Apparatus and method of location determination in a thermal imaging system
A camera assembly, including: an enclosure having at least two mounting surfaces that are orthogonal to each other for alignment with at least two orthogonal surfaces against which the camera assembly is to be mounted; at least one imaging apparatus disposed within the enclosure and having a predetermined orientation with respect to the enclosure; and a communication device disposed within the enclosure; and a server disposed at a location remote from where the camera is mounted. The camera assembly and the server communicate over a computer communication network to identify at least one mounting measurement of the camera assembly to establish a mapping from an image coordinate system for images generated by the imaging apparatus and a real world coordinate system aligned with an orientation defined by the at least two orthogonal surfaces.
1. A thermal imaging system, comprising:
at least one thermal camera assembly disposed in an area to generate images of the area;
a centralized server disposed at a location remote to the area, wherein:
the server is connected to the at least one thermal camera assembly via a computer communication network;
the thermal imaging system comprising a memory that stores a set of configuration parameters, wherein the set of configuration parameters identifies a pre-configured ratio between a size of an image of an item in an image coordinate system, the image generated by the thermal camera assembly, and a corresponding height of the item in a real world;
wherein the thermal imaging system is configured to:
(1) generate the pre-configured ratio during calibration of the thermal imaging system; and
(2) compute a mounting height of the thermal camera assembly in the real world based on the pre-configured ratio and a predetermined reference mounting height of the thermal camera assembly, the reference mounting height being from a mounting location of the thermal camera assembly to a reference floor in the image coordinate system; and
the thermal imaging system is configured to map using the mounting height as computed based on the ratio between: the size of the image of the item generated by the thermal camera assembly and the corresponding height of the item in the real world, the mapping performed from the image coordinate system of images generated by the thermal camera assembly to a real world coordinate system of the area.
2. The thermal imaging system of claim 1 , wherein the set of configuration parameters further identifies points of interest in the area in the image coordinate system, wherein the points of interest have locations in the images generated by the thermal camera assembly but not visible in the images generated by the thermal camera assembly.
3. The thermal imaging system of claim 2 , wherein the thermal imaging system identifies sizes and orientations of objects visible in the images generated by the thermal camera assembly, based on sizes and orientation of the objects as measured in the images generated by the thermal camera assembly and the set of configuration parameters; and the thermal imaging system generates monitoring alerts provided via an output device of the thermal camera assembly in reference to the points of interest in the area.
4. The thermal imaging system of claim 3 , wherein the set of configuration parameters includes another mounting height of the thermal camera assembly above a floor plane of the area, based on a statistical distribution of heights of thermal images of humans observed by the thermal camera assembly over a period of time.
5. The thermal imaging system of claim 1 , wherein the item is a person; the ratio is based on a height of the person measured in the real world and a height of the person measured in the image generated by the thermal camera assembly; and the thermal imaging system is configured to receive the height of the person measured in the real world from a user interface during a calibration operation and capture the image using the thermal camera assembly during the calibration operation.
6. The thermal imaging system of claim 5 , wherein the person is in a vertical position when the thermal camera assembly generates the image during the calibration operation; and an imaging plane of the thermal camera assembly is not in parallel with the vertical position of the person.
7. The thermal imaging system of claim 6 , wherein the size of the image of the item is computed based at least in part on a mounting angle of the thermal camera assembly relative to the vertical position.
8. The thermal imaging system of claim 1 , wherein the reference mounting height is smaller than the mounting height as computed.
9. The thermal imaging system of claim 1 , wherein the pre-configured ratio is set such that in response to a corresponding height of the item in the real world equaling the size of the image of the item in the image coordinate system, the pre-configured ratio equals a ratio between the reference mounting height and the mounting height as computed.