JP2003189180A - Radiant ray image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiant ray image processing apparatus that adopts the digital radiography system needing only one exposure and eliminates the need for many experiences, trial-and-error, and complicated operations. <P>SOLUTION: The radiant ray image processing apparatus includes: an image read means that reads a radiant ray image obtained by emitting a radiant ray to a subject; a storage means that stores image information by the image read; an image display means that displays information from the image read means and/or the storage means; an image position designation means that optionally designates an in-screen area of the image display means; and a means for revising a density of a designated area in the screen, interlocking with the designation by the image position designation means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to improvement of a radiation diagnostic apparatus. More specifically, the present invention relates to a device for outputting a designated image as a proper image by means of a radiation image information reading unit having a wide dynamic range, a region designating unit in an image, an image density numerical value displaying unit and an image density changing unit.

[0002]

2. Description of the Related Art It is widely known that there is a radiographic apparatus as a means for imaging the inside of a subject and contributing to diagnosis, and it is well known that a large amount of radiation exposure adversely affects the subject. Although various measures can be considered to reduce the amount of radiation exposure, as an effective means in recent years, the recording of radiation transmitted light is performed not on the silver halide photosensitive material but on the stimulable phosphor, the reading means, the display, and the printout. A radiation image processing apparatus in which the means are connected has been proposed.

To explain this background in a little more detail, when photographing on a silver halide light-sensitive material which has been performed for a long time, the image density displayed on the silver halide light-sensitive material is limited to 0 to 3 or so. Therefore, in order to see the necessary area with proper density and contrast, it is necessary to have a photographic technique based on abundant experience, and if the exposure amount is not appropriate, the image information of the necessary area becomes unreadable. Since the photosensitive material becomes useless, the exposure condition is changed again and the image is taken again.

However, repeating photography is an act that must be avoided because it adversely affects the subject, especially the human body.
Improvement was called for. The stimulable phosphor system has been developed as a means for responding to this. An image detector (image reading means) using a stimulable phosphor has a wide dynamic range and can obtain a linear digital signal with respect to a wide range of radiation intensity. Since an image signal sufficiently containing necessary subject information can be obtained for the condition, the photographing can be completed only once.

However, the stimulable phosphor system is still under development and cannot be put to practical use in the medical field unless various problems are solved and a good system is used.

[0006] One of the problems is that there is no method for properly displaying and printing out the information of the site necessary for diagnosis. Now, if the entire image signal in a wide range as described above is visualized and expressed corresponding to, for example, a density range that can be printed out on a silver halide photosensitive material and a luminance range that can be reproduced by an image display means (CRT or the like). , The displayed image has too low a contrast to visually recognize the information necessary for diagnosis, and it is inevitable that the information necessary for diagnosis is easily visible in the area necessary for diagnosis. Image signal processing and gradation conversion processing must be performed so that the density (or brightness) range and gradation (contrast) will vary, which requires a complicated system and the experience and labor of the operator. This is not preferable. As a countermeasure, a method has been proposed in which the necessary parts are designated in advance and the photographing method is specified, and the computer automatically determines and executes the gradation conversion processing of the image, but even this countermeasure is not always the optimum processing. May not be performed. It is also clear that it is not suitable for diagnosing the part deviating from the designation.

Further, in Patent Document 1, a user (operator) uses an image display parameter and a keyboard (input means) for image processing parameters such as gradation processing and frequency processing for image signals accumulated by photographing. Although it is shown that the parameters are set, the process of determining the parameters to be specifically set is not shown.
In the following description, it is slightly shown that the user examines the quality of the visualized image, including the doctor, and resets the parameters again depending on the examination result. This means that the description is based on the assumption that the operator performs trial and error or has abundant experience in setting (or inputting) the image processing parameter, and that the development has never been advanced. Does not indicate.

[0008]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2-278471

[0009]

In view of the above-mentioned drawbacks of the prior art, a digital radiography system that requires only one exposure to radiation is employed, and a great deal of experience, trial and error is not required, and it is complicated. It is an object of the present invention to provide a radiation image processing device that does not require operation.

[0010]

In order to achieve the above object, the present invention has the following means. (A) Image reading means for reading a radiation image obtained by irradiating a subject with radiation, storage means for storing image information by the image reading means, and information from the image reading means and / or the storage means Image display means, image position designating means for arbitrarily designating a screen area of the image display means, and means for changing the density of the designated area in the screen in association with the designation by the image position designating means. And a radiation image processing apparatus. (B) The radiation image processing apparatus according to (a), further comprising image density value display means for displaying the output density equivalent value of the designated area by a numerical value. (C) has a visual image output means for printing out,
The radiation image processing apparatus according to (a), which prints out at an image density corresponding to the output density value of the designated area. (D) has a visualized image output means for printing out and a density designating means for designating the image density of the designated area,
The radiation image processing apparatus according to (a), wherein the image density of the designated area is printed out at the designated density. (E) The radiation image processing apparatus according to (a), wherein the means for changing the output density of the image display means has a function of gradation conversion. (F) The radiation image processing apparatus according to (a), wherein the image display means has a function of displaying a density scale for displaying the output density as a sample. (G) Size specified by the image position specifying means /
The radiation image processing apparatus according to (a), wherein the shape can be changed.

[0011]

The image reading means using the stimulable phosphor has a wide dynamic range and can obtain a linear digital signal with respect to the intensity of radiation in a wide range. That is, the characteristic curve of the silver halide light-sensitive material is different from that of the S-shaped characteristic curve.

Displaying the output density equivalent value as a numerical value for an arbitrarily designated area in the screen area means that the average density or median value of the area is converted into a value in the output density range 0 to 3 and displayed. Means that.

This is for outputting the 12-bit digital data of 0-4095, which has a wide dynamic range of the image reading means, while converting it to a density of 0-3 to improve the recognition of the density. Is.

This has the effect of making it easier to recognize the deviation between the average density or median value and the median value of the output print density that is easy to see.

Then, density conversion is performed to expand the maximum density and the minimum density of a portion other than the average value or the median value in the designated area to a range of 3 to 0.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, X-rays will be described as an example of radiation.

In FIG. 1, X-rays from an X-ray irradiating device 1 including an X-ray tube and the like pass through a subject 2 and are applied to a radiation conversion panel 3. The radiation conversion panel 3 has a stimulable phosphor layer, and when this phosphor is irradiated with excitation light such as X-rays, electron beams, and ultraviolet rays, a part of its energy is changed depending on the irradiation amount. Accumulated. As a result, the radiation conversion panel 3 accumulates a latent image due to the energy transmitted through the subject 2.

The radiation conversion panel 3 is irradiated with a stimulable excitation light such as visible light or infrared light from a stimulable excitation light source 4 by a scanning method. This irradiation causes the radiation conversion panel 3 to emit stimulable fluorescent light in proportion to the stored energy.
This light emission is input to the photoelectric converter 6 via the filter 5, and the photoelectric converter 6 converts it into a voltage signal proportional to the light emission intensity and outputs it to the image reading device 7.

The image reading device 7 converts the input voltage signal into digital image data and outputs it to the image processing device 8. As a concrete hardware configuration of the image reading device 7, as shown in FIG. 2, a current / voltage converter 7A for converting the output current of the photoelectric converter 6 into a voltage signal is provided, and the current / voltage converter 7A The output voltage division is A / via the amplifier 7B.
It is input to the D converter 7C. Here, the amplifier 7B may be a logarithmic amplifier. The A / D converter 7C converts the analog voltage into a digital voltage (digital image data) and outputs it to the control circuit 7D. The control circuit 7D adjusts the gains of the current / voltage converter 7A and the amplifier 7B, and the A / D converter 7
The input dynamic range adjustment of C is performed, the reading gain of the radiation image information is comprehensively adjusted, and the image data is transferred to the image processing device 8 at a predetermined timing.

The image processing device 8 stores the digital image data in a memory, controls data input / output for CRT display and film output, sets shooting conditions of a subject, and performs image processing described later. Has become.

Here, the radiation conversion panel 3 can be repeatedly used for photographing, reading and erasing, and the radiation exposure area that can be stored is extremely wide so that the difference in photographing conditions can be corrected and restored by image processing. In addition, communication processing for transmitting digital image data to a host computer or storing digital image data in a film and developing it to secure a reproduced image as a hard copy can be ensured.

As shown in FIG. 1, the image processing device 8 includes an anatomical region determining means 9 and a gradation processing condition determining means 1.
0 and gradation processing means 11 are provided.

As a concrete hardware configuration of the image processing device 8, as shown in FIG.
A CPU (abbreviated as CPU) 21 is provided, and an image monitor 22 as a display unit is connected to the CPU 21 via a display control unit 23 and an image bus VB.

Further, the CPU 21 has a frame memory 24 for storing image processing data etc.
5 and the image bus VB.

Further, a keyboard 26 for inputting identification information (name, birth, date of birth, etc.) of a subject and a display device 27 for displaying this input information are provided, and the keyboard 26 and the display device 27 interface 28. Through the C
It is connected to the PU 21.

A timing control unit 29 for outputting a timing control signal is provided, and the timing control unit 29 outputs the timing control signal to the drive circuit of the X-ray irradiation apparatus 1 via the adapter 30 and also the control circuit 7D. Output to. A magnetic disk 31 serving as a magnetic memory for recording image data is provided, and the image-processed image data is stored in the magnetic disk 31 by a signal from the magnetic disk controller 32. The image data may be recorded by an external optical disk device or a magnetic tape device as shown by the broken line in FIG.

Reference numeral 34 is a memory for storing a control program and the like. Reference numeral 33 is an I / O interface for an external device, and the image processing apparatus 8 can be connected to an external device such as a hard copy.

Here, the CPU 21 causes the anatomical region determining means 9, the gradation processing condition determining means 10, and the gradation processing means 11 to operate.
And make up.

By the way, the technician who operates can directly designate an arbitrary region of interest in the image on the image monitor 22 with a light pen or the like by using the image position designating means such as a touch panel.

In the case of the leg image shown in FIG. 3, the site A (knee), the site B (Achilles tendon), and the site C are shown.
It is not possible to express all of the (toes) in an easy-to-see density / contrast, and by looking at the monitor 22, any one of the areas A, B, and C is designated as an area, and only the specified area is optimized in density / contrast I was able to express it.

Further, the purpose of the leg imaging as shown in FIG. 3 is to sufficiently observe an abnormal portion (fracture, Achilles tendon cutting, etc.), and even if a specific portion is determined in advance, another affected portion may cause a problem. If you have to look at other parts,
Since it is sometimes necessary to shift the density, such processing (expressing optimum density / contrast only in a part of a necessary portion) is important.

In practice, an image as shown in FIG. 3 is displayed on the CRT of the image monitor 22, and a diagnostic target site point which is an arbitrary site of interest is touched on the screen or designated by a mouse or a track bowl. Make sure that the area can be expressed with optimum density / contrast. Further, after the position of the diagnostic target portion is designated, its size / designated shape can be changed.

Further, in the present invention, the output density equivalent value at the designated position is displayed numerically.

In order to make this easy to understand,
It is important to know the output concentration or output signal value of the diagnostic target portion under the current processing conditions. For that reason, a mechanism that can also display the concentration scale is provided.

In the present invention, the output density of the designated portion where the density is considerably light or dark on the contrary is set so that the center position becomes a median value of 0 to 3 such as 1.5 or 1.6. Is selected and the density range is expanded to a wide range close to 0 to 3, and the output density is changed and the gradation is converted.
The specified operation was input as a numerical value (density value).

The density correction method can be performed by designating the upper and lower parts of the overall density. However, as described above, the technician has the know-how for finishing the photograph, that is, when performing image processing. The standard is the concentration at the diagnostic target site
Since the contrast is the contrast and the designation is the direct output density, the designation is easy and the accuracy is improved.

That is, actually, the output density (median value) of 1.5 and the contrast density width of 2 are designated. Then, it is also possible to display the image of the processing result based on the designated value on the CRT of the image monitor 22 and change it again before printing. Also, when the processing conditions are changed again, the direct output density is used for the specification, and the density (median value) is changed from 1.5 to 1.4.
The contrast density width can be changed to 2.4.

In this embodiment, a density scale or the like corresponding to the output density is displayed on the CRT of the monitor 22 so that the density can be designated directly.

That is, the density scale 221 as shown in FIG.
Is displayed on the CRT screen of the same monitor 22 as the image as shown in FIG. 5, and it is possible to compare the current image density with the output density when printing as it is. It is possible to confirm not only the density / contrast but also the density / contrast of the entire image. Therefore, it is possible to roughly estimate the current density and contrast of the region to be designated, which is a great help for designating and inputting the optimum density and contrast of the designated region.

Further, an image 222 of the substantially same region photographed in the past and confirmed to be optimally processed is shown in FIG.
It can be displayed as a sample as shown in.

Further, the designation of the arbitrary specific portion described above is not limited to one.

[0042]

According to the present invention, by designating an arbitrary area on the display screen of an image recorded by the reading means having a wide dynamic range, the current density value of the area is read, the density is changed to the optimum density, and the area is viewed with the optimum contrast. It is equivalent to a so-called zooming function that can improve the operability and prints with the contrast of optimum density, so that regardless of experience, one X-ray exposure can definitely output the required area appropriately. There is.

Further, by reflecting the output density information on the CRT, even if the gradation characteristics of the CRT and the gradation characteristics of the printer do not completely match, it is possible to print with the processing contents decided by the CRT. It will be certain.

Further, by displaying the previously photographed optimally processed image as a sample on the same display screen, it becomes possible to specify and change the density more reliably and easily.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a radiation image processing apparatus including the present invention.

FIG. 2 is a block diagram of the hardware.

FIG. 3 is a diagram illustrating a radiographic image processing image showing a leg portion.

FIG. 4 is a schematic diagram of a density scale shown on a display device.

FIG. 5 is a diagram showing an arrangement example on a CRT screen of an image monitor.

[Explanation of symbols]

1 X-ray irradiation device 3 Radiation conversion panel 6 photoelectric converter 7 Image reading device 8 Image processing device 22 image monitor 221 Concentration scale 222 Optimal image

Claims (7)

[Claims] 1. An image reading unit for reading a radiation image obtained by irradiating a subject with radiation, a storage unit for storing image information by the image reading unit, and information from the image reading unit and / or the storage unit. Image display means for displaying, an image position designating means for arbitrarily designating an in-screen area of the image display means, and the density of the designated area in the screen is changed in association with the designation by the image position designating means. And a radiation image processing apparatus. 2. The radiation image processing apparatus according to claim 1, further comprising image density value display means for displaying an output density equivalent value of the designated area by a numerical value. 3. The radiation image processing apparatus according to claim 1, further comprising a visualized image output unit for printing out, and printing out with an image density corresponding to an output density value of the designated area. 4. A visualized image output means for printing out, and a density designating means for designating an image density of the designated area, wherein the image density of the designated area is printed out at the designated density. The radiation image processing apparatus according to claim 1. 5. The radiation image processing apparatus according to claim 1, wherein the means for changing the output density of the image display means has a function of gradation conversion. 6. The radiation image processing apparatus according to claim 1, wherein the image display unit has a function of displaying a density scale for displaying the output density as a sample. 7. The radiation image processing apparatus according to claim 1, wherein the size / shape designated by the image position designating unit can be changed.