JP4054785B2 - Radiation image processing apparatus and radiation image processing method - Google Patents

Description

  The present invention relates to a radiographic image processing apparatus and a radiographic image processing method for processing a digital image obtained by radiography.

  In recent years, radiation such as X-rays is irradiated on a subject, a radiographic image as a transmission image thereof is directly captured using a solid-state imaging device, and an image signal corresponding to the captured radiographic image is displayed on a CRT (Cathode Ray Tube). A radiographic imaging system that displays as a visible image by an apparatus or the like, or digitizes an image signal corresponding to a captured radiographic image, performs image processing in the state of digital data, and then prints it out Has been developed (see Patent Document 1).

In the above-described radiographic imaging system, the part to be imaged differs depending on the imaging purpose, and in the image processing performed when the radiographic image is visualized, the optimum density and gradation differ for each image of the part to be processed. It is necessary to perform different image processing for each image of each part.
Japanese Patent No. 3413085

  Recently, computer networks are gradually being developed in medical facilities. In addition to the above radiographic imaging system, a radiographic imaging device (CR) and an image intensifier using a stimulable phosphor sheet are also available. Radiation image information captured by different radiation image capturing devices such as the used radiation image capturing device (DR) is processed by the same image processing device, and the processed radiation image information is processed by a CRT display device, a film imager device or a dry printer. It may be used in such a way that it is output to a different output device such as a device.

  In the case described above, in order for the image processing performed in the image processing apparatus to correspond to each photographing apparatus and output apparatus, an operator who operates the image processing apparatus must perform setting operations for a plurality of procedures. In other words, it was very complicated for the operator.

  In addition, when the chest is imaged, the region of interest is different from the case of the lung field to the case of the bone. Therefore, depending on whether the actual region of interest is the lung field or the bone, The operator himself / herself operates an input device such as a mouse or a touch panel so as to perform image processing with gradation, and the image processing apparatus needs to be set so as to perform image processing corresponding to the region of interest in the radiation image. For those, these operations were also time-consuming.

  The present invention has been made to solve the above-described problems, and a radiation image processing apparatus capable of automatically performing image processing on a radiation digital image without bothering an operator, and An object is to provide a radiation image processing method.

In order to achieve the above object, a radiographic image processing apparatus according to the present invention includes a discriminating unit that discriminates the type of imaging region indicated by radiographic digital image data;
A memory table that stores information on the position of the photosensor that controls the exposure intensity of the radiation according to the intensity of the detected radiation, corresponding to the type of imaging region;
Information on the position of the photosensor is read from the memory table on the basis of information on the type of the imaging region determined by the determining means, and information on the image area corresponding to the position of the read photosensor in the radiation digital image data is obtained. Photo sensor area designation means for output;
For use in image processing based on the pixel values in the image area based on the radiation digital image data and information data on the image area corresponding to the position of the photosensor output from the photosensor area designating means. A feature amount calculating means for calculating a feature amount;
Image processing means for performing density conversion processing on the radiation digital image data according to a density conversion curve having a density conversion characteristic in which the feature quantity calculated by the feature quantity calculation means becomes a predetermined density value;
It is characterized by having.
Furthermore, in a radiation image processing method for processing radiation digital image data obtained by radiation imaging,
A determination step of determining a type of an imaging region indicated by the radiation digital image data;
The photo sensor area specifying means includes a memory table that stores information on the position of the photo sensor that controls the exposure intensity of the radiation according to the intensity of the detected radiation, corresponding to the type of imaging region,
The photosensor area designating unit reads out information related to the position of the photosensor from the memory table based on information related to the type of imaging region determined in the determination step, and the position of the read photosensor in the radiation digital image data A photosensor area designating process for outputting information of an image area corresponding to
Based on the radiation digital image data output in the image data forming step and the information data on the image region corresponding to the position of the photosensor output in the photosensor region specifying step, the feature amount calculating means A feature amount calculating step for calculating a feature amount for use in image processing based on a pixel value in the image region;
An image for the image processing means to perform density conversion processing on the radiation digital image data according to a density conversion curve having a density conversion characteristic in which the feature quantity calculated in the feature quantity calculation step becomes a predetermined density value. Processing steps ;
It is characterized by having.

(Function)
With the above-described configuration, it is possible to automatically perform optimum image processing on image data without bothering the operator.

  As described above, according to the present invention, optimal image processing can be automatically performed on a radiation digital image without bothering the operator.

  Hereinafter, the present invention will be described in detail based on a radiation digital image processing system as an embodiment of the present invention.

  FIG. 1 is a diagram showing a schematic configuration of a radiation digital image processing system as an embodiment of the present invention.

  In FIG. 1, reference numeral 10 denotes an image data forming unit that outputs radiation digital image data to an image recording unit 11 at a subsequent stage. The image data forming unit irradiates a subject with radiation such as X-rays, and directly captures a radiation image as a transmission image thereof. A radiographic imaging device that captures an image using an element and outputs radiation digital image data corresponding to the captured radiographic image. In addition to the radiographic imaging device, the image data forming unit 10 is a radiographic image reading device that reads a radiographic image accumulated and recorded on a photostimulable phosphor sheet. A radiation image is received by a fluorescent screen, and the received light image of the fluorescent screen is converted into radiation digital image data by a solid-state image sensor, or a radiation digital supplied from a radiation image capturing device connected to a computer network There is an input interface for inputting image data. That is, the image data forming unit 10 itself does not have to be a radiographic image capturing device. For example, radiographic image data indicating a radiographic image captured by a radiographic image capturing device installed in a remote hospital or the like is stored on the Internet or the like. It may be configured to be input to the digital radiographic image processing system via the computer network.

  Reference numeral 11 denotes an image data recording unit for recording the radiation digital image data output from the image data forming unit 10, and is composed of, for example, a semiconductor memory or a hard disk drive device capable of writing data at high speed.

  12 sets the type of the device outputting the radiation digital image data in the image data forming unit 10, and sets the information data indicating the set type of the device to the photosensor area specifying unit 15 and the image processing unit 17 in the subsequent stage. It is a setting part which outputs to. The setting unit 12 is operated by the operator himself / herself by operating buttons and dials provided on the console, or by operating a keyboard and mouse that are input devices of the computer. Is configured to directly manually set the type of device that outputs radiation digital image data, or for example, DICOM, which is a digital image communication standard in medicine, forms radiation digital image data in the radiation digital image data. Since the information about the device is added, information about the device on which the radiation digital image data is formed is added to the radiation digital image data output from the image data forming unit 10 or the image data recording unit 11. In this case, radiation digital image data is output according to the added information. It determines the type of location, and is configured to automatically set.

  Reference numeral 13 denotes a determination unit that determines the type of the part indicated by the radiation digital image data output from the image data forming unit 10 and outputs information data indicating the determined type of the part to the subsequent image processing unit 17. . The discriminating unit 13 is operated by the operator himself / herself by operating buttons and dials provided on the console, or by operating a keyboard and a mouse which are input devices of the computer. Is configured to directly and manually set the type of the part indicated by the radiation digital image data. For example, in DICOM which is a digital image communication standard in medical care, the kind of part indicated by the radiation digital image data is included in the radiation digital image data. Therefore, when information on the type of the part indicated by the radiation digital image data is added to the radiation digital image data output from the image data forming unit 10, the added information According to the information, the type of the part indicated by the radiation digital image data is discriminated and set automatically. It is configured.

15 has a memory table that stores information about the location of the photo sensor to the radiation ray image capturing device corresponding to the kind of radiation ray image photographing apparatus is set in the setting unit 12, the setting unit 12 Based on the information on the type of the device that outputs the radiation digital image data set in step 1, information on the arrangement position of the photosensor on the radiation digital image is read from the memory table, and the position of the photosensor on the radiation digital image Is a photosensor area designating unit that outputs information about the image area corresponding to the feature amount calculating unit 16 in the subsequent stage.

  15 has a memory table that stores information relating to the arrangement position of the photosensor of the radiation digital image capturing apparatus corresponding to the type of the radiation digital image capturing apparatus set in the setting section 12, and the setting section 12 Based on the information on the type of the device that outputs the radiation digital image data set in step 1, information on the image area corresponding to the position of the photosensor on the radiation digital image is read from the memory table, and the read information Is a photosensor area designating unit that outputs the output to the feature quantity calculating unit 16 in the subsequent stage.

  The photosensor is a sensor for detecting the intensity of radiation to be irradiated at the time of radiography. In the radiographic imaging apparatus, the photosensor is used so that the exposure at the time of radiography is in a desired state. The exposure intensity of the radiation is controlled according to the intensity of the radiation detected by. For example, when the radiographic imaging device is for chest imaging, a photosensor is arranged at a position where the chest of the patient as a subject hits, so that the operator can guide the patient's standing position. By visually displaying the position and shape of the photosensor arranged on the light receiving plate, the operator adjusts the patient's standing position to the position where the patient's chest is in contact with the display, The exposure intensity of the radiation can be controlled so that the exposure at the time of radiography is appropriate in the region centered on. In this case, the image area corresponding to the position of the photosensor on the radiation digital image coincides with the display.

  Further, the information about the image region corresponding to the position of the photosensor on the radiation digital image output from the photosensor region designating unit 15 to the feature amount calculating unit 16 is the image region directly cut out from the radiation digital image. Or information data indicating coordinates indicating the position of the image region on the radiation digital image.

Further, the photosensor region designation unit 15 includes a memory table corresponding to the type of imaging area to be determined in the discrimination unit 13 stores information about the location of the photo sensor of the radiation ray image capturing device, Based on the information related to the type of imaging region determined by the determination unit 13 , information related to the position of the photosensor on the radiation digital image is read from the memory table, and an image corresponding to the position of the photosensor on the radiation digital image. Information regarding the region may be output to the feature amount calculation unit 16 in the subsequent stage.

16 is based on radiation digital image data output from the image recording unit 11 and information data on an image region corresponding to the position of the photosensor on the radiation digital image output from the photosensor region designating unit 15. The feature amount calculation unit that calculates information about the feature amount such as the maximum value, the minimum value, the average value, the median value, and the mode value of the pixel values in the image region. It is output to the processing unit 17.

  16 is a photosensor on the radiation digital image indicated by the radiation digital image data output from the image recording unit 11 and the radiation digital image data output from the image recording unit 11 output from the photosensor area designating unit 15. Based on the information data on the image area corresponding to the position of the image area, the feature amount calculation for calculating information on the feature quantity such as the maximum value, the minimum value, the average value, the median value, the mode value, etc. Information data on the calculated feature value is output to the image processing unit 17 at the subsequent stage.

  17 shows information indicating the type of radiation imaging apparatus output from the setting unit 12, information regarding the imaging region output from the determination unit 13, and the type of output device output from the output device selection unit 14. The image area corresponding to the position of the photosensor has an optimum density and / or gradation based on the information shown and the information on the feature quantity of the radiation digital image output from the feature quantity calculation unit 16. It is an image processing unit for performing image processing on the radiation digital image data recorded in the image recording unit 11.

  An image output unit 18 is supplied from the image processing unit 17 to an output device such as a CRT display device, a film imager device, a dry printer device, or an output device connected to a computer network, as described above. An interface for outputting a digital radiation image. That is, the image output unit 18 itself does not need to be an output device. For example, an output device installed in a remote hospital or the like can be connected to the digital radiographic image processing system via a computer network such as the Internet. It may be configured to be input.

  Here, as an example of taking a picture of a patient's chest using a radiographic digital imaging device in which a photosensor is arranged at the position shown in FIG. 2, and printing the radiographic image taken on a film and outputting it, The operation of the radiation digital image processing system will be described in detail.

  In FIG. 2, reference numeral 20 denotes a breastplate of a radiation digital image capturing apparatus that is in contact with the chest of a patient as a subject. Is located in the area.

  First, the radiation digital image data corresponding to the radiation image of the patient's chest output from the image data forming unit 10 having the radiation digital image capturing apparatus in which the photosensor is arranged at the position shown in FIG. 11 and recorded in a semiconductor memory, a hard disk drive, or the like.

  On the other hand, in the case where the patient's chest is imaged by the above-described type of radiation digital image capturing device, the photosensor area designating unit 15 is a device that outputs the radiation digital image data set in the setting unit 12. Information on the image area corresponding to the position of the photo sensor in the radiation digital image capturing apparatus used for imaging from the memory table storing the information on the arrangement position of the photo sensor of each radiation digital image capturing apparatus according to the information on the type (That is, information indicating the image areas 21 and 23 in FIG. 2) is read and output to the feature amount calculation unit 16.

  The feature amount calculation unit 16 cuts out an image area corresponding to the position of the photosensor from the radiation digital image data supplied from the image data recording unit 11 and adds all the pixel values in the cut out image area. Then, the total addition value is calculated, and the average value A is calculated by dividing the calculated total addition value by the number of pixels in the image area corresponding to the position of the photosensor, and is output to the image processing unit 17.

  By the way, in the case of this operation example, the type of the radiation digital imaging apparatus used for imaging is set in the setting unit 12, the imaging part is determined as the chest, and the output device selection unit 14 further outputs the output device. As the film imager device is selected, the average value A supplied as information on the feature amount from the feature amount calculation unit 16 in the image processing unit 17 is optimal on the film finally output from the film imager device. Density conversion processing is performed based on a density conversion curve having density conversion characteristics such that a correct density value D is obtained.

  The image processing unit 17 includes a look-up table (hereinafter simply abbreviated as LUT) that stores a plurality of types of data indicating density conversion curves serving as a reference for density conversion processing for each imaging region. Data relating to the density conversion curve corresponding to the imaging region determined in step S3 is read from the LUT. That is, in the case of this operation example, data indicating a density conversion curve for “chest” having density conversion characteristics as indicated by a thick line in FIG. 3 is automatically read from the LUT.

  Then, the image processing unit 17 translates the density conversion curve indicated by the data read from the LUT so that the average value A calculated by the feature amount calculation unit 16 becomes the density value D, and the actual density It is corrected to a density conversion curve (density conversion curve having density conversion characteristics as shown by a thin line in FIG. 3) used for the conversion process.

  Then, the image processing unit 17 performs density conversion processing on the digital radiographic image indicated by the digital radiographic image data obtained by imaging the patient's chest output from the image data recording unit 11 according to the corrected density conversion curve. Then, the digital radiation image data subjected to the density conversion process is supplied to the image output device 18.

  The image output device 18 prints a digital radiographic image having an optimum density on the film by printing the digital radiographic image on the film with a laser intensity corresponding to the pixel value indicated by the digital radiographic image data supplied from the image processing unit 17. Can be formed.

  In the above operation example, the case where the imaging region is “chest” has been described as an example. However, for example, when the imaging region is “abdomen”, the positions of the photosensors 21, 22, and 23 in FIG. The feature amount of the image is calculated from all of the corresponding image regions, and density conversion processing may be performed based on the calculated feature amount. When the imaging region is “limb”, the photo indicated by 22 in FIG. The feature amount of the image may be calculated only from the image region corresponding to the position of the sensor, and density conversion processing may be performed based on the calculated feature amount. Furthermore, in this case, it is not necessary to use a radiographic imaging apparatus in which photosensors are arranged at all positions 21, 22, and 23 in FIG. 2, and only photosensors at positions 22 shown in FIG. Radiation digital imaging can be performed by the radiographic image capturing apparatus in which is arranged.

1 is a block diagram showing a schematic configuration of a radiation digital image processing system as an embodiment of the present invention. It is a figure for demonstrating the installation position of the photosensor in the radiographic imaging apparatus of the radiographic digital image processing system shown in FIG. It is a figure for demonstrating the density | concentration conversion characteristic which the data memorize | stored in the look-up table (LUT) in the image processing part of the radiation digital image processing system shown in FIG. 1 shows.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image data formation part 11 Image data recording part 12 Setting part 13 Discriminating part 14 Output device selection part 15 Photosensor area | region designation | designated part 16 Feature-value calculation part 17 Image processing part 18 Image output part

Claims (5)

A discriminating means for discriminating the type of imaging region indicated by the radiation digital image data;
A memory table that stores information on the position of the photosensor that controls the exposure intensity of the radiation according to the intensity of the detected radiation, corresponding to the type of imaging region;
Information on the position of the photosensor is read from the memory table on the basis of information on the type of the imaging region determined by the determining means, and information on the image area corresponding to the position of the read photosensor in the radiation digital image data is obtained. Photo sensor area designation means for output;
For use in image processing based on the pixel values in the image area based on the radiation digital image data and information data on the image area corresponding to the position of the photosensor output from the photosensor area designating means. A feature amount calculating means for calculating a feature amount ;
Image processing means for performing density conversion processing on the radiation digital image data according to a density conversion curve having a density conversion characteristic in which the feature quantity calculated by the feature quantity calculation means becomes a predetermined density value;
A radiation image processing apparatus comprising: Comprising image data forming means for outputting the radiation digital image data;
The said determination means is comprised so that the said imaging | photography site | part may be discriminate | determined according to the information regarding the said imaging | photography site | part added to the said radiation digital image data output from the said image data formation means. The radiographic image processing apparatus according to 1. The image processing unit includes a look-up table that stores data indicating a density conversion curve in association with the imaging region, and the image processing unit determines from the lookup table according to the imaging region determined by the determination unit. The radiation image according to claim 2, wherein gradation conversion processing is performed on the radiation digital image data using data indicating a density conversion curve and using the read data indicating the density conversion curve. Processing equipment. The radiological image processing apparatus according to claim 1, wherein the feature amount is one of a maximum value, a minimum value, an average value, a median value, and a mode value. In a radiation image processing method for processing radiation digital image data obtained by radiation imaging,
A determination step of determining a type of an imaging region indicated by the radiation digital image data;
The photo sensor area specifying means includes a memory table that stores information on the position of the photo sensor that controls the exposure intensity of the radiation according to the intensity of the detected radiation, corresponding to the type of imaging region,
The photosensor area designating unit reads out information related to the position of the photosensor from the memory table based on information related to the type of imaging region determined in the determination step, and the position of the read photosensor in the radiation digital image data A photosensor area designating process for outputting information of an image area corresponding to
Based on the radiation digital image data output in the image data forming step and the information data on the image region corresponding to the position of the photosensor output in the photosensor region specifying step, the feature amount calculating means A feature amount calculating step for calculating a feature amount for use in image processing based on a pixel value in the image region;
An image for the image processing means to perform density conversion processing on the radiation digital image data according to a density conversion curve having a density conversion characteristic in which the feature quantity calculated in the feature quantity calculation step becomes a predetermined density value. Processing steps;
A radiation image processing method comprising:

Images