WO2018133727A1

WO2018133727A1 - Method and apparatus for generating orthophoto map

Info

Publication number: WO2018133727A1
Application number: PCT/CN2018/072318
Authority: WO
Inventors: 薛晓亮; 王涛
Original assignee: 高德软件有限公司
Priority date: 2017-01-20
Filing date: 2018-01-12
Publication date: 2018-07-26
Also published as: CN108335337A; CN108335337B

Abstract

Disclosed in the present application is a method for generating an orthophoto map. The method comprises: selecting, according to a preset sampling rule, sampling trace points from trace points generated by a collection vehicle driving on a road; for a sampling trace point, determining a road area range covered by an orthophoto map to be rendered according to coordinates of the sampling trace point, a driving direction angle of the collection vehicle and an edge length of a drawing area, the range comprising at least one grid, and each grid corresponding to a pixel of the orthophoto map to be rendered; obtaining, according to plane coordinates of each grid, a height value for each grid from point cloud data of the road generated by the collection vehicle while driving, so as to obtain three-dimensional coordinates of the grid; obtaining a color corresponding to each grid according to the three-dimensional coordinates of each grid, picture data of the road and a camera parameter; and rendering the color of the pixel in the orthophoto map to be rendered corresponding to each grid into the color of said corresponding grid. In the solution, height changes of road surfaces are fully taken into consideration, and a more accurate orthophoto map is generated.

Description

Method and device for generating orthophoto image

The present application claims priority to Chinese Patent Application No. JP-A No. No. No. No. No. No. No. No. No. No. No. No. No. .

Technical field

The present application relates to the field of map data processing technologies, and in particular, to a method and apparatus for generating an orthophoto map.

Background technique

The orthophoto map is a plan view with orthographic projection properties. Because of its geometric position information and image intuition, it is used to generate maps to obtain orthophoto maps, which are widely used in navigation products.

When generating an orthophoto map, it is necessary to generate an orthophoto map of the road surface. In the prior art, when generating an orthophoto map of the road surface, the road height is set to a uniform fixed height value during the orthographic projection process. The fixed height value is used as an input parameter of the process, and finally an orthophotograph of the road surface is obtained.

In reality, the road surface often has undulations, and the height of the road surface is not static. Therefore, the prior art does not fully consider the change of the road surface height, and sets the road surface height to a uniform fixed height value, which causes The accuracy of the orthophoto image obtained by the fixed road height value is not high.

Summary of the invention

In view of this, the present application provides a method and apparatus for generating an orthophoto map to eliminate the problem that the orthophoto map generated due to inaccuracy in height values is inaccurate.

In order to achieve the above object, the present application provides a method for generating an orthophoto map, the method comprising:

According to a preset sampling rule, a sampling track point is selected from a track point generated when the collecting vehicle travels on the road;

Determining, according to the coordinates of the sampling track point, the traveling direction angle of the collecting vehicle and the preset side length of the drawing area, the range of the road area covered by the orthophoto image to be rendered, wherein the road area range is included At least one grid, each grid corresponding to one pixel of the orthophoto image to be rendered;

Obtaining plane coordinates of each grid according to the coordinates of the sampling track point and the traveling direction angle of the collecting vehicle;

Obtaining a height value of each grid from the point cloud data of the road generated when the collecting vehicle travels on the road according to the plane coordinates of each grid, and the height value and the plane coordinate of the grid constitute a grid Three-dimensional coordinates

Obtaining a color corresponding to each grid according to three-dimensional coordinates of each grid, picture data of the road, and preset camera parameters, wherein the camera parameter is a camera mounted on the collection vehicle to capture the road image data parameter;

Each grid is rendered in the color of the corresponding pixel in the orthophoto image to be rendered as the color corresponding to the corresponding grid.

The application also provides a device for generating an orthophoto image, the device comprising:

a sampling track point selecting unit, configured to select a sampling track point from a track point generated when the collecting vehicle travels on the road according to a preset sampling rule;

a range determining unit, configured to determine, according to the coordinates of the sampling track point, the traveling direction angle of the collecting vehicle, and the preset side length of the drawing area, the range of the road area covered by the orthophoto image to be rendered, The road area includes a plurality of grids, each grid corresponding to one pixel of the orthophoto image to be rendered;

a plane coordinate determining unit, configured to obtain a plane coordinate of each grid according to coordinates of the sampling track point and a traveling direction angle of the collecting vehicle;

a three-dimensional coordinate determining unit, configured to obtain a height value of each grid from a point cloud data of the road generated when the collecting vehicle travels on the road according to plane coordinates of each grid, and a height value of the grid And the plane coordinates constitute the three-dimensional coordinates of the grid;

a color determining unit, configured to obtain a color corresponding to each grid according to three-dimensional coordinates of each grid, picture data of the road, and preset camera parameters, where the camera parameters are installed on the collecting vehicle The camera parameters of the road picture data;

a rendering unit, configured to render each grid in a color of a corresponding pixel in the orthophoto image to be rendered as a color corresponding to the corresponding grid.

It can be seen from the above technical solution that the present application selects sampling track points from the track points generated when the collecting vehicle is traveling on the road, and for a sampling track point, according to the coordinates of the sampling track points, the traveling direction angle of the collecting vehicle is collected. Determining the range of the road area covered by the orthophoto image to be rendered, the road area range includes a plurality of grids, and calculating the plane coordinates of each grid, according to the plane of each grid Coordinates, obtaining the height value of each grid from the point cloud data of the road generated when the collecting vehicle travels on the road, thereby obtaining the three-dimensional coordinates of the grid, and then according to the three-dimensional coordinates of each grid The picture data of the road and the preset camera parameters are used to obtain the color corresponding to each grid, and the color of each corresponding grid in the orthophoto image to be rendered is rendered as the color corresponding to the corresponding grid. In the above orthophoto image generation process, the point cloud data includes the true height value of the road surface sampling point, so the height value of each grid is obtained from the point cloud data as the most realistic height value of the image corresponding to the grid area. Therefore, generating an orthophoto map based on the three-dimensional coordinates including the true height value sufficiently takes into account the height fluctuation of the road surface, and eliminates the problem that the generated orthophoto map is inaccurate due to inaccuracy of the height value parameter.

DRAWINGS

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings to be used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present application, and other drawings can be obtained according to the drawings without any creative work for those skilled in the art.

1 is a flowchart of a method for generating an orthophoto image according to an embodiment of the present application;

2 is a diagram showing an example of determining a range of road regions covered by an orthophoto image to be rendered according to the present application;

FIG. 3 is a flowchart of a method for determining a target road picture according to another embodiment of the present disclosure;

4 is an exemplary diagram of a camera shooting distance of the present application;

FIG. 5 is a block diagram of a device for generating an orthophoto image according to an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application are clearly and completely described in the following with reference to the drawings in the embodiments of the present application. It is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

The embodiment of the present application provides a method for generating an orthophoto image, and the specific process is shown in FIG. 1 .

Step S100: According to a preset sampling rule, select a sampling track point from a track point generated when the collecting vehicle travels on the road;

Wherein, the collecting vehicle collects the road image data during the driving along the road, and generates a track point in the process, and the position information corresponding to the track point can be obtained by the positioning device carried by the collecting vehicle, such as a GPS positioning device and an inertial navigation device. get.

Preferably, the sampling track point may be selected from the track points generated when the collecting vehicle travels on the road according to the sampling rule that the distance between the adjacent two sampling track points is equal to the preset distance threshold.

Specifically, the preset distance threshold may be equal to the length value in the side length of the preset drawing area, and the side parallel to the traveling direction of the drawing area is a long side, for example, the length value is 20 meters, and the selected adjacent The distance between the two sampling track points is 20 meters.

Step S110: For a sampling track point, determining a road area range covered by the orthophoto image to be rendered according to the coordinates of the sampling track point, the traveling direction angle of the collecting vehicle, and the preset drawing area side length, the road area Included in the range is at least one grid, each grid corresponding to one pixel of the orthophoto image to be rendered;

The coordinate of the sampling track point may be a latitude and longitude coordinate, or may be a plane coordinate after the latitude and longitude conversion; the traveling direction of the collecting vehicle is the traveling direction of the collecting vehicle when the sampling track point is generated, and the driving direction angle refers to the traveling direction and the positive direction. The angle in the north direction can be collected from the vehicle's inertial navigation device; the length of the preset drawing area side length can be determined by the difference between the camera's near shooting distance and the farthest shooting distance value, as shown in Figure 4. For example, the camera's closest shooting distance is 2 meters in front of the camera, the farthest shooting distance is 22 meters in front of the camera, the difference is 20 meters, so the length value can be set to 20 meters; and the width value can be set according to the width of the road. The width of the road covered by the drawing area shall prevail.

Taking the preset drawing area side length as 20m*20m as an example, assuming that the current vehicle is driving in the middle lane, the road area covered by the orthophoto image to be rendered is based on the position of the current sampling track point, and takes 2 meters ahead of the driving direction. To 22 meters, the left side is 10 meters, and the right side is covered by 10 meters. As shown in Figure 2, the adjacent two sampling track points: the distance between the sampling track point 1 and the sampling track point 2 is 20 meters. The roads covered by the two sampling track points corresponding to the drawing area 1 and the drawing area 2 are respectively the sampling track point 1 and the road area range covered by the orthophoto image to be rendered corresponding to the track point 2.

The road area includes at least one grid. Specifically, the number of the grids may be determined according to a preset resolution. For example, the preset resolution is 1000*1000, that is, the resolution of the generated orthophoto map is generated. For 1000*1000, the drawing area contains 1000*1000 grids.

Step 120: Obtain a plane coordinate of each grid according to coordinates of the sampling track point and a traveling direction angle of the collecting vehicle;

Specifically, it can be calculated according to the following grid plane coordinate calculation formula:

X2=x1*cos(yaw)+y1*sin(yaw)+X0;

Y2=-x1*sin(yaw)+y1*cos(yaw)+Y0;

X2 and y2 represent the plane coordinates of the grid, X0 and Y0 represent the coordinates of the sampling trajectory points, x1 and y1 represent the grid coordinates of the grid in the grid coordinate system with the sampling trajectory point as the coordinate origin, and yaw represents the driving direction angle. , the plane coordinates here refers to the coordinates in the Cartesian coordinate system.

Step S130, according to the plane coordinates of each grid, obtain the height value of each grid from the point cloud data of the road generated when the collecting vehicle travels on the road, and the height value and the plane coordinate of the grid constitute The three-dimensional coordinates of the grid;

Among them, the point cloud data is a large number of point data sets, which reflect the three-dimensional coordinates of the sampling points along the road surface of the vehicle. Among them, the three-dimensional coordinates of the sampling points on the road surface can be collected by using the three-dimensional laser radar carried by the collecting vehicle during the driving process of the collecting vehicle.

Preferably, the process of obtaining the height value of each grid from the point cloud data of the road generated when the vehicle is traveling on the road according to the plane coordinates of each grid includes:

For each grid, according to the plane coordinates of the grid, the target point is searched from the point cloud data of the road generated when the collecting vehicle travels on the road, and the distance between the target point and the grid is smaller than the point cloud. The distance between the other points in the data and the grid;

The height value of the target point is determined as the height value of the grid.

In the above process, the distance value of each point in the point cloud data from the grid is calculated, and the minimum distance value is found from the calculated distance value, and the height value in the coordinates of the point corresponding to the minimum distance value is used as the network. The height value of the grid, so that the point in the point cloud closest to each grid position is found by the shortest distance method, and the accuracy of the grid height value is ensured.

Step S140: Obtain a color corresponding to each grid according to three-dimensional coordinates of each grid, picture data of the road, and preset camera parameters, where the camera parameters are installed on the collection vehicle to capture the image data. Camera parameters;

Specifically, first, for a grid, a target road image is determined from image data of the road, and the target road image captures an image of the corresponding area of the grid;

The road picture data collected during the driving process of the collecting vehicle reflects the road surface condition of the road along the driving track in reality, and each picture identifies the position coordinates when the picture is taken.

Among them, the picture data of the road can be directly taken by the camera of the collecting car, such as taking a picture at a shooting speed of 10 shots per second. It is also possible to record the actual road, and then perform picture processing on the recorded video and the trajectory of the collecting vehicle such as the inertial trajectory or the GPS trajectory to obtain picture data with position coordinates. Since the video file is composed of one frame and one frame of image, the picture data with the shooting position can be obtained by performing frame extraction on the video file and matching the INS position or GPS position corresponding to each frame.

Then, determining, according to the three-dimensional coordinates of the grid and the preset camera parameters, the corresponding pixel points of the grid in the target road image;

Specifically, the process of determining the corresponding three-dimensional coordinates of the grid in the target road image involves the conversion of coordinates. Since the three-dimensional coordinates of the grid are three-dimensional coordinates in the world coordinate system, the transformation of the coordinates includes the network. The three-dimensional coordinates of the grid in the world coordinate system are converted into three-dimensional coordinates in the camera coordinate system, and the three-dimensional coordinates in the camera coordinate system are converted into pixel coordinates in the image coordinate system, including:

Assume: P represents the three-dimensional coordinates of the mesh in the world coordinate system, T represents the translation vector = the target origin of the camera - the camera origin, and the rotation matrix R is: R _x (yaw) * R _y (pitch) * R _z (roll) , wherein the direction angle yaw, the pitch angle pitch, and the roll angle roll are rotation angles of the camera coordinate system around the x, y, and z axes;

Converting the coordinate P to the coordinates in the camera coordinate system is: Pc(x _c , y _c , z _c )=R(PT);

The coordinate Pc is converted to a coordinate in the image coordinate system: P ₀ (x ₀ , y ₀ ), where X ₀ = f _x * (x _c / z _c ) + c _x , y _{0 =} f _y * (y _c /z _c )+c _y , where c _x and c _y are offset to the optical axis, and f _x and f _y are physical focal lengths. The optical axis offset, the physical focal length, and the rotation angle of the camera coordinate system around the x, y, and z axes belong to preset camera parameters.

Finally, the color of the pixel is taken as the color corresponding to the grid.

Step S150: Render, according to each grid, a color of a corresponding pixel in the orthophoto image to be rendered as a color corresponding to the corresponding grid;

Wherein, the grid points are colored according to the color corresponding to the grid, and the orthophoto image is obtained after the road coverage is completed.

In the technical solution of the embodiment, the sampling track point is selected from the track points generated when the collecting vehicle is traveling on the road, and the sampling direction point is based on the coordinates of the sampling track point, the driving direction angle of the collecting vehicle, and the preset. The length of the drawing area is determined, and the range of the road area covered by the orthophoto image to be rendered is determined. The road area includes a plurality of grids, and the plane coordinates of each grid are calculated, according to the plane coordinates of each grid. Obtaining a height value of each grid in the point cloud data of the road generated when the collecting vehicle travels on the road, thereby obtaining three-dimensional coordinates of the grid, and further, according to the three-dimensional coordinates of each grid, the road The image data and the preset camera parameters obtain the color corresponding to each grid, and render the color of the corresponding pixel in each of the grids in the orthophoto image to be rendered as the color corresponding to the corresponding grid. In the above orthophoto image generation process, the point cloud data includes the true height value of the road surface sampling point, so the height value of each grid in the point cloud data is the true height value of the image corresponding to the grid area, so based on the The three-dimensional coordinates including the true height value to generate the orthophoto image fully take into account the height fluctuation of the road surface, and eliminate the problem that the generated orthophoto image is inaccurate due to the inaccuracy of the height value parameter.

In an embodiment of the present application, for a grid, a process of determining a target road image from the image data of the road, and the process of capturing the image of the corresponding area of the mesh by the target road image, as shown in FIG. 3, specifically includes:

Step S300: Calculate, according to a grid, a distance value between a shooting position of each picture in the road picture data and a plane coordinate of the grid;

Specifically, as shown in FIG. 4, the camera can only capture the road surface between the closest shooting distance of 2 meters and the farthest shooting distance of 22 meters, so the distance value from the shooting position of the picture to the plane coordinate of the grid Determine the target road image.

Take the coordinates of the shooting position as the converted plane coordinates as an example: the shooting position coordinates are (x1, y1), the plane coordinate of a grid is (X1, Y1), and the distance between the shooting position coordinates and the grid plane coordinates is calculated. value:

Step S310, taking a road picture whose distance value is between the closest shooting distance value and the farthest shooting distance value of the camera as a target road picture for capturing the image of the corresponding area of the mesh;

Specifically, the calculated distance value may have one or more between the closest shooting distance of 2 meters and the farthest shooting distance of 22 meters, that is, the distance value is located between the camera's closest shooting distance value and the farthest shooting distance value. If the road picture is one or more, then

If the road value between the recent shooting distance value and the farthest shooting distance value of the camera is one, the road image is taken as the target road image of the image corresponding to the grid corresponding region;

If the distance value is one or more road pictures between the closest shooting distance value and the farthest shooting distance value of the camera, calculate a distance value corresponding to the road picture and a closest shooting distance of the camera for each road picture. An absolute value of the difference of values, the distance value corresponding to the road picture is a distance value of a shooting position of the picture to a plane coordinate of the grid;

A road picture with the smallest absolute value is selected as the target road picture for capturing the image of the corresponding area of the grid.

In the above embodiment, when there are a plurality of road pictures whose distance values are between the closest shooting distance value and the farthest shooting distance value of the camera, when the shooting position of the road picture is closest to the grid position, the image of the grid area is captured. A picture of the road is used as the basis for coloring. This is because the closer the image is taken, the clearer the picture of the object is, and the color obtained is the most realistic. Then the image of the road image is selected when the shooting position of the road picture is closest to the grid position. A road image is used as a coloring basis to make the color of the grid point closest to the actual color of the image point, so that the generated orthophoto image is more accurate.

The embodiment of the present application further provides an orthophoto image generating device. As shown in FIG. 5, the device includes:

The sampling track point selecting unit 500 is configured to select a sampling track point from the track points generated when the collecting vehicle travels on the road according to a preset sampling rule;

The range determining unit 510 is configured to determine, according to the coordinates of the sampling track point, the traveling direction angle of the collecting vehicle, and the preset side length of the drawing area, the range of the road area covered by the orthophoto image to be rendered, Included in the road area range is at least one grid, each grid corresponding to one pixel point of the orthophoto image to be rendered;

a plane coordinate determining unit 520, configured to obtain plane coordinates of each grid according to coordinates of the sampling track point and a traveling direction angle of the collecting vehicle;

The three-dimensional coordinate determining unit 530 is configured to obtain, according to the plane coordinate of each grid, a height value of each grid from the point cloud data of the road generated when the collecting vehicle travels on the road, the height of the grid The value and the plane coordinates form the three-dimensional coordinates of the grid;

a color determining unit 540, configured to obtain a color corresponding to each grid according to three-dimensional coordinates of each grid, picture data of the road, and preset camera parameters, where the camera parameters are installed on the collecting vehicle Camera parameters of the road picture data;

The rendering unit 550 is configured to render the color of each corresponding grid in the orthographic image to be rendered as the color corresponding to the corresponding grid.

Preferably, the sampling track point selecting unit 500 selects a process of sampling the track points from the track points generated when the collecting vehicle travels on the road according to a preset sampling rule, and specifically includes:

According to the sampling rule that the distance between two adjacent sampling track points is equal to the preset distance threshold, the sampling track points are selected from the track points generated when the collecting vehicle travels on the road.

Preferably, the three-dimensional coordinate determination 530 unit obtains a height value of each grid from point cloud data of the road generated when the collecting vehicle travels on the road according to plane coordinates of each grid, Specifically include:

Preferably, the color determining unit 540 obtains a color corresponding to each grid according to the three-dimensional coordinates of each of the grids, the image data of the road, and the preset camera parameters, and specifically includes:

Determining, from a picture data of the road, a target road picture for a grid, where the target road picture captures an image of the corresponding area of the grid;

Determining, according to the three-dimensional coordinates of the grid and the preset camera parameters, a corresponding pixel of the grid in the target road image; and using the color of the pixel as the color corresponding to the grid.

Preferably, the color determining unit 540 determines a target road image from the picture data of the road for a grid, and the process of capturing the image of the corresponding area image of the target road image includes:

Calculating, for a grid, a distance value of a shooting position of each picture in the road picture data to a plane coordinate of the grid;

A road picture having a distance value between the closest shooting distance value and the farthest shooting distance value of the camera is taken as a target road picture for capturing the image of the corresponding area of the mesh.

Preferably, the determining unit 540, as a process of capturing a road image between the closest shooting distance value and the farthest shooting distance value of the camera as the target road image of the corresponding image of the grid corresponding region, specifically includes:

If the distance value is one or more road pictures between the closest shooting distance value and the farthest shooting distance value of the camera, calculate a distance value corresponding to the road picture and a closest shooting distance of the camera for each road picture. An absolute value of the difference of values, the distance value corresponding to the road picture is a distance value of a shooting position of the road picture to a plane coordinate of the grid;

Finally, it should also be noted that in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities. There is any such actual relationship or order between operations. Furthermore, the term "comprises" or "comprises" or "comprises" or any other variations thereof is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device that comprises a plurality of elements includes not only those elements but also Other elements, or elements that are inherent to such a process, method, item, or device. An element that is defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device that comprises the element.

The various embodiments in the present specification are described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same similar parts between the various embodiments may be referred to each other.

The above description of the disclosed embodiments enables those skilled in the art to make or use the application. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the application is not limited to the embodiments shown herein, but is to be accorded the broadest scope of the principles and novel features disclosed herein.

Claims

A method for generating an orthophoto map, the method comprising:

According to a preset sampling rule, a sampling track point is selected from a track point generated when the collecting vehicle travels on the road;

Determining, according to the coordinates of the sampling track point, the traveling direction angle of the collecting vehicle and the preset side length of the drawing area, the range of the road area covered by the orthophoto image to be rendered, wherein the road area range is included At least one grid, each grid corresponding to one pixel of the orthophoto image to be rendered;

Obtaining plane coordinates of each grid according to the coordinates of the sampling track point and the traveling direction angle of the collecting vehicle;

Obtaining a height value of each grid from the point cloud data of the road generated when the collecting vehicle travels on the road according to the plane coordinates of each grid, and the height value and the plane coordinate of the grid constitute a grid Three-dimensional coordinates

Obtaining a color corresponding to each grid according to three-dimensional coordinates of each grid, picture data of the road, and preset camera parameters, wherein the camera parameter is a camera mounted on the collection vehicle to capture the road image data parameter;

Each grid is rendered in the color of the corresponding pixel in the orthophoto image to be rendered as the color corresponding to the corresponding grid.
The method according to claim 1, wherein the selecting the sampling track points from the track points generated when the collecting vehicle travels on the road according to the preset sampling rule comprises:

According to the sampling rule that the distance between two adjacent sampling track points is equal to the preset distance threshold, the sampling track points are selected from the track points generated when the collecting vehicle travels on the road.
The method according to claim 1, wherein, according to the plane coordinates of each grid, the height values of each grid are obtained from the point cloud data of the road generated when the vehicle is traveling on the road, including:

For each grid, according to the plane coordinates of the grid, the target point is searched from the point cloud data of the road generated when the collecting vehicle travels on the road, and the distance between the target point and the grid is smaller than the point cloud data. The distance between the other points and the grid;

The height value of the target point is determined as the height value of the grid.
The method according to claim 1, wherein the obtaining a color corresponding to each grid according to the three-dimensional coordinates of each grid, the picture data of the road, and the preset camera parameters comprises:

Determining, from a picture data of the road, a target road picture for a grid, where the target road picture captures an image of the corresponding area of the grid;

Determining, according to the three-dimensional coordinates of the grid and the preset camera parameters, a corresponding pixel point of the grid in the target road image;

The color of the pixel is used as the color corresponding to the grid.
The method according to claim 4, wherein the target road image is determined from the picture data of the road for a grid, and the target road image captures the corresponding area image of the grid, including:

Calculating a distance value of a shooting position of each road picture in the road picture data to a plane coordinate of the grid for one grid;

A road picture having a distance value between the closest shooting distance value and the farthest shooting distance value of the camera is taken as a target road picture for capturing the image of the corresponding area of the mesh.
The method according to claim 5, wherein the road picture having the distance value between the closest shooting distance value and the farthest shooting distance value of the camera is taken as the target road picture for capturing the image of the corresponding area of the mesh ,include:

If the road value between the recent shooting distance value and the farthest shooting distance value of the camera is one, the road image is taken as the target road image of the image corresponding to the grid corresponding region;

If the distance value is one or more road pictures between the closest shooting distance value and the farthest shooting distance value of the camera, calculate a distance value corresponding to the road picture and a closest shooting distance of the camera for each road picture. An absolute value of the difference of values, the distance value corresponding to the road picture is a distance value of a shooting position of the road picture to a plane coordinate of the grid;

A road picture with the smallest absolute value is selected as the target road picture for capturing the image of the corresponding area of the grid.
An apparatus for generating an orthophoto map, the apparatus comprising:

a sampling track point selecting unit, configured to select a sampling track point from a track point generated when the collecting vehicle travels on the road according to a preset sampling rule;

a range determining unit, configured to determine, according to the coordinates of the sampling track point, the traveling direction angle of the collecting vehicle, and the preset side length of the drawing area, the range of the road area covered by the orthophoto image to be rendered, Included in the road area range is at least one grid, each grid corresponding to one pixel of the orthophoto image to be rendered;

a plane coordinate determining unit, configured to obtain a plane coordinate of each grid according to coordinates of the sampling track point and a traveling direction angle of the collecting vehicle;

a three-dimensional coordinate determining unit, configured to obtain a height value of each grid from a point cloud data of the road generated when the collecting vehicle travels on the road according to plane coordinates of each grid, and a height value of the grid And the plane coordinates constitute the three-dimensional coordinates of the grid;

a color determining unit, configured to obtain a color corresponding to each grid according to three-dimensional coordinates of each grid, picture data of the road, and preset camera parameters, where the camera parameters are installed on the collecting vehicle The camera parameters of the road picture data;

a rendering unit, configured to render each grid in a color of a corresponding pixel in the orthophoto image to be rendered as a color corresponding to the corresponding grid.
The apparatus according to claim 7, wherein the sampling track point selecting unit selects a process of sampling the track points from the track points generated when the collecting vehicle travels on the road according to a preset sampling rule, specifically including :

According to the sampling rule that the distance between two adjacent sampling track points is equal to the preset distance threshold, the sampling track points are selected from the track points generated when the collecting vehicle travels on the road.
The apparatus according to claim 7, wherein said three-dimensional coordinate determining unit obtains, from the point cloud data of said road generated when the vehicle is traveling on said road, based on the plane coordinates of each grid The process of height values of grids, including:

For each grid, according to the plane coordinates of the grid, the target point is searched from the point cloud data of the road generated when the collecting vehicle travels on the road, and the distance between the target point and the grid is smaller than the point cloud. The distance between the other points in the data and the grid;

The height value of the target point is determined as the height value of the grid.
The device according to claim 7, wherein the color determining unit obtains a color corresponding to each grid according to three-dimensional coordinates of each grid, picture data of the road, and preset camera parameters, Specifically include:

Determining, from a picture data of the road, a target road picture for a grid, where the target road picture captures an image of the corresponding area of the grid;

Determining, according to the three-dimensional coordinates of the grid and the preset camera parameters, a corresponding pixel point of the grid in the target road image;

The color of the pixel is used as the color corresponding to the grid.
The apparatus according to claim 10, wherein said color determining unit determines a target road picture from picture data of said road for a grid, said target road picture capturing image of said corresponding area of said grid Process, including:

Calculating a distance value of a shooting position of each picture in the road picture data to a plane coordinate of the grid for one grid;

A road picture having a distance value between the closest shooting distance value and the farthest shooting distance value of the camera is taken as a target road picture for capturing the image of the corresponding area of the mesh.
The device according to claim 11, wherein the color determining unit uses a road image whose distance value is between the closest shooting distance value and the farthest shooting distance value of the camera as the image of the corresponding area of the mesh. The process of targeting road images, including:

If the road value between the recent shooting distance value and the farthest shooting distance value of the camera is one, the road image is taken as the target road image of the image corresponding to the grid corresponding region;

If the distance value is one or more road pictures between the closest shooting distance value and the farthest shooting distance value of the camera, calculate a distance value corresponding to the road picture and a closest shooting distance of the camera for each road picture. An absolute value of the difference of values, the distance value corresponding to the road picture is a distance value of a shooting position of the road picture to a plane coordinate of the grid;

A road picture with the smallest absolute value is selected as the target road picture for capturing the image of the corresponding area of the grid.