Vision odometry is the use of image processing to determine and estimate the movement of the rovers.
Angular motion measures how far the rover turns. The process captures an image and as the rover turns the image shifts. The number of pixels in the shifted image determines how much the rover has turned.
This note captures the calculations on how many pixels the image needs to shift to do a specific turn.
The web camera used has a 75 degree field of vision. The image size I have settled on is 424 x 240 pixels. Therefore:
424 px / 75 deg = 5.7 px / deg
75 deg / 424 px = 0.177 deg / px
At times in the competition the camera is panned to locate and determine the bearing to landmarks. The sail winch servo used does a 360 deg scan when the control signal changes by 1200 msecs. Therefore:
360 deg / 1200 msec = 0.3 deg / msec
1200 msec / 360 deg = 3.33 msec / deg