PR2: Adding ColorUtils namespace with functions to replace cv::viz::color calls in non-visualizer classes.

[sarika93]

This is the second PR in a series of changes that aim to make building with the visualizer module optional and remove the cv::viz dependency from other modules. A number of different non-visualization classes include cv::viz, which we would like to optionally remove when building without visualization. In the majority of these cases, this is only to get cv::viz::Color values.

This PR adds a new ColorUtils namespace with inline Color related functions that can be used instead of cv::viz::Color functions in non-visualizer classes. Non-visualizer classes are updated to remove the cv::viz-related includes and make use of these new functions. Things to note:

• In testTracker.cpp and testOpticalFlowPredictor.cpp the cv::viz::Color calls are not updated because those are part of larger cv::viz-dependent blocks that need to be handled differently (e.g. using #ifdef blocks to exclude that logic).
• Color functions are only included for those colors that are required outside of visualizer classes.

Full design document:
Visualization Build Option Refactor for Kimera-VIO.pdf

Testing process
Build docker container for testing

• Navigate to Kimera-VIO/scripts/Docker
• Modify the Dockerfile to get the relevant testing branch instead of master. Change line 85 to the following:

RUN git clone https://github.com/Virtana/Kimera-VIO.git && git checkout origin/<branch_name>

• Build and run the image:

./kimera_vio_docker.bash

Testing

1. Update Kimera-VIO to generate logs:
   1. For stereo: Open Kimera-VIO/params/Euroc/flags/stereoVIOEuroc.flags with your editor of choice and modify -- log_output to true.
   2. For mono:
      1. Open Kimera-VIO/params/EurocMono/flags/stereoVIOEuroc.flags and modify -- log_output to true.
      2. Open Kimera-VIO/params/EurocMono/BackendParams.yaml with the following changes:
         • linearizationMode: 1
      3. Open Kimera-VIO/params/EurocMono/FrontendParams.yaml with the following changes:
         • maxFeatureAge: 15
         • feature_detector_type: 0
         • maxFeaturesPerFrame: 200
      4. Open Kimera-VIO/script/stereoVIOEuroc.bash and change the LOG_OUTPUT variable from 0 to 1.
2. Run Kimera-VIO: ./stereoVIOEuroc.bash.
3. You can examine output logs in Kimera-VIO/output_logs/ to ensure the values in traj_gt.csv are the same as the version on master. You can re-run after checking out to master and rebuilding and installing:

git checkout master
rm -r build && mkdir build
cd build
cmake .. && make -j4 install

Then re-run Kimera-VIO as shown in step 2. You should be re-running with the same configuration options.

You should also be looking out for any differences in the visualizer behaviour.