CN114494028B - Particle beam imaging noise reduction method and device - Google Patents

Abstract

The embodiment of the disclosure discloses a particle beam imaging noise reduction method and a particle beam imaging noise reduction device. The particle beam imaging noise reduction method comprises the following steps: performing line scanning on the imaging area by using the particle beam to acquire a line scanning image signal; acquiring a first image signal of the line from the line scanning image signal within the effective time of the line scanning; acquiring a noise signal of the line from the line scanning image signal in the non-effective time of the line scanning; acquiring an average noise signal of the row according to the noise signal of the row; and acquiring a second image signal of the line according to the first image signal of the line and the average noise signal of the line, thereby carrying out line-by-line estimation and elimination on the noise of the imaging area, having accurate noise estimation, being capable of well tracking the change of the noise at different positions and different times and effectively improving the imaging quality.

Description

Particle beam imaging noise reduction method and device

technical field

The present disclosure relates to the technical field of image processing, in particular to a particle beam imaging noise reduction method and device.

Background technique

Particle beam imaging is widely used in various detection and imaging fields. For example, scanning electron microscopes are currently widely used in various fields such as medicine, materials, biology, and electronics. The imaging quality is the main manifestation of its performance, and reducing the noise in the imaging process is the key to improving its imaging quality. In the existing scanning electron microscope system, the noise value of all pixels in the image can be obtained by continuously obtaining two scanning electron microscope images of the sample and performing subtraction on the two images. The noise value of all pixels in the image is statistically analyzed to obtain the variance of the noise value, which is used as a characteristic parameter to describe the image noise.

The existing electron microscope noise reduction method adopts the overall processing of the image, uniform noise reduction, and adopts the same processing method for all lines, which cannot differentiate the different noise characteristics between different lines, and the time-varying tracking of noise The ability is also poor.

Contents of the invention

In order to solve problems in related technologies, embodiments of the present disclosure provide a method and device for reducing noise in particle beam imaging.

In the first aspect, an embodiment of the present disclosure provides a particle beam imaging noise reduction method, including: using a particle beam to perform line scanning on the imaging area to obtain line scanning image signals;

acquiring the first image signal of the row from the row-scanning image signal within the effective time of the row-scanning;

Acquiring noise signals of the row from the row-scanning image signal during the non-effective time of the row-scanning;

Obtaining the average noise signal of the row according to the noise signal of the row;

According to the first image signal of the row and the average noise signal of the row, the second image signal of the row is acquired.

With reference to the first aspect, in the first implementation manner of the first aspect of the present disclosure, the effective time of the row scanning includes:

The time at which the particle beam enters the sample region during the forward period of the line scan; and/or

The inactive time of the line scan includes:

the time before the particle beam enters the sample region during the forward period of the line scan; and/or

The time the particle beam is in the reverse period of the line scan.

With reference to the first aspect, in the second implementation manner of the first aspect of the present disclosure, during the non-effective time of the line scanning, obtaining the noise signal of the line from the line scanning image signal includes:

During the non-effective time of the line scanning, the particle beam is reduced, and the noise signal of the line is obtained from the line scanning image signal; and/or

During the non-effective time of the line scanning, the particle beam is deflected, and the noise signal of the line is obtained from the line scanning image signal.

With reference to the second implementation manner of the first aspect, in the third implementation manner of the first aspect of the present disclosure, the reducing the particle beam includes:

absorbing the particle beam on its way into the imaging region so that the particle beam cannot reach the imaging region; and/or

reflecting the particle beam on its way into the imaging region so that the particle beam cannot reach the imaging region; and/or

scattering the particle beam on its way into the imaging region so that the particle beam cannot reach the imaging region.

With reference to the second implementation manner of the first aspect, in the fourth implementation manner of the first aspect of the present disclosure, the deflecting the particle beam includes:

Using an electric field and/or a magnetic field to deflect the particle beam on the path where the particle beam enters the imaging region, so that the particle beam cannot reach the imaging region.

With reference to the first aspect, in the fifth implementation manner of the first aspect of the present disclosure, the obtaining the average noise signal of the row according to the noise signal of the row includes:

Integrate the noise signal of the row to obtain the average noise signal of the row; or

Perform mean filtering processing on the noise signal of the row to obtain the average noise signal of the row.

With reference to the first aspect, in the sixth implementation manner of the first aspect of the present disclosure, the acquiring the second image signal of the row according to the first image signal of the row and the average noise signal of the row includes:

performing a hold operation on the first image signal of the row to obtain a third image signal of the row;

The average noise signal of the row is subtracted from the third image signal of the row to obtain the second image signal of the row.

With reference to the sixth implementation manner of the first aspect, in the seventh implementation manner of the first aspect of the present disclosure, the subtracting the average noise signal of the row from the third image signal of the row includes:

Using a Kalman filter process, the row's average noise signal is subtracted from the row's third image signal.

With reference to the first aspect, in an eighth implementation manner of the first aspect of the present disclosure, before acquiring the first image signal of the row from the row-scanning image signal within the effective time of the row-scanning, further includes :

The line scanning image signal is converted from an analog signal to a digital signal.

With reference to the first aspect, the ninth implementation manner of the first aspect of the present disclosure further includes:

converting the second image signal from an analog signal to a digital signal.

In the second aspect, an embodiment of the present disclosure provides a particle beam imaging noise reduction device, including:

The line scanning image signal acquisition module is configured to use the particle beam to perform line scanning on the imaging area to obtain line scanning image signals;

The first image signal acquisition module is configured to acquire the first image signal of the row from the row scan image signal within the effective time of the row scan;

A noise signal acquisition module configured to acquire noise signals of the row from the row-scanning image signal during the non-effective time of the row-scanning;

an average noise signal acquisition module configured to acquire the average noise signal of the row according to the noise signal of the row;

The second image signal acquisition module is configured to acquire the second image signal of the row according to the first image signal of the row and the average noise signal of the row.

With reference to the second aspect, in the first implementation manner of the second aspect of the present disclosure, the effective time of the row scanning includes:

The time at which the particle beam enters the sample region during the forward period of the line scan; and/or

The inactive time of the line scan includes:

the time before the particle beam enters the sample region during the forward period of the line scan; and/or

The time the particle beam is in the reverse period of the line scan.

With reference to the second aspect, in the second implementation manner of the second aspect of the present disclosure, the noise signal acquisition module includes:

The particle beam reduction sub-module is configured to reduce the particle beam during the non-effective time of the line scanning, and obtain the noise signal of the line from the line scanning image signal; and/or

The particle beam deflecting sub-module is configured to deflect the particle beam during the non-effective time of the line scanning, and acquire the noise signal of the line from the line scanning image signal.

With reference to the second implementation manner of the second aspect, in the third implementation manner of the second aspect of the present disclosure, the reducing the particle beam includes:

absorbing the particle beam on its way into the imaging region so that the particle beam cannot reach the imaging region; and/or

reflecting the particle beam on its way into the imaging region so that the particle beam cannot reach the imaging region; and/or

scattering the particle beam on its way into the imaging region so that the particle beam cannot reach the imaging region.

With reference to the second implementation manner of the second aspect, in a fourth implementation manner of the second aspect of the present disclosure, the deflecting the particle beam includes:

Using an electric field and/or a magnetic field to deflect the particle beam on the path where the particle beam enters the imaging region, so that the particle beam cannot reach the imaging region.

With reference to the second aspect, in the fifth implementation manner of the second aspect of the present disclosure, the average noise signal acquisition module includes:

An integral processing submodule configured to perform integral processing on the noise signal of the row to obtain the average noise signal of the row; or

The mean value filter processing sub-module is configured to perform mean value filter processing on the noise signal of the row to obtain the average noise signal of the row.

With reference to the second aspect, in a sixth implementation manner of the second aspect of the present disclosure, the second image signal acquisition module includes:

The third image signal acquisition submodule is configured to perform a hold operation on the first image signal of the row to obtain a third image signal of the row;

The average noise signal reduction sub-module is configured to subtract the average noise signal of the row from the third image signal of the row to obtain the second image signal of the row.

With reference to the sixth implementation manner of the second aspect, in the seventh implementation manner of the second aspect of the present disclosure, the subtracting the average noise signal of the row from the third image signal of the row includes:

Using a Kalman filter process, the row's average noise signal is subtracted from the row's third image signal.

With reference to the second aspect, in an eighth implementation manner of the second aspect of the present disclosure, before acquiring the first image signal of the row from the row-scanning image signal within the effective time of the row-scanning, further includes :

The first analog-to-digital conversion module is configured to convert the line scan image signal from an analog signal to a digital signal.

With reference to the second aspect, the ninth implementation manner of the second aspect of the present disclosure further includes:

The second analog-to-digital conversion module is configured to convert the second image signal from an analog signal to a digital signal.

The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

According to the technical solution provided by the embodiments of the present disclosure, a line scanning image signal is obtained by using a particle beam to perform line scanning on the imaging area; The first image signal; during the non-effective time of the line scanning, obtain the noise signal of the line from the image signal of the line scanning; according to the noise signal of the line, obtain the average noise signal of the line; according to The first image signal of the row and the average noise signal of the row are obtained to obtain the second image signal of the row, so that the noise in the imaging area is estimated and eliminated row by row, the noise estimation is accurate, and the noise can be well tracked in different Changes in position and time can effectively improve the imaging quality.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure.

Description of drawings

Other features, objects and advantages of the present disclosure will become more apparent through the following detailed description of non-limiting embodiments in conjunction with the accompanying drawings. In the attached picture:

Fig. 1a shows an exemplary schematic diagram of an implementation scenario of a particle beam imaging noise reduction method according to an embodiment of the present disclosure;

Fig. 1b shows an exemplary schematic diagram of an implementation scenario of a particle beam imaging noise reduction method according to an embodiment of the present disclosure;

Fig. 1c shows an exemplary schematic diagram of an implementation scenario of a particle beam imaging noise reduction method according to an embodiment of the present disclosure;

FIG. 2 shows a flowchart of a method for noise reduction in particle beam imaging according to an embodiment of the present disclosure;

FIG. 3 shows a flow chart according to step S203 in the embodiment shown in FIG. 2;

FIG. 4 shows a flow chart of a particle beam imaging noise reduction method according to another embodiment of the present disclosure;

5 shows a flow chart of a particle beam imaging noise reduction method according to yet another embodiment of the present disclosure;

Fig. 6 shows a structural block diagram of a particle beam imaging noise reduction device according to an embodiment of the present disclosure.

detailed description

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. Also, for clarity, parts not related to describing the exemplary embodiments are omitted in the drawings.

In the present disclosure, it should be understood that terms such as "comprising" or "having" are intended to indicate the existence of labels, numbers, steps, acts, components, parts or combinations thereof disclosed in this specification, and are not intended to exclude one or multiple other labels, numbers, steps, acts, parts, parts or combinations thereof exist or are added to the possibility.

In addition, it should be noted that, in the case of no conflict, the embodiments in the present disclosure and the labels in the embodiments can be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and embodiments.

Particle beam imaging is widely used in various detection and imaging fields. For example, scanning electron microscopes are currently widely used in various fields such as medicine, materials, biology, and electronics. The imaging quality is the main manifestation of its performance, and reducing the noise in the imaging process is the key to improving its imaging quality.

In the existing scanning electron microscope system, the noise value of all pixels in the image can be obtained by continuously obtaining two scanning electron microscope images of the sample and performing subtraction on the two images. The noise value of all pixels in the image is statistically analyzed to obtain the variance of the noise value, which is used as a characteristic parameter to describe the image noise. Taking the noise characteristic parameter as the objective function, the photographic parameters of the scanning electron microscope image, including spot size, object distance and scanning time, are optimized, and finally a digital image with low noise is obtained.

By applying a spectral transformation to row and column values associated with acquired image frames, basis function components associated with noise can be selectively reduced to provide adjusted row and column values. The adjusted row and column values can be used to generate row and column offset terms to effectively filter noise from the acquired image in an efficient and effective manner.

The existing electron microscope noise reduction method adopts the overall processing of the image, uniform noise reduction, and adopts the same processing method for all lines, which cannot differentiate the different noise characteristics between different lines, and the time-varying tracking of noise The ability is also poor.

Those skilled in the art can understand that other particle beam imaging systems such as electron microscopes and proton imaging systems also face the same or similar problems in addition to scanning electron microscopes.

In order to solve the above problems, the present disclosure proposes a method and device for noise reduction in particle beam imaging.

Fig. 1a shows an exemplary schematic diagram of an implementation scenario of a particle beam imaging noise reduction method according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, FIG. 1 a takes an electron beam of a scanning electron microscope as an example for illustration. The present disclosure is not limited to electron beams, and can also be applied to other particle beams such as proton beams, which is not limited in the present disclosure. Those of ordinary skill in the art can understand that FIG. 1 a is an exemplary schematic diagram of an implementation scene of the particle beam imaging noise reduction method, and does not constitute a limitation to the present disclosure.

As shown in FIG. 1 a , a sample region 102 is included in the imaging region 101 . The electron beam scans in a “Z” shape in the imaging area 101 and passes through the sample area 102 . The row scanning period of the electron beam includes a forward period 103 and a reverse period 104 . The part 1032 of the forward period 103 entering the sample region 102 constitutes the effective time of line scanning; the part 1031 of the forward period 103 before entering the sample region 102 and the reverse period 104 constitute the non-effective time of line scanning.

Scanning electron microscopes have noise on their detectors throughout the entire line scan period of the electron beam. During the effective time of line scanning, the detector of the scanning electron microscope receives the electron beam imaged by the sample, and outputs an image signal of the sample containing noise. During the non-effective time of line scanning, the electron beam is absorbed, reflected, scattered or deflected, and the detector of the scanning electron microscope cannot detect the electron beam imaged by the sample, and outputs a noise signal.

In the embodiments of the present disclosure, during the non-effective time of line scanning, substances that can absorb and/or scatter and/or reflect electron beams can be placed in the path of the electron beams to the imaging region 101, so that the electron beams cannot The imaging area 101 is reached. A magnetic coil may also be used to generate a magnetic field, and/or a pole plate may be used to generate an electric field to deflect the electron beam so that the electron beam cannot reach the imaging region 101 . Those skilled in the art can understand that other ways can also be used to prevent the electron beam from reaching the imaging region 101 , which is not limited in the present disclosure.

In the embodiment of the present disclosure, the average noise signal in one row is obtained after the noise acquired in the non-effective time is averaged. The average noise signal in a row is obtained from the noise obtained in the non-effective time, and the integral processing method may be used, or an average value filter processing method such as Kalman filtering and Wiener filtering may be used, which is not limited in the present disclosure.

In an embodiment of the present disclosure, an image holding operation is performed on the noise-containing sample image signal to obtain the noise-containing sample image signal after image holding. The above-mentioned average processing of the noise obtained in the non-effective time takes a certain amount of time, and the image hold operation can compensate for the time spent on the average processing of the noise obtained in the non-effective time, so that the average noise signal in one row is consistent with the content after the image is held. Noise sample image signals are synchronized in time to facilitate subsequent noise reduction processing.

Those skilled in the art can understand that the image holding operation can be implemented by using an analog delay line, or a digital buffer, or other methods, which are not limited in the present disclosure.

In the embodiment of the present disclosure, the average noise signal in one line is used to perform noise reduction processing on the noise-containing sample image signal after the image is kept, and then the noise-reduced sample image signal is obtained. The noise reduction processing may adopt a Kalman filter method, a fractional order Kalman filter method, or other noise reduction image signal processing methods, which are not limited in the present disclosure.

Those of ordinary skill in the art can understand that, depending on the usage scenario, in addition to calculating the noise mean value for the row-by-row scanning and performing noise reduction processing on the noise-containing sample image signal, the noise can also be calculated in units of 2 lines, 3 lines, etc. The average value is used to perform noise reduction processing on the noise-containing sample image signal, which is not limited in the present disclosure. When the noise characteristics are consistent in multiple rows such as 2 rows and 3 rows, the noise acquired in the non-effective time of the multiple rows can be processed uniformly to obtain the average noise signal in the multiple rows. Since there are more noise signal data, the calculation of the average noise signal is more accurate. Then, the average noise signal in the multiple lines can be used to perform noise reduction processing on the noise-containing sample image signals in the multiple lines after the image is held.

In the embodiment of the present disclosure, the average value of noise in a row can be obtained by analog method and noise reduction processing can be performed on the image signal of the sample containing noise, or the average value of noise in a row can be obtained by digital signal processing and the image signal of sample image containing noise can be processed Noise reduction processing is performed, which is not limited in the present disclosure.

Fig. 1b shows an exemplary schematic diagram of an implementation scene of a particle beam imaging noise reduction method according to an embodiment of the present disclosure. Those skilled in the art can understand that FIG. 1b is an exemplary schematic diagram of an implementation scene of the particle beam imaging noise reduction method, and does not constitute a limitation to the present disclosure.

As shown in FIG. 1 b , the detector 112 of the scanning electron microscope 111 outputs line scanning image signals. The line scanning image signal may be an image signal output by the detector 112 after the scanning electron microscope 111 scans one line. The signal extraction 113 extracts the noise signal from the line scanning image signal during the non-effective time of the line scanning; and extracts the noise-containing sample image signal from the line scanning image signal during the effective time of the line scanning. Referring to Fig. 1a, during the non-effective time of line scanning, substances that can absorb and/or scatter and/or reflect the electron beam can be placed in the path of the electron beam to the imaging area 101, so that the electron beam cannot reach the imaging area 101 , so as to extract the noise signal from the line scanning image signal; it is also possible to use a magnetic coil to generate a magnetic field, and/or use a polar plate to generate an electric field to deflect the electron beam, so that the electron beam cannot reach the imaging area 101, thereby obtaining the image from the line scan Extract the noise signal from the signal. Those skilled in the art can understand that other ways can also be used to prevent the electron beam from reaching the imaging region 101 , which is not limited in the present disclosure.

In the embodiment of the present disclosure, the average noise estimation 114 performs averaging processing on the noise signal to obtain an average noise signal within a row. A capacitor can be used to perform integral processing on the noise signal to obtain an average noise signal within one row. Those skilled in the art can understand that other analog circuit methods can also be used to average the noise signal to obtain the average noise signal in one row, which is not limited in the present disclosure.

In the embodiment of the present disclosure, the image holding 115 performs image holding processing on the noise-containing sample image signal to obtain the noise-containing sample image signal after image holding. The analog delay line can be used to maintain the image, or other methods can be used to maintain the image, which is not limited in the present disclosure.

Noise reduction processing 116 processes the average noise signal in one line and the noise-containing sample image signal after image preservation to obtain the sample image signal after noise reduction. The noise reduction processing 116 may be implemented by using a subtraction circuit, a Kalman filter, or other methods, which are not limited in the present disclosure.

In the embodiment of the present disclosure, the above-mentioned signal extraction 113 , average noise estimation 114 , image preservation 115 , and noise reduction processing 116 are all performed in the analog domain, and the noise-reduced sample image signal in the analog domain is obtained. The analog-to-digital conversion 117 performs analog-to-digital conversion on the noise-reduced sample image signal in the analog domain to obtain the noise-reduced sample image signal in the digital domain for storage or transmission.

Fig. 1c shows an exemplary schematic diagram of an implementation scene of a particle beam imaging noise reduction method according to an embodiment of the present disclosure. Those of ordinary skill in the art can understand that Fig. 1c is an exemplary schematic diagram of an implementation scene of the particle beam imaging noise reduction method, which does not constitute a limitation to the present disclosure.

Fig. 1c includes the same scanning electron microscope 111 and detector 112 as in Fig. 1b.

As shown in FIG. 1 c , the detector 112 of the scanning electron microscope 111 outputs line scanning image signals.

In the embodiment of the present disclosure, the analog-to-digital conversion 121 performs analog-to-digital conversion on the line-scanning image signal in the analog domain to obtain the line-scanning image signal in the digital domain. All processing after the analog-to-digital conversion 121 is performed in the digital domain, thereby improving flexibility.

In the embodiment of the present disclosure, the signal extraction 122 extracts the noise signal from the line scan image signal in the digital domain during the non-effective time of line scan; and extracts the noise signal from the line scan image signal in the digital domain Extract noisy sample image signals. Referring to Fig. 1a, during the non-effective time of line scanning, substances that can absorb and/or scatter and/or reflect the electron beam can be placed in the path of the electron beam to the imaging area 101, so that the electron beam cannot reach the imaging area 101 , so as to extract the noise signal from the line scanning image signal; it is also possible to use a magnetic coil to generate a magnetic field, and/or use a polar plate to generate an electric field to deflect the electron beam, so that the electron beam cannot reach the imaging area 101, thereby extracting the line scanning image signal extract the noise signal. Those skilled in the art can understand that other ways can also be used to prevent the electron beam from reaching the imaging region 101 , which is not limited in the present disclosure.

In the embodiment of the present disclosure, the average noise estimation 123 performs averaging processing on the noise signal to obtain an average noise signal within a row. The average noise estimation 123 may be implemented by using a discrete integral operation, or a Kalman filter, or a Wiener filter, or other average processing methods, which are not limited in the present disclosure.

In the embodiment of the present disclosure, for example, the image holding 124 of the digital buffer performs image holding processing on the noise-containing sample image signal to obtain the noise-containing sample image signal after image holding. Noise reduction processing 125 processes the average noise signal in one row and the noise-containing sample image signal after image preservation to obtain the sample image signal after noise reduction. Noise reduction processing 125 may be implemented by using a Kalman filter, a fractional order Kalman filter or other methods, which are not limited in the present disclosure. The sample image signal after noise reduction is a digital domain signal for storage or transmission.

Fig. 2 shows a flowchart of a method for reducing noise in particle beam imaging according to an embodiment of the present disclosure. As shown in FIG. 2 , the particle beam imaging noise reduction method includes steps S201 , S202 , S203 , S204 , and S205 .

In step S201, a particle beam is used to scan the imaging area in a row to acquire a row-scanning image signal.

In step S202, within the effective time of the row scanning, the first image signal of the row is acquired from the row scanning image signal.

In step S203, during the non-effective time of the row scanning, the noise signal of the row is obtained from the image signal of the row scanning.

In step S204, the average noise signal of the row is obtained according to the noise signal of the row.

In step S205, a second image signal of the row is acquired according to the first image signal of the row and the average noise signal of the row.

In an embodiment of the present disclosure, the line-scanning image signal may be an image signal output by the detector after the scanning electron microscope performs a line-scanning of one line. During the effective time of the row scanning, the first image signal of the row, for example, the noise-containing sample image signal, can be obtained from the row scanning image signal. During the non-effective time of the line scanning, the line noise signal can be obtained from the line scanning image signal. The noise signal of the row is averaged to obtain the average noise signal of the row. The noise-containing sample image signal is subjected to noise reduction processing using the average noise signal of the row to obtain a second image signal of the row, for example, the noise-reduced sample image signal. Those skilled in the art can understand that the particle beam may be an electron beam of a scanning electron microscope or other particle beams, which is not limited in the present disclosure.

According to the technical solution provided by the embodiments of the present disclosure, a line scanning image signal is obtained by using a particle beam to perform line scanning on the imaging area; The first image signal; during the non-effective time of the line scanning, obtain the noise signal of the line from the image signal of the line scanning; according to the noise signal of the line, obtain the average noise signal of the line; according to The first image signal of the row and the average noise signal of the row are obtained to obtain the second image signal of the row, so that the noise in the imaging area is estimated and eliminated row by row, the noise estimation is accurate, and the noise can be well tracked in different Changes in position and time can effectively improve the imaging quality.

In an embodiment of the present disclosure, the effective time of the row scanning may include the time when the particle beam enters the sample region in the forward period of the row scanning; the ineffective time of the row scanning may include: the particle beam is in the In the forward period of the line scan, the time before entering the sample region and/or the time of the particle beam in the reverse period of the line scan. For each line of scanning, the effective time of scanning and the non-effective time of line scanning are set, and the noise can be estimated line by line, and the noise at different positions and different times of the imaging area can be well tracked.

According to the technical solution provided by the embodiments of the present disclosure, the effective time of passing the row scanning includes: the time when the particle beam enters the sample area in the forward period of the row scanning; The effective time includes: the time before the particle beam enters the sample area in the forward period of the row scanning; and/or the time of the particle beam in the reverse period of the row scan, so that the The non-effective time of line scanning can obtain the noise signal without sample information, track the change of noise at different positions and different times well, and improve the accuracy of noise estimation.

FIG. 3 shows a flow chart of step S203 in the embodiment shown in FIG. 2 . As shown in FIG. 3, step S203 in FIG. 2 includes: steps S301 and S302.

In step S301, during the non-effective time of the line scanning, the particle beam is cut off, and the noise signal of the line is obtained from the line scanning image signal.

In step S302, during the non-effective time of the line scanning, the particle beam is deflected, and the noise signal of the line is obtained from the line scanning image signal.

Those skilled in the art can understand that the operations in steps S301 and S302 can be used arbitrarily, or can be used at the same time, which is not limited in the present disclosure.

In the embodiments of the present disclosure, the method of reducing and/or deflecting the particle beam may be used during the non-effective time of the line scanning to prevent the particle beam from reaching the imaging area during the non-effective time of the line scanning, and then the image signal from the line scanning Get the accurate noise signal of the row in .

According to the technical solution provided by the embodiments of the present disclosure, acquiring the noise signal of the row from the row-scanning image signal during the non-effective time of the row-scanning includes: during the non-effective time of the row-scanning, Suppressing the particle beam, obtaining the line noise signal from the line scanning image signal; and/or deflecting the particle beam during the non-effective time of the line scanning, and obtaining the line scanning image signal In order to obtain the noise signal of the row, the particle beam is prevented from reaching the imaging area during the non-effective time of row scanning, and an accurate noise signal is obtained.

In an embodiment of the present disclosure, a substance that absorbs and/or reflects and/or scatters the particle beam may be arranged on the passage where the particle beam enters the imaging area, so as to reduce the particle beam and prevent the particle beam from reaching the imaging area.

According to the technical solution provided by the embodiments of the present disclosure, the attenuation of the particle beam includes: absorbing the particle beam on the passage where the particle beam enters the imaging area, so that the particle beam cannot reach the imaging area and/or reflect the particle beam on the path where the particle beam enters the imaging region, so that the particle beam cannot reach the imaging region; and/or reflect the particle beam on the path that the particle beam enters the imaging region Scattering the particle beam upwards prevents the particle beam from reaching the imaging area, thereby obtaining accurate noise signals.

In embodiments of the present disclosure, coils may be used to generate a magnetic field, and/or plates may be used to generate an electric field, so that the particle beam is deflected and cannot reach the imaging region.

According to the technical solution provided by an embodiment of the present disclosure, the deflecting the particle beam includes: using an electric field and/or a magnetic field to deflect the particle beam on the path where the particle beam enters the imaging region, so that the The particle beam cannot reach the imaging area, so that accurate noise signals can be obtained.

In the embodiments of the present disclosure, the average noise signal of the row can be obtained from the noise signal of the row by using integration processing in the analog domain or digital domain or mean filtering processing such as Kalman filtering and Wiener filtering. Those of ordinary skill in the art can understand that other means of averaging filters in analog or digital domains can also be used, which is not limited in the present disclosure.

According to the technical solution provided by the embodiments of the present disclosure, obtaining the average noise signal of the row according to the noise signal of the row includes: performing integral processing on the noise signal of the row to obtain the average noise signal of the row ; or perform mean value filtering on the noise signal of the row to obtain the average noise signal of the row, thereby obtaining an accurate average noise of the row, and tracking the average noise of the row in different regions and at different times.

In the embodiment of the present disclosure, the hold operation can be performed on the first image signal, such as the sample image signal containing noise, to obtain the third image signal, such as the sample image signal containing noise after the image is held, and then perform the operation with the average noise signal of the row processing to reduce noise, to obtain a second image signal such as a sample image signal after noise reduction.

According to the technical solution provided by an embodiment of the present disclosure, acquiring the second image signal of the row according to the first image signal of the row and the average noise signal of the row includes: performing the first image of the row The signal is held to obtain the third image signal of the row; the average noise signal of the row is subtracted from the third image signal of the row to obtain the second image signal of the row, so that the third image signal Synchronized with the average noise signal of the line, the noise can be eliminated accurately and the image quality can be improved.

In an embodiment of the present disclosure, Kalman filter processing may be used to subtract the row average noise signal from the third image signal, such as the image-holding noise-containing sample image signal. Those skilled in the art can understand that the Kalman filter can be implemented in the analog domain or in the digital domain, and other filter methods such as fractional-order Kalman filter can also be used, which is not limited in the present disclosure.

According to the technical solution provided by an embodiment of the present disclosure, the subtracting the average noise signal of the row from the third image signal of the row includes: using Kalman filter processing to subtract the noise signal from the third image signal of the row The average noise signal of the row, so as to effectively track the average noise of rows in different rows and at different times, reduce the adverse effect of noise in the row on the image quality, and improve the image quality.

Fig. 4 shows a flowchart of a method for reducing noise in particle beam imaging according to another embodiment of the present disclosure. In addition to steps S201 , S202 , S203 , S204 , and S205 that are the same as those in FIG. 2 , FIG. 4 also includes step S401 .

In step S401, the line scanning image signal is converted from an analog signal to a digital signal.

In the embodiments of the present disclosure, the line scan image signal output by the detector can be converted from the analog domain to the digital domain, and subsequent processing is performed in the digital domain, thereby improving flexibility.

According to the technical solution provided by an embodiment of the present disclosure, before acquiring the first image signal of the row from the row-scanning image signal within the effective time of the row-scanning image signal, further includes: converting the row-scanning image signal Converting from analog to digital signals enables most of the processing to be done in the digital domain, increasing flexibility.

Fig. 5 shows a flowchart of a method for reducing noise in particle beam imaging according to yet another embodiment of the present disclosure. In addition to steps S201 , S202 , S203 , S204 , and S205 as in FIG. 2 , FIG. 5 also includes step S501 .

In step S501, the second image signal is converted from an analog signal to a digital signal.

In the embodiments of the present disclosure, the second image signal such as the noise-reduced sample image signal can be converted from the analog domain to the digital domain after all processing is completed, which facilitates storage and transmission of the noise-reduced sample image signal.

According to the technical solution provided by the embodiments of the present disclosure, by further including: converting the second image signal from an analog signal to a digital signal, thereby converting the noise-reduced sample image signal into a digital domain, which facilitates storage and transmission.

Fig. 6 shows a structural block diagram of a particle beam imaging noise reduction device according to an embodiment of the present disclosure.

As shown in Figure 6, the particle beam imaging noise reduction device 600 includes: a line scan image signal acquisition module 601, a first image signal acquisition module 602, a noise signal acquisition module 603, an average noise signal acquisition module 604, a second image signal acquisition module 605.

The line scanning image signal acquisition module 601 is configured to use the particle beam to perform line scanning on the imaging area to acquire line scanning image signals;

The first image signal acquiring module 602 is configured to acquire the first image signal of the line from the line scanning image signal within the effective time of the line scanning;

The noise signal acquiring module 603 is configured to acquire the noise signal of the row from the row-scanning image signal during the non-effective time of the row-scanning;

The average noise signal obtaining module 604 is configured to obtain the average noise signal of the row according to the noise signal of the row;

The second image signal acquisition module 605 is configured to acquire a second image signal of the row according to the first image signal of the row and the average noise signal of the row.

According to the technical solution provided by the embodiments of the present disclosure, the line-scanning image signal acquisition module is configured to use particle beams to perform line-scanning on the imaging area to acquire line-scanning image signals; the first image signal acquisition module is configured to Acquiring the first image signal of the line from the line scanning image signal during the effective time of the line scanning; the noise signal acquisition module is configured to acquire the image from the line scanning during the non-effective time of the line scanning Obtain the noise signal of the row from the signal; the average noise signal acquisition module is configured to acquire the average noise signal of the row according to the noise signal of the row; the second image signal acquisition module is configured to obtain the average noise signal of the row according to the row The first image signal of the row and the average noise signal of the row are obtained to obtain the second image signal of the row, so that the noise in the imaging area is estimated and eliminated row by row, the noise estimation is accurate, and the noise can be well tracked at different positions and different The change of time can effectively improve the imaging quality.

According to the technical solution provided by the embodiments of the present disclosure, the effective time of passing the row scanning includes: the time when the particle beam enters the sample area in the forward period of the row scanning; The effective time includes: the time before the particle beam enters the sample area in the forward period of the row scanning; and/or the time of the particle beam in the reverse period of the row scan, so that the The non-effective time of line scanning can obtain the noise signal without sample information, track the change of noise at different positions and different times well, and improve the accuracy of noise estimation.

According to the technical solution provided by the embodiments of the present disclosure, the noise signal acquisition module includes: a particle beam reduction sub-module configured to reduce the particle beam during the non-effective time of the line scanning, and from the line scanning Obtain the noise signal of the line from the image signal; and/or the particle beam deflection submodule is configured to deflect the particle beam during the non-effective time of the line scanning, and acquire the noise signal from the line scanning image signal The noise signal of the row, so as to prevent the particle beam from reaching the imaging area during the non-effective time of row scanning, and obtain an accurate noise signal.

According to the technical solution provided by the embodiments of the present disclosure, the attenuation of the particle beam includes: absorbing the particle beam on the passage where the particle beam enters the imaging area, so that the particle beam cannot reach the imaging area and/or reflect the particle beam on the path where the particle beam enters the imaging region, so that the particle beam cannot reach the imaging region; and/or reflect the particle beam on the path that the particle beam enters the imaging region Scattering the particle beam upwards prevents the particle beam from reaching the imaging area, thereby obtaining accurate noise signals.

According to the technical solution provided by an embodiment of the present disclosure, the deflecting the particle beam includes: using an electric field and/or a magnetic field to deflect the particle beam on the path where the particle beam enters the imaging region, so that the The particle beam cannot reach the imaging area, so that accurate noise signals can be obtained.

According to the technical solution provided by the embodiments of the present disclosure, the average noise signal acquisition module includes: an integral processing sub-module configured to perform integral processing on the noise signal of the row to obtain the average noise signal of the row; or the mean value The filter processing sub-module is configured to perform mean filtering processing on the noise signal of the row to obtain the average noise signal of the row, thereby obtaining accurate average noise of the row, and tracking the average noise of rows in different regions and at different times.

According to the technical solution provided by the embodiments of the present disclosure, the second image signal acquisition module includes: a third image signal acquisition submodule configured to perform a hold operation on the first image signal of the row to obtain the first image signal of the row The third image signal; the average noise signal reduction sub-module, configured to subtract the average noise signal of the row from the third image signal of the row to obtain the second image signal of the row, so that the third image signal Synchronized with the average noise signal of the line, the noise can be eliminated accurately and the image quality can be improved.

According to the technical solution provided by an embodiment of the present disclosure, the subtracting the average noise signal of the row from the third image signal of the row includes: using Kalman filter processing to subtract the noise signal from the third image signal of the row The average noise signal of the row, so as to effectively track the average noise of rows in different rows and at different times, reduce the adverse effect of noise in the row on the image quality, and improve the image quality.

According to the technical solution provided by the embodiments of the present disclosure, before acquiring the first image signal of the row from the row-scanning image signal within the effective time of the row-scanning, it further includes: a first analog-to-digital conversion module, It is configured to convert the line scanning image signal from an analog signal to a digital signal, so as to realize most of the processing in the digital domain and improve flexibility.

According to the technical solution provided by the embodiments of the present disclosure, it further includes: a second analog-to-digital conversion module configured to convert the second image signal from an analog signal to a digital signal, thereby converting the noise-reduced sample image signal into a digital signal domain for storage and transmission.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in a roadmap or block diagram may represent a module, program segment, or part of code that contains one or more Executable instructions. It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or they may sometimes be executed in the reverse order, depending upon the functionality involved. It should also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by a dedicated hardware-based system that performs the specified functions or operations , or may be implemented by a combination of dedicated hardware and computer instructions.

The units or modules involved in the embodiments described in the present disclosure may be implemented by means of software or hardware. The described units or modules may also be set in the processor, and the names of these units or modules do not constitute limitations on the units or modules themselves in some cases.

As another aspect, the present disclosure also provides a computer-readable storage medium. The computer-readable storage medium may be the computer-readable storage medium included in the node described in the above implementation manner; A computer-readable storage medium assembled in a device. The computer-readable storage medium stores one or more programs, and the programs are used by one or more processors to execute the methods described in the present disclosure.

The above description is only a preferred embodiment of the present disclosure and an illustration of the applied technical principle. It should be understood by those skilled in the art that the scope of the invention involved in this disclosure is not limited to the technical solution formed by the specific combination of the above technical features, but also covers the technical solutions made by the above technical features without departing from the inventive concept. Other technical solutions formed by any combination of or equivalent features thereof. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this disclosure.

Claims (16)

1. A particle beam imaging noise reduction method, comprising:

performing line scanning on the imaging area by using the particle beam to acquire a line scanning image signal;

acquiring a first image signal of the line from the line scanning image signal within the effective time of the line scanning;

acquiring a noise signal of the line from the line scanning image signal in the non-effective time of the line scanning;

acquiring an average noise signal of the row according to the noise signal of the row;

acquiring a second image signal of the line according to the first image signal of the line and the average noise signal of the line;

wherein the effective time of the line scan comprises:

the time during which the particle beam enters the sample area during the forward cycle of the line scan; and/or

The non-active time of the line scan includes:

the time before the particle beam enters the sample area in the forward cycle of the line scan; and/or

The time of the particle beam in a reverse period of the line scan;

the acquiring the noise signal of the line from the line scanning image signal in the non-effective time of the line scanning comprises:

within the non-effective time of the line scanning, reducing the particle beams, and acquiring a noise signal of the line from the line scanning image signal; and/or

Deflecting the particle beam during an inactive time of the line scan to obtain a noise signal of the line from the line scan image signal.

2. The method of claim 1, wherein said attenuating the particle beam comprises:

absorbing the particle beam on a channel of the particle beam entering the imaging area, so that the particle beam cannot reach the imaging area; and/or

Reflecting the particle beam on a channel of the particle beam entering the imaging area, so that the particle beam cannot reach the imaging area; and/or

And scattering the particle beam on a channel of the particle beam entering the imaging area, so that the particle beam cannot reach the imaging area.

3. The method of claim 1, wherein said deflecting said particle beam comprises:

deflecting the particle beam using an electric and/or magnetic field on its way into the imaging region such that the particle beam does not reach the imaging region.

4. The method of claim 1, wherein obtaining the average noise signal of the row according to the noise signal of the row comprises:

performing integration processing on the noise signals of the rows to obtain average noise signals of the rows; or

And carrying out mean value filtering processing on the noise signals of the rows to obtain average noise signals of the rows.

5. The method of claim 1, wherein obtaining the second image signal of the row from the first image signal of the row and the average noise signal of the row comprises:

carrying out holding operation on the first image signals of the row to obtain third image signals of the row;

and subtracting the average noise signal of the line from the third image signal of the line to obtain a second image signal of the line.

6. The method of claim 5, wherein subtracting the row's average noise signal from the row's third image signal comprises:

using a Kalman filtering process, subtracting the average noise signal for the line from the third image signal for the line.

7. The method of claim 1, wherein before acquiring the first image signal of the line from the line scan image signal during the active time of the line scan, further comprising:

and converting the line scanning image signal from an analog signal to a digital signal.

8. The method of claim 1, further comprising:

and converting the second image signal from an analog signal to a digital signal.

9. A particle beam imaging noise reducer, comprising:

a line scanning image signal acquisition module configured to perform line scanning on the imaging region using the particle beam to acquire a line scanning image signal;

a first image signal acquisition module configured to acquire a first image signal of the line from the line scan image signal in an effective time of the line scan;

a noise signal acquisition module configured to acquire a noise signal of the line from the line scan image signal during an inactive time of the line scan;

an average noise signal acquisition module configured to acquire an average noise signal of the row according to the noise signal of the row;

a second image signal acquisition module configured to acquire a second image signal of the line according to the first image signal of the line and the average noise signal of the line;

wherein the effective time of the line scan comprises:

the time the particle beam enters the sample area during the forward cycle of the line scan; and/or

The non-active time of the line scan includes:

the time before the particle beam enters the sample area in the forward cycle of the line scan; and/or

The time of the particle beam in a reverse period of the line scan;

the noise signal acquisition module includes:

a particle beam reduction sub-module configured to reduce the particle beam during an inactive time of the line scan, and to obtain a noise signal of the line from the line scan image signal; and/or

A particle beam deflection sub-module configured to deflect the particle beam during an inactive time of the line scan to obtain a noise signal of the line from the line scan image signal.

10. The apparatus of claim 9, wherein said attenuating the particle beam comprises:

absorbing the particle beam on a channel of the particle beam entering the imaging area, so that the particle beam cannot reach the imaging area; and/or

Reflecting the particle beam on a channel of the particle beam entering the imaging area, so that the particle beam cannot reach the imaging area; and/or

And scattering the particle beam on a channel of the particle beam entering the imaging area, so that the particle beam cannot reach the imaging area.

11. The apparatus of claim 9, wherein said deflecting said particle beam comprises:

deflecting the particle beam using an electric and/or magnetic field on its way into the imaging region such that the particle beam does not reach the imaging region.

12. The apparatus of claim 9, wherein the average noise signal obtaining module comprises:

an integration processing submodule configured to perform integration processing on the noise signals of the rows to obtain average noise signals of the rows; or

And the mean value filtering processing sub-module is configured to perform mean value filtering processing on the noise signals of the rows to obtain average noise signals of the rows.

13. The apparatus of claim 9, wherein the second image signal acquisition module comprises:

a third image signal acquisition sub-module configured to perform a hold operation on the first image signals of the row, resulting in third image signals of the row;

and the average noise signal reduction sub-module is configured to reduce the average noise signal of the row from the third image signal of the row to obtain the second image signal of the row.

14. The apparatus of claim 13, wherein the subtracting the row's average noise signal from the row's third image signal comprises:

using a Kalman filtering process, subtracting the average noise signal for the line from the third image signal for the line.

15. The apparatus according to claim 9, before acquiring the first image signal of the line from the line scan image signal in the active time of the line scan, further comprising:

a first analog-to-digital conversion module configured to convert the line scan image signal from an analog signal to a digital signal.

16. The apparatus of claim 9, further comprising:

a second analog-to-digital conversion module configured to convert the second image signal from an analog signal to a digital signal.

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