CN103167287B - Selective receiving method based on remote sensing image data broadcast and distribution of spatial position - Google Patents

Abstract

The invention discloses a selective receiving method for broadcasting and distributing remote sensing image data based on spatial position, and belongs to the technical fields of geospatial information organization, geographic information system, remote sensing and communication. The method comprises the following steps: 1: setting the GeoSOT grid size used for subdividing the remote sensing image; 2: dividing the image to be transmitted into multiple image blocks with the determined GeoSOT grid; each image block corresponds to A subdivision surface; 3: Use the GeoSOT coding method to encode each subdivision surface to obtain an image code; 4: Combine the image block and its corresponding image code into a data segment, pack it into a broadcast data packet and Carry out broadcast distribution; 5: The receiving end uses the location identifier and the image code to compare bit by bit from high to low. If the corresponding bits of the location identifier and the code are the same, obtain the broadcast data packet, otherwise discard the broadcast data packet. The invention is suitable for selective reception of remote sensing image data in a broadcast communication system.

Description

Selective Reception Method for Remote Sensing Image Data Broadcast Distribution Based on Spatial Position

technical field

The invention relates to the technical fields of geospatial information organization, geographic information system, remote sensing and communication, and in particular to a data selective receiving method for a broadcast communication system.

Background technique

At present, with the continuous enrichment of earth observation methods and the continuous improvement of the ability to obtain spatial information, the spatial data obtained by people is extremely rich, and the abundance of data is accompanied by the rapid development of data services. In the spatial information service mode, the distribution service of remote sensing data is one of the very important contents.

Broadcasting refers to the transmission of data to the receiving end in an area through electromagnetic wave signals. The information is only transmitted in one direction. Only the sending end sends information to the receiving end, and the receiving end does not send any information to the sending end. The information sent by the end is the same. Broadcasting is of great value in data distribution, especially when dealing with multiple receivers requesting the same information, the broadcast communication system shows great advantages, but when the data requirements of the receivers are different, the existing broadcasting system mainly adopts the following There are two ways to achieve personalized data distribution at the receiving end:

Method 1, as shown in Figure 1, introduces a one-step encryption mechanism between the source code and the channel code, and sets different decryption mechanisms for different receivers. Since the decryption mechanism of the receiver is fixed, the receiver can only decrypt the code that matches itself. When the first method is applied to the selective reception of image data, this selective reception method is not flexible enough because it cannot dynamically change the decryption mechanism in real time.

Method 1, as shown in Figure 1, introduces a one-step encryption mechanism between the source code and the channel code, and sets different decryption mechanisms for different receivers. Since the decryption mechanism of the receiver is fixed, the receiver can only decrypt the code that matches itself. Therefore, when method 1 is applied to the selective reception of image data, this selective reception method is not flexible enough because it cannot dynamically change the decryption mechanism in real time.

The second way is to use IP over DVB, that is, assign different IP addresses to different receivers, and the header of the personalized data packet for different receivers has the IP of the receiver, and only the receiver can receive the data packet. The method is also a relatively fixed method that has nothing to do with the spatial location, but in the spatial information service, the receiving end often only needs data related to its geographical location, and the IP over DVB method is difficult to meet the requirements of spatial information selectivity.

From the analysis of the above two methods, it can be seen that neither the encryption mechanism of method 1 nor the IP address of method 2 can realize the dynamic tracking of the geographical location of the receiving end, so a dynamic and flexible selection based on spatial location is designed for the data broadcast distribution system Sexual reception method has important practical significance and high feasibility.

Contents of the invention

In order to solve the above problems, the present invention provides a selective receiving method for broadcasting and distributing remote sensing image data based on spatial position, the purpose of which is to enable the receiving end to receive remote sensing image data within a range related to its geographic location; and to be able to track in real time The geographical location of the receiving end can flexibly receive remote sensing image data.

In order to achieve the above object, the technical solution of the present invention is: a selective receiving method for broadcasting and distributing remote sensing image data based on spatial position, comprising the following steps:

Step 1: Set the GeoSOT grid size used for subdividing remote sensing images;

Step 2: Subdivide the image to be transmitted with the GeoSOT grid determined in step 1 to obtain multiple image blocks; each image block corresponds to a subdivided surface;

Step 3: Utilize the GeoSOT encoding method to encode each subdivision surface obtained in step 2, and obtain the image coding of each subdivision surface corresponding to the image block;

Step 4: Combining the image blocks and image codes corresponding to the subdivided face slices into data segments, using the broadcast data packet packaging method to package the data segments, obtaining broadcast data packets, and broadcasting and distributing the broadcast data packets;

Step 5: The receiving end uses the GeoSOT code of its own spatial position as the location identifier, and compares the location identifier and the image code bit by bit from high to low. If a certain bit of the location identifier and the image code is different, discard the broadcast data packet; If the corresponding bits of the location identifier and the code are the same, the broadcast data packet is obtained.

Further, in step 1, the method for setting the size of the GeoSOT grid used for subdividing the remote sensing image is:

Determine the GeoSOT grid size used for subdivision according to the receiving capability of the receiving end.

Further, the receiving capability of the above-mentioned receiving end is the geographical influence range of the receiving end, the geographical influence range α is determined by the type of the receiving end, and the minimum GeoSOT grid not less than α is found by comparing α with the scale of the 32-level GeoSOT grid.

Further, in Step 5, if the corresponding bits of the position identifier and the code are the same, it can be divided into the following three situations:

1) The location identifier is the same as each corresponding bit of the image code, and the length of the location identifier is less than the length of the image code, then it is known that the broadcast data packet is within the location-related range of the receiving end;

2) The location identifier is the same as each corresponding bit of the image code, and the length of the location identifier is greater than the length of the image code, then it is known that the receiving end is within the broadcast range of the broadcast data packet;

3) The corresponding bits of the location identifier and the image code are the same, and the length of the location identifier is equal to the length of the image code, then it is known that the broadcast data packet is related to the location of the receiving end.

Preferably, the method for determining the location identifier of the receiving end in step five is:

Determine the geographic location of the receiving end, assuming that the GeoSOT grid level determined in step 1 is m, then encode the GeoSOT grid at level m where the geographic location of the receiving end is located, and obtain the location identifier of the receiving end.

Preferably, step two is:

Step 201, calculating the minimum enclosing latitude and longitude rectangle according to the latitude and longitude range of the image to be transmitted;

Step 202, determining the minimum enclosing subdivision rectangle including the minimum enclosing latitude and longitude rectangle; the minimum enclosing subdivision rectangle is the determined GeoSOT grid as a unit;

Step 203, determining the GeoSOT subdivision patch set contained in the minimum outsourcing subdivision rectangle;

Step 204 , for the subdivided surface patch set, calculate the pixel coordinate range of each subdivided surface patch in the image one by one, and obtain the image block corresponding to each subdivided surface patch.

Preferably, the third step is:

Step 301, determine the longitude N and latitude E of the positioning corner point of the subdivided surface patch; make i=1, and the value of m is the level of the GeoSOT grid used; n=N, e=E;

Step 302, judging whether i is less than or equal to m, if yes, then execute step 303, otherwise, execute step 304;

Step 303. Calculate the one-dimensional binary code X _i Y _i of the i-th layer of the subdivision patch:

X _i = n÷2 ^mi (1)

Y _i = e÷2 ^mi (2)

The remainder assignment of formula (1) is n, the remainder assignment of formula (2) is e, make i self-increment by 1, return to step 302;

Step 304 : sequentially combine the one-dimensional binary codes X ₁ Y ₁ ˜X _m Y _m of the subdivision patch at layers 1 to m to obtain the one-dimensional binary code of the subdivision patch.

Beneficial effect:

1. The present invention provides a selective receiving method for broadcasting and distributing remote sensing image data based on spatial position, and selects a suitable GeoSOT subdivision grid for remote sensing images to segment and encode, realizing geographic information and remote sensing image data The combination of , and setting the corresponding location identification on the receiving end, realizes the selective reception of the remote sensing image data within the range related to its geographic location at the receiving end;

2. The selective receiving method designed by this method can dynamically track the geographical location of the receiving end in real time, so as to realize the flexible selective receiving of remote sensing image data according to the geographical range of the receiving end, and realize the high-efficiency transmission of remote sensing image , has important practical significance.

Description of drawings

FIG. 1 is a schematic diagram of an encryption mechanism of an existing broadcast system.

Figure 2 is a schematic diagram of remote sensing image segmentation based on a certain level of GeoSOT grid.

Fig. 3 is the generation process of remote sensing image coding based on GeoSOT coding.

FIG. 4 is a flow chart of selective reception of broadcast data packets by the receiving end.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention more clearly stated, the specific implementation methods of the present invention will be described in detail below in conjunction with specific examples.

The selective receiving method of broadcasting and distributing remote sensing image data based on spatial position of the present invention is based on the GeoSOT subdivision and coding scheme. For this scheme, please refer to the patent application proposed by Peking University: "A Method for Unifying the Existing Longitude and Latitude Subdivision Grid" (The publication number is CN102609525, and the application date is February 10, 2012). This patent application discloses a GeoSOT geographic grid design scheme, which is used to solve the problem of global geographic space subdivision and identification. The scheme adopts full quadtree recursive subdivision, and divides the earth's surface space into 32 levels from the global to the centimeter level. Each GeoSOT subdivision level has its corresponding GeoSOT subdivision grid. The ratio of the areas between the upper and lower levels of the grid is 1/4.

The GeoSOT subdivision system is shown in Table 1, and Table 1 shows the GeoSOT grid size of each subdivision level:

Table 1 GeoSOT grid list

GeoSOT coding is to code the GeoSOT grid, and its one-dimensional binary coding form uses 2-bit binary numbers to code the GeoSOT grid in each GeoSOT level, so the longer the code is, the more GeoSOT level the GeoSOT grid is in. Higher, the finer the GeoSOT grid. It can be seen from this that the GeoSOT code length can imply the GeoSOT level. Since there are 32 levels in the GeoSOT hierarchy, the longest one-dimensional binary code of the GeoSOT code is 64 bits.

GeoSOT coding provides five coding methods, in order to make coding suitable for computer operation, this embodiment selects 64-bit one-dimensional binary coding in GeoSOT coding.

The steps for transmitting and selectively receiving remote sensing images to be transmitted using the GeoSOT grid division and coding scheme are as follows:

Step 1, setting the GeoSOT grid size used for subdividing the remote sensing image; subdividing the remote sensing image with the GeoSOT grid;

The size of the GeoSOT grid used for subdivision should be moderate.

In order to achieve better results and make the image blocks obtained after subdivision fit the geographical influence range of the receiving end, the GeoSOT grid size used for subdivision can be determined according to the receiving capability of the receiving end.

The geographical influence range of the receiving end determines its receiving capability. For example, if the receiving end is a fixed user, a grid of 16 meters (near the equator) will be used; if the receiving end is a vehicle user, a grid of 1 km will be used. The greater the receiving power, the larger the determined GeoSOT grid.

Determine the geographical influence range α based on the type of the receiving end, and compare α with the scale of the 32-level GeoSOT grid to find the level of the smallest GeoSOT grid that is not less than α, which is to divide the remote sensing image for the data package of this level Level m.

Step 2: Divide the image to be transmitted with the m-level GeoSOT grid to obtain multiple image blocks; each image block corresponds to a subdivided surface.

In this embodiment, the specific process of image segmentation is shown in Figure 2, which is divided into the following four steps:

Step 201, calculate the minimum outsourcing latitude and longitude rectangle according to the latitude and longitude range of the image to be transmitted, as shown in the legend (1) box in Figure 2;

Step 202. Determine the minimum enclosing subdivision rectangle including the minimum enclosing latitude-longitude rectangle. The minimum outsourcing subdivision rectangle is the GeoSOT grid of the determined level as the unit, as shown in the legend (2) box in Figure 2;

Step 203, determine the GeoSOT subdivision patch set contained in the minimum outsourcing subdivision rectangle, as shown in the legend (3) box in Figure 2;

Step 204 , for the subdivided surface patch set, calculate the pixel coordinate range of each subdivided surface patch in the image one by one, and obtain the image block corresponding to each subdivided surface patch. The RGB value of each pixel in the image block is the image data to be transmitted.

Step 3: Use the GeoSOT coding method to encode each subdivision patch obtained in step 1, and obtain the image coding of the image block corresponding to each subdivision patch.

The GeoSOT grid encoding scheme is defined based on the latitude and longitude coordinate space, and the latitude and longitude of the positioning corner point (one of the corner points of the subdivided mesh) and the layer calculation encoding can be used. Figure 3 shows the encoding process:

Step 301, determine the longitude N and the latitude E of the positioning corner point of the subdivided surface patch; make i=1, and the value of m is the determined level of the GeoSOT grid; n=N, e=E;

Step 302, judging whether i is less than or equal to m, if yes, then execute step 303, otherwise, execute step 304;

Step 303. Calculate the one-dimensional binary code X _i Y _i of the i-th layer of the subdivision patch:

X _i = n÷2 ^mi (1)

Y _i = e÷2 ^mi (2)

The remainder assignment of formula (1) is n, the remainder assignment of formula (2) is e, make i self-increment by 1, return to step 302;

Step 304 : sequentially combine the one-dimensional binary codes X ₁ Y ₁ ˜X _m Y _m of the subdivision patch at layers 1 to m to obtain the one-dimensional binary code of the subdivision patch.

For example, an image is divided using the m=9-th layer subdivision patch, which adopts the two-dimensional longitude and latitude information in the lower left corner and the subdivision hierarchical calculation code. Assuming that the latitude and longitude of the lower left corner of a subdivision patch is (N39°, E 116°), the calculation process of its one-dimensional binary GeoSOT encoding is as follows:

The first level of latitude: 39÷256＝0 remaining 39

The first level of longitude: 116÷256＝0 remaining 116

Then the one-dimensional binary code of the subdivision patch on the first layer is 00;

The second level of latitude: 39÷128＝0 remaining 39

The second level of longitude: 116÷128＝0 remaining 116

Then the one-dimensional binary code of the subdivision patch on the second layer is 00;

The third level of latitude: 39÷64＝0 remaining 39

The third level of longitude: 116÷64＝1 remaining 52

Then the one-dimensional binary code of the subdivision patch on the third layer is 01;

Latitude level 4: 39÷32＝1 remaining 7

Longitude level 4: 52÷32＝1 remaining 20

Then the one-dimensional binary code of the subdivision patch on the fourth layer is 11;

Latitude level 5: 7÷16＝0 remaining 7

The fifth level of longitude: 20÷16＝1 remaining 4

Then the one-dimensional binary code of the subdivision patch on the fifth layer is 01;

The sixth level of latitude: 7÷8＝0 remaining 7

The 6th level of longitude: 4÷8＝0 remaining 4

Then the one-dimensional binary code of the subdivision patch on the sixth layer is 00;

The 7th level of latitude: 7÷4＝1 remaining 3

The 7th level of longitude: 4÷4＝1 and the remaining 0

Then the one-dimensional binary code of the subdivision patch on the seventh layer is 11;

The 8th level of latitude: 3÷2＝1 remaining 1

The 8th level of longitude: 0÷2＝0 The remaining 0

Then the one-dimensional binary code of the subdivision patch on the 8th layer is 10;

The 9th level of latitude: 1÷1＝1 with a remainder of 0

The 9th level of longitude: 0÷1＝0 remaining 0

Then the one-dimensional binary code of the subdivision patch on the ninth layer is 10;

Combining the one-dimensional binary codes of the subdivided surface in layers 1-9, the obtained one-dimensional binary code of the subdivided surface is 000001110100111010.

Step 4. Combining the image block corresponding to the subdivided surface and the encoding obtained in step 3 into a data segment, using the broadcast data packet packaging method to pack the data segment to obtain a broadcast data packet, and broadcasting The data packets are broadcast and distributed, and the codes in the broadcast data packets are recorded as video codes.

Step 5, the receiving end uses the GeoSOT code of its own spatial position as the location identifier, compares the location identifier with the image code bit by bit, and discards the broadcast data packet if a certain bit of the location identifier and the image code is different; if the location identifier and If the corresponding bits of the encoding are the same, the broadcast data packet is acquired. FIG. 4 shows the process of selectively receiving broadcast data packets at the receiving end.

Among them, according to the GeoSOT subdivision and coding scheme, the GeoSOT coding is to code the GeoSOT grid, so the longer the code is, the higher the GeoSOT level of the GeoSOT grid is, and the finer the GeoSOT grid is. It can be seen that the GeoSOT code is hierarchical, so the location identifier and the image code are compared bit by bit from high bit to low bit. When comparing bit by bit, the following four situations are obtained:

1) By bit-by-bit comparison, if the location identifier is different from a certain bit of the image code, the broadcast data packet is discarded;

2) By bit-by-bit comparison, the corresponding bits of the location identifier and the image code are the same, and the length of the location identifier is smaller than the length of the image code, indicating that the broadcast data packet is within the location-related range of the receiving end;

3) By bit-by-bit comparison, the corresponding bits of the location identifier and the image code are the same, and the length of the location identifier is greater than the length of the image code, indicating that the receiving end is within the broadcast range of the broadcast data packet;

4) By bit-by-bit comparison, the corresponding bits of the location identifier and the image code are the same, and the length of the location identifier is equal to the length of the image code, indicating that the receiving end is within the broadcast range of the broadcast data packet.

2), 3), and 4) show that the broadcast data packet is related to the location of the receiving end itself, and the acquisition of the broadcast data packet realizes selective reception.

For example, the location identifier of the receiver is: 000001111

The image encoding in the broadcast packet is: 000001110100111010

By bit-by-bit comparison, if the ninth bit of the two is different, the broadcast data packet is not related to the location range of the receiving end, and the receiving end discards the broadcast data packet.

For example, the location identifier of the receiver is: 000001110

The image encoding in the broadcast packet is: 000001110100111010

By bit-by-bit comparison, if the first 9 bits of the two are the same, the broadcast data packet is related to the location of the receiving end itself, and the receiving end receives the broadcast data packet.

For example, the location identifier of the receiver is: 0000011101001110101100

The image encoding in the broadcast packet is: 000001110100111010

By bit-by-bit comparison, if the first 18 bits of the two are the same, the broadcast data packet is related to the location of the receiving end itself, and the receiving end receives the broadcast data packet.

For example, the location identifier of the receiver is: 000001110100111010

The image encoding in the broadcast packet is: 000001110100111010

By bit-by-bit comparison, if the first 18 bits of the two are the same, the broadcast data packet is related to the reception of the broadcast data packet by the receiving end, and the receiving end receives the broadcast data packet.

When the receiving end selectively receives broadcast data packets, in order to achieve better results, the receiving end can realize accurate broadcast data packets with strong geographical influence within its geographical influence range according to its geographical location. Receiving, the GeoSOT level used when encoding the spatial position of the receiving end itself is the GeoSOT level m obtained in step 1;

It can be seen from the above description of the embodiments that the technical solution of the present invention is finally realized through data packet preparation, data distribution and data unpacking in the broadcast communication system. Therefore technical scheme of the present invention can be embodied in the following forms:

①Computer software products developed for the above-mentioned engineering services, including broadcast transmission preprocessing software (data block, GeoSOT segmentation coding), data packet generation and analysis software;

②Protocol for block transmission of image data based on geographic location;

③ Computing equipment formed by deploying or configuring the above software, such as handheld or portable terminal equipment for broadcasting and communication.

It should be pointed out that the above description is only a general implementation of the present invention. In actual application, those skilled in the art can make some adjustments to the technical solution according to the needs, for example: divide and encode the space in other ways, where Under the premise of the principles explained in the present invention, any modifications, equivalent replacements, partial applications, etc., shall be included in the protection scope of the present invention.

Claims (7)

1. The selective receiving method of remote sensing image data broadcast distribution based on spatial position, it is characterized in that, comprises the following steps: Step 1: Set the GeoSOT grid size used for subdividing remote sensing images; Step 2: Subdivide the image to be transmitted with the GeoSOT grid determined in step 1 to obtain multiple image blocks; each image block corresponds to a subdivided surface; Step 3: Utilize the GeoSOT encoding method to encode each subdivision surface obtained in step 2, and obtain the image coding of each subdivision surface corresponding to the image block; Step 4: Combining the image blocks and image codes corresponding to the subdivided face slices into data segments, using the broadcast data packet packaging method to package the data segments, obtaining broadcast data packets, and broadcasting and distributing the broadcast data packets; Step 5: The receiving end uses the GeoSOT code of its own spatial position as the location identifier, and compares the location identifier and the image code bit by bit from high to low. If a certain bit of the location identifier and the image code is different, discard the broadcast data packet; If the corresponding bits of the location identifier and the code are the same, the broadcast data packet is acquired. 2. The selective receiving method of remote sensing image data broadcast distribution based on spatial position as claimed in claim 1, characterized in that, in said step 1, the GeoSOT grid size used for subdividing remote sensing images is set The method is: Determine the GeoSOT grid size used for subdivision according to the receiving capability of the receiving end. 3. The selective receiving method for broadcasting distribution of remote sensing image data based on spatial position as claimed in claim 1, wherein the receiving capability of the receiving end is the geographical influence range of the receiving end, and the geographical influence is determined by the type of the receiving end range α, and compare α with the scale of the 32-level GeoSOT grid to find the smallest GeoSOT grid not smaller than α. 4. The selective receiving method for broadcasting and distributing remote sensing image data based on spatial position as claimed in claim 1, characterized in that, in the step 5, if each corresponding bit of the position identification and coding is the same, it can be divided into the following three Cases: 1) The location identifier is the same as each corresponding bit of the image code, and the length of the location identifier is less than the length of the image code, then it is known that the broadcast data packet is within the location-related range of the receiving end; 2) The location identifier is the same as each corresponding bit of the image code, and the length of the location identifier is greater than the length of the image code, then it is known that the receiving end is within the broadcast range of the broadcast data packet; 3) The corresponding bits of the location identifier and the image code are the same, and the length of the location identifier is equal to the length of the image code, then it is known that the broadcast data packet is related to the location of the receiving end. 5. A selective receiving method for broadcasting and distributing remote sensing image data as claimed in claim 1, characterized in that, the method for determining the position identification of the receiving end in said step 5 is: Determine the geographic location of the receiving end, assuming that the GeoSOT grid level determined in step 1 is m, then encode the GeoSOT grid at level m where the geographic location of the receiving end is located, and obtain the location identifier of the receiving end. 6. A selective receiving method for broadcasting and distributing remote sensing image data as claimed in claim 1, wherein said step 2 is: Step 201, calculating the minimum enclosing latitude and longitude rectangle according to the latitude and longitude range of the image to be transmitted; Step 202, determining the minimum enclosing subdivision rectangle including the minimum enclosing latitude and longitude rectangle; the minimum enclosing subdivision rectangle is the determined GeoSOT grid as a unit; Step 203, determining the GeoSOT subdivision patch set contained in the minimum outsourcing subdivision rectangle; Step 204 , for the subdivided surface patch set, calculate the pixel coordinate range of each subdivided surface patch in the image one by one, and obtain the image block corresponding to each subdivided surface patch. 7. A selective receiving method for broadcasting and distributing remote sensing image data as claimed in claim 1, characterized in that said step 3 is: Step 301, determine the longitude N and latitude E of the positioning corner point of the subdivided surface patch; make i=1, and the value of m is the level of the GeoSOT grid used; n=N, e=E; Step 302, judging whether i is less than or equal to m, if yes, then execute step 303, otherwise, execute step 304; Step 303, calculate the one-dimensional binary code XiYi of the subdivision patch at the i layer: X _i = n÷2 ^mi (1) Y _i = e÷2 ^mi (2) The remainder assignment of formula (1) is n, the remainder assignment of formula (2) is e, make i self-increment by 1, return to step 302; Step 304 : sequentially combine the one-dimensional binary codes X ₁ Y ₁ ˜X _m Y _m of the subdivision patch at layers 1 to m to obtain the one-dimensional binary code of the subdivision patch.