JPH01261787A - Radiograph processor - Google Patents

Abstract

PURPOSE:To obtain a hard copy of an image equal to an image expected from a display image by providing the title device with a density setting means, highlighting an image signal value to be recorded by the set density and displaying the highlighted value on an image display means. CONSTITUTION:A digital image is inputted to a storage device 2 and automatic hierarchical processing is executed by a lookup table 3 based upon a hierarchical processing condition set by a controller 6. When a user specifies density by a density specifying key 93, an image automatically hierarchically processed and highlighted at its specified density part is displayed on a display device 8. When the result of hierarchical processing is not good, the highlighting part is adjusted by a lightness adjusting key 91 so as to be positioned on a portion to be recorded by the specified density by an operation part 9 while observing a picture. Consequently, the portion is recorded by the specified density and a hard copy similar to an image expected from the display image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a radiation image processing bag that performs gradation processing on a digitized radiation image and displays and records the one-gradation processed image.

(Prior Art) Attempts are being made to digitize radiation images used for diagnosis and apply computer technology to process, store, search, and transmit the images. Among these, image processing is known to have the effect of directing the diagnosis, and among the image processing, gradation processing in particular has a simple device and is highly effective. The processed image is displayed on a CRT (cathode ray tube) display or the like or output as a hard copy on photographic film or the like and used for diagnosis.

Even when outputting an image as a bar copy on photographic film, the gradation processing parameters can be diagnosed by the user (for example, a doctor) while displaying the image on a CRT display or the like and checking the gradation processing results. It is preferable to determine the image so that it is suitable for However, when diagnosis is done by hard copy output such as photographic film, CR
Since the characteristics of a display device such as T and the characteristics of a hard copy device such as photographic film are different, the optimal gradation processing image obtained by the user while observing on the display device will be output as a hard copy. There was a problem that it was not optimized.

Regarding this point, the inventor investigated the cause of the difference between the displayed image and the hard copy image, and as a result, the contrast of one image was set in advance so that the displayed image and the hard copy image were equal by adjusting the contrast of the display device etc. However, the brightness of the image (equivalent to the density of a hard copy) may vary depending on external factors such as the brightness of the display device installation location and the condition of the light beam. The absolute value of <<,
We have found that this is the main cause of the difference between the displayed image and the hard copy image. Furthermore, it is important to note that the optimal image density has an optimal density value that corresponds to a specific location (anatomical region) of the subject in a radiographic image, and that doctors, radiographers, etc. who are familiar with radiological images It turned out that he had knowledge of concentration. Therefore, the contrast of the image is determined by the user so that the image is suitable for diagnosis while checking the results on a CRT display or the like.

The density of the image can be determined by specifying the preferred density for a specific region.

(Objects and Structure of the Invention) The present invention has been made with the above-mentioned points in mind, and aims to provide an image that is equivalent to that expected from a display image on a display device such as a CRT, as a hard copy of a photographic film or the like. The purpose is to To achieve this purpose,
A density setting means for setting the density of the recorded image is provided, and the image signal value recorded at the set density is highlighted and displayed on the image display means.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a block diagram showing the configuration of a radiation image processing apparatus according to the present invention.

In the figure, l is a digital image forming device that obtains digitized radiographic images, and this equipment includes a film digitizer that obtains digital images by calculating the density of photographic film as a digital value, and a directly digitized X-ray image forming device. There is a device that can obtain line images. Examples of the former include a laser scanner that scans with a film laser beam, a CCD scanner that scans with a one-dimensional CCD, and a CCD camera that uses a two-dimensional CCD. An example of the latter is to convert an X-ray image into a II tube (Image(nten
A digital fluorography device that amplifies the image with a TV camera and then converts it into a digital image using a TV camera, records an X-ray latent image on a stimulable phosphor, scans it with a laser beam, reads out the image as stimulated luminescence, and then performs photoelectric conversion. There are two methods: one method is to scan a dot-like or linear radiation detector to directly obtain an electrical signal and digitize it. As the digital image forming apparatus 1.

Various other digital radiation devices such as computerized tomography devices, nuclear medicine devices, nuclear magnetic resonance imaging devices, ultrasound imaging devices, etc. are also used.

2 is a storage device that stores digital images, and 3 is a lookup table (L) that performs gradation processing of digital images.
OT), 4 is a storage device that stores the gradation-processed digital image, and 5 is a hard copy device that records the gradation-processed image. As the hard copy device 5, for example, a device that photographs a CRT screen onto a photographic film, a laser printer or a thermal printer that scans and exposes the photographic film with modulated laser light is used. 6 is Luukua
This is a control device that sets gradation processing conditions for the gradation table 3. For example, a microcomputer is used as the control device 6. Is control bag ε6 a memory device? After receiving the image signal from I2, the properties of one image, such as the distribution of image signal values (
gradation processing conditions are set based on a predetermined program according to the histogram) and the type and part of the subject.

FIG. 2 shows a processing function showing an example of the gradation processing conditions.

When a digital image signal shown on the horizontal axis is input to the lookup table 3, a corresponding gradation-processed signal shown on the vertical axis is output from the lookup table 3.

7 highlights the image signal value set by the control device 6 in the gradation-processed image (emphasizing a part of the image by making it particularly brighter or darker than other parts of the image) This is a lookup table that is output to the display device 8. As the display device, a CRT display or a liquid crystal display is used.

9 is an operation unit for changing gradation processing conditions, and this operation unit 9 includes a brightness adjustment key 91 for adjusting the brightness of the entire image, a contrast adjustment key 92 for adjusting the contrast of one image, and a hard copy. It has a density designation key 93 for designating the optical density of the recorded image recorded by the device 5.

Brightness adjustment key 91? : When operated, the gradation processing function f shown in FIG. 2 moves in the horizontal axis direction as a whole, the range of the input image signal changes, and the brightness of the entire image changes. Further, when the contrast adjustment key 92 is operated, the slope of the gradation processing function f changes, and the contrast of the image is adjusted.

The density specification key 93 specifies the optical density of the recorded image using a numerical value or a part of the subject. In the latter case, for example, when "chest" is selected, a preset optical density (for example, 1.3) is set.The memory in the control device 6 stores the signal value of the 1-gradation processed signal and its value. Data indicating the correspondence between the optical density and the optical density when outputted by the hard copy device 225 is stored in advance, and when the optical density is specified using the key 93.

The control device 6 controls the output characteristics of the look-up table 7 so that the image signal value corresponding to the optical density is highlighted. That is, as shown in FIG.
The image signal value X corresponding to the density specified by is converted into a white signal and output, and the display device 8 displays that portion in white. This highlighting area varies depending on the part of the subject, but for example, when the brightness of the entire image changes, which appears as a closed loop like contour lines on a map, the highlighting area moves.
When the highlighting portion is set to a desired area to be recorded at the specified density, that area is outputted from the hard copy device 5 at the specified density.

Furthermore, the control device 6 matches the signal value that remains unchanged during contrast adjustment with the signal value that is highlighted. For example, when the gradation processing function is changed as shown by the broken line f' in Figure 2, the output value of the input signal x0 remains unchanged, and this output value is the highlighted signal value X (see Figure 3). This is done so that it has the same value as . The reason for this is that even if the contrast is changed after the highlighting process is decided, the highlighted signal value remains unchanged, so there is no need to change the highlighting process again. There is a strong possibility that they are the same since the concentrations correspond to important parts of the body.

By the way, when the gradation is in small increments, if only the specified signal value is highlighted, the highlighted part will be too small and difficult to see. In this case, it is best to highlight with a certain width centered around the specified signal value.

Next, the operation will be explained using the flowchart shown in FIG.

First, a digital image from the digital image forming apparatus 1 is loaded into the storage device 2 (F-1), and automatic gradation processing is performed by the lookup table 3 based on the gradation processing conditions set by the control device 6 (F-1). -2), Meanwhile, the user specifies the C degree using the concentration specification key 93 (F-3)
. The display device 8 displays an automatically gradated and partially highlighted image. The user checks this displayed image (F-4) and determines whether the gradation processing is appropriate (F-4).
5) If the image is good, record the image using the hard copy device Fa5 (F-7). If the result of gradation processing is not good, change the processing using the operation unit 9 while looking at the screen (F-7).
6). For example, use the brightness adjustment key 9 to adjust the brightness so that it is located in the highlighted area or in the area where you want to record with the specified density. With such adjustment, the area will be recorded at the specified density, and a hard copy similar to the image expected from the displayed image will be obtained. Also, regarding contrast -
Use the adjustment key 92 to adjust while looking at the screen so that the optimum contrast can be obtained. During this contrast adjustment, highlighting may be turned off so as not to interfere with the adjustment.

Further, contrast adjustment may be performed by automatic gradation processing.

In the embodiment L, the density of the recorded image can be arbitrarily set using the density specification key 93, but this density depends on the type of radiation image being processed, the imaging method, the part of the subject, the case, etc. It may be set in advance by one image.

Also, in order to correct or match the characteristics of the display device 8 and the hard copy device 5, a lookup table 7 is used.
Good results are often obtained by placing a correction device (this can be implemented using a look-up table) between the display device 2t8 and the storage device 4 and the hard copy device 5. The lookup table 7 placed between the lookup table 7 and the display device 8 is also used as the lookup table 7 for highlighting, so that correction and highlighting can be performed at the same time.

Depending on the type of image display device or hard copy device, the image is displayed or recorded pixel by pixel sequentially, so that the second image storage device 4 can be omitted by processing each pixel each time. In this case, for example, the lookup table for gradation processing and the lookup table for highlighting may be used together, and by performing correction and highlighting at the same time, lookup table 3 shown in FIG. ! The control device 6 can also perform not only gradation processing but also other image processing, such as image distortion correction and frequency characteristic processing, at the same time. It may be something that can be done. Furthermore, if the display device 8 is capable of color display and highlighting is performed by changing the color of the image, it will be easier to see and use.

In the above description, the image processing apparatus that performs automatic gradation processing has been described, but it goes without saying that the present invention can also be applied to an apparatus that does not perform automatic gradation processing.

(Effects of Ill) As described above, according to the present invention, a density setting means for setting the density of a recorded image is provided, and the image signal value recorded at the set density is highlighted to display the image. Since the density of the recorded image can be determined while viewing the displayed image by displaying it on the means, it is possible to obtain a hard copy of an image equivalent to that expected from the displayed image.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the radiation image processing device according to the present invention, FIG. 2 is a diagram showing the gradation processing function of the device in FIG. 1, and FIG. 3 is a diagram showing the device in FIG. 1. FIG. 4 is a flowchart explaining the operation of the embodiment. 3.7... Lookup table, 91... Brightness adjustment key, 92... Contrast adjustment key, 93...
Density specification key

Claims (3)

[Claims] (1) In a radiographic image processing apparatus capable of performing gradation processing on a digitized radiographic image, displaying the gradation-processed image on an image display means, and recording it with an image recording means, the image recording means A density setting means for setting the density of a recorded image to be written, and a highlighting means for highlighting an image signal value recorded at the density set by the density setting means and displaying it on the image display means. A radiation image processing device characterized by: (2) The radiation image processing apparatus according to claim 1, wherein the density set by the density setting means is a density that remains unchanged in the image when contrast conversion is performed by gradation processing. (3) The radiation image processing apparatus according to claim 1, wherein the image signal value highlighted and displayed by the highlighting means has a constant width centered on the designated image signal value.