JPH06261252A - Radioactive ray image processor - Google Patents

Abstract

PURPOSE:To improve operability, to finish the exposure of radiation by one time by performing an output print by the contrast of optimum density, to unnecessitate considerable amount of experience and trial and errors and to unnecessitate complicated operations. CONSTITUTION:An image reader 7 is provided with a current/voltage converter 7A converting the output current of a photoelectric converter 6 into a voltage signal and the output partial voltage of a converter 7A is inputted into an A/D converter 7C via an amplifier 7B. The converter 7C converts analog voltage into digital voltage and outputs it to a control circuit 7D. The circuit 7D performs the gain ajustment of both the converter 7A and the amplifier 7B, performs the input dynamic range adjustment of the converter 7C, performs the comprehensive adjustment of the read gain of radiation image information and transfers image data to an image processor 8 at a prescribed timing. The device 8 makes digital image data be stored in a memory 31, performs a data input/output control for the CRT display and the film output of an image monitor 22 and performs the setting of the photographing conditions of an object and an image processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 about 0 to 3. 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 Japanese Patent Laid-Open No. 2-278471, a user (operator) uses a display section and a keyboard (input means) to perform image processing parameters for image signals accumulated by photographing, such as gradation processing and frequency processing. However, the process of determining the parameters to be specifically set is not shown, and in the description that follows, the user will be able to confirm the quality of the visualized image. It is indicated that the examination should be carried out including doctors and the parameters should be set 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 parameters.
It is by no means an indication that development is still under way.

[0008]

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.

[0009]

This object is achieved by any of the following technical means a, b and c.

(A) Image reading means for irradiating a subject with radiation to photoelectrically read a visible image formed on the phosphor,
Storage means for storing image information by the image reading means,
An image display means for displaying information from the image reading means and / or the storage means, an image position designating means for arbitrarily designating an in-screen area of the image display means, and the screen in cooperation with the image position designating means. The image density value display means for numerically displaying the output density equivalent value of the designated area of the display image, and the means for changing the output density of the image display means. A radiation image processing device, wherein the visualized image output means prints out with an image density corresponding to the above, and the image density of the specified area is printed out with a specified density.

(B) In addition to the item (a), the radiation image processing apparatus is characterized in that the means for changing the output density of the image display means also has the function of gradation conversion.

(C) A radiation image processing apparatus characterized in that, in addition to the item (a), the image display means has a function of also displaying a density scale for sample-displaying the output density.

[0013]

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.

The image reading means outputs a 12-bit digital data having a wide dynamic range of 0 to 4095, while converting it to a density of 0 to 3 to improve the recognition of the density. Is.

This produces an effect of making it easy to recognize the deviation between the average density or the median value and the median value of the output print density which is easy to see.

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

[0018]

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 composed of an X-ray tube or 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 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 differences 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 10.
And a 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 means is connected to the CPU 21 via a display controller 23 and an image bus VB.

A frame memory 24 for storing image processing data and the like is connected to the CPU 21 via a frame memory controller 25 and an 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. It is connected to the CPU 21 via.

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 image data subjected to image processing is stored in the magnetic disk 31 by a signal from the magnetic disk control unit 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 denotes an I / O interface for an external device so that the image processing device 8 can be connected to an external device such as a hard copy.

Here, the CPU 21 constitutes an anatomical region determining means 9, a gradation processing condition determining means 10 and a gradation processing means 11.

By the way, the technician who operates can directly specify an arbitrary region of interest in the image on the image monitor 22 with a light pen or the like by using an image position specifying 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 has the optimum density /
I made it possible to express with contrast.

Further, the purpose of photographing the leg as shown in FIG. 3 is to sufficiently observe the abnormal part (fracture, Achilles tendon amputation, etc.). 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 selected so that the center position becomes the median value of 0 to 3 such as 1.5 or 1.6. The output density is changed and the gradation is converted so that the range is expanded to a wide range close to 0 to 3, and the designated operation is 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, but as described above, the technician has the know-how for finishing the photograph, that is, the 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, as shown in FIG. 3, the output density (median) 1.5 and the contrast density width 2 are designated. Then, it is 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 changing the processing condition again, the direct output density is used to specify it, and the density (median) is
Made it possible to change 1.5 from 1.4 and contrast density width 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. 4 is displayed on the CRT screen of the monitor 22 which is the same as the image as shown in FIG. 5, and the current image density can be compared with the output density when printed as it is. Yes, by doing this, not only the density / contrast of the diagnostic target site,
It is possible to confirm the state of 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, it is possible to display, as a sample, an image 222 of the almost same region photographed in the past and confirmed to be optimally processed, as shown in FIG. Further, the designation of the arbitrary specific portion described above is not limited to one.

[0043]

According to the present invention, by designating an arbitrary area on the display screen of an image recorded by a 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 the optimum density, so that regardless of experience, a single X-ray exposure will 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 content determined by the CRT. It will be certain.

Further, by displaying the optimally processed image photographed in the past 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 showing a radiographic image processed 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 Density scale 222 Optimum image

Claims (3)

[Claims] 1. An image reading means for photoelectrically reading a visible image formed on a phosphor by irradiating a subject with radiation, a storage means for storing image information by the image reading means, and the image reading means and / or Alternatively, an image display means for displaying information from the storage means, an image position designation means for arbitrarily designating a screen area of the image display means, and the designation of a display image on the screen in cooperation with the image position designation means. The image density value display means for numerically displaying the output density equivalent value of the area and the means for changing the output density of the image display means are provided, and the image density value corresponding to the output density value of the designated area is displayed. A radiation image processing apparatus, wherein the visualized image output means for printing out prints out the image density of the specified area at a specified density. 2. A radiation image processing apparatus according to claim 1, wherein the means for changing the output density of the image display means also has a function of gradation conversion. 3. A radiation image processing apparatus according to claim 1, wherein the image display means has a function of displaying a density scale for displaying the output density as a sample.