用python生成无人机影像的正射影像、数字高程模型以及三维建模

朱雀 2023-05-30 03:58 429阅读 0赞

# OpenDroneMap #

[OpenDroneMap][] 是一个开源的航拍图像处理工具，可以把航拍图像进行点云、正射影像和高程模型等处理，也可以做3维重构，生成3维模型。简直是个神器，做出来的效果和pix4d等软件差不多（我目前只做了无人机影像的正摄影像的生成）。  
  根据官方文档所说，PyODM可以很轻易的创建无人机影像的正射图，DEM,3d模型以及点云。  
  正射图的效果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE2MjI0MA_size_16_color_FFFFFF_t_70]  
  下面开始使用OpenDroneMap的python库[PyODM][]。  
  注：若图片内有exif信息，则odm可以直接生成tif的正射影像。给图片添加exif信息可以参看下面这篇博客。  
[https://blog.csdn.net/weixin\_43162240/article/details/103579657][https_blog.csdn.net_weixin_43162240_article_details_103579657]

## 1.环境准备 ##

### 安装pyodm包 ###

用pip安装即可。

pip install -U pyodm

### 启动docker ###

pyodm需要启动docker，所以在使用之前还需要先安装docker.  
windows的安装就不说了，可以自行百度,下面介绍linux系统下docker的安装。

# 安装docker
    $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
    $ sudo apt-get install -y docker-ce
    
    # 启动docker，这里会自己下载需要的包，所以需要等待一会儿。
    $ sudo docker run -ti -p 3000:3000 opendronemap/nodeodm

## 2.python教程 ##

大致流程是这样，先连接Node，然后新建任务，然后等待任务执行完成，最后获取结果。  
  这里关键是新建任务时有个option选项，可以设置一些配置。看[文档说明][Link 1]得知，配置会影响处理速度与结果的质量。  
  对正射影像的制作来说，需要配置的一些参数(参数可以在[官方文档][Link 2]查看)如下：

*  orthophoto-resolution：米/像素，表示地面分辨率
 *  dsm：是否要生成dsm，如果不需要的话，选false会加快处理速度
 *  ignore-gsd：设置为True就会跳过一些加速处理，得到的图像质量会好一些
 *  min-num-features：找的特征点数量，数量越多质量越好，处理时间越长
 *  texturing-nadir-weight：官方建议，在都市设为29-32，草地或者平底设置为0-6
 *  mesh-octree-depth：官方建议设置为10-11，增加建筑屋顶的平滑性。

注意：在制作正射影像时，选择的图片最好是有至少两个轨道的数据，一个航线的数据拼接会失败，即task.wait\_for\_completion()会返回failed.

import os
    from pyodm import Node
    import time
    from tqdm import tqdm
    
    
    image_dir = 'testdata/'
    result_path = image_dir.split('/')[0]+'_results'
    ip = 'xxx.xx.xx.xx' # 改为自己的ip
    port = 3000
    
    start = time.time()
    images_name = os.listdir(image_dir)
    images_name = [image_dir+image_name for image_name in images_name]
    print(images_name)
    
    n = Node(ip, port)
    print("Node连接成功，{}张图开始处理".format(len(images_name)))
    
    
    task = n.create_task(images_name, {'orthophoto-resolution': 0.0274,"min-num-features":35000})
    print("任务创建完成")
    pbar = tqdm(total=100)
    processing = 0
    while True:
        info = task.info()
        if info.progress==100:
            break
        pbar.update(info.progress-processing)
        processing = info.progress
        if info.last_error!='':
            print("error ", info.last_error)
            
        time.sleep(0.1)
    pbar.close()
    
    print("处理完成")
    # task.wait_for_completion()
    task.download_assets(result_path)
    
    print("{}张图消耗{}秒".format(len(images_name), time.time() - start))

## 3.其它 ##

查看官方文档可能需要科学上网，所以把option列出来了。

-h, --help            show this help message and exit
    --images <path>, -i <path>
                          Path to input images
    --project-path <path>
                          Path to the project folder
    --resize-to <integer>
                          resizes images by the largest side for opensfm. Set to
                          -1 to disable.
                                                  Default: 2048
    --end-with <string>, -e <string>
                          Can be one of:dataset | split | merge | opensfm | mve
                          | odm_filterpoints | odm_meshing | mvs_texturing |
                          odm_georeferencing | odm_dem | odm_orthophoto
    --rerun <string>, -r <string>
                          Can be one of:dataset | split | merge | opensfm | mve
                          | odm_filterpoints | odm_meshing | mvs_texturing |
                          odm_georeferencing | odm_dem | odm_orthophoto
    --rerun-all           force rerun of all tasks
    --rerun-from <string>
                          Can be one of:dataset | split | merge | opensfm | mve
                          | odm_filterpoints | odm_meshing | mvs_texturing |
                          odm_georeferencing | odm_dem | odm_orthophoto
    --proj <PROJ4 string>
                          Projection used to transform the model into geographic
                          coordinates
    --min-num-features <integer>
                          Minimum number of features to extract per image. More
                          features leads to better results but slower execution.
                          Default: 8000
    --matcher-neighbors <integer>
                          Number of nearest images to pre-match based on GPS
                          exif data. Set to 0 to skip pre-matching. Neighbors
                          works together with Distance parameter, set both to 0
                          to not use pre-matching. OpenSFM uses both parameters
                          at the same time, Bundler uses only one which has
                          value, prefering the Neighbors parameter.
                                                  Default: 8
    --matcher-distance <integer>
                          Distance threshold in meters to find pre-matching
                          images based on GPS exif data. Set both matcher-
                          neighbors and this to 0 to skip pre-matching.
                                                  Default: 0
    --use-fixed-camera-params
                          Turn off camera parameter optimization during bundler
                                                  Off by default unless --camera parameter used
    --camera-lens <string>
                          Can be one of auto | perspective | brown | fisheye | spherical
                          Set a camera projection type. Manually setting a value
                          can help improve geometric undistortion. By default the application
                          tries to determine a lens type from the images metadata.
                                                  Default: auto
    --max-concurrency <positive integer>
                          The maximum number of processes to use in various
                          processes. Peak memory requirement is ~1GB per thread
                          and 2 megapixel image resolution.
                                                  Default: number of cores
    --depthmap-resolution <positive float>
                          Controls the density of the point cloud by setting the
                          resolution of the depthmap images. Higher values take
                          longer to compute and more memory but produce denser
                                                  point clouds.
                          Default: 640
    --opensfm-depthmap-min-consistent-views <integer: 2 <= x <= 9>
                          Minimum number of views that should reconstruct a
                          point for it to be valid. Use lower values if your
                          images have less overlap. Lower values result in
                          denser point clouds but with more noise. Only applies
                                                  if using OpenSfM for dense matching.
                                                  Default: 3
    --opensfm-depthmap-method <string>
                          Raw depthmap computation algorithm. PATCH_MATCH and
                          PATCH_MATCH_SAMPLE are faster, but might miss some
                          valid points. BRUTE_FORCE takes longer but produces
                          denser reconstructions.
                                                  Default: PATCH_MATCH
    --opensfm-depthmap-min-patch-sd <positive float>
                          When using PATCH_MATCH or PATCH_MATCH_SAMPLE, controls
                          the standard deviation threshold to include patches.
                          Patches with lower standard deviation are ignored.
                          Default: 1
    --use-hybrid-bundle-adjustment
                          Run local bundle adjustment for every image added to
                          the reconstruction and a global adjustment every 100
                          images. Speeds up reconstruction for very large
                          datasets.
    --mve-confidence <float: 0 <= x <= 1>
                          Discard points that have less than a certain
                          confidence threshold. This only affects dense
                          reconstructions performed with MVE. Higher values
                          discard more points.
                                                  Default: 0.6
    --use-3dmesh          Use a full 3D mesh to compute the orthophoto instead
                          of a 2.5D mesh. This option is a bit faster and
                          provides similar results in planar areas.
    --skip-3dmodel        Skip generation of a full 3D model. This can save time
                          if you only need 2D results such as orthophotos and
                          DEMs.
    --use-opensfm-dense   Use opensfm to compute dense point cloud alternatively
    --ignore-gsd          Ignore Ground Sampling Distance (GSD). GSD caps the
                          maximum resolution of image outputs and resizes images
                          when necessary, resulting in faster processing and
                          lower memory usage. Since GSD is an estimate,
                          sometimes ignoring it can result in slightly better
                          image output quality.
    --mesh-size <positive integer>
                          The maximum vertex count of the output mesh.
                                                  Default: 100000
    --mesh-octree-depth <positive integer>
                          Oct-tree depth used in the mesh reconstruction,
                          increase to get more vertices, recommended values are
                          8-12.
                                                  Default: 9
    --mesh-samples <float >= 1.0>
                          Number of points per octree node, recommended and
                          Default: 1.0
    --mesh-point-weight <positive float>
                          This floating point value specifies the importance
                          that interpolation of the point samples is given in
                          the formulation of the screened Poisson equation. The
                          results of the original (unscreened) Poisson
                          Reconstruction can be obtained by setting this value
                          to 0.
                                                  Default: 4
    --fast-orthophoto     Skips dense reconstruction and 3D model generation. It
                          generates an orthophoto directly from the sparse
                          reconstruction. If you just need an orthophoto and do
                          not need a full 3D model, turn on this option.
                          Experimental.
    --crop <positive float>
                          Automatically crop image outputs by creating a smooth
                          buffer around the dataset boundaries, shrinked by N
                          meters. Use 0 to disable cropping.
                                                  Default: 3
    --pc-classify         Classify the point cloud outputs using a Simple
                          Morphological Filter. You can control the behavior of
                          this option by tweaking the --dem-* parameters.
                          Default: False
    --pc-csv              Export the georeferenced point cloud in CSV format.
                          Default: False
    --pc-las              Export the georeferenced point cloud in LAS format.
                          Default: False
    --pc-filter <positive float>
                          Filters the point cloud by removing points that
                          deviate more than N standard deviations from the local
                          mean. Set to 0 to disable filtering.
                                                  Default: 2.5
    --smrf-scalar <positive float>
                          Simple Morphological Filter elevation scalar
                          parameter.
                                                  Default: 1.25
    --smrf-slope <positive float>
                          Simple Morphological Filter slope parameter (rise over
                          run).
                                                  Default: 0.15
    --smrf-threshold <positive float>
                          Simple Morphological Filter elevation threshold
                          parameter (meters).
                                                  Default: 0.5
    --smrf-window <positive float>
                          Simple Morphological Filter window radius parameter
                          (meters).
                                                  Default: 18.0
    --texturing-data-term <string>
                          Data term: [area, gmi].
                                                  Default: gmi
    --texturing-nadir-weight <integer: 0 <= x <= 32>
                          Affects orthophotos only. Higher values result in
                          sharper corners, but can affect color distribution and
                          blurriness. Use lower values for planar areas and
                          higher values for urban areas. The default value works
                          well for most scenarios.
                                                  Default: 16
    --texturing-outlier-removal-type <string>
                          Type of photometric outlier removal method: [none,
                          gauss_damping, gauss_clamping].
                                                  Default: gauss_clamping
    --texturing-skip-visibility-test
                          Skip geometric visibility test.
                                                  Default: False
    --texturing-skip-global-seam-leveling
                          Skip global seam leveling. Useful for IR data.
                                                  Default: False
    --texturing-skip-local-seam-leveling
                          Skip local seam blending.
                                                  Default: False
    --texturing-skip-hole-filling
                          Skip filling of holes in the mesh.
                                                  Default: False
    --texturing-keep-unseen-faces
                          Keep faces in the mesh that are not seen in any
                          camera.
                                                  Default: False
    --texturing-tone-mapping <string>
                          Turn on gamma tone mapping or none for no tone
                          mapping. Choices are 'gamma' or 'none'.
                                                  Default: none
    --gcp <path string>   path to the file containing the ground control points
                          used for georeferencing. Default: None. The file needs
                          to be on the following line format: easting northing
                          height pixelrow pixelcol imagename
    --use-exif            Use this tag if you have a gcp_list.txt but want to
                          use the exif geotags instead
    --dtm                 Use this tag to build a DTM (Digital Terrain Model,
                          ground only) using a simple morphological filter.
                          Check the --dem* and --smrf* parameters for finer
                          tuning.
    --dsm                 Use this tag to build a DSM (Digital Surface Model,
                          ground + objects) using a progressive morphological
                          filter. Check the --dem* parameters for finer tuning.
    --dem-gapfill-steps <positive integer>
                          Number of steps used to fill areas with gaps. Set to 0
                          to disable gap filling. Starting with a radius equal
                          to the output resolution, N different DEMs are
                          generated with progressively bigger radius using the
                          inverse distance weighted (IDW) algorithm and merged
                          together. Remaining gaps are then merged using nearest
                          neighbor interpolation.
                                                  Default: 3
    --dem-resolution <float>
                          DSM/DTM resolution in cm / pixel.
                                                  Default: 5
    --dem-decimation <positive integer>
                          Decimate the points before generating the DEM. 1 is no
                          decimation (full quality). 100 decimates ~99% of the
                          points. Useful for speeding up generation.
                                                  Default: 1
    --dem-euclidean-map   Computes an euclidean raster map for each DEM. The map
                          reports the distance from each cell to the nearest
                          NODATA value (before any hole filling takes place).
                          This can be useful to isolate the areas that have been
                          filled.
                                                  Default: False
    --orthophoto-resolution <float > 0.0>
                          Orthophoto resolution in cm / pixel.
                                                  Default: 5
    --orthophoto-no-tiled
                          Set this parameter if you want a stripped geoTIFF.
                          Default: False
    --orthophoto-compression <string>
                          Set the compression to use. Note that this could break
                          gdal_translate if you don't know what you are doing.
                          Options: JPEG, LZW, PACKBITS, DEFLATE, LZMA, NONE.
                          Default: DEFLATE
    --orthophoto-bigtiff {YES,NO,IF_NEEDED,IF_SAFER}
                          Control whether the created orthophoto is a BigTIFF or
                          classic TIFF. BigTIFF is a variant for files larger
                          than 4GiB of data. Options are YES, NO, IF_NEEDED,
                          IF_SAFER. See GDAL specs:
                          https://www.gdal.org/frmt_gtiff.html for more info.
                          Default: IF_SAFER
    --orthophoto-cutline  Generates a polygon around the cropping area that cuts
                          the orthophoto around the edges of features. This
                          polygon can be useful for stitching seamless mosaics
                          with multiple overlapping orthophotos.
                                                  Default: False
    --build-overviews     Build orthophoto overviews using gdaladdo.
    --verbose, -v         Print additional messages to the console
                                                  Default: False
    --time                Generates a benchmark file with runtime info
                                                  Default: False
    --version             Displays version number and exits.
    --split <positive integer>
                          Average number of images per submodel. When splitting
                          a large dataset into smaller submodels, images are
                          grouped into clusters. This value regulates the number
                          of images that each cluster should have on average.
    --split-overlap <positive integer>
                          Radius of the overlap between submodels. After
                          grouping images into clusters, images that are closer
                          than this radius to a cluster are added to the
                          cluster. This is done to ensure that neighboring
                          submodels overlap.
    --sm-cluster <string>
                          URL to a ClusterODM instance for distributing a
                          split-merge workflow on multiple nodes in parallel.
                          Default: None
    --merge <string>      Choose what to merge in the merge step in a split
                          dataset. By default all available outputs are merged.
                          Default: all

[OpenDroneMap]: https://github.com/OpenDroneMap
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE2MjI0MA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191108205935420.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzE2MjI0MA==,size_16,color_FFFFFF,t_70
[PyODM]: https://pyodm.readthedocs.io/en/latest/#pyodm.api.Node.create_task
[https_blog.csdn.net_weixin_43162240_article_details_103579657]: https://blog.csdn.net/weixin_43162240/article/details/103579657
[Link 1]: https://docs.opendronemap.org/tutorials.html
[Link 2]: https://docs.opendronemap.org/arguments.html