Methods and apparatus to improve detection and false alarm rate over image segmentation
View Patent ↗Methods, apparatus, systems and articles of manufacture are disclosed herein. An example method to improve object detection and false alarm rate over image segmentation includes overlaying a first object of a first image onto a second image. A first score based on a first chamfer distance between first edges of the first object and second edges in the second image is determined. A second score corresponding to a second chamfer distance between the second edges and a mathematical representation of a plurality of shapes is determined, the second score representing a similarity between the second edges and the plurality of shapes observed simultaneously. A normalized score is determined by normalizing the first score based on the second score. A presence of the second object in the second image matching the first object is detected based on whether the normalized score satisfies a threshold score.
1. A method to detect an object in an image comprising:
retrieving a first image of a first object and a second image of a search area;
determining a first score based on a first chamfer distance between first edges of the first object in the first image and second edges in the second image of the search area, the first chamfer distance being a first measure of pixel distances between portions of the first edges and the second edges;
determining a second score corresponding to a second chamfer distance between the second edges of the search area and a mathematical representation of a plurality of shapes, the second score representing a similarity between the second edges of the search area and the plurality of shapes observed simultaneously, the second chamfer distance being a second measure of pixel distances between portions of the second edges and the mathematical representation of the plurality of shapes;
determining a normalized score by normalizing the first score based on the second score; and
detecting a presence of a second object in the second image of the search area matching the first object when the normalized score satisfies a threshold score.
2. The method of claim 1 , wherein the second score represents a lesser similarity between the second edges and the plurality of shapes observed simultaneously than a second similarity between the second edges and any one of the plurality of shapes.
3. The method of claim 1 , wherein the plurality of shapes corresponding to the mathematical representation are representative of background clutter.
4. The method of claim 1 , wherein the second edges of the second image are edges of a retail store shelf.
5. The method of claim 1 , wherein determining the second score further includes cross-correlating the second edges with a matrix of ones having a same size as the first object.
6. An apparatus to detect an object comprising:
an image retriever to retrieve a first image of a first object and a second image of a search area;
an image scorer to determine a first score based on a first chamfer distance between first edges of the first object in the first image and second edges in the second image of the search area, the first chamfer distance being a first measure of pixel distances between portions of the first edges and the second edges;
the image scorer further to determine a second score corresponding to a second chamfer distance between the second edges of the search area and a mathematical representation of a plurality of shapes, the second score representing a similarity between the second edges of the search area and the plurality of shapes observed simultaneously, the second chamfer distance being a second measure of pixel distances between portions of the second edges and the mathematical representation of the plurality of shapes;
a normalizer to determine a normalized score by normalizing the first score based on the second score; and
an object detector to determine whether a second object matching the first object is present in the second image of the search area based on whether the normalized score satisfies a threshold.
7. The apparatus of claim 6 , wherein the second score represents a lesser similarity between the second edges and the plurality of shapes observed simultaneously than a second similarity between the second edges and any one of the plurality of shapes.
8. The apparatus of claim 6 , wherein the plurality of shapes corresponding to the mathematical representation are representative of background clutter.
9. The apparatus of claim 6 , wherein the second edges of the second image are edges of a retail store shelf.
10. The apparatus of claim 6 , wherein determining the second score further includes cross-correlating the second edges with a matrix of ones having a same size as the first object.
11. A tangible computer readable storage medium comprising instructions, that when executed, cause a computing device to at least:
retrieve a first image of a first object and a second image of a search area;
determine a first score based on a first chamfer distance between first edges of the first object in the first image and second edges in the second image of the search area, the first chamfer distance being a first measure of pixel distances between portions of the first edges and the second edges;
determine a second score corresponding to a second chamfer distance between the second edges of the search area and a mathematical representation of a plurality of shapes, the second score representing a similarity between the second edges of the search area and the plurality of shapes observed simultaneously, the second chamfer distance being a second measure of pixel distances between portions of the second edges and the mathematical representation of the plurality of shapes;
determine a normalized score by normalizing the first score based on the second score; and
determine whether a second object matching the first object is present in the second image of the search area based on whether the normalized score satisfies a threshold.
12. The tangible computer readable storage medium of claim 11 , wherein the second score represents a lesser similarity between the second edges and the plurality of shapes observed simultaneously than a second similarity between the second edges and any one of the plurality of shapes.
13. The tangible computer readable storage medium of claim 11 , wherein the plurality of shapes corresponding to the mathematical representation are representative of background clutter.
14. The tangible computer readable storage medium of claim 11 , wherein the second edges of the second image are edges of a retail store shelf.
15. The tangible computer readable storage medium of claim 11 , wherein determining the second score further includes cross-correlating the second edges with a matrix of ones having a same size as the first object.