JPH08340446A - Device and method for image processing - Google Patents

Abstract

PURPOSE: To perform image processing without impairing the gradations of a multi-valued image by the image processor which performs binary image processing when the multi-valued image is inputted. CONSTITUTION: When the multi-valued image is inputted from a multi-valued image input part 1 such as a scanner, a multi-valued resolution conversion part 2 performs resolution conversion where the gradations of the multi-valued image are reflected and then a thresholding part 3 performs thresholding. The binary image is inputted to an area division part 7 through a selector 6 and the area division part 7 divides the binary image into respective areas according to image features and outputs area information to an external device 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and a method thereof, and more particularly, to an image processing apparatus and a method thereof for performing binary image processing.

[0002]

2. Description of the Related Art In a conventional image processing apparatus for performing image processing on a binary image, for example, the resolution of an image to be processed is lowered to shorten the image processing time, or the accuracy of the image processing is improved. Therefore, the resolution of the image to be processed has been increased. Therefore, for example, a binary resolution conversion means using a projection method or the like is provided, and the resolution of the input image is converted as necessary before the target image processing is performed.

Therefore, for example, when the input image is a multi-valued image, the input image is first binarized to make the gradation of the image uniform, and then the resolution conversion means performs the binary resolution conversion as described above. After that, the intended binary image processing was performed.

[0004]

However, in the above-mentioned conventional example, when the input image is a multi-valued image, the multi-valued image is first binarized, and then the binary value is obtained by using a projection method or the like. Since the resolution of the image is converted, the multivalued gradation information was not properly reflected in the binary image after the resolution conversion. That is, multi-value gradation information is not used,
It was abandoned. As a result, the image obtained as a result of the binary image processing is distorted and the image quality of the output image is impaired.

The present invention has been made to solve the above-mentioned problems, and in an image processing apparatus for performing binary image processing, when a multi-valued image is input, the gradation in the multi-valued image is input. An object of the present invention is to provide an image processing apparatus capable of image processing without damaging information and a method thereof.

[0006]

As one means for achieving the above object, the image processing apparatus of the present invention has the following configuration.

That is, a multi-valued image input means for inputting a multi-valued image, a multi-valued resolution conversion means for converting the resolution of the multi-valued image, and a multi-valued image resolution-converted by the multi-valued resolution conversion means It is characterized in that it has a binarizing means for binarizing and an image processing means for performing image processing on the image binarized by the binarizing means.

Further, it has a binary image input means for inputting a binary image and a binary resolution converting means for converting the resolution of the binary image, and the image processing means converts the resolution by the binary resolution converting means. Image processing is performed on the generated binary image.

Further, the image processing means has a selection means for selecting either the image binarized by the binarization means or the binary image resolution-converted by the binary resolution conversion means. Image processing is performed on the binary image selected by the selecting means.

For example, the selecting means selects the image binarized by the binarizing means when the multivalued image is inputted by the multivalued image inputting means, and the binary image is inputted by the binary image inputting means. When the value image is input, the binary image whose resolution is converted by the binary resolution conversion means is selected.

For example, the multi-valued image input means is characterized by reading an image signal by optically scanning a document image.

For example, the multivalued resolution conversion means is characterized in that the resolution is converted by changing the scanning speed in the multivalued image input means.

For example, the image processing means is characterized in that the binary image is divided into a plurality of areas based on the image characteristics.

For example, the image processing means is characterized by performing a character recognition process on a region divided as a character region in the binary image.

For example, the image processing means is characterized by applying image compression to each area divided in the binary image.

As one method for achieving the above object, the image processing method of the present invention comprises the following steps.

That is, a multi-valued image input step of inputting a multi-valued image, a multi-valued resolution conversion step of converting the resolution of the multi-valued image, and a multi-valued image whose resolution is converted in the multi-valued resolution conversion step are divided into two. It is characterized by including a binarizing step of binarizing and an image processing step of performing image processing on the image binarized in the binarizing step.

Further, it has a binary input step of inputting a binary image and a binary resolution conversion step of converting the resolution of the binary image. In the image processing step, resolution conversion is performed in the binary resolution conversion step. Image processing is performed on the generated binary image.

Further, there is a selection step of selecting either the image binarized in the binarization step or the binary image resolution-converted in the binary resolution conversion step,
In the image processing step, image processing is performed on the binary image selected in the selection step.

For example, in the selection step, when a multi-valued image is input in the multi-valued image input step, the image binarized in the binarization step is selected, and in the binary image input step, When a value image is input, the resolution-converted binary image is selected in the binary resolution conversion step.

[0021]

With the above configuration, when a multi-valued image is input, first, multi-valued resolution conversion is performed, and thereafter, binarization is performed to obtain 2 values.
By generating the value image, it is possible to obtain a unique effect that a good image can be obtained in the output image after the image processing without damaging the gradation information in the multivalued image.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the drawings.

<First Embodiment> FIG. 1 is a block diagram showing the arrangement of an image processing apparatus according to this embodiment. In FIG.
Reference numeral 1 is a multi-valued image input unit that captures a multi-valued image with a scanner or the like, 2 is a multi-valued resolution conversion unit that performs resolution conversion of a multi-valued image, 3 is a binarization unit that binarizes a multi-valued image, and 4 is For example, a binary image input unit 5 of a facsimile receiver or the like is a binary resolution conversion unit that performs resolution conversion of a binary image using a projection method. Reference numeral 6 is a selector for selecting one of the output of the binarization unit 3 and the output of the binary resolution conversion unit 5, and 7 is a binary image depending on its image feature such as a character portion, a title portion, a halftone portion, a line portion, or Is an area dividing unit that divides each area such as a front portion, and 8 is an external device connected to the area dividing unit 7, such as a computer, a printer, or a facsimile.

The operation of the image processing apparatus having the configuration shown in FIG. 1 will be described in detail below.

First, the multi-valued image read by the multi-valued image input unit 1 is input to the multi-valued resolution conversion unit 2 and subjected to resolution conversion processing using image processing such as spatial filtering. Therefore, for example, when the resolution is lowered to shorten the processing time, or when the resolution is raised to improve the processing accuracy, the input multi-valued image has an appropriate resolution considering its gradation. The conversion is applied.

Next, the resolution-converted multi-valued image is input to the binarizing unit 3 and converted into a binary image so as to fit in the area dividing unit 7 described later. Then, it is supplied to the area dividing unit 7 via the selector 6.

The area dividing section 7 determines the image feature by performing binary image processing, and divides it into predetermined areas. Here, FIG. 2 shows an example of area division by the area division unit 7. 2A shows an input image, and FIG. 2B shows the result of area division of the input image by the area dividing unit 7. According to FIG. 2B, the input image has a character part (1,
2, 3), title part, halftone part, line part (1,
2), divided into each area such as the front portion.

Then, the area dividing unit 7 extracts area information such as the position and image content of each divided area and outputs the area information to the external device 8 together with the binary image. The external device 8 can perform optimal processing for each area of the binary image according to the input area information.

Here, when the input image is a multi-valued image, the multi-valued resolution conversion unit 2 in the preceding stage performs resolution conversion reflecting multi-valued gradation information, and then the binarization unit 3
Since the binarization processing is performed by the method, an image with less image distortion can be output in consideration of the gradation.

On the other hand, the binary value obtained by the binary image input unit 4
The value image is input to the binary resolution conversion unit 5, converted into an appropriate resolution, and supplied to the area division unit 7 via the selector 6. Then, as described above, the area is divided and output to the external device 8.

The system control unit 9 is a CP for main control.
U, a ROM that stores an operation program of the CPU, fixed variables, and the like, and a RAM that serves as a work area. Depending on whether the input image is a multivalued image or a binary image, for example, a selector It controls the entire image processing apparatus, such as switching of 6 and setting of variables required in each unit.

As described above, according to this embodiment,
When a multi-valued image is input to an image processing apparatus that performs binary image processing, the gradation information in the multi-valued image is effectively used by performing a different process from the case where the binary image is input. Processing can be performed. Therefore, the deterioration of the output image can be prevented.

<Other Embodiments> Another block diagram of the present invention is shown in the block of FIG. In FIG. 3, the same components as those in FIG. 1 described above are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 3, reference numeral 10 denotes an OCR unit, which performs OCR (character recognition) processing only on the area divided as the character portion by the area dividing unit 7. Then, as the character portion, not the image information but the recognized character code information is sent to the external device 8.

With such a configuration, the amount of information output to the external device 8 can be reduced and the character information has already been converted into a character code, so the load on the external device 8 can be reduced. As a result, the throughput can be improved as a whole.

It is also useful to configure the OCR section 10 shown in FIG. 3 as a compression section. By inputting the division result from the area dividing section 7 to the compressing section 10, for example, the compression method is switched between the character section and the halftone section, and the optimum binary value is obtained for each area divided by the area dividing section 7. A compression process can be performed.

In addition, for example, when the multi-valued image input unit 1 is composed of a scanner or the like for optically reading a document image, the optical reading speed of the scanner is made variable to obtain an image signal Good resolution conversion in the sub-scanning direction can be realized. Then, the multi-value resolution conversion unit 2 may perform resolution conversion only in the main scanning direction.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0039]

As described above, according to the present invention, 2
Even when a multi-valued image is input to an image processing apparatus that performs value-based image processing, the gradation information of the multi-valued image is effectively used by binarizing it after performing resolution conversion on the multi-valued image. Since it is possible to perform the image processing that
It is possible to suppress image distortion in the output image and obtain a good output image.

[0040]

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of image area division in the present embodiment.

FIG. 3 is a block diagram showing another configuration example of the present invention.

[Explanation of symbols]

 1 multi-valued image input unit 2 multi-valued resolution conversion unit 3 binarization unit 4 binary image input unit 5 binary resolution conversion unit 6 selector 7 area division unit 8 external device 9 system control unit

Front page continuation (72) Inventor Yuka Nagai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Michiko Hirayu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (13)

[Claims] 1. A multi-valued image input means for inputting a multi-valued image, a multi-valued resolution conversion means for converting the resolution of the multi-valued image, and a multi-valued image resolution-converted by the multi-valued resolution conversion means. An image processing apparatus comprising: a binarizing unit for binarizing; and an image processing unit for performing image processing on an image binarized by the binarizing unit. 2. A binary image input means for inputting a binary image, and a binary resolution conversion means for converting the resolution of the binary image, wherein the image processing means includes the binary resolution conversion means. The image processing apparatus according to claim 1, wherein the binary image whose resolution has been converted is subjected to image processing. 3. The image processing device further comprises a selection unit for selecting one of an image binarized by the binarization unit and a binary image whose resolution is converted by the binary resolution conversion unit. The means is 2 selected by the selecting means.
The image processing apparatus according to claim 2, wherein image processing is performed on the value image. 4. The selecting means selects an image binarized by the binarizing means when a multivalued image is input by the multivalued image inputting means, and the binary image is input by the binary image inputting means. 4. The image processing apparatus according to claim 3, wherein when a value image is input, the binary image whose resolution has been converted by the binary resolution conversion means is selected. 5. The image processing apparatus according to claim 1, wherein the multivalued image input means reads an image signal by optically scanning a document image. 6. The multi-value resolution conversion means changes the scanning speed in the multi-value image input means,
The image processing apparatus according to claim 5, wherein the resolution is converted. 7. The image processing apparatus according to claim 1, wherein the image processing means divides the binary image into a plurality of areas based on the image characteristics. 8. The image processing apparatus according to claim 7, wherein the image processing means performs character recognition processing on an area divided as a character area in the binary image. 9. The image processing apparatus according to claim 7, wherein the image processing means applies image compression to each area divided in the binary image. 10. A multi-valued image input step of inputting a multi-valued image, a multi-valued resolution conversion step of converting the resolution of the multi-valued image, and a multi-valued image whose resolution is converted in the multi-valued resolution conversion step. An image processing method comprising: a binarizing step of binarizing; and an image processing step of performing image processing on the image binarized in the binarizing step. 11. A binary input step of inputting a binary image, and a binary resolution conversion step of converting the resolution of the binary image, wherein the image processing step includes the step of converting the binary resolution. The image processing method according to claim 10, wherein image processing is performed on the binary image whose resolution has been converted. 12. The image processing method further comprises a selection step of selecting either the image binarized in the binarization step or the binary image resolution-converted in the binary resolution conversion step. The image processing method according to claim 11, wherein in the step, image processing is performed on the binary image selected in the selecting step. 13. The selecting step selects an image binarized in the binarizing step when a multivalued image is input in the multivalued image inputting step, and selects 2 in the binarizing image inputting step. 13. The image processing method according to claim 12, wherein when a value image is input, the binary image whose resolution has been converted in the binary resolution conversion step is selected.