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README.rst

MAP-Tk

/gui/icons/64x64/telesculptor.png

Motion-imagery Aerial Photogrammetry Toolkit

MAP-Tk started as an open source C++ collection of libraries and tools for making measurements from aerial video. Initial capability focused on estimating the camera flight trajectory and a sparse 3D point cloud of a scene. These products are jointly optimized via sparse bundle adjustment and are geo-localized if given additional control points or GPS metadata.

This project has similar goals as projects like Bundler and VisualSFM. However, the focus here in on efficiently processing aerial video rather than community photo collections. Special attention has been given to the case where the variation in depth of the 3D scene is small compared to distance to the camera. In these cases, planar homographies can be used to assist feature tracking, stabilize the video, and aid in solving loop closure problems.

MAP-Tk uses the KWIVER software architecture. Originally developed for MAP-Tk, KWIVER is highly modular and provides an algorithm abstraction layer that allows seamless interchange and run-time selection of algorithms from various other open source projects like OpenCV, VXL, Ceres Solver, and PROJ4. The core library and tools are light-weight with minimal dependencies (C++ standard library, KWIVER vital, and Eigen). The tools are written to depend only on the MAP-Tk and KWIVER vital libraries. Additional capabilities are provided by KWIVER arrows (plugin modules) that use third party libraries to implement various abstract algorithm interfaces defined in the KWIVER vital library. Earlier versions of MAP-Tk contained these core data structures, algorithms, and plugins, but these have since been moved to KWIVER for easier reuse across projects. What remains in this repository are the tools, scripts, and applications required to apply KWIVER algorithms to photogrammetry problems. As MAP-Tk capabilities have continued to migrate up into KWIVER this repository has become less of a "toolkit" and more of an end user application that uses the KWIVER toolkit. Additionally the capabilities are starting to branch out beyond aerial data. As a result, we are transitioning away from the MAP-Tk name as this repository becomes more about the GUI application named TeleSculptor.

TeleSculptor is a GUI application built on Qt. It provides a graphical interface to run photogrammetry algorithms and assist with visualization of data and results with the help of VTK. The screenshots below show TeleSculptor running on example videos from the VIRAT Video Dataset, CLIF 2007 Dataset, and other public data sets. More information about this example data can be found in the examples directory.

MacOS Screenshot

Windows Screenshot

Linux Screenshot

TeleSculptor now supports visualization of depth maps, but compution of depth maps is not yet supported by KWIVER. Instead, the cameras computed by MAP-Tk can be used with a fork of PlaneSweepLib that reads in the cameras and images and produces depthmaps that the GUI can load. We are working on extending MAP-Tk TeleSculptor to compute depth maps directly.

While the initial software implementation relies on batch post-processing of aerial video, our intent is to move to an online video stream processing framework and optimize the algorithm to run in real-time.

Overview of Directories

CMake contains CMake helper scripts
config contains reusable default algorithm configuration files
doc contains release notes, manuals, and other documentation
examples contains example tool configuration for public datasets
gui contains the visualization GUI source code and headers
gui/icons contains the visualization GUI icon resources
maptk contains the maptk library source and headers
packaging contains support files for CPack packaging
scripts contains Python helper scripts
scripts/blender contains Python plug-ins for Blender
tests contains testing framework and tests for each module
tools contains source for command line utilities

Building MAP-Tk

MAP-Tk uses CMake (www.cmake.org) for easy cross-platform compilation. The minimum required version of CMake is 3.0, but newer versions are recommended.

As with KWIVER, MAP-Tk requires C++11 compliant compiler (e.g. GCC 4.8, Visual Studio 2015).

Running CMake

We recommend building MAP-Tk out of the source directory to prevent mixing source files with compiled products. Create a build directory in parallel with the MAP-Tk source directory. From the command line, enter the empty build directory and run:

$ ccmake /path/to/maptk/source

where the path above is the location of your MAP-Tk source tree. The ccmake tool allows for interactive selection of CMake options. Alternatively, using the CMake GUI you can set the source and build directories accordingly and press the "Configure" button.

CMake Options

CMAKE_BUILD_TYPE The compiler mode, usually Debug or Release
CMAKE_INSTALL_PREFIX The path to where you want MAP-Tk to install
MAPTK_ENABLE_MANUALS Turn on building the user documentation (manuals)
MAPTK_ENABLE_DOCS Turn on building the Doxygen documentation
MAPTK_INSTALL_DOCS Install Doxygen documentation (requires above enabled)
MAPTK_ENABLE_TESTING Build the unit tests
kwiver_DIR Path to the KWIVER build or install tree
qtExtensions_DIR Path to the QtExtension build or install tree

Dependencies

MAP-Tk has minimal required dependencies at the core level. Enabling plugins adds additional capabilities as well as additional dependencies. Some functionality is duplicated between modules to provide choices. Feature tracking requires OpenCV or VisCL. Bundle adjustment requires Ceres Solver or VXL. Geographic transformations require PROJ4.

Required

The only hard dependencies of MAP-Tk are on the C++ standard library, KWIVER (≥ 1.1), and Eigen (≥ 3.0; also required by KWIVER).

Recommended KWIVER Plugins

When building KWIVER for use in MAP-Tk there are several arrows (plugins) that should be enabled to provide maximum capability to MAP-Tk. The KWIVER arrows are not a build-time dependency of MAP-Tk, but are required at run-time to provide algorithm implementations to run. The following KWIVER arrows provide algorithms which are optionally used by MAP-Tk:

  • Core
    algorithm implementations with no additional dependencies
  • Ceres
    supplies bundle adjustment using Ceres Solver http://ceres-solver.org/
  • OpenCV
    supplies feature detectors, descriptors, matcher; homography and fundamental matrix estimators; image I/O, and more. http://opencv.org/
  • PROJ
    provides geographic transforms (e.g. Lat/Lon to UTM) http://trac.osgeo.org/proj/:
  • VisCL
    experimental code for OpenCL acceleration (currently not recommend for most users) https://github.com/Kitware/VisCL
  • VXL
    supplies a simple bundle adjuster, image I/O, homgraphy and fundamental matrix estimation, and more. (note: requires unreleased version, use Fletch to build) http://vxl.sourceforge.net/
TeleSculptor

The MAP-Tk TeleSculptor GUI application is an optional (but recommended) part of the MAP-Tk build. It has additional dependencies. To build the TeleSculptor, you need:

Most of the dependencies for KWIVER and MAP-Tk can be provided by a meta-project called Fletch. Fletch uses CMake to fetch, configure, and build various third party packages such that they work together in a consistent way across platforms. We recommend that you use Fletch to build Ceres, Eigen, OpenCV, PROJ, Qt, VTK, and VXL and their dependencies. Next build KWIVER and set "fletch_DIR" in CMake to point to your Fletch build. Enable the arrows recommended above in the KWIVER build. Finally, build MAP-Tk and set "kwiver_DIR" in CMake to point to your KWIVER build.

Documentation

Documentation generation is another optional component that brings in additional dependencies. To build the API documentation, you need:

To build the user manual(s), you need:

(At present, only the GUI has a user manual. Other manuals may be added in the future.)

Nightly builds of the Doxygen documentation for the primary branches are here:

Nightly master Documentation http://www.kwiver.org/maptk/docs/nightly/master
Nightly release Documentation http://www.kwiver.org/maptk/docs/nightly/release

Doxygen documentation for released versions are here:

MAP-Tk v0.6.1 Documentation http://www.kwiver.org/maptk/docs/release/v0.6.1
MAP-Tk v0.7.2 Documentation http://www.kwiver.org/maptk/docs/release/v0.7.2
MAP-Tk v0.8.1 Documentation http://www.kwiver.org/maptk/docs/release/v0.8.1
MAP-Tk v0.9.0 Documentation http://www.kwiver.org/maptk/docs/release/v0.9.0

Building Documentation

If MAPTK_ENABLE_DOCS is enabled, and CMake finds, or is provided with, a path to the Doxygen tool, then the HTML documentation is built as part of the normal build process under the target "doxygen". Open ${MAPTK_BUILD_DIR}/docs/index.html in your browser to view the documentation.

If MAPTK_ENABLE_MANUALS is enabled, and CMake finds, or is provided with, a path to the Python executable which is able to import docutils, then the user manuals are built as part of the normal build process under the target "manuals". The GUI manual can be viewed from inside the GUI by choosing the "MAP-Tk TeleSculptor User Manual" action from the "Help" menu.

Testing

Continuous integration testing is provided by CDash. Our MAP-Tk dashboard hosts nightly build and test results across multiple platforms including Windows, Mac, and Linux.

Anyone can contribute a build to this dashboard using the dashboard script provided. Follow the instructions in the comments.

Travis CI is also used for continued integration testing. Travis CI is limited to a single platform (Ubuntu Linux), but provides automated testing of all topic branches and pull requests whenever they are created.

Travis CI master branch: CI:master
Travis CI release branch: CI:release

MAP-Tk Tools

MAP-Tk command line tools are placed in the bin directory of the build or install path. These tools are described below.

Summary of MAP-Tk Tools

The primary tools are maptk_track_features and maptk_bundle_adjust_tracks. Together these form the sparse bundle adjustment pipeline. The other tools are for debugging and analysis purposes.

maptk_detect_and_describe
This optional tool pre-computes feature points and descriptors on each frame of video and caches them on disk. The same is also done in the maptk_track_features, so this step is not required. However, this tool makes better use of threading to process all frames in parallel.
maptk_track_featues
Takes a list of images and produces a feature tracks file.
maptk_bundle_adjust_tracks
Takes feature tracks and produces cameras (KRTD files) and 3D points (PLY file). Can also take input POS files or geo-reference points and produce optimized POS files.
maptk_apply_gcp
This tool takes an existing solution from maptk_bundle_adjust_tracks and uses provided ground control points (GCPs) to fit a 3D similarity transformation to align the solution to the GCPs. The same is done in the bundle adjust tool, but this tool lets you update and reapply GCPs without recomputing bundle adjustment.
maptk_pos2krtd
Takes POS files and directly produces KRTD.
maptk_analyze_tracks
Takes images and feature tracks and produces tracking statistics or images with tracks overlaid.
maptk_estimate_homography
Estimates a homography transformation between two images, outputting a file containing the matrices.

Running MAP-Tk Tools

Each MAP-Tk tool has the same interface and accepts three command line arguments:

  • -c to specify an input configuration file
  • -o to output the current configuration to a file
  • -h for help (lists these options)

Each tool has all of its options, including paths to input and output files, specified in the configuration file. To get started, run one of the tools like this:

$ maptk_track_features -o config_file.conf

This will produce an initial set of configuration options. You can then edit config_file.conf to specify input/output files, choices of algorithms, and algorithm parameters. Just as in CMake, configuring some parameters will enable new sub-parameters and you need to re-run the tool to get the updated list of parameters. For example:

$ maptk_track_features -c config_file.conf -o config_file.conf

The above command will overwrite the existing config file with a new file. Ordering of entries and comments are not preserved. Use a different output file name to prevent overwriting the original. Continue to adjust parameters and re-run the above command until the tool no longer reports the message:

ERROR: Configuration not valid.

Note that the config file itself contains detail comments documenting each parameter. For each abstract algorithm you must specify the name of variant to use, but the list of valid names (based on which modules are compiled) is provided directly in the comment for easy reference. When the config file is complete and valid, run the tool one final time as:

$ maptk_track_features -c config_file.conf

An easier way to get started is to use the sample configuration files for each tool that are provided in the examples directory. These examples use recommended default settings that are known to produce useful results on some selected public data samples. The example configuration files include the default configuration files for each algorithm in the config directory.

Getting Help

MAP-Tk is a component of Kitware's collection of open source computer vision tools known as KWIVER. Please join the kwiver-users mailing list to discuss MAP-Tk or to ask for help with using MAP-Tk. For less frequent announcements about MAP-Tk and other KWIVER components, please join the kwiver-announce mailing list.

Acknowledgements

The authors would like to thank AFRL/Sensors Directorate for their support of this work via SBIR Contract FA8650-14-C-1820. This document is approved for public release via 88ABW-2015-2555.