WO2021114039A1

WO2021114039A1 - Masking-based automatic exposure control method and apparatus, storage medium, and electronic device

Info

Publication number: WO2021114039A1
Application number: PCT/CN2019/124081
Authority: WO
Inventors: 唐重陈; 黎国武; 李文玉; 易明军
Original assignee: 深圳圣诺医疗设备股份有限公司
Priority date: 2019-12-09
Filing date: 2019-12-09
Publication date: 2021-06-17

Abstract

The present invention relates to a masking-based automatic exposure control method and apparatus, a storage medium, and an electronic device, comprising: S1, performing pre-exposure on an image capture object according to a preset exposure parameter so as to acquire an initial image; S2, acquiring a preset mask according to the image capture object and the initial image, and performing masking on the initial image to acquire a masking image, the preset masking comprising a first selection area and a second selection area; S3, calculating first average grayscale values of all pixel points of the second selection area in the masking image, and acquiring a pixel threshold according to the first average grayscale values; S4, acquiring grayscale values of all pixel points of the first selection area in the masking image, and acquiring pixel points the grayscale values of which being less than the pixel threshold as effective pixel points; S5, calculating second average grayscale values of all of the effective pixel points to serve as effective grayscale values; and S6, acquiring a main exposure parameter according to the effective grayscale values and the preset exposure parameter. By implementing the present invention, the optimal exposure parameter can be acquired so as to acquire optimal photographic images.

Description

Mask-based automatic exposure control method, device, storage medium and electronic equipment

Technical field

The present invention relates to the technical field of image acquisition, and more specifically, to a mask-based automatic exposure control method, device, storage medium and electronic equipment.

Background technique

In many image acquisition processes, for example, digital mammography machines usually calculate the average value of the entire pre-exposure image to obtain the entire corresponding main exposure parameters, which will allow more areas not covered by the object to be measured to be calculated. Among the gray values, the overall average level is too high, and the gray value of the area covered by the test object cannot be accurately calculated, which will seriously affect the setting of the main exposure parameters and affect the acquisition of the final image of the test object.

Secondly, photography equipment such as digital mammography can usually work in a variety of different photography modes, such as: point pressure photography, puncture photography, axillary pressure photography, magnification photography and other modes of different photography areas, the area covered by the measured object and the block. The light area is more flexible. It is also difficult to accurately calculate the gray value of the area covered by the measured object.

technical problem

The technical problem to be solved by the present invention is to provide a mask-based automatic exposure control method, device, storage medium and electronic equipment in view of the above-mentioned defects of the prior art.

Technical solutions

The technical solution adopted by the present invention to solve its technical problems is to construct a mask-based automatic exposure control method, including:

S1. Perform pre-exposure on the subject according to preset exposure parameters, and obtain an initial image after pre-exposure;

S2. Obtain a preset mask according to the subject and the initial image, and perform mask processing on the initial image through the preset mask to obtain a mask image corresponding to the initial image, wherein The preset mask includes a first selection area corresponding to the shooting object and a second selection area set apart from the first selection area;

S3. Calculate the first average grayscale value of all pixels corresponding to the second selection area in the mask image, and obtain a pixel threshold value according to the first average grayscale value;

S4. Obtain grayscale values of all pixels corresponding to the first selection area in the mask image, and obtain pixels with grayscale values less than the pixel threshold as effective pixels;

S5. Calculate the second average grayscale value of all effective pixels and use the second average grayscale value as the effective grayscale value;

S6. Obtain a main exposure parameter according to the effective grayscale value and the preset exposure parameter.

Preferably, a mask-based automatic exposure control method of the present invention further includes:

S41. Obtain the occupation ratio of the effective pixels in the first selected area, and confirm whether the occupation ratio meets a preset condition, if yes, execute the step S5, if not, execute the step S42;

S42. Obtain a third average grayscale value of all pixels corresponding to the first selected area in the mask image, and execute the step S6.

Preferably, in the step S41, the occupation ratio is greater than or equal to one-eighth.

Preferably, in the step S2,

The first selection area includes a plurality of first selection areas that are isolated from each other; and/or

The first selection area is set corresponding to the shooting object.

Preferably, in the step S3, the obtaining the pixel threshold value according to the first average gray scale value includes: taking a half of the first average gray scale value as the pixel threshold value.

Preferably, in the step S6, the obtaining the main exposure parameter according to the effective grayscale value and the preset exposure parameter includes obtaining the main exposure parameter by using the following formula:

A=(B/C)*D;

Wherein A is the main exposure parameter, B is the target grayscale value, C is the effective grayscale value, and D is the preset exposure parameter.

Preferably, the main exposure parameter includes the exposure amount of the main exposure, and the preset exposure parameter includes the exposure amount of the pre-exposure.

The present invention also constructs a mask-based automatic exposure control device, including:

The first processing unit is configured to perform pre-exposure on the subject according to preset exposure parameters, and obtain an initial image after pre-exposure;

The second processing unit is configured to obtain a preset mask according to the photographic subject and the initial image, and perform mask processing on the initial image through the preset mask to obtain a mask corresponding to the initial image An image, wherein the preset mask includes a first selection area corresponding to the shooting object and a second selection area set apart from the first selection area;

A first calculation unit, configured to calculate a first average gray scale value of all pixels corresponding to the second selection area in the mask image, and obtain a pixel threshold value according to the first average gray scale value;

An acquiring unit, configured to acquire grayscale values of all pixels corresponding to the first selection area in the mask image, and acquire pixels whose grayscale values are less than the pixel threshold as effective pixels;

The second calculation unit is configured to calculate the second average gray scale value of all effective pixels and use the second average gray scale value as the effective gray scale value;

The third processing unit is configured to obtain the main exposure parameter according to the effective grayscale value and the preset exposure parameter.

The present invention also constructs a computer storage medium on which a computer program is stored, and when the computer program is executed by a processor, the automatic exposure control method based on a mask as described in any one of the above is realized.

The present invention also constructs an electronic device, including a memory and a processor;

The memory is used to store a computer program;

The processor is configured to execute the computer program to implement the mask-based automatic exposure control method as described in any one of the above.

Beneficial effect

A mask-based automatic exposure control method, device, storage medium, and electronic equipment implemented in the present invention have the following beneficial effects: the best exposure parameter can be obtained to obtain the best photographic image.

Description of the drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the accompanying drawings:

FIG. 1 is a program flowchart of an embodiment of the mask-based automatic exposure control method of the present invention;

2 is a program flowchart of another embodiment of the mask-based automatic exposure control method of the present invention;

Fig. 3 is a logical block diagram of an embodiment of the mask-based automatic exposure control device of the present invention.

Embodiments of the present invention

In order to have a clearer understanding of the technical features, objectives and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, in an embodiment of the mask-based automatic exposure control method of the present invention, it includes:

S1. Pre-exposure the subject according to preset exposure parameters to obtain the initial image after pre-exposure; specifically, take a digital mammography machine as an example. When the subject is taken, the position of the subject is correct and the state is When the preparation is complete, you can first set the preset exposure parameters for photographing the test object according to the characteristic parameters of the test object, and obtain the pre-exposed initial image of the test object through the preset exposure parameters. Here, the preset exposure parameters of the test object can be obtained by entering the automatic exposure mode to obtain the corresponding preset exposure parameters through the fully automatic exposure mode, and perform fully automatic pre-exposure through the preset exposure parameters. In some implementations, the preset exposure parameters can also be set according to empirical values. When setting the empirical values, the type of the tested object and the test position can also be used as the basis for setting the empirical values at the same time.

S2. Obtain a preset mask according to the shooting object and the initial image, and perform mask processing on the initial image through the preset mask to obtain a mask image corresponding to the initial image, where the preset mask includes a first mask corresponding to the shooting object. A selection area and a second selection area set apart from the first selection area; specifically, after the initial image is acquired, a corresponding preset mask is set according to the acquired initial image and the shooting object, and the mask may be 1 with the initial image. :1 ratio pixel size. And mask the initial image through the preset mask, so that the mask image corresponding to the initial image is obtained, and the formed mask image includes the first selection area corresponding to the shooting object and the first selection area In order to ensure that the first selection area can be better distinguished from the second selection area, the second selection area can be set farther from the first selection area. In an embodiment, the second selection area may be set at a position away from the first selection area and close to the edge of the initial image. The setting of the preset mask can be set according to the subject. For example, when performing mammography, it can be pre-masked according to the regional breast characteristics, that is, according to the size of the subject, the appropriate preset mask can be selected to make the subject Try to fall within the first constituency. When the photographing equipment is determined, the photographing object is also certain. For example, when the photographing equipment is a digital mammography machine, the photographic object can be understood as performing mammography. Then, the preset masks corresponding to different breasts can be set according to the physical characteristics of the breasts. sheet. At the same time, the preset mask settings also correspond to the initial image. It can be understood that the acquisition of the initial image corresponds to the photography mode of the photography equipment. For example, the photography modes of the digital breast machine include point pressure photography, puncture photography, axillary pressure photography, For different photography modes such as magnification photography, the initial image obtained is also different according to the photography mode. When selecting the preset mask, you must fully consider the actual initial image obtained, or the comparison with the initial image. Set the photography mode to select the appropriate preset mask. It can be understood here that the obtained mask image actually contains three regions, of which the first and second selections are bare selections. Excluding the first and second selections is the mask selection. The mask selection is Think of it as the background, and in the subsequent processing, the mask selection will not be processed.

S3. Calculate the first average grayscale value of all pixels corresponding to the second selection area in the mask image, and obtain the pixel threshold value according to the first average grayscale value; specifically, the second selection area is set at intervals from the first selection area, and One selection area corresponds to the measured object, and the second selection area can be understood as a different area from the measured object. At this time, the average value of all pixels in the second selected area, that is, the first average grayscale value, can be obtained, and then a pixel threshold value can be set according to the first average grayscale value. In order to avoid the impact of bad pixels, the second selection area has at least 10 pixels.

S4. Obtain the grayscale values of all pixels corresponding to the first selected area in the mask image, and obtain the pixels whose grayscale values are less than the pixel threshold value as effective pixels; specifically, yes, in the first selected area in the mask image Pixels are processed to obtain the grayscale value of all pixels in the first selection area, and the grayscale value of each pixel is compared with the pixel threshold respectively, and the pixels whose grayscale value is greater than or equal to the pixel threshold are discarded, and only the A pixel with a grayscale value less than the pixel threshold is corresponding to the effective pixel. In this way, all the effective pixels in the first selection area are obtained.

S5. Calculate the second average gray scale value of all effective pixels and use the second average gray scale value as the effective gray scale value; specifically, calculate the average gray scale value of all effective pixels obtained above, that is, the second average gray scale Value, and use the second average grayscale value as the effective grayscale value.

S6. Obtain the main exposure parameter according to the effective grayscale value and the preset exposure parameter. Specifically, after the effective grayscale value is obtained, the main exposure parameter can be obtained according to the preset exposure parameter corresponding to the effective grayscale value, so as to perform main exposure by setting the main exposure parameter to obtain the best photographic image.

As shown in FIG. 2, in another embodiment of the mask-based automatic exposure control method of the present invention, it further includes:

S41. Obtain the occupation ratio of the effective pixels in the first selection area, and confirm whether the occupation ratio meets the preset condition, if yes, execute step S5, if not, execute step S42;

S42: Obtain the third average grayscale value of all pixels corresponding to the first selected area in the mask image as an effective grayscale value, and execute step S6.

Specifically, for the situation that the subject may completely block the second selection area, after obtaining all the effective pixels in the first selection area, obtain the proportion of all effective pixels in all the pixels in the first selection area, and The occupancy ratio is judged. When the occupancy ratio meets the preset conditions, it can be determined that the second selection area is not completely obscured by the subject at this time, and the pixels corresponding to the second selection area in the mask image are actually the pixels corresponding to the subject At this time, step S5 is executed, that is, only the effective pixels in the first selection area are processed. When the occupancy ratio does not meet the preset conditions, it can be determined that the second selection area is completely occluded by the subject at this time, and the pixels corresponding to the second selection area in the mask image are actually part of the pixels corresponding to the subject. Determining the corresponding pixels in the first selection area can be understood as all the pixels of the shooting object. At this time, all pixels corresponding to the first selection area can be calculated to obtain the average gray scale value, that is, the third average gray scale value. The third average grayscale value is defined as the effective grayscale value, and step S6 is executed according to the effective grayscale value to obtain the corresponding main exposure parameter.

In one embodiment, in step S41, the occupation ratio is greater than or equal to one-eighth. Specifically, the size of the first selection area will affect the proportion of the object that is occluded. To judge the occupation ratio, the occupation ratio can be set to be greater than or equal to one-eighth of the number of all pixels in the first selection area when the occupation ratio meets the preset condition. The value of the occupation ratio can be selected according to the shooting object .

In one embodiment, in step S2, the first selection area includes a plurality of first selection areas isolated from each other; in another embodiment, the first selection area is set corresponding to the shooting object. Specifically, according to the shooting mode of the subject, the first selection area may be a plurality of first selection areas isolated from each other. For example, in the digital mammography machine's photography mode is zoomed point-pressure photography, it may acquire images of multiple contact points. In this case, the first selection area can be set for multiple contact points. In addition, the first selection area should be set as much as possible. Corresponding to the subject to try to ensure that the pixel corresponding to the subject falls within the first selection area.

In one embodiment, in step S3, obtaining the pixel threshold value according to the first average gray scale value includes: taking a half of the first average gray scale value as the pixel threshold value. Specifically, the acquisition process of the pixel threshold value may take a value of one-half of the first average grayscale value. The pixel threshold can be obtained through clinical experiments. For example, if the threshold needs to cover a subject greater than or equal to 5mm without being lost, a 5mm BR5050 test body membrane is used to place the first selected area, and after exposure to common clinical conditions with this thickness, use Measuring tools to test the grayscale values of the first and second selections respectively. The ratio of the first selection area to the second selection area is the value of the pixel threshold.

In one embodiment, in step S6, obtaining the main exposure parameter according to the effective grayscale value and the preset exposure parameter includes obtaining the main exposure parameter using the following formula: A=(B/C)*D; where A is the main exposure parameter, B is the target grayscale value, C is the effective grayscale value, and D is the preset exposure parameter. Specifically, the target grayscale value is configured according to the selected detector components, and is a configurable constant; according to this formula, the optimal exposure parameters of the main exposure can be obtained.

Further, the main exposure parameter includes the exposure amount of the main exposure, and the preset exposure parameter includes the exposure amount of the pre-exposure. Specifically, on the basis of the above, the acquired main exposure parameter includes the exposure amount of the main exposure, which is acquired according to the exposure amount of the pre-exposure.

In addition, a mask-based automatic exposure control device of the present invention includes:

The first processing unit 110 is configured to pre-expose the subject according to preset exposure parameters to obtain an initial image after the pre-exposure;

The second processing unit 120 is configured to obtain a preset mask according to the shooting object and the initial image, and perform mask processing on the initial image through the preset mask to obtain a mask image corresponding to the initial image, wherein the preset mask includes A first selection area corresponding to the photographed object and a second selection area set apart from the first selection area;

The first calculation unit 130 is configured to calculate the first average gray scale value of all pixels corresponding to the second selection area in the mask image, and obtain the pixel threshold value according to the first average gray scale value;

The obtaining unit 140 is configured to obtain the grayscale values of all pixels corresponding to the first selection area in the mask image, and obtain the pixels whose grayscale values are less than the pixel threshold value as effective pixels;

The second calculation unit 150 is configured to calculate the second average gray scale value of all effective pixels and use the second average gray scale value as the effective gray scale value;

The third processing unit 160 is configured to obtain the main exposure parameter according to the effective grayscale value and the preset exposure parameter.

Specifically, the specific coordination operation process between the units of the mask-based automatic exposure control device can refer to the above-mentioned mask-based automatic exposure control method, which will not be repeated here.

In addition, an electronic device of the present invention includes a memory and a processor; the memory is used to store a computer program; the processor is used to execute the computer program to implement any of the above mask-based automatic exposure control methods. Specifically, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, when the computer program can be downloaded and installed through an electronic device and executed, it executes the above-mentioned functions defined in the method of the embodiment of the present invention. The electronic device in the present invention can be a terminal such as a notebook, a desktop computer, a tablet computer, a smart phone, etc., or a server.

In addition, a computer storage medium of the present invention has a computer program stored thereon, and when the computer program is executed by a processor, it implements any one of the above mask-based automatic exposure control methods. Specifically, it should be noted that the above-mentioned computer-readable medium of the present invention may be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or a combination of any of the above. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable Programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above. In the present invention, the computer-readable storage medium may be any tangible medium that contains or stores a program, and the program may be used by or in combination with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium may include a data signal propagated in a baseband or as a part of a carrier wave, and a computer-readable program code is carried therein. This propagated data signal can take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. The computer-readable signal medium may also be any computer-readable medium other than the computer-readable storage medium. The computer-readable signal medium may send, propagate, or transmit the program for use by or in combination with the instruction execution system, apparatus, or device . The program code contained on the computer-readable medium can be transmitted by any suitable medium, including but not limited to: wire, optical cable, RF (radio frequency), etc., or any suitable combination of the above.

The above-mentioned computer-readable medium may be included in the above-mentioned electronic device; or it may exist alone without being assembled into the electronic device.

It is understandable that the above examples only express the preferred embodiments of the present invention, and the descriptions are more specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention; it should be pointed out that for those of ordinary skill in the art In other words, without departing from the concept of the present invention, the above technical features can be freely combined, and several modifications and improvements can be made. These all belong to the scope of protection of the present invention; therefore, everything that follows the scope of the claims of the present invention All equivalent changes and modifications shall fall within the scope of the claims of the present invention.

Claims

A mask-based automatic exposure control method is characterized in that it includes:

S1. Perform pre-exposure on the subject according to preset exposure parameters, and obtain an initial image after pre-exposure;

S2. Obtain a preset mask according to the subject and the initial image, and perform mask processing on the initial image through the preset mask to obtain a mask image corresponding to the initial image, wherein The preset mask includes a first selection area corresponding to the shooting object and a second selection area set apart from the first selection area;

S3. Calculate the first average grayscale value of all pixels corresponding to the second selection area in the mask image, and obtain a pixel threshold value according to the first average grayscale value;

S4. Obtain grayscale values of all pixels corresponding to the first selection area in the mask image, and obtain pixels with grayscale values less than the pixel threshold as effective pixels;

S5. Calculate the second average grayscale value of all effective pixels and use the second average grayscale value as the effective grayscale value;

S6. Obtain a main exposure parameter according to the effective grayscale value and the preset exposure parameter.
The mask-based automatic exposure control method according to claim 1, wherein the method further comprises:

S41. Obtain the occupation ratio of the effective pixels in the first selection area, and confirm whether the occupation ratio meets a preset condition, if yes, execute the step S5, if not, execute the step S42;

S42. Obtain a third average grayscale value of all pixels corresponding to the first selected area in the mask image, and execute the step S6.
The mask-based automatic exposure control method according to claim 2, wherein in the step S41, the occupation ratio is greater than or equal to one-eighth.
The mask-based automatic exposure control method according to claim 1, wherein in the step S2,

The first selection area includes a plurality of first selection areas that are isolated from each other; and/or

The first selection area is set corresponding to the shooting object.
The mask-based automatic exposure control method according to claim 1, wherein in the step S3, the obtaining the pixel threshold value according to the first average gray level value comprises: using the first average gray level value One half of the order value is the pixel threshold value.
The mask-based automatic exposure control method according to claim 1, wherein, in the step S6, the obtaining the main exposure parameter according to the effective grayscale value and the preset exposure parameter comprises using the following Formula to obtain the main exposure parameters:

A=(B/C)*D;

Wherein A is the main exposure parameter, B is the target grayscale value, C is the effective grayscale value, and D is the preset exposure parameter.
The mask-based automatic exposure control method according to claim 6, wherein the main exposure parameter includes the exposure amount of the main exposure, and the preset exposure parameter includes the exposure amount of the pre-exposure.
A mask-based automatic exposure control device is characterized in that it comprises:

The first processing unit is configured to perform pre-exposure on the subject according to preset exposure parameters, and obtain an initial image after pre-exposure;

The second processing unit is configured to obtain a preset mask according to the photographic object and the initial image, and perform mask processing on the initial image through the preset mask to obtain a mask corresponding to the initial image An image, wherein the preset mask includes a first selection area corresponding to the shooting object and a second selection area set apart from the first selection area;

A first calculation unit, configured to calculate a first average gray scale value of all pixels corresponding to the second selection area in the mask image, and obtain a pixel threshold value according to the first average gray scale value;

An acquiring unit, configured to acquire grayscale values of all pixels corresponding to the first selection area in the mask image, and acquire pixels with grayscale values less than the pixel threshold as effective pixels;

The second calculation unit is configured to calculate the second average gray scale value of all effective pixels and use the second average gray scale value as the effective gray scale value;

The third processing unit is configured to obtain the main exposure parameter according to the effective grayscale value and the preset exposure parameter.
A computer storage medium with a computer program stored thereon, wherein the computer program implements the mask-based automatic exposure control method according to any one of claims 1-7 when the computer program is executed by a processor.
An electronic device, characterized in that it includes a memory and a processor;

The memory is used to store a computer program;

The processor is configured to execute the computer program to implement the mask-based automatic exposure control method according to any one of claims 1-7.

To