JPH0247778A - Radiographic image processor - Google Patents

Abstract

PURPOSE:To obtain plural image signals whose spatial frequencies to be emphasized are different without decreasing the processing ability of a device by simultaneously obtaining plural blur masking signals at every picture element with a blur masking arithmetic processor. CONSTITUTION:Picture processing units 14 and 15 are connected through an interface unit 13 to a radiographic image reader. The picture processing unit 14 is equipped with a buffer 14a to temporarily accumulate an original picture signal, and a blur masking arithmetic processor 14b to obtain the plural blur masking signals to have changed prescribed picture element ranges at every picture element. An arithmetic processor 15a of the picture processing unit 15 executes an arithmetic processing by using the respective plural blur masking signals, and obtains plural arithmetic processing image signals.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a radiation image processing device that inputs an original image signal representing a radiation image and performs spatial frequency processing and gradation processing on this image signal. .

(Prior Art) It is practiced in various fields to read a recorded radiation image to obtain an image signal, perform appropriate image processing on the image signal, and then reproduce and record the image. For example, an X-ray image is recorded using an X-ray film with a low gamma value designed to be compatible with later image processing, and the X-ray image is read from the film on which it is recorded and converted into an electrical signal. After converting the electric signal (image signal) and performing image processing, it is possible to obtain a reproduced image with good image quality performance such as contrast, sharpness, and graininess by reproducing it as a visible image in a photocopy etc. A system that can do this has been developed (see Japanese Patent Publication No. 61-5193).

In addition, the applicant has proposed radiation (X-rays, α-rays).

When irradiated with β rays, γ rays, electron beams, ultraviolet rays, etc., a part of this radiation energy is accumulated, and then when irradiated with excitation light such as visible light, stimulable fluorescence exhibits stimulated luminescence depending on the accumulated energy. Radiographic image information of a subject such as a human body is partially recorded on a sheet of stimulable phosphor using a stimulable phosphor, and this stimulable phosphor sheet is scanned with excitation light such as a laser beam. The resulting stimulated luminescent light is read photoelectrically to obtain image data, and based on this image data, a radiation image of the subject can be recorded on a recording material such as a photographic light-sensitive material, a CRT, etc. A radiation image recording and reproducing system that outputs visual images has already been proposed (Japanese Unexamined Patent Publication No. 5
No. 5-12429, No. 5B-11,395.

No. 55-11340, No. 5B (No. 04845, No. 55)
-116340 etc. ) This system has the practical advantage of being able to record images over a much wider range of radiation exposure compared to conventional radiographic systems using silver halide photography. In other words, in a stimulable phosphor, it is recognized that the amount of emitted light that is stimulated to emit light due to excitation after accumulation is proportional to the amount of radiation exposure over an extremely wide range.
Therefore, even if the amount of radiation exposure varies considerably due to various imaging conditions, the amount of stimulated luminescence emitted from the stimulable phosphor sheet can be read by the photoelectric conversion means by setting the reading gain to an appropriate value. To obtain a radiation image that is not affected by fluctuations in radiation exposure by converting it into an electric signal and using this electric signal to output the radiation image as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT. Can be done.

A system that outputs a visible image using a recording sheet such as an X-ray film or a stimulable phosphor sheet described above usually includes an imaging device that captures and records a radiation image of a subject on the recording sheet, and a radiographic device that records the radiation image recorded on the recording sheet. A radiation image reading device that reads and obtains an original image signal S org, inputs the original image signal S org and reads the image signal S or
A radiation image processing device that obtains a calculation-processed image signal 5cal by subjecting g to appropriate calculation processing such as frequency processing and gradation processing, and a radiation image reproduction device that outputs a radiation image as a visible image based on the calculation-processed image signal 5cal. Consists of equipment.

In the radiation image processing device, the original image signal So
rg (each original image signal corresponding to each pixel 1 (i is a positive integer) of the radiation image is converted into a pixel signal Sorg
CI). ) to the arithmetic processing image signal 5cal (
The arithmetic processing image signal corresponding to each pixel 1 is called a pixel processing signal S cal (i). As a calculation processing method normally used to obtain ), first, the blur mask signal S us (i) corresponding to each pixel 1 is obtained by averaging the pixel signals within a predetermined image range around each pixel 1, and ( This is called blur mask processing.) Then, the emphasis coefficient that determines the degree of emphasis or attenuation of a specific spatial frequency component of the image is set to β (including the case where a specific spatial frequency component of the image is attenuated (β = 0)). , when the tone coefficient that determines the tone of the image is γ, the formula S cal (i) = 7 (S org (i) +
β (S org(i)-S us(i) ))...
... A method has been used in the past to obtain the arithmetic processed image signal 5eal by sequentially performing the arithmetic processing according to (i) for each pixel l (for example, Japanese Patent Publication No. 62-62373, Japanese Patent Publication No. 62-62374, Japanese Patent Application No. 82-265017, No. 82-285018, No. 63-88751, No. 83-86752, etc.).

The radiation image processing device performs the blur mask processing and (i
) In order to perform arithmetic processing according to the equation (
i) a processor that performs calculations according to the formula, temporarily stores sequentially input original image signals (pixel signals) in the buffer, and calculates a blur mask signal 5us(f) around pixel l. When the possible range of image signals has been stored in the buffer, the blur mask signal Sus (i) corresponding to the pixel I is obtained, and then the pixel processing signal S cal ( I was looking for i).

In a radiation image reproducing device, for example, a conventional image that is almost the same as an image recorded on conventional X-ray film and an image that has been subjected to image processing to be more suitable for observation are output side by side. A plurality of visible images corresponding to one radiographic image may be output side by side. At this time, in the radiation image processing apparatus, a plurality of arithmetic processing image signals 5 corresponding to the number of visible images output from the original image signal S org corresponding to one radiation image are processed.
eal 1, 5eal 2, -, 5caln (
n is an integer greater than or equal to 2) is generated.

A plurality of arithmetic processing image signals 5eal, 5eal
□.

... When calculating 5caln, conventionally only one blur mask signal 5us (a set of blur mask signals 5us(j) corresponding to each pixel l) was used. That is, one blur mask signal Sus is obtained, and a plurality of arithmetic processed image signals 5ea11, 5e are obtained by calculating the equation (i) while changing the values of the emphasis coefficient β and/or the gradation coefficient γ.
al Z , -, Sea! n is calculated, and each arithmetic processing image signal 5cal 1°Sea! is calculated in the radiation image reproducing device.
□,...r A plurality of visible images based on each of the 5 cals were reproduced and output.

(Problem to be Solved by the Invention) As described above, a plurality of arithmetic processing image signals 5eal 1 and 5eal 2 are generated using one blur mask signal Sus.
.

. . . When calculating 5caln, the two images, the previously familiar image that is almost the same as the image recorded on conventional X-ray film and the image that has been subjected to image processing to make it more suitable for observation, are placed side by side. However, even if the value of the emphasis coefficient β is changed, the emphasized spatial frequency does not change, only the degree of emphasis changes. This method has the disadvantage that it cannot meet the demand for simultaneously outputting two visible images.

In addition, for example, in systems used to diagnose human diseases, it may be more effective to observe multiple visible images with different emphasis spatial frequencies side by side when examining the symptoms of the disease being diagnosed in detail. I've come to understand that.

In order to deal with this, a plurality of arithmetic processing images 5eal 1 , 5ea12 , which have different spatial frequencies to be emphasized are used.
..., 5caln needs to be calculated, and for this purpose, at the stage of blur mask processing, the degree of averaging (spatial frequency component Multiple blur mask signals with varying degrees of emphasis) 5us1+ 5uS2+
..., find 5usn, and add emphasis coefficient β as necessary.
, the value of the gradation coefficient γ must also be changed and arithmetic processing must be performed according to equation (i).

Multiple blur mask signals 5us1, 5usz,...
・To obtain 5 usn, increase the capacity of the buffer and use the original image signal 5 corresponding to one entire radiation image.
Input the entire eal into the buffer, perform blur mask processing and (i
) can be realized by alternately repeating the arithmetic processing according to the formula a plurality of times. However, it has been reported that performing calculations sequentially in this manner takes too much time and reduces the throughput of the entire system per unit time.

Furthermore, it is provided with a plurality of sets of the above-mentioned buffers and processors, and a plurality of blur mask signals 5usl, 5us2, . . .
The operations for obtaining 5 usn are performed simultaneously in parallel, and (i
) can also be performed in parallel.

However, if this method is adopted, a plurality of arithmetic processing image signals 5eatl, 5car2,
. . . Since the same number of buffers and processors as 5 cals are required, there is a problem that the device becomes complicated and the cost increases.

In view of the above-mentioned circumstances, the present invention provides a method for processing a plurality of arithmetic processing image signals 5ea with different emphasized spatial frequencies without reducing the processing capacity of the device and with a minimum increase in cost.
It is an object of the present invention to provide a radiation image processing device capable of determining l 1 , 5eal 2, -, 5caln.

(Means for Solving the Problems) The radiation image processing device of the present invention provides
(i is a positive integer) corresponding pixel signal Sorg
Original image signal S or (i) arranged in chronological order
g is input, emphasis coefficient is β, tone coefficient is γ, each pixel is 1
The blur mask signal corresponding to each pixel l obtained by averaging the pixel signals within a predetermined pixel range around is Sus(i), and the image signal after calculation processing corresponding to each pixel l is the pixel processed signal S cal (i), the arithmetic processing according to formula 3 % (i) is sequentially performed for each pixel l to obtain an arithmetic processed image signal 5 in which pixel processed signals S cal (i) are arranged.
In a radiation image processing apparatus that calculates eal, a buffer temporarily stores an original image signal S org, and a plurality of blur mask signals 5usl (i), 5US2 (i) in which a predetermined pixel range is changed for each pixel l.

..., a blur mask calculation processor that calculates 5usn(i) (n is an integer of 2 or more), and the plurality of blur mask signals 5us1(i), 5usz(i),
-, 5usn(i) are used to perform the above arithmetic processing, and a plurality of arithmetic processed image signals 5eal 1 , 5
and an arithmetic processing processor for calculating eal 2, -, 5 caln, and the blur mask arithmetic processor calculates the original image signal S.
A plurality of blur mask signals 5usl (i), 5usz (i) + -5 corresponding to each pixel 1 in org.
When the final pixel signal from which all of usn(i) can be determined is input to the buffer, each pixel l
A plurality of blur mask signals 5usl(i) corresponding to
This method is characterized in that it calculates 5usz (i), -, 5usn(i).

Here, the above-mentioned emphasis coefficient β also includes a case where β is O, that is, a case where a specific spatial frequency component is attenuated.

(Function) The radiation image processing apparatus of the present invention includes a blur mask calculation processor that performs blur mask processing, and the blur mask calculation processor processes a plurality of blur mask signals 5us1(i) corresponding to each pixel l.

When the final pixel signal from which all of 5us2 (i), -, 5usn(i) can be obtained is input to the buffer, a plurality of blur mask signals 5usl (i), 5usz (i ), −,
Since it is configured to calculate 5usn(i), there are multiple (n) pairs of buffers and processors! Multiple blur mask signals 5us1(i) for each pixel
.

5us2(i), -, 5usn(i) can be obtained simultaneously.

In addition, the plurality of blur mask signals Sus! (i).

5us2 (i), =z 5usn(i) is sent to the arithmetic processor simultaneously for each pixel, and (i)
A plurality of pixel processing signals 5eal 1 (i), 5cal 2 (i), corresponding to each pixel l according to the formula
-, 5caln(i) is obtained.

(Example) Examples of the present invention will be described below.

FIG. 2 is a perspective view of an embodiment of a radiation image reading device connected to the radiation image processing and display device according to the present invention.

This device uses the stimulable phosphor sheet described above.

In a photographing device (not shown), a subject such as a human body is irradiated with radiation and photographed, and a radiation image of the subject is stored and recorded on a stimulable phosphor sheet.

The stimulable phosphor sheet 6D on which this photographing was performed is
It is set at a predetermined position of the radiation image reading device 30 shown in the figure.

The stimulable phosphor sheet θ1 set in this manner is transported (sub-scanning) in the direction of arrow Y by a sheet transport means 63 such as an endless belt driven by a motor 62. On the other hand, excitation light 65 emitted from the laser light source 64
is reflected and deflected by a rotating polygon mirror 66 that is driven by a motor 73 and rotates at high speed in the direction of the arrow. After passing through a focusing lens 67 such as a θ lens, the optical path is changed by a mirror 68 and enters the sheet 61 for the sub-scanning. direction (arrow Y
Main scanning is performed in the direction of arrow X, which is substantially perpendicular to the main direction. From the part of the sheet B1 irradiated with this excitation light 65, stimulated luminescence light 69 of a light amount according to the radiation image information stored and recorded is emitted.
is emitted, and this stimulated luminescence light 89 is guided by a light guide 70 and passed through a photomultiplier (photomultiplier tube) 71.
is detected photoelectrically by The light guide 70 is made by molding a light guiding material such as an acrylic plate,
The linear incident end surface 70a is the stimulable phosphor sheet 61.
The photomultiplier 7 is disposed so as to extend along the upper main scanning line and is disposed on an annular output end surface 70b.
1 light-receiving surfaces are combined. The stimulated luminescent light 69 that has entered the light guide 70 from the incident end surface 70a travels through the interior of the light guide 70 by repeating total reflection, and then reaches the exit end surface 70.
The light is emitted from b and is received by the photo multiplier 71,
A photomultiplier 71 detects the amount of stimulated luminescence light 69 carrying the radiation image information. Analog signal S output from photomultiplier 71 is amplified by amplifier 7B and digitized by A/D converter 77. The digital original image signal Sorg thus obtained is a set of a large number of pixel signals Sorg(i) corresponding to each pixel 1 of the radiation image. Once stored in the memory 78, the original image signal S org thus obtained is transmitted to the transmitting means 7
8, each pixel signal is sequentially transmitted in time series to a radiation image display device to be described later.

FIG. 3 is a diagram showing an example of the configuration of a radiation image processing display device incorporating an example of the radiation image processing device of the present invention.

This radiation image processing and display device 10 includes a central processing unit (hereinafter abbreviated as CPU) 11, a main memory 2 which is composed of an IC memory, etc., and stores running programs and various flags, Image reading device 30
is connected to the interface unit 13, and two image processing units (hereinafter referred to as
(abbreviated as ALU) 14.15, console CRT display control unit 1B to which console CRT display lea is connected, console keyboard 17a
console keyboard control unit 17 connected to
．． 4 CRT displays for image display 18a s 1
CRT display control unit 18.19.2 for image display to which 9a%20a and 21a are connected respectively
0.21.Two magnetic disk units (hereinafter referred to as DIS
(abbreviated as K) 22 and 23, and the above-mentioned units 11 to 23 are connected to each other by a pass line 24.

The CPU 1l controls each unit 13 to 23 according to a program stored in the main memory 12.

The console CRT display control unit 16, the console CRT display Leas, the console keyboard control unit 17, and the console keyboard 17a are used to check the operating state of the device 10, give instructions for its operation, and the like.

Further, the DISK 23 is used for storing programs, and the programs stored in the DISK 23 are transferred to the main memory 12 and executed.

The image signal S org inputted from the radiation image reading device 30 via the interface unit 13 is first inputted to the ALU 14 where it is subjected to blur mask processing, and then inputted to the ALU 15 where it is inputted to the arithmetic processing formula according to equation (i). FIG. 1A is a block diagram showing the main internal parts of the image processing unit 14 and 15 shown in FIG.
FIG. 2 is a diagram showing an arrangement structure of image signals accumulated in the buffer shown in the figure.

Original image signal Sorg input from the radiation image reading device 30 via the interface unit ■3
is input to buffer 14a along path A shown in FIG. 1A. Within the buffer 14a, the main scanning line 1 is arranged so that the arrangement of pixel signals is basically the same as the arrangement of each pixel of the radiation image read by the radiation image reading device 30, as shown in FIG. 1B. ．． 2. 3. ···,Response,
. . 1 m, . . . Pixel signals corresponding to each pixel arranged in the X direction (corresponding to the X direction in Fig. 2), pixel signals corresponding to each pixel arranged in the sub-scanning direction are Second
(corresponding to the X direction in the figure). However, since the capacity of the buffer in this embodiment is only m in the X direction, the pixel signal corresponding to main scanning line m+1 corresponds to each pixel on main scanning line 1 in the storage part corresponding to main scanning line 1. is accumulated in place of the pixel signal for main scanning line m+2.
The pixel signal corresponding to the main scanning line 2 is accumulated in the accumulation portion corresponding to the main scanning line 2 in place of the pixel signal corresponding to each pixel on the main scanning line 2, and is subsequently accumulated sequentially in the same manner.

In this embodiment, the blur mask calculation processor 14b calculates, for each pixel 1, a blur mask signal 5usl (i) obtained by averaging the pixel signals corresponding to each pixel in the area a, and a pixel signal corresponding to each pixel in the area a. An averaged blur mask signal 5usz (i) is obtained.

At the time when the pixel signal S org (x) corresponding to the pixel ) becomes possible. However, the blur mask signal 5us
The point in time when the calculation of z (i) becomes possible, that is, the pixel y
The pixel signal s org(y) corresponding to buffer 1
4a (pixel signal S org(x)
This calculation is not performed until after the time when the data is accumulated. When the pixel signal s org (y) corresponding to pixel y is accumulated in the buffer, the pixel signal corresponding to each pixel in the area is read out along path B to the blur mask calculation processor 14b, Two corresponding blur mask signals 5usl (i), 5us2 (i
) is required.

When the two blur mask signals 5usl(i) and 5usz(i) are obtained by the blur mask calculation processor 14b, these two blur mask signals 5uss(i),
5 usz (i) and pixel signal S cal (
i) is input to the arithmetic processing processor 15a along path C. The arithmetic processing processor 15a uses two preset emphasis coefficients β1. β2 and two tone coefficients 7
1°γ2, the two pixel processing signals 5eal
1 (i), 5eal z (i) is the formula%formula%
(i) Calculated based on: Equation (2) corresponds to, for example, arithmetic processing that is suitable for overviewing the radiation image as a whole, and Equation (3) corresponds to, for example, arithmetic processing that makes a particular part of the radiation image optimal for observation. are doing.

Two pixel processing signals 5eal t (i) and 5eal z obtained by the arithmetic processing processor 15a
(i) is transferred to and stored in the DISK 22.

The blur mask process corresponding to pixel l is completed, and buffer 1 is
4a, the pixel signal S or corresponding to pixel y''+1
When g(y+1) is accumulated, the calculation corresponding to pixel 1+1 is started.

In this way, in the embodiment shown in FIG.
Two arithmetic processing image signals 5ea using LU14.15
I'm looking for l l, 5eal 2, but two A
In each of LU14.15, blur mask signals 5USI (i) and 5usz (i) are sent in parallel.
is calculated, and the arithmetic processing image signals 5eal 1, 5 are calculated in parallel.
Compared to calculating each of cal□, the time required for the calculation process is almost the same, and the cost of the device is reduced because there is no need to provide a buffer in the ALU 15.

In addition, three types of arithmetic processing image signals 5call, 5cal
When calculating z, 5eal 3, three AL
To perform operations in parallel using U, use ALU14,
Although it is necessary to further equip the ALU 15 with a buffer and another ALU equipped with a buffer and a processor, in this embodiment, it is possible to deal with this with the configuration shown in FIG. 1A, and three units can be used. The cost reduction is greater than when two ALUs are operated in parallel.

DISK 2 which has been subjected to appropriate image processing as described above
Two arithmetic processing image signals 5cal t stored in 2
, 5eal z are transferred from the DISK 22 to any two of the image display CRT display control devices 18 to 21, and the image display CRT display 1
Arithmetic processing image signal 5ea is sent to any two of 8a to 21a.
Two visible images based on each of l L and 5eal 2 are played back and displayed.

Image display CR to which the radiation images to be compared are connected
If the number is within the number of T displays 18a to 21a, they will be played back and displayed simultaneously, and when comparing a large number of radiographic images, the first to fourth images will be displayed on the CRT displays 18a to 21a, respectively, and then the steps in Section 5 will be performed. Image first
The images are sequentially displayed on the CRT display 18a instead of the images shown in FIG.

In this embodiment, the arithmetic processing image signals 5ea11.
Although a visible image based on 5calz is displayed on a CRT display, it goes without saying that it may also be reproduced and recorded on a photosensitive film using, for example, a laser beam.

In addition, in this embodiment, an original image signal S org representing a radiation image accumulated and recorded on a stimulable phosphor sheet is used.
The present invention is applicable not only to a system using a stimulable phosphor sheet but also to a system that performs image processing on an image signal obtained from a radiation image recorded on an X-ray film, etc. The present invention can be applied to various radiation image processing apparatuses that perform image processing on image signals representing .

(Effects of the Invention) As described above in detail, the radiation image processing apparatus of the present invention includes a buffer that temporarily stores the original image signal Sorg, and a plurality of blur mask signals whose predetermined pixel ranges are changed for each pixel l. 5us1 (i).

A blur mask calculation processor that calculates 5us2 (i) , -, 5usn (i) (n is an integer of 2 or more), and the plurality of blur mask signals 5ust (i) , 5usz
(i) , ・=Susn(i) are used to perform arithmetic processing, and a plurality of arithmetic processed image signals 5eat
1, 5eal2,...5caln, and the blur mask calculation processor calculates a plurality of blur mask signals 5us1 (i), 5 corresponding to each pixel I of the original image signal s org.
When the final pixel signal from which all of LIS2 (i), . 5 usz (i)
, -,5usn(i), a plurality of arithmetic processed image signals with different emphasized intersection angle frequencies can be generated without reducing the processing capacity of the device and with a slight increase in cost. Thereby, a plurality of visible images that are more suitable for the purpose of comparative observation can be reproduced and displayed side by side.

[Brief explanation of the drawing]

FIG. 1A shows the image processing unit 14.15 shown in FIG.
Figure 1B is a block diagram showing the main internal parts of the
FIG. 2 is a perspective view of an embodiment of the radiation image reading device; FIG. 3 is an example of the radiation image processing device of the present invention. 1 is a diagram illustrating an example of the configuration of a radiation image processing display device that includes a radiographic image processing display device. 10...Radiation image processing display device 11...Central processing unit (CPU) 13...Interface 14.15...Image processing unit (ALU) 30...
・Radiation image reading device 61... Stimulable phosphor sheet 69... Stimulated luminescent light 71... Photo multilayer No. 1A Figure old figure ---→-X

Claims (1)

[Claims] An original image signal Sorg in which pixel signals Sorg(i) corresponding to each pixel i (i is a positive integer) of a radiation image is arranged in time series is input, and the emphasis coefficient is β and the gradation level is Each pixel i is obtained by averaging the pixel signals within a predetermined pixel range around each pixel i, where the coefficient is γ.
When the blur mask signal corresponding to Sus(i) and the image signal after arithmetic processing corresponding to each pixel i are pixel processed signal Scal(i), the formula Scal(i)=γ{Sorg(i)+β (Sorg(
i)-Sus(i))} for each pixel i to obtain an arithmetic processed image signal Scal in which the pixel processed signals Scal(i) are arranged, the original image signal A buffer for temporarily storing Sorg, and a plurality of blur mask signals Sus_1(i), Sus_2( with different predetermined pixel ranges for each pixel i).
i),..., a blur mask calculation processor for calculating Susn(i) (n is an integer of 2 or more), and the plurality of blur mask signals Sus_1(i), Sus_2(i),...
The arithmetic processing is performed using each of the arithmetic processing image signals Scal_1 and Scal_
2, .
(i), ..., Susn(i), when the final pixel signal from which all of Susn(i) can be obtained is input to the buffer, the plurality of blur mask signals Sus_1(i) corresponding to each pixel i , Sus_2(i),...
A radiation image processing apparatus characterized in that it obtains Susn(i).