Re: RGBD SLAM and then RGB Localization

Posted by Kaifei on
URL: http://official-rtab-map-forum.206.s1.nabble.com/RGBD-SLAM-and-then-RGB-Localization-tp489p501.html

Thanks! Your code saved me tons of time!

In my case, I need to take RGB images from a smartphone, so I cannot use CameraRGBD.
I can hardcode fx, fy, cx, cy for now.

May I ask two more questions?

1. Why do I need to rectify the image to perform the PnP computation?
In my understanding, image rectification is used to put matched points in two images onto same epipolar lines, so you can find matched points more easily (in one dimension).

PnP is trying to use RANSAC to find the R and t of a camera based on 3D and 2D matched points.
The matched points are calculated based on a series of computation:
    1. project localMap_'s 3D points to previous and current RGB image.
    2. refine the projection using image boundary, 2D point if the word in unique, and optical flow.

However, I don't see which part needs the previous image and current image to be rectified.

2. What is _localTransform in SensorData?
 I think this has confused me a lot while reading the OdometryMono codes.


Thanks again for your quick and detailed answers.
I really really appreciate that!

Bernard