CN110009678B - Orthodontic archwire bending detection method and orthodontic archwire bending detection system - Google Patents
Orthodontic archwire bending detection method and orthodontic archwire bending detection system Download PDFInfo
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Abstract
The invention provides a method and a system for detecting bending of an orthodontic archwire, which are characterized in that a reference archwire and a bent archwire are respectively arranged on an acquisition platform, and images of the reference archwire and the bent archwire are respectively acquired by an archwire optics image acquisition module; transmitting the acquired image information of the reference archwire and the bent archwire to a data analysis module, respectively carrying out quantitative analysis on the acquired image information of the reference archwire and the bent archwire by the data analysis module to obtain binary segmentation images of the reference archwire and the bent archwire, obtaining overlook curves of the reference archwire and the bent archwire, further establishing a coordinate system, and calculating position coordinates of each reference point on the overlook curves of the reference archwire and the bent archwire; and calculating the standard degree of the bent arch wire by a root mean square error method. The invention has the advantages of wide practical range, high detection accuracy, no dependence on personnel experience, strong adaptability, simple operation and strong flexibility.
Description
Technical Field
The invention relates to an orthodontic archwire bending detection method and system, and belongs to the technical field of orthodontic archwire bending.
Background
Orthodontic archwires are one of the commonly used orthodontic devices, and are mainly manufactured by bending the archwires. At present, orthodontic archwires are mainly produced in a large-scale manner through manual bending or mechanical production lines, in the two modes, the manual bending technology of an orthodontic doctor is continued for many years, and the large-scale production of the production lines is more and more, but the two bending modes are used for detecting the quality of the bent archwires, and the problems of limited detection range, unsatisfactory accuracy and low detection efficiency exist due to the fact that the quality detection of the bent archwires is dependent on manual experience.
The above-mentioned problems are to be considered and solved in the detection of the bending quality of orthodontic archwires.
Disclosure of Invention
The invention aims to provide an orthodontic archwire bending detection method and system, which solve the problems of limited detection range, non-ideal accuracy and low detection efficiency in the prior art due to the fact that the detection is dependent on manual experience judgment.
The technical scheme of the invention is as follows:
a method for detecting bending of orthodontic archwire comprises the following steps,
s1, respectively placing a reference arch wire and a bent arch wire on an acquisition platform, and respectively acquiring images of the reference arch wire and the bent arch wire through an arch-mercerization image acquisition module;
s2, transmitting the acquired image information of the reference archwire and the bent archwire to a data analysis module, respectively carrying out quantitative analysis on the acquired image information of the reference archwire and the bent archwire by the data analysis module to obtain binary segmentation images of the reference archwire and the bent archwire, obtaining overlooking curves of the reference archwire and the bent archwire, further establishing a coordinate system, and calculating position coordinates of each reference point on the overlooking curves of the reference archwire and the bent archwire;
s3, calculating the standard degree of the bent arch wire through a root mean square error method.
Further, in step S1, images of a reference archwire and a bent archwire are respectively acquired by an archwire optical image acquisition module, specifically,
s11, placing the reference archwire on an acquisition platform, enabling two ends of the reference archwire to be on a horizontal line L, respectively marking fixed points at the positions of an end point A of two reference archwires of the reference archwire, an end point B of the reference archwire and a center point C of the reference archwire, and acquiring images of the reference archwire;
s12, placing the bent arch wire on an acquisition platform, enabling the center point of the bent arch wire to be overlapped with the center point C mark of the reference arch wire, keeping the distances from the two end points of the bent arch wire to the end points A of the corresponding two reference arch wires of the reference arch wire and the end points B of the reference arch wire consistent, and acquiring images of the bent arch wire.
Further, in step S2, the data analysis module respectively performs quantitative analysis on the acquired image information of the reference archwire and the bent archwire, specifically,
s21, processing the acquired image information of the reference archwire and the bent archwire by adopting a maximum inter-class variance method to obtain binary segmentation images of the reference archwire and the bent archwire;
s22, processing binary segmentation images of the reference archwire and the bent archwire by adopting a rapid parallel image refinement algorithm, and extracting overlook curves of the reference archwire and the bent archwire;
s23, marking the positions of a center point C of the reference arch wire, an end point A of the reference arch wire and an end point B of the reference arch wire on the reference arch wire image, establishing a coordinate system, and calculating the position coordinates of each reference point on the overlook curve of the reference arch wire and the bent arch wire, wherein each reference point comprises a horizontal standard degree reference point obtained at a distance d in the horizontal direction and a vertical standard degree reference point obtained at a distance d in the vertical direction.
Further, step S21 processes the collected image information of the reference archwire and the bent archwire by using a maximum inter-class variance method to obtain binary segmentation images of the reference archwire and the bent archwire, which specifically includes:
s211, converting the obtained archwire image into a gray image;
s212, traversing all gray values of the obtained gray image, and respectively calculating an inter-class variance value between front and rear background pixel points taking the traversed current gray value as a threshold value, wherein the gray value with the maximum corresponding inter-class variance is the optimal segmentation threshold value;
s213, dividing the image by using an optimal dividing threshold, setting the gray value of the pixel points smaller than the threshold as 0, wherein the pixel points larger than the threshold belong to the archwire part, and the gray value of the pixel points is set as 1, so as to obtain a binary divided image of the archwire image;
s214, respectively executing the steps S211-S213 on the reference archwire image and the bending image to obtain corresponding binary segmentation images.
Further, step S22, the binary segmentation images of the reference archwire and the bent archwire are processed by adopting a rapid parallel image refinement algorithm, and the overlook curves of the reference archwire and the bent archwire are extracted, specifically,
s221, traversing all the pixel points which are obtained by segmentation and belong to an arch wire part, defining a current point as P1, defining eight neighborhood points which start from above the point in the clockwise direction as P2-P9, and setting the current point as 0 if the current point and the eight neighborhood points meet the following conditions at the same time;
wherein N (P1) represents the number of 1 pixel values in eight neighboring points of P1, S (P1) represents the number of times that two consecutive pixel values 0 and 1 respectively appear in the clockwise direction in the eight neighboring points of P1, and V (P) represents the pixel value of a certain point;
s222, traversing the pixel points belonging to the arch wire part again in the result of the step S221, and setting the current point to 0 if the current point and eight adjacent points meet the following conditions;
wherein N (P1) represents the number of 1 pixel values in eight neighboring points of P1, S (P1) represents the number of times that two consecutive pixel values 0 and 1 respectively appear in the clockwise direction in the eight neighboring points of P1, and V (P) represents the pixel value of a certain point;
s223, iterating the step S221 and the step S222 circularly until no new pixel point is set to be 0, and stopping iterating, thereby obtaining a final archwire curve;
s224, executing the steps S221-223 on the binary images obtained by dividing the reference archwire and the bent archwire respectively to obtain corresponding archwire curves.
Further, in step S23, the positions of the center point C of the reference arch wire, the end point A of the reference arch wire and the end point B of the reference arch wire on the reference arch wire image are marked, a coordinate system is established, and the position coordinates of each reference point on the overlook curve of the reference arch wire and the bent arch wire are calculated, specifically,
s231, manually marking the positions of a center point C of the reference arch wire, end points A of the left reference arch wire and the right reference arch wire and end points B of the reference arch wire on the reference arch wire image by an operator to obtain the position coordinates of the center point C and the end points B of the reference arch wire on the image;
s232, making a perpendicular line of a connecting line of an endpoint A of the reference arch wire and an endpoint B of the reference arch wire through a center point C of the reference arch wire, taking an intersection point of the perpendicular line and a connecting line of the endpoint A of the reference arch wire and the endpoint B of the reference arch wire as an origin, taking a connecting line of the endpoint A of the reference arch wire and the endpoint B of the reference arch wire as an x axis, and taking a perpendicular line of a connecting line of the center point C of the reference arch wire and the endpoint A of the reference arch wire and the endpoint B of the reference arch wire as a y axis, and establishing a two-dimensional reference coordinate system;
s233, taking the maximum numerical domain simultaneously available on the x axis of the reference archwire curve and the bent archwire curve, and obtaining N numerical values x in the numerical domain at a distance d rvi I=1, 2,3, N, taking it as the x-axis coordinate of the reference point, thereby obtaining N reference archwire curve point coordinates (x rvi ,y rvi ) I=1, 2,3, where, coordinates of curve points of N and N curved archwires (x rvi ,y' rvi ) I=1, 2,3,., N, as a reference point for the vertical standard;
s234, taking the maximum numerical domain simultaneously available on the y axis of the reference archwire curve and the bent archwire curve, and obtaining K numerical values y with a distance d in the range rhi I=1, 2,3, M, y-axis coordinates with which it is the reference point, because of the existence of a reference point on the left and right sides, M reference arch wire curve point coordinates (x rhi ,y rhi ) I=1, 2,3, M, curve point coordinates (x 'of M curved archwires' rvi ,y rvi ) I=1, 2,3,..m, where m= 2*K, as a reference point for the horizontal direction standard;
s235, normalizing the reference points in the vertical direction and the horizontal direction to obtain normalized reference point coordinates.
Further, in step S235, normalization processing is performed on the reference points in the vertical direction and the horizontal direction to obtain normalized reference point coordinates, specifically,
the normalized coordinates for the reference archwire reference point in the vertical direction are (x vi ,y vi ) I=1, 2,3, N, the normalized coordinate of the reference point of the bending arch wire is (x) vi ,y' vi ) I=1, 2,3, N, the coordinate conversion formula is:
wherein x is rvi And y rvi For reference of x-axis and y-axis coordinate values of the archwire reference point in the vertical direction before normalization, y' rvi For the y-axis coordinate value, x of the reference point of the bending arch wire in the vertical direction before normalization rvmax And y rvmax For all vertical direction reference archwire reference points maximum of x-axis and y-axis coordinates before normalization, x rvmin And y rvmin The minimum of the x-axis and y-axis coordinates of the archwire reference point is referenced for all pre-normalized vertical directions.
The normalized coordinates for a reference archwire reference point in the horizontal direction are (x hi ,y hi ) I=1, 2,3, M, the reference point coordinate of the bending arch wire is (x) hi ,y' hi ) I=1, 2,3, M, the coordinate conversion formula is:
wherein x is rhi And y rhi For x-axis and y-axis coordinate values of the reference point of the reference archwire for horizontal direction before normalization, x' rhi For the x-axis coordinate value, x of the reference point of the bending arch wire in the horizontal direction before normalization rhmax And y rhmax For all pre-normalized horizontal references to the maximum of x-axis and y-axis coordinates of the archwire reference point, x rhmin And y rhmin The minimum of x-axis coordinates and y-axis coordinates of all horizontal reference points before normalization.
Further, in step S3, the standard degree of the bending arch wire is calculated by a root mean square error method, specifically,
vertical standard S of bending arch wire v The calculation process is as follows:
wherein y is vi For the y-axis coordinates of the normalized vertical reference archwire reference point obtained in step S235, y' vi And N is the number of reference archwire reference points in the vertical direction for obtaining the y-axis coordinates of the reference points of the bent archwire in the vertical direction after normalization.
Standard S of bending bow wire in horizontal direction h The calculation process is as follows:
wherein x is vi For the x-axis coordinates of the reference archwire reference point in the normalized horizontal direction obtained in step S235, x' vi In order to obtain the x-axis coordinates of the reference points of the horizontally bent archwire after normalization, M is the number of the reference points of the reference archwire in the horizontal direction;
through the standard degree S in the vertical direction v And the standard degree S in the horizontal direction h The standard degree of the bent archwire is: s=s v +S h 。
An orthodontic archwire bending detection system comprises an acquisition platform, an optical image acquisition module and a data analysis module,
and (3) an acquisition platform: the device is used for respectively placing a reference arch wire and a bent arch wire and marking a horizontal line L on the acquisition platform;
an optical image acquisition module: respectively carrying out image acquisition on a reference arch wire and a bent arch wire which are placed on an acquisition platform, and respectively sending the acquired image information of the reference arch wire and the bent arch wire to a data analysis module;
and a data analysis module: by adopting the orthodontic archwire bending detection method, the image information of the reference archwire and the bent archwire, which are acquired by the optical image acquisition module, is processed to obtain the standard degree of the bent archwire.
Further, the optical image acquisition module comprises an archwire optical image acquisition device and a fixing support, the fixing support is an inverted L-shaped fixing support, one end of the fixing support is arranged on the acquisition platform, the other end of the fixing support is provided with the archwire optical image acquisition device, and the archwire optical image acquisition device is arranged above the acquisition platform.
The beneficial effects of the invention are as follows: the orthodontic archwire bending detection system and method have the advantages of wide practical range, high detection accuracy, high efficiency, no dependence on personnel experience, strong adaptability, simple operation and strong flexibility. According to the orthodontic archwire bending detection system and method, the archwire overlook curve is obtained, and the standard degree of the archwire is detected by comparing the deviation degree of the archwire to be detected and the reference archwire overlook curve. In the implementation process, as the gray level difference between the background and the archwire is larger, the separation of the background and the archwire image can be more effectively realized by using the maximum inter-class variance method; secondly, the quick parallel image refinement algorithm is used for effectively extracting the archwire skeleton line; in archwire standard calculation, the use of normalized reference point coordinates may exclude the effect of reference archwire dimensions on standard calculation, and the combination of taking into account vertical and horizontal standards also makes the calculation more accurate. Finally, compared with the traditional method of judging by personnel experience, the detection standard degree is more objective and accurate, and is beneficial to large-scale popularization and use.
Drawings
FIG. 1 is a flow chart of an orthodontic archwire bending detection method in accordance with an embodiment of the present invention;
FIG. 2 is an illustrative schematic diagram of an acquisition platform and an optical image acquisition module in an embodiment;
wherein: 1-acquisition platform, 2-archwire optical image acquisition device, 3-fixed bolster, 4-level line L, 5-reference arch wire's extreme point A, 6-reference arch wire's central point C, 7-reference arch wire's extreme point B, 8-reference arch wire, 9-curved system arch wire.
Detailed Description
Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Examples
An orthodontic archwire bending detection method, as shown in figure 1, comprises the following steps,
s1, respectively placing a reference arch wire 8 and a bent arch wire 9 on an acquisition platform 1, and respectively acquiring images of the reference arch wire 8 and the bent arch wire 9 through an arch-mercerization image acquisition module;
step S1, respectively acquiring images of a reference arch wire 8 and a bent arch wire 9 through an arch-mercerizing image acquisition module, specifically,
s11, placing the reference archwire 8 on the acquisition platform 1, enabling two ends of the reference archwire 8 to be on a horizontal line L4, respectively marking fixed points at the positions of an end point A5 of two reference archwires of the reference archwire 8, an end point B of the reference archwire 8 and a center point C6 of the reference archwire, and acquiring images of the reference archwire 8;
s12, placing the bent archwire 9 on the acquisition platform 1, enabling the center point of the bent archwire 9 to be overlapped with the mark of the center point C6 of the reference archwire, keeping the distances from the two end points of the bent archwire 9 to the end points A5 of the corresponding two reference archwires of the reference archwire 8 and the end points B of the reference archwire 8 consistent, and acquiring images of the bent archwire 9.
S2, transmitting the acquired image information of the reference archwire 8 and the bent archwire 9 to a data analysis module, respectively carrying out quantitative analysis on the acquired image information of the reference archwire 8 and the bent archwire 9 by the data analysis module to obtain binary segmentation images of the reference archwire 8 and the bent archwire 9, obtaining overlooking curves of the reference archwire 8 and the bent archwire 9, further establishing a coordinate system, and calculating position coordinates of each reference point on the overlooking curves of the reference archwire 8 and the bent archwire 9;
step S2, the data analysis module respectively carries out quantitative analysis on the acquired image information of the reference archwire 8 and the bent archwire 9, specifically,
s21, processing the acquired image information of the reference archwire 8 and the bent archwire 9 by adopting a maximum inter-class variance method to obtain binary segmentation images of the reference archwire 8 and the bent archwire 9; in particular to a special-shaped ceramic tile,
s211, converting the obtained archwire image into a gray image;
s212, traversing all gray values of the obtained gray image, and respectively calculating an inter-class variance value between front and rear background pixel points taking the traversed current gray value as a threshold value, wherein the gray value with the maximum corresponding inter-class variance is the optimal segmentation threshold value;
s213, dividing the image by using an optimal dividing threshold, setting the gray value of the pixel points smaller than the threshold as 0, wherein the pixel points larger than the threshold belong to the archwire part, and the gray value of the pixel points is set as 1, so as to obtain a binary divided image of the archwire image;
s214, respectively executing the steps S211-S213 on the reference archwire 8 image and the bending image to obtain corresponding binary segmentation images.
S22, processing binary segmentation images of the reference archwire 8 and the bent archwire 9 by adopting a rapid parallel image refinement algorithm, and extracting overlook curves of the reference archwire 8 and the bent archwire 9; in particular to a special-shaped ceramic tile,
s221, traversing all the pixel points which are obtained by segmentation and belong to an arch wire part, defining a current point as P1, defining eight neighborhood points which start from above the point in the clockwise direction as P2-P9, and setting the current point as 0 if the current point and the eight neighborhood points meet the following conditions at the same time;
wherein N (P1) represents the number of 1 pixel values in eight neighboring points of P1, S (P1) represents the number of times that two consecutive pixel values 0 and 1 respectively appear in the clockwise direction in the eight neighboring points of P1, and V (P) represents the pixel value of a certain point;
s222, traversing the pixel points belonging to the arch wire part again in the result of the step S221, and setting the current point to 0 if the current point and eight adjacent points meet the following conditions;
wherein N (P1) represents the number of 1 pixel values in eight neighboring points of P1, S (P1) represents the number of times that two consecutive pixel values 0 and 1 respectively appear in the clockwise direction in the eight neighboring points of P1, and V (P) represents the pixel value of a certain point;
s223, iterating the step S221 and the step S222 circularly until no new pixel point is set to be 0, and stopping iterating, thereby obtaining a final archwire curve;
s224, executing the steps S221-223 on the binary images obtained by dividing the reference archwire 8 and the bent archwire 9 respectively, and obtaining corresponding archwire curves.
S23, marking the positions of a center point C6 of the reference arch wire, an end point A5 of the reference arch wire and an end point B of the reference arch wire 8 on the image of the reference arch wire 8, establishing a coordinate system, and calculating the position coordinates of each reference point on the overlook curves of the reference arch wire 8 and the bent arch wire 9. In particular to a special-shaped ceramic tile,
s231, manually marking the positions of a center point C6 of the reference arch wire, end points A5 of the left reference arch wire and the right reference arch wire and end points B of the reference arch wire 8 on the reference arch wire image by an operator to obtain the position coordinates of the center point C6 and the end points B on the image;
s232, making a perpendicular line of a connecting line between an end point A5 of the reference arch wire and an end point B of the reference arch wire 8 through a center point C6 of the reference arch wire 8, taking an intersection point of the perpendicular line and the connecting line between the end point A5 of the reference arch wire and the end point B of the reference arch wire 8 as an origin, taking the connecting line between the end point A5 of the reference arch wire and the end point B of the reference arch wire 8 as an x-axis, and taking a perpendicular line between the center point C6 of the reference arch wire 8 and the connecting line between the end point A5 of the reference arch wire and the end point B of the reference arch wire 8 as a y-axis, and establishing a two-dimensional reference coordinate system;
s233, taking the maximum numerical domain simultaneously available on the x axis by referring to the curve of the arch wire 8 and the curve of the bent arch wire 9, and obtaining N numerical values x in the numerical domain at a distance d rvi I=1, 2,3, N, taking it as the x-axis coordinate of the reference point, thereby obtaining the coordinates (x) of the curve points of the N reference archwires 8 rvi ,y rvi ) I=1, 2,3, where, coordinates (x) of the curve points of N and N curved archwires 9 rvi ,y' rvi ) I=1, 2,3,., N, as a reference point for the vertical standard;
s234, taking the maximum numerical range simultaneously taken by the curve of the reference arch wire 8 and the curve of the bent arch wire 9 on the y axis, and obtaining K numerical values y with a distance d in the range rhi I=1, 2,3, M, y-axis coordinates with which it is the reference point, because of the existence of a reference point on the left and right sides, M reference archwire 8 curve point coordinates (x rhi ,y rhi ) I=1, 2,3, M, coordinates of 9 curve points of M bending archwires(x' rvi ,y rvi ) I=1, 2,3,..m, where m= 2*K, as a reference point for the horizontal direction standard.
S235, normalizing the reference points in the vertical direction and the horizontal direction to obtain normalized reference point coordinates.
The coordinates normalized for the reference archwire 8 reference point in the vertical direction are (x vi ,y vi ) I=1, 2,3, N, the normalized coordinates of the reference point of the bending arch wire 9 are (x) vi ,y' vi ) I=1, 2,3, N, the coordinate conversion formula is:
wherein x is rvi And y rvi For the x-axis and y-axis coordinate values of the reference point of the reference archwire 8 for the vertical direction before normalization, y' rvi For the y-axis coordinate value, x of the reference point of the bending arch wire 9 in the vertical direction before normalization rvmax And y rvmax For all vertical direction reference archwire 8 reference points maximum of x-axis and y-axis coordinates before normalization, x rvmin And y rvmin The minimum of the x-axis and y-axis coordinates of the reference point of the archwire 8 is referenced for all pre-normalized vertical directions.
The coordinates normalized for the reference archwire 8 reference point in the horizontal direction are (x hi ,y hi ) I=1, 2,3, M, the coordinates of the reference point of the bending arch wire 9 are (x) hi ,y' hi ) I=1, 2,3, M, the coordinate conversion formula is:
wherein x is rhi And y rhi For x-axis and y-axis coordinate values of the reference point of the reference archwire 8 in the horizontal direction before normalization, x' rhi For the x-axis coordinate value, x of the reference point of the horizontal bending arch wire 9 before normalization rhmax And y rhmax Reference is made to the x-axis and y-axis coordinates of the reference point of the archwire 8 for all horizontal directions before normalizationMaximum value, x rhmin And y rhmin The minimum of x-axis coordinates and y-axis coordinates of all horizontal reference points before normalization.
S3, calculating the standard degree of the bent arch wire 9 through a root mean square error method. In particular to a special-shaped ceramic tile,
standard S of the vertical direction of the bent archwire 9 v The calculation process is as follows:
wherein y is vi For the y-axis coordinates of the reference point of the reference archwire 8 in the normalized vertical direction obtained in step S235, y' vi For the obtained y-axis coordinates of the reference points of the bent archwire 9 in the vertical direction after normalization, N is the number of the reference points of the reference archwire 8 in the vertical direction.
Standard S of the horizontal direction of the bent archwire 9 h The calculation process is as follows:
wherein x is vi For the x-axis coordinates of the reference point of the reference archwire 8 in the normalized horizontal direction obtained in step S235, x' vi For the obtained x-axis coordinates of the reference points of the horizontally bent archwire 9 after normalization, M is the number of the reference points of the reference archwire 8 in the horizontal direction.
Through the standard degree S in the vertical direction v And the standard degree S in the horizontal direction h The standard degree of the bent archwire 9 is: s=s v +S h 。
An orthodontic archwire bending detection system comprises an acquisition platform 1, an optical image acquisition module and a data analysis module,
acquisition platform 1: for respectively placing a reference arch wire 8 and a bent arch wire 9 and marking a horizontal line L4 on the acquisition platform 1;
an optical image acquisition module: respectively carrying out image acquisition on a reference arch wire 8 and a bent arch wire 9 which are placed on the acquisition platform 1, and respectively sending the acquired image information of the reference arch wire 8 and the bent arch wire 9 to a data analysis module;
and a data analysis module: by adopting the orthodontic archwire bending detection method, the image information of the reference archwire 8 and the bent archwire 9 acquired by the optical image acquisition module is processed to obtain the standard degree of the bent archwire 9.
In an embodiment, as shown in fig. 2, the optical image acquisition module includes an arching-mercerizing image acquisition device 2 and a fixing support 3, the fixing support 3 is an inverted-L-shaped fixing support 3, one end of the fixing support 3 is arranged on the acquisition platform 1, the other end of the fixing support 3 is provided with the arching-mercerizing image acquisition device 2, and the arching-mercerizing image acquisition device 2 is arranged above the acquisition platform 1. The optical image acquisition module of the embodiment has simple structure and convenient use, and is convenient for image acquisition.
In the embodiment, the design of the archwire optical image collector 2 considers the size of a common archwire and the error range requirement for archwire evaluation, and adopts a camera with resolution of 2048x1536 and shooting range of 0.8-1.4 m. The resolution and the shooting range can be adjusted according to the needs to adapt to the requirements of different types of archwires
The orthodontic archwire bending detection system and method have the advantages of wide practical range, high detection accuracy, high efficiency, no dependence on personnel experience, strong adaptability, simple operation and strong flexibility. According to the orthodontic archwire bending detection system and method, the archwire overlook curve is obtained, and the standard degree of the archwire is detected by comparing the deviation degree of the archwire to be detected and the reference archwire overlook curve. In the implementation process, as the gray level difference between the background and the archwire is larger, the separation of the background and the archwire image can be more effectively realized by using the maximum inter-class variance method; secondly, the quick parallel image refinement algorithm is used for effectively extracting the archwire skeleton line; in archwire standard calculation, the use of normalized reference point coordinates may exclude the effect of reference archwire dimensions on standard calculation, and the combination of taking into account vertical and horizontal standards also makes the calculation more accurate. Finally, compared with the traditional method of judging by personnel experience, the detection standard degree is more objective and accurate, and is beneficial to large-scale popularization and use.
Claims (8)
1. A method for detecting bending of an orthodontic archwire is characterized by comprising the following steps: comprises the steps of,
s1, respectively placing a reference arch wire and a bent arch wire on an acquisition platform, and respectively acquiring images of the reference arch wire and the bent arch wire through an arch-mercerization image acquisition module;
s2, transmitting the acquired image information of the reference archwire and the bent archwire to a data analysis module, respectively carrying out quantitative analysis on the acquired image information of the reference archwire and the bent archwire by the data analysis module to obtain binary segmentation images of the reference archwire and the bent archwire, obtaining overlooking curves of the reference archwire and the bent archwire, further establishing a coordinate system, and calculating position coordinates of each reference point on the overlooking curves of the reference archwire and the bent archwire;
step S2, the data analysis module respectively carries out quantitative analysis on the acquired image information of the reference archwire and the bent archwire, specifically,
s21, processing the acquired image information of the reference archwire and the bent archwire by adopting a maximum inter-class variance method to obtain binary segmentation images of the reference archwire and the bent archwire;
s22, processing binary segmentation images of the reference archwire and the bent archwire by adopting a rapid parallel image refinement algorithm, and extracting overlook curves of the reference archwire and the bent archwire;
s23, marking the positions of a center point C of a reference arch wire, an end point A of the reference arch wire and an end point B of the reference arch wire on the reference arch wire image, establishing a coordinate system, and calculating each reference point on a overlook curve of the reference arch wire and the bent arch wire, wherein each reference point comprises position coordinates of a horizontal standard degree reference point obtained at a distance d in the horizontal direction and a vertical standard degree reference point obtained at a distance d in the vertical direction;
step S21, processing the acquired image information of the reference archwire and the bent archwire by adopting a maximum inter-class variance method to obtain binary segmentation images of the reference archwire and the bent archwire, specifically,
s211, converting the obtained archwire image into a gray image;
s212, traversing all gray values of the obtained gray image, and respectively calculating an inter-class variance value between front and rear background pixel points taking the traversed current gray value as a threshold value, wherein the gray value with the maximum corresponding inter-class variance is the optimal segmentation threshold value;
s213, dividing the image by using an optimal dividing threshold, setting the gray value of the pixel points smaller than the threshold as 0, wherein the pixel points larger than the threshold belong to the archwire part, and the gray value of the pixel points is set as 1, so as to obtain a binary divided image of the archwire image;
s214, respectively executing the steps S211-S213 on the reference archwire image and the bending image to obtain corresponding binary segmentation images;
s3, calculating the standard degree of the bent arch wire through a root mean square error method.
2. The orthodontic archwire bending detection method of claim 1, wherein: step S1, respectively acquiring images of a reference arch wire and a bent arch wire through an arch-mercerizing image acquisition module, specifically,
s11, placing the reference archwire on an acquisition platform, enabling two ends of the reference archwire to be on a horizontal line L, respectively marking fixed points at the positions of an end point A of two reference archwires of the reference archwire, an end point B of the reference archwire and a center point C of the reference archwire, and acquiring images of the reference archwire;
s12, placing the bent arch wire on an acquisition platform, enabling the center point of the bent arch wire to be overlapped with the center point C mark of the reference arch wire, keeping the distances from the two end points of the bent arch wire to the end points A of the corresponding two reference arch wires of the reference arch wire and the end points B of the reference arch wire consistent, and acquiring images of the bent arch wire.
3. The orthodontic archwire bending detection method of claim 1, wherein: s22, processing binary segmentation images of the reference archwire and the bent archwire by adopting a rapid parallel image refinement algorithm, extracting overlook curves of the reference archwire and the bent archwire, specifically,
s221, traversing all the pixel points which are obtained by segmentation and belong to an arch wire part, defining a current point as P1, defining eight neighborhood points which start from above the point in the clockwise direction as P2-P9, and setting the current point as 0 if the current point and the eight neighborhood points meet the following conditions at the same time;
wherein N (P1) represents the number of 1 pixel values in eight neighboring points of P1, S (P1) represents the number of times that two consecutive pixel values 0 and 1 respectively appear in the clockwise direction in the eight neighboring points of P1, and V (P) represents the pixel value of a certain point;
s222, traversing the pixel points belonging to the arch wire part again in the result of the step S221, and setting the current point to 0 if the current point and eight adjacent points meet the following conditions;
wherein N (P1) represents the number of 1 pixel values in eight neighboring points of P1, S (P1) represents the number of times that two consecutive pixel values 0 and 1 respectively appear in the clockwise direction in the eight neighboring points of P1, and V (P) represents the pixel value of a certain point;
s223, iterating the step S221 and the step S222 circularly until no new pixel point is set to be 0, and stopping iterating, thereby obtaining a final archwire curve;
s224, executing the steps S221-223 on the binary images obtained by dividing the reference archwire and the bent archwire respectively to obtain corresponding archwire curves.
4. The orthodontic archwire bending detection method of claim 3, wherein: step S23, marking the positions of a center point C of the reference arch wire, an end point A of the reference arch wire and an end point B of the reference arch wire on the reference arch wire image, establishing a coordinate system, calculating the position coordinates of each reference point on the overlook curve of the reference arch wire and the bent arch wire, specifically,
s231, manually marking the positions of a center point C of the reference arch wire, end points A of the left reference arch wire and the right reference arch wire and end points B of the reference arch wire on the reference arch wire image by an operator to obtain the position coordinates of the center point C and the end points B of the reference arch wire on the image;
s232, making a perpendicular line of a connecting line of an endpoint A of the reference arch wire and an endpoint B of the reference arch wire through a center point C of the reference arch wire, taking an intersection point of the perpendicular line and a connecting line of the endpoint A of the reference arch wire and the endpoint B of the reference arch wire as an origin, taking a connecting line of the endpoint A of the reference arch wire and the endpoint B of the reference arch wire as an x axis, and taking a perpendicular line of a connecting line of the center point C of the reference arch wire and the endpoint A of the reference arch wire and the endpoint B of the reference arch wire as a y axis, and establishing a two-dimensional reference coordinate system;
s233, taking the maximum numerical domain simultaneously available on the x axis of the reference archwire curve and the bent archwire curve, and obtaining N numerical values x in the numerical domain at a distance d rvi I=1, 2,3, N, taking it as the x-axis coordinate of the reference point, thereby obtaining N reference archwire curve point coordinates (x rvi ,y rvi ) I=1, 2,3, where, coordinates of curve points of N and N curved archwires (x rvi ,y' rvi ) I=1, 2,3,., N, as a reference point for the vertical standard;
s234, taking the maximum numerical domain simultaneously available on the y axis of the reference archwire curve and the bent archwire curve, and obtaining K numerical values y in the numerical domain at a distance d rhi I=1, 2,3, M, y-axis coordinates with which it is the reference point, because of the existence of a reference point on the left and right sides, M reference arch wire curve point coordinates (x rhi ,y rhi ) I=1, 2,3, M, curve point coordinates (x 'of M curved archwires' rvi ,y rvi ) I=1, 2,3,..m, where m= 2*K, as a reference point for the horizontal direction standard;
s235, normalizing the reference points in the vertical direction and the horizontal direction to obtain normalized reference point coordinates.
5. The orthodontic archwire bending detection method of claim 4, wherein: in step S235, normalization processing is performed on the reference points in the vertical direction and the horizontal direction to obtain normalized reference point coordinates, specifically,
the normalized coordinates for the reference archwire reference point in the vertical direction are (x vi ,y vi ) I=1, 2,3, N, the normalized coordinate of the reference point of the bending arch wire is (x) vi ,y' vi ) I=1, 2,3, N, the coordinate conversion formula is:
wherein x is rvi And y rvi For reference of x-axis and y-axis coordinate values of the archwire reference point in the vertical direction before normalization, y' rvi For the y-axis coordinate value, x of the reference point of the bending arch wire in the vertical direction before normalization rvmax And y rvmax For all vertical direction reference archwire reference points maximum of x-axis and y-axis coordinates before normalization, x rvmin And y rvmin Referencing the minimum values of the x-axis coordinates and the y-axis coordinates of the archwire reference points for all vertical directions before normalization;
the normalized coordinates for a reference archwire reference point in the horizontal direction are (x hi ,y hi ) I=1, 2,3, M, the reference point coordinate of the bending arch wire is (x) hi ,y' hi ) I=1, 2,3, M, the coordinate conversion formula is:
wherein x is rhi And y rhi For x-axis and y-axis coordinate values of the reference point of the reference archwire for horizontal direction before normalization, x' rhi For the x-axis coordinate value, x of the reference point of the bending arch wire in the horizontal direction before normalization rhmax And y rhmax For all pre-normalized horizontal references to the maximum of x-axis and y-axis coordinates of the archwire reference point, x rhmin And y rhmin The minimum of x-axis coordinates and y-axis coordinates of all horizontal reference points before normalization.
6. The orthodontic archwire bending detection method of claim 5, wherein: step S3, calculating the standard degree of the bent arch wire by a root mean square error method, wherein the standard degree is specifically as follows:
vertical standard S of bending arch wire v The calculation process is as follows:
wherein y is vi Y 'for the normalized vertical direction reference archwire reference point obtained in step S235' vi In order to obtain the y-axis coordinates of the reference points of the bent archwire in the vertical direction after normalization, N is the number of the reference points of the reference archwire in the vertical direction;
standard S of bending bow wire in horizontal direction h The calculation process is as follows:
wherein x is vi For the x-axis coordinates, x 'of the normalized horizontal direction reference archwire reference point obtained in step S234' vi In order to obtain the x-axis coordinates of the reference points of the horizontally bent archwire after normalization, M is the number of the reference points of the horizontally reference archwire;
through the standard degree S in the vertical direction v And the standard degree S in the horizontal direction h The standard degree of the bent archwire is: s=s v +S h 。
7. An orthodontic archwire bending detection system is characterized in that: comprises an acquisition platform, an optical image acquisition module and a data analysis module,
and (3) an acquisition platform: the device is used for respectively placing a reference arch wire and a bent arch wire and marking a horizontal line L on the acquisition platform;
an optical image acquisition module: respectively carrying out image acquisition on a reference arch wire and a bent arch wire which are placed on an acquisition platform, and respectively sending the acquired image information of the reference arch wire and the bent arch wire to a data analysis module;
and a data analysis module: the method for detecting the bending of the orthodontic archwire according to any one of claims 1 to 6 is used for processing the image information of the reference archwire and the bending archwire acquired by the optical image acquisition module to obtain the standard degree of the bending archwire.
8. The orthodontic archwire bending detection system of claim 7, wherein: the optical image acquisition module comprises an archwire optical image acquisition device and a fixing support, wherein the fixing support is an inverted L-shaped fixing support, one end of the fixing support is arranged on the acquisition platform, the other end of the fixing support is provided with the archwire optical image acquisition device, and the archwire optical image acquisition device is arranged above the acquisition platform.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106803276A (en) * | 2017-01-16 | 2017-06-06 | 哈尔滨理工大学 | A kind of personalized orthodontic bow-wire curve interactive regulation method |
| CN107714203A (en) * | 2017-11-14 | 2018-02-23 | 哈尔滨理工大学 | A kind of orthodontic bow-wire angularly divided bends sequential program(me) method |
| CN109269407A (en) * | 2018-09-28 | 2019-01-25 | 中铁工程装备集团有限公司 | A kind of vertical shaft laser guide localization method based on labview |
-
2019
- 2019-04-11 CN CN201910291868.4A patent/CN110009678B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106803276A (en) * | 2017-01-16 | 2017-06-06 | 哈尔滨理工大学 | A kind of personalized orthodontic bow-wire curve interactive regulation method |
| CN107714203A (en) * | 2017-11-14 | 2018-02-23 | 哈尔滨理工大学 | A kind of orthodontic bow-wire angularly divided bends sequential program(me) method |
| CN109269407A (en) * | 2018-09-28 | 2019-01-25 | 中铁工程装备集团有限公司 | A kind of vertical shaft laser guide localization method based on labview |
Non-Patent Citations (1)
| Title |
|---|
| 口腔正畸力模拟及牙齿移动调制研究;李再金;《中国优秀硕士学位论文全文数据库 医药卫生科技辑》;20160315(第03期);全文 * |
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