This tool can be used when processing Digital Globe images
(Section 5). Such an image product may be packaged
as several sub-images and corresponding camera XML
dg_mosaic will mosaic these sub-images into a single file, and
create the appropriate combined camera XML file.
The tool needs to be applied to the sub-images which form the left
image, and then in the same way to obtain the right image. These can
then be passed to
parallel_stereo (Section 16.47).
Digital Globe camera files contain, in addition to the original camera
models, their RPC approximations (Section 8.19).
dg_mosaic outputs both types of combined models. The combined RPC
model can be used to mapproject the mosaicked images with the goal of
computing stereo from them (Section 6.1.7).
dg_mosaic can also reduce the image resolution while creating the
mosaics (with the camera files modified accordingly).
Some older (2009 or earlier) Digital Globe images may exhibit seams upon
mosaicking due to inconsistent image and camera information. The
--fix-seams switch can be used to rectify this problem. Its effect
should be minimal if such inconsistencies are not present.
Digital Globe images can be used as they are as well, but in that case each left sub-image needs to be paired up with one more more right sub-images, create individual DEMs, and then mosaic those into a single output DEM. Hence this program simplifies the data processing.
Only level 1B images are supported (see the product info).
This will create
r.100 stands for the full
Care should be taken to not mosaic together PAN and multispectral
images, which have
M1BS as part of their names.
Command-line options for dg_mosaic:
- -h, --help
Display the help message.
Choose the output resolution in meters per pixel on the ground (note that a coarse resolution may result in aliasing).
- --reduce-percent <integer (default: 100)>
Render a reduced resolution image and XML based on this percentage. This can result in aliasing artifacts.
Skip RPC model generation.
Skip TIF file generation.
- --rpc-penalty-weight <float (default: 0.1)>
The weight to use to penalize higher order RPC coefficients when generating the combined RPC model. Higher penalty weight results in smaller such coefficients.
- --output-prefix <name>
The prefix for the output .tif and .xml files.
- --cache-size-mb <integer (default = 1024)>
Set the system cache size, in MB, for each process.
- --band integer
Which band to use (for multi-spectral images).
- --input-nodata-value <float>
Nodata value to use on input; input pixel values less than or equal to this are considered invalid.
- --output-nodata-value <float>
Nodata value to use on output.
- --ot <Byte|UInt16|Int16|UInt32|Int32|Float32 (default: Float32)>
Output data type. If the output type is a kind of integer, values are rounded and then clamped to the limits of that type.
Fix seams in the output mosaic due to inconsistencies between image and camera data using interest point matching.
Ignore the fact that some of the files to be mosaicked have inconsistent EPH/ATT values. Do this at your own risk.
Render a small 8 bit png of the input for preview.
- -n, --dry-run
Make calculations, but just print out the commands.