JPH0453346A - Marker eliminating device - Google Patents

Abstract

PURPOSE:To obtain a binarized picture signal with high quality by applying processing of eliminating a picture input signal on a marker when its level is lower than an upper limit of a gray level of the marker and applying processing of not eliminating the picture input signal when the level is higher than the upper limit. CONSTITUTION:A marker elimination device consists of an area recognition circuit 1, a comparator 2, a NAND gate 3 and an AND gate 4, and the comparator 5 forms a binarizing circuit converting a multivalue output into a binary output. Then a picture input signal is eliminated when the picture input signal is on a marker and the level of the picture input signal is lower than the upper limit of a gray level of the marker and the picture input signal is not eliminated when the picture input signal is higher than the upper limit. As a result, a white level picture output signal is obtained where the marker is not formed, e.g. on character information, and character information is obtained where the marker and the character information are overlapped. Thus, a binarized picture signal with high quality is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a marker removing device, and more particularly to a marker removing device that removes markers written on a document.

(Prior art) Conventionally, image processing for copying machines, facsimile machines, etc. allows you to specify any area on a document, detect that area, and easily perform predetermined image editing in real time without cutting and pasting the document. equipment is required.

Currently, as an image processing apparatus that meets these demands, an image processing apparatus that allows desired image editing to be performed by specifying an arbitrary area on a document with a marker pen of a predetermined density has been put into practical use. This image processing device is compatible with a binary output printer, and recognizes a marker specified by the marker pen as gray within a predetermined density area.

When the image processing device starts operating, it detects a marker on the document, detects whether the document information is outside the marker, on the marker, or within a closed area by the marker, and performs image editing based on the result. Output as a value image signal.

This type of image processing device removes the marker by setting the threshold level when binarizing the image signal between the upper limit of the gray level of the marker and the black level. is prevented from appearing in the binary image output signal. Also, when this process is performed, only the marker is removed from the document information part where the marker has been overpainted, and the background image of the document is output as is.
A high quality binary image signal output can be obtained.

(Problem to be Solved by the Invention) However, in the conventional marker removal device, the threshold value when binarizing the image signal must be set between the upper limit of the gray level of the marker and the black level. Naturally, even if an optimal level exists below the upper limit value of the gray level, there is a problem in that it is not possible to set that value.

Furthermore, the conventional marker removing device is compatible with printers that output binary values, and there is a problem in that it cannot be used with printers capable of multi-value output that have been put into practical use in recent years.

An object of the present invention is to eliminate the problems of the conventional device, and to set the threshold value to an arbitrary value when binarizing an image signal.
Another object of the present invention is to provide a marker removing device that can also be used in a printer capable of multivalued output.

(Means and Effects for Solving the Problem) In order to achieve the above object, the present invention provides an area recognition circuit that detects that it is on a marker, and a region recognition circuit that compares an image input signal with an upper limit value of the gray level of the marker. From the outputs of the area recognition circuit and the comparator, when the image input signal is on the marker and the image input signal is less than the upper limit value, the image input signal is removed; The image input signal is characterized in that it is provided with means for not removing the image input signal when the image input signal is large.

According to the present invention, the area recognition circuit detects that the area is on the marker, and the comparator detects the magnitude between the image input signal and the upper limit value of the gray level of the marker. Then, when the image input signal is on the marker and is less than the upper limit of the gray level of the marker, the image input signal is removed, and when it is on the marker, the image input signal is not removed.

As a result, for example, a white image output signal is obtained where the marker is not placed on the text information, and text information is obtained where the marker and the text information overlap.

Moreover, in the invention of claim (2), an image output signal of the background color is obtained at a place where the character information and the marker do not overlap.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a circuit diagram of an embodiment of the present invention. Also, the second
The figure is a diagram showing an example of information written on a manuscript and its density.

In FIG. 2, if the density on the dotted line 10 in the main scanning direction on the original information "A The density becomes gray. Level b in the figure is the upper limit of the gray level of the marker.

In FIG. 1, 1 is an area recognition circuit, 2 is a comparator, 3 is a NAND gate, and 4 is an AND gate, which constitute a marker removal device. Further, 5 is a comparator, which constitutes a binarization circuit that converts a multi-value output into a binary output.

The area recognition circuit 1 detects the marker 11 from the image input signal a.
The circuit detects, for example, a first comparator having a threshold value larger than the upper limit value of the gray level, a second comparator having a threshold value smaller than the upper limit value, and a first comparator having a threshold value smaller than the upper limit value. ．．
and a gate that performs AND processing on the outputs of the two comparators.

When this area recognition circuit 1 detects a marker from the image input signal a, it outputs an H (high) level signal while detecting the marker, and when the marker detection is finished, it outputs an L (low) level signal.
Outputs a level signal.

Therefore, the area recognition circuit 1 outputs the marker-on signal C of H level only above the marker.

The comparator 2 compares the image input signal a input to the A terminal with the upper limit value of the gray level of the marker input to the B terminal, and outputs an H level signal when b≧a. Further, the comparator 5 outputs an H level signal when the A terminal human power f is larger than the B terminal human power g (A>B).

Next, the operation of the circuit shown in FIG. 1 will be explained with reference to the waveform diagram shown in FIG.

Now, suppose that a multivalued (6-bit) image input signal a as shown in FIG. 3 is input to the area recognition circuit 1, and the area recognition circuit 1 outputs a marker top signal C. . This marker signal C enters one input terminal of the NAND gate 3.

Further, since the image input signal a is inputted to the A terminal of the comparator 2, and the upper limit value of the gray level of the marker is applied to the B terminal, the image input signal a is inputted from the comparator 2.
It outputs a signal d which becomes H level when is smaller than the upper limit value.

When the signals C and d are input to the NAND gate 3,
The NAND gate 3 outputs an L level signal e only on the marker. This signal is input to one terminal of AND gate 4.

On the other hand, since the image input signal a is input to the other terminal of the AND gate 4, the AND gate 4 outputs the image signal f from which the marker has been removed.

This image signal f is input to one terminal A of the comparator 5.

Since a threshold value g for binarizing the image signal is applied to the other terminal B of the comparator 5, the comparator 5 obtains an image signal obtained by binarizing the multi-level signal. It will be done.

As described above, according to this embodiment, the marker can be removed from the image input signal a. Further, the threshold value g for binarization can be freely set without being limited to a value between the upper limit of the gray level of the marker and the black level as in conventional devices. Therefore, it is possible to use the optimal threshold value g according to the image input signal a, and to obtain high-quality
A valued image signal can be obtained.

Furthermore, an L level image output signal is obtained where the marker is placed on a white background, and an H level signal is obtained where the marker overlaps the document information.

Next, a second embodiment of the present invention will be described with reference to FIG.

This embodiment differs only in that the AND gate 4 of the first embodiment is replaced with a multiplexer 7 to which a background level signal i is applied to the A terminal, and the other configurations are the same. Note that the same reference numerals in FIG. 4 as in FIG. 1 indicate the same or equivalent parts.

The multiplexer 7 selects the A terminal when an L level signal is input, and selects the B terminal when an H level signal is input.

Therefore, according to this embodiment, after the marker is removed from the image input signal a, the signal i at a predetermined background level is replaced.

Therefore, even if the background color is light gray or the like, after removing the marker, the background color such as light gray can be replaced instead of white, and a natural image output signal that does not give an unnatural feeling can be obtained.

(Effects of the Invention) As described above, according to the present invention, markers can be removed from multivalued image input signals.

In addition, the threshold value for binarizing the multivalued image signal from which the marker has been removed is not limited to the value between the upper limit of the gray level of the marker and the black level as in conventional devices, but can be set freely. Since the settings can be made, a high quality binary image output signal can be obtained.

Furthermore, by connecting the marker removal device of the present invention to a multi-value printer, it is possible to print out a multi-value image from which markers have been removed.

Furthermore, by replacing the background density after the removed marker, a natural image output signal can be obtained even for document information with background texture.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the concentration level of a marker, FIG. 3 is a waveform diagram of the main part of the signal in FIG. FIG. 2 is a circuit diagram of a second embodiment. 1... Area recognition fence, 2, 5... Comparator, 3...
NAND gate, 4...AND gate, 7...Multiplexer agent Patent attorney Michito Hiraki and 1 other person

Claims (2)

[Claims] (1) A marker removal device configured to remove a marker from a multivalued image input signal, comprising: an area recognition circuit that detects that the marker is on the marker; and an upper limit value of the gray level of the image input signal and the marker. a comparator for comparing the outputs of the area recognition circuit and the comparator; and removing the image input signal when the image input signal is on the marker and is below the upper limit; 1. A marker removal device comprising means for not removing the image input signal for poems larger than the value. (2) A marker removal device configured to remove a marker from a multivalued image input signal, comprising: an area recognition circuit that detects that the marker is on the marker; and an upper limit value of the gray level of the image input signal and the marker. a comparator for comparing the area recognition circuit and the comparator, and outputs a background signal in place of the image input signal when the image input signal is on the marker and is less than the upper limit value from the output of the area recognition circuit and the comparator; A marker removal device characterized by comprising means for not removing the image input signal when the image input signal is larger than the upper limit value.