CN105894471A - Fast Correction Method of Small and Medium Scale Orthophotos Based on Large Scale Topographic Maps - Google Patents

Abstract

The invention discloses a method for quickly correcting an orthoimage with a medium and small scale based on a topographic map with a large scale. The method comprises the following steps: A. determining a corresponding scale according to the image resolution; B. extracting the information of buildings and structures in the topographic map with the image scale larger than the image scale; C. finding a building or a structure angular point and recording coordinates of the point; D. correcting the coordinate-free orthographic image by the same point to obtain the result image data. The invention solves the problem of fast correction of the small and medium scale orthoimages of the large scale topographic map; can be used for correcting the orthoimage with the scale of 1:1000 to 1: 10000.

Description

Fast Correction Method of Small and Medium Scale Orthophotos Based on Large Scale Topographic Maps

technical field

The invention relates to the technical field of satellite image processing, in particular to a method for quickly correcting medium and small-scale orthophotos based on large-scale topographic maps.

Background technique

Most of the orthophoto correction methods use the field measurement mode to obtain the real coordinates of the feature points. This method is inefficient, and the cost and cycle are very high. For production units that already have a certain amount of data accumulation, data mining methods can be used to obtain the required feature point information and correct the images to achieve the purpose of reducing field surveying and mapping.

Most urban surveys are based on large-scale topographic maps, generally 1:500 and 1:2000 scales. Therefore, data mining can be performed on topographic maps to obtain the required image control point information. According to the relevant surveying and mapping regulations, the tolerance of different scale topographic maps should not exceed 0.2 millimeters on the map, and the tolerance of 1:500 scale surface objects should not exceed 0.1 meters according to the scale calculation, while the 1:1000 scale topographic map should not exceed the root point of the map. The accuracy requirements of the map should not exceed 0.1 mm, that is, 0.1 m on the ground, so the 1:500 topographic map can meet the needs of 1:1000 topographic map root control. Based on this principle, when the scale of a large-scale topographic map is 1:Scall, its corresponding ground object points can meet the requirements of root control of 1:2*Scall and smaller scale topographic maps. Therefore, the feature points of the larger-scale topographic map can meet the needs of the smaller-scale orthophoto image control points (similar to map root control).

Based on this principle, it is generally believed that the feature points of 1:500 topographic map can meet the accuracy requirements of 1:1000 and smaller scale orthophoto images for map root points; The accuracy requirements of orthophotos for map root points; 1:2000 topographic map feature points can meet the accuracy requirements of 1:5000 and smaller scale orthophotos for map root points; 1:5000 topographic map feature points can meet 1:10000 and The accuracy requirements of the map root points for smaller-scale orthophotos can be deduced by analogy for others.

Contents of the invention

The technical problem solved by the present invention is to provide a fast correction method for medium and small-scale orthophoto images based on large-scale topographic maps, through data mining, the required image control point information is extracted, and efficient image correction is realized.

The technical scheme that the present invention solves the problems of the technologies described above is:

Described method comprises the following steps:

A. Determine the corresponding scale according to the image resolution;

B. Extract the information of buildings and structures in topographic maps larger than the image scale;

C. Find the corner point of the building or structure, and record the coordinates of the point;

D. Correct the coordinate-free orthophoto with the same point to obtain the resulting image data.

Further, a more specific solution could be:

Described step A comprises the following steps:

A1. The image resolution is D meters, and the corresponding scale is 1:10000D;

A2. If it is not the national standard scale, convert it to the national standard scale.

Described step A2 comprises the following steps:

A21. If the scale is greater than 1:1000 and less than 1:500, use the scale of 1:1000;

A22. If the scale is greater than 1:2000 but less than 1:1000, use the scale of 1:2000;

A23. If the scale is greater than 1:2000 and less than 1:5000, use the scale of 1:5000;

A24. If the scale is greater than 1:5000 and less than 1:10000, use the scale of 1:10000.

Described step B comprises the following steps:

B1. Select a topographic map larger than the scale as a coordinate reference;

B2. Delete features other than buildings and structures;

B3. Unlock the locked layer and delete the information of simple houses and structures such as sheds;

B4. Clean up the layer and recalculate the graphics range.

Described step C comprises the following steps:

C1, open the topographic map and image map of step B;

C2. According to the principle of uniform distribution, find the same feature points in the common part of the image map and topographic map;

C3. Record the image coordinates of the same feature point and the corresponding coordinates of the topographic map.

Said step D comprises the following steps:

D1. Perform adjustment calculation for points with the same name;

D2. If the adjustment accuracy requirements are met, enter the image correction link;

D3. If the accuracy requirement is not met, remove the point, find a new feature point near the point, and return to step C;

D4. Correct the image to obtain corrected image data;

D5. According to the requirements, output the result data by framing or in the specified format.

Based on the large-scale topographic map, the present invention extracts the required image control point information through data mining, and realizes efficient image correction; the whole implementation method has the advantages of easy implementation, simple principle, and low cost, greatly reducing the impact of image correction. The demand for image control points in the wild. The correction method of the present invention can be used for correcting orthophoto images with a scale of 1:1000 to 1:10000.

Description of drawings

Below in conjunction with accompanying drawing, the present invention is further described:

Fig. 1 is a schematic flow chart of the method of the present invention.

detailed description

As shown in Figure 1, it is a flow chart of the method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps of the present invention; the following is based on 1:500 scale topographic maps to correct 1:5000 orthophotos, and the operating platform is PC. Windows 10 operating system; The present invention is described in detail.

Method of the present invention comprises the following steps:

A. Determine the corresponding scale according to the image resolution;

B. Extract the information of buildings and structures in topographic maps larger than the image scale;

C. Find the corner point of the building or structure, and record the coordinates of the point;

D. Correct the coordinate-free orthophoto with the same point to obtain the resulting image data.

More specifically, the specific steps of Step A are as follows:

A1. The image resolution is 0.46 meters, and the corresponding scale is 1:4600;

A2. If it is not the national standard scale, convert it to the national standard scale. According to the above reasoning, if the scale is greater than 1:2000 and less than 1:5000, use the 1:5000 scale;

The specific steps of step B are as follows:

B1. Using the 1:500 topographic map as a reference record, lock the layer where the buildings and structures are located;

B2. Delete features other than buildings and structures;

B3. Unlock the locked layer, delete the information of simple houses and structures such as sheds;

B4. Clean up the layer and recalculate the graphics range.

The specific steps of step C are as follows:

C1. Open the topographic map and the image map to be corrected in step B through GlobalMapper14 software (a map drawing software), and set the coordinate projection information;

C2. According to the principle of uniform distribution, such as 5*5 mode, find the same ground object points in the common part of the image map and the topographic map;

C3. Record the image coordinates of the same feature point and the corresponding coordinates of the topographic map.

The specific steps of step D are as follows:

D1. Use the GlobalMapper14 software to perform adjustment calculations for the points with the same name;

D2. If the adjustment accuracy requirements are met, enter the image correction link;

D3. If the accuracy requirement is not met, remove the point, find a new feature point near the point, and return to step C2;

D4. Correct the image through the GlobalMapper14 software to obtain the corrected image data;

D5. According to the requirements, output the result data by framing or in the specified format.

Claims (10)

1. A kind of medium and small-scale orthophoto fast correction method based on large-scale topographic map, it is characterized in that, described method comprises the following steps: A. Determine the corresponding scale according to the image resolution; B. Extract the information of buildings and structures in topographic maps larger than the image scale; C. Find the corner point of the building or structure, and record the coordinates of the point; D. Correct the coordinate-free orthophoto with the same point to obtain the resulting image data. 2. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 1, wherein said step A comprises the following steps: A1. The image resolution is D meters, and the corresponding scale is 1:10000D; A2. If it is not the national standard scale, convert it to the national standard scale. 3. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 2, wherein said step A2 comprises the following steps: A21. If the scale is greater than 1:1000 and less than 1:500, use the scale of 1:1000; A22. If the scale is greater than 1:2000 but less than 1:1000, use the scale of 1:2000; A23. If the scale is greater than 1:2000 and less than 1:5000, use the scale of 1:5000; A24. If the scale is greater than 1:5000 and less than 1:10000, use the scale of 1:10000. 4. The method for quickly correcting small and medium-scale orthophoto images based on large-scale topographic maps according to claim 1, 2 or 3, wherein said step B comprises the following steps: B1. Select a topographic map larger than the scale as a coordinate reference; B2. Delete features other than buildings and structures; B3. Unlock the locked layer and delete the information of simple houses and structures such as sheds; B4. Clean up the layer and recalculate the graphics range. 5. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 1, 2 or 3, wherein said step C comprises the following steps: C1, open the topographic map and image map of step B; C2. According to the principle of uniform distribution, find the same feature points in the common part of the image map and topographic map; C3. Record the image coordinates of the same feature point and the corresponding coordinates of the topographic map. 6. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 4, wherein said step C comprises the following steps: C1, open the topographic map and image map of step B; C2. According to the principle of uniform distribution, find the same feature points in the common part of the image map and topographic map; C3. Record the image coordinates of the same feature point and the corresponding coordinates of the topographic map. 7. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 1, 2 or 3, wherein said step D comprises the following steps: D1. Perform adjustment calculation for points with the same name; D2. If the adjustment accuracy requirements are met, enter the image correction link; D3. If the accuracy requirement is not met, remove the point, find a new feature point near the point, and return to step C; D4. Correct the image to obtain corrected image data; D5. According to the requirements, output the result data by framing or in the specified format. 8. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 4, wherein said step D comprises the following steps: D1. Perform adjustment calculation for points with the same name; D2. If the adjustment accuracy requirements are met, enter the image correction link; D3. If the accuracy requirement is not met, remove the point, find a new feature point near the point, and return to step C; D4. Correct the image to obtain corrected image data; D5. According to the requirements, output the result data by framing or in the specified format. 9. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 5, wherein said step D comprises the following steps: D1. Perform adjustment calculation for points with the same name; D2. If the adjustment accuracy requirements are met, enter the image correction link; D3. If the accuracy requirement is not met, remove the point, find a new feature point near the point, and return to step C; D4. Correct the image to obtain corrected image data; D5. According to the requirements, output the result data by framing or in the specified format. 10. The method for quickly correcting small and medium-scale orthophotos based on large-scale topographic maps according to claim 6, wherein said step D comprises the following steps: D1. Perform adjustment calculation for points with the same name; D2. If the adjustment accuracy requirements are met, enter the image correction link; D3. If the accuracy requirement is not met, remove the point, find a new feature point near the point, and return to step C; D4. Correct the image to obtain corrected image data; D5. According to the requirements, output the result data by framing or in the specified format.