dvo_python: Dense visual odometry in Python(3.6(.6))

Coded up in slightly longer than a night! :)

Someone tweeted about this elegant implementation , and that's what made my day (rather, my night). I was like, "Hmm, a good refresher on dense SLAM would be to implement this, let me do it in Python."

The first coding sprint ran for about 7.5 hours, in which I implemented most of the framework, i.e., the residual and Jacobian computation, and a simplish gradient-descent optimizer.

Micromanagement

• [x] Work out dependencies (numpy, OpenCV, some SE(3) package(??), matplotlib)
• [x] Read in a pair of pointclouds and visualize them
• [x] Construct image and depth pyramids
• [x] Compute the residual (warping error)
• [x] Implement SE(3) routines
• [x] Implement image gradient computation
• [x] Compute Jacobian of the error function
• [x] Write a Gradient-descent optimizer
• [ ] Write a Gauss-Newton optimizer
• [ ] Robustify the error function (IRLS / M-Estimators)
• [ ] Debug the two-image alignment case
• [ ] Extend to a sequence of several images
• [ ] Setup class to load a TUM RGB-D sequence and run dvo _python on it.
• [ ] Debug!
• [ ] Check for any possibile visualization glitches/enhancements.

Big picture checklist

• [x] Barebones version of repo up
• [x] Chalk out repo structure, order in which to code
• [x] Put the order up as a checklist
• [ ] Code & Debug (on a pair of images)!
• [ ] Code & Debug on a sequence of images
• [ ] Get it to run on TUM RGB-D!
• [ ] Benchmark (time and accuracy)
• [ ] Finish up documentation and README
• [ ] Take a moment to revel in a sense of accomplishment ;)
• [ ] Get some sleep!!! :)

Activity Log

Times are in 24-hour format.

Night 1: 21 November-22 November 2018

• 2000 - 2020: Chalk out action plan.
• 2020 - 2050: Dinner break.
• 2100 - 2130: Download a sequence from TUM RGB-D, load and display stuff
• 2140 - 2300: Build pyramid levels (plus a lot of interruptions :|)
• 2330 - 0115: Compute the photometric warp error
• 0115 - 0145: Get SE(3) helper functions in
• 0200 - 0220: Image gradient computation, fetch SE(3) Jacobian helper functions
• 0220 - 0310: Implement Jacobian computation
• 0310 - 0330: Implement gradient descent optimizer

Day 2: 22 November 2018

• 1100 - 1130: Vectorize image pyramid level construction
• 1614 - 1645: Vectorize edge-preserving depth pyramid level construction