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kknaur
Posts: 540
Posted 13:43 May 30, 2011 |

[x1, y1] = x y location of the upper left corner of the macro block


[x2, y2] = x y location of the upper left corner of the best matched block in the reference image


Is the motion vector calculated by:

mv = [x1 - x2, y1 - y2]


OR


mv = [x2 - x1, y2 - y1]


Thank you

Last edited by kknaur at 16:10 May 31, 2011.
cbort
Posts: 95
Posted 15:58 May 30, 2011 |

um generally I think the norm is

difference = final - initial, so

x2-x1

so if x2 > x1 it is moving in the positive direction and if x2 < x1 its negative motion...

although as long as you keep the same thing I dont think it matters... she took down her example so I cant really say what she did...

cbort
Posts: 95
Posted 16:03 May 30, 2011 |

so ya what I just said

http://www.calstatela.edu/faculty/eykang/courses/cs451/Lec10-VideoCompressionBasic.pdf

Pg 4

the bottom slide...

d = (dx, dy) = (x, y)–(x’, y’) assuming that cn+1(x , y) is same or very similar to cn(x’ , y’)

or following yours

x2 - x1