StereoFramework¶
基于一个或多个立体对计算地面高程(S)
描述¶
使用传感器几何中一个或多个立体对之间的立体块匹配算法计算地面高程。输出以所需的地理或地图投影(默认情况下为WGS84)进行投影。
此应用程序正在链接不同的处理步骤。其中一些还由立体重建框架中的其他应用程序执行：
- StereoRectificationGridGenerator ：用于生成变形栅格
- GridBasedImageResampling ：重采样到对极几何体
- BlockMatching ：稠密视差图的估计
流水线对每个立体声对执行以下步骤：
- 从立体声对(正向和逆)计算极线位移网格
- 使用BCO插值法将立体对重采样为对极几何图形
- 为每个核线图像创建遮罩：删除黑色边框并重新采样输入遮罩
- 使用块匹配算法计算水平视差
- 使用二分法将视差细化到亚像素精度
- 应用可选中值滤波
- 基于相关性分数和勘探边界过滤差异
- 平移传感器几何图形中的差异
- 将视差转换为3D地图。
然后，将所有的3D地图进行融合，生成DSM。每个DEM单元的融合方法可以在最大值、最小值和平均值之间选择。
参数¶
输入参数¶
这组参数允许设置输入数据。
Input images list -input.il image1 image2... Mandatory
List of images corresponding to multiple views on a single scene, in sensor geometry.
Couples list -input.co string
List of index of couples im image list. Couples must be separated by a comma (index start at 0). For example: 0 1,1 2 will process a first couple composed of the first and the second image in image list, then the second and the third image
. Note that images are handled by pairs. If left empty, couples are created from input index i.e. a first couple will be composed of the first and second image, a second couple with third and fourth image etc. (in this case image list must be even).
Input Image channel -input.channel int Default value: 1
Channel used for block matching (the same for all images)
高程管理¶
这组参数允许管理高程值。
DEM directory -elev.dem directory
This parameter allows selecting a directory containing Digital Elevation Model files. Note that this directory should contain only DEM files. Unexpected behaviour might occurs if other images are found in this directory. Input DEM tiles should be in a raster format supported by GDAL.
Geoid File -elev.geoid filename [dtype]
Use a geoid grid to get the height above the ellipsoid in case there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles. A version of the geoid can be found on the OTB website (egm96.grd and egm96.grd.hdr at https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb/-/tree/master/Data/Input/DEM).
Default elevation -elev.default float Default value: 0
This parameter allows setting the default height above ellipsoid when there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles, and no geoid file has been set. This is also used by some application as an average elevation value.
输出参数¶
这组参数允许选择DSM分辨率、nodata值和投影参数。
Output resolution -output.res float Default value: 1
Spatial sampling distance of the output elevation: the cell size (in m)
NoData value -output.nodata float Default value: -32768
DSM empty cells are filled with this value (optional -32768 by default)
Method to fuse measures in each DSM cell -output.fusionmethod [max|min|mean|acc] Default value: max
This parameter allows one to choose the method used to fuse elevation measurements in each output DSM cell
- Maximum
The cell is filled with the maximum measured elevation values - Minimum
The cell is filled with the minimum measured elevation values - Mean
The cell is filled with the mean of measured elevation values - Accumulator
Accumulator mode. The cell is filled with the the number of values (for debugging purposes).
Output DSM -output.out image [dtype] Mandatory
Output elevation image
Parameters estimation modes -output.mode [fit|user] Default value: fit
- Fit to sensor image
Fit the size, origin and spacing to an existing ortho image (uses the value of outputs.ortho) - User Defined
This mode allows you to fully modify default values.
用户定义的选项¶
Upper Left X -output.mode.user.ulx float Mandatory
Cartographic X coordinate of upper-left corner (meters for cartographic projections, degrees for geographic ones)
Upper Left Y -output.mode.user.uly float Mandatory
Cartographic Y coordinate of the upper-left corner (meters for cartographic projections, degrees for geographic ones)
Size X -output.mode.user.sizex int Mandatory
Size of projected image along X (in pixels)
Size Y -output.mode.user.sizey int Mandatory
Size of projected image along Y (in pixels)
Pixel Size X -output.mode.user.spacingx float Mandatory
Size of each pixel along X axis (meters for cartographic projections, degrees for geographic ones)
Pixel Size Y -output.mode.user.spacingy float Mandatory
Size of each pixel along Y axis (meters for cartographic projections, degrees for geographic ones)
Map Projection -map [utm|lambert2|lambert93|wgs|epsg] Default value: wgs
Defines the map projection to be used.
- Universal Trans-Mercator (UTM)
A system of transverse mercator projections dividing the surface of Earth between 80S and 84N latitude. - Lambert II Etendu
This is a Lambert Conformal Conic projection mainly used in France. - Lambert93
This is a Lambert 93 projection mainly used in France. - WGS 84
This is a Geographical projection - EPSG Code
This code is a generic way of identifying map projections, and allows specifying a large amount of them. See www.spatialreference.org to find which EPSG code is associated to your projection;
通用跨墨卡托(UTM)选项¶
Zone number -map.utm.zone int Default value: 31
The zone number ranges from 1 to 60 and allows defining the transverse mercator projection (along with the hemisphere)
Northern Hemisphere -map.utm.northhem bool Default value: false
The transverse mercator projections are defined by their zone number as well as the hemisphere. Activate this parameter if your image is in the northern hemisphere.
EPSG代码选项¶
EPSG Code -map.epsg.code int Default value: 4326
See www.spatialreference.org to find which EPSG code is associated to your projection
立体校正栅格参数¶
这组参数允许选择直接网格子采样和逆网格子采样。这些参数对于调整时间和内存消耗非常有用。
Step of the displacement grid (in pixels) -stereorect.fwdgridstep int Default value: 16
Stereo-rectification displacement grid only varies slowly. Therefore, it is recommended to use a coarser grid (higher step value) in case of large images
Sub-sampling rate for epipolar grid inversion -stereorect.invgridssrate int Default value: 10
Grid inversion is an heavy process that implies spline regression on control points. To avoid eating to much memory, this parameter allows one to first sub-sample the field to invert.
块匹配参数¶
这组参数允许调整块匹配行为
Block-matching metric -bm.metric [ssdmean|ssd|ncc|lp] Default value: ssdmean
Metric used to compute matching score
- Sum of Squared Distances divided by mean of block
derived version of Sum of Squared Distances between pixels value in the metric window (SSD divided by mean over window) - Sum of Squared Distances
Sum of squared distances between pixels value in the metric window - Normalized Cross-Correlation
Normalized Cross-Correlation between the left and right windows - Lp pseudo-norm
Lp pseudo-norm between the left and right windows
Lp伪范数期权¶
p value -bm.metric.lp.p float Default value: 1
Value of the p parameter in Lp pseudo-norm (must be positive)
Correlation window radius (in pixels) -bm.radius int Default value: 2
The radius of blocks in Block-Matching (in pixels)
Minimum altitude offset (in meters) -bm.minhoffset float Default value: -20
Minimum altitude below the selected elevation source (in meters)
Maximum altitude offset (in meters) -bm.maxhoffset float Default value: 20
Maximum altitude above the selected elevation source (in meters)
后处理参数¶
这组参数允许使用可选过滤器。
Use bijection consistency in block matching strategy -postproc.bij bool Default value: true
Use bijection consistency. Right to Left correlation is computed to validate Left to Right disparities. If bijection is not found, the disparity is rejected.
Use median disparities filtering -postproc.med bool Default value: false
Disparity map can be filtered using median post filtering (disabled by default).
Correlation metric threshold -postproc.metrict float Default value: 0.6
Use block matching metric output to discard pixels with low correlation value (disabled by default, float value)
面具¶
Input left mask -mask.left image
Mask for left input image. Pixel with a null mask value are discarded.
Input right mask -mask.right image
Mask for right input image. Pixel with a null mask value are discarded.
Discard pixels with low local variance -mask.variancet float Default value: 50
This parameter allows one to discard pixels whose local variance is too small (the size of the neighborhood is given by the correlation window radius)
Available RAM (MB) -ram int Default value: 256
Available memory for processing (in MB).
实例¶
从命令行执行以下操作：
otbcli_StereoFramework -input.il sensor_stereo_left.tif sensor_stereo_right.tif -elev.default 200 -stereorect.fwdgridstep 8 -stereorect.invgridssrate 4 -postproc.med 1 -output.res 2.5 -output.out dem.tif
来自Python的评论：
import otbApplication
app = otbApplication.Registry.CreateApplication("StereoFramework")
app.SetParameterStringList("input.il", ['sensor_stereo_left.tif', 'sensor_stereo_right.tif'])
app.SetParameterFloat("elev.default", 200)
app.SetParameterInt("stereorect.fwdgridstep", 8)
app.SetParameterInt("stereorect.invgridssrate", 4)
app.SetParameterString("postproc.med","1")
app.SetParameterFloat("output.res", 2.5)
app.SetParameterString("output.out", "dem.tif")
app.ExecuteAndWriteOutput()