JPH07170405A - Document edge shadow signal removal method, image signal processing apparatus, and copier - Google Patents

Abstract

(57) [Abstract] [Purpose] In a copying machine that copies a document written on paper, etc., it is possible to prevent the shadow of the edge of the document that is not originally an image signal from being copied as an image, and to use only the original document image. To obtain a high quality copied image. An edge signal detector 21 detects a shadow signal of an edge of a document from an image signal obtained by reading a document image 1 with an image signal reading device 2, and the detected shadow signal of an edge of the document. Is removed from the image signal by the edge signal remover 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color and monochrome copying machine for copying an original written on paper or the like, and more particularly to detecting an edge shadow signal of an original and forming an image of the edge shadow signal. The present invention relates to a method for removing an edge shadow signal of an original for removing a high-quality copied image from a signal, an image signal processing device and a copying machine using this removal method.

[0002]

2. Description of the Related Art FIG. 11 is a block diagram showing the flow of image signals in a conventional copying machine. In the figure, 1 is an original image to be copied, and 5 is a copied image obtained by copying.
The image signal reading device 2 reads the original image 1 and outputs the image signal to the image signal processing circuit 3. The image signal processing circuit 3 performs signal processing on the input image signal and outputs the processed image signal to the image signal printing device 4. The image signal printing device 4 prints the input image signal on a copy sheet to obtain a copy image 5.

Next, the operation will be described. The original image 1 is converted into a digital electric signal by the image reading device 2 and input to the image signal processing circuit 3. In the image signal processing circuit 3, the density, hue, etc. of the original image is reproduced in the copied image 5 faithfully to the original image 1 in response to the input image signal, or the user operates the density, hue adjustment buttons, etc. In order to obtain a copy image 5 of the specified density and color,
Further, various signal processing is performed so that a copy image 5 obtained by enlarging or reducing the original image 1 at a scale desired by the user can be obtained. The image signal processed by the image signal processing circuit 3 is input to the image signal printing device 4, and the processed image signal is printed by the image signal printing device 4 to obtain the copied image 5 desired by the user.

[0004]

Since the conventional copying machine is constructed as described above, it is possible to obtain a copied image that is faithful to the original image, but when copying an original written on paper or the like, There is a problem in that the periphery of the paper or the like of the document or the periphery of the paper or the like pasted on the document becomes a black shadow and appears as an image signal in the copy image, and the image quality of the copy image is deteriorated. There is. In particular, when the image signal processing circuit 3 performs signal processing so that the density of the copied image becomes high, for example, when the user sets the density of the copied image to be high, the density of the shadow of the edge of the original paper or the like is also increased. It is emphasized and printed.

In many cases, the copy image is not printed until the edge of the copy sheet is almost reached.
The non-printing area is from mm to several cm. Therefore, when the original paper and the copy paper have the same size, an image close to the edge of the original may not be printed. In order to print the entire image of the original, it is only necessary to reduce it by a few percent before copying, and a copier that has a reduction setting button such as "98% mode" so that the user can easily perform this reduction work. There is also. When such reduction is performed, it is likely that the shadow around the document is black and the image is copied so as to surround the periphery of the copied image. Even if the entire document image can be printed, the image quality is not good.

The present invention has been made in view of such circumstances, and when copying an original written on a paper or the like, the shadow of the edge of the paper or the like of the original does not appear in the copied image, and the high quality image is obtained. An object of the present invention is to provide a document edge shadow signal removing method capable of obtaining a copied image, an image signal processing apparatus and a copying machine using the removing method.

Another object of the present invention is to provide a document edge shadow signal removal method which can be handled at a lower cost because a memory such as a page memory is not used, and an image signal processing apparatus and a copying machine using this removal method. Especially.

[0008]

A method of removing an edge shadow signal of an original according to a first aspect of the present invention detects and detects a signal of an edge shadow of an original based on a density value from an image signal obtained from the original. The feature is that the signal of the shadow of the edge is removed from the image signal.

A method of removing an edge shadow signal of an original according to a second aspect of the present invention is a shadow of an edge of an original which is pasted from an image signal obtained from another original pasted on the original. When the edge shadow signal is detected and the edge shadow signal is detected, the edge shadow signal is removed by using the peripheral image signal which is not the edge shadow signal.

A document edge shadow signal removing method according to a third aspect of the present invention detects a signal of a shadow of an edge of a document from an image signal obtained from the document, and detects the input image signal and the signal of the shadow of the edge. The feature is that the signal of the shadow of the edge is removed by obtaining the difference.

The image signal processing apparatus according to the fourth aspect of the present invention is a detecting means for detecting an image signal having a density equal to or lower than a predetermined density as an edge shadow signal of an original from the image signals obtained from the original, and the detected edge. And a removing means for removing the shadow signal from the image signal.

In the image signal processing device according to the fifth invention of the present application, in the fourth invention, when the detecting means detects the signal of the shadow of the edge of the document, the image signal processing device outputs a detection signal to that effect to the removing means. It is characterized in that it is configured in.

An image signal processing apparatus according to the sixth invention of the present application comprises a storage means for storing an image signal obtained from a document,
The image signal read out from the storage means, the detecting means detecting the shadow signal of the edge of the document based on the density value, and the removing means for removing the detected shadow signal of the edge from the image signal. To do.

An image signal processing device according to a seventh aspect of the present invention comprises a storage means for storing an image signal obtained from a document.
From the image signal read out from the storage means, a detection means for detecting the shadow signal of the edge of the document based on the density value, a storage means for storing the shadow signal of the detected edge, and a detected shadow signal of the edge are stored. And removing means for removing from the image signal.

An image signal processing device according to an eighth invention of the present application is the image signal processing device according to any one of the fourth to seventh inventions, which is intended for a document in which a second document portion is pasted on a first document portion, and a shadow of an edge of the second document portion. Is detected.

An image signal processing apparatus according to the ninth invention of the present application detects an image signal having a density equal to or lower than a predetermined density existing in a predetermined area of an original from among image signals obtained from the original as a signal of a shadow of an edge of the original. And a removing unit that removes the detected edge shadow signal from the image signal.

The copying machine according to the tenth aspect of the present invention detects a reading means for reading an image of a document to obtain an image signal, and a detecting means for detecting a signal of a shadow of an edge of the document from the obtained image signal. Removal means for removing the edge shadow signal from the image signal, signal processing means for performing signal processing for printing the image signal from which the edge shadow signal has been removed, and printing means for printing the processed image signal. And is provided.

[0018]

According to the first aspect of the invention, the shadow signal of the edge of the original which is not the original image signal is detected from the image signals read from the original image, and the detected shadow signal of the edge is converted into the image signal. To obtain an image signal from only the original document image.

According to the second aspect of the invention, among the image signals read from a document in which another document is pasted onto the document, the edge of the pasted document which is not the original image signal is detected. By detecting the shadow signal and outputting the image signal around the detected edge shadow signal, the edge shadow signal is removed from the image signal to obtain an image signal only from the original document image.

According to the third aspect of the present invention, the signal of the shadow of the edge of the document which is not the original image signal is detected from the image signals read from the image of the document, and the signal of the shadow of the detected edge is input to the input image. The signal of the shadow of the edge is removed from the image signal by subtraction from the signal to obtain the image signal from only the original document image.

According to the fourth aspect of the invention, the detecting means detects the signal of the shadow of the edge of the document which is incorrectly input as an image from the image signals read from the document image, though it is not originally the image signal. , Based on the density value, it is detected as a signal different from the original image signal, and the removing means removes the detected shadow signal of the edge from the image signal to obtain an image signal from only the original document image. obtain.

According to the fifth aspect of the invention, when the signal of the shadow of the edge of the document is detected, the detecting means outputs the detection signal notifying the fact to the removing means, and the removing means produces the shadow of the edge in accordance with the detection signal. The signal is removed from the image signal.

In the sixth aspect of the invention, the storage means stores the image signal read from the original image, the detection means reads the image signal from the storage means, and based on the density value, it is not the original image signal. The signal of the shadow of the edge of the original that is erroneously input as an image is detected as a signal different from the original image signal, and the removing unit removes the detected signal of the shadow of the edge from the image signal. , Obtain an image signal from only the original document image.

In the seventh aspect of the invention, the storage means stores the image signal read from the original image, the detection means reads the image signal from the storage means, and based on the density value, it is not the original image signal. The signal of the shadow of the edge of the document that is erroneously input as an image is detected as a signal different from the original image signal, and the storage unit stores the detected signal of the shadow of the edge, and the removal unit Then, the detected edge shadow signal is removed from the image signal to obtain an image signal from only the original document image.

According to the eighth aspect of the invention, even in the case where another original is pasted on the original, the shadow signal of the edge of the pasted original is detected and the detected edge is detected. The shadow signal of is removed from the image signal.

According to the ninth aspect of the invention, the detecting means detects, from the image signals read from the image of the original, a signal of the shadow of the edge of the original which is not the original image signal but is erroneously input as the image. , Based on the density value in a predetermined area of the document, detected as a signal different from the original image signal,
The removing means removes the detected shadow signal of the edge from the image signal to obtain an image signal from only the original document image.

According to the tenth aspect of the invention, the signal of the shadow of the edge of the original document which is not the image signal originally but is erroneously input as the image is detected, and the detected signal of the shadow of the edge is detected from the image signal. After removal, an image signal from only the original document image is obtained. Therefore, when the original image is copied, the shadow of the edge of the original does not appear in the copied image, and a high-quality copied image consisting of only the original image can be obtained.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments.

Embodiment 1 FIG. 1 is a block diagram showing the flow of image signals in a copying machine according to an embodiment of the present invention. In FIG. 1, 1
Is an original image, 2 is an image signal reading device for reading the original image, 3 is an image signal processing circuit for performing signal processing on the image signal, 4 is an image signal printing device for printing the image signal on a copy sheet, and 5 is a copy image to be obtained. Since these are the same as those in the conventional example shown in FIG. 11, description thereof will be omitted. The image signal reading device 2 outputs the read image signal to the page memory 20.
Output to. The page memory 20 is a page memory capable of storing all image signals on one input document. The stored image signal data is read from the page memory 20 to the edge signal detector 21 one by one.
The edge signal detector 21 determines whether or not the read image signal data is a signal of a shadow of an edge of the paper of the document (hereinafter referred to as an edge signal), that is, an edge signal is detected from the image signal. The edge signal data is stored in the edge signal storage memory 22.

Next, the operation will be described. 2 and 3
6 is a flowchart showing an operation procedure of edge signal detection in the first embodiment. The original image 1 is an image reading device 2
Is read by, converted into a digital electric signal, and input to the page memory 20. When the reading of all the image signals on the original document and the storage in the page memory 20 are completed, the image signal data in the page memory 20 is input to the edge signal detector 21 one by one (step S1) to generate an edge signal. I will check whether or not. The criteria for checking are some properties characteristic of edge signals.
The characteristic points of the edge signal are the following three points. (1) The shadow of the edge is black and has low density. (2) The shadow of an edge is a thin continuous line. (3) There is no image data in the part of the document that is outside the edge. The edge signal detector 21 checks whether there is continuous data that satisfies the above points. The details will be described below.

(1) The shadow of the edge is black and has low density. Since the shadow of an edge has a considerably lower density than that of a normal image signal, only data having a certain density level or lower is a candidate for an edge signal. Since the shadow of the edge appears black, in the case of a color copying machine, only the image signal having black color information is detected. A density that can be determined as an edge signal is set in the edge signal detector 21 in advance, and an image signal having black color information equal to or lower than the set density is detected as an edge candidate signal (step S2). The edge candidate signal is an edge signal storage memory 22 for storing the data of the edge signal.
Is stored in (step S3). The above check is performed for all the image signal data stored in the page memory 20 (step S4).

(2) The shadow of the edge is a thin continuous straight line. Next, from among the edge candidate signals stored in the edge signal storage memory 22, signals that are candidates for edge signals are further narrowed down. The shadow of the edge appears as a thin straight line, so 1
In the edge signal, there should be adjacent edge signals that are continuous with almost the same density. Therefore, when there is no continuous edge candidate signal in a certain density range in a certain one edge candidate signal, the edge candidate signal is not an edge signal. Also,
One edge signal should be continuous in only one direction. Therefore, a signal which is continuous in all directions and a plurality of directions or a signal whose continuous direction is not constant in a certain density range is not an edge signal. Based on these detection criteria, the edge candidate signal data stored in the edge signal storage memory 22 is input to the edge signal detector 21 one by one (step S5), and it is checked whether or not it is an edge signal ( Step S
6). When detected as an edge candidate signal, it is returned to the edge signal storage memory 22 again (step S7), and when judged as an image signal which is not an edge candidate signal, the data is erased from the edge signal storage memory 22 (step S13). The above check is performed on all the data stored in the edge signal storage memory 22 (step S8).

(3) There is no image data in the portion of the document that lies outside the edge. In addition, the area outside the edge of the original paper is usually
Since the image signal cannot exist, if the image signal or the edge candidate signal exists at a position outside the document than the position where the edge candidate signal obtained by the checks of (1) and (2) exists, the The edge candidate signal is not the edge signal but the original image signal. Therefore, the edge candidate signal is again input from the edge signal storage memory 22 to the edge signal detector 21 one data at a time (step S9), and it is checked whether or not it is an edge signal (step S1).
0). When it is detected as an edge candidate signal, it is returned to the edge signal storage memory 22 again (step S11), and when it is judged as an image signal which is not an edge candidate signal, the data is erased from the edge signal storage memory 22 (step S13). The above check is performed on all the data stored in the edge signal storage memory 22 (step S12).

As described above, the edge signal detector 21 detects the edge signal from the image signal stored in the page memory 20.
To detect. When the detection is completed, only the edge signal satisfying the above conditions is stored in the edge signal storage memory 22. After the edge signal detection is completed, the image signal is input from the page memory 20 to the image signal processing circuit 3 and subjected to various signal processing for printing. The image signal processed by the image signal processing circuit 3 is input to the image signal printing device 4, and the copied image 5 desired by the user is obtained.

Embodiment 2 In this Embodiment 2, when a manuscript written on paper or the like is pasted with glue or the like, the manuscript is copied onto the manuscript, etc. In this embodiment, the shadow signal (edge signal) of the edge is detected from the image signal. The flow of the image signal in the copying machine for carrying out the second embodiment is as follows.
This is the same as the first embodiment shown in FIG.

Next, the operation will be described. Original image 1
Is read by the image reading device 2, converted into a digital electric signal, and input to the page memory 20. When all the image signals on the original are read and stored in the page memory 21, the image signal data in the page memory 21 are input to the edge signal detector 21 one by one as in the first embodiment. I will check whether or not. The criteria for checking are some properties characteristic of edge signals. The characteristic points of the edge signal of the paper or the like attached on the original are the following two points. (1) The shadow of the edge is black and has low density. (2) The shadow of an edge is a thin continuous line.

The edge signal detector 21 checks whether there is continuous data that satisfies the above points. Since the procedure of this check is the same as (1) and (2) of the first embodiment, its description is omitted. Then, similarly to the first embodiment, when the detection is completed, only the edge signal satisfying the above condition is stored in the edge signal storage memory 22. Since the operation after the check is the same as that of the first embodiment, the description is omitted.

By the way, in the process of detecting the edge signal of the original written on the paper or the like described in the first embodiment, the edge signal of the paper stuck on the original described in the second embodiment is detected. Therefore, when it is desired to simultaneously detect the shadow of the edge of the document and the shadow of the edge of the paper pasted on the document, the first embodiment and the second embodiment may be combined.

Embodiment 3 A method of detecting an outermost edge signal of an original written on paper or the like in Embodiment 1 by using a page memory will be described as Embodiment 2.
In the above, the method of detecting the edge signal of the paper or the like attached to the area within the original on the original by using the page memory has been described, but the use of the page memory causes a problem of high cost. In the third embodiment, the edge signal is detected from the image signal without using a memory such as a page memory.

FIG. 4 is a block diagram showing the flow of image signals in the copying machine according to the embodiment of the present invention. Figure 4
In FIG. 1, the parts given the same numbers as in FIG. 1 indicate the same or corresponding parts, and therefore their explanations are omitted. FIG. 5 is a flowchart showing the operation procedure of edge signal detection in the third embodiment.

Since the edge signal has a considerably lower density than a normal image signal, it is possible to detect an image signal having a certain density level or less as an edge signal. Also,
Since an edge signal has black color information, in a color copying machine, only an image signal having black color information is targeted for edge signal detection.

The original image 1 is read by the image signal reading device 2, converted into a digital electric signal, and input to the edge signal detector 21 (step S21). The edge signal detector 21 is set in advance with a density that can be judged as the shadow of the edge of the original written on the paper or the like and the shadow of the edge of the paper or the like pasted on the original written on the paper with glue or the like. Then, it is determined whether or not the density is equal to or lower than the set density (step S22), and an image signal having a predetermined density or less, which has black color information, among the input image signals is detected as an edge signal (step S23).
The operation after the edge signal detection is the same as that in the first embodiment.

By doing so, it is possible to easily and inexpensively detect an edge signal which is black and whose density is considerably lower than that of the image signal.

Fourth Embodiment In the third embodiment, the method of simply detecting the edge signal has been described, but in the case where the original is limited to a certain size in a copying machine for copying an original written on a paper or the like. ,
It is possible to detect the edge signal of the document more reliably. This method will be described below as Example 4. In addition,
The flow of the image signal in the copying machine for carrying out the fourth embodiment is the same as that of the third embodiment shown in FIG.

As described above, the copied image is often not printed until the edge of the copy sheet is reached. Usually, the peripheral portion of the paper of several mm to several cm is the non-printed area. Therefore, the original paper and the copy sheet are not printed. When and have the same size, a reduction setting button such as "98% mode" is provided in order to print all the original images. In most cases, the user specifies "98% mode" etc. for a certain standard document size, and this is the most common case where the shadow of the edge of the document paper is copied by a copying machine. To be here,
The fact that the document size is constant means that the position where the shadow of the edge of the document appears is constant.
Therefore, it can be said that a signal whose density is lower than a certain level of black color in a certain area is almost certainly an edge signal.

The image signal read from the original image 1 by the image signal reading device 2 and converted into a digital electric signal is input to the edge signal detector 21. The edge signal detector 21 is set in advance with the density that can be judged as the shadow of the edge of the original written on a paper or the like and the area in which the edge signal appears, and the edge of the image signal input to the edge signal detector 21 An image signal within the signal area and having a density equal to or lower than the set density is detected as an edge signal. At the time of edge detection, when the copying machine is a color copying machine, only the image signal having black color information is targeted for edge signal detection. The operation after the edge signal detection is the same as that in the first embodiment.

Even in the case of a copying machine which does not have a setting button for "98% mode", etc., the edge signal detector is assumed assuming the paper size of the original document defined by JIS standards. By setting the range in which the edge signal appears in 21, the edge signal of the document can be detected.

Embodiment 5 FIG. 6 is a block diagram showing the flow of image signals in a copying machine according to an embodiment of the present invention. In FIG. 6, the parts given the same numbers as in FIG. 1 indicate the same or corresponding parts, and therefore their explanations are omitted. Reference numeral 50 in FIG. 6 denotes an edge signal remover for removing the edge signal detected by the edge signal detector 21 from the image signal.

In the fifth embodiment, as described in the second embodiment, the edge signal detector detects the edge signal of the paper pasted on the original such as the paper from the image signal by using the page memory 20 with glue or the like. After the detection at 21, the detected edge signal is further removed from the image signal.

Next, the operation will be described. FIG. 7 is a flowchart showing the operation procedure of edge signal removal in the fifth embodiment. Image signal reading device 2 from original image 1
The image signal read by and converted into a digital electric signal is input and stored in the page memory 20. The image signal is input from the page memory 20 to the edge signal detector 21, an edge signal is detected from the image signal (step S31), and the detected edge signal is stored in the edge signal storage memory 22. The detection operation of the edge signal at this time is the same as that in the second embodiment. After the detection of the edge signals of all the image signals on the document is completed, the image signals from the page memory 20 are input to the edge signal remover 50 (step S31). The edge signal remover 50 sequentially checks whether or not the input image signal is stored in the edge signal storage memory 22 (step S33), and if a certain image signal is not an edge signal, outputs the image signal as it is. (Step S35), if an image signal is the edge signal stored in the edge signal storage memory 22, the edge signal is not output, and the image signal around the edge signal is read from the page memory 20. Instead, it outputs (step S34). Edge signal remover 50
The signal output from is input to the signal processing circuit 3. The subsequent operation is the same as that of the first embodiment, and thus the description thereof is omitted.

The image signal around the edge signal is an image signal located next to the position where the edge signal exists, such as in the front, rear, left and right, and if the shadow of the document is not input as the image signal, it is originally located at that position. It is an image signal that is continuous and most similar to the existing image signal. The edge signal remover 50 is set in advance as to which position of the peripheral signal is to be read instead of the edge signal, and the image signal is read from the page memory 20 and output instead of the edge signal. If the read image signal is an edge signal, the image signal at another position is read again.

As described above, by using the peripheral signal instead of the edge signal, it is possible to obtain an image signal having no edge signal. As a result, it is possible to obtain a high quality copied image 5 of only the original image.

Sixth Embodiment In the fifth embodiment described above, the case where the edge signal detected in the second embodiment is removed has been described. In the sixth embodiment, the shadow signal of the edge of the document according to the first embodiment is detected as the edge signal. In this case, the detected edge signal is removed. The flow of the image signal in the copying machine implementing the sixth embodiment is the same as that of the fifth embodiment shown in FIG. FIG. 8 is a flowchart showing the operation procedure of edge signal removal in the sixth embodiment.

The image signal read from the original image 1 by the image signal reading device 2 and converted into a digital electric signal is input and stored in the page memory 20. According to the procedure of the first embodiment, the image signal stored in the page memory 20 is input to the edge signal detector 21 to detect the edge signal (step S41), and the detected edge signal is stored in the edge signal storage memory 22. . After the edge signal detection of all the image signals on the document is completed, the image signal data of the page memory 20 and the edge signal data of the edge signal storage memory 22 are input to the edge signal remover 50 one by one (step S4).
2). The edge signal remover 50 takes the difference between the input image signal and the edge signal (step S43), and outputs the difference in order (step S44). That is, if a certain image signal is not an edge signal, the image signal is output as it is, and if it is an edge signal, the edge signal is removed and information indicating that there is no image signal at that position is output. . The signal output from the edge signal remover 50 is input to the signal processing circuit 3. The subsequent operation is the same as that of the first embodiment, and thus the description thereof is omitted.

Since the image signal does not originally exist at the edge of the document, there is no problem even if the edge signal is simply removed. As described above, by outputting the difference between the edge signal and the image signal, only the original image signal without the edge signal can be obtained. As a result, it is possible to obtain a high quality copied image 5 of only the original image.

Embodiment 7 FIG. 9 is a block diagram showing the flow of image signals in a copying machine according to an embodiment of the present invention. In FIG. 9, the parts denoted by the same numbers as in FIG. 6 indicate the same or corresponding parts, and thus the description thereof will be omitted. In the fifth and sixth embodiments, the page memory 20 is used to remove the edge signal. However, in the seventh embodiment, the edge of the original written on the paper or the like is used without using the memory such as the page memory. Is detected as an edge signal from the image signal, and the detected edge signal is removed from the image signal. FIG. 10 shows Example 7.
3 is a flowchart showing an operation procedure of edge signal removal in FIG.

The image signal read from the original image 1 by the image signal reading device 2 and converted into a digital electric signal is input to the edge signal detector 21. Similar to the third or fourth embodiment, the edge signal detector 21 performs edge signal detection processing (step S51), and when the detection processing ends, the image signals are sequentially input to the edge signal remover 50 (step S52). ). When the edge signal detector 21 detects an edge signal from the image signal, the edge signal detector
An edge signal detection signal is sent from 21 to the edge signal remover 50. It is determined whether or not an edge signal detection signal is sent (step S53), and when the edge signal remover 50 receives the edge signal detection signal, the corresponding image signal is determined to be an edge signal and removed (step S54). This means that the image signal does not exist at the position where the edge signal existed, but since the image signal originally does not exist at the edge of the document, there is no problem even if the edge signal is simply removed.

As described above, by removing the edge signal from the image signal, only the original image signal having no edge signal can be obtained. As a result, it is possible to obtain a high quality copied image 5 of only the original image.

Although the image signal processing circuit of the copying machine has been described in each of the above-described embodiments, the image signal processing circuit of the image signal reading device such as a scanner can also be used.
Similarly, it is possible to provide an edge signal detector and an edge signal remover.

Further, the edge signal detector and the edge signal remover in each of the above-mentioned embodiments can be produced by using an ASIC such as a gate array for processing a digital signal. It is also possible to obtain an edge signal detector and an edge signal remover by making it possible to process the image signal data by the CPU of the copying machine constituted by the microcomputer IC.

[0061]

As described above, according to the first aspect of the present invention, the signal of the shadow of the edge of the document which is not the original image signal is detected from the image signals read from the document image, and the shadow of the edge of the detected document is detected. Since this signal is removed from the image signal, it is possible to obtain an image signal from only the original document image.

According to the second aspect of the invention, even in the case where another original is pasted on the original, the edge of the pasted original which is not the original image signal is detected from the image signals read from the original image. Since the edge shadow signal is removed from the image signal by detecting the shadow signal and substituting the image signal around the detected edge shadow signal of the original, only the original image of the original is read as in the case of a normal original. The image signal from can be obtained.

According to the third aspect of the invention, the shadow signal of the edge of the original which is not the original image signal is detected from the image signals read from the original image, and the detected shadow signal of the edge of the original is input to the input image signal. Since the edge shadow signal is removed from the image signal by subtracting from, the image signal can be obtained from only the original document image.

According to the fourth aspect of the invention, the detecting means for detecting the shadow signal of the edge of the original which is not the original image from the image signals read from the original image, and the signal of the shadow of the detected edge of the original are image signals. The image signal can be obtained only from the original image of the original document, since it is provided with a removing unit for removing the original image.

According to the fifth aspect of the invention, in the fourth aspect of the invention, since the detection signal notifying that the edge shadow signal of the document has been detected is output from the detection means to the removal means, the removal means outputs the edge shadow signal. It can be reliably removed from the image signal.

According to the sixth aspect of the present invention, the storage means for storing the image signal read from the original image, the image signal from the storage means are read out, and the signal of the shadow of the edge of the original which is not originally the image is read based on the density value. Since the detecting means for detecting the edge shadow and the removing means for removing the detected edge shadow signal from the image signal are provided, the edge shadow signal of the original can be easily removed from the image signal, and the original original image It is possible to obtain the image signal from only

According to the seventh aspect of the invention, the storage means for storing the image signal read from the original image, the image signal from the storage means, and the signal of the shadow of the edge of the original which is not originally an image are read based on the density value. Since the detection means for detecting the edge shadow, the storage means for storing the detected edge shadow signal, and the removing means for removing the detected edge shadow signal from the image signal, Can be read out freely, the signal of the shadow of the document edge can be easily removed from the image signal, and the image signal can be obtained only from the original document image.

According to the eighth aspect of the invention, even in the case where another original is pasted on the original, the shadow signal of the edge of the pasted original is detected or the detected shadow signal of the edge is detected. Since it can be removed from the image signal, the same effects as the fourth to seventh inventions can be obtained.

According to the ninth aspect of the invention, there are provided detecting means for detecting the signal of the shadow of the edge of the document based on the density value in the predetermined area, and removing means for removing the signal of the shadow of the edge of the detected document from the image signal. Since it is provided, when a document of a predetermined size is used, the shadow signal of the edge of the document can be easily detected, and an image signal from only the original document image can be obtained.

According to the tenth aspect of the invention, the detecting means for detecting the shadow signal of the edge of the document which is not the image signal originally and is erroneously input as the image, and the detected shadow signal of the edge are removed from the image signal. Since the copying machine is provided with the removing means, it is possible to obtain an image signal only from the original image of the original, and as a result, the shadow of the edge of the original does not appear in the copied image, but only the original image. It is possible to obtain a high quality copied image.

As described above, according to the present invention, when a document image is copied, the shadow of the edge of the document that is not the original image is prevented from appearing in the copied image, and only the document image is printed faithfully. It has an excellent effect that it is possible to obtain a high-quality copied image.

[Brief description of drawings]

FIG. 1 is a block diagram showing the flow of image signals in a copying machine according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of edge signal detection according to an embodiment of the present invention.

FIG. 3 is a flowchart showing an operation procedure of edge signal detection according to an embodiment of the present invention.

FIG. 4 is a block diagram showing the flow of image signals in a copying machine according to another embodiment of the present invention.

FIG. 5 is a flowchart showing an operation procedure of edge signal detection according to another embodiment of the present invention.

FIG. 6 is a block diagram showing a flow of image signals in a copying machine according to still another embodiment of the present invention.

FIG. 7 is a flowchart showing an operation procedure of edge signal removal according to an embodiment of the present invention.

FIG. 8 is a flowchart showing an operation procedure of edge signal removal according to another embodiment of the present invention.

FIG. 9 is a block diagram showing a flow of image signals in a copying machine according to still another embodiment of the present invention.

FIG. 10 is a flowchart showing an operation procedure of edge signal removal according to still another embodiment of the present invention.

FIG. 11 is a block diagram showing the flow of image signals in a conventional copying machine.

[Explanation of symbols]

 1 original image 2 image signal reading device 3 image signal processing circuit 4 image signal printing device 5 copied image 20 page memory 21 edge signal detector 22 edge signal storage memory 50 edge signal remover

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area H04N 1/38

Claims (10)

[Claims] 1. A method of detecting and removing a shadow signal of an edge of a document from an image signal obtained from a document, detecting a shadow signal of an edge of the document from the image signal based on a density value, and detecting the detected edge. A method for removing an edge shadow signal of a document, characterized in that the shadow signal of the image is removed from the image signal. 2. A method of detecting and removing a signal of a shadow of an edge of the second original portion from an image signal obtained from an original formed by pasting a second original portion on the first original portion,
The signal of the shadow of the edge of the document is detected from the image signal based on the density value, and when the signal of the shadow of the edge is detected, the signal of the shadow of the edge is used by using the peripheral image signal which is not the signal of the shadow of the edge. A method for removing an edge shadow signal of a document, which is characterized in that 3. A method of detecting and removing a shadow signal of an edge of a document from an image signal obtained from a document, detecting a shadow signal of an edge of the document from the image signal based on a density value, and inputting the image. A method of removing an edge shadow signal of a document, which comprises removing a signal of an edge shadow by obtaining a difference between the signal and a signal of the edge shadow. 4. A detecting means for detecting an image signal having a density equal to or lower than a predetermined density as an image shadow signal of an edge of an original from an image signal obtained from the original document, and a removing means for removing the detected edge shadow signal from the image signal. An image signal processing device comprising: 5. The image signal processing according to claim 4, wherein the detecting means is configured to output the detection signal to the removing means when detecting the shadow signal of the edge of the document. apparatus. 6. Storage means for storing an image signal obtained from a document, detection means for detecting a signal of a shadow of an edge of the document based on a density value from the image signal stored in the storage means, and detection means. An image signal processing device, comprising: a removing unit that removes the signal of the shadow of the edge from the image signal. 7. Storage means for storing an image signal obtained from a document, detection means for detecting a shadow signal of an edge of the document based on a density value from the image signal stored in the storage means, and detection means. An image signal processing apparatus comprising: a storage unit that stores a signal of a shadow of the edge, and a removal unit that removes a signal of the shadow of the detected edge from the image signal. 8. The manuscript has a second manuscript part attached on a first manuscript part, and the detection means is the second manuscript part.
The image signal processing apparatus according to claim 4, wherein the image signal processing apparatus is configured to detect a shadow signal of an edge of a document portion. 9. A detecting means for detecting an image signal having a density equal to or lower than a predetermined density existing in a predetermined area of an original from among image signals obtained from the original as a shadow signal of an edge of the original, and a detected shadow signal of the edge. And a removing means for removing from the image signal. 10. A reading unit for reading an image of a document to obtain an image signal, a detecting unit for detecting a signal of a shadow of an edge of the document from the obtained image signal, and a signal of a shadow of the detected edge from the image signal. Copying comprising removal means for removing, signal processing means for performing signal processing for printing an image signal from which edge shadow signals have been removed, and printing means for printing the processed image signal Machine.