1. Apparatus for lifting a load, the apparatus comprising:
a structure to which the load is mounted; and
means for:
rotating the structure about a first pivot axis so that the load is positioned over an object while remaining mounted to the structure, and
translating the structure towards the pivot axis during the rotation so that the radial distance between the load and the first pivot axis decreases during the rotation.
2. The apparatus of claim 1 wherein the means comprises:
a pair of sleeves spaced in a parallel relation and configured to rotate about the first pivot axis; and
a pair of arms telescopingly engaged with respective ones of the sleeves and connected to the structure;
wherein the first pivot axis passes through the sleeves.
3. The apparatus of claim 2 wherein each arm telescopingly retracts into the corresponding sleeve to effect the translation.
4. The apparatus of claim 3 wherein the structure extends between and is pivotally connected to the distal end portions of the arms; and
wherein the pivot connections between the structure and the distal end portions of the arms define a second pivot axis.
5. The apparatus of claim 4 wherein the structure comprises:
a first rack extending between and pivotally connected to the arms along the second pivot axis; and
a second rack pivotally connected to the first rack along the second pivot axis;
wherein the first rack rotates about the second pivot axis and relative to the arms during the rotation of the structure about the first pivot axis, the first rack rotating until at least a portion of the first rack is substantially coplanar with at least a portion of each arm.
6. The apparatus of claim 5 wherein the load is primarily supported by the first rack prior to the rotation of the structure about the first pivot axis; and
wherein the load is primarily supported by the second rack after the rotation of the structure about the first pivot axis and when the load is positioned over the object.
7. The apparatus of claim 6 wherein the structure has an unloaded configuration in which:
the second rack is positioned over the object; and
the first rack is positioned over the second rack so that the second rack substantially fits within a volumetric envelope defined by the first rack.
8. The apparatus of claim 6 further comprising:
a frame connected to the object;
wherein each sleeve is pivotally connected to the frame; and
wherein the pivot connections between the frame and the sleeves define the first pivot axis.
9. The apparatus of claim 6 wherein the means further comprises:
a winch connected to the object; and
a winch lead line extending from the winch and removably connected to the structure.
10. The apparatus of claim 9 wherein the winch lead line is removably connected to the second rack of the structure.
11. The apparatus of claim 10 wherein the object is an all-terrain vehicle.
12. Apparatus for lifting a load over an object, the apparatus comprising:
a pair of sleeves spaced in a parallel relation wherein corresponding end portions of the sleeves define a first pivot axis;
a pair of arms engaged with respective ones of the sleeves; and
a structure to which the load is mounted, the structure adapted to rotate about the first pivot axis and comprising a first rack extending between and pivotally connected to the arms to define a second pivot axis about which the first rack rotates during the rotation of the structure about the first pivot axis, the first rack rotating until at least a portion of the first rack is substantially coplanar with at least a portion of each arm.
13. The apparatus of claim 12 wherein the structure rotates about the first pivot axis so that the load is positioned over the object while remaining mounted to the structure.
14. The apparatus of claim 13 wherein the arms are telescopingly engaged with the corresponding sleeves; and
wherein the arms telescopingly retract into the corresponding sleeves during the rotation of the structure about the first pivot axis so that the radial distance between the load and the first pivot axis is decreased during the rotation about the first pivot axis.
15. The apparatus of claim 14 wherein the structure further comprises a second rack pivotally connected to the first rack along the second pivot axis.
16. The apparatus of claim 15 wherein the load is primarily supported by the first rack prior to the rotation of the structure about the first pivot axis; and
wherein the load is primarily supported by the second rack after the rotation of the structure about the first pivot axis and when the load is positioned over the object.
17. The apparatus of claim 15 wherein the structure has an unloaded configuration in which:
the second rack is positioned over the object; and
the first rack is positioned over the second rack so that the second rack substantially fits within a volumetric envelope defined by the first rack.
18. The apparatus of claim 12 further comprising:
a winch connected to the object; and
a winch lead line extending from the winch and connected to the structure.
19. A method of lifting a load, the method comprising:
mounting the load to a structure connected to an object;
rotating the structure about a first pivot axis so that the load is positioned over the object while remaining mounted to the structure; and
translating the structure towards the first pivot axis during the rotation so that the radial distance between the load and the pivot axis decreases during the rotation.
20. The method of claim 19 wherein the step of rotating comprises:
pivotally connecting a pair of parallel-spaced arms to the structure;
connecting a winch lead line to the structure; and
retracting the winch lead line so that the arms rotate about the first pivot axis.
21. The method of claim 20 wherein the step of translating comprises:
telescopingly engaging a sleeve with each arm wherein the first pivot axis passes through the sleeves; and
telescopingly retracting the arms into the corresponding sleeves by continuing the step of retracting the winch lead line.
22. The method of claim 21 wherein the pivot connections between the structure and the arms define a second pivot axis; and
further comprising rotating at least a portion of the structure about the second pivot axis and relative to the arms by continuing the step of retracting the winch lead line, the portion of the structure rotating until it is substantially coplanar with at least a portion of each arm.
23. The method of claim 22 wherein the object is an all-terrain vehicle; and
wherein the winch lead line extends from a winch connected to the all-terrain vehicle.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An object activity modeling method comprising the steps of:
(a) obtaining an optical flow vector from a video sequence;
(b) obtaining a probability distribution of a feature vector for a plurality of video frames, using the optical flow vector, wherein the feature vector is an d\xd7L dimensional vector, d being a number of dimensions and L being a number of pixels in a video frame or in a region of interest;
(c) modeling states, using the probability distribution of the feature vector; and
(d) expressing the activity of the object in the video sequence based on state transition.
2. The object activity modeling method of claim 1, wherein the step (a) is based on affine motion estimation.
3. The object activity modeling method of claim 2, wherein the step (a) further comprises the sub-steps of:
(a-1) grouping input video frames into a plurality of video frame groups and dividing each video frame group as an individual state;
(a-2) obtaining an affine motion parameter for each video in the video frame group of each individual state; and
(a-3) obtaining an optical flow vector from the affine motion parameters.
4. The object activity modeling method of claim 3, wherein the step (a-2) comprises a step for determining parameters, which minimizes summed square difference \u03a3(It(x)\u2212It\u22121(x\u2212V(x)))2 over a given video based on the intensity of the pixel on the object, which is expressed as It(x)=It\u22121(x\u2212V(x)) when I denotes intensity, t denotes time, x denotes a pixel location (x, y), and v denotes the motion vector, as motion parameters.
5. The object activity modeling method of claim 1, wherein the step (b) comprises a step for calculating probability distribution P(Z|\u03a9) by the following equation:
P
\u2061
(
Z
\u2758
\u03a9
)
=
exp
\u2061
(
–
1
2
\u2062
(
z
–
m
)
T
)
\u2062
Q
–
1
\u2061
(
Z
–
m
)
)
(
2
\u2062
\u03c0
)
N
\u2062
\uf603
Q
\uf604
1
2
wherein P=(p1,p2, . . . pd) denotes a motion vector calculated at each pixel location (x, y), L denotes the number of pixels in a video frame or a region of interest, d denotes the number of dimensions, feature vector Z, which is a d\xd7L dimension vector, is Z=(p11, p12, . . . , p1L, p21, p22, . . . , p2L, pd1, pd2, . . . pdL)T, m is the mean vector of feature vector Z, and Q is the covariance matrix of feature vector Z, and it is assumed that feature vector Z is provided from observation class \u03a9.
6. The object activity modeling method of claim 1, wherein the step (b) further comprises the steps of:
decomposing covariance matrix Q as the following equation:
Q=\u03a6\u039b\u03a6T
Wherein {circumflex over (Z)} is equal to Z\u2212m, the columns of \u03a6 are orthonormal eigenvectors of covariance matrix Q, and A corresponds to the diagonal eigenvalue; and
calculating probability distribution P(Z|\u03a9) by the following equation:
P
\u2061
(
Z
\u2758
\u03a9
)
=
exp
(
–
1
2
\u2062
\u2211
i
M
\u2062
y
i
2
\u03b1
i
(
2
\u2062
\u03c0
)
M
\u2062
\uf603
\u039b
\uf604
1
2
exp
\u2061
(
–
1
2
\u2062
\u2211
M
+
1
N
\u2062
y
i
2
2
\u2062
\u03c1
)
i
(
2
\u2062
\u03c0\u03c1
)
(
N
–
M
)
2
wherein M is the number of principal components, yi is the i-th component of Y, \u03b1i is the i-th eigenvalue of Q, and \u03c1 is the optimal value, which is obtained by
\u03c1
=
1
N
–
M
\u2062
\u2211
M
+
1
N
\u2062
\u03b1
i
,
and it is assumed that feature vector Z is provided from observation class \u03a9.
7. The object activity modeling method of claim 1, wherein in the step (c), the object activity in the video sequence is expressed using a Hidden Markov Model (HMM), based on state transition.
8. The object activity modeling method of claim 7, wherein the Hidden Markov Model (HMM) is expressed as \u03bb={\u039e, A, B, \u03a0} when N is the number of possible states, \u039e satisfies \u039e={q1, q2, . . . , qN}, A is {aij}, the transition between hidden states i and j, B is {bj(.)}, the observation symbol probability corresponding to state j, and \u03a0 is the initial state distribution, and the state \u039e={q1, q2, . . . , qN} and the initial state distribution \u03a0 are determined in advance based on video data.