JP2013135365A - Image processing device, image processing method, and program - Google Patents

Abstract

In an image processing apparatus that displays an original image in a reduced size, adjusts the image quality on a display, and outputs the image to a device larger than the display, the appearance differs depending on the size of the output device even though the image is the same. End up.
An adjustment unit that adjusts an image quality parameter of an image, an image quality change unit that changes an image quality of an input image based on the adjusted image quality parameter, and an image that outputs the image with the changed image quality to the outside Output means, image reduction means for reducing the image whose image quality has been changed, and image display means for displaying the reduced image, wherein the image reduction means reduces the image according to the image reduction rate. An image processing apparatus characterized by reducing the high-frequency component is provided.
[Selection] Figure 6

Description

  The present invention relates to an image processing apparatus, an image processing method, a program, and a computer-readable storage medium storing the program for adjusting an image quality parameter related to the image quality in radiographic imaging technology.

  A system is used in which an image quality parameter related to the image quality of an image is adjusted while a user looks at a monitor screen to print the image. Many of these systems are devised so that the color of the monitor screen and the color of the printed material are the same as in Patent Document 1. However, when the monitor screen is small and the printed material is large compared to this, even if the color is the same, the atmosphere of the image adjusted on the monitor screen and the atmosphere of the image of the printed material are often different, resulting in an uncomfortable feeling. This is because the image adjusted on the monitor screen has sharp details such as the fine structure, but the printed image does not have sharp details. This is because the frequency increases when the image is reduced.

  With reference to FIG. 1, it will be described that the frequency increases when a printed matter that is a full-size display is reduced and displayed on the monitor screen. Figure 1 shows the case where the size of the printed material and the monitor screen is 3: 1. The relationship between the size of the printed material and the monitor screen is shown in FIG. 1A, and the state when the sine wave having the printed material width as one cycle is reduced to the size having the monitor screen width as one cycle is shown in FIG. (b). As can be seen from FIG. 1 (b), the amplitude is the same even when reduced, but the frequency is high. In this case, the frequency is three times higher. As described above, when the full-size display is reduced and displayed on the monitor screen, the frequency of the entire image is increased. Therefore, an image that has been adjusted on the monitor screen has high sharpness. However, since the full-size display has a lower sharpness than an image that has been adjusted on the monitor screen, the atmosphere of both images is different and an uncomfortable feeling occurs.

  In the field of radiographic images, a 14-inch × 17-inch film called a half-cut size is used as printed matter, and it is required to output the film without impairing the atmosphere of the image adjusted on the monitor screen. Only when the film is output, the user notices that the sharpness is insufficient, and returns to the adjustment work, so that the sharpness must be set higher on the monitor screen and output again, resulting in poor work efficiency.

JP 2006-262471 A JP 2000-076431

  Japanese Patent Application Laid-Open No. 2004-228688 is an invention that aims to make the atmosphere of an image that has been adjusted on the monitor screen the same as the atmosphere of a printed image. The present invention is an apparatus having a conversion unit that prepares two image quality parameters for reduced display and image quality parameters for output, and converts the parameters so that they are visually equivalent. The configuration of this apparatus is, for example, FIG. 2, and the conversion unit is R112 '. However, when the number of image quality parameter items is large, it is not easy to determine a conversion rule that is visually equivalent. First, it is assumed that the reduction ratio is determined and the number of items is one (for example, noise reduction). Assuming that the effect of noise reduction is 10 levels, the rule for converting 10 levels for reduced display to 10 levels for output is not simply doubled or 1/4 times. While comparing the output display, the conversion rule is determined so that it is visually equivalent. Next, consider the case where the number of items is two. Each item of the image quality parameter is rarely visually independent. If each item has 10 levels, visually compare the 10 × 10 = 100 combinations while comparing the reduced display and the output display. Conversion rules are determined so that they are equivalent to each other. Similarly, if the number of items is N and each item has A stages, a conversion rule that visually equates must be found for A ^ N combinations. Thus, when there are a large number of items of image quality parameters, it is difficult to determine conversion rules that are visually equivalent.

  Further, the conventional apparatus changes the image quality parameter in relation to the reduction ratio and resolution. In order to be visually equivalent, the distance of image observation and the size of the image should be considered. FIG. 3 is a luminance distribution on the monitor screen when images are displayed on the monitor 1 and the monitor 2 arranged at two different distances. The monitor 1 is at a distance r1 from the observer's eyes, and the width of the screen is y1. The monitor 2 is at a distance r2 from the observer's eyes, and the width of the screen is y2. The monitor 2 displays an image in full size, and the monitor 1 displays a reduced size. The relationship between r1, y1, r2, and y2 is r1: y1 = r2: y2. The luminance distribution is similar in the width direction, and the maximum luminance value is the same. In the case of this relationship, the atmosphere of the image displayed on the monitor 1 and the atmosphere of the image displayed on the monitor 2 are substantially the same. If the resolution of the monitor 1 is at least r2 / r1 times the resolution of the monitor 2, the image of the monitor 1 and the image of the monitor 2 cannot be visually distinguished.

  Here, the resolution of the monitor is the number of pixels per unit length. It is the reciprocal of the length of one pixel. If the length and the number of pixels of the image displayed on the image display unit are known, calculation is possible. For example, when an image of 100 × 100 pixels is displayed on a liquid crystal monitor with a size of 1 cm × 1 cm, the resolution is 100 [/ cm]. Even if the image is displayed in a reduced size as shown in FIG. 3, there is a case where it is visually equivalent even if the image quality parameter is not changed depending on the situation of image observation.

  In view of the problems described above, an object of the present invention is to provide an apparatus in which the atmosphere of an image that has been adjusted on a monitor screen is the same as the atmosphere of an image of a printed matter.

  In order to achieve the above object, the present invention includes an adjusting unit that adjusts an image quality parameter of an image, an image quality changing unit that changes an image quality of an input image based on the adjusted image quality parameter, and the image quality is changed. Image output means for outputting the reduced image to the outside, image reduction means for reducing the image whose image quality has been changed, and image display means for displaying the reduced image, wherein the image reduction means Provided is an image processing apparatus characterized by reducing a high-frequency component of an image to be reduced according to a reduction ratio.

  According to the present invention, it is possible to make the atmosphere of the image that has been adjusted on the monitor screen and the atmosphere of the printed image the same without imposing a special burden on the user.

It is a figure explaining a frequency becoming high if an image is reduced. It is a functional block diagram of the image processing apparatus of a prior art. It is a figure showing the positional relationship of the monitor when an angle of view is the same. 1 is an overall configuration diagram of an image processing system according to an embodiment of the present invention. It is a functional block diagram of the image generation apparatus in the system of FIG. 1 is a functional block diagram of an image processing apparatus according to Embodiment 1. FIG. 3 is a flowchart illustrating an operation of the image processing apparatus according to the first exemplary embodiment. It is explanatory drawing of image display adjustment GUI. It is a supplementary figure for demonstrating an example of the characteristic of a high frequency reduction filter. It is explanatory drawing of the test pattern displayed on a monitor. FIG. 6 is a functional block diagram of an image processing apparatus according to a second embodiment. 10 is a flowchart illustrating an operation of the image processing apparatus according to the second exemplary embodiment. FIG. 10 is a functional block diagram of an image processing apparatus according to a third embodiment. 10 is a flowchart of image reduction processing in the third embodiment. FIG. 10 is a functional block diagram of an image processing apparatus according to a fourth embodiment. 10 is a flowchart of image reduction processing in Embodiment 4.

  FIG. 4 shows the overall configuration of the image processing system according to the embodiment of the present invention. In FIG. 4, the computer PC is connected to one or a plurality of image generation devices MD via a network N. Alternatively, the present invention can be applied in exactly the same manner even if an image photographed by a photographing apparatus (not shown) is stored in the file server FS in advance and can be handled equally as an image generating apparatus. In FIG. 4, the image generating device MD is connected to the computer PC via the network N, but may be connected not via the network. For example, the computer PC and the image generation device MD may be connected by a one-to-one direct connection. The image generation device MD will be described as an image generation device R500 in FIG.

  The computer PC includes a CPU, RAM, ROM, hard disk HD, hardware accelerator ACC, and bus BUS. Further, the magneto-optical disk MO, mouse MS, keyboard KB, printer PR, and display device MON are connected to the computer PC.

  FIG. 5 shows a configuration of the image generation device R500. The X-ray generation unit R501 emits X-rays, and the irradiated X-rays pass through the subject, further pass through the grid R502, and reach the X-ray sensor unit R503. The X-ray sensor unit R503 acquires an X-ray image by converting the reached X-ray into an electric signal. Next, a logarithmic conversion unit (not shown) attached to the X-ray sensor unit converts the X-ray image into a logarithmic image, and outputs this logarithmic image from the image generation device R500. The output logarithmic image is input to an image processing apparatus R100 described later.

<Example 1>
FIG. 6 illustrates functional blocks of the image processing apparatus R100 according to the first embodiment. The image processing apparatus R100 can be realized by the computer PC and its peripheral devices shown in FIG. As an example, the image processing device R100 can be realized as a program stored in the hard disk HD and the display device MON. In this case, a program stored in a storage device (hard disk HD, RAM, or ROM) is read into the RAM by a user input (not shown), and the CPU sequentially executes the programs in the RAM to realize each function. The result of the image processing is displayed on the display device MON. Here, for example, a CRT monitor, a liquid crystal display, or the like can be used as the display device MON. The program need not be limited to being stored in an internal storage device such as the hard disk HD, but can be stored in a magneto-optical disk MO connected to a computer PC or a file server FS connected via a network as an external storage device. You may be made to do. Further, the image processing apparatus R100 may be realized as a dedicated hardware accelerator ACC that is partially or entirely mounted on the computer PC.

  FIG. 7 is a flowchart illustrating the operation of the image processing apparatus according to the present embodiment. In the following, the function of each block in FIG. 6 will be described in the order of the flowchart in FIG. Each step in FIG. 7 is stored in a storage device (such as a hard disk HD) of a computer PC, and the CPU of the computer PC reads out a program describing the operation of each step and executes it in the order of flowcharts.

  The process of FIG. 7 is triggered by the user pressing an unillustrated X-ray irradiation button connected to the image generation apparatus R500 of FIG. First, in step S101, the X-ray sensor unit R503 obtains an X-ray image by converting the X-rays irradiated by the X-ray generation unit R501 of FIG. 5 and reaching the X-ray sensor unit R503 into an electrical signal. Next, a logarithmic conversion unit (not shown) attached to the X-ray sensor unit converts the X-ray image into a logarithmic image, and outputs this logarithmic image from the image generation device R500. The output logarithmic image becomes an input image of the image processing apparatus R100.

  In step S102, the image quality change processing unit R110 changes the image quality of the image input to the image processing apparatus R100 in step S101 based on the image quality parameter set by the image display adjustment GUI unit R140 in FIG. Is output. In this embodiment, the image display adjustment GUI unit R140 adjusts the image quality parameter for controlling the image quality and the geometric conversion parameter for controlling the geometric conversion of the image display. In the example shown in FIG. 8, the image quality parameters are brightness, contrast, sharpness, softness, noise removal, and edge enhancement. The geometric transformation parameters are zoom magnification and rotation. Hereinafter, a parameter group combining the image quality parameter and the geometric conversion parameter is referred to as an “image display parameter”.

  In step S103, the image reduction processing unit R200 reduces the image 1 and outputs the image 2. The image reduction processing unit R200 first removes the aliasing component by the aliasing removal filter R201 based on the zoom magnification set by the image display adjustment GUI unit. Next, based on the zoom magnification, a high frequency component is removed by the high frequency reduction filter R202. Finally, the image is thinned out by the thinning processing unit R203 to create a reduced image. Here, the aliasing removal filter R201 must be executed before the thinning processing unit R203. On the other hand, the high frequency reduction filter R202 may be executed before or after the thinning processing unit R203, or may be executed before or after the aliasing removal filter R201. In this embodiment, the zoom magnification and the reduction ratio are used interchangeably. When the zoom magnification is 0.1, the reduction ratio is 0.1, and when the zoom magnification is 1.0, the reduction ratio is 1.0. A reduction ratio of 1.0 means that the image is not reduced, and a reduction ratio of 0.1 means that the number of pixels on the side is converted to 1/10 while maintaining the vertical and horizontal aspect ratio of the image. Yes. For example, when the size of the image 1 is 100 × 100 pixels and the reduction ratio is 0.1, the size of the image 2 is 10 × 10 pixels.

  Here, the role of the high frequency reduction filter R202 is to suppress an increase in high frequency components caused by the reduction process. As specifically explained using FIG. 1 in the background art section, when the reduction ratio is 1/3, the frequency component of the image (frequency component of the printed matter) is tripled in the high frequency direction by the reduction process. Get higher. Therefore, even though the images are the same, the atmosphere of the images differs depending on whether or not to reduce the display. In order to make the atmosphere substantially the same, high frequency components are suppressed by a high frequency reduction filter. The closer the reduction ratio is to 1.0, the higher the cutoff frequency of the high frequency reduction filter, and the closer the reduction ratio is to 0, the lower the cutoff frequency. The cut-off frequency may be changed based on the subject in the image. For example, the subject information may be acquired, and the cutoff frequency characteristics may be changed based on the subject as shown in FIGS.

  In step S104, the image display unit R130 displays the image 2. In this embodiment, the size of the image for displaying the image 2 on the image display unit is adjusted by the user using the image display adjustment GUI unit R140. However, this size may be fixed. In this case, the reduction ratio is fixed, and the zoom magnification adjustment GUI of the image display adjustment GUI unit R140 is not displayed.

  In step S105, the process waits until the parameter of the image display adjustment GUI unit R140 changes or the output is instructed. The process proceeds from step S105 to step S106 when the user operates the image display adjustment GUI unit R140 to change the parameter or when the user instructs the output.

  In step S106, it is determined whether output is instructed. When the output is not instructed, the parameter of the image display adjustment GUI unit R140 has changed, and the process returns to step S102 to change the image quality of the image. If output is instructed, the process proceeds to step S110.

  In step S110, the image output unit R120 adds attribute information to the image 1 and outputs it as an output image to the external device R300, and the processing in FIG. 7 ends. Here, the attribute information is, for example, the number of vertical and horizontal pixels, DICOM attribute information in a medical image, and accompanying information related to the image.

  It is desirable that the relationship between the luminance corresponding to the image gradation when observing the image 1 and the relationship between the luminance corresponding to the image gradation when displaying the image on the image display means are visually the same. . If the device for observing the image 1 is the device 1 and the image display means is the device 2, it can be paraphrased as follows. It is desirable that the luminance relationship corresponding to the image gradation of the device 1 and the luminance relationship corresponding to the image gradation of the device 2 are visually the same.

  Here, the relationship between the luminance corresponding to the image gradation of the device 1 and the luminance relationship corresponding to the image gradation of the device 2 is visually the same. The case of displaying will be described. FIG. 10A shows the appearance of the image. Each area in FIG. 10A is defined as A, B, C, and D as shown in FIG. 10B. “Visually the same” means that the stimulus amount that perceives the luminance difference between region A and region B is E1, and the stimulus amount that perceives the luminance difference between region C and region D is E2. Say the state. If the gradation of the image in FIG. 10A is A = 0, B = 100, C = 100, and D = 200, E1: E2 = 1: 1. Since the stimulation amount is the same, if the device 1 can perceive the region B, it means that the device 1 can also perceive the region D. Furthermore, if the device 2 can perceive the region B, it means that the region D of the device 2 can also be perceived. Human visual characteristics differ depending on whether the surroundings are dark or bright, and a small luminance difference can be perceived when it is dark, but when it is bright, it cannot be perceived unless the luminance difference is large. Therefore, a state of “visually the same” can be created when there is a certain relationship in luminance corresponding to the image gradation.

  For example, as shown in FIG. 10 (c), a display of the same size, a minimum luminance of 0 [cd / m ^ 2], a display 1 with a maximum luminance of 300 [cd / m ^ 2], and a minimum luminance of 0 [cd / m ^ 2 ] Assume that there is a display 2 with a maximum brightness of 500 [cd / m ^ 2]. In this case, it is possible to alleviate the uncomfortable feeling related to the image gradation by creating the “visually the same” state. The relationship of luminance corresponding to image gradations that can create a “visually identical” state is, for example, a Barten curve. Barten curves are often used in medical image display. In addition, the device in the case of observing the image 1 includes not only a light emitter device such as a display but also an observation device such as a combination of a film and a Schaukasten.

<Example 2>
FIG. 11 is a functional block diagram of an image processing apparatus R100 according to the second embodiment. FIG. 12 is a flowchart illustrating the operation of the image processing apparatus according to the present embodiment. Blocks having the same reference numerals in the drawings in the first embodiment and the present embodiment mean that they are the same, and a part of the description is omitted because of the space on the drawing. Hereinafter, differences from the first embodiment will be described in the order of the flowchart of FIG.

  First, after acquiring an image in step S101 as in the first embodiment, the first image reduction processing unit R200 reduces the image and outputs an image 2 in step S101 '. Next, in step S102 ', the second image quality change processing unit R102 changes the image quality of the reduced image and outputs it as the image 3 to the image display unit R130. With this configuration, the image 3 displayed on the image display unit R130 can be displayed at a higher speed than the image display of the first embodiment. The processing in steps S104 to S106 is the same as that in the first embodiment. The image quality change of the image acquired in step S101 is executed in step S109. In step S109, the image processing unit R101 changes the image quality of the image and inputs it as the image 1 to the image output unit R120. The processing in step S110 is the same as that in the first embodiment.

<Example 3>
FIG. 13 is a functional block diagram of the image processing apparatus according to the third embodiment. 7 and 14 are flowcharts showing the operation of the image processing apparatus according to the present embodiment. Blocks having the same reference numerals in the drawings in the first embodiment and the present embodiment mean that they are the same, and a part of the description is omitted because of the space on the drawing. Hereinafter, differences from the first embodiment will be described in the order of flowcharts in FIGS. 7 and 14.

  In this embodiment, the image reduction process (step S103 in FIG. 7) in the first embodiment is executed as shown in the flowchart of FIG. Other processes are the same as those in the first embodiment.

  First, in step S201, the sharpness calculation unit R152 calculates the sharpness of the image 1, and inputs the calculated sharpness to the filter calculation unit R150. Here, the sharpness is a ratio of a high frequency component per unit area in the image display device. The image display device includes not only a light emitter device such as a display but also an observation device such as a combination of a film and a Schaukasten. The sharpness calculation unit R152 calculates the sharpness based on the resolution 1 of the image display device of the output image and the output image. The sharpness calculation is, for example, “(1) Apply a high-pass filter to the image, (2) Add the absolute value of the pixel value of the image of the high-pass filter output, and (3) Output the amount per unit area” There is a method. Alternatively, the sharper the image, the wider the distribution of pixel values, so the sharpness may be calculated using entropy as an index.

  In step S202, an initial value of the filter coefficient of the high frequency reduction filter R202 'is given. This value can be anything, but it is desirable that the cut-off frequency be increased as the reduction ratio increases. In step S203, the image reduction processing unit R200 'outputs the image 2 to the image display unit R130. The high frequency reduction filter R202 'of the image reduction processing unit R200' performs high frequency reduction processing using the filter coefficient given in step S202. In step S204, the sharpness calculation unit R151 calculates the sharpness of the image 2. The resolution 2 of the image display unit R130 is input to the sharpness calculation unit R151, the sharpness is calculated by the same calculation as in step S201, and the calculated sharpness is input to the filter calculation unit R150.

  In step S205, the filter calculation unit R150 calculates the difference in sharpness between the image 1 and the image 2, and determines whether the difference is within a predetermined range. If the difference is not within the predetermined range, the process proceeds to step S206. If the difference is within the predetermined range, the process arrives at the “end” in the flowchart of FIG. 14 and proceeds to S104 of FIG.

  In step S206, the filter calculation unit R150 calculates the filter coefficient of the high frequency reduction filter R202 '. This filter coefficient is calculated so that the sharpness of image 1 and the sharpness of image 2 match. When the sharpness of the image 2 is larger than the sharpness of the image 1, the filter coefficient is calculated so that the cutoff frequency of the high frequency reduction filter is lower than the current cutoff frequency. When the sharpness of the image 2 is smaller than the sharpness of the image 1, the filter coefficient is calculated so that the cutoff frequency of the high frequency reduction filter is higher than the current cutoff frequency. The calculated filter coefficient is given to the high frequency reduction filter R202 ', and the process returns to step S203. Note that it is technically difficult to completely match the sharpness of image 1 and the sharpness of image 2, and therefore, in step S205, if the difference is within a predetermined range, it is determined that they are almost the same. The process proceeds to the next process.

  In this embodiment, since the high frequency reduction filter corresponding to the reduction ratio is automatically calculated, the work of determining the cutoff frequency of the high frequency reduction filter for each reduction ratio becomes unnecessary.

<Example 4>
FIG. 15 is a functional block diagram of an image processing apparatus according to the fourth embodiment. 7 and 16 are flowcharts illustrating the operation of the image processing apparatus according to the present embodiment. The blocks having the same reference numerals in the drawings in the first embodiment, the third embodiment, and the present embodiment mean that they are the same, and a part of the description is omitted because of the space on the drawing. Hereinafter, differences from the first and third embodiments will be described in the order of the flowcharts of FIGS. 7 and 16.

  In this embodiment, the image reduction process (step S103 in FIG. 7) in the first embodiment is executed as shown in the flowchart of FIG. Other processes are the same as those in the first embodiment.

  First, in step S301, the angle of view 1 for observing the output image is input from the angle of view input unit (not shown) to the filter calculation unit R160. In step S302, the angle of view 2 when the image 2 is observed on the image display unit R130 is input from the angle of view input unit (not shown) to the filter calculation unit R160. In step S303, the filter calculation unit R160 calculates a filter coefficient and outputs the filter coefficient to the high frequency reduction filter R202 '. Here, the process reaches the “end” in the flowchart of FIG. 16 and proceeds to S104 of FIG.

  Here, when the angle of view 1 and the angle of view 2 are the same, this corresponds to a situation in which the image 2 is reduced and displayed on the monitor 1 and the output image is displayed on the monitor 2 in the positional relationship of FIG. Since the observer cannot distinguish between the two, the atmosphere of the image is the same. Therefore, when the angle of view 1 and the angle of view 2 are the same, the filter coefficient is calculated so that the high frequency reduction filter does not work. For example, the same filter coefficient as the impulse response is given. Alternatively, for example, a filter coefficient that makes the cutoff frequency of the high frequency reduction filter sufficiently high may be given. When the angle of view 2 is narrower than the angle of view 1, a filter coefficient is provided so that the cutoff frequency of the high frequency reduction filter is lowered. When the angle of view 2 is wider than the angle of view 1, the filter coefficient is calculated so that the high frequency reduction filter does not work. In this embodiment, when the angle of view 2 is wider than the angle of view 1, the high frequency reduction filter is not used, but the image 2 may be sharpened by a high frequency enhancement filter (not shown).

<Other examples>
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (13)

Adjusting means for adjusting the image quality parameter of the image;
Image quality changing means for changing the image quality of the input image based on the adjusted image quality parameter;
Image output means for outputting the image having the changed image quality to the outside;
Image reduction means for reducing the image whose image quality has been changed;
Image display means for displaying the reduced image;
The image processing apparatus according to claim 1, wherein the image reduction means reduces a high frequency component of an image to be reduced in accordance with a reduction rate of the image.   The image quality-changing image and the reduced image further include means for calculating a sharpness indicating a ratio of a high-frequency component per unit area, and the image reduction means includes the two calculated sharpness values. The image processing apparatus according to claim 1, wherein a high-frequency component of an image to be reduced is reduced so that the two are equal.   The image processing apparatus further includes means for inputting an angle of view for observing each of the image with the changed image quality and the reduced image, and the image reducing means has an image to be reduced according to the two input angles of view. The image processing apparatus according to claim 1, wherein a high frequency component is reduced. Adjusting means for adjusting the image quality parameter of the image;
Image quality changing means for changing the image quality of the input image based on the adjusted image quality parameter;
Image output means for outputting the image having the changed image quality to the outside;
Image reduction means for reducing the input image;
Second image quality changing means for changing the image quality of the reduced image based on the adjusted image quality parameter;
Image display means for displaying an image whose image quality has been changed by the second image quality changing means;
The image processing apparatus according to claim 1, wherein the image reduction means reduces a high frequency component of an image to be reduced in accordance with a reduction rate of the image.   The relationship between the luminance corresponding to the image gradation when observing the image with the changed image quality and the relationship between the luminance corresponding to the image gradation when displaying the image on the image display means are visually the same. The image processing apparatus according to claim 1, wherein the image processing apparatus is provided.   The apparatus further includes means for inputting subject information of the input image, the image reducing means further includes a high frequency reduction filter, and a filter coefficient of the high frequency reduction filter is changed according to the input subject information. The image processing apparatus according to claim 1, wherein the image processing apparatus is characterized.   The image processing apparatus according to claim 2, wherein the means for calculating the sharpness calculates the sharpness using entropy.   The image processing apparatus according to claim 1, wherein the input image is an X-ray image.   6. The image processing apparatus according to claim 3, wherein a film is observed when the image with the changed image quality is observed.   6. The image processing apparatus according to claim 5, wherein the luminance relationship corresponding to the image gradation is a Barten curve. An adjustment step for adjusting the image quality parameter of the image;
An image quality changing step for changing the image quality of the input image based on the adjusted image quality parameter;
An image output step of outputting the image with the changed image quality to the outside;
An image reduction step for reducing the image whose image quality has been changed;
An image display step for displaying the reduced image;
In the image reduction method, the high frequency component of the image to be reduced is reduced in accordance with the reduction ratio of the image. An adjustment step for adjusting the image quality parameter of the image;
An image quality changing step for changing the image quality of the input image based on the adjusted image quality parameter;
An image output step of outputting the image with the changed image quality to the outside;
An image reduction step for reducing the input image;
A second image quality changing step for changing the image quality of the reduced image based on the adjusted image quality parameter;
An image display step for displaying an image whose image quality has been changed by the second image quality change step;
In the image reduction method, the high frequency component of the image to be reduced is reduced in accordance with the reduction ratio of the image.   The program for functioning a computer as each means as described in the image processing apparatus of any one of Claims 1-10.

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