JPH0689336A - Image data enlarging and displaying method - Google Patents

Abstract

PURPOSE:To improve the efficiency of respective enlarging processes according to enlargement rates of an image by generating enlarged image data by linear interpolation arithmetic for a small enlargement rate or by nonlinear interpolation arithmetic if deterioration in picture quality causes trouble because of a large enlargement rate. CONSTITUTION:A threshold value for enlargement decision making which is previously set in a main memory 10, etc., is read in. Then, an operator selects which of original images stored in a storage device 1 is enlarged and displayed by using a keyboard 2. In this state, an enlargement rate is found and it is decided whether or not the enlargement rate is larger than the read threshold value for enlargement decision making. When the enlargement rate is smaller than the threshold value, a high-speed arithmetic circuit 5 enlarges data on the respective original images by the linear interpolation. When the enlargement rate is larger than the threshold value, on the other hand, the high-speed arithmetic circuit 5 enlarges the data on the respective original images by the nonlinear interpolation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for enlarging and displaying image data by an interpolation operation in an image workstation or the like, and particularly, to use both linear interpolation operation and non-linear interpolation operation depending on the size of the enlargement ratio. The present invention relates to an image data enlargement display method capable of efficiently enlarging and displaying image data.

[0002]

2. Description of the Related Art Conventionally, in order to magnify and display image data by an interpolation calculation in an image workstation or the like, a method of expanding by linear interpolation calculation and a method of expanding by nonlinear interpolation calculation have been used. As shown in FIG. 5, the linear interpolation calculation uses the known pixel values of four points A, B, C, and D around the pixel α at the point α of the image to obtain the pixel value at the point α. This is to obtain an approximate value. Further, in the non-linear interpolation calculation, as shown in FIG. 6, when the pixel value of a certain point β of the image is obtained, the known pixel values of, for example, 16 points A, B, C, ... It is used to obtain the approximate value of the pixel value at the point β. When the linear interpolation calculation is used, the calculation time is short, but the image quality deteriorates when the enlargement ratio increases. Also, when non-linear interpolation calculation is used,
Although the image quality of the enlarged image was good, the calculation time was long.

[0003]

However, in the conventional image data enlargement display method in an image workstation or the like, either the enlargement method by the linear interpolation calculation or the enlargement method by the nonlinear interpolation calculation is used. There was only one. Therefore, in the case of using the expansion method by the linear interpolation calculation, the expansion rate is 3
Although it is good up to about twice, if the enlargement ratio is larger than that, the image quality of the obtained enlarged image deteriorates and becomes difficult to see. Further, in the case of using the enlargement method by the non-linear interpolation calculation, a long calculation time is required even if the enlargement ratio is small and the deterioration of the image quality is not a serious problem. From this, whichever interpolation method is used for enlargement, the efficiency at the time of enlargement may decrease depending on the situation of the enlargement ratio.

Therefore, the present invention copes with such a problem and selectively uses both the linear interpolation calculation and the non-linear interpolation calculation depending on the size of the image enlargement ratio to efficiently enlarge and display the image data. An object of the present invention is to provide a method for enlarging and displaying image data.

[0005]

In order to achieve the above object, the image data enlargement display method according to the present invention obtains the enlargement ratio from the size of the original image and the image size after the enlargement, and the enlargement ratio is obtained. Is smaller than a predetermined magnification, linear interpolation calculation is performed on the original image data to create enlarged image data, and if the enlargement ratio is larger than a predetermined magnification, nonlinear interpolation calculation is performed on the original image data. The original image is enlarged and displayed by creating enlarged image data and displaying these enlarged image data.

[0006]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a flow chart showing the procedure of an image data enlargement display method according to the present invention, and FIG. 2 is a block diagram showing an example of the configuration of an image workstation used for implementing the image data enlargement display method. In FIG. 2, the storage device 1 is an external device such as an X-ray CT device or M
A large number of medical images that have been detected and created by an RI apparatus or the like regarding a diagnostic region of a subject are input and stored, and are composed of a magnetic tape or a magnetic disk. Keyboard 2
Is an input device for inputting operation commands such as calling of an image from the storage device 1 and designation of a display mode. Also,
The mouse 3 is an input device for inputting position information and the like from the outside, and is controlled by the controller 4.
The high-speed arithmetic circuit 5 performs arithmetic processing such as interpolation on the image data read from the storage device 1. The CRTs 6a and 6b are display devices that display the image data read from the storage device 1 and the calculation result of the high-speed calculation circuit 5. Further, the printer 7 is the C
The images displayed on the RTs 6a and 6b are printed on a film or the like, and are connected via an interface 8. The CPU 9 is a central processing unit that controls the entire image workstation. The main memory 10 stores data and information necessary for the control operation by the CPU 9, and is directly addressed by the CPU 9. In FIG. 2, reference numeral 11 is a data bus.

Next, the procedure of the present invention will be described with reference to FIGS. First, in the storage device 1 of the image workstation shown in FIG. 2, as shown in FIG. 3, for example, a large number of medical images I ₁ , I ₂ ,
It is assumed that I ₃ , ... Is recorded. Then, these medical images I ₁ , I ₂ , I ₃ , ... Are enlarged and displayed as original images. The original image has a size of 512 × 512 pixels, and the enlarged image has a size of 4300 × 5000 pixels, for example. And
In such a state, the threshold value for determining the enlargement ratio set in advance in the main memory 10 in FIG. 2 is read (step in FIG. 1). Here, as the threshold value, for example, “magnification factor of 3” is used.

Next, the operator uses the keyboard 2 shown in FIG. 2 to input the original images I ₁ , I ₂ , stored in the storage device 1.
Of the I ₃ , ..., Which image is to be enlarged and displayed is selected and its display mode is designated (step). Here, the display style means the enlarged images Ia, Ib, I shown in FIG.
In c, after enlarging the original image, the enlarged image size 430
It shows how many divisions are displayed within an area of 0 × 5000 pixels. In the first enlarged image Ia, the display is divided into 20 and displayed in the second enlarged image Ib. The third enlarged image Ic is divided into two and displayed. Now, assume that 20 original images are selected and the display style is specified as 20 divisions. That is, it is assumed that it is specified that the image is enlarged and displayed in the state of the first enlarged image Ia.

Next, the enlargement ratio is obtained in this state (step). At this time, as shown in FIG. 3, the size of the original image is 512 × 512 pixels, and the size of the enlarged image is 4300 × 5000.
This is a pixel, and this enlarged image is divided into 20 and displayed. Therefore, when calculated from these numerical values, the enlargement ratio of the image in this case is approximately twice. Then, it is determined whether or not the enlargement ratio of the image obtained as described above is larger than the threshold value for enlargement ratio determination read in step (step).

Now, the enlargement ratio obtained in step is about 2
Since the threshold value for determining the enlargement ratio is 3 times,
The step proceeds to the "NO" side. Then, the high-speed operation circuit 5 shown in FIG. 2 enlarges the data of each original image by the linear interpolation operation shown in FIG. 5 (step). As a result, enlarged image data is created, so that the image is sent to the CRT 6a or 6b shown in FIG. 2 and the first enlarged image Ia is displayed on the screen as shown in FIG. 3 (step). In this case, the enlarged image data created above is used for the interface 8
It may be sent to the printer 7 via the, and the printer 7 may print on a film or the like.

Next, in the above step, it is assumed that six original images are selected and the display style is designated as six divisions.
That is, it is assumed that it is specified that the second enlarged image Ib in FIG. 3 is enlarged and displayed. Then, when the enlargement ratio is obtained in this state (step), since the enlarged image of 4300 × 5000 pixels is divided into six and displayed this time,
When calculated from these numerical values, the magnification ratio of the image in this case is about 3.3 times. Therefore, the determination as to whether the value is larger than the threshold value for the enlargement ratio determination in the step is “YE
Then, the process proceeds to the S ″ side. Therefore, this time, the high-speed arithmetic circuit 5 shown in FIG. 2 also enlarges the data of each original image by the non-linear interpolation operation shown in FIG. 6 (step). Therefore, it is sent to the CRT 6a or 6b shown in FIG. 2 and the second enlarged image Ib is displayed on the screen as shown in FIG. 3 (step).

In the above step, assuming that two original images are selected and the display mode is designated as two divisions like the third enlarged image Ic shown in FIG. 3, the enlargement ratio in this case is about 5. It doubles (step), and the step also goes to the “YES” side. And also in this case,
The high-speed arithmetic circuit 5 shown in FIG. 2 may enlarge (step) the data of each original image by a non-linear interpolation operation.

FIG. 4 is an explanatory view showing a modified example of the operation when the original image is enlarged and displayed on the same CRT 6a or 6b of the image workstation shown in FIG. First,
In FIG. 4, one medical image I ₁ is displayed as an original image on the screen of the CRT 6a. Next, an enlargement frame Ix (shown by a broken line) indicating the enlargement display range including the two sides of the medical image I ₁ is displayed. Then, an arrow 12 interlocked with the operation of the mouse 3 is displayed at the corner portion of the enlarged frame Ix facing the corner where the original image (I ₁ ) is located. In this state, the mouse 3 is operated to move the arrow 12 to an arbitrary position to enlarge the original image (I ₁ ) and set the enlargement frame Ix of a size desired to be displayed. As a result, the procedure corresponding to the steps of the flowchart shown in FIG. 1 has been executed. After that, the enlargement ratio of the image is obtained by calculation from the region of the original image (I ₁ ) and the region of the enlargement frame Ix in FIG. 4 (step). The procedure thereafter is exactly the same as the flowchart shown in FIG. 1, and the enlarged image is displayed.

[0014]

Since the present invention is constructed as described above,
When the magnification of the image is smaller than the predetermined magnification, linear interpolation calculation is performed on the original image data to create enlarged image data, and when it is larger than the predetermined magnification, non-linear interpolation calculation is performed on the original image data. By creating the enlarged image data, if the enlargement ratio is small and the deterioration of the image quality is not a problem, the calculation time can be shortened by using the linear interpolation calculation. If the enlargement ratio is large and the deterioration of the image quality becomes a problem. Even if the calculation time is long, the image quality of the enlarged image can be kept good by using the nonlinear interpolation calculation. Therefore, according to the present invention, the efficiency at each enlargement can be improved according to the situation of the enlargement ratio of the image.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of an image data enlarged display method according to the present invention,

FIG. 2 is a block diagram showing a configuration example of an image workstation used for carrying out the image data enlarged display method.

FIG. 3 is an explanatory view schematically showing the procedure of the image data enlarged display method of the present invention,

4 is the same C of the image workstation shown in FIG.
Explanatory drawing which shows the modification of operation in the case of enlarging and displaying the original image on RT,

FIG. 5 is a diagram for explaining a method of linear interpolation calculation;

FIG. 6 is a diagram for explaining a method of nonlinear interpolation calculation.

[Explanation of symbols]

1 ... Storage device, 2 ... Keyboard, 3 ... Mouse, 5
... Fast arithmetic circuit, 6a, 6b ... CRT, 7 ... printer, 9 ... CPU, 10 ... main memory, I ₁ ~I ₄ ... original image (medical image), Ia to Ic ... enlarged image.

Claims (1)

[Claims] 1. A magnified image is obtained from the size of the original image and the image size after the desired enlargement. If the magnified image is smaller than a predetermined magnification, a linear interpolation operation is performed on the data of the original image to enlarge the enlarged image. If data is created, and if the enlargement ratio is greater than a predetermined magnification, non-linear interpolation calculation is performed on the original image data to create enlarged image data, and the original image is enlarged by displaying these enlarged image data. A method for enlarging and displaying image data, which is characterized by displaying as.