Method and system for controlling camera through wireless sensor network
A method for controlling a camera through a Multi-Hop-based wireless sensor network includes: sensing whether an event occurs or not in a corresponding area and transmitting position information on the corresponding area and type information on the event, converting the received position information on the event into a movement control signal for the camera, calculating camera driving values in a left/right direction and an up/down direction using the converted signal, controlling a zoom-in operation of the camera lens using the calculated camera driving values according to the received event type and photographing an object located in the corresponding direction, and transmitting the photographed images over the outer network.
1. A method for controlling a camera through a Multi-Hop-based wireless sensor network, comprising:
receiving, at the camera, an indication of an event related to a movement of an object from a sensor node in the Multi-Hop-based wireless sensor network, wherein the indication indicates a position information of the event and a type of the event, and wherein the event is detected by the sensor node based on a difference between a movement vector of the object at a current sensor and a movement vector of the object at a previous sensor;
controlling a zoom-in operation of a lens of the camera according to the type of the event;
capturing an image based on a movement control signal that causes the camera to move in at least one direction, wherein the movement control signal is generated by using the position information; and
transmitting the captured image over a communications network.
2. The method according to claim 1 , further comprising
generating the movement control signal based on the position information, the generating comprising:
calculating movement angles between a camera direction and a direction from a current position of the camera to an event occurrence position; and
calculating a number of pulses using the calculated movement angles.
3. The method according to claim 2 , wherein the movement angles are calculated by:
Movement
Angle
=
cos
-
1
(
sw
_
2
+
sr
_
2
-
rw
_
2
2
·
sw
_
·
sr
_
)
,
wherein s represents the camera direction, w represents the current position of the camera, and r represents the event occurrence position.
4. The method according to claim 2 , wherein the number of pulses is calculated by:
Movement
Angle
Step
Angle
×
Y
=
Actual
Pulse
Number
of
Motor
wherein a gear ratio of a motor of the camera is 1/Y.
5. The method according to claim 1 , wherein the type of the event is one of a situational event type and a movement event type.
6. The method according to claim 1 , wherein a zoom of the lens of the camera is selectively changed to a level corresponding to the type of the event.
7. A system for controlling a camera through a Multi-Hop-based wireless sensor network, comprising:
a wireless sensor network having a plurality of sensor nodes, wherein each sensor node is operable to sense: whether specified events that are associated with a movement of an object occur or not, positions associated with the movement of the object, and types of the specified events, wherein each of the specified events is sensed based on a difference between a movement vector of the object sensed at a current sensor and a movement vector of the object sensed at a previous sensor being greater than a preset threshold;
a camera device for receiving, from any of the plurality of sensor nodes, an indication that an event associated with the movement of the object has occurred, wherein the indication includes a position information of the event and a type of the event, converting the position information into a control signal, and performing a movement control according to the control signal; and
a controller server for storing images captured by the camera device and transmitting the images over a network.
8. The system according to claim 7 , wherein the camera device comprises:
a Global Positioning System (GPS) receiving unit for identifying a current position of the camera device;
a control signal conversion unit for converting the position information into the control signal;
a movement control unit for controlling movement of the camera device and a zoom of a lens of the camera device based on the control signal; and
a camera driving unit for causing the camera device to capture an image.
9. The system according to claim 8 , wherein the movement control unit comprises:
a tilt control unit for controlling up/down movement of the camera device according to a calculated number of pulses; and
a pan control unit for controlling left/right movement of the camera device according to the calculated number of pulses.
10. The system according to claim 9 , wherein the control signal conversion unit generates the control signal
by using a movement angle between a camera direction and a direction from a current position of the camera to a corresponding event occurrence position by:
Movement
Angle
=
cos
-
1
(
sw
_
2
+
sr
_
2
-
rw
_
2
2
·
sw
_
·
sr
_
)
wherein s represents the camera direction, w represents the current position of the camera, and r represents the event occurrence position, and
wherein the number of pulses is obtained by using the movement angle by:
Movement
Angle
Step
Angle
×
Y
=
Actual
Pulse
Number
of
Motor
wherein a gear ratio of a motor of the camera device is 1/Y.
11. The system according to claim 8 , wherein the camera device further comprises a communications interface for receiving information transmitted by any of the sensor nodes.
12. The system according to claim 8 , wherein the zoom of the lens of the camera device is selectively changed to a level corresponding to the type of the event.
13. The system according to claim 7 , further comprising an interface device for providing an interface between the wireless sensor network and the camera device.
14. The system according to claim 7 , wherein the type of the event includes at least one of a movement event type and an intrusion event type.