Visual Map Construction Using RGB-D Sensors for Image-Based Localization in Indoor Environments

Algorithm 2

Global optimization based on the RGB-D loop closure detection and the g2o algorithm.

(1) Select the keyframes by the fixed-distance strategy;

(2) Select the keyframes by the matching-ratio strategy;

(3) Obtain the keyframe set by ;

(4) Set the total number of the keyframe set ;

(5) while  

(6)Match the current keyframe with the previous

keyframes ;

(7)Compute the depth errors of the pixel patches in the

current keyframe and the previous keyframes ;

(8)if   and

(9)Perform the g2o algorithm with the camera pose ;

(10)break;

(11)end

(12);

(13) end