JPS6289177A - Non-sharp mask signal calculating method and its device - Google Patents

Abstract

PURPOSE:To shorten a calculating time and to rapidly and successively calculate Sus by obtaining and storing a basic non-sharp mask signal Sus of a mask size NXM on respective scanning points and simply adding the basic non-sharp mask signals of alpha1Xalpha2 included in the mask of alpha1NXalpha2M size to obtain an average value. CONSTITUTION:The calculation of a different Sus means the calculation of the Sus based on the non-shapr mask of a different size, and the Sus of alpha1NXalpha2M size is successively calculated, making a basic non-sharp mask signal Sus in a basic non-sharp mask of NXM size a base. The masks are all square in shape and a mask size 3X3 is stored in a memory 202. The Sus of the mask size 9X9 is obtained by simply adding nine Sus on respective masks MA-MI of the mask size 3X3 in the second arithmetic unit 203 to obtain a mean value. The non-sharp mask processing picture based on the respective Sus is alternately stored in the first frame memory 410 and the second frame memory 402 and alternately displayed on a CRT 46 as a visual picture on a D/A converter 44.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a method for calculating a non-sharp mask signal used when performing non-sharp mask processing on an image signal, and an apparatus for implementing the method.

(Technical background of the invention and prior art) Certain phosphors emit radiation 41 (X-rays, α-rays, β-rays).

When the phosphor is irradiated with γ-rays, 'R-rays, ultraviolet rays, etc., part of the energy of this radiation is accumulated in the phosphor, and when the phosphor is then irradiated with excitation light such as visible light, the accumulated energy is The phosphor exhibits stimulated luminescence depending on the A phosphor exhibiting such properties is called a stimulable phosphor (III-exhaustive phosphor).

Using this stimulable phosphor, radiation image information of a subject such as a human body is recorded on a stimulable phosphor sheet (hereinafter referred to as a stimulable phosphor sheet), and the sheet is scanned with excitation light. A radiographic image information recording and reproducing system has been proposed that generates stimulated luminescence, photoelectrically reads the stimulated luminescent light to obtain an image signal, and processes this image signal to obtain a radiographic image of a subject that is suitable for diagnosis ( For example, JP-A-55-124
No. 29.

No. 55-116340, No. 55-163472, No. 56-11395.

513-104ff No. 45, etc.).

According to this system, radiation image information stored and recorded on a stimulable phosphor sheet is photoelectrically read, the electrical signal is subjected to appropriate signal processing, and this electrical signal is used to produce recording materials such as photographic materials. Can radiation images be displayed on display devices such as CRT? ! By outputting the images as four images, a very large effect can be obtained in that a radiation image having excellent suitability for observation and interpretation (diagnosis suitability) can be obtained.

One such signal processing method is, for example, Japanese Unexamined Patent Publication No. 55-1
There is a non-sharp mask processing method as described in Japanese Patent No. 63472.

Briefly, this method photoelectrically reads the radiation image information stored and recorded on the stimulable phosphor sheet by scanning the excitation light, and the original image signal (
At the same time as obtaining the electric signal) Sorg, a non-sharp mask signal Sus corresponding to the ultra-low spatial frequency at each scanning point of the stimulable phosphor sheet is obtained, and the emphasis coefficient is set to β, and for Sorg at each scanning point above, Then, the signal is converted by the calculation S'-Sorg+β(Sora-8LIS) to emphasize the frequency component (frequency band) above the ultra-low spatial frequency, and this signal S' is used for forming the visible image. It is characterized by the following.

This non-sharp mask processing method is extremely useful in that it increases the contrast of the diagnostic target (pulmonary blood vessels, epiphyses, malignant tumors, soft tissues, etc.), increases the efficiency of interpretation and diagnosis, and reduces the rate of missed lesions. This is an image processing method.

However, the optimum values of the emphasis frequency band and the emphasis coefficient in this unsharp mask processing vary within the same image depending on the diagnostic purpose of the doctor. For example, if we take a fracture in a limb as an example, first of all, in order to properly diagnose the fracture line, etc., it is desirable to emphasize a relatively high frequency band to clearly depict the outline of the bone. In order to diagnose soft tissue inflammation, it is desirable to emphasize relatively low frequency bands.

In other words, when interpreting and diagnosing images, multiple de-sharpening and masking processes are applied to a single image under different conditions (different emphasis frequency bands and different emphasis coefficients), and the process is performed based on these multiple processed images. There may be cases where you want to perform a diagnosis.

One of the unsharp mask processing image display methods suitable for such cases is to sequentially change the unsharp mask signal Sus, perform unsharp mask processing based on each of the changed Sus, and display each unsharp mask signal Sus. The mask-processed images are displayed one after another on a display device such as a CRT.

In other words, a method has been considered in which an image is displayed on a display device as a moving image that changes from moment to moment, and the image change can be stopped arbitrarily.

According to this method, a large number of unsharp mask-processed images with different emphasis frequency bands are continuously displayed on a display device as moving images, allowing doctors to obtain information necessary for various diagnostic purposes. Optimized images can be obtained and observed without exception in a short time, making it possible to dramatically improve diagnostic performance and streamline diagnostic work (time reduction).

However, in order to implement the above method, it is necessary to quickly perform unsharp mask processing calculations based on each changed Sus, and for this purpose, it is necessary to quickly sequentially process the plurality of unsharp mask signals Sus as described above. need to ask.

(Object of the Invention) In view of the above-mentioned circumstances, an object of the present invention is to provide a system that is particularly suitable for use when sequentially changing the unsharp mask signal Sus as described above and continuously performing unsharp mask processing based on each Sus. An object of the present invention is to provide an unsharp mask signal calculation method that can quickly calculate different unsharp mask signals Sus, and an apparatus for implementing the method.

(Structure of the Invention) In order to achieve the above object, the method according to the present invention is a method of sequentially calculating different unsharp mask signals Sus, and has a mask size N×M (N and M are the number of scanning points, 1
When a predetermined scanning point is located at the center of a rectangular basic unsharp mask (an integer excluding A basic unsharp mask signal Sus is calculated, this basic unsharp mask signal Sus is calculated for each scanning point, and the result (SO8) is stored, and subsequent calculations of different 5IJS at the above predetermined scanning points are , α! included in the unsharp mask of mask size α1N×αz M (αl and α2 are integers excluding 1). The stored basic unsharp mask values @Sus for ×α2 basic unsharp masks are calculated by simple averaging, and the calculation of Sus by this method is performed using different α1.
It is characterized by multiple kisses below the α2 value.

Further, in order to achieve the above object, the apparatus according to the present invention has a mask size N×M (NSM is the number of scanning points, and 1
When a predetermined scanning point is located at the center of a rectangular basic unsharp mask of (an arbitrary integer other than Basic unsharp mask signal S at the point
A first ** unit that calculates us, a memory that stores the unsharp mask signal Sus for each scanning point calculated by the arithmetic unit, and a mask size α1N×α2 M (an integer excluding α1.α2c1). The basic unsharp mask signals 9uS for the α1×α2 basic unsharp masks in the unsharp mask are read from the memory, and by simply averaging them, a different unsharp mask signal Sus at the predetermined scanning point is obtained. α1. While changing α2 sequentially, each α1. Non-sharp mask belief in α2 @
The present invention is characterized by comprising a control device that outputs a command to obtain Sus.

(Effects of the Invention) As described above, the unsharp mask signal Sus calculation method and device according to the present invention provide basic unsharp mask signals of basic unsharp mask size N×M (N and M are arbitrary integers except 1). Obtaining a sharp mask signal Sus for each scanning point, and storing each basic unsharp mask signal Sus,
From now on, the mask size α1N×α2 M (α1, α2 bi1
A variable consisting of integers excluding , for example 2.3, 4.5
．． 6,7°8.9. .
It is obtained by simply averaging s.

Therefore, when calculating using only the conventional 3 org,
α! In order to calculate the signal Sus for a mask of NXα2M size, it is necessary to add αlNXα2M Sorgs and divide by α1N×α2M, and in the end, αlα2M
It was necessary to perform N+1 calculations, but according to the present invention, all that is required is to add α1×α2 basic unsharp mask signals 5us and divide by α1N×α2M, resulting in α! α2
Since only +1 calculation is required, the calculation time is shortened, and as a result, the effect that the specific Sus can be calculated sequentially and quickly is achieved.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The unsharp mask signal calculation method and device according to the present invention include:
The recording medium is scanned to obtain an original image signal 3 org for each scanning point, and each original image signal 3 or
For g, S'-3oro+β(Sorg-8ue) However, S
us: Unsharp mask signal corresponding to ultra-low spatial frequency at each scanning point β: Calculate an emphasis coefficient to perform unsharp mask processing, and perform the unsharp mask processing continuously based on sequentially different signals 5 us Since this is used when the process is performed multiple times, this point will be explained first.

The recording medium may be, for example, the stimulable phosphor sheet or an X-ray photographic film.

In the case of a stimulable phosphor sheet, Sorg scans a stimulable phosphor sheet onto which radiation has passed through the subject with excitation light such as a laser beam, and stimulates the stimulated luminescence light emitted from the sheet by this scanning. is determined by photoelectrically reading it with a photoelectric reading means such as a photomultiplier.

In the case of an X-ray photographic film, Sorg is determined, for example, by optically scanning the X-ray photographic film on which an image has been developed and photoelectrically reading the light transmitted through or reflected by the film.

The unsharp mask signal Sus is obtained by preparing a rectangular unsharp mask of an arbitrary size, and the size of the mask (the mask size is expressed by the length of two adjacent sides of the mask, and the length of each side is the length of the scanning point. 3 or
A method is used in which Sus regarding the predetermined scanning point is determined by reading g and Sorg of scanning points around the scanning point from the memory and simply averaging them. In other words,
When determining the Sus of a predetermined scanning point, prepare a rectangular unsharp mask of a predetermined size, and when the predetermined scanning point is located in the center of the mask, simply add the SOrg of all the scanning points located within the mask. It is determined by averaging.

The above unsharp mask processing is performed as follows: - each scanning point in the image is s' = sorg + β (Sorg - 8US)
In order to perform such unsharp mask processing multiple times consecutively based on different signals Sus, it is necessary to calculate different signals Sus extremely quickly for each scanning point. .

If the calculation speed of the signal Sus is slow, the unsharp mask processing speed will also be slow, and as a result, for example, when trying to display a large number of processed images continuously as if they were moving images, it is difficult to display such moving images. This is because it becomes

Different Sus means that the unsharp mask sizes used when calculating Sus are different. Therefore, sequentially calculating different Sus at predetermined scanning points means sequentially changing the mask size at an appropriate step size and within an appropriate range, and calculating Sus for each non-sharp mask of each size. .

Next, we will discuss the method and apparatus according to the present invention used when performing image processing as described above, that is, different Sus
An embodiment of a method and apparatus for determining .

FIG. 1 is a block diagram showing an example of an image display device including an embodiment of the device according to the present invention.

The illustrated device not only generates the unsharp mask signal Sus, but also
An image display device configured to perform unsharp mask processing multiple times while sequentially changing the emphasis signal β as necessary, and to continuously switch and display the unsharp mask processed images, An original image signal memory 10 that stores the original image signal Sorg for each scanning point obtained by scanning a recording medium, and a non-sharp mask processing that performs non-sharp mask processing on this original image signal 3 or! The unsharp mask processing device 20 is operated to sequentially change at least one of the 5us and β, and perform the unsharp mask processing under each changed Sus or β value. death .

υJtlD device ff30 and each of the above Sus or each β
The CRT device 40 continuously displays a plurality of processed images based on the image signal S' obtained by performing unsharp mask processing under the values of .

The control device 30 has various control information, such as mode (Su
whether to change either s or β), the parameter (Su
It is necessary to input the change range of s or β), the step size of the change, the start or stop of the motion, etc. Although these control information may be input directly to the control device 30 via a human or a host computer, this device is equipped with a control information input device 50, and the input device 50 inputs the various control information described above from a human or a host computer. It is configured to receive the signal, convert the control information into an appropriate signal, and output the signal to the control device 30.

The CRT @ 40 has a first frame memory 401 and a second frame memory 401 that store the processed image signal S' subjected to the unsharp mask processing in the unsharp mask processing device 20 one by one.
Frame memory 402 and the frame memory 401
．． D/A converts the signal output from 402
It comprises a converter 44 and a CRT 4B that outputs and displays a visible image based on the signal output from the D/A converter.

The unsharp mask processing device 20 has a mask size N×M at each scanning point (N and M are integers excluding 1, preferably N
is an odd number and N-3) A first computing unit 201 that computes the basic unsharp mask signal Sus for the basic unsharp mask
and a memory for storing each basic unsharp mask signal Sus.
202, and a second computing unit 2 which calculates non-sharp mask signals Sus of different mask sizes by suitably adding and averaging the respective non-sharp mask signals Sus according to a command from the control device 30.
03, a subtracter 204 that performs the operation Sorg-8LIS between Sus obtained in this way and the original image signal Sorg, and β to the output from the subtracter 204.
and an adder 206 that adds Sorg to the output from the multiplier 205 and performs the operation Sorg + β (Sora-Sus). .

The first arithmetic unit 201, the memory 202, the second arithmetic unit 203, and the control t11 device 30 provide
An embodiment of a computing device is configured.

In this embodiment, mask size 3 is used as the basic non-sharp mask.
A square mask of x3 is set, and the basic unsharp mask signal Sus for each scanning point is calculated by the first arithmetic unit 20 using this mask.
Calculated by 1.

FIG. 2 is a diagram showing a stimulable phosphor sheet 60 which is a recording medium, and each square in the diagram represents one scanning point. For example, the basic unsharp mask signal Sus to a predetermined scanning point in FIG. It is obtained by simply averaging 9 org of a total of 9 scanning points included in the . The Sorg of each scanning point is read from the original image signal memory 10 and used. In this way, the basic unsharp mask signal 5IJS at each scanning point becomes the first ? ! t
Each calculated Sus is calculated by the iR unit 201 and stored in the memory 202, and the subtracter 2 uses the Sus.
At 04, an operation called Sorg-Sus is performed (the second arithmetic unit 203 is used to calculate the subsequent Sus), and the CR
An image subjected to unsharp mask processing based on the basic unsharp mask signal Sus is output onto the T device 40.

Next, the case of calculating different Sus at the predetermined scanning point A will be explained. Calculating different Sus means calculating Sus based on unsharp masks of different sizes, and the present invention calculates Sus based on the basic unsharp mask signal Sus with the basic unsharp mask of N×M size. , α1N×α2M (α1 and α2 are variables consisting of integers excluding 1) are used to sequentially calculate the unsharp mask signal Sus using the unsharp mask.

In this embodiment, all masks are assumed to be square, and (α
1-α2) Based on the above basic 3×3 mask size, 9×9, 15×15.21×21°27
x27.・・・・・・・・・, 111X 111
and 191I in odd increments of 3, and Sus at each mask size is calculated. The mask size 3x3 is stored in the memory 202 as described above, and 5IJS of mask size 9x9 stores nine Sus of mask size 3x3 as the mask for scanning point A in FIG. When finding Sus of size 9X9,
It is obtained by simply averaging a total of nine Sus for each mask M^ to MK with a mask size of 3×3 using the second arithmetic unit 203. Mask size 15x15.2
1x21. Similarly, when calculating each Sus of . . . , 25, 49, . . .
- Obtained by simple addition and averaging.

The unsharp mask processed image based on each Sus obtained in this way is stored in the first frame memory 401 and the second frame memory 401.
The data is alternately stored in the frame memory 402, and from both frame memories is alternately transmitted to the CRT4 via the D/A'a converter 44.
It is displayed as a visible image on G. For example, mask size 3
The processed image based on ×3 Sus is stored in the first frame memory.
While the image is stored in the second frame memory 401 and displayed on the CRT4B, the next processed image signal based on Sus with a mask size of 9x9 is written to the second frame memory 402, and when the processing is completed, this second frame memory 4
02 is connected to the O/A'l switch 44, the images displayed on the CRT 46 are switched, and this switching is performed one after another in a short period of time, and the images are displayed as if they were moving images.

Sus of different mask sizes in the second*l device 203
Calculations are performed based on commands from control device 30.

A specific example of the role of the control device 30 will be explained below.

First, in the case of Sus change, Su
The receiver receives the information that there is a change in s and controls the mode. In this case, since it is a Sus change, β is fixed. Next, based on the conditions given to the control information input device 50 (for example, in what step size and within what range Sus should be changed), the required number of processing repetitions and the mask size for each process (for example, 3×3 .9X9, 21X21
．． ......57X57) etc. Next, upon receiving a motion start signal from the control information input device 50, the entire apparatus is started through the synchronization line. When the calculation and image display using the first mask size of R are completed, the next mask size is applied to the necessary parts of the entire device, and the next calculation and image display are started. When this process is repeated a predetermined number of times or when a motion stop signal is received from the control information input device 50, the process is stopped and the current CR
Stops when T is displayed.

In the case of β change, there is no need for complicated calculations as in the case of Sus change, and the control device 30 simply uses the multiplier 205 based on information such as the change width received from the control information input device 50.
It is sufficient to simply change the multiplier β in .

In the above embodiment, N=3, but as long as N is an integer other than 1, it may be a number other than 3, such as 2 or 5. When N and M are 1, when changing α1°α2 to obtain different Sus, the original image signal 3 o
It is excluded because it is equivalent to calculating using rg, and the speed-up of calculation, which is an effect of the present invention, cannot be achieved.

In addition, in the above embodiment, α1=α2 and αl and α
2 was changed in order as 3, 5, 7, 9, etc., but this α1. α2 may also be an integer other than 1,
The change may be made in any manner. For example, 3
．． 7.11.15...river...may be changed sequentially with every other odd number. α! And when α2 is 1, it has the same size as the basic non-sharp mask and is excluded. Of course, the maximum and minimum values of α1 and CX2 can be set arbitrarily.

In the present invention, since Sus is calculated as described above, for example, S for a mask of size α1N×α2M
When calculating us@, it is sufficient to add α1×α2 basic sharpening mask signals Sus and divide by α1N×α2M,
A total of α1α2+1 calculations is required, and different Sus can be calculated sequentially and quickly.

Furthermore, in the calculation of Sus in the present invention, the step width of change in Sus (width of change in mask size) is limited to some extent.
For example, in the embodiment described above, calculations can only be made for masks of odd number multiples of 3×3, but for example, unsharp mask processing is performed by sequentially changing the sus described above,
Each processed image is continuously switched and displayed as a moving image on a CRT.
When performing a medical diagnosis using the moving image displayed on the screen, a step width of this level will not cause any practical problems and can be used in practice.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of an image display arrangement including an embodiment of the unsharp mask signal calculation device according to the present invention, and FIG. 2 is a diagram showing a recording medium and scanning points thereon. 10...Original image signal memory 30...Control device 40...CRT device 60...Recording medium 201...First computing unit 202...Memory

Claims (2)

[Claims] (1) Scan the recording medium to obtain the original image signal Sorg for each scanning point, and each original image signal So
For rg, S' = Sorg + β (Sorg - Sus) where Sus: unsharp mask signal corresponding to extremely low spatial frequency at each scanning point β: unsharp mask processing is performed by performing an operation called an emphasis coefficient At the same time, the unsharp mask processing is sequentially performed using different unsharp mask signals Sus.
A method of calculating the above-mentioned different unsharp mask signals Sus to be used when performing multiple consecutive operations based on the mask size N×M (N and M are the number of scanning points, and are arbitrary integers except 1). A rectangular basic unsharp mask is set, and when a predetermined scanning point is located in the center of this basic unsharp mask, the original image signals Sorg of all the scanning points included in this mask are simply added and averaged to obtain the above. A basic unsharp mask signal Sus at a predetermined scanning point is calculated, the above basic unsharp mask signal Sus is calculated for each scanning point, and each calculated basic unsharp mask signal Sus is calculated.
is stored, and a different unsharp mask signal Su at the above-mentioned predetermined scanning point is stored.
The calculation of s is based on the mask size α_1N×α_2M (α_1
, α_1× in the unsharp mask (α_2 is an integer excluding 1)
This is performed by simply averaging the stored basic unsharp mask signals Sus for α_2 basic unsharp masks, and the calculation of the unsharp mask signal Sus by this method is performed under different α_1 and α_2 values. A non-sharp mask signal calculation method characterized by performing the calculation multiple times. (2) Scan the recording medium to obtain the original image signal Sorg for each scanning point, and each original image signal So
For rg, S' = Sorg + β (Sorg - Sus) where Sus: unsharp mask signal corresponding to extremely low spatial frequency at each scanning point β: performs unsharp mask processing by performing an operation called an emphasis coefficient, and , the unsharp mask processing is sequentially performed using different unsharp mask signals Sus
A device for calculating the above-mentioned different unsharp mask signals Sus to be used when carrying out a plurality of continuous operations based on the mask size N×M (N and M are the number of scanning points and are arbitrary integers except 1). When a predetermined scanning point is located at the center of a rectangular basic unsharp mask, the basic unsharp mask at the above predetermined scanning point is obtained by simply averaging the original image signals Sorg of all the scanning points included in this mask. Signal Sus
a first arithmetic unit that calculates , a memory that stores the unsharp mask signal Sus for each scanning point calculated by the first arithmetic unit, and a mask size α_1N×α_2M (α_1 and α_2 are integers excluding 1); Retrieve the basic unsharp mask signals Sus for the α_1×α_2 basic unsharp masks in the unsharp mask from the memory, and simply add and average them to obtain a different unsharp mask signal Sus at the predetermined scanning point. comprising a second arithmetic unit; and a control device that outputs a command to the second arithmetic unit to sequentially change α_1 and α_2 and obtain unsharp mask signals Sus at each α_1 and α_2. A non-sharp mask signal calculation device characterized by: