CN115704669B - A catheter length measurement method for digital production - Google Patents
A catheter length measurement method for digital productionInfo
- Publication number
- CN115704669B CN115704669B CN202110937550.6A CN202110937550A CN115704669B CN 115704669 B CN115704669 B CN 115704669B CN 202110937550 A CN202110937550 A CN 202110937550A CN 115704669 B CN115704669 B CN 115704669B
- Authority
- CN
- China
- Prior art keywords
- catheter
- camera
- edge
- pixel
- length
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention discloses a catheter length measurement method for digital production, which comprises the following steps that a photoelectric sensor synchronously triggers two industrial cameras to acquire end images of a catheter, the real edge of the catheter is obtained through the methods of region-of-interest extraction, catheter edge identification, discontinuous edge complementation, backlight source edge elimination, environmental noise elimination and the like, then the right catheter elliptical edge profile is obtained through elliptical edge rough extraction and fine extraction, roundness is analyzed, a central point of the end face of the catheter is found, and finally the catheter inclination angle correction is carried out according to the slope of the straight line section profile, and the length data of the catheter is calculated and obtained by combining system calibration parameters. The invention can realize the length measurement of the catheter in the digital production process of the catheter, has high measurement speed, high automation degree, good universality and better stability.
Description
Technical Field
The invention relates to the technical field of computer vision, and discloses a catheter length measurement method for digital production.
Background
The conduit is widely applied to the manufacturing fields of aerospace, aviation, automobiles and the like, is used for transmitting working media such as gas, liquid and the like, and is an important component in an engine system. In order to adapt to a narrow space in an engine and meet the small production requirement of the engine, a guide pipe is required to be converted into a bent pipe with a complex three-dimensional posture from a straight pipe through bending processing, and the guide pipe is assembled in the engine without interference. The manufacturing precision of the bent pipe is an important factor influencing the performance of the engine, and the manufacturing precision of the bent pipe is directly determined by the production quality of the straight pipe, so that the high-quality production of the straight pipe is the basic guarantee of the high performance of the engine. Length measurement is an important link in straight pipe production and relates to the production efficiency and the manufacturing quality of an engine.
Currently, in the field of aerospace, a method for measuring the length of a catheter still stays in the traditional contact measurement, mainly a measuring method and a three-coordinate method. The measuring tool method is to use special measuring tools such as vernier calipers to clamp the end of the guide tube to obtain the length information. The method is greatly influenced by the subjective of operators, the false detection probability is high, and special detection tools with different types are required to be used for the catheters with different specifications. The three-coordinate method is to use a three-coordinate measuring machine to obtain the three-dimensional key point coordinates of the surface of the pipe, and calculate the length of the pipe through fitting analysis. The method is complex to operate, has high technical requirements on operators, and has a limited measuring range. Therefore, the existing catheter length measuring method has the advantages of higher labor cost, low automation degree and high error rate, can not meet the current digital production requirement, and can block the development of the manufacturing technology in the aerospace field from the source.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a catheter length measurement method for digital production, which utilizes a computer vision processing algorithm to realize non-contact and batch on-line catheter length measurement and can effectively improve the digital production level of the catheter.
The technical scheme adopted by the invention for realizing the purpose is that the catheter length measuring method for digital production comprises the following steps:
A catheter length measurement method for digital production, which obtains the edge contour of a catheter by shooting images of two ends of the catheter to be detected and performing image processing, calculates the actual catheter length according to the pixel distance of the catheter, specifically comprises the following steps:
S1, station detection and movement, namely when a conduit to be detected is placed at a detection station, outputting a signal by a photoelectric sensor arranged on the station to be detected, controlling an industrial camera on a slide rail to move to the position right above two ends of the conduit to be detected, and controlling a backlight source on the slide rail to move to the position below two ends of the conduit to be detected;
s2, triggering and shooting, namely synchronously triggering an industrial camera to respectively acquire left and right end images of the catheter;
S3, performing image processing on the original images at the left end part and the right end part respectively to obtain the pixel distance of the length of the catheter in the view field of the camera;
i. extracting and preprocessing a catheter edge image, and removing environmental noise to obtain a catheter sub-pixel edge;
analyzing the edge image of the catheter, and extracting the center point of the end face of the catheter;
Correcting the inclination angle of the catheter, and calculating the length pixel distance of the catheter in the visual field of the camera;
and S4, calculating the length of the conduit, namely calculating the actual length of the conduit according to the pixel distance of the length of the conduit in the vision fields of the left camera and the right camera and by combining the camera distance and the camera pixel size parameter obtained by the calibration of the system.
The extracting and preprocessing of the catheter edge image comprises the following steps:
s3.1, intercepting a rectangular area in an image as an interested area according to a fixed position of the end face of the catheter under the view angle of a camera;
S3.2, extracting sub-pixel edges of the region of interest by using a canny operator, and complementing adjacent and discontinuous edges;
S3.3, setting a difference threshold value of a maximum value and a minimum value of the row coordinates of the edges of the sub-pixels, and eliminating the edge outline of the backlight source;
And S3.4, reserving the sub-pixel edge with the largest contour length as a conduit edge, and eliminating other environmental noise.
Analyzing the catheter edge image, extracting the catheter end face center point includes:
S3.5, dividing the edge profile of the catheter into a plurality of straight line segments and elliptical arc segments, and combining the elliptical edge profiles with adjacent end points and discontinuous end points into an elliptical edge profile;
S3.6, if the number of the combined elliptical edge contours is greater than 1, selecting an elliptical edge contour with the smallest pixel column coordinate mean value as a left end surface ellipse of the catheter for a left image, and selecting an elliptical edge contour with the largest pixel column coordinate mean value as a right end surface ellipse of the catheter for a right image, wherein the image coordinate systems under the left and right camera view angles both take the lower left corner of the image as a coordinate origin;
s3.7, calculating the roundness of the elliptical edge profile, if the roundness is greater than 0.008, fitting the roundness into an ellipse through least squares, selecting an ellipse center point as a catheter end face center point, and otherwise, calculating the centroid of the elliptical edge profile as the catheter end face center point.
The correcting the catheter inclination angle, calculating the catheter pixel distance in the camera view field comprises:
S3.8, selecting two lines with the largest length in the straight line section outline, fitting straight lines, and calculating the average value of slopes of the two lines to respectively obtain that the slope of the straight line section of the conduit under the view angle of the left camera is k l and the slope of the straight line section of the conduit under the view angle of the right camera is k r;
S3.9, setting the actual inclination angle of the catheter in the view of the left camera as theta l, setting the column pixel coordinate of the center point of the end face as y l, setting the column pixel resolution of the camera as y, and calculating the pixel distance d l on the left side of the catheter as:
kl＝tanθl
dl＝(y-yl)/cosθl
Let the actual dip angle of the catheter in the right camera view be θ r, the column pixel coordinate of the center point of the catheter end face be y r, the mean value of the slope of the fitting straight line be k r, and the pixel distance d r on the right side of the catheter be calculated as:
kr＝tanθr
dr＝yr/cosθr
The calculating the catheter length includes:
Based on the catheter pixel distances d l and d r in the two camera views, the system calibrates the resulting camera distance Δl and camera pixel size δ, and the actual length l of the catheter can be calculated as:
l=(dl+dr)·δ+Δl
The camera distance delta l and the camera pixel size delta are obtained through pre-calibration.
The catheter length measuring device for digital production comprises a device body and an upper computer, wherein the upper computer outputs instructions to shoot images of two ends of a catheter to be detected, performs image processing to obtain the edge profile of the catheter, and calculates the actual catheter length according to the pixel distance of the catheter;
The device body comprises a metal frame, four electric guide rails, a guide pipe station support frame, two backlight source support frames, two backlight sources, a photoelectric sensor, two vertical electric sliding tables and two industrial cameras;
the upper computer comprises a processor and a memory, wherein a station detection and movement program module, a trigger shooting program module, an image processing program module and a catheter length calculation program module are stored in the memory, and the processor loads the program modules to execute the method steps to realize the catheter length measurement of digital production.
The bottom beam of the metal frame is provided with a guide pipe station support frame, two sides of the guide pipe station support frame are respectively provided with an electric guide rail, two ends of each electric guide rail are fixedly connected with the bottom beam of the metal frame, a backlight source is arranged at the top of the backlight source support frame and is respectively connected with the two electric guide rails in a sliding manner through a sliding block, and a photoelectric sensor is arranged at the top of the guide pipe station support frame and is used for sensing whether the guide pipe to be detected is placed on the guide pipe station support frame or not;
two electric guide rails are arranged on the top cross beam of the metal frame, two ends of each electric guide rail are fixedly connected with the top cross beam of the metal frame, two vertical electric sliding tables are respectively connected with the two electric guide rails in a sliding manner through sliding blocks, and two industrial cameras are respectively and fixedly arranged below the vertical electric sliding tables; two electric guide rails, a vertical electric sliding table and an industrial camera on the top cross beam of the metal frame are respectively connected with an upper computer to receive instructions of the upper computer.
The program steps of the station detection and movement program module specifically comprise:
When the conduit to be detected is placed on the conduit station supporting frame, the photoelectric sensor outputs induction signals to the upper computer, and the upper computer controls the bottom cross beam of the metal frame and the four electric guide rails on the top cross beam to horizontally slide and the vertical electric sliding table to vertically slide, so that the backlight light source is driven to move below two ends of the conduit to be detected, the industrial cameras are driven to move above the two ends of the conduit to be detected, and meanwhile, the two industrial cameras start to respectively shoot left and right images of the two ends of the conduit and send the left and right images to the upper computer.
In the moving process, the distance between the two industrial cameras is unchanged, and the distance from the industrial camera to the axis of the guide pipe is ensured to be unchanged when the industrial camera is moved by the vertical electric sliding table.
The invention has the following beneficial effects and advantages:
1. the method provides a novel length measurement method for catheter digital production, has the advantages of non-contact, high efficiency, good robustness and the like, and is beneficial to promoting the improvement of the manufacturing level in the aerospace field in China.
2. The invention accurately extracts the center of the end face of the catheter by two times of ellipse edge extraction and ellipse fitting, improves the stability of the catheter measuring method, has strong universality and can be suitable for catheters with any specification.
3. The method has short measurement time and high automation degree, can complete continuous on-line measurement of the catheter, can be used as a unit in a catheter digital production system, and greatly improves the production efficiency and the manufacturing quality of the catheter.
Drawings
FIG. 1 is a schematic view of a catheter length measuring device body in the method of the present invention;
FIG. 2 is a schematic diagram of the internal modules of the upper computer in the method of the present invention;
FIG. 3 is a flow chart of the method of the present invention;
FIG. 4 is a flow chart of an image processing algorithm in the method of the present invention;
FIG. 5 (a) is an image of the region of interest of the catheter tip under the left camera in the method of the invention;
FIG. 5 (b) is an edge image of the region of interest image of the catheter tip under the left camera after subpixel extraction and complementation in the method of the present invention;
FIG. 5 (c) is an edge image of the original image of the catheter tip under the left camera after preprocessing and extraction in the method of the present invention;
FIG. 6 (a) is an edge image of a duct edge image under a left camera divided by a straight line segment and an elliptical arc segment in the method of the present invention;
fig. 6 (b) is an edge image of a catheter edge image under a left camera after elliptical edge rough extraction in the method of the present invention;
FIG. 6 (c) is an image of the center point of the end face of the left camera after ellipse fitting of the edge image of the catheter;
FIG. 7 (a) is a schematic diagram of the inclination correction of the catheter under the left camera in the method of the present invention;
FIG. 7 (b) is a schematic diagram of the inclination correction of the catheter under the right camera in the method of the present invention;
FIG. 8 (a) is a view of the center point image of the end surface of the catheter as finally processed by the left camera in the method of the present invention;
FIG. 8 (b) is a view of the center point image of the end surface of the catheter as finally processed by the right camera in the method of the present invention;
Wherein 1 is a device body, 101 is a metal frame, 102 is an electric guide rail, 103 is a catheter station support frame, 104 is a backlight source support frame, 105 is a backlight source, 106 is a photoelectric sensor, 107 is a vertical electric sliding table, 108 is an industrial camera, 2 is an upper computer, 201 is a processor, 202 memory, 2021 station detection and movement program module, 2022 triggering shooting program module, 2023 image processing program module and 2024 catheter length calculation program module.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit or scope of the invention, which is therefore not limited to the specific embodiments disclosed below.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
As shown in fig. 1-2, the hardware device for measuring the length of the catheter comprises a device body 1 and an upper computer 2. The device body 1 comprises a steel frame 101, four electric guide rails 102, a catheter station support 103, two backlight support frames 104, two backlight light sources 105, a photoelectric sensor 106, two vertical electric sliding tables 107 and two industrial cameras 108. The upper computer 2 comprises a processor 201 and a memory 202, wherein a station detection and movement program module 2021, a trigger shooting program module 2022, an image processing program module 2023 and a catheter length calculation program module 2024 are stored in the memory 202, and the processor 201 loads the method steps of executing program detection by the program modules to realize catheter length measurement of digital production.
Be equipped with pipe station support frame 103 on steel frame 101's the bottom crossbeam, pipe station support frame 103 both sides are equipped with an electronic guide rail 102 respectively, the both ends of electronic guide rail 102 and steel frame 101's bottom crossbeam rigid coupling, backlight support 104 is through slider and two electronic guide rail 102 sliding connection respectively, backlight support 104 top is equipped with backlight 105, backlight 105 is the LED backlight, pipe station support frame 103 top is equipped with photoelectric sensor 106, when waiting to detect the pipe is placed on pipe station support frame 103, wait to detect the pipe both ends and hang on backlight 105, photoelectric sensor 106 is used for responding to and waiting to detect whether the pipe is placed on pipe station support frame 103. Two electric guide rails 102 and a photoelectric sensor 106 on the bottom beam of the steel frame 101 are respectively connected with an upper computer to receive instructions of the upper computer.
Two electric guide rails 102 are arranged on the top cross beam of the steel frame 101, two ends of each electric guide rail 102 are fixedly connected with the top cross beam of the steel frame 101, a vertical electric sliding table 107 is respectively connected with the two electric guide rails 102 in a sliding mode through sliding blocks, and an industrial camera 108 is fixedly arranged at the lower portion of the vertical electric sliding table 107. Two electric guide rails 102, a vertical electric sliding table 107 and an industrial camera 108 on the top cross beam of the steel frame 101 are respectively connected with an upper computer to receive instructions of the upper computer.
When the conduit to be detected is placed on the conduit station supporting frame 103, the photoelectric sensor 106 outputs induction signals to the upper computer, and the upper computer controls the four electric guide rails 102 on the bottom beam and the top beam of the steel frame 101 to slide horizontally and the four electric sliding tables 107 to slide vertically, so that the backlight light source 105 is driven to move below two ends of the conduit to be detected, the industrial cameras 108 are driven to move above two ends of the conduit to be detected, and meanwhile, the two industrial cameras 108 start to respectively shoot left and right images of two ends of the conduit and send the left and right images to the upper computer. In the moving process, the distance between the two industrial cameras 108 is unchanged, and the distance from the industrial camera 108 to the axis of the guide pipe is required to be kept unchanged when the industrial camera 108 is moved by the vertical electric sliding table 107.
As shown in fig. 3 to 4, the catheter length measurement method for digital production of the invention comprises the following steps:
Step1, in the digital production process of the catheter, the processed catheter is sent into a length measuring unit and placed on a supporting frame 103;
step 2, synchronously triggering two industrial cameras 108 by a photoelectric sensor 106 below the catheter, and collecting end images of the catheter;
Step 3, processing the image acquired by the left camera in the following steps 4.1 to 4.9 to obtain the pixel distance of the catheter in the view field of the camera;
i. extracting catheter edge images and preprocessing (steps 3.1-3.4):
Step 3.1, a fixed rectangular area is cut out from an original image to serve as an interested area, an inherent ineffective background area in the image is removed, the interested area shown in (a) of fig. 5 is obtained, and the end of the catheter is placed at a fixed position of an industrial camera view angle range each time, so that the fixed area is cut out to serve as the interested area of the end of the catheter.
3.2, Extracting sub-pixel edges of the region of interest by using a canny operator, complementing adjacent and discontinuous edges of end points, and ensuring continuity of the edges of the guide pipes, wherein the extracted sub-pixel edges comprise edges of backlight light sources, real edges of the guide pipes, some environmental noise points and small edges in the figure as shown in (b) of figure 5;
And 3.3, calculating the maximum value and the minimum value of the pixel row coordinates of each object in the edges of the sub-pixels, calculating the difference value of the maximum value and the minimum value, and eliminating the edge objects with the difference value smaller than the threshold value, namely eliminating the edge contour of the backlight light source. In the experiment, the threshold was set to 1075;
Step 3.4, comparing the contour lengths of all edges obtained in the step 3.3, wherein the contour length of the noise edge is smaller than that of the edge of the conduit, and selecting the edge with the largest contour length as the real edge of the conduit, so that some environmental noise points and small edges can be removed, as shown in (c) of fig. 5;
Analyzing the edge image of the catheter, and extracting the center point of the end face of the catheter (step 3.5-3.7):
Step 3.5, as shown in (a) of fig. 6, dividing the edge profile of the catheter into a plurality of straight line segments and elliptical arc segments by a straight line segment progressive approximation profile method, combining the straight line profiles used in the subsequent steps, using the slope fitting in step 4.8, combining the elliptical arc segments, combining elliptical edge profiles with adjacent and discontinuous endpoints, filtering the straight line segment profiles, and completing the rough extraction of the elliptical edge;
And 3.6, if the number of the oval edge contours obtained by the rough extraction is larger than 1 as shown in (b) of fig. 6, the oval edge contour object obtained by the rough extraction is traversed, the contour with the minimum pixel column coordinate mean value (the image coordinate system under the left and right camera view angles takes the left lower corner of the image as the origin of coordinates) is reserved, if the image acquired by the right camera is reserved, the contour with the maximum pixel column coordinate mean value is reserved, the oval edge contour can be removed, the fine extraction is completed, and if not, the next step is directly carried out.
Step 3.7, calculating the roundness of the elliptical edge profile, if the roundness is greater than 0.008, fitting the roundness into an ellipse through least square, and taking the center point of the ellipse as the center point of the end surface of the catheter, otherwise, calculating the centroid of the elliptical edge profile as the center point of the end surface of the catheter;
Correcting the inclination angle of the catheter, and calculating the length pixel distance of the catheter in the visual field of the camera (step 3.8-3.9):
Step 3.8, sorting the straight line contours obtained in the step 4.5 from large to small according to the length, taking the first two straight line contours, calculating the average value of the slopes of the two straight lines through straight line fitting, and setting the average value as k l;
Step 3.9 as shown in fig. 7 (a), assuming that the actual inclination angle of the catheter in the view of the left camera is θ l, the column pixel coordinate of the center point of the end face is y l, the column pixel resolution of the camera is y, and the corrected catheter length pixel distance d l can be calculated as:
kl＝tanθl (1)
dl＝(y-yl)/cosθl (2)
Step4, as shown in fig. 7 (b), the image acquired by the right camera is processed in steps 3.1 to 3.8, the actual inclination angle of the catheter in the view of the left camera is set to be θ r, the column pixel coordinate of the center point of the end face is set to be y r, the average value of the slope of the fitting straight line is set to be k r, and the corrected catheter length pixel distance d r can be calculated as:
kr＝tanθr (3)
dr＝yr/cosθr (4)
Step 5, according to the pixel distances d l and d r of the length of the catheter in the two camera fields of view, the camera distance Deltal and the camera pixel size delta obtained by system calibration can be calculated as the actual length l of the catheter:
l=(dl+dr)·δ+Δl (5)
before the measurement unit is initialized, the calibration of the system is completed, and the method comprises the following steps:
Two stainless steel bars with good axial straightness, good end flatness and small length difference are manufactured, and the lengths of the two standard tubes are measured by using a three-coordinate measuring machine as standard tubes, and are assumed to be l 1 and l 2. The two standard pipes are respectively measured by the method of the invention, so that all industrial cameras and backlight light sources are kept motionless during the two measurements, and the left and right ends of the two standard pipes are in the visual field of the two cameras.
Assuming that the pixel distances d l1 and d r1 in the left and right camera views after the standard tube with the length l 1 is measured, and the pixel distances d l2 and d r2 in the left and right camera views after the standard tube with the length l 2 is measured, the following relationship exists between the camera distance Δl and the pixel size δ:
l1＝(dl1+dr1)·δ+Δl (4)
l2＝(dl2+dr2)·δ+Δl (5)
and after calculation and solution, the parameter calibration of the system is completed.
And 6, after the current catheter length measurement is completed, waiting for the next catheter to be processed and sending the catheter to a length measurement unit.
Fig. 8 (a) is a center point image of the end face of the catheter finally processed under the left camera in the method of the present invention, and fig. 8 (b) is a center point image of the end face of the catheter finally processed under the right camera in the method of the present invention, the diameter of the catheter is 10mm, the measurement length is 814.961mm, and the single measurement time is 1.5s.
In summary, the method provided by the invention is used for measuring the length of the catheter for digital production, and has the advantages of high measuring speed, high degree of automation, high stability and great improvement on the production efficiency and the manufacturing quality of the catheter.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the invention thereto, but to limit the invention thereto, and any modifications, equivalents, and so on, falling within the spirit and principles of the invention.
Claims (6)
1. The catheter length measurement method for digital production is characterized by comprising the following steps of capturing images of two ends of a catheter to be detected, performing image processing to obtain an edge profile of the catheter, and calculating the actual catheter length according to the pixel distance of the catheter:
S1, station detection and movement, namely when a conduit to be detected is placed at a detection station, outputting a signal by a photoelectric sensor (106) arranged on the station to be detected, controlling an industrial camera (108) on a slide rail to move to the position right above two ends of the conduit to be detected, and controlling a backlight source (105) on the slide rail to move to the position below two ends of the conduit to be detected;
s2, triggering a shooting step, namely synchronously triggering an industrial camera (108) to respectively acquire left and right end images of the catheter;
S3, performing image processing on the original images at the left end part and the right end part respectively to obtain the pixel distance of the length of the catheter in the view field of the camera;
i. extracting and preprocessing a catheter edge image, and removing environmental noise to obtain a catheter sub-pixel edge;
Analyzing the edge image of the catheter to extract the center point of the end face of the catheter, comprising:
S3.5, dividing the edge profile of the catheter into a plurality of straight line segments and elliptical arc segments, and combining the elliptical edge profiles with adjacent end points and discontinuous end points into an elliptical edge profile;
S3.6, if the number of the combined elliptical edge contours is greater than 1, selecting an elliptical edge contour with the smallest pixel column coordinate mean value as a left end surface ellipse of the catheter for a left image, and selecting an elliptical edge contour with the largest pixel column coordinate mean value as a right end surface ellipse of the catheter for a right image, wherein the image coordinate systems under the left and right camera view angles both take the lower left corner of the image as a coordinate origin;
S3.7, calculating the roundness of the oval edge contour, if the roundness is greater than 0.008, fitting the oval by least squares, and selecting an oval center point as a center point of the end face of the catheter;
Correcting the inclination angle of the catheter, and calculating the length pixel distance of the catheter in the visual field of the camera; comprising the following steps:
S3.8, selecting two lines with the largest length in the straight line section outline, fitting straight lines, and calculating the average value of slopes of the two lines to respectively obtain that the slope of the straight line section of the conduit under the view angle of the left camera is k l and the slope of the straight line section of the conduit under the view angle of the right camera is k r;
S3.9, setting the actual inclination angle of the catheter in the view of the left camera as theta l, setting the column pixel coordinate of the center point of the end face as y l, setting the column pixel resolution of the camera as y, and calculating the pixel distance d l on the left side of the catheter as:
kl＝tanθl
dl＝(y-yl)/cosθl
Let the actual dip angle of the catheter in the right camera view be θ r, the column pixel coordinate of the center point of the catheter end face be y r, the mean value of the slope of the fitting straight line be k r, and the pixel distance d r on the right side of the catheter be calculated as:
kr＝tanθr
dr＝yr/cosθr
S4, calculating the length of the conduit according to the pixel distance of the length of the conduit in the vision fields of the left camera and the right camera and combining the camera distance and the camera pixel size parameter obtained by the calibration of the system, and calculating the length of the actual conduit, wherein the calculating comprises the following steps:
Based on the catheter pixel distances d l and d r in the two camera views, the system calibrates the resulting camera distance Δl and camera pixel size δ, and the actual length l of the catheter can be calculated as:
l=(dl+dr)·δ+Δl
The camera distance delta l and the camera pixel size delta are obtained through pre-calibration.
2. The method for digitally producing a catheter length measurement according to claim 1, wherein the extracting and preprocessing the catheter edge image comprises:
s3.1, intercepting a rectangular area in an image as an interested area according to a fixed position of the end face of the catheter under the view angle of a camera;
S3.2, extracting sub-pixel edges of the region of interest by using a canny operator, and complementing adjacent and discontinuous edges;
S3.3, setting a difference threshold value of a maximum value and a minimum value of the row coordinates of the edges of the sub-pixels, and eliminating the edge outline of the backlight source;
And S3.4, reserving the sub-pixel edge with the largest contour length as a conduit edge, and eliminating other environmental noise.
3. The catheter length measuring device for digital production is characterized by comprising a device body (1) and an upper computer (2), wherein the upper computer (2) outputs instructions to shoot images of two ends of a catheter to be detected, performs image processing to obtain an edge profile of the catheter, and calculates the actual catheter length according to the pixel distance of the catheter;
the device body (1) comprises a metal frame (101), four electric guide rails (102), a guide pipe station supporting frame (103), two backlight source supporting frames (104), two backlight sources (105), a photoelectric sensor (106), two vertical electric sliding tables (107) and two industrial cameras (108);
The upper computer (2) comprises a processor (201) and a memory (202), wherein a station detection and movement program module (2021), a trigger shooting program module (2022), an image processing program module (2023) and a catheter length calculation program module (2024) are stored in the memory (202), and the processor (201) loads the program modules to execute the steps of the method according to any one of claims 1-2 so as to realize digitally produced catheter length measurement.
4. The catheter length measurement device for digital production according to claim 3, wherein a catheter station support frame (103) is arranged on a bottom cross beam of the metal frame (101), two electric guide rails (102) are respectively arranged on two sides of the catheter station support frame (103), two ends of each electric guide rail (102) are fixedly connected with the bottom cross beam of the metal frame (101), a backlight support (104) is respectively connected with the two electric guide rails (102) in a sliding manner through a sliding block, a backlight light source (105) is arranged at the top of the backlight support (104), a photoelectric sensor (106) is arranged at the top of the catheter station support frame (103), when a catheter to be detected is placed on the catheter station support frame (103), two ends of the catheter to be detected are suspended on the backlight light source (105), and the photoelectric sensor (106) is used for sensing whether the catheter to be detected is placed on the catheter station support frame (103), and the two electric guide rails (102) and the photoelectric sensor (106) on the bottom cross beam of the metal frame (101) are respectively connected with an upper computer (2) to receive instructions of the upper computer;
Two electric guide rails (102) are arranged on the top cross beam of the metal frame (101), two ends of each electric guide rail (102) are fixedly connected with the top cross beam of the metal frame (101), two vertical electric sliding tables (107) are respectively connected with the two electric guide rails (102) in a sliding mode through sliding blocks, two industrial cameras (108) are respectively and fixedly arranged below the vertical electric sliding tables (107), and the two electric guide rails (102), the vertical electric sliding tables (107) and the industrial cameras (108) on the top cross beam of the metal frame (101) are respectively connected with an upper computer (2) to receive instructions of the upper computer.
5. The digitally-produced catheter length measurement device of claim 4 wherein the process steps of the station detection and movement process module (2021) specifically include:
When a catheter to be detected is placed on the catheter station support frame (103), the photoelectric sensor (106) outputs induction signals to the upper computer (2), the upper computer (2) controls the bottom cross beam of the metal frame (101) and the four electric guide rails (102) on the top cross beam to horizontally slide and the vertical electric sliding table (107) to vertically slide, so that the backlight light source (105) is driven to move below two ends of the catheter to be detected, the industrial camera (108) is driven to move above two ends of the catheter to be detected, and meanwhile, the two industrial cameras (108) start to respectively shoot left and right images of two ends of the catheter and send the left and right images to the upper computer (2).
6. The digital production-oriented catheter length measuring device according to claim 5, wherein the distance between the two industrial cameras (108) is unchanged during the moving process, and the distance from the industrial camera (108) to the catheter axis is ensured to be unchanged when the industrial camera (108) is moved by the vertical electric sliding table (107).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110937550.6A CN115704669B (en) | 2021-08-16 | 2021-08-16 | A catheter length measurement method for digital production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110937550.6A CN115704669B (en) | 2021-08-16 | 2021-08-16 | A catheter length measurement method for digital production |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115704669A CN115704669A (en) | 2023-02-17 |
| CN115704669B true CN115704669B (en) | 2025-08-26 |
Family
ID=85180338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110937550.6A Active CN115704669B (en) | 2021-08-16 | 2021-08-16 | A catheter length measurement method for digital production |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115704669B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119268553A (en) * | 2024-12-11 | 2025-01-07 | 赫比（上海）自动化科技有限公司 | Automated multi-angle product inspection equipment and inspection method |
| CN120063130B (en) * | 2025-04-29 | 2025-09-05 | 承德建龙特殊钢有限公司 | Capillary length determination method, device, electronic device and storage medium |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110766669A (en) * | 2019-10-18 | 2020-02-07 | 南京大学 | Pipeline measuring method based on multi-view vision |
| CN111047702A (en) * | 2019-12-18 | 2020-04-21 | 成都飞机工业（集团）有限责任公司 | Automatic welding method for flange bent pipe based on binocular vision |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6950546B2 (en) * | 2002-12-03 | 2005-09-27 | Og Technologies, Inc. | Apparatus and method for detecting surface defects on a workpiece such as a rolled/drawn metal bar |
| CN112729150B (en) * | 2019-10-14 | 2021-10-22 | 中国科学院沈阳自动化研究所 | Measuring method of catheter under robot grip |
-
2021
- 2021-08-16 CN CN202110937550.6A patent/CN115704669B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110766669A (en) * | 2019-10-18 | 2020-02-07 | 南京大学 | Pipeline measuring method based on multi-view vision |
| CN111047702A (en) * | 2019-12-18 | 2020-04-21 | 成都飞机工业（集团）有限责任公司 | Automatic welding method for flange bent pipe based on binocular vision |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115704669A (en) | 2023-02-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109612390B (en) | Large-size workpiece automatic measuring system based on machine vision | |
| CN111207695A (en) | Hot-rolled strip steel end three-dimensional contour measuring method based on double-line structured light | |
| CN109060836B (en) | Machine vision-based high-pressure oil pipe joint external thread detection method | |
| CN105783723B (en) | Precision die surface processing accuracy detection device and method based on machine vision | |
| CN101559512B (en) | Welding track detection and control method of plate butt weld based on laser ranging | |
| CN104315978B (en) | A kind of measuring method and device of pipeline end face center point | |
| CN102589516B (en) | Dynamic distance measuring system based on binocular line scan cameras | |
| CN106197612B (en) | A liquid level detection method for transparent bottles based on machine vision | |
| CN102778196A (en) | Image size measuring method based on laser calibration | |
| CN110926378A (en) | An improved bar straightness detection system and method based on visual inspection | |
| CN107817044B (en) | Device and method for measuring plate vibration based on machine vision | |
| CN113551619B (en) | On-line measuring method and device for straightness of seamless steel pipe | |
| CN115704669B (en) | A catheter length measurement method for digital production | |
| CN107703513B (en) | Non-contact net relative position detection method based on image processing | |
| CN105184792B (en) | A kind of saw blade wear extent On-line Measuring Method | |
| CN113532328B (en) | A system and method for real-time measurement of surface profile in the straightening process of medium and thick plates | |
| CN111047588A (en) | A Graphical Measurement Method for Dimension of Small Shaft Parts | |
| CN113607058B (en) | A method and system for dimension detection of straight-edge knives based on machine vision | |
| CN110763136A (en) | A high-precision three-dimensional workpiece size detection system and method | |
| CN115641326B (en) | Sub-pixel size detection method and system for ceramic antenna PIN needle image | |
| CN109300125A (en) | An algorithm for extracting pantograph skateboard images of urban rail trains in complex environments | |
| CN110064680A (en) | A kind of bar macrobending deformation method for fast measuring | |
| CN118816749A (en) | A method and device for evaluating workpiece contour based on machine vision | |
| CN108180825A (en) | A kind of identification of cuboid object dimensional and localization method based on line-structured light | |
| CN120970548A (en) | A method and system for measuring the surface flatness of a medium-thick plate using single-line laser. |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |