 Printer 114 System controller 115 Scanner mechanism 116 Display unit 201 Comparator 202 Matrix processing circuit 203 FIFO 204 Timing generation circuit 205 H-counter 206 V-counter 207 False detection address register 208 False detection address register 209 False detection address register 210 Original address register 301 Comparison Circuit 302 Comparison circuit 303 Comparison circuit 304 Comparison circuit 305 Comparison circuit 306 Comparison circuit 3 07 comparison circuit 308 comparison circuit 309 comparison circuit 310 comparison circuit 311 comparison circuit 312 comparison circuit 313 JK F / F 314 JK F / F 315 JK F / F 316 JK F / F 317 JK F / F 318 JK F / F 319 Gate 320 AND gate 321 AND gate 322 OR gate 801 AND gate 802 OR gate 803 OR gate 804 DF-F 805 DF-F 806 DF-F 807 DF-F 808 DF-F 1401 UL address register 1402 L-L address Register 1403 UR address register 1404 LR address register 2001 Platen glass 2002 Document

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Takiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Katsuya Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Naoto Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (12)

[Claims] An original reading step of reading an original by a scanning unit; a photoelectric conversion step of photoelectrically converting reflected light of the original scanned by the scanning unit by a photoelectric conversion unit; and an original from an output signal from the photoelectric conversion unit. A document size detection step of detecting the size of the document by size detection means;
An erroneous detection position recognizing step of performing scanning in advance before the original scanning and recognizing the erroneous detection position by the erroneous detection position recognizing means; and an erroneous detection position storing step of storing the erroneous detection position by the erroneous detection position storing means. An erroneous detection position exclusion step of excluding the erroneous detection position from the detected area by an erroneous detection position excluding unit during the scanning of the document. 2. A document reading step of reading a document by a scanning unit, a photoelectric conversion step of photoelectrically converting reflected light of the document scanned by the scanning unit by a photoelectric conversion unit, and a document based on an output signal from the photoelectric conversion unit. A document size detection step of detecting the size of the document by size detection means;
An erroneous detection position recognizing step of performing scanning in advance before the original scanning and recognizing the erroneous detection position by the erroneous detection position recognizing means; and displaying the erroneous detection position recognized by the erroneous detection position recognizing means on a display means. A document reading method, comprising: a detection position display step. 3. A scanning device for reading a document, a photoelectric conversion device for photoelectrically converting reflected light of the document scanned by the scanning device, and a document for detecting a size of the document from an output signal from the photoelectric conversion device. Size detection means, misdetection position recognizing means for performing pre-scanning before the original scanning and recognizing the misdetection position, misdetection position storage means for storing the misdetection position, and the misdetection position during the original scanning And an erroneous detection position exclusion unit for excluding the erroneous detection position from the detection area. 4. A scanning device for reading a document, a photoelectric conversion device for photoelectrically converting reflected light of the document scanned by the scanning device, and a document for detecting a size of the document from an output signal from the photoelectric conversion device. Size detection means, erroneous detection position recognizing means for performing scanning before the original scanning and recognizing erroneous detection positions, and erroneous detection position display means for displaying the erroneous detection positions recognized by the erroneous detection position recognition means And a document reading device. 5. A document reading step of reading a document by a scanning unit, a photoelectric conversion step of photoelectrically converting reflected light of the document scanned by the scanning unit by a photoelectric conversion unit, and a document based on an output signal from the photoelectric conversion unit. A document size detection step of detecting the size of the document by size detection means;
An area size control step of changing the size of the detected area by the area size control means. 6. A document size error detection occurrence recognizing step of recognizing that document size error detection has occurred by the document size error detection occurrence recognizing means, and a document size error detection occurrence occurring by the document size error detection occurrence recognizing means. 6. A document reading method according to claim 5, further comprising a detected area control step of controlling the detected area so that an erroneous detection does not occur by the detected area control means when the recognition is performed. 7. A scanning device for reading a document, a photoelectric conversion device for photoelectrically converting reflected light of the document scanned by the scanning device, and a document for detecting a size of the document from an output signal from the photoelectric conversion device. A document reading apparatus comprising: a size detection unit; and an area size control unit that changes a size of a detection target area. 8. An original size erroneous detection occurrence recognizing means for recognizing that an erroneous original size detection has occurred, and an erroneous detection when the original size erroneous detection occurrence recognizing means recognizes that an erroneous original size detection has occurred. 8. The document reading apparatus according to claim 7, further comprising a detected area control unit that controls the detected area so that the detected area does not occur. 9. A storage medium for storing a program for controlling a document reading device for reading a document, comprising: a document reading module for reading a document by scanning means; and a photoelectric conversion means for reflecting reflected light of the document scanned by the scanning means. A photoelectric conversion module for photoelectrically converting the original, a document size detection module for detecting the size of the document by the document size detection means from the output signal from the photoelectric conversion means, A false detection position recognition module for recognizing a false detection position, a false detection position storage module storing the false detection position by a false detection position storage unit, and a false detection position excluding unit during original scanning. A program having an erroneous detection position exclusion module excluded from the detection area. Storage medium. 10. A storage medium for storing a program for controlling a document reading apparatus for reading a document, comprising: a document reading module for reading a document by scanning means; and a photoelectric conversion means for reflecting reflected light of the document scanned by the scanning means. A document size detection module for detecting the size of a document by document size detection means from an output signal from the photoelectric conversion means, and a false detection position recognition means for performing scanning in advance before the original scanning. A program having an erroneously detected position recognizing module for recognizing the erroneously detected position, and a erroneously detected position display module for displaying the erroneously detected position recognized by the erroneously detected position recognizing means on a display means. Storage media. 11. A storage medium for storing a program for controlling a document reading device for reading a document, comprising: a document reading module for reading a document by scanning means; and a photoelectric conversion means for reflecting reflected light of the document scanned by the scanning means. Photoelectric conversion module, a document size detection module for detecting the size of a document by document size detection means from an output signal from the photoelectric conversion means, and an area for changing the size of the detected area by area size control means A storage medium storing a program having a size control module. 12. The program according to claim 1, wherein: the document size error detection occurrence recognition unit recognizes that the document size error detection has occurred; the document size error detection occurrence recognition module; and the document size error detection occurrence recognition unit detects the document size error. 12. The storage medium according to claim 11, further comprising: a detected area control module that controls the detected area so that the erroneous detection does not occur by the detected area control unit when the occurrence of the error is recognized.