CN108318007B - A shooting method of stitched aerial oblique photography - Google Patents

Abstract

The present invention provides a shooting method for splicing aerial oblique photography. The shooting method includes the following steps: S1. The aircraft reaches a preset shooting position, and by rotating the first cabin body, a plurality of two inclined cameras in the first cabin body is completed. Angle shooting; S2, complete the shooting of multiple angles of the two inclined cameras in the second cabin by rotating the second cabin; S3, complete the shooting of the remaining preset positions, the stitched images shot at the adjacent preset positions overlap between them; at the same preset shooting position, two tilt cameras in the first cabin and two tilt cameras in the second cabin overlap each other with images captured at adjacent angles. The whole shooting method of the invention is simple and reliable, the shooting accuracy is high, the requirement for tilting the camera is low, and multi-angle free shooting is realized; the expanded stitched image obtained by the shooting method is convenient for post-processing, and is beneficial to improve the efficiency of later modeling and model accuracy.

Description

A shooting method of stitched aerial oblique photography

technical field

The invention relates to a shooting method for splicing aerial oblique photography.

Background technique

The aerial panoramic oblique photography device belongs to the technical category of aerial photogrammetry and aerial oblique photography. Aerial photogrammetry is based on aerial photography and the use of photogrammetry technology to produce a variety of surveying and mapping products, including digital ground models, orthophoto maps, and line maps. Aerial oblique photogrammetry is to obtain the side texture of ground objects by shooting oblique images, and then establish a real three-dimensional model of the city through the technology of photogrammetry.

Aerial oblique photography is a breakthrough of traditional aerial photogrammetry. Through the combination of cameras with different perspectives, it can shoot natural objects and artificial buildings on the ground. The existing aerial oblique photographing device generally adopts the form of a combination of five cameras, including one downward-looking camera and four oblique cameras. Due to the large number of cameras, when considering the volume and weight of the system, the designed tilt camera generally adopts a commercial medium-format camera or a full-frame camera.

Chinese Patent No. 2017100622249 discloses an aerial panoramic oblique photographing device, comprising a pod body, on which at least two downward-looking cameras and a plurality of tilting cameras are arranged, and the at least two downward-looking cameras are arranged laterally , and the shooting areas of adjacent downward looking cameras among the at least two downward looking cameras partially overlap.

Chinese patent 2014800800293 discloses a system for capturing aerial images, the system includes at least one panoramic camera, a plurality of detail cameras, and a frame for supporting the cameras, each detail camera has a longer focal length than at least one panoramic camera, and each detail camera has a longer focal length than the at least one panoramic camera. The detail cameras are mounted at different angles in the lateral direction so that the fields of view of the detail cameras overlap to form an extended lateral field of view, and the frame can be attached to the aircraft floor above the camera holes, thereby providing the cameras under the aircraft through the camera holes view of the ground.

Chinese Patent No. 201010562117.0 discloses a splicing imaging system based on the principle of shifting axis, including at least one imaging lens, the at least one imaging lens is arranged on the same plane, and has the same focal length and field of view; at least one imaging device in the focal plane of an imaging lens; wherein each said imaging lens is arranged with its optical axis perpendicular to its focal plane, and each said imaging device is arranged with a preset in its focal plane amount of axis shift.

The disadvantage of the prior art is that the currently used aerial oblique photographing devices generally use multiple built-in cameras, and by placing them at different angles, shooting at multiple angles is realized to obtain panoramic images of the ground. The number of required built-in cameras is large, the volume and weight of the photographing device are large, and the cost is high.

Therefore, how to provide a photographing method of an oblique photographing system with wide application range and high efficiency has become a problem that needs to be solved in the industry.

SUMMARY OF THE INVENTION

Aiming at the defects of the prior art, the present invention provides a splicing aerial oblique photographing method, wherein adjacent photographed images overlap each other, with high positioning accuracy, high photographing efficiency, and realizing multi-angle free photographing.

In order to achieve the above purpose, the present invention provides a spliced aerial oblique photography shooting method, wherein a first cabin body and a second cabin body are provided in the loading compartment, the first cabin body is provided with two tilt cameras, and the first cabin body is provided with two tilt cameras. The second cabin is equipped with two tilt cameras, and the four tilt cameras are installed at different angles, so that the fields of view of the four tilt cameras overlap each other in the same shooting area to form a stitched image; the shooting methods include the following step:

S1. The aircraft reaches the preset shooting position, and by rotating the first cabin body, the shooting of multiple angles of the two inclined cameras in the first cabin body is completed;

S2. By rotating the second cabin, shooting at multiple angles of the two inclined cameras in the second cabin is completed;

S3. The shooting of the remaining preset positions is completed, and the stitched images shot at adjacent preset positions are overlapped;

At the same preset shooting position, the images captured by the two tilt cameras in the first cabin and the two tilt cameras in the second cabin overlap with each other at adjacent angles.

The present invention further drives the inclined camera in the first cabin and the inclined camera in the second cabin to take pictures by rotating the first cabin and the second cabin, so as to obtain matrix images; They overlap each other to form an extended stitched image, and the coverage area of the stitched image is large, which can greatly improve the shooting efficiency and save the shooting time.

According to another specific embodiment of the present invention, the two inclined cameras in the first cabin complete the shooting of 6 angles; the two inclined cameras in the second cabin complete the shooting in 6 angles; and 12 are completed at the preset position Shooting at an angle to obtain a stitched image of three rows and four columns or four rows and three columns.

According to another specific embodiment of the present invention, step S1 includes:

Rotate the first rotation axis of the first cabin to the first inclination angle, and shoot, and the two cameras of the first cabin obtain an image of the first viewing angle;

Rotate the first rotating shaft to the second angle of inclination to shoot, and the two cameras of the first cabin obtain the image of the second angle of view;

Rotate the first rotating shaft to the third angle of inclination to shoot, and the two cameras of the first cabin obtain the image of the third angle of view.

In this solution, among the images between the first angle of view, the second angle of view, and the third angle of view, the adjacent images overlap each other, that is, between the adjacent inclination angles between the first angle of view, the second angle of inclination, and the third angle of inclination There is a certain degree of occlusion, and the shooting position of the camera has a partial overlap of the field of view. Wherein, the first rotating shaft is provided with a steering gear or other similar driving components, such as a transmission rod structure, etc., to drive the first rotating shaft to drive the first cabin to swing.

According to another specific embodiment of the present invention, the two tilt cameras in the first cabin are symmetrically arranged along the direction perpendicular to the first rotation axis, and the included angle between the two tilt cameras is 15°-30°.

According to another specific embodiment of the present invention, step S2 includes:

Rotate the second rotating shaft of the second cabin to the fourth inclination angle to shoot, and the two cameras of the second cabin obtain the image of the fourth angle of view;

Rotate the second rotating shaft to the fifth angle of inclination to shoot, and the two cameras of the second cabin obtain the image of the fifth angle of view;

Rotate the second rotating shaft to the sixth inclination angle to shoot, and the two cameras of the second cabin obtain the image of the sixth angle of view.

In this solution, among the images between the fourth viewing angle, the fifth viewing angle, and the sixth viewing angle, the adjacent images overlap each other, that is, the adjacent inclination angles between the fourth, fifth, and sixth inclination angles There is a certain degree of occlusion, and the shooting position of the camera has a partial overlap of the field of view. Wherein, the first rotating shaft is provided with a steering gear or other similar driving components, such as a transmission rod structure, etc., to drive the first rotating shaft to drive the first cabin to swing.

According to another specific embodiment of the present invention, the two tilt cameras in the second cabin are symmetrically arranged along the direction perpendicular to the second rotation axis, and the included angle between the two tilt cameras is: 60°-90°.

According to another specific embodiment of the present invention, the first rotating shaft and the second rotating shaft are arranged parallel to each other. In this scheme, the four tilt cameras are arranged in the shape of a field to ensure that the center of gravity of the four tilt cameras is consistent with the center of gravity of the aircraft, so that the shooting process is more stable.

According to another specific embodiment of the present invention, the first viewing angle and the fourth viewing angle are downward viewing angles, and the downward viewing angles are coincident with the vertical plane; The angle between the inclination angles is: 30°—45°, the angle between the fifth inclination angle and the fourth inclination angle is: 30°—45°; The angle between the inclination angles is: 30°-45°, and the angle between the sixth inclination angle and the first inclination angle is: 30°-45°. Preferably, the forward viewing angle, the downward viewing angle, and the rear viewing angle are distributed at intervals, that is, the included angles between the forward viewing angle and the downward viewing angle, and the rear viewing angle and the downward viewing angle are the same.

According to another specific embodiment of the present invention, the lenses of the four tilt cameras are fixed-focus lenses, and the focal length is 20mm-150mm, which can be specifically selected from: 20mm, 21mm, 22mm, 24mm, 25mm, 28mm, 30mm, 32mm, 35mm , 40mm, 50mm, 55mm, 58mm, 60mm, 85mm, 90mm, 100mm, 105mm, 135mm, 150mm; in this scheme, the focal length of the tilt camera is selected according to the flying height, the required accuracy requirements and other conditions.

According to another specific embodiment of the present invention, images captured at adjacent angles have an overlap of 10%-15%. The images captured by adjacent tilt cameras overlap each other, which can improve the definition of the expanded stitched image, which is beneficial to image stitching and post-processing.

According to another specific embodiment of the present invention, twelve tilt cameras are arranged in the loading compartment, and the twelve tilt cameras are distributed in three rows and four columns or four rows and three columns, and the adjacent tilt cameras are all arranged in different The same shooting area of the twelve tilting cameras overlaps each other to form a stitched image; the shooting method includes: the control module controls the twelve tilting cameras to complete the shooting of multiple preset positions in sequence; There is overlap between the extended stitched images taken between the preset positions.

In the present invention, the rotation angles of the first rotating shaft and the second rotating shaft are the same, the rotation range of the first cabin covers three continuous shooting areas, and the rotation range of the second cabin covers three continuous shooting areas, so that the At the same shooting position, the first cabin body and the second cabin body can be rotated twice to complete the image acquisition of twelve shooting areas to form an extended stitched image.

In the present invention, there is overlap between the expanded stitched images obtained from adjacent shooting areas, and the overlap degree is 70%-90%, and this overlap degree range can meet the modeling requirements of most target areas. According to the complexity of the target area, a small overlap ratio should be selected as much as possible to improve the shooting efficiency. For example, 70% overlap rate is selected for aerial oblique photography where the target area is sparse low-rise buildings, and 90% overlap rate is selected for aerial oblique photography where the target area is dense high-rise buildings.

The images obtained by the oblique photography shooting method provided by the present invention have high image cleanliness and high modeling accuracy, can be widely used in various fields such as land management, urban planning, urban management and construction, etc. The workload in the field can meet the needs of basic spatial information data in a large range, full coverage, and high accuracy.

Compared with the prior art, the advantages of the present invention are:

1. Through the position switching of four tilting cameras, a matrix-type extended stitching image is obtained. The shooting area of the same position is large, the shooting efficiency is high, and the shooting time is saved;

2. The whole shooting method is simple and reliable, the shooting accuracy is high, the requirement for tilting the camera is low, and multi-angle free shooting is realized;

3. The expanded stitched image obtained by the shooting method is convenient for post-processing, which is beneficial to improve the efficiency of post-modeling and the accuracy of the model.

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Description of drawings

1 is a schematic flowchart of the photographing method of Embodiment 1;

2 is a schematic diagram of a spliced image obtained by the shooting method of Embodiment 1;

3 is a schematic diagram of the overall structure of a photographing system that completes the photographing method of Embodiment 1;

Fig. 4 is the bottom view of Fig. 3;

Fig. 5 is the partial structure schematic diagram of Fig. 3;

Fig. 6 is the structural representation of the first cabin in Fig. 3;

FIG. 7 is a schematic structural diagram of the second cabin in FIG. 3 .

Detailed ways

Example 1

This embodiment provides a shooting method for stitched aerial oblique photography, as shown in Figures 1-2, to achieve twelve angles of shooting at preset positions, so as to obtain a stitched image with four rows and three columns. The shooting method includes: Follow the steps below:

S1: The aircraft reaches the preset shooting position, and by rotating the first cabin, the six-angle shooting of the two tilt cameras in the first cabin is completed; the specific implementation process is: rotating the first rotating shaft of the first cabin to the first Inclination, take pictures, the two cameras of the first cabin obtain the image of the first angle of view; rotate the first rotation axis to the second inclination angle, take pictures, the two cameras of the first cabin obtain the image of the second angle of view; rotate the first Rotate the axis to the third inclination angle to shoot, and the two cameras of the first cabin obtain the image of the third angle of view.

S2: By rotating the second cabin, the six-angle shooting of the two inclined cameras in the second cabin is completed; the specific implementation process is: rotating the second rotating shaft of the second cabin to the fourth inclination angle, shooting, and the second The two cameras of the cabin obtain the image of the fourth angle of view; rotate the second rotation axis to the fifth angle of inclination to shoot, and the two cameras of the second cabin obtain the image of the fifth angle of view; rotate the second axis of rotation to the sixth angle of inclination to perform To shoot, two cameras in the second pod acquire images from a sixth perspective.

S3: The shooting of the remaining preset positions is completed, and the stitched images shot at the adjacent preset positions overlap; wherein, the stitched images shot at the adjacent preset positions overlap with each other, and the overlap degree is 85%.

As shown in Figure 2, the flight direction is shown by the arrows in the figure, wherein the first and fourth viewing angles are downward viewing angles, and the downward viewing angles are coincident with the vertical plane; the second and fifth viewing angles are left viewing angles, and the third The third angle and the sixth angle are the right angle. Twelve images are taken at the same position, and the twelve images are distributed in four rows and three columns relative to the flight direction, and there is overlap between the obtained adjacent images, such as 10% overlap, between adjacent images. By overlapping each other, the definition of the expanded spliced image can be improved, which is beneficial to image splicing and post-processing.

A photographing system implementing the above photographing method, as shown in Figs.

Among them, the stowage compartment 1 is detachably connected to the aircraft, and the stowage compartment 1 is provided with a connector 11, a supporting frame 12, and a top carrier plate 13, and the connector 11 is arranged above the top carrier plate 13 for quickly realizing the The connection of the aircraft; the support frame 12 is arranged below the top carrier plate 13 , and the control module 5 is arranged on the top carrier plate 13 .

The photographing mechanism 2 is set on the support frame 12, which includes four tilt cameras, which can be interchanged between the four tilt cameras. According to the different areas to be operated, the focal length and accuracy of the four tilt cameras are determined. For example, the flying height is 135m, Use a tilt camera with a focal length of 35mm. Each tilting camera is installed at different angles, so that multiple tilting cameras overlap each other between the shooting areas at the preset positions to form an expanded stitched image; wherein, the four tilting cameras are the first camera 21, the third Two cameras 22 , a third camera 23 , and a fourth camera 24 .

As shown in FIG. 3 , the support frame 12 is provided with a first cabin body 3 and a second cabin body 4 , the first camera 21 and the second camera 22 are fixed in the first cabin body 3 , and the first cabin body 3 can surround the first cabin body 3 . A rotating shaft 141 swings continuously, and a first opening 142 is provided at the bottom of the first cabin body 3 , which can provide the first camera 21 and the second camera 22 with a field of view space required for shooting. The third camera 23 and the fourth camera 24 are fixed in the second cabin 4 , the second cabin 4 can swing continuously around the second rotating shaft 151 , and a second opening 152 is provided at the bottom of the second cabin 4 , which can The third camera 23 and the fourth camera 24 are provided with a field of view space required for shooting. Among them, the first steering gear 143 is provided on the first rotating shaft 141, and the second steering gear 153 is arranged on the second rotating shaft 151. The first steering gear 143 and the second steering gear 153 are both installed on the support frame 12, in order to keep the rotation Bearings are provided at the positions where the first rotating shaft 141 and the second rotating shaft 151 are connected with the support frame 12 to reduce the friction during the rotating process, and the first steering gear 143 and the second steering gear 143 and the second steering gear 143 and the second steering gear are controlled by the control module 5. The steering gear 153 is rotated, thereby realizing the change of the inclination angles of the four tilt cameras in the first cabin 3 and the second cabin 4 .

The layout of the first camera 21 and the second camera 22 is shown in FIG. 6 , the first camera 21 and the second camera 22 are symmetrical with respect to the central axis L1, and the angle between the optical axis G1 of the first camera 21 and the central axis L1 is 11 °, the angle between the optical axis G2 of the second camera 22 and the central axis L1 is also 11°.

The layout of the third camera 23 and the fourth camera 24 is shown in FIG. 7 . The third camera 23 and the fourth camera 24 are symmetrical with respect to the central axis L2 , wherein the central axis L1 and the central axis L2 are both perpendicular to the flight direction of the aircraft. In the vertical plane D1, the central axis L1 and the central axis L2 are parallel to each other. The included angle between the optical axis G3 of the third camera 23 and the central axis L2 is 33°, and the included angle between the optical axis G4 of the fourth camera 24 and the central axis L2 is also 33°.

In this photography system, the rotation angles of the first rotating shaft and the second rotating shaft are the same, the rotation range of the first cabin covers three continuous shooting areas, and the rotation range of the second cabin covers three continuous shooting areas, so Realize that in the same shooting position, the first cabin body and the second cabin body can be rotated twice to complete the image acquisition of twelve shooting areas, so as to form an extended stitched image. When shooting at the same position (the same position here does not mean that the aircraft stops flying, but the shooting interval between the first camera and the second camera is small, the distance traveled by the aircraft can be ignored, and the aircraft flies at a constant speed throughout the shooting process) , the first camera and the second camera shoot six images corresponding to the middle two rows of FIG. 1 , and the third camera and the fourth camera shoot six images corresponding to the upper and lower rows of FIG. 1 .

In the photographing system, the control module is connected to the four tilt cameras in communication, so as to control the tilt cameras to shoot, and under the control of the control module, the stitched image acquisition of multiple preset shooting positions within the preset route is completed.

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the scope of implementation of the present invention. Any person of ordinary skill in the art can make some improvements without departing from the scope of the present invention, that is, all equivalent improvements made according to the present invention should be covered by the scope of the present invention.

Claims (9)

1. A shooting method of spliced aerial oblique photography is characterized in that a mounting cabin is provided with a first cabin body and a second cabin body, the first cabin body is provided with two oblique cameras, the second cabin body is provided with two oblique cameras, and the four oblique cameras are all installed at different angles, so that the view fields of the four oblique cameras are mutually overlapped in the same shooting area to form a spliced image;

the shooting method comprises the following steps:

s1, when the aircraft reaches a preset shooting position, shooting of the two oblique cameras in the first cabin at multiple angles is completed by rotating the first cabin;

s2, completing shooting of the two oblique cameras in the second cabin at multiple angles by rotating the second cabin;

s3, shooting of the residual preset positions is completed, and spliced images shot at adjacent preset positions are overlapped, wherein the overlapping degree is 70% -90%;

in the same preset shooting position, 10% -15% of overlapping is formed between images shot at adjacent angles of the two oblique cameras in the first cabin body and the two oblique cameras in the second cabin body.

2. The photographing method according to claim 1, wherein the two tilt cameras in the first cabin perform photographing at 6 angles; the two oblique cameras in the second cabin complete shooting at 6 angles; and finishing shooting at 12 angles at a preset position to obtain a spliced image with three rows and four columns or four rows and three columns.

3. The photographing method according to claim 1, wherein the step S1 includes:

rotating a first rotating shaft of the first cabin to a first inclination angle, and shooting, wherein two cameras of the first cabin obtain images of a first visual angle;

rotating the first rotating shaft to a second inclination angle for shooting, wherein the two cameras of the first cabin body obtain images of a second visual angle;

and rotating the first rotating shaft to a third inclination angle for shooting, wherein the two cameras of the first cabin body obtain an image of a third visual angle.

4. The shooting method of claim 3, wherein the two oblique cameras in the first cabin are symmetrically arranged along a direction perpendicular to the first rotating shaft, and an included angle between the two oblique cameras is as follows: 15 to 30.

5. The photographing method according to claim 4, wherein the step S2 includes:

rotating a second rotating shaft of the second cabin to a fourth inclination angle for shooting, wherein two cameras of the second cabin obtain images of a fourth visual angle;

rotating the second rotating shaft to a fifth inclination angle for shooting, wherein the two cameras of the second cabin body obtain an image of a fifth visual angle;

and rotating the second rotating shaft to a sixth inclination angle for shooting, wherein the two cameras of the second cabin body obtain an image of a sixth visual angle.

6. The shooting method of claim 5, wherein the two oblique cameras in the second cabin are symmetrically arranged along a direction perpendicular to the second rotating shaft, and an included angle between the two oblique cameras is as follows: 60 DEG to 90 deg.

7. The photographing method of claim 5, wherein the first rotation shaft and the second rotation shaft are disposed in parallel with each other.

8. The shooting method according to claim 5, wherein the first angle of view and the fourth angle of view are down-angles of view, the down-angles of view being coincident with a vertical plane; the second angle of view and the fifth angle of view are front-view angles, and the angle between the second inclination angle and the first inclination angle is: 30 ° -45 °, the angle between said fifth inclination and said fourth inclination being: 30 to 45 degrees; the third view angle and the sixth view angle are rear view angles, and an angle between the third inclination angle and the first inclination angle is as follows: 30 ° -45 °, the angle between said sixth inclination and said first inclination being: from 30 DEG to 45 deg.

9. The photographing method according to claim 1, wherein the lenses of the four tilt cameras are fixed focus lenses having a focal length of 20mm to 150 mm.

Images