In-situ Measurement Method for Exit Area of Aeroengine Tail Nozzle

Abstract

The present invention discloses a method for on-site measurement of the outlet area of an aero-engine tail nozzle, comprising the following steps: formulating a reference template; arranging the reference template at the outlet of the aero-engine tail nozzle so that the reference template matches the cross-section of the aero-engine tail nozzle outlet; obtaining an image to be analyzed based on a camera facing the outlet of the aero-engine tail nozzle; extracting a first area corresponding to the reference template and a second area corresponding to the aero-engine tail nozzle outlet from the image to be analyzed, obtaining a first imaging pixel area corresponding to the first area, and obtaining a second imaging pixel area corresponding to the second area; and obtaining the area of the aero-engine tail nozzle outlet. The present invention can effectively ensure the measurement accuracy by comparing and measuring with a standard template. The present invention is simple to operate, flexible to use, highly adaptable to the on-site environment, high in measurement efficiency, capable of direct on-site measurement, and conducive to the analysis and verification of the test performance data of aero-engines.

Description

Technical Field

[0001] The present invention belongs to the technical field of in-situ measurement of the exit area of an aero-engine nozzle, and particularly relates to a method for in-situ measurement of the exit area of an aero-engine nozzle. Background Art

[0002] In order to obtain accurate test run performance data, an aero-engine needs to carry out in-situ measurement of the cold state area of the nozzle exit on a test bench. Specifically, for the core engine test piece of a civil aero-engine, it is necessary to perform in-situ measurement of the cold state area of the process nozzle exit; for the whole machine test piece of a civil aero-engine, it is necessary to perform in-situ measurement of the cold state area of the process nozzle exit and the cold state area of the process outer bypass exit.

[0003] Due to the large volume of the engine, complex working conditions at the test bench site, and large fluctuations in ambient temperature and humidity, conventional high-precision coordinate measuring machines are difficult to adapt to on-site measurement tasks. Currently, for the measurement of the cold state area of the process nozzle on the test bench for the core engine test piece, first, the distance between the inner surface of the process nozzle and the surface perpendicular to the tail cone is measured in-situ using a vernier caliper, and then combined with the nozzle exit radius and tail cone angle measured by a coordinate measuring machine in the single-piece state before the assembly of the nozzle assembly, and then substituted into the nozzle exit area formula for measurement and calculation. The measurement process has high requirements for the operation of the caliper, is inconvenient to observe, and the part states before and after assembly are likely to change, resulting in size changes. Therefore, it is difficult for the nozzle exit area calculated by directly using the size measurement value in the single-piece state to reflect the true value after assembly.

[0004] Due to advantages such as non-contact, high measurement efficiency, and large measurement point density, the three-dimensional scanning measurement method based on binocular stereo vision has begun to be applied in the measurement of the cold state nozzle (inner and outer bypass) area of the whole aero-engine. This method is based on the binocular stereo vision principle of the triangulation method, which requires at least two images to be collected from different perspectives to complete the three-dimensional coordinate measurement of spatial points. In addition, to ensure measurement accuracy, the measurement method based on binocular stereo vision often needs to calibrate the internal and external parameters of the two cameras before use. On a complex and narrow test bench, it is difficult for the same measured feature to be synchronously visible from two different perspectives at the same time, resulting in time-consuming and laborious adjustment of the measurement perspective of the binocular stereo vision measurement method in the measurement of the cold state nozzle area of the whole aero-engine, and low measurement efficiency.

[0005] The problem that the nozzle exit area calculated by directly using the single-piece size measurement value before assembly due to incomplete on-site dimensions is inconsistent with the actual true exit area. The problem that it is difficult to adjust the measurement perspective of the binocular stereo vision measurement method when measuring the engine tail nozzle area under complex working conditions. The problem of low measurement efficiency in the current binocular stereo vision measurement process, where multiple images need to be taken. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defect that it is difficult to adjust the measurement angle of view in the binocular stereo vision measurement method in the prior art, and to provide an in-situ measurement method for the outlet area of an aero-engine tail nozzle.

[0007] The present invention solves the above technical problem through the following technical solutions:

[0008] The present invention provides an in-situ measurement method for the outlet area of an aero-engine tail nozzle, including the following steps:

[0009] S1. Formulate a reference template, the shape of the reference template matches the shape of the outlet of the aero-engine tail nozzle, the coverage range of the reference template is smaller than the corresponding range of the outlet of the aero-engine tail nozzle, and obtain the first area S of the reference template;

[0010] S2. Set the reference template at the outlet of the aero-engine tail nozzle so that the reference template matches the cross-section of the outlet of the aero-engine tail nozzle;

[0011] S3. Obtain an image to be analyzed based on a camera facing the outlet of the aero-engine tail nozzle, and the image to be analyzed includes the reference template and the outlet of the aero-engine tail nozzle;

[0012] S4. Extract the first area corresponding to the reference template and the second area corresponding to the outlet of the aero-engine tail nozzle from the image to be analyzed, obtain the first imaging pixel area S P of the first area, and obtain the second imaging pixel area A P of the second area;

[0013] S5. Obtain the area A of the outlet of the aero-engine tail nozzle according to the first area S, the first imaging pixel area S P and the second imaging pixel area A P , where A = S * A P / S P .

[0014] Preferably, step S1 specifically includes:

[0015] Set at least one positioning mark on the reference template;

[0016] Step S3 includes:

[0017] Obtain local images corresponding to each of a plurality of preset viewpoints based on the plurality of preset viewpoints, the local images include at least one of the at least one positioning mark, and splice the local images according to the positioning marks to obtain the image to be analyzed, and the sum of the plurality of preset viewpoints covers the reference template and the outlet of the aero-engine tail nozzle.

[0018] Preferably, the reference template is annular, and each positioning mark includes at least two circular spots, and the at least two circular spots are arranged radially along the reference template.

[0019] Preferably, the number of positioning marks is several, and the several positioning marks are evenly arranged radially along the reference template.

[0020] Preferably, step S1 specifically includes:

[0021] Measuring the reference template based on a high-precision three-coordinate measuring machine to obtain the first area S.

[0022] Preferably, the number of positioning marks is several, and step S3 includes:

[0023] Generating several preset perspectives, obtaining local images based on each preset perspective in a preset order, and any two adjacent local images include at least the same positioning mark, and the adjacent local images are the local images corresponding to two adjacent preset perspectives according to the preset order.

[0024] Preferably, step S4 includes:

[0025] Performing binarization processing on the image to be analyzed to extract the first contour of the reference template in the image to be analyzed and the second contour of the outlet of the aeroengine tail nozzle in the image to be analyzed, obtaining a first area according to the first contour, and obtaining a second area according to the second contour.

[0026] Preferably, step S4 includes:

[0027] Processing the image to be analyzed based on the gray-scale sub-pixel processing algorithm to extract the first contour of the reference template in the image to be analyzed and the second contour of the outlet of the aeroengine tail nozzle in the image to be analyzed, obtaining a first area according to the first contour, and obtaining a second area according to the second contour.

[0028] Preferably, step S2 includes:

[0029] A light source is arranged on the first side of the reference template, the light of the light source faces the first side, and the range covered by the light of the light source includes the first side; the first side is the side of the reference template close to the outlet of the aeroengine tail nozzle;

[0030] Step S3 includes:

[0031] Obtaining the image to be analyzed in the state where the light source is turned on.

[0032] Preferably, step S3 includes:

[0033] Obtaining local images based on the same camera in a preset order.

[0034] The positive and progressive effects of the present invention are as follows: The present invention uses a standard template for comparison measurement, which can effectively ensure the measurement accuracy. The present invention has simple operation, flexible use, strong adaptability to the on-site environment, high measurement efficiency, and can directly measure the in-situ area of the cold nozzle outlet of a civil aeroengine on a test stand, which is beneficial for designers and process personnel to analyze and verify the test performance data of aeroengines. Moreover, the present invention can quickly complete the measurement of the engine tail nozzle area in a single field of view, greatly improving the measurement efficiency, reducing cumbersome work, and being flexible and convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FIG. is a flow chart of the method for on-site measurement of the outlet area of the aeroengine tail nozzle according to Embodiment 1 of the present invention.

[0036] Figure 2 FIG. is a schematic diagram of the reference template of the method for on-site measurement of the outlet area of the aeroengine tail nozzle according to Embodiment 1 of the present invention.

[0037] Figure 3 FIG. is a schematic diagram of the aeroengine tail nozzle of the method for on-site measurement of the outlet area of the aeroengine tail nozzle according to Embodiment 1 of the present invention.

[0038] Figure 4 FIG. is a schematic diagram of the setting mode of the camera and the aeroengine tail nozzle of the method for on-site measurement of the outlet area of the aeroengine tail nozzle according to Embodiment 1 of the present invention.

[0039] Figure 5 FIG. is a schematic diagram of the reference template of the method for on-site measurement of the outlet area of the aeroengine tail nozzle according to Embodiment 2 of the present invention.

[0040] Figure 6 FIG. is a schematic diagram of several shooting perspectives of the camera of the method for on-site measurement of the outlet area of the aeroengine tail nozzle according to Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples.

[0042] Embodiment 1

[0043] This embodiment provides a method for on-site measurement of the outlet area of an aeroengine tail nozzle. Referring to Figure 1 , the method for on-site measurement of the outlet area of the aeroengine tail nozzle includes the following steps:

[0044] Step S1, formulate a reference template and obtain the first area S of the reference template. Among them, the shape of the reference template matches the shape of the outlet of the aeroengine tail nozzle, and the coverage range of the reference template is smaller than the corresponding range of the outlet of the aeroengine tail nozzle.

[0045] Step S2: Set the reference template at the outlet of the aero-engine tail nozzle so that the reference template matches the cross-section of the aero-engine tail nozzle outlet.

[0046] Step S3: Obtain the image to be analyzed based on the camera facing the outlet of the aero-engine tail nozzle. The image to be analyzed includes the reference template and the outlet of the aero-engine tail nozzle.

[0047] Step S4: Extract the first area corresponding to the reference template and the second area corresponding to the aero-engine tail nozzle outlet from the image to be analyzed, and obtain the first imaging pixel area S corresponding to the first area P and obtain the second imaging pixel area A corresponding to the second area P .

[0048] Step S5: Obtain the area A of the aero-engine tail nozzle outlet according to the first area S, the first imaging pixel area S P and the second imaging pixel area A. Among them, A = S * A P / S P / S P .

[0049] During specific implementation, first, according to Step S1, formulate the reference template. Taking the cold-state nozzle of a certain model of civil aero-engine on the test bench as the aero-engine tail nozzle to be measured as an example, referring to Figure 2 , Figure 3 , Figure 4 , the reference template includes a first reference template 101 and a second reference template 102. Among them, the first reference template 101 matches the outer duct outlet 201 of the aero-engine tail nozzle 2, and the second reference template 102 matches the inner duct outlet 202 of the aero-engine tail nozzle 2. As an optional implementation method, according to the shapes of the outer duct outlet 201 and the inner duct outlet 202 of the aero-engine tail nozzle 2, both the first reference template 101 and the second reference template 102 are annular.

[0050] In some optional implementation methods, the reference template is made of a material with a small coefficient of thermal expansion, wear resistance, and not easy to deform, so as to ensure that the reference template is not easy to deform during use.

[0051] As an optional implementation method, in Step S1, a high-precision three-coordinate measuring machine is used to measure the reference template to obtain the area of the reference template. In other optional implementation methods, other high-precision vision measuring machines are used to measure the reference template to obtain the area of the reference template. Taking the first reference template 101 as an example, assume that the measured area is S.

[0052] Then, according to step S2, a reference template is set at the outlet of the aero-engine tail nozzle so that the reference template matches the cross-section of the outlet of the aero-engine tail nozzle. Refer to Figure 4 , the first reference template 101 is set at the outer flow outlet 201 of the aero-engine tail nozzle 2 so that the first reference template 101 matches the cross-section of the outer flow outlet 201 of the aero-engine tail nozzle 2; the second reference template 102 is set at the inner flow outlet 202 of the aero-engine tail nozzle 2 so that the second reference template 102 matches the cross-section of the inner flow outlet 202 of the aero-engine tail nozzle 2.

[0053] Next, according to step S3, a to-be-analyzed image is acquired by a camera facing the outlet of the aero-engine tail nozzle. The to-be-analyzed image includes the reference template and the outlet of the aero-engine tail nozzle. As an optional implementation manner, the camera 3 is directly opposite to the outlet of the aero-engine tail nozzle, that is, the shooting direction of the camera 3 is perpendicular to the plane where the outer flow outlet 201 of the aero-engine tail nozzle 2 is located, and the camera 3 is arranged on a straight line passing through the center of the first reference template 101 and perpendicular to the plane where the outer flow outlet 201 of the aero-engine tail nozzle 2 is located. In this way, based on one camera, taking one image can obtain the entire picture of the outlet of the aero-engine tail nozzle and the reference template, so that the area of the outlet of the aero-engine tail nozzle can be obtained based on one image. The to-be-analyzed image is acquired by the camera 3, and the to-be-analyzed image includes the outer flow outlet 201 of the aero-engine tail nozzle 2, the first reference template 101, the inner flow outlet 202 of the aero-engine tail nozzle 2, and the second reference template 102.

[0054] Then, according to step S4, a first region corresponding to the reference template and a second region corresponding to the outlet of the aero-engine tail nozzle are extracted from the to-be-analyzed image, and the first imaging pixel area S corresponding to the first region is obtained P , and the second imaging pixel area A corresponding to the second region is obtained PSpecifically, taking the outer bypass outlet 201 of the aero-engine tail nozzle 2 and the first reference template 101 as examples, in some alternative embodiments, the image to be analyzed is binarized to extract the first contour corresponding to the first reference template 101 and the second contour corresponding to the outer bypass outlet 201 of the aero-engine tail nozzle 2 in the image to be analyzed. The first area is obtained according to the first contour, and the second area is obtained according to the second contour, where the first area is the area corresponding to the first reference template 101 in the image to be analyzed, and the second area is the area corresponding to the outer bypass outlet 201 in the image to be analyzed. Binarizing the image and identifying the contour of the target area in the binarized image are technical means that can be achieved by the prior art. In some other alternative embodiments, the image to be analyzed is processed based on the grayscale sub-pixel processing algorithm to extract the first contour corresponding to the first reference template 101 and the second contour corresponding to the outer bypass outlet 201 of the aero-engine tail nozzle 2 in the image to be analyzed. The first area is obtained according to the first contour, and the second area is obtained according to the second contour. Processing the image based on the grayscale sub-pixel processing algorithm and identifying the contour of the target area in the processed image are technical means that can be achieved by the prior art.

[0055] Then, obtain the first imaging pixel area S corresponding to the first area P , and obtain the second imaging pixel area A corresponding to the second area P , where the unit of the imaging pixel area is pixel 2 , that is, square pixel. Taking a rectangular image as an example, its imaging pixel area is the product of the number of pixels contained horizontally and the number of pixels contained vertically in the rectangular image.

[0056] Next, in step S5, according to the first area S, the first imaging pixel area S P and the second imaging pixel area A P , obtain the area A of the outer bypass outlet 201 of the aero-engine tail nozzle 2, where A = S * A P / S P . Among them, the units of the first area S and the area A of the outer bypass outlet 201 are cm 2 (square centimeter). The method for obtaining the area of the inner bypass outlet 202 of the aero-engine tail nozzle 2 is similar to the method for obtaining the area of the outer bypass outlet 201 of the aero-engine tail nozzle 2, which will not be elaborated here.

[0057] The basic scheme of the in-situ measurement method for the exit area of the aero-engine tail nozzle in this embodiment is as follows: First, a standard template (i.e., a reference template) similar to the shape of the tail nozzle exit is made. The size of the made standard template is slightly smaller than the tail nozzle exit to facilitate the flexible placement of the template during measurement so that it can cooperate with the area of the cross-section of the tail nozzle to be measured. When the standard template is placed in place, an image is taken by a camera in the direction directly facing the tail nozzle exit. Then, image processing is performed on the taken picture to extract the image contours of the engine tail nozzle exit cross-section and the standard template, and calculate the pixel areas of the engine tail nozzle exit cross-section and the standard template in the image. Finally, the area of the measured cross-section of the nozzle is calculated based on the product of the ratio of the pixel areas of the two and the reference value of the area of the standard template.

[0058] As a method for in-situ measurement of the exit area of the aero-engine tail nozzle using monocular vision, the in-situ measurement method for the exit area of the aero-engine tail nozzle in this embodiment only needs to take one image to achieve a single measurement within a single field of view, without the need to take multiple images. It has a simple structure, a small volume, is flexible to use on-site, and has a high measurement efficiency. Moreover, this method is based on the standard template comparison measurement method, utilizes the camera imaging mapping principle, establishes a functional relationship between the area of the measured nozzle exit and the area of the high-precision standard template, and realizes rapid measurement. Further, compared with the traditional binocular or multiocular vision measurement system, this method does not require prior calibration and has a high adaptability to the measurement of complex working conditions.

[0059] Embodiment 2

[0060] Based on the in-situ measurement method for the exit area of the aero-engine tail nozzle in Embodiment 1 of this example, this embodiment provides an in-situ measurement method for the exit area of the aero-engine tail nozzle.

[0061] In this embodiment, referring to Figure 5 , positioning marks 103 are provided on the reference template. In some optional embodiments, the number of the positioning marks 103 is several, and several positioning marks 103 are evenly arranged along the radial direction of the reference template. Among them, each positioning mark 103 includes at least two circular spots, and at least two circular spots are arranged along the radial direction of the reference template. Taking Figure 5 as an example, the number of the positioning marks 103 provided on the first reference template 101 is 8, and each positioning mark 103 includes two circular spots.

[0062] In specific implementation, in step S3, a plurality of preset perspectives are generated, local images corresponding to each preset perspective are obtained based on the plurality of preset perspectives, the local images include at least one of at least one positioning mark, and the local images are stitched according to the positioning marks to obtain an image to be analyzed. The sum of the plurality of preset perspectives covers the reference template and the outlet of the aero-engine tail nozzle. In an alternative implementation, local images are obtained based on each preset perspective in a preset order, and any two adjacent local images include at least the same positioning mark. The adjacent local images are the local images corresponding to two preset perspectives adjacent according to the preset order.

[0063] When one perspective of the camera cannot completely cover the entire measurement section of the engine tail nozzle outlet, the entire tail nozzle outlet section can be divided into several sub-regions for separate shooting. To improve efficiency, the number of divided sub-regions should be as small as possible. When shooting and measuring in sub-regions, the shooting should be completed in sequence according to a certain order. When shooting separately, for each sub-region, the shooting orientation of the camera should be adjusted separately to obtain the most ideal imaging effect. Figure 6 A schematic is provided, which shows 4 shooting perspectives, namely the first perspective P1, the second perspective P2, the third perspective P3, and the fourth perspective P4.

[0064] To facilitate the matching and association of the local images taken of each sub-region during subsequent processing, the marked circular spots on the standard template can be used as the association and matching features. For shooting and measuring from multiple perspectives, to facilitate the subsequent stitching of images, the above-mentioned marked points can be used to associate and match the images taken under two adjacent perspectives. To ensure the integrity of the measurement data, when shooting, the smallest divided sector ring should be completely covered under a single perspective, and a certain margin should be left.

[0065] In an alternative implementation, the local images are stitched according to the positioning marks to obtain an image to be analyzed, and then the area of the aero-engine tail nozzle outlet is obtained based on the image to be analyzed.

[0066] As an alternative implementation, the area of the outer duct outlet 201 wherein, represents the imaging pixel area of the local part of the outer duct outlet 201 corresponding to the i-th perspective; represents the imaging pixel area of the local part of the first reference template 101 corresponding to the i-th perspective; n represents the total number of divided local parts, and the n local parts are stitched to form the complete outer duct outlet 201 and the first reference template 101. The method for obtaining the area of the inner duct outlet 202 of the aero-engine tail nozzle 2 is similar to the method for obtaining the area of the outer duct outlet 201 of the aero-engine tail nozzle 2, and will not be elaborated here.

[0067] The in-situ measurement method for the outlet area of the aero-engine tail nozzle according to this embodiment only requires one camera, and its viewing angle is relatively less restricted by the on-site working conditions. This method only needs one camera to take an image to quickly complete the measurement of the outlet area of the engine tail nozzle, greatly improving the measurement efficiency. Moreover, it is small in size, convenient and flexible to use, simple to operate, highly adaptable to the on-site environment, and has high measurement efficiency. Compared with the traditional binocular or multi-camera vision measurement system, this method does not require prior calibration and has high adaptability to the measurement of complex working conditions.

[0068] Embodiment 3

[0069] Based on Embodiment 1 or Embodiment 2, this embodiment provides an in-situ measurement method for the outlet area of the aero-engine tail nozzle.

[0070] In this embodiment, in step S2, a light source is arranged on the first side of the reference template, the light of the light source faces the first side, and the range covered by the light of the light source includes the first side. The first side is the side of the reference template close to the outlet of the aero-engine tail nozzle. Correspondingly, in step S3, the image to be analyzed is acquired in the state where the light source is turned on.

[0071] In this embodiment, to enhance the signal-to-noise ratio, taking advantage of the fact that the reference template is similar in shape to the cross-section to be measured at the nozzle but slightly smaller in size (i.e., the covered range), a light source is arranged on the back (the first side) of the reference template. By taking backlight photos, the signal-to-noise ratio of the contour of the outlet cross-section of the aero-engine tail nozzle and the contour of the reference template can be improved, thereby improving the accuracy of obtaining the contour and further improving the accuracy of obtaining the outlet area of the aero-engine tail nozzle.

[0072] Although the specific implementation manners of the present invention have been described above, those skilled in the art should understand that this is only for illustration purposes. The protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for on-site measurement of the exit area of an aero-engine tail nozzle, characterized in that, It includes the following steps: S1. Formulate a reference template, the shape of the reference template matches the shape of the outlet of the aero-engine tail nozzle, the coverage range of the reference template is smaller than the corresponding range of the outlet of the aero-engine tail nozzle, and obtain the first area S of the reference template; S2. Set the reference template at the outlet of the aero-engine tail nozzle so that the reference template matches the cross-section of the outlet of the aero-engine tail nozzle; S3. Obtain an image to be analyzed based on a camera facing the outlet of the aero-engine tail nozzle, and the image to be analyzed includes the reference template and the outlet of the aero-engine tail nozzle; S4. Extract the first region corresponding to the reference template and the second region corresponding to the outlet of the aero-engine tail nozzle from the image to be analyzed, and obtain the first imaging pixel area S corresponding to the first region p , and obtain the second imaging pixel area A corresponding to the second region p ; S5. According to the first area S, the first imaging pixel area S p and the second imaging pixel area A p obtain the area A of the outlet of the aero-engine tail nozzle, where A = S * A p / S p .

2. The in-situ measurement method for the outlet area of the aero-engine tail nozzle according to claim 1, characterized in that Step S1 specifically includes: Set at least one positioning mark on the reference template; Step S3 includes: Obtain local images corresponding to each of the preset viewpoints based on a plurality of preset viewpoints, each local image includes at least one of the at least one positioning mark, and splice the local images according to the positioning marks to obtain the image to be analyzed, and the sum of the plurality of preset viewpoints covers the reference template and the outlet of the aero-engine tail nozzle.

3. The in-situ measurement method for the exit area of the aero-engine tail nozzle according to claim 2, characterized in that The reference template is annular, each positioning mark includes at least two circular spots, and at least two circular spots are arranged radially along the reference template.

4. The in-situ measurement method for the outlet area of an aeroengine tail nozzle according to claim 3, wherein The number of the positioning marks is several, and several positioning marks are evenly arranged radially along the reference template.

5. The in-situ measurement method for the outlet area of the aero-engine tail nozzle according to claim 1, characterized in that Step S1 specifically includes: Measure the reference template based on a high-precision three-coordinate measuring machine to obtain the first area S.

6. The in-situ measurement method for the outlet area of the aero-engine tail nozzle according to claim 2, characterized in that The number of the positioning marks is several, and step S3 includes: Generate several preset viewpoints, obtain the local images based on each preset viewpoint in a preset order, any two adjacent local images include at least the same positioning mark, and the adjacent local images are the local images corresponding to two adjacent preset viewpoints according to the preset order.

7. The in-situ measurement method for the outlet area of the aero-engine tail nozzle according to claim 1, characterized in that, Step S4 includes: Perform binarization processing on the image to be analyzed to extract the first contour of the reference template in the image to be analyzed and the second contour of the outlet of the aero-engine tail nozzle in the image to be analyzed, obtain the first region according to the first contour, and obtain the second region according to the second contour.

8. The in-situ measurement method for the outlet area of the aero-engine tail nozzle according to claim 1, characterized in that Step S4 includes: Process the image to be analyzed based on the gray-scale sub-pixel processing algorithm to extract the first contour of the reference template in the image to be analyzed and the second contour of the outlet of the aero-engine tail nozzle in the image to be analyzed, obtain the first region according to the first contour, and obtain the second region according to the second contour.

9. The in-situ measurement method for the outlet area of an aero-engine tail nozzle according to claim 1, characterized in that, Step S2 includes: Set a light source on the first side of the reference template, the light of the light source faces the first side, and the range covered by the light of the light source includes the first side; the first side is the side of the reference template close to the outlet of the aero-engine tail nozzle; Step S3 includes: Obtain the image to be analyzed in the state where the light source is turned on.

10. The in-situ measurement method for the outlet area of the aero-engine tail nozzle according to claim 6, characterized in that Step S3 includes: Obtain the local images based on the same camera in the preset order.

Images