阅读说明：本技术 光射野视觉检测方法及光射野视觉检测设备 (Light radiation field visual detection method and light radiation field visual detection equipment ) 是由 郑永明 杨建勇 于 2019-11-14 设计创作，主要内容包括：本发明涉及一种光射野视觉检测方法及光射野视觉检测设备,所述光射野视觉检测方法包括以下步骤：获取摄像模组拍摄的X光机射野指示灯发出的可见光形成的光野图像,所述光野图像包括被照亮的光野区域；获取所述摄像模组拍摄的X光机发出的X射线照射在射野检测板上的射野图像,所述射野图像包括射野区域；分析所述光野图像获取所述光野区域的图像属性；分析所述射野图像获取所述射野区域的图像属性；及依据所述光野区域及所述射野区域的图像属性计算所述X光机的光射野一致性参数,所述X光机的光射野一致性参数包括所述射野区域相对于所述光野区域的偏移量参数。(The invention relates to a light radiation field visual detection method and a light radiation field visual detection device, wherein the light radiation field visual detection method comprises the following steps: acquiring a light field image formed by visible light emitted by an X-ray machine light field indicator lamp shot by a camera module, wherein the light field image comprises an illuminated light field area; acquiring a field image which is shot by the camera module and is irradiated on a field detection plate by X-rays emitted by an X-ray machine, wherein the field image comprises a field area; analyzing the light field image to obtain the image attribute of the light field area; analyzing the portal image to acquire the image attribute of the portal area; and calculating the light field consistency parameter of the X-ray machine according to the light field area and the image attribute of the light field area, wherein the light field consistency parameter of the X-ray machine comprises an offset parameter of the light field area relative to the light field area.)

1. A light field visual inspection method comprises the following steps:

step S11, acquiring a light field image formed by visible light emitted by an X-ray machine light field indicator lamp shot by a camera module, wherein the light field image comprises an illuminated light field area;

step S12, acquiring a portal image formed by irradiating X-rays emitted by the X-ray machine and shot by the camera module on a portal detection plate, wherein the portal image comprises a portal area;

step S13, analyzing the light field image to obtain the image attribute of the light field area;

step S14, analyzing the portal image to obtain the image attribute of the portal area; and

step S15, calculating the light field consistency parameter of the X-ray machine according to the light field area and the image attribute of the light field area, wherein the light field consistency parameter of the X-ray machine comprises the offset parameter of the light field area relative to the light field area.

2. The light field vision inspection method of claim 1, characterized by: each boundary line of the light field area is provided with a preset point, two preset points define a straight line perpendicular to the boundary line, the light field area defines a plurality of adjusting points corresponding to the preset points, the adjusting points are intersection points of the boundary line of the light field area and the straight line defined by the corresponding preset points, and the offset parameter of the light field area relative to the light field area comprises the offset distance of each adjusting point of the light field area relative to the corresponding preset point of the light field area.

3. The light field vision inspection method of claim 2, characterized by: the image attributes of the light field region and the light field region comprise a central position, a length, a width and a rotation angle.

4. The light field vision inspection method of claim 2, characterized by: the step of calculating the light field consistency parameter of the X-ray machine according to the light field area and the image attribute of the light field area comprises the following steps:

calculating the coordinates of each preset point and the coordinates of any two points on a straight line defined by the preset points according to the image attributes of the light field area;

calculating the coordinates of any two points on the boundary line of the field area according to the image attributes of the field area;

calculating the coordinates of the adjusting points according to a calculation formula of the intersection point of the two intersecting straight lines; and

and calculating the offset distance of each adjusting point of the radiation field area relative to the corresponding preset point of the light field area by using a calculation formula of the distance between two points according to the coordinates of each preset point and the coordinates of the corresponding adjusting point.

5. The light field vision inspection method of claim 1, characterized by: the step of obtaining the portal image formed by the X-ray emitted by the X-ray machine and shot by the camera module comprises the following steps:

acquiring at least two images formed by X rays emitted by the X-ray machine and shot by the camera module; and

and analyzing and acquiring an image with a higher brightness value in the at least two images as the portal image.

6. The light field vision inspection method of claim 5, characterized by: the step of analyzing and acquiring the image with higher brightness value in the at least two images as the portal image comprises:

step S1, acquiring the image and the brightness value of the current camera module;

step S2, determining whether the brightness value of the current image is greater than a preset threshold, if the brightness value of the current image is less than or equal to the preset threshold, executing step S1, and if the brightness value of the current image is greater than the preset threshold, executing step S3;

step S3, taking the current image as the image with the highest brightness value, updating the preset threshold value to the brightness value of the current image, starting a timer, and executing step S4;

step S4, determining whether the time from the first time of acquiring the image to the current image exceeds the preset timer time, if the time from the first time of acquiring the image to the current image is greater than or equal to the preset timer time, executing step S5, and if the time from the first time of acquiring the image to the current image is less than the preset timer time, executing step S1;

and step S5, outputting the image with the highest brightness value as a portal image.

7. The light field vision inspection method of claim 5, characterized by:

the step of obtaining the light field image formed by the visible light emitted by the X-ray machine light field indicating lamp shot by the camera module comprises the following steps: the size of the X-ray machine light field area is adjusted and projected onto the light field detection plate, the camera module shoots the light field image and receives the light field image shot by the camera module.

8. The light field vision inspection method of claim 1, characterized by: the step of analyzing the light field image or the light field image to obtain the image attribute of the light field region or the light field region comprises:

carrying out binarization filtering on the light field image or the radiation field image;

analyzing the light field image or the radiation field image after the binaryzation filtering to obtain a contour graph; and

and calculating a minimum circumscribed rectangular area corresponding to the outline pattern, and taking the minimum circumscribed rectangular area as the light field area or the radiation field area.

9. The light field vision inspection method of claim 8, characterized by: the step of calculating the minimum circumscribed rectangular area corresponding to the outline figure comprises the following steps:

step a1, calculating a circumscribed rectangle of the outline graph according to a direct calculation method, taking an original circumscribed rectangle of the outline graph as a minimum circumscribed rectangle RectMin, recording the length, the width and the area of the minimum circumscribed rectangle RectMin, assigning the area of the minimum circumscribed rectangle RectMin to a first variable AreaMin, and setting a rotation angle α to be 0 degree;

step a2, rotating the outline graph by theta degrees, calculating the minimum circumscribed rectangle RectTmp after the radiation field outline graph is rotated according to the step a1, and assigning the area of the minimum circumscribed rectangle RectTp to a second variable AreaTmp;

step a3, setting a rotation angle α to α + theta, comparing the sizes of the first variable AreaTmp and the second variable AreaMin, assigning the value with the smaller area to AreaMin, assigning the rotation angle α at the moment to β to α, and assigning rectangle information to a circumscribed rectangle RectMin to RectTmp;

a4, circularly executing the steps a2 and a3 until a minimum circumscribed rectangle RectMin and a rotation angle α corresponding to the minimum circumscribed rectangle RectMin are finally obtained, and

step a5, reversely rotating the minimum circumscribed rectangle RectMin calculated in step a4 by an angle β, thereby obtaining the minimum circumscribed rectangle area as the light field area or the radiation field area.

10. A light field vision inspection device, characterized by: the light radiation field visual detection equipment comprises a light radiation field image acquisition device and a control device, the light radiation field image acquisition device comprises a camera module, a light field detection plate and a radiation field detection plate, the camera module is used for acquiring a light field image formed by visible light emitted by the X-ray machine light field indicator and acquiring a light field image formed by X-rays emitted by the X-ray machine irradiating on the light field detection plate, the light field image comprises an illuminated light field area, the portal image comprises a portal area, the control device analyzes the light field image, calculates the image attribute of the light field area, analyzes the portal image, calculates the image attribute of the portal area, and calculates the light field consistency parameter of the X-ray machine according to the light field area and the image attribute of the portal area, the light field consistency parameter of the X-ray machine comprises an offset parameter of the light field area relative to the light field area.

11. The light portal vision inspection device of claim 10, wherein: the light field detection plate is a transparent organic glass plate with cross scale marks, visible light emitted by the X-ray machine light field indicating lamp is projected onto the light field detection plate to form a light field area, and the camera module shoots the light field detection plate to obtain a light field image; the field detection plate is an X-ray fluorescent plate, when X-rays emitted by the X-ray machine irradiate the field detection plate, the irradiated part can be excited to emit fluorescence to form a field area, and the camera module shoots the field detection plate to obtain a field image.

12. The light portal vision inspection device of claim 10, wherein: the light field image acquisition device further comprises a camera module and a shell, wherein the shell comprises a box body and a cover body with an opening, the opening is used for arranging the light field detection plate, the cover body is used for installing the light field detection plate and is used for covering one side of the opening of the box body, and the camera module is contained in the box body and is used for shooting corresponding to the opening to acquire the light field image and the light field image.

13. The light portal vision inspection device of claim 12, wherein: the camera shooting module comprises a sliding structure, a sliding block and a camera, the sliding structure is fixed in the box body, the camera is arranged on the sliding block, the sliding block is in sliding fit with the sliding structure to drive the camera to move, the object distance of a shot image is adjusted to ensure that a clear image is obtained, and the sliding direction of the sliding block and the sliding structure faces towards the opening or is far away from the opening.

14. The light portal vision inspection device of claim 13, wherein: the box body comprises a bottom plate and a side wall connected to the periphery of the bottom plate, the camera module further comprises a fixed plate, the fixed plate is fixed on the bottom plate, and the sliding structure is fixed on the fixed plate so as to be fixed in the box body; the cover body is also pivoted with the edge of the box body, so that the field detection plate on the cover body can be selectively arranged corresponding to the opening.

15. The light portal vision inspection device of claim 14, wherein: the sliding structure comprises a sliding groove for accommodating the sliding block in a sliding mode, the sliding block comprises a sliding portion and connecting portions connected to two ends of the sliding portion, the two connecting portions are used for being fixed to two ends of the camera respectively, and at least parts of the sliding portion and the connecting portions are accommodated in the sliding groove in a sliding mode.

16. The light portal vision inspection device of claim 15, wherein: the light field image acquisition device further comprises a communication module, and the camera is further used for receiving a control signal for shooting through the communication module and transmitting the light field image and the field image obtained by shooting to the control device.

Technical Field

The invention relates to a light field detection technology, in particular to a light field visual detection method and light field visual detection equipment for an X-ray machine.

Background

The light field refers to the area defined by the simulated light of the head of the X-ray machine (i.e. the X-ray camera) on the incident surface. The radiation field refers to the projection of the X-ray beam of the X-ray machine on the incident surface, and is precisely the region defined by 50% of the dose intensity in the central region of the beam. In clinical diagnostic examinations, the field cannot be visually confirmed, and therefore, the field is usually simulated by visible light. The light field consistency detection is mainly used for verifying the overlapping degree of the light field formed by lamplight and the light field formed by X-ray, including the deviation degree of the light field and the center or the boundary of the light field.

The consistency of the light field and the radiation field has important significance for clinical diagnosis photography: the medical examination efficiency can be improved, the integrity of the examined part is ensured, the condition of waste films caused by the defect of the examined part is reduced, the technical unnecessary irradiation of the examined person is avoided, the life-long medical irradiation dose level of the public is reduced, and the cancer cases caused by radiation are reduced.

In China, the following specifications and standards have provided detection requirements for the consistency of the light field of the X-ray machine: WS76-2017 medical routine X-ray diagnostic equipment quality control standard, JJG 744-2004 medical diagnostic X-ray radiation source, JJG1078-2012 medical digital radiography (CR, DR) system X-ray radiation source verification procedure, and the like.

Specifically, the light field consistency detection method of the conventional X-ray machine includes the following steps:

1) film imaging method-principle is that different thickness high density metal absorbs difference to X ray, and the etching scales of the detecting board (these scales are used to align the light field in advance) are imaged on the film, and finally the difference degree between the light field and the light field is judged by the film;

2) fluorescence method, which utilizes the fact that after some fluorescent materials are excited (irradiated), the fluorescence afterglow time is long, and the difference between a light-emitting area and a light field aligned in advance is observed in a darkroom by naked eyes to determine the difference between the light-emitting area and the light field;

3) a fluorescent video recording method, which uses the camera shooting technique to pick up the luminous image of a special detection board printed with a scale, needs to put the video file of the sd card on the video recorder on a computer after the image is recorded by the camera shooting device, and then pauses when the luminous image is seen. And then the video is amplified, and a person looks at the image and the graduated scale.

However, the above method has some drawbacks:

1) film imaging method: this is a classical method with the disadvantages of film development, time consumption, high use cost (calculated film cost);

2) fluorescence method: the method is mainly developed for radiotherapy, and has the disadvantages of high price (imported products), large exposure and incapability of storing data. Because of needing darkroom observation and fast fluorescence brightness attenuation, the detection process is laborious, and meanwhile, because the sharpness of the fluorescence boundary is not enough, the measurement error is larger;

3) the fluorescent video recording method comprises a detection plate, a camera device and a data receiving and storing device, and is relatively complex, and has the disadvantages that ① fixes the camera from the upper part, the camera needs to search the angle and the distance, the focus is adjusted each time, the image definition is influenced, ② reading is artificial, an sd card of the camera needs to be inserted into a computer, a player is used, the brightest frame of image is artificially judged, the player is paused, the eye diseases and the hands are fast, the edge blurring is artificially estimated by reading the data on a graduated scale, and the artificial influence factor is too large.

Disclosure of Invention

In order to solve the above-mentioned problems in the prior art, it is necessary to provide a light field visual inspection method and a light field visual inspection apparatus for an X-ray machine, which have at least one of the advantages of low cost, small measurement error and small human influence factor.

An embodiment of the present invention provides a light field visual inspection method, which includes the following steps:

step S11, acquiring a light field image formed by visible light emitted by an X-ray machine light field indicator lamp shot by a camera module, wherein the light field image comprises an illuminated light field area;

step S12, acquiring a portal image formed by irradiating X-rays emitted by the X-ray machine and shot by the camera module on a portal detection plate, wherein the portal image comprises a portal area;

step S13, analyzing the light field image to obtain the image attribute of the light field area;

step S14, analyzing the portal image to obtain the image attribute of the portal area; and

step S15, calculating the light field consistency parameter of the X-ray machine according to the light field area and the image attribute of the light field area, wherein the light field consistency parameter of the X-ray machine comprises the offset parameter of the light field area relative to the light field area.

In one embodiment, each boundary line of the light field region has a preset point, two preset points define a straight line perpendicular to the boundary line, the light field region defines a plurality of adjustment points corresponding to the preset points, the adjustment points are intersections of the boundary line of the light field region and the straight line defined by the corresponding preset points, and the offset parameter of the light field region relative to the light field region includes an offset distance of each adjustment point of the light field region relative to the corresponding preset point of the light field region.

In one embodiment, the image attributes of the light field region and the light field region each include a center position, a length, a width, and a rotation angle.

In one embodiment, the step of calculating the light field consistency parameter of the X-ray machine according to the light field area and the image attribute of the light field area comprises:

calculating the coordinates of each preset point and the coordinates of any two points on a straight line defined by the preset points according to the image attributes of the light field area;

calculating the coordinates of any two points on the boundary line of the field area according to the image attributes of the field area;

calculating the coordinates of the adjusting points according to a calculation formula of the intersection point of the two intersecting straight lines; and

and calculating the offset distance of each adjusting point of the radiation field area relative to the corresponding preset point of the light field area by using a calculation formula of the distance between two points according to the coordinates of each preset point and the coordinates of the corresponding adjusting point.

In an embodiment, the step of acquiring a portal image formed by the X-rays emitted by the X-ray machine and captured by the camera module includes:

acquiring at least two images formed by X rays emitted by the X-ray machine and shot by the camera module; and

and analyzing and acquiring an image with a higher brightness value in the at least two images as the portal image.

In one embodiment, the step of analyzing and acquiring the image with the higher brightness value of the at least two images as the portal image includes:

step S1, acquiring the image and the brightness value of the current camera module;

step S2, determining whether the brightness value of the current image is greater than a preset threshold, if the brightness value of the current image is less than or equal to the preset threshold, executing step S1, and if the brightness value of the current image is greater than the preset threshold, executing step S3;

step S3, taking the current image as the image with the highest brightness value, updating the preset threshold value to the brightness value of the current image, starting a timer, and executing step S4;

step S4, determining whether the time from the first time of acquiring the image to the current image exceeds the preset timer time, if the time from the first time of acquiring the image to the current image is greater than or equal to the preset timer time, executing step S5, and if the time from the first time of acquiring the image to the current image is less than the preset timer time, executing step S1;

and step S5, outputting the image with the highest brightness value as a portal image.

In an embodiment, the step of obtaining a light field image formed by visible light emitted by an X-ray machine light field indicator lamp shot by the camera module includes: the size of the X-ray machine light field area is adjusted and projected onto the light field detection plate, the camera module shoots the light field image and receives the light field image shot by the camera module.

In one embodiment, the step of analyzing the light field image or the portal image to obtain the image attribute of the light field region or the portal region comprises:

carrying out binarization filtering on the light field image or the radiation field image;

analyzing the image after the binarization filtering to obtain a contour figure; and

and calculating a minimum circumscribed rectangular area corresponding to the outline pattern, and taking the minimum circumscribed rectangular area as the light field area or the radiation field area.

In one embodiment, the step of calculating the minimum bounding rectangle area corresponding to the outline graphics comprises:

step a1, calculating a circumscribed rectangle of the outline graph according to a direct calculation method, taking an original circumscribed rectangle of the outline graph as a minimum circumscribed rectangle RectMin, recording the length, the width and the area of the minimum circumscribed rectangle RectMin, assigning the area of the minimum circumscribed rectangle RectMin to a first variable AreaMin, and setting a rotation angle α to be 0 degree;

step a2, rotating the outline graph by theta degrees, calculating the minimum circumscribed rectangle RectTmp after the radiation field outline graph is rotated according to the step a1, and assigning the area of the minimum circumscribed rectangle RectTp to a second variable AreaTmp;

step a3, setting a rotation angle α to α + theta, comparing the sizes of the first variable AreaTmp and the second variable AreaMin, assigning the value with the smaller area to AreaMin, assigning the rotation angle α at the moment to β to α, and assigning rectangle information to a circumscribed rectangle RectMin to RectTmp;

a4, circularly executing the steps a2 and a3 until a minimum circumscribed rectangle RectMin and a rotation angle α corresponding to the minimum circumscribed rectangle RectMin are finally obtained, and

step a5, reversely rotating the minimum circumscribed rectangle RectMin calculated in step a4 by an angle β, thereby obtaining the minimum circumscribed rectangle area as the light field area or the radiation field area.

The invention further provides light field visual detection equipment, which comprises a light field image acquisition device and a control device, wherein the light field image acquisition device comprises a camera module, a light field detection plate and a light field detection plate, the camera module is used for acquiring a light field image formed by visible light emitted by an X-ray machine field indicator lamp and acquiring a light field image formed by X-rays emitted by an X-ray machine irradiating the light field detection plate, the light field image comprises an illuminated light field area, the light field image comprises a light field area, the control device analyzes the light field image, calculates the image attribute of the light field area, analyzes the light field image to acquire the image attribute of the light field area, and calculates the light field consistency parameter of the X-ray machine according to the light field area and the image attribute of the light field area, and the light field consistency parameter of the X-ray machine comprises the offset of the light field area relative to the light field area And (4) parameters.

In one embodiment, the light field detection plate is a transparent organic glass plate with cross-shaped scale lines, visible light emitted by the field indicating lamp of the X-ray machine is projected onto the light field detection plate to form the light field area, and the camera module shoots the light field detection plate to obtain the light field image; the field detection plate is an X-ray fluorescent plate, when X-rays emitted by the X-ray machine irradiate the field detection plate, the irradiated part can be excited to emit fluorescence to form a field area, and the camera module shoots the field detection plate to obtain a field image.

In one embodiment, the light field image collecting device further includes a camera module and a housing, the housing includes a box body and a cover body having an opening, the opening is used for arranging the light field detection plate, the cover body is used for installing the light field detection plate and is used for covering one side of the opening of the box body, and the camera module is accommodated in the box body and is used for shooting corresponding to the position of the opening to obtain the light field image and the light field image.

In one embodiment, the camera module comprises a sliding structure, a sliding block and a camera, the sliding structure is fixed in the box body, the camera is arranged on the sliding block, the sliding block and the sliding structure are in sliding fit to drive the camera to move, the object distance of the shot image is adjusted to ensure that the clearest image is obtained, and the sliding direction of the sliding block and the sliding structure is towards the opening or away from the opening.

In one embodiment, the box body comprises a bottom plate and a side wall connected to the periphery of the bottom plate, the camera module further comprises a fixing plate, the fixing plate is fixed on the bottom plate, and the sliding structure is fixed on the fixing plate so as to be fixed in the box body; the cover body is also pivoted with the edge of the box body, so that the field detection plate on the cover body can be selectively arranged corresponding to the opening.

In one embodiment, the sliding structure includes a sliding slot for slidably receiving the sliding block, the sliding block includes a sliding portion and connecting portions connected to two ends of the sliding portion, the two connecting portions are respectively used for being fixed to two ends of the camera, and at least a portion of the sliding portion and at least a portion of the connecting portions are slidably received in the sliding slot.

In an embodiment, the light field image capturing device further includes a communication module, and the camera is further configured to receive a control signal for shooting via the communication module and transmit the light field image and the light field image obtained by shooting to the control device.

Compared with the prior art, in the light radiation field visual detection method and the light radiation field visual detection equipment, the light radiation field consistency parameter of the X-ray machine can be calculated and output by acquiring and analyzing the light field image and the radiation field image, and compared with a film method, film development is not needed, so that the method has the advantages of less time consumption and low cost; compared with a fluorescence method, the method has the advantages of low cost, small exposure, capability of storing data, simpler detection process, small measurement error and the like; compared with a fluorescent video method, the method has the advantages of no need of manual reading, small human influence factor and the like.

In an embodiment, the offset parameter is further calculated by analyzing the light field region and the light field region, and particularly, the offset distance of each adjusting point of the light field region relative to the corresponding preset point of the light field region is calculated, so that the advantage of facilitating a user to adjust the light field of the X-ray machine according to the offset parameter is achieved.

In one embodiment, the portal area is obtained through binarization filtering and minimum rotation rectangle algorithm calculation, so that the portal area is calculated more accurately and has the effect of lower error.

Furthermore, the optical field image acquisition device can be provided with an optical field detection plate and a field detection plate, so that the camera module can respectively shoot the optical field image and the field image, and the conditions of mutual interference and difficulty in distinguishing caused by the optical field image and the field image on one detection plate can be avoided. In one embodiment, the cover body is further pivoted with the edge of the box body, so that the field detection plate on the cover body can be selectively arranged corresponding to the opening, and the camera module can conveniently shoot the field image and the light field image separately.

In one embodiment, the camera is in sliding fit with the sliding structure through the sliding block, so that the distance between the camera and the detection plate is easy and adjustable, and the camera detection device has the advantage of convenience in use.

In one embodiment, the fixing plate is used to fix the sliding structure, the slider and the camera in the case, and particularly, the fixing plate is used to cooperate with the guiding locking member and the guiding locking groove to guide sliding and fixing, thereby also having the advantages of convenient manufacture, installation and higher reliability.

In one embodiment, the camera module can communicate with and cooperate with an external control device through the communication module, and the camera module has the advantages of being simple to operate, convenient to use and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a light field vision inspection apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of the light field image capturing device shown in fig. 1.

Fig. 3 is a schematic perspective assembly structure view of the camera module of the light field image capturing device shown in fig. 2.

Fig. 4 is a perspective exploded view of the camera module shown in fig. 3.

FIG. 5 is a schematic structural diagram of a control device of the light field vision inspection apparatus shown in FIG. 1,

fig. 6 is a schematic configuration diagram of a light field detection system of the control device of the light field visual inspection apparatus shown in fig. 1.

Fig. 7 is a flowchart of a light portal vision inspection method used by the control device of the light portal vision inspection apparatus shown in fig. 1.

Fig. 8 is a flowchart of a portal image acquisition method in the light portal vision inspection method shown in fig. 7.

Fig. 9 is a light field region schematic diagram of a light field image in the light field visual inspection method shown in fig. 7.

Fig. 10 is a schematic view of the principle of calculation of the light field uniformity parameter in the light field visual inspection method shown in fig. 7.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.