A method for scene cataloging of monowire array camera on-orbit stereo imaging data

Abstract

The application provides a method for scene cataloging of single linear array camera on-orbit stereo imaging data, which comprises the following steps: segmenting the strip data of single linear array camera on-orbit stereo imaging by searching time code jump to obtain each single imaging data segment; on the basis of a current satellite earth grid system model constructed in advance, cataloging each data scene based on actual imaging geographical position to obtain the scene number of each data segment, Path / Row number information of each scene and other metadata information; scenes with the same Row number are the same imaging position scenes; and the scene cataloging information results of each data segment are sequentially merged according to the Row number increasing order to obtain a merged scene cataloging information file. The application processes multi-view imaging data in an imaging strip by scene, and merges multi-view information, which is convenient for subsequent stereo product processing and also facilitates user to obtain multi-view metadata information of a scene during query.

Description

Technical Field

[0001] This invention relates to a scene-by-scene cataloging method for stereo imaging data from a single-line array camera on the same track, belonging to the field of remote sensing data preprocessing. Background Technology

[0002] To generate stereo imaging data, remote sensing satellites typically employ dual-line or triple-line arrays. This involves using line-scan cameras mounted at different angles along the flight path to image the same ground feature from different perspectives, thus obtaining stereo image pairs. Examples include the triple-line array camera on the ZY-3 satellite and the dual-line array camera on the Gaofen-7 satellite.

[0003] In recent years, with the improvement of satellite agility technology, by rapidly maneuvering satellites, single-line array cameras can perform push-broom imaging of the same strip area at different imaging angles in the same orbit, obtaining stereo image pairs. Examples include the Gaofen-Multi-Mode satellite and the Gaofen-1 satellite.

[0004] Unlike single-line array camera data in multi-line array stereo imaging, single-line array co-track stereo imaging data is not continuous push-broom strip imaging data, but rather multiple repeated push-brooms of a short strip. If scene segmentation is performed using the existing continuous push-broom strip data method, the following problems will occur: First, the attitude angle data in the auxiliary data will jump during view switching, leading to incorrect interpolation of the attitude of nearby points, thus causing errors in imaging positioning calculations; Second, because it is multiple imaging of the same strip, scene segmentation based on the Earth Grid System (WRS) will result in repeated row numbers instead of monotonically increasing, making existing scene segmentation methods unsuitable; In addition, the multi-view stereo imaging of the same scene area is divided into multiple scenes, which can only be linked together through latitude and longitude information, making it difficult to obtain the level 0 data of multiple views in subsequent stereo product processing, and making it inconvenient for users to obtain multi-view information of stereo scenes. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a scene-by-scene cataloging method for stereoscopic imaging data of a single line array camera on the same track. This method can process multi-view imaging data in an imaging strip into scenes and merge the multi-view information, so that multi-view level 0 data of one scene can be obtained simultaneously during subsequent stereoscopic product processing, and multi-view metadata information of one scene can be obtained simultaneously when the user queries.

[0006] The technical solution of the present invention is as follows: Firstly, a method for scene-by-scene cataloging of stereoscopic imaging data from a single-line array camera on the same track is provided, comprising:

[0007] The strip data of the same-track stereo imaging of a single-line array camera is segmented by searching for time code jumps to obtain each single imaging data segment, and each segment of data corresponds to the one-view observation data of the strip area.

[0008] Construct a model of the current satellite Earth grid system, and catalog each segment of data based on the actual imaging geographical location to obtain the number of segments of each data segment, the nadir point trajectory number and the latitude direction number along the trajectory of each segment, and other metadata information; where the nadir point trajectory number is denoted as Path number, and the latitude direction number along the trajectory is denoted as Row number;

[0009] Scenes with the same Row number are considered to be scenes at the same imaging location. The scene cataloging information results of each data segment are merged in ascending order of Row number, and the scene element information with the same Row number is merged to obtain a merged scene cataloging information file.

[0010] Preferably, the strip data of the single-line array camera's co-track stereo imaging consists of multiple push-broom images of the single-line array camera at a certain longitude position.

[0011] Preferably, the strip data of stereo imaging on the same track by a single line array camera is segmented by searching for time code transitions to obtain each single imaging data segment, specifically:

[0012] a. Set the first line of the striped data to be the start line of the first segment;

[0013] b. Starting from the second line, parse the time code in the data line by line. If the time code of the current line minus the time code of the previous line is greater than the jump threshold, then set the previous line number as the end line of the previous segment, and set the current line number as the start line of the new segment.

[0014] c. Repeat step b until the strip data ends, and set the last line to the end of the last segment;

[0015] The start and end line numbers of each segment are used as segment index information. Based on the start and end line numbers of each segment in the segment index information, the data of each segment is obtained from the strip. Each segment data is the one-view observation data of the corresponding strip area.

[0016] Preferably, the Earth grid system is constructed based on the satellite's orbital parameters and camera swath width. The grid parameters of the Earth grid system include Path number and Row number.

[0017] The Path number corresponds to the number of nadir points within one orbital return cycle of the satellite, which is equal to the orbital return cycle multiplied by the number of orbits per day; the Row number is equal to the Earth's north-south circumference divided by the image width.

[0018] Preferably, when merging metadata information from different scenes, the fields that need to be merged include:

[0019] The start and end line information are merged to obtain the positioning information of each view imaging data of a scene in a strip;

[0020] The imaging time information of the data is merged to obtain the imaging time of each view data;

[0021] The satellite attitude and angle information during the shooting is merged to obtain the satellite attitude and angle information for each view.

[0022] The integration time information is merged to obtain the scene center line integration time information of each view image;

[0023] The Level 0 data file name is the agreed-upon Level 0 data file name when the physical scene segmentation mode is used. The Level 0 data of a scene will be extracted from the strip based on the start and end line information of the scene in the catalog file.

[0024] Preferably, in the merged catalog information file, the metadata information for each scene includes multi-view imaging information.

[0025] In a second aspect, the present invention provides a scene-by-scene cataloging system for stereoscopic imaging data of a single-line array camera on the same track, characterized in that it includes:

[0026] Imaging data segmentation module: The strip data of the same track stereo imaging of the single line array camera is segmented by searching for time code jumps to obtain each single imaging data segment;

[0027] Scene-by-scene cataloging module: Based on the pre-constructed current satellite Earth grid system model, each data segment is cataloged according to the actual imaging geographical location, resulting in the number of scenes for each data segment, the nadir point trajectory number and the Path / Row number along the trajectory, and other metadata information; where the nadir point trajectory number is denoted as Path number, and the latitudinal number along the trajectory is denoted as Row number;

[0028] Scene data merging module: Merges the scene cataloging information results of each data segment in ascending order of Row number, and merges the scene data information with the same Row number to obtain a merged cataloging information file.

[0029] Preferably, the imaging data segmentation module segments the strip data of the single-line array camera's co-track stereo imaging by searching for time code transitions to obtain each single imaging data segment. The specific process is as follows:

[0030] a. Set the first line of the striped data to be the start line of the first segment;

[0031] b. Starting from the second line, parse the time code in the data line by line. If the time code of the current line minus the time code of the previous line is greater than the jump threshold, then set the previous line number as the end line of the previous segment, and set the current line number as the start line of the new segment.

[0032] c. Repeat step b until the strip data ends, and set the last line to the end of the last segment;

[0033] The start and end line numbers of each segment are used as segment index information. Based on the start and end line numbers of each segment in the segment index information, the data of each segment is obtained from the strip. Each segment data is the one-view observation data of the corresponding strip area.

[0034] Preferably, when the scene data merging module merges the scene data information, the fields that need to be merged include:

[0035] The start and end line information are merged to obtain the positioning information of each view imaging data of a scene in a strip;

[0036] The imaging time information of the data is merged to obtain the imaging time of each view data;

[0037] The satellite attitude and angle information during the shooting is merged to obtain the satellite attitude and angle information for each view.

[0038] The integration time information is merged to obtain the scene center line integration time information of each view image;

[0039] The Level 0 data file name is the agreed-upon Level 0 data file name when the physical scene segmentation mode is used. The Level 0 data of a scene will be extracted from the strip based on the start and end line information of the scene in the catalog file.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] (1) This invention merges the cataloging results of the segmented multiview data so that the metadata information of each scene contains the information of each (multiview) imaging, instead of being divided into multiple scenes, which facilitates the production and processing of subsequent stereoscopic products, as well as the query and further processing of multiview data by users.

[0042] (2) This invention realizes the scene-by-scene cataloging of single-strip 2-view or 3-view stereoscopic imaging data. After subsequent stereoscopic product processing and user verification, the cataloging results are reasonable and easy to use. Detailed Implementation

[0043] A method for scene-by-scene cataloging of stereo imaging data from a single-line array camera on the same track includes the following steps:

[0044] (1) The stereo imaging data of the single-line array camera is segmented to obtain each single imaging data segment;

[0045] Segmenting the data of a single-line array camera's co-track stereo imaging means separating the data from multiple imaging sessions of the same area. Two-view stereo is divided into two segments, and three-view stereo is divided into three segments. Each segment is a continuous push-broom imaging data.

[0046] When repeatedly pushing-broom imaging the same area using a different view, a satellite maneuver occurs, changing its attitude angle to image the same strip area. This maneuver typically takes more than 10 seconds, while the time of a single push-broom imaging data increments by second. Therefore, the time code jump in the data can be used to capture the imaging transitions, enabling segmentation of the multi-view stereo imaging data. Based on the segment index information, each segment is obtained from the strip data. Since each segment conforms to the characteristics of continuous push-broom imaging, it can be cataloged by scene using the existing single-view strip data method.

[0047] (2) Catalog each segment of data separately.

[0048] Scene-by-scene cataloging of each data segment is based on the pre-constructed current Satellite Earth Grid System (WRS) model (grid points are identified by Path / Row numbers). Based on the actual imaging geographic location, a segment of data is cataloged to obtain the number of scenes in a segment of data, the Path / Row number information of each scene, and other metadata information.

[0049] By cataloging a segment of data according to the actual imaging geographic location and the Earth grid system, it can be ensured that the same row number indicates the same imaging location in the multi-view imaging data, and the segmentation of multi-view imaging data has good consistency.

[0050] (3) Merge the scene-specific cataloging information of each data segment by scene.

[0051] The cataloging information of each data segment is arranged in ascending order of Row number. Scene data with the same Row number are then merged to obtain a single merged cataloging information file. This file contains metadata for each scene, including information from each (multi-view) imaging session. Subsequent product manufacturing processes use this cataloging information file to retrieve Level 0 data, simultaneously obtaining multi-view data for a single scene, thus enabling the production of stereoscopic products. After the data is archived using this cataloging information file, users will also receive the multi-view metadata information for each scene when querying its data.

[0052] Specifically, a method for scene-by-scene cataloging of stereo imaging data from a single-line array camera on the same track includes the following steps:

[0053] (1) The stereo imaging data of the single-line array camera on the same track is segmented to obtain the single imaging data segments.

[0054] Segmenting the data of a single-line array camera's co-track stereo imaging means separating the data from multiple imaging sessions of the same area. Two-view stereo is divided into two segments, and three-view stereo is divided into three segments. Each segment is a continuous push-broom imaging data.

[0055] When repeatedly performing pushbroom imaging on the same area, satellites typically require a time maneuver of more than 10 seconds to change their attitude angle and image the same area. The impact of this maneuver on the data can be used for segmentation in two ways: one is to capture changes in attitude angle, primarily a significant change in pitch angle; the other is to capture a timecode jump of more than 10 seconds in the data caused by the maneuver. Of these two methods, setting the threshold for the pitch angle change during the maneuver is difficult; using the timecode jump logic is simpler. The threshold for the timecode jump can be set based on the satellite's agility capabilities, and in the future, it may be less than 10 seconds. The specific steps for data segmentation are as follows:

[0056] a) Set the first line of the strip to be the first line of the first paragraph;

[0057] b) Starting from the beginning row, parse the time code in the auxiliary data line by line. If the time code of the current row minus the time code of the previous row is greater than the jump threshold, then set the previous row number as the end row of the previous segment, and set the current row number as the beginning row of the new segment.

[0058] c) Repeat step b) until the strip data ends, and set the last line to the end of the last segment;

[0059] d) The start and end line numbers of each of the above segments serve as segment index information;

[0060] e) Based on the start and end row numbers of each segment in the segment index information, the data of each segment can be obtained from the strip. Each segment of data corresponds to one (1-look) observation data of the strip area, which is consistent with the characteristics of continuous push-broom imaging.

[0061] The data segmentation described above is logical segmentation, which obtains the index information of the segments, and does not require physical segmentation of the data.

[0062] (2) Catalog each segment of data separately.

[0063] Scene-by-scene cataloging of each data segment is based on the pre-constructed current Satellite Earth Grid System (WRS) model (grid points are identified by Path / Row numbers). Based on the actual imaging geographic location, a segment of data is cataloged to obtain the number of scenes in a segment of data, the Path / Row number information of each scene, and other metadata information.

[0064] The Earth Grid System (WRS) is a grid-based positioning system distributed across the Earth's surface. Each grid is defined by a set of Path / Row numbers. The Path number is the nadir trajectory number, and the Row number is the latitudinal number along the trajectory. The WRS is constructed based on satellite orbital parameters and camera swath width. Grid parameters include the number of global orbital sub-trajectories (Path numbers) and the number of scenes per orbit (Row numbers). The Path number corresponds to the number of nadir trajectories within one satellite orbital cycle, which is equal to the orbital cycle (days) multiplied by the number of orbits per day (orbits / day). The Row number is approximately equal to the Earth's north-south circumference divided by the image swath width. Based on satellite orbital parameters and WRS grid parameters, a conversion model between geographic location coordinates and grid Path / Row numbers can be established.

[0065] Cataloging a segment of data by scene based on the actual imaging geographic location and using an Earth grid system ensures that scenes with the same row number belong to the same imaging location in multi-view imaging data. This results in excellent consistency in the scene division of multi-view imaging data, meeting the production and processing requirements of stereoscopic products. If scenes are not divided according to a fixed grid, it is difficult to achieve consistency in the scene division locations of multi-view imaging data, failing to meet the production and processing requirements of stereoscopic products.

[0066] The content of each scene's Level 0 metadata includes: scene construction information, such as start line, end line, etc., used for segmenting a scene during subsequent processing; it also includes scene description information, such as satellite name, camera name, receiving station name, latitude and longitude coordinates of the four corner points and center point, path / row number, data acquisition time, cloud cover information, satellite attitude angle information at the time of shooting, Level 0 data file name, etc.; and camera status parameters, such as gain, integration level, integration time, etc.

[0067] (3) Merge the scene-specific cataloging information of each data segment by scene.

[0068] The cataloging information of each data segment is sorted in ascending order by Row number. Scene data with the same Row number are then merged to obtain a single merged cataloging information file. This file contains metadata for each scene, including information from each (multi-view) imaging session. Subsequent product manufacturing processes use this cataloging information file to retrieve Level 0 data, simultaneously obtaining multi-view data for a single scene, thus enabling the production of stereoscopic products. After the data is archived using this cataloging information file, users will also receive the multi-view metadata information for each scene when querying its data.

[0069] When merging metadata from different scenes, not all fields are merged. For example, satellite name, camera name, receiver station name, camera gain, and integration level are consistent across multi-view data. The latitude and longitude coordinates of the four corner points and the center point, path / row number, and cloud cover information are also consistent across multi-view data because they image the same area (though the imaging area may slightly differ due to flight control precision). Therefore, when merging information, only information from one single-view view is needed; multi-view merging is unnecessary.

[0070] The fields that need to be merged include:

[0071] The start and end line information, when merged, can obtain the positioning information of each view imaging data of a scene in a strip. Subsequent processing uses this information to obtain the level 0 data of each view of a scene from the strip.

[0072] Data imaging time information: Since each view images the same area sequentially, the data imaging time is different. By merging, the imaging time of each view's data can be obtained.

[0073] During the image capture, the satellite attitude angle information is obtained because each view is imaged on the same orbit by maneuvering the satellite and adjusting its attitude angle. Therefore, the attitude angles of each view are different. By combining the information, the satellite attitude angle information of each view can be obtained.

[0074] Integration time information is needed because the satellite's attitude angle differs during each view's imaging, resulting in varying pixel sizes in the ground images captured by the camera sensors. Consequently, the real-time pushbroom integration time adjusted by the satellite also varies. Merging these data allows us to obtain the center-of-field integration time information for each view's imaging.

[0075] The Level 0 data file name is used when the physical scene segmentation mode is adopted. Based on the start and end line information of the scene in the catalog file, the Level 0 data of one scene is extracted from the strip and saved. The saved file name is the agreed Level 0 data file name. After merging, the Level 0 data file names of each scene's multiple views can be obtained, which is convenient for subsequent processing modules to use.

[0076] The above-described method for segmenting and cataloging stereo imaging data of a single-line array camera along the same track involves, in step (1), segmenting the stereo imaging data of the single-line array camera along the same track, separating the data from multiple imaging of the same strip area, so that each segment of data conforms to the characteristics of continuous push-broom imaging, and can be segmented and cataloged according to the existing single-image strip data method, avoiding the jump of attitude angle when changing the view and the repetition of Row number when segmenting based on the Earth Grid System (WRS), which would lead to the inapplicability of the existing segmentation method.

[0077] The above-described method for segmenting and cataloging co-track stereo imaging data involves segmenting the single-line array camera co-track stereo imaging data in step (1). This is achieved by using timecode jumps greater than 10 seconds in the data to capture image transitions, thus segmenting the multi-view stereo imaging data. Using timecode jumps is logically simpler and easier to implement than using attitude angle jumps.

[0078] The above-described method for cataloging scene-by-scene data of a single-line array camera in a stereoscopic imaging system involves step (3) merging the scene-by-scene cataloging information of each data segment, so that the metadata information of each scene includes information from each (multi-view) imaging. Subsequent product manufacturing processes use this cataloging information to obtain level 0 data, simultaneously acquiring multi-view data for a scene, facilitating the production processing of stereoscopic products. Furthermore, when users query scene data, they can simultaneously obtain multi-view metadata information for that scene, such as the imaging time and attitude angle of each view, facilitating further data processing.

[0079] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A method for scene-by-scene cataloging of stereo imaging data from a single-line array camera on the same track, characterized in that... include: The strip data of stereo imaging from a single-line array camera is segmented by searching for time code jumps to obtain each single-image data segment. Each segment corresponds to the one-view observation data of the strip area. Specifically: a) Set the first row of the strip data as the start row of the first segment; b) Starting from the second row, parse the time code in the data row by row. If the time code of the current row minus the time code of the previous row is greater than the jump threshold, set the previous row number as the end row of the previous segment, and set the current row number as the start row of the new segment; c) Repeat step b until the strip data ends, and set the last row as the end row of the last segment; use the start and end row numbers of each segment as the segment index information; according to the start and end row numbers of each segment in the segment index information, obtain each segment data from the strip, and each segment data is the one-view observation data of the corresponding strip area. Construct a model of the current satellite Earth grid system, and catalog each segment of data based on the actual imaging geographical location to obtain the number of segments of each data segment, the nadir point trajectory number and the latitude direction number along the trajectory of each segment, and other metadata information; where the nadir point trajectory number is denoted as Path number, and the latitude direction number along the trajectory is denoted as Row number; Scenes with the same Row number are considered to be scenes at the same imaging location. The scene cataloging information results of each data segment are merged in ascending order of Row number, and the scene element information with the same Row number is merged to obtain a merged scene cataloging information file.

2. The method for scene segmentation and cataloging of stereo imaging data from a single-line array camera according to claim 1, characterized in that: The strip data of stereo imaging with a single line array camera is the result of multiple push-broom imagings of the single line array camera at a certain longitude position.

3. The method for scene segmentation and cataloging of stereo imaging data from a single-line array camera according to claim 1, characterized in that: The Earth grid system is constructed based on the satellite's orbital parameters and camera swath width. The grid parameters of the Earth grid system include Path number and Row number. The Path number corresponds to the number of nadir points within one orbital return cycle of the satellite, which is equal to the orbital return cycle multiplied by the number of orbits per day; the Row number is equal to the Earth's north-south circumference divided by the image width.

4. The method for scene segmentation and cataloging of stereo imaging data from a single-line array camera according to claim 1, characterized in that: When merging metadata information from different scenes, the fields that need to be merged include: The start and end line information are merged to obtain the positioning information of each view imaging data of a scene in a strip; The imaging time information of the data is merged to obtain the imaging time of each view data; The satellite attitude and angle information during the shooting is merged to obtain the satellite attitude and angle information for each view. The integration time information is merged to obtain the scene center line integration time information of each view image; The Level 0 data file name is the agreed-upon Level 0 data file name when using the physical scene segmentation mode. It is extracted from the strip based on the start and end line information of the scene in the catalog file.

5. The method for scene segmentation and cataloging of stereo imaging data from a single-line array camera along the same track according to claim 1, characterized in that: In the merged catalog information file, the metadata information for each scene includes information on multi-view imaging.

6. A scene-by-scene cataloging system for stereo imaging data of a single-line array camera on the same track, based on the scene-by-scene cataloging method for stereo imaging data of a single-line array camera as described in claim 1, characterized in that... include: Imaging data segmentation module: The strip data of the same track stereo imaging of a single line array camera is segmented by searching for time code jumps to obtain each single imaging data segment; The specific process is as follows: a) Set the first row of the strip data as the start row of the first segment; b) Starting from the second row, parse the timecode in the data row by row. If the timecode of the current row minus the timecode of the previous row is greater than the jump threshold, set the previous row number as the end row of the previous segment, and set the current row number as the start row of the new segment; c) Repeat step b until the strip data ends, and set the last row as the end row of the last segment; use the start row number and end row number of each segment as the segment index information; according to the start row and end row number of each segment in the segment index information, obtain the data of each segment from the strip, and each segment of data is the one-look observation data of the corresponding strip area; Scene-by-scene cataloging module: Based on the pre-constructed current satellite Earth grid system model, each data segment is cataloged according to the actual imaging geographical location, resulting in the number of scenes for each data segment, the nadir point trajectory number and the Path / Row number along the trajectory, and other metadata information; where the nadir point trajectory number is denoted as Path number, and the latitudinal number along the trajectory is denoted as Row number; Scene data merging module: Merges the scene cataloging information results of each segment of data in ascending order of Row number, and merges the scene data information with the same Row number to obtain a merged cataloging information file.

7. A scene-by-scene cataloging system for stereoscopic imaging data of a single-line array camera according to claim 6, characterized in that: When merging scene metadata information, the fields that need to be merged by the scene metadata merging module include: The start and end line information are merged to obtain the positioning information of each view imaging data of a scene in a strip; The imaging time information of the data is merged to obtain the imaging time of each view data; The satellite attitude and angle information during the shooting is merged to obtain the satellite attitude and angle information for each view. The integration time information is merged to obtain the scene center line integration time information of each view image; The Level 0 data file name is the agreed-upon Level 0 data file name when using the physical scene segmentation mode. It is extracted from the strip based on the start and end line information of the scene in the catalog file.