Methods and apparatus to count people in images
Example apparatus disclosed herein include an analyzer to determine whether a first face rectangle is located in an overlap region of an image frame pair including a first image frame obtained from a first image sensor and a second image frame obtained from a second image sensor, the first face rectangle associated with the first image frame. Disclosed example apparatus also include a comparator to determine whether the first face rectangle is redundant to a second face rectangle when the first face rectangle is located in the overlap region of the image frame pair. Disclosed example apparatus further include an overlap eliminator to link first coordinates of the first face rectangle and second coordinates of the second face rectangle in a correlated face history when the first face rectangle is redundant to the second face rectangle, the correlated face history to identify redundant face rectangles in subsequent image frame pairs.
1. An apparatus comprising:
an analyzer to determine whether a first face rectangle is located in an overlap region of an image frame pair, the image frame pair including a first image frame obtained from a first image sensor and a second image frame obtained from a second image sensor different from the first image sensor, the first face rectangle associated with the first image frame obtained from the first image sensor;
a comparator to:
determine whether the first face rectangle is redundant to a second face rectangle associated with the second image frame obtained from the second image sensor when the first face rectangle is located in the overlap region of the image frame pair; and
eliminate the first face rectangle from a set of face rectangles when the first face rectangle is redundant to the second face rectangle; and
an overlap eliminator to link first coordinates of the first face rectangle and second coordinates of the second face rectangle in a correlated face history when the first face rectangle is redundant to the second face rectangle, the correlated face history to be searchable to identify redundant face rectangles in subsequent image frame pairs.
2. The apparatus of claim 1 , wherein the comparator is to search the correlated face history to determine whether image data corresponding to a subsequent image frame pair is to be analyzed.
3. The apparatus of claim 2 , wherein the analyzer is to determine coordinates of a third face rectangle detected in connection with an image frame of the subsequent image frame pair when the third face rectangle is located in the overlap region.
4. The apparatus of claim 3 , wherein the comparator is to compare coordinates corresponding to the third face rectangle of the image frame of the subsequent image frame pair to coordinates of the first face rectangle linked to the coordinates of the second face rectangle in the correlated face history when the first face rectangle is redundant to the second face rectangle and the third face rectangle is located in the overlap region.
5. The apparatus of claim 4 , wherein the comparator is to compare the coordinates of the third face rectangle to the coordinates of the first face rectangle in the correlated face history to determine whether the subsequent image frame pair includes redundant face rectangles.
6. The apparatus of claim 1 , further including a second overlap eliminator to further remove a third face rectangle from a first group of face rectangles associated with the first image sensor when the third face rectangle has similar image data as the first group of face rectangles.
7. The apparatus as defined in claim 1 , further including a score generator to generate a correlation score based on a comparison of features of the first face rectangle and features of the second face rectangle, the comparator to determine the first face rectangle is redundant to the second face rectangle based on the correlation score.
8. A tangible computer readable storage medium comprising instructions that, when executed, cause a processor to at least:
determine whether a first face rectangle is located in an overlap region of an image frame pair, the image frame pair including a first image frame obtained from a first image sensor and a second image frame obtained from a second image sensor different from the first image sensor, the first face rectangle associated with the first image frame obtained from the first image sensor;
determine whether the first face rectangle is redundant to a second face rectangle associated with the second image frame obtained from the second image sensor when the first face rectangle is located in the overlap region of the image frame pair;
eliminate the first face rectangle from a set of face rectangles when the first face rectangle is redundant to the second face rectangle; and
link first coordinates of the first face rectangle and second coordinates of the second face rectangle in a correlated face history when the first face rectangle is redundant to the second face rectangle, the correlated face history to be searchable to identify redundant face rectangles in subsequent image frame pairs.
9. The tangible readable storage medium as defined in claim 8 , wherein the instructions, when executed, further cause the processor to search the correlated face history to determine whether image data corresponding to a subsequent image frame pair is to be analyzed.
10. The tangible readable storage medium as defined in claim 9 , wherein the instructions, when executed, further cause the processor to determine coordinates of a third face rectangle detected in connection with an image frame of the subsequent image frame pair when the third face rectangle is located in the overlap region.
11. The tangible readable storage medium as defined in claim 10 , wherein the instructions, when executed, further cause the processor to compare coordinates corresponding to the third face rectangle of the image frame of the subsequent image frame pair to coordinates of the first face rectangle linked to the coordinates of the second face rectangle in the correlated face history when the first face rectangle is redundant to the second face rectangle and the third face rectangle is located in the overlap region.
12. The tangible readable storage medium as defined in claim 11 , wherein the instructions, when executed, further cause the processor to compare the coordinates of the third face rectangle to the coordinates of the first face rectangle in the correlated face history to determine whether the subsequent image frame pair includes redundant face rectangles.
13. The tangible readable storage medium as defined in claim 8 , wherein the instructions, when executed, further cause the processor to further remove a third face rectangle from a first group of face rectangles associated with the first image sensor when the third face rectangle has similar image data as the first group of face rectangles.
14. The tangible readable storage medium as defined in claim 8 , wherein the instructions, when executed, further cause the processor to:
generate a correlation score based on a comparison of features of the first face rectangle and features of the second face rectangle; and
determine the first face rectangle is redundant to the second face rectangle based on the correlation score.
15. A method comprising:
determining, by executing an instruction with a processor, whether a first face rectangle is located in an overlap region of an image frame pair, the image frame pair including a first image frame obtained from a first image sensor and a second image frame obtained from a second image sensor different from the first image sensor, the first face rectangle associated with the first image frame obtained from the first image sensor;
determining, by executing an instruction with the processor, whether the first face rectangle is redundant to a second face rectangle associated with the second image frame obtained from the second image sensor when the first face rectangle is located in the overlap region of the image frame pair;
eliminating, by executing an instruction with the processor, the first face rectangle from a set of face rectangles when the first face rectangle is redundant to the second face rectangle; and
linking, by executing an instruction with a processor, first coordinates of the first face rectangle and second coordinates of the second face rectangle in a correlated face history when the first face rectangle is redundant to the second face rectangle, the correlated face history to be searchable to identify redundant face rectangles in subsequent image frame pairs.
16. The method as defined in claim 15 , further including searching the correlated face history to determine whether image data corresponding to a subsequent image frame pair is to be analyzed.
17. The method as defined in claim 16 , further including determining coordinates of a third face rectangle detected in connection with an image frame of the subsequent image frame pair when the third face rectangle is located in the overlap region.
18. The method as defined in claim 17 , further including comparing coordinates corresponding to the third face rectangle of the image frame of the subsequent image frame pair to coordinates of the first face rectangle linked to the coordinates of the second face rectangle linked in the correlated face history when the first face rectangle is redundant to the second face rectangle and the third face rectangle is located in the overlap region.
19. The method as defined in claim 15 , further including removing a third face rectangle from a first group of face rectangles associated with the first image sensor when the third face rectangle has similar image data as the first group of face rectangles.
20. The method as defined in claim 15 , wherein the determining of whether the first face rectangle is redundant to the second face rectangle is based on a correlation score, and further including generating the correlation score based on features of the first face rectangle and features of the second face rectangle.