JPH0846786A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain the image forming device in which an intermediate density is desired to be set to the outside of an original and the intermediate density is desired to be set to the original are processed as desired by the operator automatically by utilizing background information of the original obtained through image processing in advance so as to vary a threshold level of binarization processing in real time. CONSTITUTION:When one-lien image data are fed to a line memory 36 and a background density decision section 37, the background density decision section 37 decides the background density while the data are stored in the line memory 36 and when the background density is given to a RAM 38 as an address, a binarization threshold level in response to he background density is given to a binarization processing section 31. When image data are given from the line memory 36 to the binarization processing section 31, the image data are binarized and given to an original detection processing section 32. The detection section 32 detects a frame of the original and when the detection output is corrected, the frame is erased from the image data based on the corrected detection signal at an original outside erasure processing section 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to, for example, a digital copying machine which, when copying a thick original, makes a blank outside the original to make a copy.

[0002]

2. Description of the Related Art In recent years, as a copying machine, a digital copying machine utilizing digital technology has been developed and put into practical use. That is, a digital copying machine has been developed in which an image from an original is read by a CCD (charge coupled device) type line sensor and a signal from the line sensor is quantized and processed.

In such a digital copying machine, when a thick original such as a book is to be copied, the platen cover for pressing the original can be closed only partway, so that the outer portion of the original floats from the original table. The outside of the original becomes black when copying. For example, for thick manuscripts "AAA" and "BB
If minute areas such as "B", "CCC" and dust are present on the platen, thick originals "AAA", "BBB", "CC"
C'and dust and other small areas are copied in black.

Therefore, when copying a thick original, a copying machine has been developed which corrects areas other than the thick original to white. Such a correction function is disclosed as an in-frame area detection device described in, for example, Japanese Patent Application Laid-Open Nos. 1-150546 and 3-17787. When there are a plurality of thick originals “AAA” and “BBB” in the main scanning direction,
The area between the thick original “AAA” and the thick original “BBB” in the main scanning direction and the area between the minute area and the thick original “CCC” in the main scanning direction are not judged to be outside the original, and are black. Although there is a problem that it is formed on the screen, against such a problem, even if there are a plurality of thick originals in the main scanning direction, black is not copied between adjacent thick originals, and Japanese Patent Application No. 5-65256 proposes an image forming apparatus which does not copy black even between a minute area and an adjacent thick original.

[0005]

In a copying machine having these correction functions, a binarizing process is adopted as a process for erasing the outside of the original. In this binarizing process, a fixed threshold value is set for each page, The signal is binarized with this fixed threshold value to discriminate the outside of the document. In such a binarization process, when a book is copied with a thick book open, an intermediate density portion occurs between the outside of the original and the original. Therefore, it is desirable to set the binarization threshold value so that the intermediate density portion can be processed as the outside of the original as the outside of the original of this original. However, in the case of an original having a dark background such as a newspaper, there is a problem that the above-described binarization threshold value for copying a thick book causes the background of the original to be processed outside the original. As described above, it is difficult to determine a binarization threshold that can perform binarization processing on both a document whose intermediate density portion is outside the original document and a document whose intermediate density portion is outside the original document.

The present invention has been made in view of the above-mentioned problems, and by utilizing the background information of the original document obtained in advance by image processing, by changing the threshold value of the binarization processing in real time, Another object of the present invention is to provide an image forming apparatus capable of processing a document whose intermediate density portion is outside the original document and a document whose intermediate density portion is outside the original document as desired by an operator.

[0007]

According to the present invention, it corresponds to a converting means for converting an image having an original area and an area outside the original into an image signal, and a background from the image signal outside the original area and the outside of the original area. Background density determining means for determining the background density and generating a background density signal, reference signal generating means for generating a reference signal according to the background density, and a binarized signal by comparing the reference value and the image signal. A binarization generation unit that generates a binarized signal, an out-of-document detection unit that calculates the out-of-document area by calculating the distribution of the binarized signal, and an image by referring to the out-of-document detection signal. It is characterized by further comprising outside-original erasing means for erasing out-of-original signal components corresponding to outside the original from the signal, and image forming means for forming an image based on the image signal from which the out-of-original signal components are removed. An image forming apparatus is provided.

Further, according to the present invention, a converting means for converting an image having an original area and an area outside the original for each line to generate a one-line image signal, and an original area and an outside-of-the-origin area from the one-line image signal. Background density determining means for determining a background density corresponding to a background outside the area and generating a background density signal according to the one-line image signal; reference signal generating means for generating a reference signal according to the background density; A binarization generating means for comparing the binarization and the image signal to generate a binarization signal, and a distribution of the binarization signal to calculate a region outside the document of the one-line image to detect a region outside the document. Out-of-original detection means for generating an out-of-original detection signal, and out-of-original erasing means for erasing the out-of-original signal component corresponding to the outside of the original from the 1-line image signal with reference to the out-of-original signal Image based on image signal An image forming apparatus characterized by including the an image forming means for forming is provided.

Further, according to the present invention, a converting means for converting an image having an original area and an area outside the original into an image signal, and a background density corresponding to a background outside the original area and the outside area of the original are determined from the image signal. A background density determining means for generating a background density signal, a reference signal generating means for generating a reference signal according to the background density, and a reference value and an image signal are compared to generate a binarized signal. The binarization generation means, the out-of-document detection means for calculating the distribution of the binarized signal to detect the out-of-document area and generating the out-of-document detection signal, and one level of the binarized signal exceeds a predetermined number. If a predetermined number is not exceeded, a correction means for generating a correction signal for correcting the binarized signal and an out-of-original detection signal are referred to to detect an out-of-original signal from the image signal. The signal component outside the document corresponding to An image forming apparatus comprising: an extra-original erasing unit that corrects an image signal in response to a positive signal; and an image forming unit that forms an image based on the image signal from which the extra-original signal component is removed. Will be provided.

[0010]

In the image forming apparatus of the present invention, the reference value for binarization, that is, the threshold value is determined according to the background information.
Using this reference value, it is determined whether the area is outside the document.
Moreover, since the reference value is determined for each line of the image, it is determined for each line image whether or not the area is outside the document. Therefore, it is possible to surely perform the out-of-frame processing even for an original document whose intermediate density portion is to be excluded from the original document or an original document whose intermediate density portion is to be used as the original document.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a digital copying machine as an image forming apparatus, FIG. 2 is a plan view of an operation panel unit, and FIG. 3 is a block diagram showing a frame area detection circuit of an image processing unit.

In FIG. 1, reference numeral 11 indicates a main control section for controlling the digital copying machine as a whole. The main control unit 11 is provided with a CPU, a control program, a ROM in which parameters of an out-of-document erasure mode, which will be described later, are stored, and a RAM in which various data are stored.

An image processing unit 12 for processing an image and an operation panel unit 13 for inputting various kinds of processing as shown in FIG. 2 are connected to the main control unit 11. The image processing unit 12 includes a circuit shown in FIG. 3 which will be described in detail later, and processes image data sent from a scanner processing unit to be described later, and then compresses / expands the image data.

As shown in FIG. 2, the operation panel unit 13 is provided with a numeric keypad input unit 21 for inputting numbers, a message display unit 22 for displaying processing messages, and a print key for giving an instruction to start printing. -23, an outside-original erasing mode switch 24 for giving an instruction to erase outside of the original, and a threshold setting switch 25 for manually setting a density value desired to be outside the original regardless of the background density of the original.

A sub-control unit 14 is connected to the main control unit 11 via a communication line 11a. This sub control unit 14
It centrally controls the processing of image signals photoelectrically converted by the CCD, and includes a CPU, a ROM that stores a control program that controls the scanner processing, a RAM that stores scanned image data, and the like. Composed.

Further, the main control unit 11 includes a communication line 1
The sub controller 15 is connected via 1b. The sub-control unit 15 controls, for example, the process of print output by a laser beam, and includes a CPU, a ROM storing a control program, and an R storing print data.
It is composed of AM and the like.

By the way, the aforementioned sub-control unit 14 includes a scanner processing unit 16 which optically scans a document and generates an image signal corresponding to an image on the scanned document, and a mechanism which optically scans the document. A scanner driving unit 17 for driving is connected. This scanner processing unit 16
Photoelectrically converts the reflected light reflected by the original by the CCD, and converts the analog image data into 8-bit image data.
After D / D conversion, one line of image data is stored in the line memory.
Processing for storing the data as a data. The scanner driving unit 17 performs a process of scanning the light source. Then, the scanner processing unit 16 outputs the image data for one line to the image processing unit 12 described above.

A print processing unit 18 and a print driving unit 19 are connected to the sub control unit 15 described above.
The print processing unit 18 executes a process of printing and outputting an image with a laser beam. The print drive unit 19 performs a process of driving various drive sources associated with the print output process.

Next, referring to FIG. 3, the structure of the in-frame area detection circuit of the image processing circuit will be described. Image data (8 bits) output in the scanner processing unit 16 described above.
Is input to a line memory 36 as a buffer in the scanner processing unit 16 and a background density determining unit 37 that determines the background density of the original from the image data. Base density determination unit 37
When the background density is determined by, the result is given to the RAM 38 as an address, and the threshold value Th (for example, “E0”) selected according to the background density is input from the RAM 38 to the binarization processing unit 31. Here, the background density determination unit 37 and the RAM 38 are controlled by the CPU 40 in the main control unit 11. The binarization processing unit 31 is used for the line memory 3
The 8-bit image data input from 6 is compared with an 8-bit threshold Th (for example, "E0"), and if image data ≧ threshold Th, binarized output "0", image data T <threshold T
If it is h, the binarized output "1" is output.

The binary signal output from the binarization processing unit 31 is output to the frame and nest level document detection processing unit 32. The frame and nest level document detection processing unit 32 is based on the principle of the frame area detection device disclosed in Japanese Patent Laid-Open Nos. 1-150546 and 3-17787.
The original frame represented by the value signal and the nest level are obtained. Then, the binary signal of the detected document frame and the document detection output at the nest level is output to the detection correction processing unit 33.

The principle of this frame area detection circuit will be described below with reference to FIGS. FIG. 5 is a diagram showing the result of binarization processing of multi-valued image data read by the CCD of the embodiment of the present invention in a frame area, and FIG.
FIGS. 7 and 8 are diagrams for explaining a method of level determination processing for performing binarized data under a constant condition, FIGS. 7 and 8 are diagrams showing the results of the above level determination processing for a framed area, and FIG. 9 is an embodiment of the present invention. FIG. 10 and FIG. 10 showing the image data for explaining the operation of the example are graphs showing the conversion table stored in the RAM for converting the background density information into the binarization threshold value.

The image data of the original range photoelectrically converted by the CCD is binarized by the binarization processing section 31.
The binarization process compares the image data with a threshold value for binarization, makes the following determination, and outputs a 1-bit result.

(1) Binarization threshold value (th)> Image data binarization output = 1 (2) Binarization threshold value (th) ≦ Image data binarization output = 0 Here, the binarization threshold value is In the automatic adjustment mode, it is determined in real time according to the background density, and in the manual mode, it can be arbitrarily set by inputting a threshold value from the operation panel 13 shown in FIG. That is, in the automatic adjustment mode, the background density information is RA as the address.
It is supplied to M38 and is preset to 0 according to the background density.
Predetermined threshold values from FF to FF are given from the RAM 38 to the binarization processing unit 31 in real time. Further, in the manual mode, when the threshold setting switch 25 of the operation panel 13 shown in FIG. 2 is pressed, the message display section 2 inquires about the background density desired to be outside the document, and the set density is input from the ten-key 21. The density data set by the CPU 40 is supplied to the RAM 38 as an address, and an arbitrary threshold value from 0 to FF is given from the RAM 38 to the binarization processing unit 31.

Generally, there is a range correction process as a process for outputting background density information as image processing, and this range correction process is executed by the background density determination unit 37. In this range correction processing, a reference value calculation processing is performed for each line to obtain a white reference and a black reference, and image density data input from the scanner unit is subjected to range correction calculation based on these respective references. In the automatic adjustment mode, the white reference obtained by this range correction processing is used as the background density information and an 8-bit signal
Is output to This background density information is output as density data that changes line by line. In the RAM 38, the binarization threshold value to be accessed is changed according to the change of the input background density information. This change in the binarization threshold is represented by a graph as shown in FIG. 10, and this is stored in the RAM 38 as a conversion table. Normally, this conversion table outputs a low binarization threshold when the background density is low as initial data, and outputs a high binarization threshold when the background density data is high. Furthermore, this conversion table can change the inclination and the like. For example, let's change it by calculating by the formula of y = ax + b. Here, the calculation is performed by changing the settings of the inclinations a and b.

In the automatic adjustment mode, a general background density setting value outside the original may be displayed.
By the process in the binarization processing unit 31 described above, binarized data corresponding to the background density for each line is obtained as shown in FIG. In FIG. 5, the thick originals A, B, and C placed on the original table 42 have irregular shapes, and the central printing surface portion 5 having a high image density is used.
2, 54, 56 and the margins 51, 5 surrounding them
3, 55 can be distinguished by the binarized data.

This processing is performed by the FF and 59 in FIG.
It is shown that the image data (first column) represented by, etc. is binarized (second column) by a threshold value. The original detection processing unit 32 detects the original from the binarized signal. This document detection processing uses the principle of level determination described in the patent specification of the in-frame area detection device that has already been applied for as described above.

A processing example and principle of this in-frame area level determination will be described with reference to FIG. This determination process is performed on documents A to C.
By detecting the frame portions 51, 53, 55 of the document (where the printing surface is not present in the document surface), the printing surfaces 52, 54, 56 are detected.
And the "ground" where the originals A to C on the original table 42 do not exist
It is carried out to distinguish it from the part of. When processing the distribution of binarized data as shown in FIG. 6, this processing is divided into four patterns assuming that this processing is advanced from the top of the screen. In other words, (1) As shown in Fig. 6 (a), the run of the current line is
The digitized output is 1) 62, and the adjacent front lines are all ground (2
If the digitized output is 0) 61; the level of the previous line is taken over. (2) As shown in Fig. 6 (b), the run of the current line is the ground (2
The digitized output is 0) 61, and the adjacent front lines are all frame (2
If the digitized output is 1) 62; add 1 to the level of the previous line.

(3) When the run of the current line is the frame (binarized output is 1) 62 as shown in FIG. 6C, and the adjacent front line has both the ground 61 and the frame 62; Inherit the minimum level of the line frame.

(4) As shown in FIG. 6 (d), when the run of the current line is the ground (binarization output is 0) 61, and the adjacent front line includes both the ground 61 and the frame 62; Inherit the minimum value of the ground level of the line.

By applying the above processing to the data of FIG. 5, the pixel level distribution after the level determination processing shown in FIG. 7 can be obtained. Further, the output of the document detection process is determined by the following process based on the result of the area determination within the frame (FIG. 7) and the binarized output (FIG. 6), and the 1-bit result (FIG. 8)
Is output.

(1) Binarized output = 1 or level of level determination result other than 0 Original detection output = 1 (2) In cases other than the above, original detection output = 0 As a result of such processing, in FIG. In the binarized data of No. 2, the print surfaces 52, 54, 56 of the originals A to C and the ground portion 42, which cannot be distinguished by "0", are indicated by "1" in the original surface and "0" in FIG. It is possible to clearly distinguish "" as the ground part.

The document detection process is shown by the document detection output on the third line in FIG. The data of the document detection process 32 is corrected by the detection correction processing unit 33 to remove noise in a minute area. In the processing unit 33, the binary signal output from the document detection processing unit 32 starts at the pixel of "1", the pixel counts up by 1 by the connection of 1 pixel, and the pixel of "1" becomes "0". Using a counter (fourth column in FIG. 9) that clears the counter to 0 at the pixel changed to the pixel and a register (fifth column in FIG. 9) in which the correction width (3 in the example) is set The following processing is performed and a 1-bit result is output.

(1) At the start position of the original area in the main scanning direction (change point from pixel 0 to pixel 1), the correction width is subtracted from the count value (by comparing the counter value with the correction width). It is obtained by replacing the pixels up to 0.

(2) The end position of the original area in the main scanning direction (the change point from the pixel of 1 to the pixel of 0) is obtained by replacing 0 from the pixel obtained by subtracting the correction width from the count value.

The state of this processing is shown by the processing between the counter value (fourth row) and the detection correction output (fifth row) in FIG. In other words, now, due to the minute dust (61 in FIG. 9),
The counter value (fourth line) is counted from 1 to 6 in the area where the original detection output is "1" even though there is no original. The detection width is set to 3 by this detection correction processing. If so, 3 from the right and 3 from the left are "
1 ”is replaced with“ 0 ”. As a result, in the detection correction output (fifth line), all the data corresponding to this dust is“ 0 ”, and therefore the final out-of-document erase output is also dust 61.
Data is "00", and unlike the conventional case, the phenomenon of black copying does not occur even though there is no original paper.

Here, as the correction width, the set parameter value is set in the register of the detection correction processing section 35 by the CPU 40 before the start of copying as described above. The outside-original erasure processing unit 34 takes in the binary signal output from the detection correction processing unit 33 and the image data input to the above-described binarized signal via the delay circuit (D) 35, and (1) When the detection correction processing output = 1, the original image data is output.

(2) When the detection correction processing output = 0, it is replaced with white (00). This result is shown by the out-of-original erasure output (sixth line) in FIG. 9, and the output of a portion where the thick originals A to C do not exist or the output of a minute portion such as dust is "
It is 00 ", and it can be seen that the image is not copied in black.

Next, the external structure of the digital copying machine will be briefly described with reference to FIG. In FIG. 4, 41
Is a copying machine main body, 42 is a document table disposed on the upper surface of the copying machine main body 41, and 43 is a platen cover. Opening / closing of the platen cover 43 is detected by an opening / closing switch (not shown), and the detection signal is output to the main control unit 11 described above.

Next, the operation of the image forming apparatus of the present invention configured as above will be described. First, the thick original to be copied is placed on the original table 42, and the printing key 23 is pressed with the platen cover 43 not completely closed. The main control unit 11 takes in a detection signal of an open / close switch (not shown) of the main operation panel unit 13, the main control unit 11 detects that the platen cover 43 is open, and sets the processing parameters already set. Using the flow chart of FIG.
The external document removal process shown in FIG. As a matter of course, when the platen cover is completely closed, the outside document erasure processing mode is cleared to the normal mode.

When the processing parameter is changed to execute the extra-original removal processing, the processing parameter is changed by inputting the following to the operation panel unit 13. When an out-of-original erasure mode switch (not shown) on the operation panel section 13 is pressed, the message display section 22 is displayed as shown in FIG. Here, the correction width (16 in the illustrated example) is input by using the ten-key pad 21, and is fixed by the print key 23. Next, as shown in FIG. 12, the message display section 22 displays “Sentence (1: Yes, 0: N
o) ”is displayed, enter whether it is a full-face process (No = 0 in the example shown in the figure) and confirm with the print key 23. After that, the thick document is set on the platen 42 and the print key is pressed. By pressing 23, the outside-original removal processing shown in the flowchart of FIG. 13 is executed using the processing parameters changed as described above.

Further, when executing the manual mode for manually selecting the binarization threshold value instead of the automatic adjustment mode in which the binarization threshold value is automatically selected, the threshold value setting switch of the operation panel 13 shown in FIG. 2 is used. When the user presses 25, the message display section 2 asks about the background density desired outside the document, and when the set density is entered from the ten-key pad 21, the CPU 4
The density data set from 0 is used as an address in the RAM 3
8 and the arbitrary threshold value from 0 to FF is stored in the RAM 38.
Is given to the binarization processing unit 31, and the image data is binarized by the set binarization threshold value.

As shown in FIG. 13, the outside document erasure process (S
In 1), make sure that the platen cover is open (S2), and if it is open, binarize it with the threshold value (S2).
3) The document detection process (S4) is performed. Further, the minute area is erased (S5), and the image data outside the original of the original data is replaced with "00" (S6). The platen cover
If it is closed, the erasure process outside the document is not performed.

The main control unit 11 communicates to the sub control units 14 and 15 that the print key 23 of the operation panel unit 13 has been operated. Then, the scanner driving unit 17 and the scanner processing unit 16 are driven. That is, the scanner processing unit 16
The reflected light reflected by the original is photoelectrically converted by a CCD to convert the analog image data into 8-bit image data, which is then stored in the line memory 36 as one line of image data. At the same time, the background density determining unit 37 determines the background density of one line from the image data. And
The scanner processing unit 16 outputs the image data for one line to the image processing unit 12, and outputs the binarization threshold value corresponding to the one line from the RAM 38 according to the density information from the background density determination unit 37. To be done.

The image data (8 bits) output from the scanner processing unit 16 described above is input to the binarization processing unit 31 of the image processing unit 12. The binarization processing unit 31 compares the input 8-bit image data with the 8-bit threshold Th (for example, “E0”) supplied from the RAM 38, and if the image data ≧ threshold Th. For example, binary output “0”,
If image data <threshold value Th, "1" is output as the binarized output (see the second column in FIGS. 5 and 9).

The binary signal output from the binarization processing unit 31 is output to the frame and nest level document detection processing unit 32. The frame and nest level document detection processing unit 32 is based on the principle of the frame inner area detection device disclosed in Japanese Patent Laid-Open No. 3-17787, and is a binary signal of the document frame and nest level document detection output (FIG. 8). , The third column in FIG. 9) is output to the detection correction processing unit 33. Here, the binary signal output from the document detection processing unit 32 starts at the pixel of “1”, and is incremented by 1 by the connection of 1 pixel,
The following processing is performed using the counter that clears the counter to 0 and the register that sets the correction width (3 in the example) at the pixel that has changed from the "1" pixel to the "0" pixel, and the 1-bit result is obtained. It is output as the detection correction output (fifth column) shown in FIG.

(1) The start position of the original area in the main scanning direction (the change point from the pixel of 0 to the pixel of 1) is obtained by replacing 0 from the count value to the pixel subtracted from the correction width.

(2) The end position of the original area in the main scanning direction (the change point from the pixel of 1 to the pixel of 0) is obtained by replacing 0 from the count value to the pixel minus the correction width.

Further, the count value of the counter is cleared to 0. Then, the extra-original erasure processing unit 34 takes in the binary signal output from the detection correction processing unit 33 and the image data input to the above-mentioned binarized signal through the delay circuit 35 and performs the following processing. , And outputs the signal shown in FIG.

(1) When the detection correction processing output = 1, the original image data is output. (2) When the detection correction processing output = 0, it is replaced with white (00). In this manner, the image forming apparatus of the present invention can print the thick original with the outside of the original white, and can also print a white area up to a minute area having a width twice the correction width.

Here, FIG. 14 is a diagram showing a copying state when copying is performed by the apparatus of the embodiment, and FIGS. 15 (a) and 15 (b).
FIG. 8 is a diagram showing a copy example of a document when a thick document is copied by an apparatus to which the present invention is not applied. That is, according to the image forming apparatus of the present invention, the same thick original “AAA”,
When "BBB", "CCC" and the minute area "a" are placed on the platen for copying, as shown in FIG.
Parts other than "A", "BBB", and "CCC" can be printed in white.

Further, in the image forming apparatus of the present invention, the image processing described in the above description of the operation is performed in the main scanning direction and the sub-scanning direction as shown in FIG. 5, FIG. 7 and FIG. It is running both in the scan direction. Therefore, as shown in FIG. 16, the black portion b generated when the outside of the original is erased only in the main scanning direction is subjected to the above image processing also in the sub scanning direction according to the embodiment of the present invention. Therefore, it is possible to erase outside the original even between the two thick originals b.
Copying is possible without the black areas shown in Fig. 14.

Further, in the processing method according to the embodiment of the present invention, the binarization processing unit 31 sets 1 according to the background density of the original.
The binarization threshold value is changed and input for each line. Therefore,
According to the conventional processing method, for an original having a high background density such as a newspaper as shown in FIG. 17A, a high density black background portion 81 outside the original is provided as shown in FIG. 17B. Not only the part 83 of the original portion 82 having a high background density is erased and printed, but in the processing method according to the embodiment of the present invention, the high portion outside the original is printed as shown in FIG. 17 (c). Only the black background portion 81 having a high density is erased, and the original portion 82 having a high background density can be printed as it is. Further, in the conventional processing method, when there is a part where the document floats on a thick book as shown in FIG. 18A, the background density of the part where the document floats becomes high, Figure 1
As shown in 8 (b), not only the original portions 86 and 87 but also the floating portion 84 of the original may be printed.
In the processing method according to the embodiment of the present invention, the floating portions of the original are erased as shown in FIG.
Only 7 can be printed.

Although the detection correction processing unit 33 is provided after the frame and nest level original document detection processing unit 32 in the above embodiment, the frame and nest level original document detection processing unit 32 is provided unless it is necessary to delete the minute area a. The detection output of the above may be directly output to the outside-original erasure processing unit 34.

As a modification of the above embodiment, the platen cover 43 indicates that a thick original is placed on the original table 42.
The open / close switch 44 (FIG. 4) for detecting the open / close state of the document is used for detection.
It is also possible to start the processing of the flowchart of FIG. 10 by the operation from 4.

[0055]

As described above in detail, according to the image forming apparatus of the present invention, the binary information is binarized in real time by the binarization threshold conversion table by using the external information such as the background density information of the original obtained by the image processing. The conversion threshold can be changed, and it is possible to automatically process both the original document whose intermediate density portion is desired to be the original document and the original document whose intermediate density portion is desired to be the original document as desired.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a digital copying machine according to an embodiment of the present invention.

FIG. 2 is a plan view of an operation panel unit according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a main part of an image processing unit according to an embodiment of the present invention.

FIG. 4 shows a perspective view of a digital copying machine according to an embodiment of the present invention.

FIG. 5 is a diagram showing a result of binarization processing of multi-valued image data read by the CCD according to the embodiment of the present invention in an area within a frame.

FIG. 6 is a diagram illustrating a method of level determination processing for performing the binarized data under a constant condition.

FIG. 7 is a diagram showing a result of the above level determination processing on a frame area.

FIG. 8 is a diagram showing a result of a framed region obtained from a level determination processing result and a binarization processing result.

FIG. 9 is a diagram showing image data for explaining the operation of the embodiment of the present invention.

FIG. 10 shows that the binarization processing circuit has two values depending on the background density value information.
It is a graph which shows an example of the conversion table which supplies a threshold value.

FIG. 11 is a plan view showing the display contents of the operation panel unit.

FIG. 12 is a plan view showing the display contents of the operation panel unit.

FIG. 13 is a flowchart for explaining the operation of the embodiment of the present invention.

FIG. 14 is a diagram showing a copying state when copying is performed by the apparatus according to the embodiment of the present invention.

FIG. 15 is a diagram showing a copy example of a document when a thick document is copied by an apparatus to which the present invention is not applied.

FIG. 16 is a diagram showing a copy example of a document when a thick document is copied by an apparatus to which the present invention is not applied.

FIG. 17 is a diagram showing a copying state when copying is performed by the apparatus of the embodiment of the present invention and a diagram showing an example of copying an original when a thick original is copied by an apparatus to which the present invention is not applied.

FIG. 18 is a diagram showing a copying state when copying is performed by the apparatus of the embodiment of the present invention and a diagram showing an example of copying an original when a thick original is copied by an apparatus to which the present invention is not applied.

[Explanation of symbols]

 11. ． ． Main control unit 12. ． ． Image processing unit 13. ． ． Operation panel section 16. ． ． Scanner processing unit 31. ． ． Binarization processing unit 32. ． ． Document detection unit 33. ． ． Detection / correction processing unit 34. ． ． Outside document erasure processing unit 36. ． ． Line memory 37. ． ． Base density determination unit 38. ． ． RAM 40. ． ． CPU 42. ． ． Manuscript table

Claims (4)

[Claims] 1. A conversion means for converting an image having an original area and an area outside the original into an image signal, and a background density corresponding to a background outside the original area and the area outside the original is determined from the image signal to obtain a background density signal. A background density determining means to be generated, a reference signal generating means to generate a reference signal according to the background density, and a binarization generating means to compare the reference value and the image signal to generate a binarized signal, Out-of-original detection means for calculating the distribution of this binarized signal to detect an out-of-original area to detect an out-of-original detection signal, and an out-of-original signal corresponding to the outside of the original from the image signal by referring to the out-of-original detection signal. An image forming apparatus comprising: an extra-original erasing means for erasing a component; and an image forming means for forming an image based on an image signal from which the extra-original signal component has been removed. 2. An input for externally inputting a background density corresponding to an arbitrary background to a reference signal generating means to generate a background density signal, and generating a reference signal from the reference signal generating means with the input background density signal. The image forming apparatus according to claim 1, further comprising means. 3. An image having an original area and an area outside the original is
A conversion unit for converting each line to generate a 1-line image signal, and a background density corresponding to the background outside the original area and the area outside the original is determined from the 1-line image signal to determine the background density according to the 1-line image signal. A background density determining means for generating a signal, a reference signal generating means for generating a reference signal according to the background density, and a binarization generating means for comparing a reference value and an image signal to generate a binarized signal. Out-of-original detection means for calculating the distribution of the binarized signal to detect the out-of-original area of the one-line image and generating an out-of-original detection signal; The image forming apparatus further comprises: an extra-original erasing means for erasing an extra-original signal component outside the original; and an image forming means for forming an image based on the one-line image signal from which the extra-original signal component has been removed. Image forming apparatus. 4. A conversion unit for converting an image having an original area and an area outside the original into an image signal, and a background density corresponding to a background outside the original area and the area outside the original is determined from the image signal to obtain a background density signal. A background density determining means to be generated, a reference signal generating means to generate a reference signal according to the background density, and a binarization generating means to compare the reference value and the image signal to generate a binarized signal, Out-of-original detection means for calculating the distribution of the binarized signal to detect an out-of-original area to generate an out-of-original detection signal, and one level of the binarized signal is continuously generated exceeding a predetermined number. If the predetermined number is not exceeded, a correction means for generating a correction signal for correcting the binarized signal, and an out-of-original signal corresponding to the out-of-original signal from the image signal by referring to the out-of-original detection signal The component is erased and the image is displayed in response to the correction signal. An image forming apparatus characterized by comprising the outside of the document erasure means for correcting the signal, and an image forming means for forming an image based on an image signal outside the original signal components have been removed.