A 360-degree panoramic deep-rotation visual imaging device and shooting method in a pipeline

Abstract

The application provides a 360-degree panoramic deep-rotation visual imaging device and a shooting method in a pipeline, which comprises a support, a ranging-zoom camera module with ranging-zoom function and a control module, the ranging-zoom camera module comprises a camera and a depth sensor, a slip ring is installed on the top of the support, the ranging-zoom camera module is installed above the slip ring, a motor and an encoder are respectively arranged on the two sides of the slip ring, the slip ring drives the ranging-zoom camera module to rotate under the action of the motor, the encoder converts the rotating displacement data into digital pulse information during the rotation of the slip ring and transmits the digital pulse information to the control module, and the control module is arranged in the support. The application can synchronously obtain a panoramic image sequence of the inner surface of the pipeline, and obtain a high-definition panoramic image of the inner surface through an image splicing fusion method, thereby improving the efficiency of panoramic imaging in the pipeline.

Description

Technical Field

[0001] This invention relates to the field of pipeline imaging, specifically to a 360-degree panoramic deep rotational visual imaging device and imaging method for pipelines. Background Technology

[0002] Machine vision-based pipeline imaging and inspection is becoming increasingly widespread; however, dynamic imaging of pipes with small or irregular diameters remains challenging. Conventional pipeline imaging techniques suffer from poor adaptability and imaging difficulties when dealing with pipes of different sizes and irregular shapes. For example, existing catadioptric panoramic imaging devices combine a camera with lenses and mirrors such as conical mirrors and hyperboloid mirrors that meet single-viewpoint constraints, using the mirrors to project a 360° panoramic image onto a two-dimensional plane through optical principles. However, in free-form scenes, the pipe diameter varies complexly, resulting in severe distortion of the obtained panoramic unfolded image, making it difficult to apply correction algorithms and obtain an accurate panoramic image.

[0003] To achieve panoramic imaging of large-span, highly adaptable, and diverse pipes, a radial 360° panoramic depth imaging device should be developed to obtain a 360° field of view in either the vertical or horizontal direction. Furthermore, existing 360° panoramic imaging methods mostly produce regular and symmetrical circular images of the pipe's inner wall, but the pipe's cross-sectional shape is irregular, the dimensions at different locations within the pipe are uneven, and the depth of field varies at different locations along the same axis. Existing imaging devices are insufficient to meet the complex imaging requirements inside pipes. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a 360-degree panoramic deep rotational visual imaging device and imaging method for pipelines. In view of the difficulty of high-resolution imaging of the inner surface of pipelines, the present invention can simultaneously acquire panoramic image sequences of the inner surface of pipelines, and obtain high-definition panoramic images of the inner surface through image stitching and fusion methods. This solves the problems of insufficient imaging clarity, poor adaptability and mismatch of depth of field in existing devices for detecting defects on the inner surface of pipelines, and improves the efficiency of panoramic imaging in irregularly shaped pipelines.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a 360-degree panoramic depth-rotating visual imaging device for use within a pipeline. The device includes a support frame, a ranging-zoom camera module with ranging-zoom functionality, and a control module. The ranging-zoom camera module includes a camera and a depth sensor. A slip ring is mounted on the top of the support frame, and the ranging-zoom camera module is mounted above the slip ring. A motor and an encoder are respectively located on either side of the slip ring. The slip ring rotates under the action of the motor, and the encoder converts the rotational displacement data into digital pulse information during the rotation of the slip ring, which is then transmitted to the control module. The control module is located inside the support frame and is connected to the ranging-zoom camera module, the motor, and the encoder.

[0006] The motor is equipped with a first gear, and the slip ring is equipped with a retaining tooth on its side. The retaining tooth on the first gear is adapted to the retaining tooth on the side of the slip ring. The motor drives the first gear to rotate, and the first gear drives the slip ring to rotate.

[0007] The slip ring is configured as a cam structure, and a micro switch is provided on one side of the slip ring. When the slip ring rotates under the action of the motor, the cam structure triggers the micro switch to sense the rotation position of the slip ring.

[0008] The encoder has a second gear installed at its output end, which meshes with the first gear on the motor and the locking teeth on the slip ring to drive the encoder to provide real-time feedback of rotational displacement and transmit the feedback rotational displacement to the control module.

[0009] The depth sensor is a depth sensor with a field of view of less than 90 degrees.

[0010] The control module is an embedded controller.

[0011] Embodiments of the present invention also provide a method for capturing 360-degree panoramic depth-of-field rotating visual imaging inside a pipe, comprising the following steps:

[0012] S1. When the device is working, the motor is started. The first gear fixed on the output shaft of the motor drives the slip ring cam structure and the second gear to rotate through the transmission, so that the depth sensor in the ranging-zoom camera module can rotate 360° along the rotation axis of the slip ring, measure the distance of the circumferential pipe, obtain circumferential panoramic depth data, and obtain the depth distribution curve of the scene inside the pipe.

[0013] S2. Based on the depth distribution curve of the scene inside the pipe obtained in step S1, perform circumferential panoramic view segmentation of the circumferential scene depth distribution curve, and combine it with the view of the imaging sensor. α and initial position angle βThe circumferential panoramic view segmentation of the circumferential scene depth distribution curve is performed, and the calculated results are fed back to the control module for imaging control.

[0014] S3. Based on the initial angle determined in step S2 and the number of focusing imaging times at the corresponding angle position, rotate the ranging-zoom camera module one more turn to complete the shooting inside the pipe for one turn, and obtain a panoramic image sequence inside the pipe.

[0015] S4. The obtained image materials are stitched and fused using a digital image stitching and fusion algorithm to obtain a high-definition 360° panoramic image.

[0016] In step S2, the circumferential panoramic view segmentation principle includes the following steps:

[0017] S2.1 First, analyze and calculate the measured scene depth data and the maximum back depth of field d within the relevant segmented viewpoint range. bmax and the minimum depth of the foreground d fmin ;

[0018] S2.2, A cross-mode adaptive hybrid focusing panoramic depth imaging method automatically analyzes single-view depth data, evaluates the imaging mode under the corresponding viewpoint, and obtains the corresponding number of focusing imaging attempts M. i ;

[0019] S2.3, The total number of focusing imaging times N during circumferential imaging under the statistical imaging viewpoint segmentation method, where N = ∑M i .

[0020] The beneficial effects of the above technical solution of the present invention are as follows:

[0021] (1) The present invention can simultaneously acquire panoramic image sequences of the inner surface of the pipe and obtain high-definition panoramic images of the inner surface through image stitching and fusion method, thereby solving the problems of insufficient imaging clarity, poor adaptability and mismatch of depth of field of existing devices and improving the efficiency of panoramic imaging inside irregular pipes.

[0022] (2) The present invention has the characteristics of small size, high integration and fast imaging, and overcomes the defects of existing pipe inner surface imaging devices such as complex structure, large size and high cost.

[0023] (3) The present invention has a micro servo rotation mechanism and circuit system, which can realize continuous multi-dimensional rotation, realize circumferential 360° multi-viewpoint full-focus imaging and obtain panoramic sequence images of the inner surface of the pipe with full-focus performance. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the 360-degree panoramic deep rotational visual imaging device inside the pipeline in this invention. Figure 1 ;

[0025] Figure 2 This is a schematic diagram of the 360-degree panoramic deep rotational visual imaging device inside the pipeline in this invention. Figure 2 ;

[0026] Figure 3 This is a schematic diagram of the depth (nearest depth and maximum depth) curve distribution and shooting angle diagram of the target depth of field of the 360-degree panoramic depth-of-field rotating visual imaging device inside the pipeline in this invention.

[0027] Figure 4 This is a schematic diagram of scene depth distribution curve segmentation in the shooting method of the 360-degree panoramic deep rotational visual imaging device inside the pipeline in this invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Rangefinding-zoom camera module; 2. Control module; 3. Bracket; 4. Slip ring; 5. Motor; 6. First gear; 7. Encoder; 8. Second gear; 9. Micro switch. Detailed Implementation

[0030] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0031] like Figure 1 , Figure 2 As shown, an embodiment of the present invention provides a 360-degree panoramic depth-rotating visual imaging device and shooting method for use inside a pipeline. Its hardware includes a bracket 3, a ranging-zoom camera module 1 with ranging-zoom function, and a control module 2. The ranging-zoom camera module 1 includes a camera and a depth sensor. A slip ring 4 is mounted on the top of the bracket 3, and the ranging-zoom camera module 1 is mounted above the slip ring 4. A motor 5 and an encoder 7 are respectively located on both sides of the slip ring 4. The slip ring 4 drives the ranging-zoom camera module 1 to rotate under the action of the motor 5. During the rotation of the slip ring 4, the encoder 7 converts the rotational displacement data into digital pulse information and transmits it to the control module 2. The control module 2 is located inside the bracket 3 and is connected to the ranging-zoom camera module 1, the motor 5, and the encoder 7.

[0032] The motor 5 is equipped with a first gear 6, and the slip ring 4 has retaining teeth on its side. The retaining teeth on the first gear 6 are adapted to the retaining teeth on the side of the slip ring. The motor 5 drives the first gear 6 to rotate, which in turn drives the slip ring 4 to rotate. A second gear 8 is installed on the output end of the encoder 7, which meshes with the first gear 6 on the motor 5 and the retaining teeth on the slip ring 4 for transmission. The second gear 8 is used by the encoder 7 to provide real-time feedback of rotational displacement and transmits the feedback rotational displacement to the control module 2. The slip ring 4 is configured as a cam structure, and a micro switch 9 is installed on one side of the slip ring 4. When the slip ring 4 rotates under the action of the motor 5, the cam structure triggers the micro switch 9 to sense the rotational position of the slip ring 4.

[0033] The entire device is centered around the slip ring 4. The motor 5 and encoder 7 are mounted on the side of the slip ring 4. The cam structure on the slip ring 4 meshes with the first gear 6 and the second gear 8 for transmission. The rotation of the slip ring 4 is the optical axis of the camera. The overall device is small in size and highly integrated.

[0034] When the device is working, the motor 5 rotates, which in turn drives the slip ring 4 to rotate via the first gear 6. This causes the ranging-zoom camera module 1 to rotate synchronously along the optical axis (the rotation axis of the slip ring). Based on the axial or radial dimensional changes inside the pipe, it performs real-time ranging and zooming to capture continuous images, obtaining a panoramic sequence of images of the pipe's inner surface for stitching and fusion. At the same time, the encoder 7 converts the rotational displacement into digital pulse signals to control the angular displacement.

[0035] In this embodiment, the depth sensor is a VL53L5CX depth sensor, which is used to measure distances to multiple regions and multiple objects, and quickly obtain distance information within the detection field of view.

[0036] The control module is an embedded controller, using a Raspberry Pi Zero W, with built-in sensor control software, rotation control software, imaging control software, and fusion control software, which are used to control the sensor, the ranging-zoom camera module, and to fuse the captured image sequences, respectively.

[0037] This invention also provides a method for capturing 360-degree panoramic depth-of-field rotating visual imaging inside a pipe, the steps of which are as follows:

[0038] When the device is working, the motor is started, and the first gear fixed on the motor output shaft drives the slip ring cam structure and the second gear to rotate through transmission. This enables the VL53L5CX depth sensor in the ranging-zoom camera module to rotate 360° along the optical axis (slip ring rotation axis). During the rotation, the VL53L5CX depth sensor measures the distance to the circumferential pipe, obtains the circumferential panoramic depth, and transmits it to the control module. The data points are then fitted using a fitting method to obtain the scene depth distribution curve inside the pipe (foreground depth distribution curve d). f With the back depth distribution curve d b );

[0039] by Figure 3 Taking the shown perspective as an example, combined with the sensor perspective α and initial angle β A circumferential panoramic view segmentation of the circumferential scene depth distribution curve is performed. The segmentation principle is as follows: first, the measured scene depth data and the maximum back depth of field d within the relevant segmented view range are analyzed and calculated. bmax and the minimum depth of the foreground d fmin Then, based on a cross-mode adaptive hybrid focusing panoramic depth imaging method, it automatically analyzes single-view depth data, evaluates the imaging mode under the corresponding viewpoint, and obtains the corresponding number of focusing imaging times M. i Finally, the total number of focusing imaging operations N (N=∑M) during circumferential imaging under the statistical imaging viewpoint segmentation method is calculated. i ).

[0040] Among them, such as Figure 4 As shown, when the maximum depth of field d bmax and the minimum depth of the foreground d fmin The characteristic region conforming to single-focus imaging (d) fA ,d bA When ), similar results can be achieved in the interval. <d2>One imaging session corresponds to 1 imaging session; when the feature region (d) is met... fB ,d bB At the same time, based on the cross-mode adaptive hybrid focusing panoramic depth imaging formula, similar results can be achieved in the interval... <d1> <d2> <d3>Internal three - time imaging, and the corresponding number of imaging times is 3.

[0041] According to the above method, when the camera view angle α is fixed, by modifying the initial angle β , different combinations of imaging positions can be obtained, so that there are different segmentation forms (and their corresponding imaging methods and total number of imaging times N) during annular panoramic imaging. Therefore, during the automatic decision - making imaging process of the camera system, based on the principle that the fewer the focusing times, the better, the imaging method is decided to achieve the optimal imaging quality and efficiency.

[0042] Finally, based on the software development platform of Raspberry Pi Zero W, corresponding photos are taken according to the divided n (n≥8) depth data distribution regions. First, the camera is at the initial angle β After focusing and imaging according to the depth data processed in this region, a high - definition image within this field of view is obtained. After the shooting is completed, the position information is fed back to the control module. When the position i < n, according to the division of the depth distribution region, the camera rotates 360° / n, adjusts the focal length again according to the new depth data within the rotated field of view and images again, obtaining the inner - surface image of the pipeline within the current field of view. Continuously repeat the above operations until i = n. The camera completes a full - circle shooting, obtaining a sequence of panoramic images of the pipeline interior, and the program ends. The obtained image materials are used with the digital image stitching and fusion algorithm to obtain a high - definition 360° panoramic image.

[0043] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. < / d2> < / d1>

Claims

1. A method for capturing images using a 360-degree panoramic depth-of-field rotating visual imaging device inside a pipe, characterized in that, Includes the following steps: S1. When the device is working, the motor is started. The first gear fixed on the output shaft of the motor drives the slip ring cam structure and the second gear to rotate through the transmission, so that the depth sensor in the ranging-zoom camera module can rotate 360° along the rotation axis of the slip ring, measure the distance of the circumferential pipe, obtain circumferential panoramic depth data, and obtain the depth distribution curve of the scene inside the pipe. S2. Based on the depth distribution curve of the scene inside the pipe obtained in step S1, perform circumferential panoramic view segmentation of the circumferential scene depth distribution curve. Combine the imaging sensor viewpoint α and the initial position angle β to perform circumferential panoramic view segmentation of the circumferential scene depth distribution curve, and feed the calculated results back to the control module for imaging control. The principle of circumferential panoramic view segmentation includes the following steps: S2.1 Analyze and calculate the measurement scene depth data and the maximum back depth of field dbmax and the minimum front depth of field dfmin within the relevant segmented view range; S2.2, The cross-mode adaptive hybrid focusing panoramic depth imaging method automatically analyzes single-view depth data, evaluates the imaging mode under the corresponding view, and obtains the corresponding focusing imaging times Mi; S2.3, The total number of focusing imaging times N under the statistical imaging viewpoint segmentation method for circumferential imaging, where N = ∑Mi; S3. Based on the initial angle determined in step S2 and the number of focusing imaging times at the corresponding angle position, rotate the ranging-zoom camera module one more turn to complete the shooting inside the pipe for one turn, and obtain a panoramic image sequence inside the pipe. S4. The obtained image materials are stitched and fused using a digital image stitching and fusion algorithm to obtain a high-definition 360° panoramic image.

2. A 360-degree panoramic deep-depth rotating visual imaging device for use inside a pipeline, characterized in that, The visual imaging device is applied to the shooting method of claim 1. The visual imaging device includes a bracket, a ranging-zoom camera module with ranging-zoom function, and a control module. The ranging-zoom camera module includes a camera and a depth sensor. A slip ring is installed on the top of the bracket, and the ranging-zoom camera module is installed above the slip ring. A motor and an encoder are respectively provided on both sides of the slip ring. The slip ring drives the ranging-zoom camera module to rotate under the action of the motor. The encoder converts the rotational displacement data into digital pulse information during the rotation of the slip ring and transmits it to the control module. The control module is located inside the bracket.

3. The 360-degree panoramic deep-depth rotating visual imaging device inside a pipeline according to claim 2, characterized in that, The motor is provided with a first gear, and the slip ring is provided with a retaining tooth on its side. The retaining tooth on the first gear is adapted to the retaining tooth on the side of the slip ring. The motor drives the first gear to rotate, and the first gear drives the slip ring to rotate.

4. The 360-degree panoramic deep-depth rotating visual imaging device inside a pipeline according to claim 2, characterized in that, The slip ring is configured as a cam structure, and a micro switch is provided on one side of the slip ring. When the slip ring rotates under the action of the motor, the cam structure triggers the micro switch to sense the rotation position of the slip ring.

5. The 360-degree panoramic deep-depth rotating visual imaging device inside a pipeline according to claim 2, characterized in that, The encoder has a second gear installed at its output end, which meshes with the first gear on the motor and the retaining teeth on the slip ring for transmission.

6. The 360-degree panoramic deep-depth rotating visual imaging device inside a pipeline according to claim 2, characterized in that, The depth sensor is a depth sensor with a field of view of less than 90 degrees.

7. The 360-degree panoramic deep-depth rotating visual imaging device inside a pipeline according to claim 2, characterized in that, The control module is an embedded controller.

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