1. A screw for fixing vertebra comprising:
a screw body having a screw portion driven into and fixed to the vertebra and a spherical head portion formed at the top end of the screw portion;
a movable washer, which includes a head seat portion formed therein so that the head portion of the screw body is mounted thereon after the screw portion of the screw body is inserted therein, and in which the screw body is pivotally joined therein in sliding contact between the head portion and the head seat portion;
a fastening nut which includes an insertion hole formed therein to insert and pass the screw body, a washer seat portion formed below the insertion hole so that the movable washer is pivotally mounted thereon in sliding contact between the movable washer and the washer seat portion, and a rod fastening groove which extends from the upper side of the washer seat portion to the top end of the fastening nut; and
a clamping bolt which includes a male thread formed thereon to be screwed into an upper portion of the insertion hole of the fastening nut, so as to press and fix a connecting rod inserted through the rod fastening groove of the fastening nut.
2. The screw according to claim 1, wherein the fastening nut includes a first aperture formed with a sloping face whose width gradually widens as it goes downward from the lower portion of the washer seat portion, and
a bottom end portion of the head seat portion of the movable washer is protruded out of the fastening nut through the first aperture of the fastening nut.
3. The screw according to claim 2, wherein a height of the bottom end portion of the movable washer exposed downward of the fastening nut through the first aperture is equal to the height of the first aperture.
4. The screw according to claim 3, wherein the movable washer has a second aperture formed with a sloping face whose width widens gradually as it goes downward from the lower portion of the head seat portion.
5. The screw according to claim 4, wherein the screw portion of the screw body includes a thread formed thereon from the bottom end thereof, and
an elongating portion which elongates between the thread and the head portion and does not have a thread formed thereon.
6. The screw according to claim 5, wherein a first tool insert groove for inserting a tool is formed in the top end portion of the head portion of the screw body, and
a shaking prevention groove communicating with the first tool insert groove is formed at the center of the head portion of the screw body.
7. The screw according to claim 5, wherein a length of the elongating portion is equal to the sum of a length of the sloping face of the first aperture of the fastening nut and a length of the sloping face of the second aperture of the movable washer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-9. (canceled)
10. A method for tracking at least one object in a scene, comprising:
detecting, by means of an image detector, a sequence of images of the scene;
determining a movement of at least one object in the scene based on the sequence of images;
starting a counter when the movement of the at least one object comes to a standstill; and
generating a signal when a counter value reaches a predetermined threshold value.
11. The method as recited in claim 1, wherein the signal triggers at least one of an audio alarm and visual alarm.
12. The method as recited in claim 1, further comprising:
generating a list describing the movement of the at least one object with respect to the direction of movement and the time.
13. The method as recited in claim 12, wherein the list is newly initialized after the beginning of a movement of the at least one object.
14. The method as recited in claim 12, further comprising:
generating a reference image, wherein the reference image is used to identify the at least one object in the scene.
15. The method as recited in claim 14, wherein, after identifying the position of the at least one object, the reference image is adapted onto remaining areas of the scene from at least one preceding image.
16. The method as recited in claim 14, wherein a time interval of at least half a second is provided between images.
17. A video monitoring system for tracking at least one object in a scene, comprising:
at least one image detector for detecting a sequence of images of the scene;
a processor connected to the image detector for determining a movement of at least one object in the scene based on the sequence of images, wherein the processor starts a time count when the movement of the at least one object comes to a standstill; and
an output arrangement connected to the processor for generating a signal when the time count value reaches a predetermined threshold value.
18. The system as recited in claim 17, wherein the processor generates a list describing the movement of the at least one object with respect to the direction of movement and the time.
19. The system as recited in claim 18, wherein the list is newly initialized after the beginning of a movement of the at least one object.
20. The system as recited in claim 18, wherein a reference image generated, the reference image being used to identify the at least one object in the scene.