JPH0997330A - Method and device for image enlargement processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an enlargement processor for medical images which is shortened in arithmetic processing time. SOLUTION: The image enlargement processor which adds n×n (n: integer larger than 4) adjacently arranged pixel data together after multiplying them by a coefficient calculated by a specific calculating method to interpolate pixels nearly by the center of the n×n pixel data has an image memory (1) 11 which stores previously an image to be enlarged, and an enlargement information input means 12, an arithmetic control means 10, a coefficient table memory 14, and an image memory (2) 16 through which image data size of enlargement and enlargement power are set; and the arithmetic control means 10 stores the result of calculation by the specific calculating method in the coefficient table memory 14, calls the coefficient out of the coefficient table memory 14 when respective interpolation pixels are calculated to perform an interpolation processing, and inputs an enlarged image to the image memory (2) 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image enlargement processing method and apparatus, and more particularly to an image enlargement processing method and apparatus suitable for enlarging a medical image.

[0002]

2. Description of the Related Art As a general method for enlarging a medical image, n × n (n is a value of an integer of 4 or more) pixel data arranged adjacent to each other is multiplied by a coefficient calculated using a non-linear function. Then, enlargement processing is used in which pixels near the center of the n × n pixel data are interpolated by adding. The non-linear function is a spline function of 3rd order or higher selected by the distance between the interpolated pixel and each n × n pixel, and the distance between the interpolated pixel and each n × n pixel is passed to the spline function as a parameter. Then, the coefficient is calculated. That is, the following calculation is performed as a general method for obtaining the interpolated pixel S (x, y) from the 4 × 4 pixel value indicated by the black circle in FIG.

[0003]

[Equation 1]

Where

[0005]

[Equation 2]

Since the processing time is slightly shortened, Japanese Patent Laid-Open No.
There is a proposal according to Japanese Patent No. 7584. In this proposal, the above calculation is not performed for each interpolation pixel, but the calculation is performed with n pixel data in one vertical and horizontal direction, and the calculation result is used to perform interpolation with n pixel data in the other direction. Interpolation calculation of S (i, y) = S (i, j−1) × F (j−1−y) + S (i, j) × F (j−y) + S (i, j + 1) × F (j + 1-y) + S (i, j + 2) * F (j + 2-y) Interpolation calculation in the X direction S (x, y) = S (i-1, y) * F (i-1-x) + Interpolation calculation of S (i, y) * F (i-y) + S (i + 1, y) * F (i + 1-x) + S (i + 2, y) * F (i + 2-x) is performed.

[0007]

According to the conventional method, the coefficient calculation is performed by multiplying the number of vertical pixels after enlargement × the number of horizontal pixels after enlargement × n × n.
It has a drawback that it has to be performed once and takes a long processing time. Further, the proposal by Japanese Patent Laid-Open No. 5-7584 is also not sufficient, though the processing time is shortened as compared with the conventional method. It is another object of the present invention to provide an image enlarging processing method and apparatus capable of reducing the calculation processing time.

[0008]

The above object is to multiply each pixel data of n × n (n is an integer value of 4 or more) arranged adjacently by a coefficient calculated by a predetermined calculation method, and then add the pixel data. Thus, in the image enlargement processing method of interpolating a pixel near the center of the n × n pixel data, the coefficient is calculated in advance according to a predetermined calculation method and stored in the coefficient table, and when calculating each interpolation pixel, the coefficient is calculated from the coefficient table. Image enlarging processing method, characterized in that
A pixel is interpolated in the vicinity of the center of the n × n pixel data by multiplying each of the pixel data of × n (n is a value of an integer of 4 or more) by a coefficient calculated by a predetermined calculation method and adding the result. In the image enlargement processing device, the image enlargement processing device stores an image to be enlarged in advance in an image memory (1)
And an enlargement information input means for setting an image data size to be enlarged and an enlargement ratio, an operation control means, a coefficient table memory and an image memory (2), and the operation control means outputs a result calculated according to a predetermined calculation method. An image enlargement processing device characterized by storing in a coefficient table memory, calling a coefficient from the coefficient table memory at the time of interpolation calculation, performing interpolation processing, and outputting an enlarged image to the image memory (2). .

[0009]

The present invention is image enlargement in which each of n × n pixel data is multiplied by a coefficient calculated by a predetermined calculation method and added to interpolate, and n × n coefficients are not calculated for each interpolated pixel. By referring to the coefficient calculated by the predetermined calculation method and stored in the coefficient table and reducing the number of times the coefficient is calculated, the interpolation processing time can be shortened.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an example of an image enlarging processing apparatus of the present invention. An image memory (1) 11 stores original image data to be enlarged in advance. Enlarged information input means 12
Is input the image data size to be enlarged and the enlargement ratio,
The image data size and the enlargement ratio are set in the arithmetic control unit 10. The arithmetic control means 10 performs the following pre-processing from the setting information.

The number of vertical pixels after enlargement and the number of horizontal pixels after enlargement are calculated, and n coefficients are calculated per pixel for one larger line and stored in 14 coefficient table memories. Further, the number of vertical pixels after enlargement and the number of horizontal pixels after enlargement are obtained, and the correspondence between the larger one line and the pixel data coordinates of the original image is calculated and stored in the coordinate table memory.

When the preprocessing is completed, the arithmetic control means carries out the following interpolation processing.

Counter (1) 17 and counter (2) 18
Reset. In the image memory (1) 11, a read address is designated by a value read by using the counter (2) 18 and the counter (1) 17 of the coordinate table as an address, and n pixels arranged vertically adjacent to the arithmetic control unit 10. The data is read and the counter (1) 17 of the coefficient table is read.
A predetermined calculation is performed with the value read with the address as the address and written in the working memory 15. The working memory 15 is a memory having the size of the number of pixels in the horizontal direction of the original image, and the counter (1) 17 is counted up to repeat the above calculation for the number of pixels in the horizontal direction of the original image. When the working memory 15 stores data of several pixels in the horizontal direction of the original image, the counter (1) 17 is reset.

The working memory 15 uses the counter (1) 17 of the coordinate table as the address to specify the read address, and the n pixel data arranged side by side in the horizontal direction are read by the arithmetic control means 10 and the coefficient is also read. A predetermined operation is performed by using the value read with the counter (1) 17 of the table as an address, and the counter (1) 17 and the counter (2) 18 are written in the image memory (2) 16 as the writing address.
The counter (1) 17 is counted up and the above calculation is repeated several times in the horizontal direction of the enlarged image. Image memory (2) 1
When the data of several horizontal pixels of the enlarged image is stored in 6, the counter (1) 17 is reset and the counter (2) is reset.
Count up 18. The above calculation process is repeated while the counter (2) 18 is smaller than the number of vertical pixels of the enlarged image.

The above-mentioned pre-processing and the complementary processing which is subsequently performed are described below according to the processing procedure.

The symbols used here are as follows.

Mag Enlargement ratio LX Number of input image X pixels LY Number of input image Y pixels Img Input image memory LX 'Enlarged image X image prime LX × Mag LY' Enlarged image Y image prime LY × Mag Img 'Enlarged image memory Length LX' , LY 'whichever is larger Address [Length] Coordinate table memory Distance [Length] [4] Coefficient table memory Temp [LX] Interpolation midway data table C1 Counter 1 C2 Counter 2 Preprocessing (calculation of coefficients and coordinates used for interpolation) ) LX 'and LY' are compared and the larger one is found Leng
Set the value to th.

The pixel coordinates of the original image are calculated from the enlarged image coordinates.

-1 Set 0 to C1.

-2. Pixel coordinate calculation method of original image Address [C1] = C1 / Mag ... Truncate to a decimal place after the decimal point. -3. Compare C1 and Length to check the end.

If C1 <Length, the process branches to -2.

If C1 ≧ Length, the process branches after calculation of pixel coordinates of the original image.

A coefficient is calculated from the interpolation position.

-1 Set 0 to C1.

-2 coefficient calculation setting

[0026]

(Equation 3)

-3 C1 and Length are compared to check the end.

If C1 <Length, it branches to -2.

If C1 ≧ Length, the preprocessing is terminated.

Interpolation processing 0 is set in C2.

0 is set in C1.

A one-column interpolation midway calculation is performed from Img in the Y direction.

-1 Img pixel read position P2 ... Address [C2] * LX + C1-2 Interpolation midway calculation method

[0034]

[Equation 4]

-3 Add 1 to C1.

-4 C1 and LX are compared to check the end of one column.

If C1 <LX, the process branches to -1.

If C1 ≧ LX, the process branches at the end of one column.

0 is set in C1.

Interpolation calculation is performed in the X direction from Temp.

-1 Temp data read position P
1 Address [C1] −2 Img ′ image writing position P2 ... C2 + C
1 × LX ′ -3 interpolation calculation method

[0042]

(Equation 5)

-4 Add 1 to C1.

-5 C1 and LX 'are compared to check the end of one column.

If C1 <LX ', it branches to -1.

If C1 ≧ LX ', the process branches at the end of one column.

Add 1 to C2.

The end of interpolation is checked by comparing C2 and LY '.

If C2 <LY ', the process branches.

If C2 ≧ LY ', the interpolation is completed.

[0051]

As described above, according to the present invention, the calculation of the coefficient, which conventionally required a long processing time, can be performed only by the number of pixels having a larger number of vertical pixels and horizontal pixels after enlargement × n times. An image enlargement processing method and apparatus capable of high-speed processing are provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between pixels and interpolation pixels.

[Explanation of symbols]

 10 arithmetic control means 11 image memory (1) 12 enlarged information input means 13 coordinate table memory 14 coefficient table memory 15 working memory 16 image memory (2) 17 counter (1) 18 counter (2)

Claims (4)

[Claims] 1. The n × n pixel is obtained by multiplying each of the n × n (n is an integer value of 4 or more) pixel data arranged adjacent to each other by a coefficient calculated by a predetermined calculation method and adding the result. In an image enlargement processing method of interpolating pixels near the center of data, a coefficient is calculated in advance according to a predetermined calculation method and stored in a coefficient table, and an image is obtained from the coefficient table when calculating each interpolation pixel. Enlargement processing method. 2. The image enlarging processing method according to claim 1, wherein the pixel data coordinates of the interpolated image used in the interpolation are stored in the coordinate table in advance in correspondence with the pixel data coordinates of the enlarged image. . 3. The n × n pixels by multiplying each of n × n (n is an integer value of 4 or more) pixel data arranged adjacent to each other by a coefficient calculated by a predetermined calculation method and adding the multiplied values. In an image enlargement processing device for interpolating pixels near the center of data, the image enlargement processing device is set with an image memory (1) in which an image to be enlarged is stored and an image data size to be enlarged and an enlargement ratio. It has an information input means, a calculation control means, a coefficient table memory and an image memory (2), the calculation control means stores the result calculated according to a predetermined calculation method in the coefficient table memory, and the interpolation table calculates from the coefficient table memory. An image enlargement processing apparatus, characterized in that a coefficient is called to perform an interpolation process and an enlarged image is output to an image memory (2). 4. The image enlargement according to claim 3, further comprising a coordinate table memory for storing pixel data coordinates of an interpolated image used in the interpolation in advance in correspondence with pixel data coordinates of the enlarged image. Processing equipment.