JP3647261B2 - Image processing apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus and method thereof, and more particularly to an image processing apparatus and method for generating a mosaic image.
[0002]
[Prior art]
According to Sanseido's “Contemporary Language Dictionary”, mosaic is “a combination of small pieces of stone, glass, marble, etc. of various colors, fitted on floors, walls, etc., and designed, or its technique”. By using this technique, it is possible to compose a design or one image (mosaic image) by combining a large number of photographic images. In the image processing, the generation of the mosaic image is achieved by dividing the design or image that is the basis of the image into tiles and pasting the material image most similar to the tile image onto the tile area.
[0003]
[Problems to be solved by the invention]
However, the above-described technique has the following problems.
[0004]
That is, the same material image may be affixed to a plurality of divided tile areas. And in the area | region where the same material image concentrated in the produced | generated mosaic image, a texture generate | occur | produces with the material image and there exists a problem that the pattern which the base design or image does not intend is made.
[0005]
The present invention is intended to solve the above-described problem, and an image processing apparatus and method for preventing generation of an unintended texture when generating a mosaic image and generating a higher-quality mosaic image The purpose is to provide.
[0006]
[Means for Solving the Problems]
The present invention has the following configuration as one means for achieving the above object.
[0007]
An image processing method according to the present invention is an image processing method for forming a mosaic image by combining a plurality of material images, and divides an image on which the mosaic image is based into M × N regions, determined image characteristics of the area, the area selected random order, based on the image characteristics of the selected region, as one of the material image does not correspond to overlap in a plurality of regions, sequentially, corresponding to the selected area The material image to be determined is determined.
[0008]
An image processing apparatus according to the present invention is an image processing apparatus that generates a mosaic image by combining a plurality of material images, and stores an input unit that inputs an image serving as a basis of the mosaic image, and the plurality of material images. region storage means, an original image inputted is divided into regions of M × N, and dividing means asking you to image characteristics of each divided region, and selecting means for selecting the area in random order, which is the choice to based on the image characteristics, as a material image does not correspond to overlap in a plurality of regions, sequentially, and having a determining means for determining a material image corresponding to the selected region.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
[0010]
[Mosaic image generation method]
FIG. 1 is a diagram showing the relationship between a plurality of types of images used in a mosaic. In FIG. 1, a first image 201 is a design or an image (for example, a photographic image, a computer graphics image, or the like) that is a basis for constructing an image with a mosaic. The second image 202 is an image composed of mosaics. The material image 203 is used to construct the second image 202. In general, the number P of material images 203 is a sufficiently large number that can prepare colors and textures necessary for forming the second image 202.
[0011]
In FIG. 1, for ease of explanation, the size of the material image 203 is the same as that of the tile. However, the size of the material image 203 and the tile does not necessarily match, and the material image 203 is all the same size. There is no need. However, when the size of the material image 203 is different from that of the tile, the size of the material image 203 may be resized to the tile size when the material image 203 is pasted on the corresponding tile area. In addition, the shape of the tile is not limited to a rectangle, and may be any shape. When the material image 203 is pasted on the tile area, the shape of the material image 203 may be cut or deformed to be shaped into a tile shape.
[0012]
Next, a method for constructing an image using a mosaic will be described with reference to FIG.
[0013]
In step S211 of FIG. 2, the first image 201 is divided into M × N tiles. As a result, for example, as shown in FIG. 3, 4 × 5 rectangular tiles TL (0,0), TL (0,1), TL (0,2), ..., TL (4,2), TL ( 4,3) is generated.
[0014]
In FIG. 3, X and Y represent the number of pixels in the horizontal and vertical directions of the first image 201, respectively, and p and q represent the number of pixels in the horizontal and vertical directions of each divided tile. Therefore, the relationship X = p × M, Y = q × N holds. FIG. 4 is a diagram showing the configuration of individual tiles. Each tile is decomposed into a plane of p × q pixels of three primary colors, red, green, and blue.
[0015]
Subsequently, in step S212, an RGB average luminance value is calculated for each of the divided M × N tiles according to the following equation.
Rd_av = ΣRi / (p × q)
Gd_av = ΣGi / (p × q)
Bd_av = ΣBi / (p × q)
[0016]
In step S213, an RGB average luminance value is calculated for each of the P material images 203 according to the following equation.
Rs_av = ΣRi / (p × q)
Gs_av = ΣGi / (p × q)
Bs_av = ΣBi / (p × q)
[0017]
In step S214, counters X_Pos (0 ≦ X_Pos ≦ M−1) and Y_Pos (0 ≦ Y_Pos ≦ N−1) indicating the position of the tile being processed are both initialized to zero. Note that (X_Pos, Y_Pos) = (0, 0) indicates the tile position of the upper left corner of the first image 201.
[0018]
Next, in step S215, the material image 203 most suitable for the tile indicated by the counter (X_Pos, Y_Pos) is selected. In this selection method, the distance ΔE based on the RGB tristimulus values between the average luminance value of the tile and the average luminance value of the material image 203 is calculated, and the material image 203 having the smallest ΔE is selected. When the selected material image 203 is pasted on the tile area, if the size does not match, the scaling process is performed so that the size becomes an appropriate size.
ΔE = (Rs_av-Rd_av) ^ 2 + (Gs_av-Gd_av) ^ 2 + (Bs_av-Bd_av) ^ 2
Where a ^ 2 represents the square of a.
[0019]
Subsequently, in step S216, the counter (X_Pos, Y_Pos) is sequentially counted up or down in the horizontal and vertical directions, and steps S215 to S217 are repeated until the processing of step S215 is performed on all tiles based on the determination in step S217. .
[0020]
Therefore, when tiles having the same average luminance value or very close to each other are present in the tiles divided into M × N, the same material image 203 is selected and pasted on those tile areas. For this reason, in the region where the same material image 203 is concentrated in the generated mosaic image, a texture due to the material image 203 is generated, and an unintended pattern is generated in the generated image 202.
[0021]
In order to avoid the above problem, a method of not pasting the material image 203 pasted on a certain tile area to another tile area is also conceivable. According to this method, it is possible to prevent unintended texture generation. However, since the material image 203 is pasted from the upper left tile of the first image 201 to the lower right tile without using the same material image 203, there are many in the upper left area of the first image 201. Although the material image 203 that is relatively close to the average luminance value of the tile image can be selected from the material images 203 of the first image 201, the material image 203 that can be used is reached in the lower right region of the first image 201. It is difficult to select the material image 203 whose number is reduced and which is close to the average luminance value of the tile image. Therefore, the mosaic image generated in this way has a problem that the image quality is different between the upper left area and the lower right area.
[0022]
[Method of forming a mosaic image in this embodiment]
FIG. 5 is a block diagram illustrating a configuration example of an image processing apparatus that generates a mosaic image according to the embodiment of the present invention.
[0023]
In FIG. 5, a reading unit 100 is, for example, a scanner for reading an image. The accumulation unit 101 is for accumulating and managing images in a storage medium such as a hard disk, and constitutes an image database, for example. The display unit 102 is a CRT or LCD monitor for displaying images stored in the storage unit 101 or images read by the reading unit 100.
[0024]
The CPU 103 controls the entire image processing apparatus according to a program stored in advance in the ROM 104 and is involved in all of the above processes. The RAM 105 is used as a work memory by the CPU 103.
[0025]
In addition to the above, the image processing apparatus of the present embodiment is provided with various components, but those configurations are not the main part of the present invention, and thus description thereof is omitted.
[0026]
Next, mosaic image generation processing in the image processing apparatus of this embodiment will be described with reference to the flowchart of FIG.
[0027]
In step S300 of FIG. 6, the first image 201 is divided into M × N tiles. As a result, for example, as shown in FIG. 3, 4 × 5 rectangular tiles TL (0,0), TL (0,1), TL (0,2), ..., TL (4,2), TL ( 4,3) is generated.
[0028]
In step S301, an RGB average luminance value is calculated for each of the divided M × N tiles according to the following equation.
Rd_av = ΣRi / (p × q)
Gd_av = ΣGi / (p × q)
Bd_av = ΣBi / (p × q)
[0029]
Next, in step S302, an RGB average luminance value is calculated for each of the P material images 203 according to the following equation. Note that image characteristics such as the RGB average luminance value of the material image 203 can be obtained in advance. In that case, the image characteristics may be recorded as header information of the material image 203, or may be recorded in a table corresponding to the material image 203 stored in the storage unit 101.
Rs_av = ΣRi / (p × q)
Gs_av = ΣGi / (p × q)
Bs_av = ΣBi / (p × q)
[0030]
Next, in step S303, all the used flags of the P material images 203 are turned off. This processed flag indicates whether or not the corresponding material image 203 is pasted on the first image 201. At step S303, since no material image 203 has been selected or pasted yet, the used flag of all P material images 203 is reset to OFF.
[0031]
Next, in step S304, data indicating the random processing order of tiles is stored in the array T_Turn [M · N−1]. The array stores data such that when T_Turn [] = K, the quotient of K / (M-1) indicates the Y coordinate and the remainder indicates the X coordinate. A method for storing the random processing order of tiles in the same array will be described with reference to the flowchart of FIG.
[0032]
In FIG. 7, in step S500, T_Turn [0] = 0, T_Turn [1] = 1, T_Turn [2] = 2,..., T_Turn [M · N−1] = M · N-1 Store. Next, M · N−1 is set to the counter i in step S501, and a random number R from 1 to i is generated in step S502.
[0033]
Then, in step S503, the data stored in T_Turn [R] and T_Turn [i] are replaced according to the generated random number R, the counter i is decremented (i = i-1) in step S504, and i ≧ in step S505. If 0, the process returns to step S502, and if not, the data exchange is terminated.
[0034]
In this way, data for processing tiles in random order is stored in the array T_Turn [M · N−1].
[0035]
Next, in step S305 in FIG. 6, the counter j is reset to 0, and in step S306, the material image 203 having the closest average luminance value to the tile image specified by T_Turn [j] is selected. Here, the material image 203 that becomes a selection candidate is limited to those with the used flag set to OFF. For example, when T_Turn [j] = 0, the tile position is (0,0), indicating the upper left tile. In this selection method, the distance ΔE based on the RGB tristimulus values between the average luminance value of the tile and the average luminance value of the material image 203 is calculated, and the material image 203 having the smallest ΔE is selected. When the selected material image 203 is pasted on the tile area, if the size and shape do not match, scaling processing and shaping processing are performed so as to obtain an appropriate size and shape.
ΔE = (Rs_av-Rd_av) ^ 2 + (Gs_av-Gd_av) ^ 2 + (Bs_av-Bd_av) ^ 2
[0036]
Next, in step S307, the used flag corresponding to the material image 203 selected and pasted on the first image 201 is set to ON so that the material image 203 is not pasted on another tile area. To do. In step S308, the counter j is incremented, and while j <M × N holds according to the determination in step S309, the processing in steps S306 to S308 is executed, and the material image 203 is pasted on all tiles.
[0037]
As described above, according to this embodiment, a material image selected once is not used again in one mosaic image, and an appropriate material image is selected by selecting tiles in a random order. By sticking, it is possible to prevent the occurrence of unintended textures and to homogenize the image quality of the entire mosaic image, thereby generating a higher-quality mosaic image.
[0038]
[Other Embodiments]
Note that the present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), or a device (for example, a copier, a facsimile device, etc.) including a single device. You may apply to.
[0039]
Another object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium Needless to say, this can also be achieved by reading and executing the program code stored in the. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.
[0040]
Further, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted in the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an image processing apparatus and method for generating a mosaic image with higher image quality while preventing generation of an unintended texture when generating a mosaic image.
[Brief description of the drawings]
FIG. 1 is a diagram showing a relationship between a plurality of types of images used in a mosaic;
FIG. 2 is a flowchart for explaining a method for constructing an image using a mosaic;
FIG. 3 is a diagram showing a state in which a base image is divided into M × N tile areas;
FIG. 4 is a diagram showing the configuration of individual tiles;
FIG. 5 is a block diagram illustrating a configuration example of an image processing apparatus that generates a mosaic image;
FIG. 6 is a flowchart illustrating an example of mosaic image generation processing;
FIG. 7 is a flowchart illustrating a processing example for randomizing the processing order of tiles.

Claims (10)

An image processing method for forming a mosaic image by combining a plurality of material images,
Dividing the image on which the mosaic image is based into M × N regions,
Find the image characteristics of each divided area,
Select the regions in random order,
Based on the image characteristics of the selected region, as one of the material image does not correspond to overlap in a plurality of regions, sequentially, an image processing method characterized by determining the elemental image corresponding to the selected area.   2. The image processing method according to claim 1, wherein the determination of the correspondence between the region and the material image is to select a material image having an image characteristic closest to the image characteristic of the region.   3. The image processing method according to claim 1, wherein a mosaic image is generated by pasting a corresponding material image on each of the regions.   4. The image processing method according to claim 1, wherein the correspondence between the region and the material image is determined using a flag corresponding to each of the material images.   5. The image processing method according to claim 4, wherein the flag is set when a corresponding material image is associated with the region.   6. The image processing method according to claim 1, further comprising calculating image characteristics of the plurality of material images.   7. The image processing method according to claim 1, wherein the image characteristic is an average luminance value of a plurality of pixels forming the region or material image.   7. The image processing method according to claim 1, wherein the image characteristic is an average luminance value for each color component of a plurality of pixels forming the region or material image. An image processing apparatus that generates a mosaic image by combining a plurality of material images,
Input means for inputting an image as a basis of the mosaic image;
Storage means for storing the plurality of material images;
Dividing the inputted original image in a region of the M × N, and dividing means asking you to image characteristics of each divided area,
Selection means for selecting the regions in random order ;
Based on the image characteristics of the selected region, and one of the material image is duplicated in a plurality of areas so as not to correspond sequentially; and a determining means for determining a material image corresponding to the selected region An image processing apparatus. Controls the image processing apparatus, a recording medium in which a program for executing the image processing according to any of claims 1 to 8, characterized in that it is recorded.

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