FIELD

The present invention relates to the field of occupancy sensing. Specifically, the invention relates to locating a specific occupant in a space.

BACKGROUND

Tracking and monitoring people are used in a variety of settings by military, civil, and commercial users, for example, by authorities for safety and security applications or by companies for tracking company employees.

Most tracking and monitoring methods use GPS to track devices, a common example of such devices being cellular phones. Such tracking methods do not directly track a person but rather track a device associated with a particular person.

Algorithms for detecting people in images are being developed and may be used to track people rather than devices associated with people. However, determining that a moving object in an image is a person and more so determining the identity of a moving person is a difficult task which largely depends on the angle of view of the cameras and other aspects of the setup of the space being monitored by the cameras. Existing people detecting and/or tracking solutions, although enabling to identify a person in a single image, do not enable continuous tracking of an identified person, especially in complex real world scenes that commonly involve multiple people, occlusions, and cluttered or moving backgrounds.

Thus, using people detecting algorithms to track and monitor specific people's locations from images is, to date, greatly limited.

SUMMARY

Methods and systems according to embodiments of the invention enable to locate a particular person within a monitored space. More so, embodiments of the invention enable locating a particular person within a monitored space without transmitting images of the space, thereby protecting privacy of occupants in the space.

In one embodiment of the invention an object in an image is initially identified as a particular occupant in a space, after which the object is tracked in images of the space. The particular identified occupant may then be located within the space based on the tracking of the object, without having to again identify the particular occupant or validate the occupant's identity.

An identity of a particular occupant may be determined by means of image analysis or other means. In one embodiment of the invention an object representing an occupant is detected in an image of the space. The identity of the occupant is determined and a unique identity is then associated with the object in the image. Once a unique identity is associated with a particular object in an image, the object may be tagged or named. Thereafter a system of cameras may track the tagged or named object in images of the space thereby tracking an identified occupant without having to verify the identity of the occupant during the tracking.

Embodiments of the invention enable tracking a particular person (or other occupant) using cameras located at any desired angle or view point. Cameras may thus be positioned within a space, such as a building, based on considerations such esthetics or ease of use for building operators and not based on considerations relating to tracking of occupants.

In some embodiments, a method (and system for performing the method) for locating a person in a space includes obtaining images of the space from first and second cameras, determining that an object in an image obtained from the first camera is a person (e.g., by applying computer vision algorithms on the image) and assigning a unique identity to the object. The object is then tracked throughout images obtained from the first camera and the second camera and the person can be located within the space based on the tracking and based on the unique identity.

The unique identity can be assigned to the object based on image analysis of the images of the space. In other embodiments a signal initiated by the person is received and the unique identity is assigned based on the received signal.

In some embodiments the object is tracked using a descriptor associated with the object. A descriptor may include one or a combination of components, such as appearance characteristics, location of the object, size and/or shape features of the object, etc.

The method may include receiving information from the first camera and tracking the object in the images obtained from the second camera based on the information received from the first camera. A descriptor associated with an object, such as a person, in the images obtained from the first and second cameras, can be extracted or created from the received information. Descriptors of objects from two images may be compared by using a dynamic metric, to determine if the object in both images is the same, to enable accurate tracking of an occupant in a space.

Using a descriptor which includes a combination of components enables a broader range by which to uniquely identify each object and using a dynamic metric by which to compare the descriptors of objects in two different images, enables to adjust the comparison to different situations, providing higher accuracy in determining objects in two different images are the same object, thereby enabling more robust tracking of occupants within a space.

In some embodiments the method includes detecting a direction of motion of the object in images obtained from the first camera and tracking the object in images obtained by the second camera based on the detected direction.

In some embodiments the method includes tracking the object in the images obtained by the second camera based on shape features of the object detected in the images obtained by the first camera.

Embodiments of the invention enable assigning a unique identity to the object retroactively, e.g., after determining that the object is a person and/or after assigning the unique identity to the object. The unique identity may be assigned retroactively to the object in previously stored images, namely images stored prior to determining that the object is a person and/or after assigning the unique identity to the object.

