JP2000101843A - Radiation image processing system - Google Patents

Abstract

(57) [Problem] To provide a radiation digital image processing system capable of automatically performing optimal image processing on a radiation digital image without bothering an operator. SOLUTION: An arrangement of a photosensor for inputting radiation digital image data obtained by digitizing an image obtained by radiation imaging and detecting intensity at the time of radiation imaging on the radiation digital image indicated by the input radiation digital image data is provided. Designate an image area corresponding to the position, and according to the feature amount in the image area corresponding to the arrangement position of the photosensor on the designated radiation digital image,
With respect to the input radiation digital image data, the dynamic range of the radiation digital image indicated by the radiation digital image data is controlled, and then visualized and output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation digital image processing system for processing a radiation digital image, and more particularly to a radiation digital image processing system for controlling a dynamic range of a radiation digital image.

[0002]

2. Description of the Related Art In recent years, radiation such as X-rays has been irradiated onto a subject, a radiation image as a transmission image thereof has been directly captured using a solid-state imaging device, and an image signal corresponding to the captured radiation image has been output to a CRT (CRT). It is displayed as a visible image on a display device such as a Cathode Ray Tube or digitized image signal corresponding to the captured radiation image, and is subjected to image processing in the state of digital data and then printed out. Various radiographic imaging systems have been developed.

In the above-described radiographic image capturing system, the region to be imaged is different depending on the purpose of the image capturing, and in the image processing performed when visualizing the radiographic image, the optimum density and gradation are different for each region to be processed. Therefore, it is necessary to perform different image processing for each image of each part.

[0004] For example, a chest radiographic image obtained by imaging the chest is composed of an image area of a lung field which easily transmits radiation and has a high density value, and an image area of a mediastinal part which is very hard to transmit radiation and has a low density value. Since the dynamic range of the density value indicated by the pixels constituting the radiographic image becomes very wide, both the lung field and the mediastinum in the chest radiographic image are displayed on the same image. At the same time, it has been considered difficult to obtain images that can be observed well.

Therefore, as a method for solving the above-mentioned problem, conventionally, a "self-compensating digital filter" (refer to "Journal of the Japan Society of Radiological Technology, Vol. 45, No. 8, August 1030, 1989, Anan Mitsuhiro et al.") Is used. A process has been performed in which a radiographic image is corrected using a filter so that a doctor can easily view an image region (region of interest) that he or she wants to observe.

The self-compensating digital filter described above means that the pixel value after compensation (after processing) is S _D , the pixel value of the original (input) is S _org , and M pixels × M pixels on the original image (input image). Move the size mask,
When the average pixel value obtained by calculating the average of the pixel values existing in the mask at each moving location is S _US and the function curve as shown in FIG. 10 is a function f (x),

[0007]

[Outside 1] This is a filter represented by the following equations (1) and (2).

Here, a function f as shown in FIG.
The characteristics of (S _US ) will be described. "BA" in the figure
Assuming that “SE” is a density reference value and “SLOPE” is a compression coefficient, the function f (S _US ) is “0” in the density range of the pixel value of “S _US > BASE”, and “0 ≦ S _US ≦ BAS
In the density region of the pixel value of “E”, the function f (S _US ) ends with the density reference value “BASE” as the end point, and the compression coefficient “SLOPE”
And monotonically decreases. Accordingly, by processing the pixel value S _org of the original image by the “self-compensating digital filter” shown in the above equation (1), “in the region where the average density value (average pixel value S _US ) of the image is low,
The density value is raised, and the dynamic range of the low density value area is compressed, but the contrast of the fine structure in each area is maintained, and the low density value area as a whole is darkened while the contrast of the fine structure is maintained. Is converted to an image ".

[0009]

However, in the method of correcting a radiographic image using the “self-compensating digital filter” as described above, the density reference value “BAS
As the values of “E” and the values of the compression coefficient “SLOPE” are predetermined values that have been conventionally empirically obtained, the physique of the patient to be imaged or the subject, such as the physique or radiation dose of radiation, etc. Due to the difference, the effect of the dynamic range compression is different, and it is very difficult and time-consuming to perform the optimal dynamic range compression for each of the imaging region and the physique or radiation irradiation dose of the patient who is the subject. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is capable of automatically performing optimal image processing on a radiation digital image without bothering an operator. It is an object to provide a digital image processing system.

[0011]

In order to achieve the above object, a radiation digital image processing system according to the present invention comprises:
Input means for inputting radiation digital image data obtained by digitizing an image obtained by radiation imaging, and a photo for detecting the intensity at the time of radiation imaging on the radiation digital image indicated by the radiation digital image data input by the input means A photosensor area designating unit that designates an image area corresponding to the sensor arrangement position; and a feature amount in an image area corresponding to the photosensor arrangement position on the radiation digital image designated by the photosensor area designation unit. A feature amount generating unit;
Image processing for controlling a dynamic range of a radiation digital image indicated by the radiation digital image data with respect to the radiation digital image data input by the input means in accordance with the information related to the characteristic amount generated by the characteristic amount generation means. The image processing apparatus includes: an image processing unit that performs the image processing; and an image output unit that visualizes and outputs a radiation digital image corresponding to the radiation digital image data on which the image processing has been performed by the image processing unit.

(Operation) With the above-described configuration, optimal image processing can be automatically performed on a radiation digital image without bothering the operator.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 for forming radiation digital image data, which irradiates a subject with radiation such as X-rays, and directly transmits a radiation image which is transmitted by using a solid-state image sensor. This is a radiation image capturing apparatus that captures images and outputs radiation digital image data corresponding to the captured radiation images. The image data forming unit 10 includes, in addition to the radiation image capturing apparatus, a radiation image reading apparatus that reads a radiation image accumulated and recorded on a stimulable phosphor sheet, irradiates a subject with radiation, and uses the transmitted image thereof. A radiation image receiving device that receives a certain radiation image with a fluorescent plate and converts the received light image of the phosphor into radiation digital image data by a solid-state imaging device, or radiation supplied from a radiation image capturing device connected to a computer network There is an input interface for inputting digital image data. That is, the image data forming unit 10 itself does not need to be a radiation image capturing apparatus. For example, radiation image data indicating a radiation image captured by a radiation image capturing apparatus installed in a remote hospital or the like is transmitted to the Internet or the like. May be input to the present radiation digital image processing system via the computer network.

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

Reference numeral 12 designates the type of the device which outputs the radiation digital image data in the image data forming unit 10, and transmits the information data indicating the type of the set device to the subsequent photosensor region specifying unit 15 and the image data. This is a setting unit for outputting to the processing unit 17. The setting unit 12 operates the buttons or dials provided on the console, or operates a keyboard, a mouse, or the like, which is an input device of the computer, so that the operator himself / herself can operate. Is configured to directly and manually set the type of device that is outputting radiation digital image data, or, for example, DICOM, which is a standard for digital communication in medicine, forms the radiation digital image data on the radiation digital image data. Since 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. Are devices that output radiation digital image data in accordance with the added information. Determine the type, it is configured to automatically set.

A discriminating unit 13 discriminates 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 discriminated type to the subsequent image processing unit 17. Department. The discriminating unit 13 operates the buttons and dials provided on the console, or operates a keyboard, a mouse, or the like, which is an input device of the computer, so that the operator himself / herself can operate. 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 standard for digital communication in medical care, the radiation digital image data is related to the type of the part indicated by the radiation digital image data. Since the information is added, if the information related to 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 information is added. To determine the type of site indicated by the radiation digital image data according to It has been made.

Reference numeral 14 denotes an output device for outputting radiation digital image data, which is selected from a plurality of types of output devices such as a CRT display device, a film imager device, or a dry printer device. An output device selection unit that outputs information indicating the type of the output device to the image processing unit 17 described below. The output device selection unit 14
The operator himself / herself operates buttons and dials provided on the console, or operates a keyboard, a mouse, or the like, which is an input device of a computer, so that the operator himself / herself can output a plurality of types of output devices. An output device that is configured to directly and manually select a device to be used from among, for example, an output device that is used based on information about a type of a device that outputs radiation digital image data set in the setting unit 12 is used. When preset, the operator does not directly select manually by operating buttons, dials, etc. as described above, but rather information on the type of device that is outputting the radiation digital image data. Is configured to automatically select a preset output device based on the output device.

Reference numeral 15 relates to an image area corresponding to the arrangement position, size, shape, etc. 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. It has a memory table storing information, and based on the information about the type of the device outputting the radiation digital image data set in the setting unit 12, the photo table of the photo sensor on the radiation digital image is read from the memory table. A photosensor area designation unit that reads information about an image area corresponding to an arrangement position, a size, a shape, and the like, and outputs the read information to a feature amount calculation unit 16 at a subsequent stage.

The above-mentioned photosensor is a sensor for detecting the intensity of radiation to be irradiated at the time of radiography. In the radiographic imaging apparatus, the exposure is set so that the exposure at the time of radiography is in a desired state. Exposure of radiation is controlled according to the intensity of radiation detected by the photosensor.

For example, when the radiographic image capturing apparatus is used for radiographing a chest, a photo sensor is arranged at a position where the chest of a patient as a subject contacts, so that an operator can guide a standing position of the patient. , Visually display the position and shape of the photosensor placed on the radiation receiving plate, and adjust the patient's standing position so that the patient's chest is in contact with the display before taking an image. Accordingly, the radiation exposure intensity can be controlled so that the exposure at the time of radiography is appropriate in a region centered on the lung.

When the radiographic image capturing apparatus is for abdominal radiography, as shown in FIG. 2, a photo sensor is disposed at a position (21 in the figure) where the patient's subject, which is the abdomen, hits. An image area (40 mm in width and 40 mm in height indicated by 22 in the figure) that visually indicates the position and shape of the photo sensor arranged on the radiation receiving plate so that the operator can guide the standing position of the patient. Area), and the operator adjusts the patient's standing position to a position where the patient's abdomen contacts the display, and then performs imaging to reduce the exposure during radiation imaging in the area centered on the abdomen. The radiation exposure intensity and time can be controlled to be appropriate.

In the above case, the image area corresponding to the position of the photosensor on the radiation digital image coincides with the display, but as shown in FIG. In order to make it easier for the operator to guide the standing position of the patient, one position (33 in the figure) and a position on the center line of the light receiving plate, 20 each from the center line
5 mm apart at two locations (32, 33 in the figure)
An image area that visually indicates the position and shape of a rectangular photosensor having a length of 0 mm and a length of 90 mm is displayed, and one photosensor is arranged at a position (34 in the drawing) overlapping the image area 33 of the photosensor. The operator adjusts the patient's standing position to a position where the patient's belly contacts the display, and then performs imaging so that the exposure at the time of radiation imaging is appropriate in a region centered on the abdomen. The image area indicating the position of the photo sensor on the radiation digital image, such as a device that controls the exposure intensity and time, does not match the image area where the photo sensor is actually installed. Alternatively, a device in which a photosensor is not actually installed, such as the image regions 31 and 32 in the drawing, may be used.

That is, a radiation imaging technician who is an operator of the radiation digital image processing system instructs a patient to be imaged to take an image in accordance with the arrangement display of the photosensor when performing radiography. The radiation digital image processing system according to an embodiment of the present invention has a habit of guiding a patient to perform radiation imaging so that a part of a subject, which is a subject, matches a position where the photosensor is arranged. In deciding processing conditions in image processing such as density and / or gradation processing to be performed on a photographed radiation digital image, regardless of whether or not photographing was performed using a photo sensor, By utilizing the feature amount of the image area corresponding to the arrangement position, size, shape, etc. of the photo sensor used in the radiation imaging device, the radiation digital Concentration and / or gradation in the image area corresponding to the position of the photo sensor on Le image is one that performs image processing to optimize.

Further, the photo sensor area designating section 15
From the information on the image area corresponding to the arrangement position, size, shape, and the like of the photosensor on the radiation digital image output to the feature amount calculation unit 16, the image area directly cut out from the radiation digital image , Or information data indicating the coordinates indicating the position of the image area on the radiation digital image.

By the way, the image area corresponding to the arrangement position, size, shape, etc. of the photosensor on the radiation digital image does not necessarily need to be different for each radiation imaging apparatus. In addition, the image area corresponding to the position, size, shape, etc. of the photosensor on the radiation digital image may not be completely the same as the shape or position of the actually arranged photosensor. Does not need to match, and may be slightly different from the actual one.

Further, the photo sensor area designating section 15
A memory table that stores information on the position, size, shape, and the like of the photosensor of the radiation digital image capturing apparatus corresponding to the type of the imaging part determined by the determination unit 12; Based on the information on the type of the imaging part determined in step 13, information on the image area corresponding to the arrangement position, size, shape, and the like of the photosensor on the radiation digital image is read from the memory table, and the read information is read. May be output to the feature value calculation unit 16 in the subsequent stage.

Reference numeral 16 denotes a 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 designation unit 15. Based on the information data on the image area corresponding to the arrangement position, size, shape, etc. of the photo sensor, the maximum value, minimum value, average value, median value, mode value, etc. of the pixel value in the image area At least one of the values is used as a feature amount, and a feature amount calculating unit that calculates information on the feature amount outputs information data on the calculated feature amount to the image processing unit 17 at the subsequent stage.

In the feature quantity calculating unit 16, when there are a plurality of (three) image regions corresponding to the positions of the photosensors, for example, when the imaging region is a patient's chest, three characteristic regions are used. The maximum value, the minimum value, or the average value of each of the image regions may be calculated as information data regarding the feature amount, and the calculated information data may be output to the image processing unit 17 at the subsequent stage.

Reference numeral 17 denotes information indicating the type of the radiation imaging apparatus output from the setting unit 12, information on the imaging region output from the discrimination unit 13, and an output device output from the output device selection unit 14. Based on the information indicating the type of the image data and the information on the characteristic amount of the radiation digital image output from the characteristic amount calculation unit 16, the image area corresponding to the position of the photosensor has the optimum density and / or gradation. This is an image processing unit for performing image processing for compressing a dynamic range on the radiation digital image data recorded in the image recording unit 11.

Reference numeral 18 denotes an image output unit.
An output device such as a T display device, a film imager device or a dry printer device, or an interface for outputting a radiation digital image supplied from the image processing unit 17 to an output device connected to a computer network. is there. That is, the image output unit 18 itself does not need to be an output device. For example, radiation image data is supplied to an output device installed in a remote hospital or the like via a computer network such as the Internet. Such a configuration may be used.

Here, the front or side of the patient's chest is photographed using a radiation digital image photographing apparatus in which the photosensor is arranged at the position shown in FIG. 3, and the photographed radiation digital image is printed on a film. The operation of the radiation digital image processing system will be described in detail by taking as an example the case of outputting the data.

First, a radiation digital image corresponding to the radiation image of the front or side of the chest output from the image data forming unit 10 having the radiation digital image photographing apparatus in which the photo sensor is arranged at the position indicated by 34 in FIG. The image data is sent to the image data recording unit 11 and recorded in a semiconductor memory, a hard disk drive, or the like.

On the other hand, when the front or side of the patient's chest is imaged by a radiation digital image photographing apparatus of the type described above, the photosensor area designation section 15
According to the information on the type of the device that is outputting the radiation digital image data set in the, the position, size,
From the memory table that stores information about the image area corresponding to the shape and the like, information about the image area corresponding to the arrangement position, size, shape, and the like of the photosensor in the radiation digital imaging apparatus used for imaging (ie, , Information indicating image areas 31, 32, and 33 in FIG. 3)
Is read out and output to the feature amount calculation unit 16.

In the characteristic amount calculating section 16, of the radiation digital image data supplied from the image data recording section 11,
An image area corresponding to the position of the photosensor is cut out according to the information output from the photosensor area specifying unit 15, and the average value of the pixel values in each of the cutout image areas (here, FIG. , The average of the pixel values in the 33 image area is referred to as Cave, the average of the pixel values in the 32 image area is referred to as Rave, and the average of the pixel values in the 31 image area is referred to as Lave. Is output to the image processing unit 17.

By the way, in the case of this operation example, the setting unit 12
The type of the radiation digital imaging apparatus used for imaging is set in, the imaging part is determined to be the front or side of the chest by the determination unit 13, and the film imager apparatus is selected as the output apparatus by the output apparatus selection unit 14. Therefore, the image processing unit 17 uses the data indicating the average value supplied from the feature amount calculation unit 16 to perform processing so as to perform optimal dynamic range compression.

FIG. 4 is a diagram showing an example of a schematic configuration of the image processing section 17.

As shown in FIG. 4, the image processing unit 17
Determines a density reference value to be used in the dynamic range compression process, generates a data indicating the determined density reference value, a density reference value determination unit 41, determines a compression coefficient, and outputs data indicating the determined compression coefficient. Generated compression coefficient determination unit 42
A smoothing unit 43 for smoothing a radiation digital image represented by the radiation digital image data supplied from the image data recording unit 11 and generating data representing the smoothed radiation digital image; and a density obtained from each unit. A process for compressing the dynamic range of the radiation digital image indicated by the radiation digital image data supplied from the image data recording unit 11 is performed based on the data indicating the reference value, the data indicating the compression coefficient, and the data indicating the smoothed image. And a dynamic range compression processing section 44.

In the image processing unit 17, when the discrimination unit 13 determines that the imaged region is the front of the chest, the density reference value determination unit 41 determines the average value supplied from the feature amount calculation unit 16. “Cave + (Rave−Cave) ×” located between Cave and average value Rave
FIG. 5 shows a value expressed as α, (α is an arbitrary constant set in accordance with the information on the type of the device outputting the radiation digital image data set in the setting unit 12). Density reference value on the function curve shown in FIG.
ASE). Note that the density reference value is “Cave + (Lave−Cabe) located between the average value Cave supplied from the feature amount calculation unit 16 and the average value Lave.
ve) × α ”or a value smaller than the average value Cave.

Then, the compression coefficient determination unit 42 determines the pixel value of the image area indicating the average value Cave supplied from the feature amount calculation unit 16 on the radiation digital image after the dynamic range compression processing by the density reference value determination. In the case where the density reference value is increased by a predetermined value β from the density reference value determined in the unit 41,

[0042]

[Outside 2] (Β is a constant of an arbitrary constant set according to the information on the type of the output device for outputting the radiation digital image data set in the output device selection unit 14.) It is determined as the compression coefficient (SLOPE in the figure) on the function curve shown in FIG.

The smoothing section 43 moves a mask of M pixels × M pixels (M is an arbitrary constant) on the radiation digital image indicated by the radiation digital image data supplied from the image data recording section 11. The average of the pixel values present in the mask at each moving location,
By replacing the obtained average value with the pixel value for which the average value has been obtained, the radiation digital image is smoothed, or data indicating the smoothed radiation digital image is generated,
Alternatively, data representing a radiation digital image smoothed using a morphological filter is generated.

The dynamic range compression processing section 4
_{Reference numeral} 4 denotes a pixel value of the radiation digital image represented by the radiation digital image data supplied from the image data recording unit 11, S ′ _org , and an averaging represented by data representing the smoothed image supplied from the smoothing unit 43. The pixel value of the obtained radiation digital image is S ′ _US , the pixel value of the radiation digital image after the dynamic range compression processing is S ′ _D, and the density reference value (BASE) obtained by the density reference value determination unit 41
Using the data indicating the pixel density value conversion characteristic as shown in FIG.
When (x) is _satisfied , S ′ _D = S ′ _org + f ′ (S _US ) (3) The image data recording unit 11 is calculated by the equation (3).
By performing processing for compressing the dynamic range of the radiation digital image indicated by the supplied radiation digital image data, the dynamic range of the radiation digital image indicated by the radiation digital image data supplied from the image data recording unit 11 is captured. A compression process can be performed in accordance with a dynamic range compression characteristic arbitrarily set according to a part.

In the image processing section 17, when the determination section 13 determines that the imaging region is the side of the chest, the density reference value determination section 41 supplies the image data from the extraordinary amount calculation section 16. Average value Cave × α
(Α is an arbitrary constant set in accordance with the information on the type of the device outputting the radiation digital image data set in the setting unit 12). The density reference on the function curve shown in FIG. The compression coefficient determination unit 42 determines the characteristic amount calculation unit 1 on the radiation digital image after the dynamic range compression processing.
6 so that the pixel value of the image area indicating the average value Rave or the average value Lave supplied from 6 is increased by a predetermined value β from the density reference value determined by the density reference value determination unit 41.

[0046]

[Outside 3] (Β is an arbitrary constant set in accordance with the information on the type of output device for outputting the radiation digital image data set in the output device selection unit 14.) Is determined as a compression coefficient (SLOPE in the figure) on the function curve shown in FIG. 3, and thereafter, the same processing as in the case where the above-described imaging part is in front of the chest is performed, so that the radiation digital signal supplied from the image data recording unit 11 is obtained. A process of compressing the dynamic range of the radiation digital image indicated by the image data according to the dynamic range compression characteristic arbitrarily set according to the imaging region can be performed.

FIG. 7 is a diagram showing another schematic configuration of the image processing section 17.

As shown in FIG. 7, the image processing unit 17
A smoothing unit 70 for smoothing a radiation digital image indicated by the radiation digital image data supplied from the image data recording unit 11 and generating data indicated by the smoothed radiation digital image; Radiation digital image data supplied by the
0, a high-frequency image generation unit 7 that generates data indicating a high-frequency component image in the radiation digital image indicated by the radiation digital image data supplied from the image data recording unit 11 using the data indicating the smoothed image obtained in
1 and a memory table in which function data indicating pixel density value conversion characteristics respectively corresponding to the type of radiographic apparatus, the imaging site and the type of output apparatus are stored in advance, and output from the setting unit 12 from the memory table. Indicating the type of radiation imaging apparatus to be performed, information on the imaging region output from the determination unit 13, and the output device selection unit 1.
The function data indicating the pixel density value conversion characteristic corresponding to the information indicating the type of the output device output from 4 is selected, and the pixel density value conversion curve indicated by the selected function data indicates the desired characteristic. A pixel density value conversion curve determination unit 72 that adjusts and outputs data indicating the adjusted pixel density value conversion curve
And a subject area other than a pass-through portion (a region in which radiation does not pass through the subject and is directly irradiated on a sensor or the like) in the radiation digital image indicated by the radiation digital image data supplied from the image data recording unit 11 is determined. And a subject area determining unit 73 for generating data indicating the determined subject area.
A subject region feature amount generating unit 74 for generating data indicating feature amounts of the subject region based on data indicating the subject region supplied from the subject region determining unit 73; and the subject region feature amount generating unit 74. A density reference value (BASE) used for the dynamic range compression processing is determined based on the data indicating the feature amount of the subject area supplied from
A density reference value determining unit 75 that generates data indicating the determined density reference value, data indicating a pixel density value conversion curve obtained from each unit, data indicating a density reference value, and data indicating a feature amount of a subject area. A compression coefficient determination unit 76 that determines a compression coefficient (R) based on the data, and generates data indicating the determined compression coefficient; data indicating a density reference value obtained from each unit; data indicating a compression coefficient; A dynamic range compression processing unit 77 performs a process of compressing the dynamic range of the radiation digital image indicated by the radiation digital image data supplied from the image data recording unit 11 based on the data indicating the image.

In the image processing section 17, when the discrimination section 13 discriminates that the radiographed region is the front of the chest, first, in the pixel density value conversion curve determination section 72, the type of radiographic apparatus and the radiographed region are determined. From the memory table in which function data indicating the pixel density value conversion characteristic corresponding to each type of the output device or the output device is stored in advance.
Information indicating the type of the radiation imaging apparatus (ie, information indicating the digital radiation imaging apparatus), information regarding the imaging region output from the determination unit 13 (ie, information indicating the front of the chest), and the output Device selection unit 14
Information indicating the type of output device output from
Function data indicating a pixel density value conversion characteristic (curve) as indicated by a broken line in FIG. 8 corresponding to the information indicating the film imager device) is selected.

On the other hand, the average value Cav supplied from the feature amount calculation unit 16 is supplied to the pixel density value conversion curve determination unit 72.
e, Rave, and Lave are supplied, and the average value Rave (or the average value Lave) is set to a desired value set in advance on a pixel density value conversion curve as shown by a broken line in FIG. of so that the lung field density value D _L, adjusted by moving in parallel to the position indicated by the thin line in FIG. 8 in the direction indicated the pixel density value conversion curve by the arrows in FIG. 8, are adjusted Pixel density value conversion curve F _FRO
The data indicating (X) is output to the compression coefficient determination unit 76 and the dynamic range compression processing unit 77.

The subject area determination unit 73 determines, from the radiation image indicated by the radiation digital image data supplied from the image data recording unit 11, a pass-through area where the radiation is directly applied to a sensor or the like without passing through the subject. Is separated, and information data indicating the separated subject region is output to the subsequent subject region feature quantity generation unit 74.

The subject area feature quantity generating section 74 generates a minimum pixel density value _Smin in the subject area based on the information data indicating the subject area supplied from the subject area determining section 73 and generates the minimum pixel density value _Smin. The data indicating the obtained minimum pixel density value _Smin is output to the compression coefficient determination unit 76 as data indicating the feature amount of the subject area.

The density reference value determination unit 75 has the average values Cave and Rav supplied from the feature amount calculation unit 16.
e, the data indicating the LAVE are supplied, the density reference value (BASE) is calculated in accordance with the following equation (4), and the data indicating the calculated density reference value (BASE) is transmitted to the compression coefficient determination unit 76 and the dynamic Output to range compression processing section 77.

BASE = Cave + (Rave−Cave) × α (4)

In the above equation (4), α is an arbitrary constant set in accordance with the information on the type of the device outputting the radiation digital image data set in the setting section.

The compression coefficient determining unit 76 receives data indicating the adjusted pixel density value conversion curve F _FRO (X) indicated by the thin line in FIG. 8 supplied from the pixel density value conversion curve determination unit 72. The data indicating the minimum pixel density value S _min as the feature quantity of the subject area from the subject area feature quantity generation unit 74 is supplied from the density reference value determination unit 75 to the density reference value (B
ASE) is supplied. The compression coefficient determination unit 76 calculates a compression coefficient (R) based on the data supplied from each unit according to the following equation (5), and calculates the calculated compression coefficient (R). R) is output to the dynamic range compression processing unit 77.

[0057]

[Outside 4]

In the above equation (5), D _min
Indicates the minimum pixel density value after the dynamic range compression processing. For the minimum pixel density value _Dmin , a desired arbitrary value of, for example, "0.2" to "0.5" is used.

As described above, the normal pixel density value conversion curve for the front chest radiographed image stored in advance in the memory table in the pixel density value conversion curve determination section 72 is replaced with the pixel density conversion curve. A pixel density value conversion curve F ′ _FRO as shown by a bold line in FIG. 8 in which the slope is attenuated by the compression coefficient (R) in the direction from the density reference value (BASE) to the low density value.
(X) can be obtained.

Then, a dynamic range compression process is performed as described later using the pixel density value conversion curve F ′ _FRO (X) generated as described above, thereby using the ordinary pixel density value conversion curve. The pixel that shows the minimum density value S _min of the subject area on the radiographic image that could not be expressed when the dynamic range compression processing was performed is converted to the dynamic range using the pixel density value conversion curve F ′ _FRO (X). It can be expressed on the radiographic image after the compression processing.

On the other hand, in the image smoothing section 70, M pixels × M pixels (M is an arbitrary number) on the radiation digital image S _org (x, y) indicated by the radiation digital image data supplied from the image data recording section 11. (Constant) size is moved, the average value of the pixel values existing in the mask at each moving position is calculated, and the calculated average value is replaced with the pixel value whose average value is calculated. Smoothing the image and smoothing the digital radiation image S
Data indicating _us (x, y) is generated, and data indicating the generated smoothed radiation digital image S _us (x, y) is output to the high frequency image generation unit 71 at the next stage.

The high-frequency image generator 71 outputs the data representing the radiation digital image S _org (x, y) supplied from the image data recorder 11 and the smoothed radiation supplied from the image smoother 70. Digital image S
Using the data indicating _us (x, y), the radiation digital image S _org indicated by the radiation digital image data supplied from the image data recording unit 11 according to the following equation (6):
Data indicating a high-frequency component image S _hp (x, y) at (x, y) is generated.

S _hp (x, y) = S _org (x, y) −S _us (x, y) (6)

Then, the dynamic range compression processing section 7
7, using the data indicating the density reference value (BASE) supplied from the density reference value determination unit 75 and the data indicating the compression coefficient (R) supplied from the compression coefficient determination unit 76, The adjusted pixel density value conversion curve F _FRO (X) indicated by the thin line in FIG. 8 indicated by the data supplied from the value conversion curve determination unit 72 is converted into a density reference value (BASE) on the pixel density conversion curve. ) To low concentration values,
The gradient is converted into a pixel density value conversion curve F ′ _FRO (X) as shown by a bold line in FIG. 8 in which the slope is attenuated by the compression coefficient (R), and the radiation digital image S supplied from the image data recording unit 11 is further converted. _The dynamic range compression process is performed using data indicating _org (x, y) and data indicating the image S _hp (x, y) of the high-frequency component supplied from the high-frequency image generation unit 71 according to the following equation (7). I do.

[0065]

[Outside 5]

That is, the dynamic range compression processing unit 77 converts the pixel density value S _org (x, y) of the radiation digital image supplied from the image data recording unit 11 into a pixel density value conversion curve according to the above equation (7). F ' _FRO (X)
To the pixel density value F ′ _FRO (S _org (x, y)) according to the following _formula . Further, the high frequency supplied from the high frequency image generation unit 71 according to the inclination of the pixel density value conversion curve F ′ _FRO (X). The dynamic range compression processing is performed by adding the pixel density values S _hp (x, y) of the component images. By performing such dynamic range compression processing, information on high frequency components in the radiation digital image is maintained. The dynamic range compression characteristic for compressing the dynamic range of the radiation digital image can be arbitrarily set according to the imaging region.

In the image processing section 17, if the discriminating section 13 discriminates that the radiographed region is the side of the chest, the pixel density value conversion curve determining section 72 first determines the type of the radiographic apparatus. Information indicating the type of radiation imaging apparatus output from the setting unit 12 from a memory table in which function data indicating pixel density value conversion characteristics corresponding to the type of the imaging apparatus and the type of output apparatus are stored in advance. Information indicating a digital radiation imaging device)
And information on the imaging region output from the determination unit 13 (ie, information indicating the side of the chest), and information indicating the type of output device output from the output device selection unit 14 (that is, information indicating the film imager device). The function data indicating the pixel density value conversion characteristic (curve) as shown by the broken line in FIG.

On the other hand, the average value Cav supplied from the feature amount calculation unit 16 is supplied to the pixel density value conversion curve determination unit 72.
e, Rave, is supplied with data indicating the Lave, said mean value Cave is, the pixel density value conversion on the curve as shown by a broken line in FIG. 9, the density value D _L of the desired lung field which is set in advance as will be, adjusted by moving in parallel to the position shown in the direction indicated the pixel density value conversion curve by an arrow in FIG. 9 by a thin line in FIG. 9, the adjusted pixel density value conversion curve F _LAT ( X) is converted into a compression coefficient determining unit 76 and a dynamic range compression processing unit 77.
Output to

The subject area determining section 73 determines, from the radiation image indicated by the radiation digital image data supplied from the image data recording section 11, a pass-through area in which radiation is directly applied to a sensor or the like without passing through the subject. Is separated, and information data indicating the separated subject region is output to the subsequent subject region feature quantity generation unit 74.

The subject area feature quantity generating section 74 generates and generates a maximum pixel density value S _max in the subject area based on the information data indicating the subject area supplied from the subject area determining section 73. The data indicating the maximum pixel density value _Smax is output to the compression coefficient determination unit 76 as data indicating the feature amount of the subject area.

The density reference value determination section 75 is supplied with data indicating the average value Cave supplied from the feature quantity calculation section 16, and the density reference value (BASE) is calculated according to the following equation (8). Is calculated, and the calculated density reference value (B
ASE) is output to the compression coefficient determination unit 76 and the dynamic range compression processing unit 77.

BASE = S _max + (S _max −Cave) × β (8)

In the above equation (8), β is an arbitrary constant set in accordance with the information on the type of the device outputting the radiation digital image data set in the setting section.

The compression coefficient determining unit 76 receives data indicating the adjusted pixel density value conversion curve F _LAT (X) indicated by the thin line in FIG. 9 supplied from the pixel density value conversion curve determination unit 72. The data indicating the maximum pixel density value _Smax as the feature value of the subject area from the subject area feature value generation unit 74 is supplied from the density reference value determination unit 75 to the density reference value (B
ASE) is supplied. The compression coefficient determination unit 76 calculates a compression coefficient (R) based on the data supplied from each unit in accordance with the following equation (9), and calculates the calculated compression coefficient (R). R) is output to the dynamic range compression processing unit 77.

[0075]

[Outside 6]

In the above equation (9), D _max
Indicates the maximum density value after the dynamic range compression processing. The maximum density value _Dmax includes, for example, "2.
Any desired value from 7 "to" 3.0 "is used.

As described above, the normal pixel density value conversion curve for the chest side photographed image stored in advance in the memory table in the pixel density value conversion curve determination section 72 is converted to the pixel density conversion curve. A pixel density value conversion curve F ′ _LAT as shown by a bold line in FIG. 9 in which the slope is attenuated by the compression coefficient (R) from the density reference value (BASE) to the high density value direction.
(X) can be obtained.

Then, a dynamic range compression process is performed as described later using the pixel density value conversion curve F ′ _LAT (X) generated as described above, thereby using the ordinary pixel density value conversion curve. A pixel indicating the maximum pixel density value _Smax of the subject area on the radiographic image, which could not be expressed when the dynamic range compression processing was performed, is determined using the pixel density value conversion curve F ′ _LAT (X). It can be expressed on the radiographic image after the range compression processing.

Hereinafter, the dynamic range compression processing unit 77
In the above, by performing the same processing as in the case where the above-mentioned imaging part is the side of the chest, the dynamic range of the radiation digital image is maintained while maintaining the information of the high frequency component in the radiation digital image data supplied from the image data recording unit 11 Can be compressed in accordance with a dynamic range compression characteristic arbitrarily set in accordance with the radiographic image of the radiation digital image.

As described above, the radiation digital image data subjected to the optimum dynamic range compression processing in the image processing unit 17 is supplied to the image output unit 18, and the image output unit 18 outputs the digital image data. By printing a radiation digital image on a film at a laser intensity corresponding to the pixel value indicated by the supplied radiation digital image data, the radiation whose dynamic range is compressed according to an arbitrary dynamic range compression characteristic at an optimum density for the film. A digital image can be formed.

In the above-described operation example, the case where the imaging part is the “chest” has been described as an example. However, for example, when the imaging part is the “abdomen”, the photo indicated by 31, 32, and 33 in FIG. The feature amount of the image may be calculated from the entire image area corresponding to the position of the sensor, and a dynamic range compression process may be performed based on the calculated feature amount. The feature amount of the image may be calculated only from the image region corresponding to the position of the photosensor indicated by 22 or 33 in FIG. 3, and the dynamic range compression processing may be performed based on the calculated feature amount. Further, in this case, it is not necessary to use the radiation image capturing apparatus in which the photo sensors are arranged at all the positions indicated by 31, 32, and 33 in FIG. 3, and as shown in FIG. The digital radiation imaging can be performed by the radiation image capturing apparatus in which the photo sensor is arranged only at the position shown in FIG.

[0082]

As described above, according to the present invention,
In order to obtain the same image processing effect in the image area corresponding to the position of the photosensor on various radiation digital images, where the radiographed part, the physique of the subject, and the radiation dose at the time of radiography differ, A radiation digital image processing system capable of automatically performing optimal image processing on a radiation digital image without any trouble can be provided.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining an installation position of a photosensor in a radiographic image capturing apparatus for abdominal image capturing of the digital radiation image system illustrated in FIG. 1;

FIG. 3 is a diagram for explaining an installation position of a photosensor in a radiographic image capturing apparatus for chest radiography of the digital radiation image processing system shown in FIG. 1;

FIG. 4 is a diagram illustrating a schematic configuration example of an image processing unit of the radiation digital image processing system illustrated in FIG. 1;

FIG. 5 is an explanatory diagram of a pixel density value conversion characteristic at the time of front chest imaging.

FIG. 6 is an explanatory diagram of a pixel density value conversion characteristic at the time of imaging the side of the chest.

FIG. 7 is a diagram illustrating another schematic configuration example of the image processing unit of the radiation digital image processing system illustrated in FIG. 1;

FIG. 8 is an explanatory diagram of pixel density value conversion characteristics at the time of front chest imaging.

FIG. 9 is an explanatory diagram of a pixel density value conversion characteristic at the time of imaging the side of the chest.

FIG. 10 is a diagram for explaining a conventional dynamic range compression method.

[Explanation of symbols]

 Reference Signs List 10 image data forming unit 11 image data recording unit 12 setting unit 13 discriminating unit 14 output device selecting unit 15 photosensor area specifying unit 16 feature amount calculating unit 17 image processing unit 18 image output unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C093 AA26 CA16 CA17 CA50 DA01 EB05 EB13 EE01 FD01 FD03 FD08 FF06 FF08 FF18 FF19 FF27 FG04 FG05 FH06 5C072 AA01 RA06 RA20 UA06 UA11 UA17 PP01 PP01 PP01 PP01 PP58 PP68 PQ08 PQ23 RR01 TT02

Claims (23)

[Claims] An input unit for inputting digital radiation image data obtained by digitizing an image obtained by radiography, and an intensity at the time of radiography on the radiographic digital image indicated by the digital radiation image data input by the input unit. A photosensor area designating unit that designates an image area corresponding to the arrangement position of the photosensor for detection, and an image area corresponding to the arrangement position of the photosensor on the digital radiation image designated by the photosensor area designation unit. A feature amount generating unit configured to generate a feature amount, and a radiation indicated by the radiation digital image data with respect to the radiation digital image data input by the input unit according to information on the feature amount generated by the feature amount generating unit. Control the dynamic range of digital images Image processing means for performing image processing, and image output means for visualizing and outputting a radiation digital image corresponding to the radiation digital image data subjected to image processing in the image processing means. Processing system. 2. The radiation digital image processing system according to claim 1, further comprising recording means for recording radiation digital image data input by said input means. 3. The radiation digital image processing system according to claim 1, wherein the feature amount is a maximum value, a minimum value, or an average value of pixel values in an image area. 4. An image processing apparatus according to claim 1, wherein said image processing means performs a pixel density used when performing an image processing for compressing a dynamic range of the radiation digital image indicated by said radiation digital image data on said radiation digital image data inputted by said input means. 2. The radiation digital image processing system according to claim 1, wherein a value of a change point in the value conversion curve is set in accordance with information on a feature amount generated by the feature amount generation unit. 3. 5. The image processing apparatus according to claim 1, wherein the image processing unit performs image processing on the radiation digital image data input by the input unit to compress a dynamic range of the radiation digital image represented by the radiation digital image data. 2. The radiation digital image processing system according to claim 1, wherein a slope before and after a change point in the value conversion curve is set in accordance with information on the feature amount generated by the feature amount generation unit. 3. 6. The radiation digital image processing system according to claim 1, further comprising a setting unit that sets a type of a source of the radiation digital image data input by the input unit. 7. The method according to claim 1, wherein the setting unit automatically sets the type of the source according to information about the type of the source added to the radiation digital image data input by the input unit. Item 6. A radiation digital image processing system according to item 5. 8. The radiation sensor according to claim 1, wherein the photosensor area designating unit is configured to perform radiation imaging on the radiation digital image indicated by the radiation digital image data input by the input unit in accordance with the information on the type of the source set by the setting unit. The radiation digital image processing system according to claim 5, wherein an image area corresponding to a position where a photosensor for detecting the intensity of the image is detected is designated. 9. The apparatus according to claim 1, wherein the image processing unit is configured to generate information on the type of the source set by the setting unit and the feature generated by the feature amount generating unit with respect to the radiation digital image data input by the input unit. 6. An image processing for controlling a dynamic range of a radiation digital image according to the information related to the amount.
3. A radiation digital image processing system according to claim 1. 10. The image processing means includes a look-up table storing data indicating a pixel density value conversion curve for converting a pixel density value of a radiation digital image in correspondence with a type of a source. In accordance with the information on the type of the source set by the means, data indicating a corresponding pixel density value conversion curve is read from the look-up table, and the input means uses the data indicating the read pixel density value conversion curve. The radiation digital image processing system according to claim 5, wherein image processing for controlling a dynamic range of the radiation digital image is performed on the input radiation digital image data. 11. The image processing means includes a look-up table storing data indicating a standard pixel density value conversion curve for converting a pixel density value of a radiation digital image in association with a type of a source. In accordance with the information on the type of the source set by the setting means, data indicating a corresponding standard pixel density value conversion curve is read from the look-up table, and the standard pixel density value conversion curve indicated by the read data is further set as described above. Radiation adjusted by the information on the type of the source set by the means and the information on the feature generated by the feature generating means, and input by the input means using the adjusted pixel density value conversion curve Applying image processing to the digital image data to control the dynamic range of the radiation digital image The radiation digital image processing system according to claim 5, wherein 12. The radiation digital image processing system according to claim 1, further comprising: a determination unit configured to determine an imaging region of a radiation digital image indicated by the radiation digital image data input by the input unit. 13. The apparatus according to claim 12, wherein the determination unit automatically determines an imaging region according to information on an imaging region added to the radiation digital image data input by the input unit. Radiation digital image processing system. 14. The photosensor area designating means,
Arrangement of a photosensor for detecting the intensity of radiation at the time of radiography on a radiation digital image indicated by the radiation digital image data input by the input means according to the information on the imaging site of the radiation digital image determined by the determination means The radiation digital image processing system according to claim 12, wherein an image area corresponding to the position is specified. 15. The apparatus according to claim 1, wherein the image processing unit is configured to determine, with respect to the radiation digital image data input by the input unit, information on an imaging part determined by the determination unit and a feature amount generated by the feature amount generation unit. 13. An image processing device for controlling a dynamic range of a digital radiation image according to information.
3. A radiation digital image processing system according to claim 1. 16. The image processing means includes a look-up table storing data indicating a pixel density value conversion curve for converting a pixel density value of a radiation digital image in correspondence with a type of a source. According to the information on the imaging region determined by the means, data indicating a corresponding pixel density value conversion curve is read from the look-up table, and is input by the input means using the data indicating the read pixel density value conversion curve. 13. The radiation digital image processing system according to claim 12, wherein image processing for controlling a dynamic range of the radiation digital image is performed on the radiation digital image data. 17. The image processing means includes a look-up table storing data indicating a standard pixel density value conversion curve for converting a pixel density value of a radiation digital image in correspondence with a type of a source. According to the information on the imaging region determined by the determination unit, data indicating a corresponding standard pixel density value conversion curve is read from the lookup table, and the standard pixel density value conversion curve indicated by the read data is further determined by the determination unit. The radiation digital image data input by the input unit using the adjusted pixel density value conversion curve, adjusted according to the information regarding the determined imaging part and the information regarding the characteristic amount generated by the characteristic amount generation unit. On the other hand, image processing for controlling a dynamic range of a radiation digital image is performed. 13. The radiation digital image processing system according to claim 12. 18. The radiation digital image processing system according to claim 1, further comprising output device selecting means for selecting a type of said radiation digital image output device. 19. The apparatus according to claim 19, wherein the output device selection unit automatically sets a radiation digital image output device preset according to the type of the source according to the type of the source of the radiation digital image data input by the input unit. 19. The radiation digital image processing system according to claim 18, wherein: 20. A radiation digital apparatus according to claim 1, wherein said output device selecting means is configured to set the radiation digital data in accordance with the type of the radiation source in accordance with the information on the radiation source type added to the radiation digital image data input by said input means. 19. The radiation digital image processing system according to claim 18, wherein an image output device is automatically selected. 21. The image processing means, for the radiation digital image data input by the input means, information on the type of the radiation digital image output device selected by the output device selection means and the feature quantity generation means 20. The radiation digital image processing system according to claim 18, wherein image processing for controlling a dynamic range of the radiation digital image according to the information on the feature amount generated in the step is performed. 22. The image processing means includes a look-up table storing data indicating a pixel density value conversion curve for converting a pixel density value of a radiation digital image in correspondence with a type of a source. According to the information on the type of the radiation digital image output device selected by the device selecting means, data indicating a corresponding pixel density value conversion curve is read from the lookup table, and data indicating the read pixel density value conversion curve is used. 19. The radiation digital image processing system according to claim 18, wherein the radiation digital image data input by the input unit is subjected to image processing for controlling a dynamic range of the radiation digital image. 23. The image processing means includes a look-up table storing data indicating a standard pixel density value conversion curve for converting a pixel density value of a radiation digital image in correspondence with a type of a source. In accordance with the information about the type of the radiation digital image output device selected by the output device selection means, data indicating a corresponding standard pixel density value conversion curve is read from the lookup table, and the standard pixel density value conversion indicated by the read data is read. The curve is further adjusted in accordance with the information on the type of the radiation digital image output device selected by the output device selection unit and the information on the feature amount generated by the feature amount generation unit, and the adjusted pixel density value conversion curve is obtained. The radiation digital image data input by the input means using the radiation digital image The radiation digital image processing system according to claim 18, wherein image processing for controlling a dynamic range of an image is performed.