Detecting target movement
First Claim
1. Apparatus for determining the speed of an object moving relative to a scene comprising:
- means (20, 21,
22) for providing a plurality of frames of data representing successive images of at least a portion of the scene, each frame comprising an object segment, in which features of the object predominate, and at least one background segment comprising part of the frame excluding the object segment;
means (23;
8.3) for effecting registration of features in a background segment of one of said plurality of frames with corresponding features in a background segment of a reference frame comprising a different one of said plurality of frames;
means (23;
8.5, 8.7) for determining displacement of features in said object segment of said one of said plurality of frames relative to the registered background segment features; and
means (23;
8.14) for computing from the displacement of the object features over a predetermined number of frames, the speed of movement of the object relative to the background features.
2 Assignments
0 Petitions
Accused Products
Abstract
In apparatus, such as a weapon sight, the speed of an object moving relative to a scene is determined by processing a plurality of successive frames of data, each obtained by scanning the scene, and detecting motion of the object relative to the background/foreground features of the scene. Each frame is compared with a reference comprising a different one of the frames and corresponding background features registered. Once the frames are registered, light intensity values of corresponding elements of the frames are subtracted. The registered background features, being stationary, cancel leaving the object features. Displacement of the object features over a predetermined number of frames is used to calculate the crossing speed of the object relative to the background features.
107 Citations
48 Claims
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1. Apparatus for determining the speed of an object moving relative to a scene comprising:
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means (20, 21,
22) for providing a plurality of frames of data representing successive images of at least a portion of the scene, each frame comprising an object segment, in which features of the object predominate, and at least one background segment comprising part of the frame excluding the object segment;means (23;
8.3) for effecting registration of features in a background segment of one of said plurality of frames with corresponding features in a background segment of a reference frame comprising a different one of said plurality of frames;means (23;
8.5, 8.7) for determining displacement of features in said object segment of said one of said plurality of frames relative to the registered background segment features; andmeans (23;
8.14) for computing from the displacement of the object features over a predetermined number of frames, the speed of movement of the object relative to the background features. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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2. Apparatus as claimed in claim wherein said registration effecting means includes means (8.1, 8.4, 8.6) for initially selecting a first of said plurality of frames as said reference frame and, when a subsequent frame has been registered successfully, substituting such subsequent frame as said reference frame for use in registering succeeding frames.
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26. A method of determining the speed of an object moving relative to a scene comprising the steps of:
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providing a plurality of frames of data representing successive images of at least a portion of the scene, each frame comprising an object segment, in which features of the object predominate, and a background segment comprising parts of the frame excluding the object segment and in which features of the object do not predominate; effecting registration (8.3) of features in a background segment of one of said plurality of frames with corresponding features in a background segment of a reference frame comprising a different one of said plurality of frames; determining displacement (8.5, 8.7) of features in said object segment of said one of said plurality of frames relative to the registered background segment features; and computing (8.14), from the displacement of the object features over a predetermined number of frames, the speed of movement of the object relative to the background features. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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Specification