JP2003317089A - Method and system for image correction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for image correction with high processing efficiency and superior reproducibility which can generate an image with an inconspicuous seam when images are joined and eliminate the need for operator's skillfulness and manual operation. <P>SOLUTION: A source image as an object of endless processing is inputted (S1). After an overlap quantity is set (S2), an overlap area is generated nearby an end of the source image (S3) and in this overlap area, an optimum border as a minimum error border is determined according to pixel values at the end of the source image and other ends (S4). According to the optimum border, the pixel values are corrected (S5) to output a corrected image after the endless processing (S6). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the creation of images used for printed building materials for decorating interior surfaces of buildings such as walls, floors and ceilings, furniture, fittings, surfaces of featured parts, etc. The present invention relates to a technique for creating a seamless endless image so as not to be conspicuous.

[0002]

2. Description of the Related Art Building material printed matter is much longer (longer) than general printed matter such as publication printed matter and commercial printed matter. For example, considering a printed material to decorate the wall surface, the length from the floor to the ceiling of the building is usually about 2.5 m,
In addition, the horizontal length from the end to the end of the room is about 3.5 m in the case of 6 tatami mats. Therefore, the images for printed materials for building materials are also required to be endless images, that is, a continuous continuous image of at least that length, that is, an endless image.

The long image as described above is printed on the plate cylinder 1 for printing.
It is impossible to fit within the circumference. Therefore, the side of the start end and the side of the end of the image for one circumference in the printing direction are connected (connected) on the plate cylinder to perform plate making. Then, each time the plate cylinder makes one rotation during printing, an image for one circumference is repeatedly printed without interruption, thereby obtaining a long printed matter of an arbitrary length.

However, if the side of the start end and the side of the end in the printing direction of the image for one circumference are simply butted and connected, the image becomes discontinuous at the connecting portion (joint) and the endless image is obtained. Can't get In order to make the plate cylinder image endless, it is necessary to make the discontinuity of both images continuous at the seam of the image and make the seam unrecognizable, that is, seamless. Becomes

Therefore, as a method of making the plate cylinder image endless by seamlessizing the image joints, which is particularly effective in the case of a wood grain pattern, as described in Japanese Patent Publication No. 43-2065, etc. As a wavy line or zigzag broken line, the joint itself is made inconspicuous and the area near the joint is manually added, decolorized, dyed, deleted, etc. by a skilled worker to correct the discontinuity of the image and seamless Has been widely used (prior art).

Further, in recent years, due to the progress of digital image processing technology applying an electronic computer, an original image is read by a scanner to be converted into digital data, and a correction portion is designated by a mouse, a tablet, a cursor or the like on a display device such as a CRT. It has been attempted to further improve workability by a technique such as copying an appropriate image from another portion of the screen or the like and transplanting the image (prior art). Furthermore, the work of making the seams seamless is performed by averaging calculation processing of both side images.
A method of improving efficiency by automatically calculating with a predetermined formula has also been proposed (prior art).

[0007]

However, in the above-mentioned prior art, since the seamless operation is performed manually by a skilled worker, the work efficiency is low and it has become difficult to secure a skilled worker in recent years. Moreover, it is also difficult to reproduce a completely seamless plate when reprinting.

In the above-mentioned prior art, by adopting the digitized and mechanized processing for the work of the seamless operation, the work efficiency can be improved in the steps such as the joint of the images as compared with the above-mentioned prior art. . However, the seamlessness work itself has not been improved much in that it depends on the intuition and manual work of a skilled worker.

In the above-mentioned prior art, the efficiency has been improved by automating the work of making it seamless by digital processing. However, since the seamlessization simply adds (averages) the images on both sides at the joint, the high frequency component of the spatial frequency is lost near the joint, and the fine structure or sharpness of the image is reduced. Therefore, the problem remains that the joint is still recognized when viewed from a distance.

In view of the above points, according to the present invention, it is possible to create an image with high accuracy and inconspicuous seams, and at the same time, the skill of the operator and the manual work are unnecessary, and the processing efficiency is high, An object of the present invention is to provide an image correction method and system with excellent reproducibility.

[0011]

[Means for Solving the Problems]
Therefore, in the present invention, the edges of the same image are connected to the opposite edges.
Make sure the images are not conspicuous when you join them together.
Input the original image to be corrected as a correction method
Overlap at the image input stage and the joint part of the original image
Step of setting the amount of overlap, the set overlap
Creating an overlap region based on a quantity, said
The boundary of the edge part that is opposite to the edge part of the input original image is
The pixel value at the end and the pair in the overlap region
Based on the cumulative number of pixels with the smallest difference in pixel value
The step of determining, based on the determined boundary,
Modify the pixel values at the edges of the original image and at the opposite edges
By performing the step of creating a modified image
It is characterized by that.

According to the present invention, in the overlap area created based on the overlap amount in the joint portion of the original image, the boundary between the end portion and the end portion of the original image has a minimum difference in pixel value. Since the determination is made based on the accumulation of pixels, it becomes possible to create an image with no noticeable joint even when a plurality of images are arranged.

[0013]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. (1. System Configuration) First, the system configuration of the image correction system according to the present invention will be described. FIG. 1 is a system configuration diagram showing an embodiment of an image correction system. In FIG. 1, 1 is an original image inputting unit, 2 is an overlap amount setting unit, 3 is an arithmetic control unit, 3a is an overlap region creating unit, 3b is an optimum boundary determining unit, 3c is a pixel value correcting unit, 4 is an image. It is an output means.

The original image input means 1 is for inputting an original image to be subjected to seamless processing and endless processing, and is realized by reading the original image data with a digital data reading device. When the original image is drawn on a paper medium or the like, it is input after being digitized by using a scanner, a digital camera or the like. The overlap amount setting means 2 is for setting how much the end portion of the original image facing the end portion overlaps, that is, overlaps, and is realized by an input device such as a mouse and a keyboard.

The arithmetic and control unit 3 has a central role in the present invention, and makes both ends of the original image endless by correcting both ends of the original image based on the input original image and the set overlap amount. It has a function of creating a corrected image. Actually, it consists of the CPU and memory of the computer.
It is realized by sequentially executing the PU. The arithmetic and control unit 3 further has an overlap area creating unit 3a, an optimum boundary determining unit 3b, and a pixel value correcting unit 3c.
The overlap area creating means 3a has a function of calculating the size of the overlap area based on the size of the input original image and the set overlap amount, and ensuring a memory space of the calculated size. ing. The optimum boundary determining means 3b determines the optimum boundary of the other end portion that opposes the end portion of the original image based on the pixel value of the other end portion that opposes the pixel value of the end portion of the original image in the overlap area. It has the function of determining. The pixel value correction means 3c has a function of changing the pixel value on the original image based on the determined optimum boundary. The overlap area creating means 3a, the optimum boundary determining means 3b, and the pixel value correcting means 3c are realized by executing their own dedicated programs.
The image output unit 4 has a function of outputting the created corrected image, and has a display device for displaying the image, a printer for printing, an external storage device such as a hard disk for outputting as data, a portable device. A possible recording device for an electronic recording medium, a communication device for transmitting to a remote place via a network, and the like are applicable.

(2. Process Flow) Next, the image correction method according to the present invention will be described together with the processing operation of the image correction system shown in FIG. FIG. 2 is a flowchart showing the outline of the image correction method according to the present invention. First, the original image input means 1 inputs an original image to be subjected to endless processing (step S1). Next, the overlap amount setting means 2 is used to set the overlap amount (step S2). The overlap amount is an amount by which the end portions of the original image, which are opposed to the end portions, overlap each other, and the overlap region is determined based on this overlap amount. The overlap area is an area for determining an optimum boundary in the vicinity of the boundary between the edges of the original image and the edges of the original image. If this optimal boundary determination process is not performed, when a plurality of original images are arranged, a step becomes conspicuous at the boundary between them. In the present embodiment, the overlap amount is set by the number of pixels in which the end portions of the original image facing each other in one direction overlap each other.

Then, an overlap area is created based on the size of the input original image and the set overlap amount (step S3). Specifically, the overlap area creating means 3a secures a memory space required as an overlap area in the main storage device of the computer. For example, _{assume that} the size (the number of pixels) of the original image G _ORI is horizontal xp x vertical yp. At this time,
As shown in (b), when a plurality of original images G _ORI are arranged in the x-axis direction (horizontal direction in the figure), the length (number of pixels) of the side in contact with the adjacent original image G _ORI is yp. Assuming that the overlap amount is α, an overlap region O having a size of yp × α is created. Original image G processed by the present invention
_There is only one _ORI , and the left and right images when a plurality of them are arranged as shown in FIG. 3B are the same original image G _ORI ,
Here, for convenience of explanation, one is an original image G _L and the other is an original image G _R. As shown in FIG. 3B, an overlapping area having a size of yp × α is created across the original image G _L and the original image G _R.

After the overlap area is created, the optimum boundary between the original image G _L and the original image G _R in this overlap area is then determined (step S4). Specifically, in the overlap area, the minimum error boundary that minimizes the cumulative difference between the pixel values of the original image G _L and the original image G _R is obtained, and instead of the left side of the original image and the right side of the original image, ,
A process is performed in which the obtained minimum error boundary is the boundary between the original image G _L and the original image G _R. The obtained minimum error boundary is the optimum boundary.

Various methods have been proposed as methods for determining such a minimum error boundary. Therefore, Floyd and Dijks
A well-known algorithm such as tra algorithm may be applied, but the method in the present embodiment will be specifically described. Figure 4
Shows the vicinity of the overlap area O of the original image G _L and the original image G _R when the overlap amount α = 6. In the example of FIG. 4, since α = 6, six pixels are prepared in the overlap area in the x-axis direction (left and right direction in the drawing). In the case of such an overlap region, first
The pixel value of the original image G _{L and} the pixel value of the original image G _R are compared for the six pixels in the row. A value generally known as the L ² distance is used to calculate the position that minimizes the difference between the ^two . For example, in a certain pixel Q, the original image G Q pixel values corresponding to the pixels Q of the _{L L,} the pixel value corresponding to the pixel Q of the original image G _R When Q _R, L ² distance, the following [Equation 1].

[0020] [Formula 1] _{^{L 2 = (Q L - Q}} R) 2

When this value is calculated over the entire overlap area, this array becomes a map of the error just at that boundary. Therefore, L ² of each element on the way is accumulated for all the paths from the upper end (first row) to the lower end (the yp row) in this (6 × yp) pixel area, and this accumulation is performed. The route with the lowest cost (value)
It is the most preferable boundary. When the target image is color, the sum of the L ² values of the channels corresponding to each color is taken. In this way, the minimum error boundary is obtained by determining the path with the smallest accumulated cost (value).

When the optimum boundary is determined, the pixel value correcting means 3c corrects the pixel value of the original image based on the determined optimum boundary (step S5). For example, consider a case where the minimum error boundary as shown in FIG. 5 is obtained in the overlap region. In FIG. 5, the shaded pixel is the minimum error boundary. In this case, the pixel on the left side of the minimum error boundary adopts the pixel value of the original image G _L ,
The pixel value on the right side of the minimum error boundary adopts the pixel value of the original image G _R. Further, in the present embodiment, for the pixels existing on the minimum error boundary, the average of the pixel values of the original image G _L and the original image G _R is taken. In FIG.
The pixel value of the original image G _L is “R” for the pixel indicated by “L”.
Pixels indicated by indicate that the pixel values of the original image G _R are given respectively. When the corrected image is obtained by correcting the pixel value of the original image, the image output means 4 outputs it (step S6).

Here, the outline of the method of obtaining the minimum error boundary will be summarized. An outline of how to find the minimum error boundary is shown in the flowchart of FIG. In order to obtain the minimum error boundary, first, the L ² value in each pixel for all the pixels in the first row (6 pixels in the example in the figure) is stored as a cumulative cost (step S11). Then, for each pixel in the second row, the one with the smallest accumulated cost for the upper left, directly above, and upper right pixels of itself is stored as the shortest path to this pixel, and the accumulation of the upper pixel is performed. The sum of the cost and the L ² value of itself is stored as the cumulative cost of itself (step S12). The process of step S12 is repeated up to the last line, that is, the yp-th line in the examples of FIGS. Of all the pixels in the last row, the pixel having the smallest accumulated cost and the path leading to the pixel are set as the minimum error boundary (step S13).

As a result, the optimum boundary B as shown in FIG. 7A is obtained in the overlap area O shown in FIG. 3B. In FIG. 7A, the optimum boundary B
The pixel value of the original image G _R is given to the right side of the, and the pixel value of the original image G _L is given to the left side of the optimum boundary B. Intuitively, this is an image in which, when the original images are arranged in the x-axis direction, instead of the rectangular original images, the images separated by the optimum boundaries as shown in FIG. 7B are arranged. However, FIG.
As shown in (b), it is not realistic that the shape of the image is the curve shown by the optimum boundary. Actually, delete the overlap area on one side (eg right side) of the original image,
Pixel values on the right side of the optimum boundary of the area are copied to the corresponding left side overlap area. Specifically, FIG.
As shown in (c), the pixels in the region indicated by the original image G _ORI of P _L, P _R 'in the copied pixels of the region indicated that the region indicated by the original image G _ORI of P _R and P _R The area marked with 'will be deleted. That is, in the above description, for the sake of convenience of description, the two images are arranged side by side as shown in FIG. 3B, but in reality, both ends of one original image (FIG. 3A). Also, in the example of FIG. 7C, the pixel values at the left and right ends are corrected and deleted. By arranging a plurality of corrected images obtained in this way in the x-axis direction, the joints become inconspicuous.

In the above example, when a plurality of original images are arranged in the x-axis direction, the image is corrected so as to be an endless image. However, even when a plurality of original images are arranged in the y-axis direction, the x-axis and the y-axis are arranged. The axes are simply swapped, and essentially the same process is performed. Further, when the images are arranged in both the x-axis direction and the y-axis direction, the image correction processing is performed in both the x-axis direction and the y-axis direction, so that even when the images are arranged two-dimensionally in the vertical and horizontal directions. It is possible to obtain a corrected image in which all joints are inconspicuous.

In the above example, the case where a plurality of the same images are lined up has been described. However, a plurality of images having the same side length (number of pixels) to be connected are sequentially connected so that the joints are not conspicuous, and the left end is connected. It is also possible to create a seamless image by connecting the left end portion of the image and the right end portion of the right end image at the optimum boundary in the same manner in the overlap region. For example, the correction process is performed by using different images as the original image G _R and the original image G _L in FIGS. 3B and 7A.

[0027]

As described above, according to the present invention,
Input the original image to be corrected so that it becomes an endless image, set the overlap amount with the adjacent original image, create an overlap area based on the set overlap amount, and The boundary between the end portion and the end portion facing the end portion is determined based on the accumulation of pixels in which the difference between the pixel value of the end portion and the pixel value of the opposite end portion in the overlap region is minimum, and based on the determined boundary. Since the endless image is created by correcting the pixel value at the end of the original image, it is possible to create an image in which the seams are not conspicuous even when a plurality of images are arranged. .

[Brief description of drawings]

FIG. 1 is a configuration diagram of an image correction system according to the present invention.

FIG. 2 is a flowchart of an image correction method according to the present invention.

3 is a diagram showing the relationship between the overlap region O of the case of arranging plural original images G _ORI, and the original image G _ORI.

FIG. 4 is a diagram showing the vicinity of an overlap region O.

FIG. 5 is a diagram showing the vicinity of an overlap area O after determining an optimum boundary.

FIG. 6 is a flowchart showing an outline of how to find a minimum error boundary.

FIG. 7 is a diagram showing a state of a corrected image obtained by determining an optimum boundary.

[Explanation of symbols]

1. Original image input means 2 ... Overlap amount setting means 3 ... Arithmetic control device 3a ... Overlap area creating means 3b ... Optimal boundary determining means 3c ... Pixel value correction means 4 ... Image output means

Claims (3)

[Claims] 1. A method for correcting an image so that the seam is not conspicuous when the opposite ends of the same image are joined to each other, and an image for inputting an original image to be corrected is input. An input step, a step of setting an overlap amount in a joint portion of the original image, a step of creating an overlap area based on the set overlap amount, and a step of facing an end portion of the input original image. The boundary of the
A step of determining based on accumulation of pixels in which a difference between a pixel value of the end portion and a pixel value of the opposite end portion in the overlapping area is minimum, and based on the determined boundary, An image correction method comprising: a step of creating a corrected image by correcting pixel values at an end portion and an opposite end portion. 2. An original image input means for inputting an original image to be corrected, an overlap amount setting means for setting an overlap amount in a joint portion of the original images, and an overlap amount based on the set overlap amount. An overlap area creating means for creating an overlap area, and a boundary between the edges of the input original image and the edges facing each other,
Optimal boundary determining means for determining based on accumulation of pixels in which the difference between the pixel value of the end portion and the pixel value of the opposite end portion in the overlap region is minimum, and based on the determined boundary, An image characterized by comprising: a pixel value correcting means for creating a corrected image by correcting the pixel values of the end portion of the original image and the opposite end portion; and an image output means for outputting the obtained corrected image. Correction system. 3. An image input step of inputting an original image to be corrected to a computer, a step of setting an overlap amount at a joint portion of the original image, and an overlap based on the set overlap amount. A step of creating a region, and a boundary of an end portion facing the end portion of the input original image,
A step of determining based on accumulation of pixels in which a difference between a pixel value of the end portion and a pixel value of the opposite end portion in the overlapping area is minimum, and based on the determined boundary, A program for executing the steps of creating a corrected image by correcting the pixel values at the edge and the opposite edge.