Cylindrical inner surface detection device and detection method thereof

Abstract

The invention discloses a cylindrical inner surface detection device and a detection method thereof. The cylindrical inner surface detection device comprises: a bracket, on which a support seat is provided, and the height of the support seat is adjustable; a camera, which is arranged on the bracket and located above the support seat; a detection system, which is connected to the camera; an imaging component, which comprises a reflector seat and a conical reflector, and the conical reflector is arranged on the reflector seat and located below the support seat; wherein the optical center line of the camera, the central axis of the support seat and the cone central axis of the conical reflector completely coincide with each other; compared with the prior art, the cylindrical inner surface detection device of the invention uses the conical reflector to image the cylindrical inner surface on the conical reflector, so as to facilitate observation and detection of the situation of the cylindrical inner surface; the image of the cylindrical inner surface to be detected formed in the conical reflector is photographed by the camera and transmitted to the detection system; after the detection system optimizes the image, the abnormal situation of the cylindrical inner surface can be checked by analyzing the information of the image of the cylindrical inner surface to be detected.

Description

Technical Field

[0001] The present invention relates to the field of machine vision technology, and in particular to a cylindrical inner surface detection device and a detection method thereof. Background Art

[0002] The commonly used methods for detecting the inside of the cylindrical surface in the market are human eye observation detection, mechanical probe detection, prefabricated mold penetration detection, and mechanical rotating mirror reflection detection. Human eye observation detection is the most traditional method, that is, the inspector rotates the inspected part to observe its surface condition; mechanical probe detection is to use precision detection instruments and equipment for detection, that is, to extend the detection probe into the specified position through a mechanical device to detect the inside of the cylindrical surface; prefabricated mold penetration detection is to prefabricate a cylindrical rod that matches the inside of the cylinder of the inspected part, and the inspected part is penetrated with it, and the inspection result is judged according to the penetration condition. This method only performs qualitative detection, and each size of cylindrical rod can only detect a corresponding size of cylinder; mechanical rotating mirror reflection detection is to install the reflector on the rotating shaft, and move the rotating shaft along the axis of the cylinder of the inspected part, so as to complete the detection of the inside of the cylindrical surface. Traditional mirror reflection inspection of the cylindrical surface will cause distortion, and the mechanical transmission mechanism will cause errors and wear. Summary of the invention

[0003] The purpose of the present invention is to solve the problems existing in the prior art and to provide a cylindrical inner surface detection device and a detection method thereof.

[0004] A cylindrical inner surface detection device, comprising:

[0005] A bracket, on which a support seat is provided, and the support seat has a height;

[0006] A camera is mounted on the bracket and located above the support seat;

[0007] A detection system connected to the camera;

[0008] An imaging assembly, comprising a reflector seat and a conical reflector, wherein the conical reflector is arranged on the reflector seat and is located below the support seat;

[0009] Among them, the optical center line of the camera, the central axis of the object holder and the central axis of the cone of the conical reflector completely coincide with each other; the inner surface of the cylinder to be detected is imaged in the conical reflector, and the camera takes a picture of the image of the cylinder to be detected in the conical reflector and transmits it to the detection system, which collects data on the image of the inner surface of the cylinder to be detected and compares and analyzes it with the data of the inner surface of the cylinder to be detected.

[0010] According to one embodiment of the present invention, the field of view radius of the camera is set to F, and the angle between any mirror surface of the conical reflector and the central axis of the cone of the conical reflector is α; if the inner surface height of the cylinder to be detected is H, the inner surface radius of the cylinder to be detected is R, and the thickness of the circular ring formed by the image of the inner surface of the cylinder to be detected in the conical reflector and photographed by the camera / the radius of the circular surface is r, then r=2Hcosα≤F≤R, where 45°<α<90°.

[0011] According to one embodiment of the present invention, when r=F, the image of the inner surface of the cylinder to be detected formed on the conical reflector is a circular surface, and the radius of the circular surface is r, r=2Hcosα.

[0012] According to one embodiment of the present invention, when r<F, the image of the inner surface of the cylinder to be detected formed on the conical reflector is a ring, the outer radius of the ring is F, the thickness of the ring is r, r=2Hcosα, and the inner radius of the ring is Fr.

[0013] According to one embodiment of the present invention, the diameter of the circular surface where the top of the conical reflector is located is smaller than the inner radius of the cylinder to be detected.

[0014] A method for detecting the inner surface of a cylinder using a cylinder inner surface detection device comprises the following steps:

[0015] Place the cylinder to be tested on the support;

[0016] Adjust the conical reflector so that the optical center line of the camera, the cylinder to be detected and the center axis of the conical reflector are completely coincident;

[0017] Adjust the height of the support so that the entire inner surface of the cylinder to be detected is imaged in the conical reflector, and the image of the inner surface of the cylinder to be detected in the conical reflector is a ring or a circular surface;

[0018] Adjust the camera's field of view so that it just covers the image of the inner surface of the cylinder to be inspected formed in the conical reflector;

[0019] The camera takes a picture of the image of the inner surface of the cylinder to be inspected formed in the conical reflector;

[0020] The camera transmits the captured images to the detection system;

[0021] The detection system analyzes the images captured by the camera.

[0022] According to one embodiment of the present invention, placing the cylinder to be detected in front of the support seat also includes the following steps:

[0023] Input the height H and radius R of the inner surface of the cylinder to be inspected into the inspection system;

[0024] According to the data of the height H and radius R of the inner surface of the cylinder, the detection system unfolds the inner surface of the cylinder to be detected to produce the first rectangle. The length of the first rectangle is 2πR and the height is H. Taking one of the vertices P0 of the first rectangle as the origin, the coordinates of any point P on the first rectangle are Among them, 0°≤n≤360°, 0≤b≤1.

[0025] According to one embodiment of the present invention, the detection system analyzes the image captured by the camera including the following steps:

[0026] The detection system analyzes the parameters of the obtained picture based on the picture taken by the camera;

[0027] The detection system generates a second rectangle based on the data of the camera's field of view radius F and the thickness r of the image taken by the camera;

[0028] Take the point corresponding to P0 on the second rectangle and the first rectangle as the origin P0', take the length of the arc between any point P' and point P0' on the image as the horizontal coordinate value, and the horizontal coordinates of the points on the radius line segment of the ring / circular surface where point P' is located are all the arc lengths between P' and point P0'; set the distance between the point on the radius line segment and the point (center of the circle) on the inner circle of the ring as the vertical coordinate value, and the coordinates of any point P' on the second rectangle are

[0029] The detection system detects information of any point within the second rectangle.

[0030] According to one embodiment of the present invention, the detection system analyzes the image captured by the camera further comprising the following steps:

[0031] The detection system matches the points in the second rectangle with the points on the first rectangle one by one, obtains the surface information of the first rectangle, and further obtains the information of the inner surface of the cylinder.

[0032] Compared with the prior art, the cylindrical inner surface detection device and the detection method of the present invention have the following advantages:

[0033] The cylindrical inner surface detection device of the present invention uses a conical reflector to image the inner surface of the cylinder on the conical reflector, which is convenient for observing and detecting the condition of the inner surface of the cylinder; the image formed by the inner surface of the cylinder to be detected in the conical reflector is photographed and data is collected by a camera and transmitted to the detection system. After the detection system optimizes the image, it can check whether there are stains on the inner surface of the cylinder and whether there are any abnormalities on the surface by analyzing the information of the image of the inner surface of the cylinder to be detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a cylindrical inner surface detection device of the present invention;

[0035] Figure 2 This is a schematic diagram of the imaging relationship of the cylinder to be detected;

[0036] Figure 3 It is a schematic diagram when the image of the cylinder to be detected is formed as a ring in the conical reflector;

[0037] Figure 4 It is a schematic diagram of the case where the image of the cylinder to be detected is formed as a circular surface in the conical reflector;

[0038] Figure 5 A schematic diagram of the corresponding relationship between a first rectangle expanded from the inner surface of a cylinder and a second rectangle expanded from the ring photographed by a camera;

[0039] In the figure, 1. bracket, 11. support seat, 2. camera, 3. reflector seat, 4. conical reflector, 5. cylinder to be detected. The realization and advantages of the functions of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0040] The following will disclose multiple embodiments of the present invention with drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary. In addition, for the purpose of simplifying the drawings, some conventional structures and components will be depicted in a simple schematic manner in the drawings.

[0041] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0042] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0043] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0044] See also Figure 1 , Figure 1 It is a structural schematic diagram of the cylindrical inner surface detection device of the present invention; as shown in the figure, the cylindrical inner surface detection device includes a bracket 1, a camera 2, a detection system (not shown in the figure) and an imaging component; a support seat 11 is provided on the bracket 1, and the support seat 11 is used to place the cylinder 5 to be detected. When the cylinder 5 to be detected is placed on the support seat 11, the center line of the cylinder 5 to be detected coincides with the center axis of the support seat 11, and the height of the support seat 11 on the bracket 1 is adjustable. When the cylinder 5 to be detected is placed on the support seat 11, the height of the support seat 11 on the bracket 1 can be adjusted until the entire inner surface of the cylinder 5 to be detected is imaged in the imaging component; the camera 2 is provided on the bracket 1 and is located above the support seat 11. The optical center line of the camera 2 coincides with the center line of the support seat 11. The camera 2 is used to treat The image of the inner surface of the detection cylinder 5 in the imaging component is collected and transmitted to the detection system; the detection system is connected to the camera 2, and is used to analyze and optimize the imaging information of the inner surface of the cylinder 5 to be detected according to the information output by the camera 2, and the imaging information of the inner surface of the cylinder 5 to be detected corresponds to the inner surface of the cylinder 5 to be detected; the imaging component includes a reflector seat 3 and a conical reflector 4, the conical reflector 4 is arranged on the reflector seat 3 and is located below the object holder 11, the central axis of the object holder 11 and the central axis of the cone of the conical reflector 4 are completely coincident, the conical reflector 4 is used to observe the inner surface of the cylinder 5 to be detected, and by adjusting the relative height between the conical reflector 4 and the cylinder 5 to be detected and the cone angle of the conical reflector 4, the inner surface of the cylinder 5 to be detected is completely imaged in the conical reflector 4.

[0045] In this embodiment, the field of view radius of the camera 2 is set to F, and the angle between any mirror surface of the conical reflector 4 and the central axis of the cone of the conical reflector 4 is α; if the inner surface height of the cylinder 5 to be detected is H, the inner surface radius of the cylinder 5 to be detected is R, the thickness of the circular ring formed by the inner surface of the cylinder 5 to be detected in the conical reflector 4 and photographed by the camera 2 / the radius of the circular surface is r, because the camera 2 images the inner surface of the cylinder 5 to be detected through the cylinder 5 to be detected, in order to ensure that the camera 2 only photographs the projection information of the inner surface of the cylinder 5 to be detected, F≤R; in order to ensure that the formation of the inner surface of the cylinder 5 to be detected in the conical reflector 4 is fully captured by the field of view of the camera 2, the field of view radius F≥r of the camera 2; therefore, the thickness of the circular ring or the radius r of the circular surface formed by the inner surface of the cylinder 5 to be detected in the conical reflector 4 photographed by the camera 2, the field of view radius F of the camera 2 and the radius R of the inner surface of the cylinder 5 to be detected satisfy: r≤F≤R.

[0046] like Figure 2 As shown, Figure 2Schematic diagram of the imaging relationship of the cylinder to be detected; in this embodiment, line segment L1 is the image of the inner surface of the cylinder 5 to be detected located on the same vertical line segment H in the conical reflector 4, line segment r is the thickness of the ring / radius of the circular surface when the image of the inner surface of the cylinder 5 to be detected in the conical reflector 4 is converted into a ring / circular surface when the camera 2 shoots L1, line segment L2 is the extension line of line segment H, line segment L3 is the extension line of line segment L1, line segment L2 and line segment L3 intersect at the conical reflector 4; L4 is the connection between the highest point on line segment H and the image of the conical reflector 4, and L5 is the end of L1 away from r. The connecting line of L4, L2, L3, L4, L5 forms a parallelogram, L6 is the diagonal of the parallelogram, and the line segment L7 is the perpendicular line from the end of the line segment L1 close to r to L5; according to the imaging principle, it can be known that L1=H, L2=L3=L4=L5, among which L3, L5 and L6 form an isosceles triangle, and the two base angles of the isosceles triangle are both α (α is the cone angle of the conical reflector 4), then the vertex angle of the isosceles triangle is 180°-2α, L7=L1sin(180°-2α)=Hsin(180°-2α)=rsin 2α; so it can be concluded that,

[0047] Therefore, r=2Hcosα; since L3, L5 and L6 form an isosceles triangle whose vertex angle is equal to 180°-2α, and the angle between L1 and L7 is equal to 90°-(180°-2α)=2α-90°, 45°<α<90°.

[0048] See also Figure 3 , Figure 4 , Figure 3 It is a schematic diagram when the image of the cylinder to be detected is formed as a ring in the conical reflector; Figure 4 It is a schematic diagram when the image of the cylinder to be detected is a circular surface in the conical reflector. As shown in the figure, in this embodiment, the field of view of the camera 2 covers the image formed by the inner surface of the cylinder 5 to be detected in the conical reflector 4. Regardless of whether the image of the inner surface of the cylinder 5 to be detected in the conical reflector 4 is a ring or a circular surface, the field of view radius of the camera 2 is equal to the outer ring of the image of the inner surface of the cylinder 5 to be detected in the conical reflector 4. When r=F, the image formed by the inner surface of the cylinder 5 to be detected in the conical reflector 4 is a circular surface, and the radius of the circular surface is r, r=2Hcosα; when r<F, the image formed by the inner surface of the cylinder 5 to be detected in the conical reflector 4 is a circular ring, the outer radius of the circular ring is F, the thickness of the circular ring is r, r=2Hcosα, and the inner radius of the circular ring is Fr.

[0049] Please review Figure 3 and 4As shown in the figure, in this embodiment, in order to avoid the outside of the cylinder 5 to be detected from being imaged in the conical reflector 4, the diameter of the circular surface where the top of the conical reflector 4 is located is smaller than the radius of the inner surface of the cylinder 5 to be detected; the outside of the cylinder 5 to be detected will not be imaged in the conical reflector 4, and the camera 2 can only capture the imaging information of the inner surface of the cylinder 5 to be detected in the conical reflector 4.

[0050] A method for detecting the inner surface of a cylinder using a cylinder inner surface detection device comprises the following steps:

[0051] Place the cylinder 5 to be tested on the support 11;

[0052] Adjust the conical reflector 4 so that the optical center line of the camera 2, the cylinder 5 to be detected and the central axis of the cone of the conical reflector 4 completely coincide with each other;

[0053] Adjust the height of the support 11 so that the entire inner surface of the cylinder 5 to be detected is imaged in the conical reflector 4, and the image of the inner surface of the cylinder 5 to be detected in the conical reflector 4 is a ring or a circular surface;

[0054] Adjust the field of view of the camera 2 so that the field of view of the camera 2 just covers the image of the inner surface of the cylinder 5 to be detected formed in the conical reflector 4;

[0055] The camera 2 takes a picture of the image of the inner surface of the cylinder 5 to be inspected formed in the conical reflector 4;

[0056] Camera 2 transmits the captured image to the detection system;

[0057] The detection system analyzes the image captured by camera 2.

[0058] The method for detecting the inner surface of a cylinder, wherein the cylinder 5 to be detected is placed in front of the object support 11, further comprises the following steps:

[0059] Input the height H and radius R of the inner surface of the cylinder 5 to be inspected into the inspection system;

[0060] According to the data of the height H and radius R of the inner surface of the cylinder 5 to be detected, the detection system unfolds the inner surface of the cylinder 5 to be detected to produce a first rectangle, the length of the first rectangle is 2πR, and the height is H; taking one of the vertices P0 of the first rectangle as the reference point, the coordinates of any point P on the first rectangle are Among them, 0°≤n≤360°, 0≤b≤1.

[0061] In the method for detecting the inner surface of a cylinder, the detection system analyzes the image captured by the camera 2 and comprises the following steps:

[0062] The detection system analyzes the parameters of the obtained picture based on the picture taken by camera 2;

[0063] The detection system generates a second rectangle based on the data of the field of view radius F of camera 2 and the thickness r of the picture taken by the camera;

[0064] Take the point corresponding to P0 on the second rectangle and the first rectangle as the origin P0', take the length of the arc between any point P' and point P0' on the image as the horizontal coordinate value, and the horizontal coordinates of the points on the radius line segment of the ring / circular surface where point P' is located are all the arc lengths between P' and point P0'; set the distance between the point on the radius line segment and the point (center of the circle) on the inner circle of the ring as the vertical coordinate value, and the coordinates of any point P' on the second rectangle are

[0065] The detection system detects information of any point within the second rectangle.

[0066] In the method for detecting the inner surface of a cylinder, the detection system analyzes the image captured by the camera and further comprises the following steps:

[0067] The detection system matches the points in the second rectangle with the points on the first rectangle one by one, obtains the surface information of the first rectangle, and further obtains the information of the inner surface of the cylinder.

[0068] See also Figure 5 , Figure 5 It is a schematic diagram of the correspondence between the first rectangle unfolded by the inner surface of the cylinder and the second rectangle unfolded by the ring photographed by the camera; as shown in the figure, the correspondence between the first rectangle unfolded by the inner surface of the cylinder 5 to be detected and the second rectangle produced by the ring photographed by the camera 2 is as follows:

[0069] Any point on the first rectangle produced on the inner surface of the cylinder 5 to be tested satisfies the following equation:

[0070]

[0071] P y =bH, 0≤b≤1;

[0072] P x The value of P changes with n. y The value of varies with b.

[0073] The ring photographed by camera 2 produces a second rectangle where any point satisfies the following equation:

[0074]

[0075] P′ y =bF-(Fr)=bF-(F-2Hcosα), 0≤b≤1;

[0076] P′ x The value of P′ changes with n. y The value of varies with b.

[0077] P x and P′ x The variables are all n; P y and P′ y The variables are all b; when the values ​​of H and F are known;

[0078] is a constant;

[0079] is a constant, F-2Hcosα is a constant;

[0080] Therefore, there is a distance P between the point on the second rectangle and the point on the first rectangle formed by the imaging of the inner surface of the cylinder 5 to be detected by the conical reflector 4. x =AP′ x +B;P y =CP′ y +D, where A is not equal to 0 and C is not equal to 0; by analyzing the surface information of the second rectangle, the corresponding information on the first rectangle can be accurately calculated, and then the inner surface condition of the cylinder 5 to be detected can be obtained.

[0081] The corresponding relationship between the first rectangle developed from the inner surface of the cylinder 5 to be detected and the second rectangle produced from the circular surface photographed by the camera 2 is as follows:

[0082] Any point on the first rectangle produced on the inner surface of the cylinder 5 to be tested satisfies the following equation:

[0083]

[0084] P y =bH, 0≤b≤1;

[0085] P x The value of P changes with n. y The value of varies with b.

[0086] Any point on the second rectangle produced by the circular surface photographed by camera 2 satisfies the following equation:

[0087]

[0088] P′ y =br=b2Hcosα, 0≤b≤1,

[0089] P′ x The value of P′ changes with n. y The value of varies with b.

[0090] P x and P′ xThe variables are all n; P y and P′ y The variables are all b; when the values ​​of H and F are known;

[0091] is a constant;

[0092] is a constant;

[0093] Therefore, there is a distance P between the point on the second rectangle and the point on the first rectangle formed by the imaging of the inner surface of the cylinder 5 to be detected by the conical reflector. x =AP′ x ;P y =CP′ y A is not equal to 0, and C is not equal to 0. By analyzing the surface information of the second rectangle, the corresponding information on the first rectangle can be accurately calculated, and then the inner surface of the cylinder can be obtained.

[0094] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting the inner surface of a cylinder by a cylindrical inner surface detection device, characterized in that: The following steps are involved: Place the cylinder to be tested on the support; Adjust the conical reflector so that the optical center line of the camera, the cylinder to be detected and the center axis of the conical reflector are completely coincident; Adjust the height of the support so that the entire inner surface of the cylinder to be detected is imaged in the conical reflector, and the image of the inner surface of the cylinder to be detected in the conical reflector is a ring or a circular surface; Adjust the camera's field of view so that it just covers the image of the inner surface of the cylinder to be inspected formed in the conical reflector; The camera takes a picture of the image of the inner surface of the cylinder to be inspected formed in the conical reflector; The camera transmits the captured images to the detection system; The detection system analyzes the images captured by the camera; Placing the cylinder to be tested in front of the support, and further comprising the following steps: Input the height H and radius R of the inner surface of the cylinder to be inspected into the inspection system; According to the data of the height H and radius R of the inner surface of the cylinder, the detection system unfolds the inner surface of the cylinder to be detected to produce the first rectangle. The length of the first rectangle is 2πR and the height is H. Taking one of the vertices P0 of the first rectangle as the origin, the coordinates of any point P on the first rectangle are Among them, 0°≤n≤360°, 0≤b≤1; The detection system analyzes the image captured by the camera and includes the following steps: The detection system analyzes the parameters of the obtained picture based on the picture taken by the camera; The detection system generates a second rectangle based on the data of the camera's field of view radius F and the thickness r of the image taken by the camera; Take the point corresponding to P0 on the second rectangle and the first rectangle as the origin P0', take the length of the arc between any point P' and point P0' on the image as the horizontal coordinate value, and the horizontal coordinates of the points on the radius line segment of the ring / circular surface where point P' is located are all the arc lengths between P' and point P0'; set the distance between the point on the radius line segment and the point (center of the circle) on the inner circle of the ring as the vertical coordinate value, and the coordinates of any point P' on the second rectangle are The detection system detects information of any point in the second rectangle; The detection system matches the points in the second rectangle with the points on the first rectangle one by one, obtains the surface information of the first rectangle, and then obtains the information of the inner surface of the cylinder; The field of view radius of the camera is set to F, and the angle between any mirror surface of the conical reflector and the central axis of the cone of the conical reflector is α; if the inner surface height of the cylinder to be detected is H, the inner surface radius of the cylinder to be detected is R, and the thickness of the circular ring formed by the inner surface of the cylinder to be detected in the conical reflector and photographed by the camera is r, then r = 2Hcosα≤F≤R, where 45°<α<90°; The cylindrical inner surface detection device comprises: A bracket, on which a support seat is provided, wherein the support seat is height-adjustable; A camera, which is arranged on the bracket and located above the support seat; An imaging assembly, comprising a reflector seat and a conical reflector, wherein the conical reflector is arranged on the reflector seat and is located below the object holder, and the conical reflector is a concave conical reflector; A detection system connected to the camera; Among them, the optical center line of the camera, the central axis of the object holder and the central axis of the cone of the conical reflector completely coincide with each other, and the inner surface of the cylinder to be detected is imaged in the conical reflector. The camera takes the image of the cylinder to be detected in the conical reflector and transmits it to the detection system. The detection system collects data of the image of the inner surface of the cylinder to be detected and compares and analyzes it with the data of the inner surface of the cylinder to be detected.

2. The method for detecting the inner surface of a cylinder by the cylindrical inner surface detection device according to claim 1, characterized in that: When r=F, the image of the inner surface of the cylinder to be detected formed by the conical reflector is a circular surface, and the radius of the circular surface is r, r=2Hcosα.

3. The method for detecting the inner surface of a cylinder by the cylindrical inner surface detection device according to claim 1, characterized in that: When r<F, the image of the inner surface of the cylinder to be detected formed by the conical reflector is a ring, the outer radius of the ring is F, the thickness of the ring is r, r=2Hcosα, and the inner radius of the ring is Fr.

4. The method for detecting the inner surface of a cylinder according to any one of claims 1 to 3, characterized in that: The diameter of the circular surface where the top of the conical reflector is located is smaller than the inner radius of the cylinder to be detected.

Images