WO2022078421A1

WO2022078421A1 - Multi-pitch-angle intelligent visual 3d information collection device

Info

Publication number: WO2022078421A1
Application number: PCT/CN2021/123706
Authority: WO
Inventors: 左忠斌; 左达宇
Original assignee: 左忠斌
Priority date: 2020-10-15
Filing date: 2021-10-14
Publication date: 2022-04-21

Abstract

A visual 3D information collection device, comprising an image collection apparatus (1), a rotation apparatus (2), a support apparatus (4) and an angle setting apparatus (5), wherein the rotation apparatus (2) drives the support apparatus (4) to rotate; the angle setting apparatus (5) and the image collection apparatus (1) are arranged on the support apparatus (4); and the angle setting apparatus (5) is used for setting an included pitch angle between an optical axis (P) of the image collection apparatus (1) and a rotation plane. A method and device which can be applied to 3D information collection of an outer surface and an inner space of an object are provided. A camera collection position is optimized by means of measuring the distance between a rotation center and a target object and the distance between an image sensing element and the target object, such that the 3D construction speed and effect are both taken into consideration.

Description

A multi-pitch angle intelligent visual 3D information collection device

technical field

The invention relates to the technical field of topography measurement, in particular to the technical field of 3D topography measurement.

Background technique

When performing 3D measurement, 3D information needs to be collected first. Commonly used methods include the use of machine vision and structured light, laser ranging, and lidar.

Structured light, laser ranging, and lidar all require an active light source to be emitted to the target, which will affect the target in some cases, and the cost of the light source is high. Moreover, the structure of the light source is relatively precise and easy to be damaged.

The machine vision method is to collect pictures of objects from different angles, and match and stitch these pictures to form a 3D model, which is low-cost and easy to use. When collecting pictures from different angles, multiple cameras can be set at different angles of the object to be tested, or pictures can be collected from different angles by rotating a single or multiple cameras. At present, the collected objects include the outer surface of the object and the interior of the object, and the prior art has never mentioned how to combine the two for a unified solution. That is to say, there is currently no acquisition method or device that can be applied to the outer surface of the object and the interior space of the object.

In addition, in the prior art, it has also been proposed to use empirical formulas including rotation angle, target object size, and object distance to define the camera position, so as to take into account the synthesis speed and effect. In practice, however, this is found to be feasible in wrap-around 3D acquisition, where the target size can be measured in advance. However, in an open space, it is difficult to measure the target in advance. For example, it is necessary to collect and obtain 3D information of streets, traffic intersections, buildings, tunnels, traffic flows, etc. (not limited to this). This makes this approach ineffective. Even small fixed targets, such as furniture, human body parts, etc., can be measured in advance, but this method is still limited: the size of the target is difficult to accurately determine, especially in some applications. Frequent replacements bring a lot of extra work per measurement and require specialized equipment to accurately measure irregular targets. The measurement error leads to the camera position setting error, which will affect the acquisition and synthesis speed and effect; the accuracy and speed need to be further improved.

Therefore, there is an urgent need for a method and device for acquiring accurate, efficient and convenient 3D information of an object and applicable to the outer surface and interior of the object.

SUMMARY OF THE INVENTION

In view of the above problems, it is proposed that the present invention provides a visual 3D information acquisition device that overcomes the above problems or at least partially solves the above problems.

Embodiments of the present invention provide a visual 3D information acquisition device, including an image acquisition device, a rotation device, a support device, and an angle setting device;

The rotating device drives the supporting device to rotate;

An angle setting device and an image acquisition device are arranged on the support device;

The angle setting device is used to set the pitch angle between the optical axis of the image acquisition device and the rotation plane;

During the rotation process of the image acquisition device, the included angle α of the optical axes of two adjacent acquisition positions satisfies the following conditions:

Among them, R is the distance from the rotation center to the surface of the target object, T is the sum of the object distance and the image distance during acquisition, d is the length or width of the photosensitive element of the image acquisition device, F is the lens focal length of the image acquisition device, and u is the experience coefficient.

In alternative embodiments, u<0.498, preferably u<0.411, particularly preferably u<0.359, u<0.250, or u<0.214, or u<0.191, or u<0.068, or u<0.048.

In an optional embodiment, the set included angle may be in the range of 0° to 180°, 90° to -90°, and 0° to -180°.

In an alternative embodiment, the image acquisition device translates relative to the rotational plane.

In an optional embodiment, the set angle is 20°, 40°, 60°, 80°, 90°, 100°, 120°, 160°, 180°.

In an optional embodiment, the angle setting device is an adjustable angle setting device.

In an optional embodiment, the angle setting device is a fixed angle setting device.

In an optional embodiment, the support device includes a translation unit such that the image capture device is offset relative to the center of rotation of the device.

In an optional embodiment, the support device enables the image capture device to be located at any point in space and offset from the center of rotation of the device.

Embodiments of the present invention further provide a 3D synthesis/recognition apparatus and method, including any of the above-mentioned devices.

Embodiments of the present invention also provide an object manufacturing/display apparatus and method, including the apparatus described in any of the above claims.

Another aspect of the present invention also provides a visual 3D information acquisition device, including an image acquisition device, a rotation device, a carrying device and a pitching device;

The image capturing device is arranged on the pitching device, so that the image capturing device can pitch and rotate along the vertical plane;

The pitching device is connected with the rotating device, and the rotating device drives it to rotate;

The angle α between the optical axes of the image acquisition device at two adjacent acquisition positions satisfies the following conditions:

In alternative embodiments, u<0.498, or u<0.411, or u<0.392, or u<0.296, or u<0.202, or u<0.041, or u<0.028.

In an optional embodiment, the pitching device is manually adjusted or driven by a motor.

In an optional embodiment, the tilting device is a fixed bracket, so that the optical axis of the image capturing device can form a certain angle with the rotation plane.

In an optional embodiment, the optical acquisition ports of the image acquisition device are all facing away from the direction of the rotation axis.

In an optional embodiment, a ranging device is also included, and the ranging device rotates synchronously with the image capturing device.

In an optional embodiment, a plurality of marking points are set at the position of the target object.

In an optional embodiment, the pitching device further includes a locking mechanism.

An embodiment of the present invention further provides a 3D synthesis identification device, including any of the above-mentioned devices.

An embodiment of the present invention further provides an object manufacturing and display device, including any of the above-mentioned devices.

Inventions and technical effects

1. For the first time, a method and device that can be applied to the acquisition of 3D information on the outer surface and inner space of an object are proposed.

2. Optimize the camera acquisition position by measuring the distance between the rotation center and the target, and the distance between the image sensor element and the target, so as to take into account the speed and effect of 3D construction.

3. For the first time, it is proposed to adjust the pitch angle of the camera, so that the 3D acquisition and modeling of the target whose surface (the inner surface of the target or the surface of the target in the peripheral field of view) is not perpendicular to the horizontal plane can be performed by the rotation of the camera.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating preferred embodiments only and are not to be considered limiting of the invention. Also, the same components are denoted by the same reference numerals throughout the drawings. In the attached image:

FIG. 1 shows a schematic structural diagram of a 3D information collection device provided by an embodiment of the present invention;

2 shows a schematic diagram of setting an angle setting device of a 3D information collection device provided by an embodiment of the present invention to 20°;

FIG. 3 is a schematic diagram illustrating that the angle setting device of the 3D information collection device provided by the embodiment of the present invention is set to 90°;

FIG. 4 shows a schematic diagram of setting an angle setting device of a 3D information collection device provided by an embodiment of the present invention to -90°;

FIG. 5 shows another schematic structural diagram of a 3D information collection device provided by an embodiment of the present invention;

FIG. 6 shows a schematic structural diagram of a pitch device for a 3D information collection device provided by an embodiment of the present invention;

FIG. 7 shows another schematic structural diagram of a pitch device of a 3D information collection device provided by an embodiment of the present invention;

The corresponding relationship between the reference numerals in the accompanying drawings and the components is as follows:

1 image acquisition device;

2 rotating device;

3 carrying device;

4 supporting devices;

5 angle setting device;

6 bars;

41 pitching device

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be more thoroughly understood, and will fully convey the scope of the present disclosure to those skilled in the art.

3D information acquisition equipment structure

In order to solve the above technical problems, an embodiment of the present invention provides an intelligent visual 3D information acquisition device, please refer to FIG. 1 , including an image acquisition device 1, a rotation device 2, a support device 4, an angle setting device 5 and a carrying device. 3.

One end of the supporting device 4 is connected to the rotating device 2 , and the other end is installed with the image capturing device 1 through the angle setting device 5 , so that the supporting device 4 drives the image capturing device 1 to rotate around the rotation center under the driving of the rotating device 2 . The support device 4 can preferably be a telescopic structure, that is, the length of the support device 4 can be adjusted, so that support devices of different lengths can be selected according to the size of the target or target area to meet the collection requirements.

The XY plane is the plane on which the rotating device drives the support device and the image acquisition device to rotate, and the direction of the lens of the image acquisition device is the Y direction; the long side direction of the CCD or CMOS chip of the image acquisition device is the X direction, and when looking toward the lens, The right side is the positive X direction; the vertical XY plane upward is the positive Z direction.

The angle setting device 5 can adjust and set the direction of the optical capture port (optical axis p) of the image capture device 1 . The plane in which the rotating device 2 drives the supporting device 4 and the image acquisition device 1 to rotate is called the XY plane, and the direction of the lens of the image acquisition device is the Y direction. The angle setting device 5 can set the pitch angle of the image capturing device, that is, the image capturing device can be rotated in the YZ direction through the angle setting device. Taking the Y direction as the 0° direction, as shown in Figure 1, that is, the direction when the optical axis is parallel to the rotation plane. And it is defined that the rotation of the optical collection port in the Z direction (ie upward) is the direction of increasing the angle.

Please refer to FIGS. 2-3 , the angle setting device 5 can make the optical axis p of the optical capture port of the image capture device 1 rotate a certain angle away from the rotation plane, for example, to 20°, 40°, 60°, 80° , 90°, 100°, 120°, 160°. That is to say, there is an included angle between the optical axis of the image acquisition device along the acquisition direction of the optical acquisition port and the rotation plane, that is, the set angle.

Of course, you can also continue to increase the set angle, such as 180°, 270°, and so on. However, when the image acquisition device is rotated more than 180°, it is actually equivalent to turning an angle less than 180° in the opposite direction to the above setting, that is, the reverse rotation setting.

When between 180° and 360° (which can also be considered as between 0° and -180°), the rotation device and the support device may enter the acquisition range of the image acquisition device, which is not desirable. Therefore, a rod 6 can be added between the angle setting device and the image acquisition device, as shown in FIG. 4 , even if the image acquisition device, the support device and the rotation device are not in the same plane, and the distance is large, the acquisition range will not be blocked . It can be understood that the rod 6 can be a straight rod extending in a certain direction, or a curved rod extending in any three-dimensional space. In particular, the rod 6 can also be a length-adjustable rod. In addition, it can also be realized by changing the shape and structure of the support device. As shown in FIG. 5 , for example, the support device may be configured to resemble an inverted L shape, ie, comprising a vertical part connected to the rotating device and a lateral part connected to the angle setting device. Of course, the support device can also be in other complex shapes (for example, the support device extends along the Z axis, the Y axis, and the Z axis), so that the image acquisition device can be located at any position in space and deviate from the rotation axis of the device. Similarly, the support device can also be a displacement device that can freely adjust the position in both the XYZ axes, so that the image acquisition device can translate in the XYZ directions thereon.

It can be understood that the above-mentioned crossbar can be a telescopic device, that is, the extended length of the crossbar can be adjusted according to actual needs, so as to meet the needs of different target sizes or collection spaces. Moreover, although the carrying device 3 is used to carry the entire device at the lowermost part of the entire device in the figure, it is understood that the entire device can also be used upside down completely. Of course, the entire device does not have to be used vertically, and the entire device can be rotated by 90° so that the device can be used horizontally, or it can be used at any inclination angle, which can be selected according to actual needs.

When collecting the surface of the object, the image acquisition device can be set at a suitable angle as required. Usually, when the angle is set between 0° and 180°, it is suitable for collecting the object at the top or the top cover of the space; when the set angle is 90° When the angle is ～-90°, it is suitable for collecting objects located in the periphery, or the side wall of the space; when the angle is set between 0° and -180°, it is suitable for collecting the bottom object, or the bottom of the space.

The above-mentioned angle setting device is an adjustable rotating device, which is locked after being rotated to the set angle. The adjustable rotating device can be manually adjusted or automatically adjusted electrically. At the same time, it can also be a fixed angle device, that is, after the image acquisition device is installed on it, the optical axis direction naturally satisfies the set angle, and the fixation is not adjustable. In this way, in some known fixed use occasions, it is not necessary to adjust the set angle every time, so as to avoid inaccuracy caused by repeated adjustment.

Another embodiment of the present invention provides a tilt-adjustable intelligent visual 3D information acquisition device, please refer to FIG.

The image acquisition device 1 is disposed on the tilt device 41 , so that the image acquisition device 1 can tilt and rotate along the vertical plane. The pitching device 41 can be a roller, a gear, a bearing, a ball joint and the like. The optical axis of the image acquisition device 1 is usually parallel to the pitch direction, but may also be at a certain angle in some special cases. The pitching device 41 can be adjusted manually, or can be pitched and rotated under the driving of a motor, so as to realize precise pitch angle adjustment according to program control. The tilting device further includes a locking mechanism for locking the tilting device after the tilting angle is adjusted in place and the optical axis of the image capturing device is at a predetermined angle with the horizontal plane, thereby preventing it from rotating in the vertical direction again.

The pitching device 41 is connected with the rotating shaft of the rotating device 2, and is driven to rotate by the rotating device. Of course, the rotating shaft of the rotating device can also be connected to the pitching device through a reduction gear, for example, through a gear set or the like.

Due to the adjustment of the tilting device, the optical axis of the image acquisition device usually forms a certain angle with the horizontal plane. This allows scanning of targets whose surfaces are not perpendicular to the horizontal. That is, according to the approximate angle between the surface of the target object and the horizontal plane, the tilting device is adjusted so that the optical axis of the image acquisition device is perpendicular to the surface of the target object as much as possible, so as to improve the acquisition accuracy of the details of the target object. Of course, it can also be parallel to the horizontal plane in special cases.

Usually, the rotation axis or its extension line (ie, the rotation center line) passes through the image acquisition device, that is, the image acquisition device still rotates in an autorotation manner. This is essentially different from the acquisition method (surround type) in which the traditional image acquisition device rotates around a certain object, that is, it is completely different from the surround type in which the image acquisition device rotates around the target object. The optical collection ports (eg lenses) of the image collection device are all facing away from the direction of the rotation axis, that is to say, the collection area of the image collection device has no intersection with the rotation center line. At the same time, because the optical axis of the image acquisition device has an included angle with the horizontal plane, this method is also quite different from the general self-rotation method, especially the target object whose surface is not perpendicular to the horizontal plane can be collected.

The above-mentioned pitching device 41 generally satisfies that the image capturing device 1 can adjust the pitching angle thereon, and is fixed after being rotated in place, so that the pitching device 41 drives the image capturing device 1 to rotate. As shown in FIG. 7 , in some applications or products, the image capture device can be directly fixed at a specific angle of the pitch device that has been set, instead of having the function of adjustable angle. That is to say, the optical axis of the image capture device is directly tilted by a certain angle and fixed on the tilt device (for example, a bracket).

Of course, the rotating shaft of the rotating device in the above-mentioned acquisition device can also be connected to the image acquisition device through a deceleration device, for example, through a gear set or the like. When the image capturing device rotates 360° on the horizontal plane, it captures an image corresponding to the target at a specific position (the specific shooting position will be described in detail later). This shooting can be performed in synchronization with the rotation action, or after the shooting position stops rotating, and then continues to rotate after shooting, and so on. The above-mentioned rotating device may be a motor, a motor, a stepping motor, a servo motor, a micro motor, or the like. The rotating device (for example, various types of motors) can rotate at a specified speed under the control of the controller, and can rotate at a specified angle, so as to realize the optimization of the collection position. The specific collection position will be described in detail below. Of course, the rotating device in the existing equipment can also be used, and the image capturing device can be installed thereon.

In addition, the support device can also realize the translation relative to the rotation center in the XY plane, so as to realize more flexible acquisition.

The bearing device is used to carry the weight of the entire equipment, and the rotating device 2 is connected with the bearing device 3 . The carrying device may be a tripod, a base with a supporting device, or the like. Typically, the rotating device is located in the center part of the carrier to ensure balance. But in some special occasions, it can also be located in any position of the carrier. Furthermore, the carrying device is not necessary. The swivel device can be installed directly in the application, eg on the roof of a vehicle. The carrying device can also be a hand-held part, so that the 3D acquisition device can be used by hand.

The 3D information acquisition device may further include a ranging device, the ranging device is fixedly connected with the image acquisition device, and the pointing direction of the ranging device is the same as the direction of the optical axis of the image acquisition device. Of course, the distance measuring device can also be fixedly connected to the rotating device, as long as it can rotate synchronously with the image capturing device. Preferably, an installation platform may be provided, the image acquisition device and the distance measuring device are both located on the platform, the platform is installed on the rotating shaft of the rotating device, and is driven and rotated by the rotating device. The distance measuring device can use a variety of methods such as a laser distance meter, an ultrasonic distance meter, an electromagnetic wave distance meter, etc., or a traditional mechanical measuring tool distance measuring device. Of course, in some applications, the 3D acquisition device is located at a specific location, and its distance from the target has been calibrated, and no additional measurement is required.

The 3D information acquisition device may further include a light source, and the light source may be disposed around the image acquisition device, on the rotating device, and on the installation platform. Of course, the light source can also be set independently, for example, an independent light source is used to illuminate the target. Even when lighting conditions are good, no light source is used. The light source can be an LED light source or an intelligent light source, that is, the parameters of the light source are automatically adjusted according to the conditions of the target object and the ambient light. Normally, the light sources are distributed around the lens of the image capture device 1 in a distributed manner, for example, the light sources are ring-shaped LED lights around the lens. Because in some applications it is necessary to control the intensity of the light source. In particular, a diffuser device, such as a diffuser housing, can be arranged on the light path of the light source. Or directly use the LED surface light source, not only the light is softer, but also the light is more uniform. More preferably, an OLED light source can be used, which has a smaller volume, softer light, and has flexible properties, which can be attached to a curved surface.

In order to facilitate the measurement of the actual size of the target, multiple marking points can be set at the position of the target. And the coordinates of these marker points are known. By collecting marker points and combining their coordinates, the absolute size of the 3D composite model is obtained. These marking points can be pre-set points or laser light spots. The method for determining the coordinates of these points may include: ①Using laser ranging: using a calibration device to emit laser light toward the target to form a plurality of calibration point spots, and obtain the calibration point coordinates through the known positional relationship of the laser ranging unit in the calibration device. Use the calibration device to emit laser light toward the target, so that the light beam emitted by the laser ranging unit in the calibration device falls on the target to form a light spot. Since the laser beams emitted by the laser ranging units are parallel to each other, and the positional relationship between the units is known. Then the two-dimensional coordinates on the emission plane of the multiple light spots formed on the target can be obtained. By measuring the laser beam emitted by the laser ranging unit, the distance between each laser ranging unit and the corresponding light spot can be obtained, that is, depth information equivalent to multiple light spots formed on the target can be obtained. That is, the depth coordinates perpendicular to the emission plane can be obtained. Thereby, the three-dimensional coordinates of each spot can be obtained. ②Using the combination of distance measurement and angle measurement: measure the distance and the angle between multiple markers respectively to calculate the respective coordinates. ③ Use other coordinate measurement tools: such as RTK, global coordinate positioning system, star-sensing positioning system, position and pose sensors, etc.

3D information collection process

When collecting objects located at the top, or the top cover of the space, set the set angle to 0°～180°;

When collecting objects located in the periphery, or the side walls of the space, set the angle in the range of 90°～-90°;

When collecting the bottom object, or the bottom of the space, set the angle in the range of 0°～-180°.

The rotating device drives the image acquisition device to rotate at a certain speed, and the image acquisition device performs image acquisition at a set position during the rotation process. At this time, the rotation may not be stopped, that is, the image acquisition and the rotation are performed synchronously; or the rotation may be stopped at the position to be acquired, image acquisition is performed, and the rotation continues to the next position to be acquired after the acquisition is completed. The rotating device can be driven by a pre-programmed control unit program. It can also communicate with the upper computer through the communication interface, and control the rotation through the upper computer. In particular, it can also be wired or wirelessly connected to the mobile terminal, and the rotation of the rotating device can be controlled by the mobile terminal (eg, a mobile phone). That is, the rotation parameters of the rotating device can be set through the remote platform, cloud platform, server, host computer, and mobile terminal to control the start and stop of its rotation.

The image acquisition device collects multiple images of the target, and sends the images to the remote platform, cloud platform, server, host computer and/or mobile terminal through the communication device, and uses the 3D model synthesis method to perform 3D synthesis of the target.

In particular, the distance measuring device can be used to measure the corresponding distance parameters in the relevant formula conditions, that is, the distance from the rotation center to the target, and the distance from the sensing element to the target, before or at the same time as the acquisition. The collection position is calculated according to the corresponding conditional formula, and the user is prompted to set the rotation parameters, or the rotation parameters are automatically set.

When measuring the distance before acquisition, the rotating device can drive the distance measuring device to rotate, so as to measure the above two distances at different positions. The two distances measured at multiple measurement points are averaged respectively, and are brought into the formula as the unified distance value collected this time. The average value may be obtained by a summation average method, a weighted average method, or another average value method, or a method of discarding abnormal values and averaging again.

When the distance measurement is performed during the acquisition process, while the rotating device is rotated to the first position for image acquisition, the above-mentioned two distance values are measured, and they are brought into the conditional formula to calculate the interval angle, and the next step is determined according to the angle. Collection location.

Optimization of camera position

In order to ensure that the device can take into account the effect and efficiency of 3D synthesis, in addition to the conventional method of optimizing the synthesis algorithm, the method of optimizing the camera acquisition position can also be adopted. Especially when the acquisition direction of the camera of the 3D acquisition and synthesis device deviates from the direction of its rotation axis, the prior art for such a device does not mention how to better optimize the camera position. Even if some optimization methods exist, they are obtained under different empirical conditions under different experiments. In particular, some existing position optimization methods need to obtain the size of the target object, which is feasible in surround 3D acquisition and can be measured in advance. However, it is difficult to measure in advance in an open space. Therefore, it is necessary to propose a method for optimizing the camera position when the acquisition direction of the camera of the 3D acquisition and synthesis device and the direction of its rotation axis deviate from each other. This is exactly the problem to be solved by the present invention and the technical contribution made.

To this end, the present invention conducts a large number of experiments, and summarizes the following empirical conditions that the interval of camera acquisition is preferably satisfied during acquisition.

When performing 3D acquisition, the included angle α of the optical axis of the image acquisition device at two adjacent positions satisfies the following conditions:

in,

R is the distance from the center of rotation to the surface of the target,

T is the sum of the object distance and the image distance during acquisition, that is, the distance between the photosensitive unit of the image acquisition device and the target object.

d is the length or width of the photosensitive element (CCD) of the image acquisition device. When the above two positions are along the length direction of the photosensitive element, d is the length of the rectangle; when the above two positions are along the width direction of the photosensitive element, d is the rectangle. width.

F is the focal length of the lens of the image acquisition device.

u is the empirical coefficient.

Usually, a distance measuring device, such as a laser distance meter, is configured on the acquisition device. Adjust its optical axis to be parallel to the optical axis of the image acquisition device, then it can measure the distance from the acquisition device to the surface of the target object. Using the measured distance, according to the known positional relationship between the distance measuring device and the various components of the acquisition device, you can Get R and T.

When the image acquisition device is in any one of the two positions, the distance from the photosensitive element to the surface of the target object along the optical axis is taken as T. In addition to this method, multiple averaging methods or other methods can also be used. The principle is that the value of T should not deviate from the distance between the image and the object during acquisition.

In the same way, when the image acquisition device is in any one of the two positions, the distance from the center of rotation to the surface of the target object along the optical axis is taken as R. In addition to this method, multiple averaging methods or other methods can also be used, the principle of which is that the value of R should not deviate from the radius of rotation at the time of acquisition.

Usually, the size of the object is used as a method for estimating the position of the camera in the prior art. Because the size of the object will change with the change of the measured object. For example, after collecting 3D information of a large object, when collecting small objects, it is necessary to re-measure the size and re-calculate. The above-mentioned inconvenient measurements and multiple re-measurements will bring about measurement errors, resulting in incorrect camera position estimation. In this scheme, based on a large number of experimental data, the empirical conditions that the camera position needs to meet are given, and there is no need to directly measure the size of the object. In the empirical conditions, d and F are fixed parameters of the camera. When purchasing a camera and lens, the manufacturer will give the corresponding parameters without measurement. However, R and T are only a straight line distance, which can be easily measured by traditional measurement methods, such as straightedge and laser rangefinder. At the same time, in the apparatus of the present invention, the acquisition direction of the image acquisition device (eg, camera) is away from the direction of its rotation axis, that is, the orientation of the lens is generally opposite to the rotation center. In this case, it is easier to control the angle α of the optical axis between the two positions of the image acquisition device, and it is only necessary to control the rotation angle of the rotary drive motor. Therefore, it is more reasonable to use α to define the optimal position. Therefore, the empirical formula of the present invention makes the preparation process convenient and quick, and also improves the arrangement accuracy of the camera position, so that the camera can be set in an optimized position, thereby taking into account the 3D synthesis accuracy and speed at the same time.

According to a large number of experiments, in order to ensure the speed and effect of synthesis, u should be less than 0.498. For better synthesis effect, u<0.411 is preferred, especially u<0.359. In some applications, u<0.250, or u<0.214, or u<0.191, or u<0.068, or u<0.048.

Using the device of the present invention, experiments are carried out, and some experimental data are as follows, in mm. (The following data are only limited examples)

When the camera angle is set to 0°,

When the camera setting angle is not 0

The above data are only obtained from experiments to verify the conditions of the formula, and do not limit the invention. Even the absence of these data does not affect the objectivity of the formula. Those skilled in the art can adjust the parameters of the equipment and the details of the steps to conduct experiments, and other data obtained are also in line with the conditions of the formula.

3D model synthesis method

The multiple images acquired by the image acquisition device are sent to the processing unit, and the following algorithm is used to construct a 3D model. The processing unit may be located in the acquisition device, or may be located remotely, such as a cloud platform, a server, a host computer, and the like.

The specific algorithm mainly includes the following steps:

Step 1: Perform image enhancement processing on all input photos. The following filters are used to enhance the contrast of the original photo and suppress noise at the same time.

In the formula: g(x, y) is the gray value of the original image at (x, y), f(x, y) is the gray value of the original image after enhancement by Wallis filter, and m _g is the local gray value of the original image. sg is the local grayscale standard deviation of the original image, _mf is the local _grayscale target value of the transformed image, and _sf is the localized grayscale standard deviation target value of the transformed image. c∈(0,1) is the expansion constant of the image variance, and b∈(0,1) is the image luminance coefficient constant.

The filter can greatly enhance the image texture patterns of different scales in the image, so it can improve the number and accuracy of feature points when extracting image point features, and improve the reliability and accuracy of matching results in photo feature matching.

Step 2: Extract feature points from all the input photos, and perform feature point matching to obtain sparse feature points. The SURF operator is used to extract and match the feature points of the photo. The SURF feature matching method mainly includes three processes, feature point detection, feature point description and feature point matching. This method uses Hessian matrix to detect feature points, uses Box Filters to replace second-order Gaussian filtering, uses integral image to accelerate convolution to improve calculation speed, and reduces the dimension of local image feature descriptors, to speed up matching. The main steps include ① constructing the Hessian matrix to generate all interest points for feature extraction. The purpose of constructing the Hessian matrix is to generate image stable edge points (mutation points); ② constructing the scale space feature point positioning, which will be processed by the Hessian matrix Each pixel point is compared with 26 points in the two-dimensional image space and scale space neighborhood, and the key points are initially located. (3) The main direction of the feature point is determined by using the harr wavelet feature in the circular neighborhood of the statistical feature point. That is, in the circular neighborhood of the feature points, the sum of the horizontal and vertical harr wavelet features of all points in the 60-degree sector is counted, and then the sector is rotated at intervals of 0.2 radians, and the harr wavelet eigenvalues in the region are counted again. The direction of the sector with the largest value is used as the main direction of the feature point; (4) a 64-dimensional feature point description vector is generated, and a 4*4 rectangular area block is taken around the feature point, but the direction of the obtained rectangular area is along the main direction of the feature point. direction. Each sub-region counts the haar wavelet features of 25 pixels in the horizontal and vertical directions, where the horizontal and vertical directions are relative to the main direction. The haar wavelet features are 4 directions after the horizontal value, after the vertical value, after the absolute value of the horizontal direction and the sum of the absolute value of the vertical direction. These 4 values are used as the feature vector of each sub-block area, so there are 4* 4*4=64-dimensional vector as the descriptor of the Surf feature; ⑤ Matching of feature points, the matching degree is determined by calculating the Euclidean distance between the two feature points. The shorter the Euclidean distance, the better the matching degree of the two feature points. .

Step 3: Input the coordinates of the matched feature points, and use the beam method to adjust the position and attitude data of the sparse target object 3D point cloud and the camera to obtain the sparse target object model 3D point cloud and position model coordinates. ; Take sparse feature points as the initial value, perform dense matching of multi-view photos, and obtain dense point cloud data. There are four main steps in this process: stereo pair selection, depth map calculation, depth map optimization, and depth map fusion. For each image in the input dataset, we select a reference image to form a stereo pair for computing the depth map. So we can get a rough depth map for all images, these depth maps may contain noise and errors, and we use its neighborhood depth map to perform a consistency check to optimize the depth map for each image. Finally, depth map fusion is performed to obtain a 3D point cloud of the entire scene.

Step 4: Use dense point cloud to reconstruct the target surface. Including several processes of defining octrees, setting function spaces, creating vector fields, solving Poisson equations, and extracting isosurfaces. The integral relationship between the sampling point and the indicator function is obtained from the gradient relationship, the vector field of the point cloud is obtained according to the integral relationship, and the approximation of the gradient field of the indicator function is calculated to form the Poisson equation. According to the Poisson equation, the approximate solution is obtained by matrix iteration, the isosurface is extracted by the moving cube algorithm, and the model of the measured object is reconstructed from the measured point cloud.

Step 5: Fully automatic texture mapping of the target model. After the surface model is constructed, texture mapping is performed. The main process includes: ① texture data acquisition through image reconstruction of the target surface triangular mesh; ② visibility analysis of the reconstructed model triangle. Use the calibration information of the image to calculate the visible image set of each triangular face and the optimal reference image; 3. The triangular face is clustered to generate texture patches. According to the visible image set of the triangular surface, the optimal reference image and the neighborhood topology relationship of the triangular surface, the triangular surface is clustered into several reference image texture patches; ④The texture patches are automatically sorted to generate texture images. Sort the generated texture patches according to their size relationship, generate a texture image with the smallest enclosing area, and obtain the texture mapping coordinates of each triangular surface.

It should be noted that the above algorithm is the algorithm used in the present invention, the algorithm cooperates with the image acquisition conditions, and the time and quality of synthesis are taken into account when using this algorithm. However, it can be understood that conventional 3D synthesis algorithms in the prior art can also be used in conjunction with the solution of the present invention.

Applications

In order to construct the overall 3D model of the engine, 3D modeling of its outer surface and the interior of the inner cavity is required. When modeling the outer surface, the angle is set to 180°, and the acquisition is performed by rotation to obtain multiple images. When modeling the surface of the lumen, the angle was set to 10°, and a device with a micro-camera mounted on the rod was inserted into the lumen to take pictures by rotating to obtain multiple images. The 3D model of the outer surface and inner cavity of the engine is synthesized by two parts of the image, so as to realize the quality inspection of the inner cavity of the engine.

In order to build a 3D model of the inner cavity of the workpiece with a conical deep hole, a device with a micro camera installed on the rod can be inserted into the inner cavity to take pictures by rotating, and the 3D model of the inner cavity of the workpiece can be synthesized by using the photos, so as to realize the inner cavity of the workpiece. quality check.

The above-mentioned target object, target object, and object all represent objects for which three-dimensional information is pre-acquired. It can be a solid object, or it can be composed of multiple objects. For example, it can be a building, a part, or the like. The 3D information of the target includes a 3D image, a 3D point cloud, a 3D mesh, a local 3D feature, a 3D size and all parameters with the 3D feature of the target. The so-called three-dimensional in the present invention refers to having three directional information of XYZ, especially having depth information, which is essentially different from having only two-dimensional plane information. It is also fundamentally different from some definitions that are called three-dimensional, panoramic, holographic, and three-dimensional, but actually only include two-dimensional information, especially not depth information.

The acquisition area mentioned in the present invention refers to the range that can be photographed by an image acquisition device (eg, a camera). The image acquisition device in the present invention can be CCD, CMOS, camera, video camera, industrial camera, monitor, camera, mobile phone, tablet, notebook, mobile terminal, wearable device, smart glasses, smart watch, smart bracelet and Image acquisition capabilities for all devices.

In the description provided herein, numerous specific details are set forth. It will be understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it is to be understood that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, figure, or its description. However, this disclosure should not be construed as reflecting an intention that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

Those skilled in the art will appreciate that the modules in the device in the embodiment can be adaptively changed and arranged in one or more devices different from the embodiment. The modules or units or components in the embodiments may be combined into one module or unit or component, and further they may be divided into multiple sub-modules or sub-units or sub-assemblies. All features disclosed in this specification (including accompanying claims, abstract and drawings) and any method so disclosed may be employed in any combination unless at least some of such features and/or procedures or elements are mutually exclusive. All processes or units of equipment are combined. Each feature disclosed in this specification (including accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, it will be understood by those skilled in the art that although some of the embodiments herein include certain features, but not others, included in other embodiments, that combinations of features of the different embodiments are intended to be within the scope of the present invention And form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

Various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all functions of some or all of the components in the apparatus according to the present invention according to the embodiments of the present invention. The present invention can also be implemented as apparatus or apparatus programs (eg, computer programs and computer program products) for performing part or all of the methods described herein. Such a program implementing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such signals may be downloaded from Internet sites, or provided on carrier signals, or in any other form.

It should be noted that the above-described embodiments illustrate rather than limit the invention, and that alternative embodiments may be devised by those skilled in the art without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. do not denote any order. These words can be interpreted as names.

By now, those skilled in the art will recognize that although various exemplary embodiments of the present invention have been shown and described in detail herein, the present invention may still be implemented in accordance with the present disclosure without departing from the spirit and scope of the present invention. The content directly determines or derives many other variations or modifications consistent with the principles of the invention. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

A visual 3D information acquisition device, characterized in that it includes an image acquisition device, a rotation device, a support device and an angle setting device;

The rotating device drives the supporting device to rotate;

An angle setting device and an image acquisition device are arranged on the support device;

The angle setting device is used to set the pitch angle between the optical axis of the image acquisition device and the rotation plane;

During the rotation process of the image acquisition device, the included angle α of the optical axes of two adjacent acquisition positions satisfies the following conditions:

Among them, R is the distance from the rotation center to the surface of the target object, T is the sum of the object distance and the image distance during acquisition, d is the length or width of the photosensitive element of the image acquisition device, F is the lens focal length of the image acquisition device, and u is the experience coefficient.
The apparatus of claim 1, wherein: u<0.498, or u<0.411, or u<0.359, or u<0.250, or u<0.214, or u<0.191, or u<0.068, or u< 0.048.
The device according to claim 1, wherein the set included angle can be in the range of 0°～180°, 90°～-90°, 0°～-180°.
The apparatus of claim 1, wherein the image acquisition device translates relative to the rotational plane.
The device according to claim 1, wherein the set angle is 20°, 40°, 60°, 80°, 90°, 100°, 120°, 160°, 180°.
The apparatus of claim 1, wherein the angle setting device is an adjustable angle setting device.
The apparatus of claim 1, wherein the angle setting device is a fixed angle setting device.
The device of claim 1, wherein the supporting device comprises a translation unit, so that the image capturing device is deviated from the center of rotation of the device.
The device according to claim 1, wherein the supporting device makes the image capturing device located at any point in space and deviated from the rotation center of the device.
A 3D synthesis or identification device, characterized in that it comprises the device according to any one of the above claims 1-9.
A 3D synthesis or identification method, characterized in that it comprises the device according to any one of the above claims 1-9.
A device for manufacturing or displaying objects, characterized in that it comprises the equipment according to any one of the above claims 1-9.
A method for manufacturing or displaying an object, characterized in that it comprises the device according to any one of the above claims 1-9.
A visual 3D information acquisition device, characterized in that it includes an image acquisition device, a rotation device, a carrying device and a pitching device;

The image capturing device is arranged on the pitching device, so that the image capturing device can pitch and rotate along the vertical plane;

The pitching device is connected with the rotating device, and the rotating device drives it to rotate;

The angle α between the optical axes of the image acquisition device at two adjacent acquisition positions satisfies the following conditions:

Among them, R is the distance from the rotation center to the surface of the target object, T is the sum of the object distance and the image distance during acquisition, d is the length or width of the photosensitive element of the image acquisition device, F is the lens focal length of the image acquisition device, and u is the experience coefficient.
The apparatus of claim 14, wherein: u<0.498, or u<0.411, or u<0.392, or u<0.296, or u<0.202, or u<0.041, or u<0.028.
The device of claim 14, wherein the pitching device is manually adjusted or driven by a motor.
The device according to claim 14, wherein the tilting device is a fixed bracket, so that the optical axis of the image capturing device can form a certain angle with the rotation plane.
The device according to claim 14, wherein the optical acquisition ports of the image acquisition device are all facing away from the direction of the rotation axis.
The device according to claim 14, characterized in that: it further comprises a distance measuring device, and the distance measuring device rotates synchronously with the image acquisition device.
The device according to claim 14, wherein a plurality of marking points are set at the position of the target object.
15. The apparatus of claim 14, wherein the pitching device further comprises a locking mechanism.
A 3D synthesis identification device, characterized in that it includes the device described in any of the above claims 14-21.
An object manufacturing display device, characterized in that it comprises the equipment according to any of the above claims 14-21.