Visual Features
We currently implement visual features for RGB-depth images (RGB-D) as captured by the Microsoft Kinect or the Asus Xtion PRO LIVE.
For a given query pixel q, the image feature response is calculated as the difference of two rectangular offset regions on the image channel in the neighborhood around the query pixel.
Extent size w_i, h_i and relative offset o_i of the rectangular region in the image is normalized by the depth at the query pixel. This leads to the effect that the feature gets smaller if applied on pixels that have a larger distance (eg. background pixels).
We implement the two feature types
-
color, -
depth.
Color features use only color channels to calculate the sum of the rectangular region while the two regions can be calculated on two different color channels.
Depth features use only the depth channel of the image.