JP3910120B2 - Image processing apparatus, method, program for executing the method, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus, an image processing method, a program for executing the method, and a recording medium, and more particularly, for reducing and storing a multi-value gray image or a color image and enlarging and using the reduced image. The present invention relates to image processing technology.
[0002]
[Prior art]
FIG. 5 is a diagram for explaining a processing example of a conventional image processing system, in which a multi-value gray image or color image of a document is input and stored by a scanner, and is used for distribution, screen display, print output, OCR, and the like. 1 shows an image processing system to be reused. In the image processing system, the digital image signal 32b read from the scanner 31 is input to the PC 32 through the scanner interface (I / F) 32a and stored in the hard disk 33 through the hard disk I / F 32c. When the digital image stored in the hard disk 33 is reused, the digital image taken out through the hard disk I / F 32c is printed on the printer through the printer I / F 32d, or the digital image is subjected to compression processing 32e or uncompressed processing. The information is distributed to the outside through the communication I / F 32h by 32f, or the binary image for OCR binarized by the binarization processing 32g is output to the outside through the communication I / F 32h.
[0003]
[Problems to be solved by the invention]
In the conventional example as described above, a digital image having basically the same resolution as that read by the scanner 31 is stored in the hard disk 33. In this way, when storing multi-value gray images or color images input using a color scanner or digital camera and reusing them for purposes such as distribution, screen display, printout, OCR, etc. Consider the trade-off between storage capacity and processing time.
[0004]
In other words, it is effective to input an image at a high resolution in order to obtain more information about a document or subject. However, the size of an image file input at a high resolution consumes a large amount of storage device capacity and processing time. Also gets longer. Lower resolution input saves space and time, but at the cost of missing information.
[0005]
Accordingly, the present invention provides an image processing apparatus capable of ensuring both a certain level of maintaining a high image quality by securing the amount of image information of a document and reducing the storage capacity and processing time of image data. It is an object to provide a method and a recording medium on which a program for executing the method is recorded.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an image input means for inputting a multi-value gray image or a color image as an original image, and an image reduction means for reducing an image (original image) obtained from the image input means by resolution conversion. Image extraction means for extracting a part of (original image) obtained by the image input means, reduced image storage means for saving an image (reduced image) obtained by the image reduction means, and resolution conversion information in the image reduction means Resolution conversion information storage means for saving, partial original image storage means for saving an image (partial original image) obtained from the image extraction means, and position information in the original image of each pixel of the partial original image obtained from the image extraction means a partial original image position information storage means for storing (partial original image position information), the reduced image obtained by the image reduction unit, the pixel of interest and its surrounding picture A feature amount calculation means for calculating a feature amount from the pixel value of the pixel value, and the image extraction means uses the feature amount calculated by the feature amount calculation means to change the degree of change with respect to surrounding pixels to a certain level or more. A pixel in a related original image is extracted, and the extracted pixel is used as the partial original image . With this feature, it is possible to achieve both a certain level of maintaining the information amount of the document as much as possible and saving the storage capacity as much as possible.
[0007]
Further, by enlarging the reduced image using the reduced image and the resolution conversion information, an image enlarging unit that generates an image having the same resolution as the original image, an image (enlarged image) obtained from the image enlarging unit, and a part The image processing apparatus is characterized by comprising combining means for combining the partial original image with an image having the same resolution as the original image, using the position information of the original image and the partial original image. With this feature, it is possible to achieve both a certain level of maintaining the document information amount and saving the processing time as much as possible.
[0008]
The image processing method of the present invention includes an image input step for inputting a multi-value gray image or a color image, an image reduction step for reducing an image (original image) obtained by the image input step by resolution conversion, and an image input step. Image extracting step for extracting a part of an image (original image) to be obtained, a reduced image storing step for storing an image (reduced image) obtained from the image reducing step, and resolution conversion information for storing resolution conversion information in the image reducing step A storage step, a partial image storage step for storing the image (partial original image) extracted from the image extraction step, and position information (partial original image position) of each pixel of the partial original image extracted from the image extraction step a reduced image obtained by the partial original image position information storage step and the image reduction means for storing information) A feature amount calculation step of calculating a feature amount from a pixel value of the target pixel and its surrounding pixels, and the image extraction step uses the feature amount calculated in the feature amount calculation step to change the surrounding pixels. A pixel in an original image related to a pixel having a certain degree of or more is extracted, and the extracted pixel is used as the partial original image.
[0009]
In addition, the image processing method of the present invention enlarges the reduced image using the reduced image and the resolution conversion information, thereby generating an image having the same resolution as the original image, and an image obtained from the image enlargement step. (Enlarged image), the partial original image, and the partial original image position information are used to combine the partial original image with an image having the same resolution as the original image.
[0010]
The present invention includes an image input step of inputting a multi-value gray image or a color image;
An image reduction step for reducing the image (original image) obtained from the image input step by resolution conversion, an image extraction step for extracting a part of the image (original image) obtained from the image input step, and an image reduction step. Reduced image storage step for storing an image (reduced image), resolution conversion information storage step for storing resolution conversion information during the image reduction step, and partial image storage for storing an image (partial original image) obtained from the image extraction step A partial original image position information storage step for storing position information (partial original image position information) in the original image of each pixel of the partial original image obtained from the image extraction step, and a reduction obtained by the image reduction means A feature amount calculating step for calculating a feature amount from a pixel value of a target pixel and surrounding pixels of the image; The image extraction step uses the feature amount calculated in the feature amount calculation step to extract a pixel in the original image related to a pixel whose degree of change with respect to surrounding pixels is a certain level or more, and extracts the extracted pixel as the partial original. The present invention is implemented by a program for executing an image processing method as an image and a computer-readable recording medium that records the program.
[0011]
Further, the present invention enlarges the reduced image using the reduced image and the resolution conversion information, thereby generating an image having the same resolution as the original image, and an image (enlarged image) obtained from the image enlargement step. ), A program for executing an image processing method including a partial original image and a composition step of combining the partial original image with an image having the same resolution as the original image using the position information of the partial original image, and the program Implemented by the recorded recording medium.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram for explaining the configuration of the image processing apparatus of the present invention. The image processing apparatus includes an image input unit 1 that inputs a multi-value gray image or a color image as an original image, an image reduction unit 2 that reduces the original image obtained from the image input unit 1 by resolution conversion, and a part of the original image. Is extracted as a partial original image, a reduced image storage unit 4 that stores a reduced image obtained by the image reduction unit 2, and a resolution conversion information storage unit 5 that stores resolution conversion information in the image reduction unit 2. A partial image storage unit 6 for storing the partial original image extracted by the image extraction unit 3, and a partial original image position for storing position information in the original image of each pixel of the partial original image extracted by the image extraction unit 3 An information storage means 7 is provided.
[0013]
The image processing apparatus enlarges the reduced image using the reduced image and the resolution conversion information, thereby generating an image enlargement unit 8 that generates an image having the same resolution as the original image, and the enlargement obtained by the image enlargement unit 8. Using the image, the partial original image, and the position information of the partial original image, a combining unit 9 is provided for combining the partial original image with an image having the same resolution as the original image. Furthermore, it has a feature quantity calculation means 10 for calculating the feature quantity of each pixel of the reduced image, and the feature quantity obtained by the feature calculation means 10 is used for the extraction of the partial original image by the image extraction means 3.
[0014]
FIG. 2 is a block diagram for explaining processing in an embodiment of the present invention. 11 is a scanner for inputting a multi-value gray image or color image from a document, 12 is a PC (personal computer), 13 is image data and control. A hard disk for storing information, and a printer 14 for outputting image data to paper.
[0015]
The digital image signal 12b from the scanner 11 enters the PC 12 through the scanner I / F 12a, and the PC 12 performs reduction and extraction processing 12i on the digital image, and the resolution-reduced image, the original original partial original image, and control information ( Resolution conversion rate, partial original image position information, etc.). These reduced-resolution images, partial original images, and control information are stored in the hard disk 13 through the hard disk I / F 12c.
[0016]
When reusing image data stored on the hard disk, the resolution-reduced image, the original resolution partial image, and control information are read from the hard disk 13, and a data image having the same resolution as the original image is generated by enlarging and synthesizing 12j. To do. The image data is passed to the printer 14 via the printer I / F 12d and output to paper, or the PC 12 performs compression processing 12e such as JPEG, non-compression processing 12f, binarization processing 12g, etc. The data is output to the outside through F12h as data for data distribution, on-screen display, OCR, and the like.
[0017]
FIG. 3 is a flowchart for explaining a processing example in the image processing method of the present invention. First, high resolution (for example, 600 dpi) original image data 21 is input from the scanner (step S1). Next, resolution reduction processing is performed on the high-resolution original image data 21 input from the scanner (step S2). Here, for example, the resolution is reduced and converted from 600 dpi to 100 dpi. For example, a simple average reduction method is adopted as the conversion method. The image size after reduction is 1/36 of the original. The average value of 6 × 6 = 36 pixels in the original image becomes the pixel value of one pixel after reduction.
[0018]
Next, with respect to the reduced image 22 obtained by the above-described image reduction processing, a feature amount representing the degree of image change at the target pixel is calculated (step S3). For example, an edge map is calculated by Sobel's edge detection method (Randy Crane, A Improved Applied to Image Processing, Prentice-Hall, 1997).
[0019]
Next, control information related to the partial pixels of the original image is extracted using the feature amount 23 of the reduced image and the original image data 21 calculated in the feature calculation process (step S4). In this extraction process, for example, for a pixel having an edge intensity of a certain level or more in the edge map, a plurality of pixels in the original image related to the pixel are extracted, and the extracted partial original image data and control information ( The resolution conversion rate information between the original image and the reduced image, and the position information of the extracted pixels in the original image) 24 are extracted.
[0020]
Then, enlargement and composition processing is performed using the reduced image 22, the partial original image data and the control information 24 (step S5). The enlargement / combination process combines the enlarged image 25 having the same high resolution as the original image, and uses, for example, a linear interpolation method. In the synthesis process, referring to the control information, if there is an original image that is partially stored, the pixel of the original image is replaced with the pixel of the enlarged image at the corresponding location of the enlarged image.
[0021]
4A and 4B are diagrams for explaining an image obtained by image processing according to the present invention. FIG. 4A is a diagram illustrating a high-resolution (600 dpi) original image, and FIG. 4B is a reduced image obtained by reducing the original image. 4D is a diagram showing the edge map of the feature amount of the reduced image (black and white inverted for display), and FIG. 4D is a diagram showing the control information. 4 shows a state in which the edge map of FIG. 4C is binarized with a certain threshold value.
[0022]
The original image (FIG. 4A) input to the image processing apparatus is reduced to an image (FIG. 4B) by image reduction processing, feature amounts are extracted by feature calculation, and an edge map (FIG. 4C) is obtained. ) Is generated. And control information (Drawing 4D) is extracted by extraction processing. Here, the control information in FIG. 4D is information for pixels having edge intensity equal to or higher than a certain intensity, and setting the pixels to black and the others to white.
[0023]
Then, an image (partial original image) of a portion corresponding to black in FIG. 4D is extracted from the original image (FIG. 4A) (not shown). FIG. 4E is an enlarged view of the reduced image of FIG. 4C to the original resolution. In this enlarged image, a portion corresponding to the extracted partial original image is converted into a partial original image using control information. replace. FIG. 4F is an enlarged view synthesized using the partial original image thus extracted and the control information of FIG. As can be seen from this example, the capacity required to store the reduced image, the partial original image and the control information can be smaller than the capacity of the original image. Further, the enlarged and synthesized image (FIG. 4F) is not as large as the original image, but has a larger amount of information than a simple enlarged image (FIG. 4E), and a high quality image can be obtained.
[0024]
【The invention's effect】
As described above, according to the present invention, it is possible to achieve both a certain level of securing the image information amount of a document and maintaining high image quality, and reducing the storage capacity and processing time of image data. An image processing apparatus, a method, a program for executing the method, and a recording medium can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram for explaining a configuration of an image processing apparatus of the present invention.
FIG. 2 is a block diagram for explaining processing in an embodiment of the present invention.
FIG. 3 is a flowchart for explaining a processing example in the image processing method of the present invention.
FIG. 4 is a diagram illustrating an image obtained by image processing according to the present invention.
FIG. 5 is a diagram for explaining a processing example of a conventional image processing system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image input means, 2 ... Image reduction means, 3 ... Image extraction means, 4 ... Reduced image storage means, 5 ... Resolution conversion information storage means, 6 ... Partial original image storage means, 7 ... Partial original image position information storage means , 8 ... Image enlargement means, 9 ... Composition means, 10 ... Feature quantity calculation means, 11 ... Scanner, 12 ... PC (personal computer), 13 ... Hard disk, 14 ... Printer, 21 ... Original image data, 22 ... Reduced image, 23 ... feature amount, 24 ... partial original image and control information, 25 ... enlarged image, 31 ... scanner, 32 ... PC, 33 ... hard disk.

Claims (6)

Image input means for inputting a multi-value gray image or color image as an original image;
Image reduction means for reducing the original image obtained from the image input means by resolution conversion;
Image extracting means for extracting a part of the original image as a partial original image;
Reduced image storage means for storing a reduced image obtained by the image reduction means;
Resolution conversion information storage means for storing resolution conversion information in the image reduction means;
Partial original image storage means for storing the partial original image extracted by the image extraction means;
Partial original image position information storage means for storing position information in the original image of each pixel of the partial original image extracted by the image extraction means;
About the reduced image obtained by the image reduction means, the feature amount calculation means for calculating the feature amount from the pixel value of the target pixel and its surrounding pixels,
The image extraction unit extracts a pixel in an original image related to a pixel whose degree of change with respect to surrounding pixels is a certain level or more using the feature amount calculated by the feature amount calculation unit, and extracts the extracted pixel as the part An image processing apparatus characterized by being an original image . Image enlarging means for enlarging the reduced image using the reduced image and the resolution conversion information to generate an image having the same resolution as the original image;
Using a magnified image obtained by the image enlarging means, the partial original image, and position information of the partial original image, and combining means for synthesizing the partial original image with an image having the same resolution as the original image. The image processing apparatus according to claim 1. An image input step for inputting a multi-value gray image or a color image;
An image reduction step of reducing the original image obtained from the image input step by resolution conversion;
An image extraction step of extracting a part of the original image;
A reduced image storage step for storing a reduced image obtained by the image reduction step;
Resolution conversion information storage step for storing resolution conversion information in the image reduction step;
A partial original image storage step for storing the partial original image extracted by the image extraction step;
A partial original image position information storage step for storing position information in the original image of each pixel of the partial original image extracted by the image extraction step;
A feature amount calculating step of calculating a feature amount from a pixel value of a target pixel and its surrounding pixels with respect to the reduced image obtained by the image reduction means;
The image extraction step uses the feature amount calculated in the feature amount calculation step to extract pixels in the original image related to pixels whose degree of change with respect to surrounding pixels is equal to or greater than a certain level, and extracts the extracted pixels as the portion An image processing method characterized in that it is an original image . An image enlargement step of generating an image having the same resolution as the original image by enlarging the reduced image using the reduced image and resolution conversion information;
Using the enlarged image obtained in the image enlargement step, the partial original image, and the position information of the partial original image, and synthesizing the partial original image with an image having the same resolution as the original image. The image processing method according to claim 3 . A program for executing the image processing method according to claim 3 . A recording medium on which the program according to claim 5 is recorded.

Images