C
Measurements within reference plane
Solve for homography H relating reference plane to image plane
•H maps
reference plane (X,Y) coords to image plane (x,y) coords
•Fully determined from 4 known points on ground
plane
–Option A: physically measure 4 points on ground
–Option B: find a square, guess the dimensions
–Option
C: Note
H = columns 1,2,4 projection matrix
»derive on board
•Given (x, y), can find
(X,Y) by H-1
reference plane
image plane