System and process for detecting, tracking and counting human objects of interest

• US 9,384,407 B2
• Filed: 04/25/2013
• Issued: 07/05/2016
• Est. Priority Date: 07/03/2007
• Status: Active Grant

• Current Assignee: Shoppertrak RCT LLC
• Original Assignee: Shoppertrak RCT Corporation (Johnson Controls International plc)
• Inventors: Wang, Zhiqian, Kastilahn, William C.
• Primary Examiner(s): NAKHJAVAN, SHERVIN K
• Application Number:
  US13/870,065
• Publication Number:
  US 20130236058A1
• Time in Patent Office: 1,167 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06F 18/28 Determining representative reference patterns, e.g. by averaging or distorting; Generating dictionaries
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10021 Stereoscopic video; Stereoscopic image sequence
• CPC Class Codes: G06T 2207/30242 Counting objects in image
• CPC Class Codes: G06T 7/285 using a sequence of stereo image pairs
• CPC Class Codes: G06T 7/292 Multi-camera tracking
• CPC Class Codes: G06V 10/62 relating to a temporal dimension, e.g. time-based feature extraction; Pattern tracking
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69

Abstract

A method of identifying, tracking, and counting human objects of interest based upon at least one pair of stereo image frames taken by at least one image capturing device, comprising the steps of: obtaining said stereo image frames and converting each said stereo image frame to a rectified image frame using calibration data obtained for said at least one image capturing device; generating a disparity map based upon a pair of said rectified image frames; generating a depth map based upon said disparity map and said calibration data; identifying the presence or absence of said objects of interest from said depth map and comparing each of said objects of interest to existing tracks comprising previously identified objects of interest; for each said presence of an object of interest, adding said object of interest to one of said existing tracks if said object of interest matches said one existing track, or creating a new track comprising said object of interest if said object of interest does not match any of said existing tracks; updating each said existing track; and maintaining a count of said objects of interest in a given time period based upon said existing tracks created or modified during said given time period.

Claims

1. A method of identifying and tracking objects of interest, comprising the steps of:

obtaining at least one pair of stereo image frames from more than one image capturing device and converting, by a processor, each said stereo image frame to a rectified image frame using calibration data obtained from the image capturing device;

generating a disparity map for each pair of stereo image frames;

converting the disparity map to a height map with local maxima;

identifying with the processor the presence or absence of said objects of interest by searching for objects of interest associated with the local maxima or suboptimal locations;

comparing with the processor each of said objects of interest to existing tracks comprising previously identified objects of interest;

for each said presence of an object of interest, adding, by the processor, said object of interest to one of said existing tracks if said object of interest matches said one existing track, or creating a new track with the processor comprising said object of interest if said object of interest does not match any of said existing tracks;

each existing track including location information indicative of a zone correlating to an area where the object of interest associated with the existing track was detected;

each new track including location information indicative of a zone correlating to an area where the object of interest associated with the new track was detected; and

using the location information to track the movement of objects of interest.

2. The method of claim 1, wherein each track further comprises a set of additional track attributes including, a status attribute for each said track taking one value from three possible values:

active, inactive, or deleted, wherein said status attribute is set to be active if said track comprises the object of interest in the most recent frame, inactive if said track does not comprise any object of interest in the most recent frame, and deleted if said track is marked for deletion and wherein the image capturing device includes a stereo camera.

3. A method of identifying and tracking objects of interest, comprising the steps of:

obtaining stereo image frames from more than one image capturing device;

generating a disparity map for each pair of stereo image frames;

converting the disparity map to a height map with local maxima;

identifying, by a processor, the presence or absence of detected objects of interest by searching for objects of interest associated with the local maxima or suboptimal locations;

comparing with the processor each of said detected objects of interest to existing tracks comprising previously identified objects of interest;

for each said presence of an object of interest, adding, by the processor, said object of interest to one of said existing tracks if said object of interest matches an existing track, or creating a new track with the processor comprising said object of interest if said object of interest does not match any of said existing tracks;

each existing track including location information indicative of a zone correlating to a first area where the previously identified object of interest associated with the existing track was detected;

each new track including location information indicative of a zone correlating to a second area where the detected object of interest associated with the new track was detected; and

using the location information to track the movement of the objects of interest.

4. The method of claim 3, wherein the image capturing device includes a stereo camera.

5. The method of claim 3, wherein a direction and speed of the objects of interest can be determined.

6. The method of claim 3, including the step of determining whether the objects of interest are moving into or out of the first area.

7. The method of claim 3, including the step of determining whether the objects of interest are moving into or out of the second area.

8. The method of claim 3, wherein the step of comparing the detected objects of interest to existing tracks includes using information representative of color for the detected objects of interest.

9. The method of claim 3, wherein the step of comparing the detected objects of interest to existing tracks includes using gray level intensity information.

10. The method of claim 3, wherein the suboptimal locations do not correspond with local maxima in the respective height map.

11. The method of claim 3, wherein the suboptimal locations are not associated with detected objects located in a background of the height map.

12. The method of claim 3, wherein the suboptimal locations are not associated with detected objects that are close to a boundary of the height map or a dead zone.