Light underwater panoramic calibration device and working process

Abstract

A guide rail is fixed below a support, a linear driving motor is fixedly installed at one end of the support, a synchronous belt mechanism is installed at the output end of the support, a connecting piece is fixed to a synchronous belt of the synchronous belt mechanism, a reference object is fixed to the bottom of the connecting piece, and meanwhile the connecting piece is matched with the guide rail. Under the positive and negative rotation of the linear driving motor, the connecting piece drives the reference object to slide along the guide rail; a rotary driving motor is fixed at the other end, a camera bracket is mounted at the output end of the rotary driving motor, and a multi-view camera is fixed at the bottom of the camera bracket and corresponds to a reference object; the system further comprises a water surface processing platform at the shore end of the pool, upper computer software is arranged on the water surface processing platform, the water surface processing platform is connected with the linear driving motor, the rotary driving motor and the multi-view camera through a watertight cable set, laying of scenes at different distances can be rapidly completed underwater, and rapid optical calibration of the multi-view camera is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater calibration devices, and in particular to a lightweight underwater panoramic calibration device and its working process. Background Art

[0002] Underwater multi-camera uses multi-channel image fusion stitching technology, which can achieve the function of large-range imaging of underwater scenes. Compared with traditional underwater optical imaging equipment, the camera using multi-channel image fusion stitching technology has no field of view blind area and has low requirements for the mobility of the underwater platform. When searching for underwater targets, it is more efficient, not easy to miss targets, and can quickly distinguish the distribution direction of targets.

[0003] To ensure that underwater targets can be effectively and completely presented in the fused image, it is necessary to ensure the quality of the fused image of different channels, and the improvement of the fused quality mainly comes from the optical calibration parameters of different channels. When the current land environment calibration parameters are applied underwater, due to the change of the optical medium, there will be missing and overlapping of image information, resulting in the loss of underwater target details or repeated statistics. Therefore, the calibration of different channels can only be carried out underwater.

[0004] The difference between underwater and land is that the underwater scene features are weak and few. According to the land calibration method, it is easy to cause failure of feature capture. When placing reference objects in different directions, it occupies a large space, and when changing the distance of the reference object, it is necessary to salvage the reference object out of the water for scene rearrangement. It consumes a lot of manpower and physical resources, and this calibration method is not feasible for some small underwater spaces. Therefore, if a device dedicated to underwater calibration of different channels of images is formed, with a reduced volume and reduced deployment difficulty, it can be quickly deployed, and can quickly complete optical calibration in a narrow underwater space, which will reduce the requirements for underwater operation guarantee conditions and can improve the calibration efficiency of underwater imaging equipment. Summary of the Invention

[0005] The applicant of the present invention aims at the above-mentioned disadvantages in the existing production technology, and provides a lightweight underwater panoramic calibration device and its working process, so as to be able to meet the optical calibration work of underwater multi-cameras at different distances in a narrow underwater area, with the advantages of small volume and light weight, and can quickly complete the deployment of different distance scenes underwater, realizing the rapid optical calibration of multi-cameras.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A lightweight underwater panoramic calibration device, comprising a horizontally arranged bracket, a guide rail is fixed below the bracket, a linear drive motor is fixedly installed at one end of the bracket, a synchronous belt mechanism is installed at the output end of the linear drive motor, a connecting piece is fixed on the synchronous belt of the synchronous belt mechanism, a reference object is fixed at the bottom of the connecting piece, and at the same time the connecting piece is matched with the guide rail. Under the forward and reverse rotation of the linear drive motor, the reference object is driven to slide along the guide rail through the connecting piece;

[0008] A rotary drive motor is fixed at the other end of the bracket, a camera bracket is installed at the output end of the rotary drive motor, a multi-camera is fixed at the bottom of the camera bracket, and the multi-camera corresponds to the reference object;

[0009] It also includes a water surface treatment platform at the pool shore end, an upper computer software is set on the water surface treatment platform, and the water surface treatment platform is connected to the linear drive motor, the rotary drive motor and the multi-camera through a waterproof cable group.

[0010] Its further technical solution lies in:

[0011] A displacement sensor is installed on the guide rail.

[0012] A rotary encoder is installed inside the rotary drive motor.

[0013] The water surface treatment platform controls the linear drive motor and the rotary drive motor to move to the specified position, and at the same time also receives the position feedback of the rotary encoder built in the linear drive motor and the displacement sensor of the guide rail; it controls the multi-camera to collect images through different image channels connected to the multi-camera, and at the same time completes the collection of image data for the upper computer software to display and process.

[0014] The camera bracket adopts a rod structure with adjustable length.

[0015] The installation position of the reference object is perpendicular to the guide rail.

[0016] The multi-camera can have more than two windows.

[0017] The multi-camera can have eight windows arranged in a ring.

[0018] The axes of each window are coplanar and parallel to the bracket.

[0019] The working process of a lightweight underwater panoramic calibration device includes the following operation steps:

[0020] The first step: Preparation work;

[0021] Install the calibration device and place it below the water surface;

[0022] The second step: Start work;

[0023] Through the water surface treatment platform opening device, drive the linear drive motor to drive the reference object to move on the guide rail until the reference object reaches the specified distance position from the multi-camera.

[0024] Step 3: Confirm the camera startup and initial position;

[0025] Start the rotary drive motor to drive the multi-camera to rotate to the initial position. Assume that the multi-camera has eight windows numbered a - h; the initial position is at the midline of two adjacent windows a and b among the multiple windows surrounding the multi-camera.

[0026] Step 4: Acquisition work;

[0027] After determining the starting position, run the host computer software to connect the multi-camera, and complete the image acquisition of channels a and b in the form of software instruction triggering. At this time, the reference object is located on the right and left sides of the images of channels a and b respectively, and the initial position images are encoded as a2 and b1.

[0028] Step 5: After completing the above steps 1 - 4, continue to start the rotary drive motor to align the midline of window b and window c with the reference object, run the host computer software to repeat the above operation to form images encoded as b2 and c1, and repeat the above operation to complete the acquisition of c2, d1, d2, e1, e2, f1, f2, g1, g2, h1, h2, a1 in sequence.

[0029] Step 6: Re - cut and combine the 16 images a1 - h2 collected through the host computer software. Each image is cut into two equal - width left and right parts. Taking a1 as an example, it is cut into a1L and a1R, and a total of 32 images a1L, a1R - h2L, h2R are formed.

[0030] Step 7: After completing the image recombination, the recombination process is that a1L and a2R are combined to form image A, b1L and b2R are combined to form image B; and so on to obtain images of eight channels A - H. Each image has a picture of the reference object on both the left and right parts. Taking this as the input, complete the matching and recognition of image feature points for each channel through the host computer software, and complete the underwater optical calibration of multiple windows of the multi - camera.

[0031] Step 8: After the specified - distance calibration is completed, drive the linear drive motor to drive the reference object to move to a new position along the guide rail, and repeat all the above steps to complete the new calibration work.

[0032] The beneficial effects of the present invention are as follows:

[0033] The structure of the present invention is compact and reasonable, and it is convenient to operate. The underwater multi-view camera of the present invention uses image fusion technology to achieve underwater observation in a large field of view range, and can efficiently search for underwater targets. Before using the underwater multi-view camera, it is necessary to calibrate the camera lens underwater. According to the current calibration method on land, it is necessary to distribute scene reference objects with rich features at different distances around the camera. Applying this method to underwater requires high requirements for the size and depth of the pool, and the calibration device will become large, and it needs to be frequently hoisted in and out of the water, which is not conducive to actual operation. When calibrating multiple devices, there will be problems of large calibration difficulty and low efficiency. The underwater panoramic calibration device in the present invention can achieve rapid calibration of different distances of the device in a narrow pool area, reduce the size of the calibration device, facilitate placement in water, and improve the calibration efficiency of the underwater multi-view camera.

[0034] Meanwhile, the present invention also has the following advantages:

[0035] (1) The structure of the present invention is simple, occupies a small space, and has a high integration degree, which is suitable for operating in a narrow pool.

[0036] (2) The present invention can adapt to the rapid calibration and calibration of multi-channel optics of multi-view cameras at different underwater distances.

[0037] (3) It can be quickly arranged in the pool, and is controlled through the water surface unit and special software, with a high degree of automation, and there is no need to frequently emerge from the water and arrange the underwater scene. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic structural diagram of the light underwater panoramic calibration device of the present invention.

[0039] Figure 2 is a schematic diagram of the starting position during the working process of the present invention.

[0040] Figure 3 is a schematic diagram (a2) of the starting position and the channel acquisition image during the working process of the present invention.

[0041] Figure 4 is a schematic diagram (b1) of the starting position and the channel acquisition image during the working process of the present invention.

[0042] Figure 5 is Figure 3 the actual effect diagram.

[0043] Figure 6 is Figure 4 the actual effect diagram.

[0044] Figure 7 is an example diagram of the synthesized image A of a1L and a2R of the present invention.

[0045] Figure 8 This is an example diagram of multi-channel image synthesis of the present invention.

[0046] Figure 9 This is an example diagram of the calibration result of the synthesized image of the present invention.

[0047] Figure 10 This is the actual underwater scene effect diagram of the present invention.

[0048] Wherein: 1. Bracket; 2. Guide rail; 3. Linear drive motor; 4. Rotary drive motor; 5. Reference object; 6. Water surface treatment platform; 7. Watertight cable group; 8. Camera bracket; 9. Multi-camera; 10. Host computer software. Specific implementation mode

[0049] The following combines with the attached drawings to illustrate the specific implementation mode of the present invention.

[0050] As Figures 1-10 shown, the lightweight underwater panoramic calibration device of this embodiment includes a horizontally arranged bracket 1. A guide rail 2 is fixed below the bracket 1. A linear drive motor 3 is fixedly installed at one end of the bracket 1. A synchronous belt mechanism is installed at the output end of the linear drive motor 3. A connecting member is fixed on the synchronous belt of the synchronous belt mechanism. A reference object 5 is fixed at the bottom of the connecting member. At the same time, the connecting member is matched with the guide rail 2. Under the forward and reverse rotation of the linear drive motor 3, the reference object 5 is driven by the connecting member to slide along the guide rail 2;

[0051] A rotary drive motor 4 is fixed at the other end of the bracket 1. A camera bracket 8 is installed at the output end of the rotary drive motor 4. A multi-camera 9 is fixed at the bottom of the camera bracket 8. The multi-camera 9 corresponds to the reference object 5;

[0052] It also includes a water surface treatment platform 6 on the pool shore end. A host computer software 10 is set on the water surface treatment platform 6. The host computer software 10 provides the operating software and hardware environment. The water surface treatment platform 6 is connected to the linear drive motor 3, the rotary drive motor 4 and the multi-camera 9 through a watertight cable group 7.

[0053] A displacement sensor is installed on the guide rail 2.

[0054] A rotary encoder is installed inside the rotary drive motor 4.

[0055] The water surface treatment platform 6 controls the linear drive motor 3 and the rotary drive motor 4 to move to the specified position. At the same time, it also receives the position feedback of the rotary encoder built in the linear drive motor 3 and the displacement sensor of the guide rail 2; It controls the multi-camera 9 to collect images in different image channels through connection with the multi-camera 9, and at the same time completes the collection of image data for the host computer software 10 to display and process.

[0056] The camera bracket 8 adopts a rod structure with adjustable length.

[0057] The installation position of the reference object 5 is perpendicular to the guide rail 2.

[0058] The multi-view camera 9 can have more than two windows.

[0059] The multi-view camera 9 can have eight windows arranged in a ring.

[0060] The axes of each window are coplanar and parallel to the support 1.

[0061] The following is an introduction to the specific structures and functions of the components of a lightweight underwater panoramic calibration device according to the present invention:

[0062] Support 1 - provides an installation reference for the guide rail 2, linear drive motor 3, rotary drive motor 4, and reference object 5, and also has a placement point for the support 1 for hoisting work in the pool.

[0063] Guide rail 2 - fixed below the support 1, provides a linear motion constraint for the reference object 5. The guide rail 2 has a displacement sensor, which can provide the actual distance between the current reference object 5 and the multi-view camera 9 to the water surface processing end.

[0064] Linear drive motor 3 - fixed at the end of the support 1, connected to the reference object 5 through a synchronous belt. When the linear drive motor 3 rotates forward and backward, it can drive the reference object 5 to move in different directions to reach the specified distance position from the multi-view camera 9.

[0065] Rotary drive motor 4 - fixed at one end of the support 1, the motor rotation axis is perpendicular to the guide rail 2, drives the camera support 8 and the multi-view camera 9 to rotate, and is equipped with a rotary encoder inside. The rotation angle is controlled by the water surface processing platform 6.

[0066] Reference object 5 - placed below the guide rail 2, vertically placed, can move horizontally on the guide rail 2 under the drive of the linear drive motor 3. The reference object 5 is distributed with characteristic point patterns, within the field of view angle of the multi-view camera 9, and is used to provide obvious characteristic images for the underwater images collected.

[0067] Water surface processing platform 6 - placed at the pool shore end, provides a running software and hardware environment for the upper computer software 10, and is connected to the linear drive motor 3, rotary drive motor 4, and multi-view camera 9 through a waterproof cable set 7. It can control the linear drive motor 3 and the rotary drive motor 4 to move to the specified position, and at the same time receive the position feedback of the built-in rotary encoder of the linear drive motor 3 and the displacement sensor of the guide rail 2. By connecting to the multi-view camera 9, it controls different image channels of the multi-view camera 9 to collect images, and at the same time completes the collection of image data for the upper computer software 10 to display and process.

[0068] The watertight cable group 7 provides an underwater data interaction and power supply channel for the water surface treatment platform 6, the linear drive motor 3, the rotary drive motor 4, and the multi-camera 9.

[0069] The camera support 8 is used to provide an installation reference for the multi-camera 9, adjust the height, and is fixedly connected to the multi-camera 9 and the rotary drive motor 4, so that the multi-camera 9 is at the midline height position of the reference object 5.

[0070] The multi-camera 9 is a device to be calibrated, fixedly installed at the lower end of the camera support 8. Its axis of rotation coincides with the axis of rotation of the rotary drive motor 4. It is connected to the water surface treatment platform 6 through the watertight cable group 7, is controlled by the host computer software 10, and pushes image data to it. The multi-camera 9 has a plurality of windows arranged in a ring. The axes of each window are coplanar and parallel to the support 1.

[0071] The host computer software 10 runs on the water surface treatment platform 6 and is used to control the guide rail 2, the linear drive motor 3, the rotary drive motor 4, and the multi-camera 9 and read and process the returned data, including reading the position data of the displacement sensor of the guide rail 2 and the rotary encoder of the rotary drive motor 4, and the image data of different channels of the multi-camera 9. It has the functions of encoding, sorting, cropping, and combining images of different channels. And it can perform feature matching recognition on the cropped and combined images to form optical calibration data.

[0072] During the actual working process:

[0073] When all the optical calibration devices are placed below the water surface, the device is started through the water surface treatment platform 6, and the linear drive motor 3 is driven to drive the reference object 5 to move on the guide rail 2 to a specified distance position from the multi-camera 9. The rotary drive motor 4 is started to drive the multi-camera 9 to rotate to the initial position. In fact, the multi-camera 9 can have more than two windows. In this embodiment, the multi-camera 9 with 8 windows is taken as an example for illustration, numbered a to h. The initial position is at the midline of two adjacent windows a and b among the 8 windows surrounding the multi-camera 9. As Figure 2 shown, after determining the starting position, the host computer software 10 is run to connect the multi-camera 9, and the image acquisition of channels a and b is completed in the form of software instruction triggering. At this time, the reference object 5 is respectively on the right and left sides of the images of channels a and b, and the initial position images are encoded as a2 and b1.

[0074] After completing the above steps, continue to start the rotary drive motor 4, align the midline of window b and window c with the reference object 5, run the host computer software 10 to repeat the above operation, form images encoded as b2 and c1, and repeat the above operation to complete the acquisition of c2, d1, d2, e1, e2, f1, f2, g1, g2, h1, h2, a1 in sequence.

[0075] The 16 images from a1 to h2 collected are re - sliced and combined through the host computer software 10. Each image is sliced into two equal - width left and right parts. Taking a1 as an example, it is sliced into a1L and a1R, and a total of 32 images a1L, a1R~h2L, h2R are formed.

[0076] Image recombination is completed. The recombination process is that a1L and a2R are combined to form image A, and b1L and b2R are combined to form image B. And so on, images of 8 channels from A to H are obtained. As Figure 8 shown, there are pictures of the reference object 5 in the left and right parts of each image. Taking this as the input, the host computer software 10 completes the matching and recognition of feature points of each channel image, and completes the underwater optical calibration of multiple windows of the multi - camera 9. As Figure 9 shown.

[0077] After the calibration at a specified distance is completed, the linear drive motor 3 is driven to drive the reference object 5 to move to a new position along the guide rail 2, and the above steps are repeated to complete the new calibration work.

[0078] The above description is an explanation of the present invention, not a limitation of the invention. The scope defined by the present invention is referred to the claims. Within the protection scope of the present invention, any form of modification can be made.

Claims

1. A lightweight underwater panoramic calibration device, characterized in that: The invention comprises a horizontally arranged bracket (1), a guide rail (2) being fixed below the bracket (1), a linear drive motor (3) being fixedly mounted on one end of the bracket (1), a synchronous belt mechanism being mounted on the output end of the linear drive motor (3), a connecting piece being fixed on the synchronous belt of the synchronous belt mechanism, a reference object (5) being fixed at the bottom of the connecting piece, and the connecting piece being matched with the guide rail (2), and the reference object (5) being driven to slide along the guide rail (2) by the connecting piece under the forward and reverse rotation of the linear drive motor (3); A rotation drive motor (4) is fixed to the other end of the support (1); a camera support (8) is installed at the output end of the rotation drive motor (4); a multi-eye camera (9) is fixed to the bottom of the camera support (8); and the multi-eye camera (9) corresponds to the reference object (5); The invention also comprises a water surface processing platform (6) at the bank end of the pool. The water surface processing platform (6) is provided with a host computer software (10). The host computer software (10) provides a running software and hardware environment. The water surface processing platform (6) is connected to the linear drive motor (3), the rotary drive motor (4) and the multi-eye camera (9) via a watertight cable group (7).

2. A lightweight underwater panoramic calibration device as claimed in claim 1, characterized in that: A displacement sensor is installed on the guide rail (2).

3. A lightweight underwater panoramic calibration device as claimed in claim 2, characterized in that: A rotary encoder is installed inside the rotary drive motor (4).

4. A lightweight underwater panoramic calibration device as claimed in claim 3, characterized in that: The water surface treatment platform (6) controls the linear drive motor (3) and the rotary drive motor (4) to move to a specified position, and also receives position feedback from the rotary encoder built into the linear drive motor (3) and the displacement sensor of the guide rail (2); it controls different image channels of the multi-eye camera (9) to collect images by connecting to the multi-eye camera (9), and simultaneously completes image data collection for display and processing by the host computer software (10).

5. A lightweight underwater panoramic calibration device as claimed in claim 1, characterized in that: The camera bracket (8) adopts a rod structure with adjustable length.

6. A lightweight underwater panoramic calibration device as claimed in claim 1, characterized in that: The installation position of the reference object (5) is perpendicular to the guide rail (2).

7. A lightweight underwater panoramic calibration device as claimed in claim 1, characterized in that: The multi-eye camera (9) can have more than two windows.

8. A lightweight underwater panoramic calibration device as claimed in claim 8, characterized in that: The multi-eye camera (9) can have eight windows arranged in a ring.

9. A lightweight underwater panoramic calibration device as claimed in claim 8, characterized in that: The axis of each window is coplanar and parallel to the bracket (1).

10. A working process of the lightweight underwater panoramic calibration device as claimed in claim 1, characterized in that: The steps are as follows: Step 1: Preparation; Install the calibration device and place it below the water surface; Step 2: Start the work; The device is opened by the water surface processing platform (6), and the linear drive motor (3) is driven to drive the reference object (5) to move on the guide rail (2) until the reference object (5) is at a specified distance from the multi-eye camera (9); Step 3: Camera startup and initial position confirmation; The rotary drive motor (4) is started to drive the multi-eye camera (9) to rotate to an initial position. Assume that the multi-eye camera (9) has eight windows, which are numbered a to h; the initial position is the midpoint of two adjacent windows a and b of the multiple windows surrounding the multi-eye camera (9); Step 4: Collection work; After determining the starting position, the host computer software (10) is run to connect the multi-eye camera (9), and the image acquisition of the a and b channels is completed in the form of software instruction triggering. At this time, the reference object (5) is located on the right and left sides of the a and b channel images respectively, and the initial position image codes are a2 and b1; Step 5: After completing the steps from step 1 to step 4, continue to start the rotary drive motor (4), align the center line of window b and window c with the reference object (5), run the host computer software (10) and repeat the above operation to form images coded as b2 and c1, and repeat the above operation to complete the acquisition of numbers c2, d1, d2, e1, e2, f1, f2, g1, g2, h1, h2, and a1 in sequence; Step 6: The collected 16 images a1 to h2 are re-segmented and combined by the host computer software (10), and each image is segmented into two parts with equal widths on the left and right. For example, a1 is segmented into a1L and a1R, forming a total of 32 images a1L, a1R to h2L, h2R; Step 7: Complete image reorganization. The reorganization process is to combine a1L and a2R to form image A, and combine b1L and b2R to form image B. In this way, eight channels of images A to H are obtained. The left and right parts of each image have pictures of reference objects (5). With these as input, the host computer software (10) completes the matching and recognition of feature points of each channel image, and completes the underwater optical calibration of multiple windows of the multi-eye camera (9). Step 8: After the designated distance calibration is completed, the linear drive motor (3) is driven to drive the reference object (5) to move to a new position along the guide rail (2), and all the above steps are repeated to complete the new calibration work.

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