Table 2 15 images were annotated by 10 users to obtain a covariance matrix per key point per image. The average covariance matrix for a single key point is obtained by finding the mean and standard deviation of the 15 covariance matrix

a

b

\(\left (\begin {array}{cc} 9.06 \pm 6.37 & -0.127 \pm 2.64 \\ -0.127 \pm 2.64 & 6.20 \pm 3.99 \end {array}\right)\)

\(\left (\begin {array}{cc} 16.3 \pm 13.1 & 5.22 \pm 4.19 \\ 5.22 \pm 4.19 & 5.17 \pm 2.20 \end {array}\right)\)

c

d

\(\left (\begin {array}{cc} 12.1 \pm 14.2 & -2.50 \pm 3.73 \\ -2.50 \pm 3.73 & 2.75 \pm 2.07 \end {array}\right)\)

\({\left (\begin {array}{cc} 2.47 \pm 1.33 & -0.0481 \pm 0.584 \\ -0.0481 \pm 0.584 & 1.40 \pm 0.836 \end {array}\right)}\)

e

f

\(\left (\begin {array}{cc} 1.99 \pm 0.935 & 0.0319 \pm 0.655 \\ 0.0319 \pm 0.655 & 2.07 \pm 0.927 \end {array}\right)\)

\({\left (\begin {array}{cc} 1.72 \pm 1.17 & -0.0474 \pm 0.452 \\ -0.0474 \pm 0.452 & 1.38 \pm 0.652 \end {array}\right)}\)

g

h

\(\left (\begin {array}{cc} 2.35 \pm 1.48 & 0.263 \pm 0.840 \\ 0.263 \pm 0.840 & 2.21 \pm 1.62 \end {array}\right)\)

\(\left (\begin {array}{cc} 2.43 \pm 1.32 & 0.259 \pm 0.980 \\ 0.259 \pm 0.980 & 2.06 \pm 1.45 \end {array}\right)\)

i

j

\(\left (\begin {array}{cc} 2.22 \pm 1.32 & -0.141 \pm 0.710 \\ -0.141 \pm 0.710 & 1.35 \pm 0.633 \end {array}\right)\)

\(\left (\begin {array}{cc} 2.41 \pm 0.848 & 0.190 \pm 0.691 \\ 0.190 \pm 0.691 & 1.81 \pm 0.669 \end {array}\right)\)

k

l

\(\left (\begin {array}{cc} 12.3 \pm 9.36 & 6.16 \pm 6.01 \\ 6.16 \pm 6.01 & 8.91 \pm 5.29 \end {array}\right)\)

\(\left (\begin {array}{cc} 5.21 \pm 2.62 & -1.43 \pm 1.26 \\ -1.43 \pm 1.26 & 1.97 \pm 0.746 \end {array}\right)\)

m

\(\left (\begin {array}{cc} 13.5 \pm 15.0 & -3.64 \pm 5.56 \\ -3.64 \pm 5.56 & 9.09 \pm 5.76 \end {array}\right)\)