WO2023128019A1

WO2023128019A1 - X-ray sensing device capable of acquiring dual-energy image through one-time photography, and image processing method

Info

Publication number: WO2023128019A1
Application number: PCT/KR2021/020281
Authority: WO
Inventors: 박원기; 이성철; 전병찬; 서연호
Original assignee: 한국전자기술연구원
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2023-07-06
Also published as: KR20230102142A

Abstract

Provided are: an X-ray sensing device comprising a scintillator, a color filter, and a CMOS image sensor; and a method for processing an image acquired using same. The X-ray sensing device according to an embodiment of the present invention comprises: a dual-layer scintillator provided as a two-layer scintillator in order to convert energy spectra of different bands into visible light of different colors; a color filter arranged at the rear end of the dual-layer scintillator; and a CMOS image sensor arranged at the rear end of the color filter so as to acquire and process an image having passed through the dual-layer scintillator and the color filter. Therefore, a dual-energy image including X-ray energy of different bands is acquired through one-time photography and is processed as an image, and thus the amount of information that can be obtained through an X-ray image can be increased.

Description

X-ray sensing device and image processing method enabling dual energy image acquisition with one shot

The present invention relates to an X-ray sensing device and an image processing method using the same, and more particularly, to an X-ray sensing device composed of a scintillator, a color filter, and a CMOS image sensor, and a method for processing an image obtained using the same. it's about

In order to obtain an X-ray image with anatomical information of the human body as a normal X-ray image and an attenuated X-ray image by taking a picture of the human body once, two detectors were used as in Korean Patent Registration No. 10-1980533. and an attenuation filter were used.

In the case of Korean Patent Registration No. 10-1980533, the filter consists of a grid pattern or vertical stripe type attenuation part and a transmission part, but the difference in information between the respective images obtained through the attenuation part and the transmission part is not large, so the image enhancement effect may be limited. there is.

In addition, since the attenuation coefficient of a material is different according to the X-ray energy, the existing dual energy subtraction image processing method targets two types of images obtained based on different bands of X-ray energy. Image information of a specific material (ex. bone, tissue, etc.) may be highlighted by performing a subtraction operation.

However, since this conventional dual energy subtraction image processing method applies the same coefficient to all pixels of an image and proceeds with the calculation, the difference in information for each pixel is different, but it is inevitable to apply the coefficient of the average value, resulting in an image enhancement effect. may be limited.

The present invention has been devised to solve the above problems, and an object of the present invention is to acquire dual energy images including X-ray energies of different bands in one shot and process them to obtain X-ray images. An object of the present invention is to provide an X-ray sensing device capable of increasing the amount of information obtainable through a ray image and an image processing method using the same.

According to an embodiment of the present invention for achieving the above object, an X-ray sensing device is a dual layer scintillator provided with two layers of scintillators to convert energy spectra of different bands into visible light of different colors. Reiter; a color filter disposed behind the dual layer scintillator; and a CMOS image sensor disposed at a rear end of the color filter to obtain and process an image passing through the dual layer scintillator and color filter.

The dual-layer scintillator may include a first scintillator that converts an energy spectrum of a low band in the X-Ray spectrum into visible light of a specific color; and a second scintillator for converting an energy spectrum of a high band among the X-ray spectrum into visible light of a different color that does not overlap with visible light of a specific color converted by the first scintillator.

In addition, the color filter includes a first filter through which first visible light converted into a high-band energy spectrum passes and a second filter through which second visible light converted into a low-band energy spectrum passes. , The first filter and the second filter may be arranged in a lattice pattern such that the number of pixels of the first visible light and the second visible light input to the CMOS image sensor is the same.

In addition, the CMOS image sensor separates and acquires a first image obtained by converting a high-band energy spectrum and a second image obtained by converting a low-band energy spectrum from data passing through a color filter, and selects various regions of interest in each image. (Region of Interest) can be separated, and a Dual Energy Subtraction algorithm can be applied to each region of interest.

Also, the CMOS image sensor may acquire the first image and the second image by performing a bilinear interpolation operation.

The CMOS image sensor may separate a first ROI corresponding to a bone and a second ROI corresponding to a tissue from the first and second images, respectively.

In addition, the CMOS image sensor acquires an image I defined in Equation 1 below by applying a dual energy subtraction algorithm using a different coefficient for each region of interest, and in the case of the first region of interest, a tissue corresponding to To remove the image, the coefficient of tissue thickness (xt)

Become 0, and in the case of the second region of interest, in order to remove the image corresponding to the bone, the coefficient of the bone thickness (xb)

can be set to 0.

(Equation 1)

Meanwhile, an image processing method according to another embodiment of the present invention includes a dual layer scintillator provided with two layers of scintillators to convert energy spectra of different bands into visible light of different colors, and a dual layer scintillator of the dual layer scintillator. An X-ray sensing device including a color filter disposed at the rear and a CMOS image sensor disposed at the rear of the color filter to acquire and process an image passing through the dual-layer scintillator and the color filter, separating and acquiring a first image obtained by converting a high-band energy spectrum and a second image obtained by converting a low-band energy spectrum from data that has passed through a color filter; Separating, by an X-ray sensing device, several types of regions of interest from each image; and applying, by the X-ray sensing device, a dual energy subtraction algorithm for each region of interest.

As described above, according to the embodiments of the present invention, dual energy images including X-ray energies of different bands are obtained with one shot and image processing is performed to obtain a dual energy image obtained through an X-ray image. information can be increased.

1 is a diagram provided for explanation of an X-ray sensing device capable of acquiring a dual energy image with one shot according to an embodiment of the present invention;

2 is a diagram provided for explanation of a color filter according to an embodiment of the present invention;

3 illustrates a process of separating a first image obtained by converting a high-band energy spectrum and a second image obtained by converting a low-band energy spectrum from data acquired through a CMOS image sensor according to an embodiment of the present invention. drawings provided in

4 is a diagram provided for explanation of a process of separating various types of regions of interest through a CMOS image sensor according to an embodiment of the present invention; and

5 is a diagram provided for explanation of an image processing method capable of acquiring a dual energy image with one shot according to an embodiment of the present invention;

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 is a diagram provided for explanation of an X-ray sensing device capable of obtaining a dual energy image with one shot according to an embodiment of the present invention, and FIG. 2 is a description of a color filter according to an embodiment of the present invention. It is a drawing provided in

An X-ray sensing device capable of obtaining a dual energy image with one shot according to the present embodiment (hereinafter, collectively referred to as an 'X-ray sensing device') has different X-ray energies of different bands with one shot. It is provided to acquire a dual energy image including and image processing it.

To this end, the X-ray sensing device may include a dual layer scintillator 100, a color filter 200, and a CMOS image sensor 300.

The dual layer scintillator 100 is disposed on the rear surface of the object 20 so that X-rays transmitted from the X-ray generator 10 pass through the object 20 and are transmitted to the dual layer scintillator 100. can do.

Specifically, the dual-layer scintillator 100 is provided with two layers of scintillators, and can convert energy spectra of different bands into visible light of different colors.

That is, the dual layer scintillator 100 includes a first scintillator that converts the energy spectrum of a low band of the X-Ray spectrum into visible light of a specific color, and the energy spectrum of a high band of the X-Ray spectrum to the first scintillator. It may include a second scintillator that converts the visible light of a specific color into visible light of a different color that does not overlap with the visible light of a specific color converted by the scintillator.

Specifically, the first scintillator can convert the energy spectrum of a high band (ex: about 60 to 110 keV) of the X-Ray spectrum into visible light of a specific color that does not overlap. An energy spectrum of a low band (ex: about 10 to 60 keV) of the spectrum can be converted into visible light of a specific color.

The color filter 200 may be disposed at a rear end of the dual layer scintillator 100, and includes a first filter through which first visible light converted into a high band energy spectrum passes and a first filter through which a low band energy spectrum is converted. A second filter through which second visible light may pass may be included.

In this case, as illustrated in FIG. 2 , the first filter and the second filter may be arranged in a lattice pattern such that the number of pixels of the first visible light and the second visible light input to the CMOS image sensor are the same.

The CMOS image sensor 300 is disposed at the rear end of the color filter 200 to obtain an image that has passed through the dual layer scintillator 100 and the color filter 200 and process the image.

3 is a diagram for separating a first image obtained by converting a high-band energy spectrum from data acquired through a CMOS image sensor 300 according to an embodiment of the present invention and a second image obtained by converting a low-band energy spectrum. 4 is a diagram provided for description of a process, and FIG. 4 is a diagram provided for description of a process for separating various types of regions of interest through the CMOS image sensor 300 according to an embodiment of the present invention.

The CMOS image sensor 300 according to the present embodiment obtains image data converted into visible light of two different colors passing through the dual layer scintillator 100 and the color filter 200, and performs image processing. there is.

Specifically, the CMOS image sensor 300 may separate and acquire a first image obtained by converting a high-band energy spectrum and a second image obtained by converting a low-band energy spectrum from data passing through the color filter 200. In addition, various types of regions of interest may be separated from the obtained first image and the second image, and a dual energy subtraction algorithm may be applied to each region of interest.

For example, when the CMOS image sensor 300 acquires the first image and the second image, the high-band energy is converted to a first region of interest (High-Bone) corresponding to a bone and tissue in the first image. The corresponding second region of interest (High-Tissue) is separated, and in the second image in which the energy of the low band is converted, the first region of interest (Low-Bone) corresponding to the bone and the second region of interest (Low-Bone) corresponding to the tissue are separated. -Tissue) can be separated, and a dual energy subtraction algorithm can be applied to each region of interest.

In this case, the CMOS image sensor 300 may acquire the first image and the second image by performing a bilinear interpolation operation as illustrated in FIG. 3 .

For example, when the CMOS image sensor 300 performs a bilinear interpolation operation, in the case of the H13 pixel (High Energy pixel) of FIG. 3, the high energy of the high band is the band value of H13 and , Low energy of the low band can be calculated as (L12 + L14 + L23) / 3, and in the case of the L34 pixel (Low Energy pixel) of FIG. 3, the low energy of the band is the band of L34. value, and the high energy of the band can be calculated as (H24 + H33 + H35 + H44) / 4.

Also, the CMOS image sensor 300 may separate various types of regions of interest from the first image and the second image using a histogram separation method or an edge detection method, respectively, as illustrated in FIG. 4 . there is.

For example, the CMOS image sensor 300 determines a first region of interest corresponding to bones, a second region of interest corresponding to tissues, and a third region of interest where bones and tissues coexist, respectively, from the first and second images. can be separated

In addition, the CMOS image sensor 300 may obtain an image I defined in Equation 1 below by applying a dual energy subtraction algorithm using a different coefficient for each region of interest.

(Equation 1)

Here, when single-energy radiation is used and there is no scattering, the intensity of radiation transmitted through tissues and bones is equal to Equation 2 below in the case of the second image in which low-band energy is converted, and high-band energy is converted In the case of the first image, it is equal to Equation 3 below.

(Formula 2)

(Formula 3)

In addition, when different weighting factors are applied to each image, the obtained image is as shown in Equation 4 below.

(Formula 4)

Through this, if Equation 2 and Equation 3 are applied to Equation 4, Equation 1 can be calculated.

In this case, in the case of the first region of interest, the CMOS image sensor 300 coefficients the tissue thickness (xt) to remove an image corresponding to the tissue.

can be set to 0.

In addition, the CMOS image sensor 300, in the case of the second region of interest, in order to remove the image corresponding to the bone, the coefficient of the bone thickness (xb)

can be set to 0.

Here, each parameter is as follows.

In summary, the CMOS image sensor 300 detects a first region of interest (High-Bone) corresponding to bone and a second region of interest (High-Tissue) corresponding to tissue in the first image in which high-band energy is converted. A first region of interest (Low-Bone) corresponding to a bone and a second region of interest (Low-Tissue) corresponding to a tissue are separated from the second image in which the energy of the low band is converted, and each of the separated regions of interest is separated. A dual energy subtraction algorithm can be applied for each.

Through this, it is possible to increase the amount of information obtained through the X-Ray image compared to the conventional case of applying the same coefficient to all pixels of the image.

FIG. 5 is a diagram provided to explain an image processing method capable of acquiring a dual energy image with one shot according to an embodiment of the present invention.

An image processing method capable of obtaining a dual energy image with one shot according to the present embodiment (hereinafter, collectively referred to as an 'image processing method') includes the X-ray sensing device described above with reference to FIGS. 1 to 4. You can run it using

Referring to FIG. 5 , in this image processing method, a first image in which a high-band energy spectrum is converted from data that has passed through the dual-layer scintillator 100 and the color filter 200 using the CMOS image sensor 300 is used. The second image obtained by converting the energy spectrum of the low band and the energy spectrum of the low band may be separated and obtained (S510).

And the image processing method, when the first image and the second image are acquired, separates several types of ROI from each image (S520), and applies a dual energy subtraction algorithm to each separated ROI (S530), thereby making it easier than before. An X-Ray image with an increased amount of information can be obtained.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, and is common in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications are possible by those who have knowledge of, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

Claims

a dual-layer scintillator provided with two layers of scintillators to convert energy spectra of different bands into visible light of different colors;

a color filter disposed behind the dual layer scintillator; and

An X-ray sensing device comprising: a CMOS image sensor disposed at a rear end of the color filter to obtain and process an image passing through the dual-layer scintillator and the color filter.
The method of claim 1,

The dual layer scintillator,

a first scintillator that converts an energy spectrum of a low band in the X-Ray spectrum into visible light of a specific color; and

and a second scintillator for converting the energy spectrum of a high band among the X-ray spectrum into visible light of a different color that does not overlap with the visible light of a specific color converted by the first scintillator. .
The method of claim 2,

color filters,

A first filter through which first visible light converted into a high band energy spectrum can pass and a second filter through which second visible light converted into a low band energy spectrum can pass,

The first filter and the second filter,

An X-ray sensing device characterized in that the number of pixels of first visible light and second visible light input to a CMOS image sensor is arranged in a grid pattern.
The method of claim 3,

CMOS image sensor,

From the data that has passed through the color filter, a first image in which the energy spectrum of the high band is converted and a second image in which the energy spectrum in the low band is converted are separated and acquired, and several types of regions of interest are obtained from each image. X-ray sensing device characterized by separating and applying a dual energy subtraction algorithm for each region of interest.
The method of claim 4,

CMOS image sensor,

An X-ray sensing device characterized in that a first image and a second image are obtained by performing a bilinear interpolation operation.
The method of claim 4,

CMOS image sensor,

An X-ray sensing device that separates a first region of interest corresponding to a bone and a second region of interest corresponding to a tissue from the first image and the second image, respectively.
The method of claim 4,

CMOS image sensor,

An image (I) defined in Equation 1 is obtained by applying a dual energy subtraction algorithm using a different coefficient for each region of interest,

In the case of the first region of interest, in order to remove an image corresponding to the tissue, the coefficient of tissue thickness (xt)
be 0,

In the case of the second region of interest, in order to remove the image corresponding to the bone, the coefficient of the bone thickness (xb)
X-ray sensing device, characterized in that so that is zero.

(Formula 1)
A dual-layer scintillator provided with two layers of scintillators to convert energy spectrums of different bands into visible light of different colors, a color filter disposed after the dual-layer scintillator, and a color filter disposed after the color filter, An X-ray sensing device including a CMOS image sensor that acquires and processes an image that has passed through a layer scintillator and a color filter converts high-band energy spectrum from data that has passed through a dual-layer scintillator and color filter. separating and acquiring a first image and a second image obtained by converting a low-band energy spectrum;

Separating, by an X-ray sensing device, several types of regions of interest from each image; and

An image processing method comprising: applying, by an X-ray sensing device, a dual energy subtraction algorithm for each region of interest.