Virtual inductance loop
Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for virtual inductance loop technology. In one aspect, a method includes calibrating, using calibration parameters, cameras directed towards a scene, obtaining, by the cameras, images corresponding to the scene, identifying reference structures in the scene, and determining, based on the reference structures and the images, locations in the scene for generating virtual inductance loop lines in the scene. The method also includes generating the virtual inductance loop lines to be imposed on the images, comparing the virtual inductance loop lines to determine one or more offsets, and determining, based on the offsets, characteristics of the scene.
1. A computer-implemented method, comprising:
obtaining, by each of two or more cameras directed towards a scene, an image corresponding to the scene;
determining, by one or more processors and for each of the images corresponding to the scene, a virtual inductance loop (VIL) line to be imposed on each of the images;
comparing, by the one or more processors, the VIL lines to determine one or more offsets; and
determining, by the one or more processors, based on the one or more offsets, one or more characteristics of the scene.
2. The method of claim 1 , wherein determining a VIL line to be imposed on each of the images comprises:
establishing a respective ground level plane at the scene; and
imposing the VIL line at the respective ground level plane at the scene.
3. The method of claim 1 , wherein obtaining, by each of the two or more cameras directed towards the scene, the image corresponding to the scene comprises synchronizing the images obtained by the two or more cameras.
4. The method of claim 1 , wherein determining one or more characteristics of the scene comprises determining a change in light intensity of the VIL lines, a change in color of the VIL lines, a predetermined length of a particular intensity of the VIL lines, or a predetermined length of a particular color along the VIL lines.
5. The method of claim 1 , comprising:
determining, based on the one or more characteristics of the scene, that an object has passed over the VIL line in a particular direction;
in response to determining that the object has passed over the VIL line, performing an action.
6. The method of claim 5 , wherein performing an action comprises triggering one or more of a mechanical computational process, an audible computational process, a visual computational process, or a subsequent computational process.
7. The method of claim 1 , wherein determining a VIL line to be imposed on each of the images comprises:
for each image:
identifying one or more identifiers at the scene;
determining a location for each of the one or more identifiers at the scene; and
generating the VIL line at the scene with respect to the locations of the one or more identifiers at the scene.
8. The method of claim 1 , wherein determining a VIL line to be imposed on each of the images comprises projecting, for each of the two or more cameras, the VIL line onto an image plane for each of the images corresponding to the scene.
9. The method of claim 1 , comprising:
generating one or more cross sectional outlines of an object that correspond to one or more intersections between the object and the VIL lines; and
determining, based on the one or more cross sectional outlines, whether the object has passed over the VIL line.
10. The method of claim 9 , wherein generating the one or more cross sectional outlines of the object comprises:
calculating, based on the one or more offsets, a height for each of the one or more characteristics; and
generating, based on the calculated heights for the one or more characteristics, the one or more cross sectional outlines of the object.
11. The method of claim 9 , wherein determining whether the object has passed over the VIL line comprises:
determining, using the one or more cross sectional outlines of the object, a size of the object; and
based on determining the size of the object, identifying the object.
12. The method of claim 9 , wherein determining whether the object has passed over the VIL line comprises determining, using the one or more cross sectional outlines of the object, one or more of a direction of motion of the object, whether the object is being tailgated, or whether the object is an oversized object.
13. A system, comprising:
two or more cameras directed towards a scene;
one or more processors in communication with the two or more cameras; and
one or more storage devices storing instructions that are operable, when executed by the one or more processors, to cause the one or more processors to perform operations comprising:
obtaining, by each of the two or more cameras, an image corresponding to the scene;
determining a virtual inductance loop (VIL) line to be imposed on each of the images;
comparing the VIL lines to determine one or more offsets; and
determining, based on the one or more offsets, one or more characteristics of the scene.
14. The system of claim 13 , wherein the operations of determining a VIL line to be imposed on each of the images comprises:
establishing a respective ground level plane at the scene; and
imposing the VIL line at the respective ground level plane at the scene.
15. The system of claim 13 , wherein the operations of obtaining, by each of the two or more cameras directed towards the scene, the image corresponding to the scene comprises synchronizing the images obtained by the two or more cameras.
16. The system of claim 13 , wherein the operations of determining one or more characteristics of the scene comprises determining a change in light intensity of the VIL lines, a change in color of the VIL lines, a predetermined length of a particular intensity of the VIL lines, or a predetermined length of a particular color along the VIL lines.
17. The system of claim 13 , wherein the operations comprise:
determining, based on the one or more characteristics of the scene, that an object has passed over the VIL line in a particular direction;
in response to determining that the object has passed over the VIL line, performing an action.
18. A non-transitory computer-readable medium storing software comprising instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform operations comprising:
obtaining, by each of two or more cameras directed towards a scene, an image corresponding to the scene;
determining a virtual inductance loop (VIL) line to be imposed on each of the images;
comparing the VIL lines to determine one or more offsets; and
determining, based on the one or more offsets, one or more characteristics of the scene.
19. The non-transitory computer-readable medium of claim 18 , wherein the operations of determining a VIL line to be imposed on each of the images comprises:
establishing a respective ground level plane at the scene; and
imposing the VIL line at the respective ground level plane at the scene.
20. The non-transitory computer-readable medium of claim 18 , wherein the operations of obtaining, by each of the two or more cameras directed towards the scene, the image corresponding to the scene comprises synchronizing the images obtained by the two or more cameras.