daniilidis-group/event_feature_tracking

This repo contains MATLAB implementations of the event-based feature tracking methods described in "Event-based Feature Tracking with Probabilistic Data Association" and "Event-based Visual Inertial Odometry".

event_feature_tracking's Issues

Question about tracking process time

Hi, I would like to know how much time would one tracking iteration commonly take?

I thought it would be a real-time implementation but one iteration takes a few seconds on my personal laptop as is shown in the attached picture. I don't know where the problem is and how to run it in real time. The used dataset is the "shapes_6dof" from rpg's event camera datasets.

Thank you for your help.

what's the function 'sub2indc' in generate_undistort_map_radtan.m??

I have some questions about em1 and em2.

My first confuse is:
This system defines two templates 'ef.prev_shifted_weights' and 'ef.template_decimated'? Can em1 use 'ef.template_decimated' as a template?

My second confuse is:
In the em2_affine.m,Line 230:
time_shifted_points = bsxfun(@minus, events(1:2, :), ...
feature_pos + flow * dt) + ...
bsxfun(@times, flow, (events(3, end) - events(3, :)));
In order to calculate 'time_shifted_points', Can this use the new feature point position and the new optical flow after the affine warping?

Question about 'multi vehicle stereo event camera' dataset

Hi,
First of all, thank you so much for sharing the great dataset :)
But I have a question about it.
I'm not sure is this the right place to ask, however, the dataset project page sent me here. I'm sorry if I was wrong.

I downloaded the hdf5 version of the dataset, and I want to know what '/davis/left/imu' columns point to.
I guess they would be [ax(m/s^2), ay, az, rx(rad/s), ry, rz], but I'm not sure. I can't find out in project site or papers. And what Hz is davis/imu data?

Thanks!

several issues regarding data pre-processing

Hi Alex,

Thanks for sharing the code!

I have found the following problem while I was trying to run the code with "Event Camera Dataset(boxes_6dof.bag)".

1. topic name: extract_ros_data.m
   davis -> dvs
   My event cam(240C) as well.

2. large file store: extract_ros_data.m
   '-v7.3' option is missing for a large file save
   save(output_name,'file_name','events',...
   'lin_acc','ang_vel','imu_time', 'cinfo','-v7.3' );
   It could be problem of 2016b and under.

3. undistort problem: generate_undistort_map_radtan.m
   error message:

Error using ones
Requested 86400x86400 (55.6GB) array exceeds maximum array size preference. Creation of arrays greater than this limit may take a long time and cause MATLAB to become unresponsive. See array size limit or preference panel for
more information.

Error in lsqncommon (line 148)
            Jstr = sparse(ones(Jrows,Jcols));

Error in lsqcurvefit (line 257)
    lsqncommon(funfcn,xCurrent,lb,ub,options,defaultopt,caller,...

Error in lscftsh

Error in cameraParameters/undistortPointsImpl (line 221)
                lscftsh(@this.distortPoints, points, [], points, [], [], options);

Error in undistortPoints (line 91)
undistortedPointsDouble = undistortPointsImpl(cameraParams, pointsDouble);

Which matlab version is utilized for the code?
I am currently using 2016b. If you did not have the same problems above, it might be the version problem. I could not solve the last problem. Matlab's simple example code (undistortPoints) works well but not with the "boxes_6dof" (42k points). Still did not get why it needs that much of matrix.

Added -> I found another post related to this problem. Maybe I need to get the software update.
https://au.mathworks.com/matlabcentral/answers/297569-memory-issue-with-undistortpoints

Error using vertcat Out of memory. Type HELP MEMORY for your options.

When I run main.m using boxes_6dof I met this problem.
`
Error using vertcat
Out of memory. Type HELP MEMORY for your options.

Error in undistort_events (line 53)
undistorted_events = [x_u; y_u; events(3:4, valid_points)];

Error in main (line 57)
events_zeroed = undistort_events(...
`
My machine : 8GiB memory and 10GiB Swap space. I want to know if there is something wrong when I run the code or this project need more memory.

Where is the camera pose ? trackers?

Hi,
I have ran your code successfully, but after that where can I get the 6dof camera pose? I want to make figure 5 of your paper 'Event-based Visual Inertial Odometry', what should I do?
Thanks very much!