Monitoring system and monitoring method

• US 20030231787A1
• Filed: 12/17/2002
• Published: 12/18/2003
• Est. Priority Date: 06/14/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Sumi, Noriaki
• Granted Patent: US 7,212,650 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: G08B 13/19686 Interfaces masking personal details for privacy, e.g. blurring faces, vehicle license plates

Abstract

A camera picks-up at least two images of a region where an object is present. A monitoring unit monitors the object and displays the images of the object on a display for a user. The monitoring unit obtains a difference image of the two images, and removes an image of a moving object that may be considered as a background image from the difference image to thereby obtain an image of the object. The monitoring unit determines the image of the moving object as the background image based on an area of the image of the moving object. The monitoring unit determines a state of the object based on barycentric positions of the images of the moving objects in the difference image.

Claims

1. A monitoring system comprising:

an image pick-up unit that obtains at least two images of a region where an object to be monitored is present at different timing;

a monitoring unit that extracts an image of the object from the images picked-up by the image pick-up unit, determines a state of the object, and transmits the image of the object and the state of the object; and

a display unit that receives and displays the image of the object and the state of the object for an observer,

the monitoring unit including

an outline extracting unit that obtains a difference image from the two images picked up by the image pick-up unit, extracts outlines of objects in the difference image to extract images of moving objects in the difference image;

an attribute processing unit that calculates areas and barycentric positions of the images of the moving objects in the difference image;

a fluctuation extracting unit that determines an image of the moving object that may be considered as the background image based on the area of the image of the moving object in the difference image and subtracts the image of the moving object that may be considered as the background image from the difference image to thereby extract an image of the object; and

a determination unit that determines the state of the object based on the barycentric positions.

2. The monitoring system according to claim 1, wherein the fluctuation extracting unit checks whether an amount of fluctuation in the area of an image of a moving object is larger than a predetermined value, and when the amount of fluctuation in the area is larger than the predetermined value determines the image of the moving object as the background image.

3. The monitoring system according to claim 1, wherein the fluctuation extracting unit checks whether an amount of movement of the barycentric position of an image of a moving object is within a predetermined region, and when the amount of movement of the barycentric position is within the predetermined region determines the image of the moving object as the background image.

4. The monitoring system according to claim 1, wherein the fluctuation extracting unit colors the inside of the image of the object.

5. The monitoring system according to claim 1, wherein if there are a plurality of the images of the objects, the fluctuation extracting unit colors each image of the object with a different color.

6. The monitoring system according to claim 1, wherein if there are a plurality of the images of the objects, the fluctuation extracting unit assigns a different character or a number or a symbol to each image of the object.

7. A monitoring method of monitoring an object present in a region using a monitoring unit, the monitoring unit including

an image pick-up unit that obtains at least two images of the region at different timing;

a monitoring unit that extracts an image of the object from the images picked-up by the image pick-up unit, determines a state of the object, and transmits the image of the object and the state of the object; and

a display unit that receives and displays the image of the object and the state of the object for an observer,

the monitoring method comprising;

obtaining a difference image from the two images picked up by the image pick-up unit;

extracting outlines of objects in the difference image to extract images of moving objects in the difference image;

calculating areas and barycentric positions of the images of the moving objects in the difference image;

determining an image of the moving object that may be considered as the background image based on the area of the image of the moving object in the difference image;

subtracting the image of the moving object that maybe considered as the background image from the difference image to thereby extract an image of the object; and

determining the state of the object based on the barycentric positions.

8. The monitoring method according to claim 7, further comprising coloring the inside of the image of the object.

9. The monitoring method according to claim 7, if there are a plurality of the images of the objects, further comprising assigning a different character or a number or a symbol to each image of the object.