MONITORING SYSTEM, CAMERA, AND VIDEO ENCODING METHOD

• US 20100097470A1
• Filed: 09/20/2007
• Published: 04/22/2010
• Est. Priority Date: 09/20/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yamaguchi, Takao, Yoshida, Atsushi, Aoki, Katsuji
• Granted Patent: US 8,115,812 B2
• Time in Patent Office: Days
• US Class Current: 348/159
• CPC Class Codes: G08B 13/19641 Multiple cameras having overlapping views on a single scene
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 23/631 Graphical user interfaces [GUI] specially adapted for controlling image capture or setting capture parameters
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/661 Transmitting camera control signals through networks, e.g. control via the Internet
• CPC Class Codes: H04N 23/695 Control of camera direction for changing a field of view, e.g. pan, tilt or based on tracking of objects
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A monitor system is provided for making it possible to efficiently determine a coding quantity of each camera in accordance with the movement of an object. In each camera (101) composing the monitor system, based on a position of the object detected by a sensor (106) and position specifying information of neighboring cameras and cooperation parameters stored at a neighboring camera information memory unit (405), (1) a distribution pattern indicative of a distribution of values of the cooperation parameter in a space where a plurality of the cameras exist forms a concentric circle defined from the object as a starting point, and (2) a cooperation parameter renewal unit (413) for renewing the cooperation parameters so that a target coding quantity of the camera, which picks up an image of the object, can be larger than a target quantity of the camera, which has not picked up an image of the object, and the camera is provided with a target coding quantity determining unit (410) for determining the target coding quantity allocated to its own camera based on the cooperation parameters of the neighboring camera and the target coding quantity stored at the neighboring camera information memory unit (405).

Claims

1. A monitoring system comprising plural cameras connected through a transmission path,

wherein each of said plural cameras includes:

an object detecting unit operable to detect an object that is a moving object to be monitored;

a video capturing unit operable to capture the object detected by said object detecting unit so as to obtain video;

a video encoding unit operable to encode the video obtained by said capturing unit;

a collaboration parameter storage unit for storing a collaboration parameter indicating a relative amount of a target code amount assigned to a camera and a target code amount assigned to a neighboring camera, the target code amount being a target value for video encoding, and said neighboring camera being a predetermined camera, among said plural cameras, that is located near said camera;

a communication interface unit operable to exchange, by communicating with said neighboring camera, the collaboration parameter stored in said collaboration parameter storage unit of said camera and the target code amount assigned to said camera;

a neighboring camera information storage unit for storing position identification information for identifying a position of said neighboring camera, as well as the collaboration parameter and the target code amount for said neighboring camera that are obtained by said communication interface unit;

a collaboration parameter updating unit operable to update the collaboration parameter stored in said collaboration parameter storage unit, based on a position of the object detected by said object detecting unit as well as the position identification information and the collaboration parameter of said neighboring camera that are stored in said neighboring camera information storage unit, so that (i) a distribution pattern, which indicates a distribution of a value of the collaboration parameter in a space in which said plural cameras are present, forms concentric circles having the object detected by said object detecting unit as an origin, and that (ii) the target code amount for a camera capturing the object becomes larger than the target code amount for a camera not capturing the object; and

a target code amount determining unit operable to determine the target code amount to be assigned to said camera, based on the collaboration parameter updated by said collaboration parameter updating unit as well as the collaboration parameter and the target code amount for said neighboring camera that are stored in said neighboring camera information storage unit, and

wherein said video encoding unit is operable to encode the video so that an amount of code generated in the encoding attains the target code amount determined by said target code amount determining unit.

2. The monitoring system according to claim 1,

wherein said target code amount determining unit is operable to specify a curvature of an arc in a region in which said camera is present, in the distribution pattern of the collaboration parameter updated by said collaboration parameter updating unit, and to determine the target code amount so that the target code amount becomes larger as the specified curvature becomes larger.

3. The monitoring system according to claim 2,

wherein said target code amount determining unit, which holds a template that is information defining distances each corresponding to one of plural curvatures of arcs of the distribution pattern, is operable to specify, by referring to the template, a distance according to the curvature of the arc of the region in which said camera is present, and to determine the target code amount so that the target code amount becomes larger as the specified distance becomes smaller, each of the distances being a distance from a corresponding arc to the object.

4. The monitoring system according to claim 1,

wherein said collaboration parameter updating unit is operable to update the collaboration parameter so as to form a distribution pattern of regions having a large collaboration parameter and regions having a small collaboration parameter which are alternately formed, the regions being concentric and having the object as an origin.

5. The monitoring system according to claim 4,

wherein said object detecting unit is operable to detect a moving direction of the object, and

said collaboration parameter updating unit is operable to update the collaboration parameter so as to form a distribution pattern in which intervals at which the regions having the large collaboration parameter and the regions having the small collaboration parameter alternate become larger towards the moving direction of the object.

6. monitoring system according to claim 5,

wherein said object detecting unit further detects a moving speed of the object, and

said collaboration parameter updating unit is operable to update the collaboration parameter so as to form a distribution pattern in which the intervals at which the regions having the large collaboration parameter and the regions having the small collaboration parameter alternate become larger as the moving speed of the object becomes larger.

7. The monitoring system according to claim 1,

wherein said collaboration parameter updating unit is operable to update the collaboration parameter so that an amount of increase or decrease of the collaboration parameter is in accordance with a reaction-diffusion equation, the amount of increase or decrease being dependent on sensor information which indicates at least one of a presence or absence, a moving speed, and a moving direction of the object.

8. The monitoring system according to claim 7,

wherein in the reaction-diffusion equation, the increase or decrease of the collaboration parameter is represented by a sum of a reaction term and a diffusion term, and

said collaboration parameter updating unit includes:

an autonomous operation executing unit operable to update the collaboration parameter so that the collaboration parameter increases or decreases in accordance with the reaction term and

a collaboration operation executing unit operable to update the collaboration parameter so that the collaboration parameter increases or decreases in accordance with the diffusion term.

9. The monitoring system according to claim 1,

wherein said communication interface unit is further operable to output, via the transmission path, the video encoded by said video encoding unit, and

said target code amount determining unit is operable to determine a provisional target code amount by substituting a predetermined function with the collaboration parameter updated by said collaboration parameter updating unit as well as the collaboration parameter and the target amount for said neighboring camera that are stored in said neighboring camera information storage unit, to multiply the determined provisional target code amount by a value indicating a free space in a transmission band of the transmission path that can be used by said communication interface unit for outputting the video, and to determine a resulting value as the target code amount to be assigned to said camera.

10. The monitoring system according to claim 1,

wherein said communication interface unit is further operable to obtain an instruction to change the distribution pattern, and

said collaboration parameter updating unit is operable to update the collaboration parameter so that the distribution pattern of the collaboration parameter matches the distribution pattern that has been changed according to the instruction obtained by said communication interface unit.

11. The monitoring system according to claim 1, further comprising

a surveillance monitor which is connected to the transmission path and which displays video,

wherein said communication interface unit is further operable to output, to said surveillance monitor, the video encoded by said video encoding unit, via the transmission path, and

said surveillance monitor receives and decodes encoded videos transmitted from said plural cameras, spatially synthesizes the decoded videos according to the positions of said plural cameras, and displays a resulting synthesized video.

12. monitoring system according to claim 11,

wherein said surveillance monitor displays the synthesized video so that, from among the videos transmitted from said plural cameras, a video having a large code amount is displayed with pictures of higher quality, larger size, or higher-level gradation.

13. monitoring system according to claim 11,

wherein said surveillance monitor performs edge enhancement processing on a video having a large code amount, and mosaic processing on a video having a small code amount, from among the videos transmitted from said plural cameras, and displays a synthesized video after each processing.

14. The monitoring system according to claim 1,

wherein each of said plural cameras further includes

a priority monitoring area storage unit which stores priority monitoring area information describing a collaboration method for determining, for each priority monitoring area, details of collaboration with the neighboring camera, the priority monitoring area being a place requiring intensive monitoring according to a layout of an area to be monitored, and

said collaboration parameter updating unit is further operable to update the collaboration parameter according to the collaboration method corresponding to the position of said camera, by checking the position of said camera against the priority monitoring area indicated by the priority monitoring area information.

15. The monitoring system according to claim 1,

wherein said object detecting unit is operable to detect an abnormal point in a monitoring target as the object.

16. A camera making up the monitoring system according to claim 1.

17. A video encoding method used in a camera in a monitoring system including plural cameras connected through a transmission path,

wherein each of said plural cameras includes:

an object detecting unit operable to detect an object that is a moving object to be monitored;

a video capturing unit operable to capture the object detected by said object detecting unit so as to obtain video;

a video encoding unit operable to encode the video obtained by said video capturing unit;

a collaboration parameter storage unit for storing a collaboration parameter indicating a relative amount of a target code amount assigned to a camera and a target code amount assigned to a neighboring camera, the target code amount being a target value in video encoding, and said neighboring camera being a predetermined camera, among said plural cameras, that is located near said camera;

a communication interface unit operable to exchange, by communicating with the neighboring camera, the collaboration parameter stored in said collaboration parameter storage unit of said camera and the target code amount assigned to said camera; and

a neighboring camera information storage unit for storing position identification information for identifying a position of said neighboring camera, as well as the collaboration parameter and the target code amount for said neighboring camera that are obtained by said communication interface unit, and

wherein said video encoding method includes;

a collaboration parameter updating step of updating the collaboration parameter stored in said collaboration parameter storage unit, based on a position of the object detected by said object detecting unit as well as the position identification information and the collaboration parameter of said neighboring camera that are stored in said neighboring camera positioning information unit so that;

(i) a distribution pattern, which indicates a distribution of a value of the collaboration parameter in a space in which said plural cameras are present, forms concentric circles having the object detected by said object detecting unit as an origin, and that (ii) the target code amount for a camera capturing the object becomes larger than the target code amount for a camera not capturing the object;

a target code amount determining step of determining the target code amount to be assigned to said camera, based on the collaboration parameter updated in said collaboration parameter updating step as well as the collaboration parameter and the target code amount for said neighboring camera that are stored in said neighboring camera information storage unit; and

a video encoding step of encoding the video so that an amount of code generated in the encoding attains the target code amount determined in said target code amount determining step.

18. A program which is executed in a camera in a monitoring system including plural cameras connected through a transmission path, said program causing a computer included in the camera to execute the steps included in the video encoding method according to claim 17.