live_slam and dataset_slam is not working about lsd_slam

[JakobEngel]

hmm, can you upload the images somewhere so I can have a look at them?

[jferdelyi]

I would be more than happy to do so, but unfortunately the images I'm using are not my property and so I don't have the right to publish them.
We managed to use the calibration by directly entering the D, K, R, P matrixes in the ROS node that publishes the video.
However, when we tried to implement all this on the drone, we encoutered a problem with a dimension that you cannot multiply by 16 which makes us use the .cfg with the crop mode file but the algorithm wouldn't work correctly.

[JakobEngel]

hmm, the multiple-of-16 constraint is somewhat unfortunate anyway, and could be changed with some work. How do you crop the image? If you just crop of pixels on the right / bottom (no re-scaling, no cropping on top / left), the calibration parameters fx, fy, cx, cy stay the same. however as the parameters from the calibration file fromat used by LSD-SLAM are scaled with width and height, they have to be changed respectively. (i.e. multiply fx and cx with (oldWidth/newWidth), and the same with fy and cy).

[QichaoXu]

@mhkabir, Hello,

I'm working on ROS indigo + ubuntu 14.04 LTS,
I have got results using dataset_slam, but the results seems not so good.

I use a monochrome global-shutter camera (exactly the same as the one you recommend in the homepage),

1. but I don't know how to use live_slam with this camera.
   I mean, there should be some commands to initiate it, how? Could you tell me the details?
2. more, could you tell me how you calibrate your camera? Because my calibration seems
   not efficient, which may be the reason why dataset_slam result is bad.

I think using the recommended camera could make things easy, as you have all worked with it successfully.

[JakobEngel]

@QichaoXu

• for calibrating the camera I always used the PTAM cameracalibrator, e.g. from here: https://github.com/JakobEngel/ethzasl_ptam (fork from ETH's ROS-PTAM port), which works very well.
• during live-usage, simply press 'r' to reset everything, and then slowly move the camera sideways (do not rotate it!), for initialization. Also, best start with a fixed exposure value, as aggressive auto-shutter corrections may cause problems sometimes.

[QichaoXu]

@JakobEngel ,thank you for your reply. I'm working on it.

[karim-nemra]

Hello

I am new in ROS,

I am using the LSD-SLAM, for live test I am using *.bag file, is it possible to use an *.avi video as input.

Does the *.bag file contain only the images?

Thank you very much for your answe

[karim-nemra]

Hello, Jakob Engel

I have the following message, after few munites. The same message with different squences

warning: reciprocal tracking on new frame failed badly, added odometry edge (Hacky).
terminate called after throwing an instance of 'Sophus::ScaleNotPositive'
what(): Sophus exception: Scale factor is not positive
Aborted (core dumped)

[QichaoXu]

@JakobEngel

The results of live_slam running on my computer are always not so good, what could be the problem probably?

I thought there could be these two reasons?

1.My calibration file is:
1.1977124 1.1977124 0.49921875 0.498958333 0
640 480
1.1977124 1.1977124 0.49921875 0.498958333 0
640 480
could there any wrong in my calibration?

2.I have always wanna ask, could the processing speed of the computer have any bad influence on the result? If processing speed isn't fast enough to calculate information in each frame, could it effect the result?

What do you think? Hope you can give me some suggestions.

[liqile]

@QichaoXu hi, have you solved your problem? I faced with similar problem.
how to run lsd with your own data?

中文翻译：您好，请问您的问题现在解决了吗，我现在不知道如何跑其他的数据。我现在想用lsd跑一下tum上rgb-d的其他数据，但是viewer总是啥都不显示

[giancan]

@JakobEngel Hi, are there any news on this topic? I get the same error and I would like to process some images extracted from a video. Should I change anything? Will it make any difference if I scale the images down and recalibrate the camera?
Thanks