Monitoring system and monitoring method

• US 7,212,650 B2
• Filed: 12/17/2002
• Issued: 05/01/2007
• Est. Priority Date: 06/14/2002
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Sumi, Noriaki
• Primary Examiner(s): Wu; Jingge
• Assistant Examiner(s): Ge; Yuzhen
• Application Number:
  US10/320,633
• Publication Number:
  US 20030231787A1
• Time in Patent Office: 1,596 Days
• Field of Search: 382/236
• 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 monitored object from the images picked-up by the image pick-up unit, determines a state of the monitored object, and transmits the image of the monitored object and the state of the monitored object; and

a display unit that receives and displays the image of the monitored object and the state of the monitored 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 non-monitored objects and the monitored object 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 each 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 a moving 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 moving background image from the difference image to extract an image of the monitored object without the moving background image; and

a determination unit that determines the state of the monitored object based on the barycentric positions and the difference image from the fluctuation extracting unit.

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 moving 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 moving background image.

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

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

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

7. A monitoring system according to claim 1, wherein the fluctuation extracting unit determines the moving object is the moving background image based on the barycentric position of the moving object not moving beyond a predetermined range.

8. A monitoring system according to claim 1, wherein the determination unit determines the state of the monitored object from displacement of the barycentric position based upon predetermined conditions.

9. A monitoring system according to claim 1, wherein the difference image is based on an absolute value of a difference of respective pixel values in two images.

10. 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 monitored object from the images picked-up by the image pick-up unit, determines a state of the monitored object, and transmits the image of the monitored object and the state of the monitored object; and

a display unit that receives and displays the image of the monitored object and the state of the monitored 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 non-monitored objects and the monitored object in the difference image to extract images of moving objects in the difference image;

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

determining an image of the moving object that may be considered as a moving 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 may be considered as the moving background image from the difference image to extract an image of the monitored object without the moving background image; and

determining the state of the monitored object based on the barycentric positions and the difference images without the moving background image.

11. The monitoring method according to claim 10, further comprising coloring the inside of the image of the monitored object.

12. The monitoring method according to claim 10, if there are a plurality of monitored objects, further comprising assigning a different character or a number or a symbol to each monitored object.

13. A monitoring method according to claim 10, further comprising the step of determining the moving object is the moving background image based on the barycentric position of the moving object not moving beyond a predetermined range.

14. A monitoring method according to claim 10, further comprising the step of determining the state of the monitored object from displacement of the barycentric position based upon predetermined conditions.

15. A monitoring method to claim 10, further comprising the step of determining the difference image is based on an absolute value of a difference of respective pixel values in two images.