Device and method for detecting the presence of a logo in a picture

1. A method for detecting a presence of a logo in a current picture of a video comprising:

determining a current candidate logo bounding shape in said current picture and a preceding candidate logo bounding shape in a picture preceding said current picture;

calculating a first score value based at least partially on whether a distance between a center of said current and said preceding candidate logo bounding shapes is below a first threshold or whether an overlap between said current and said preceding candidate logo bounding shapes is above a second threshold;

calculating a second score value based at least partially on whether an overlap between the current candidate logo bounding shape and a saliency mask of the current picture is above a third threshold, wherein the saliency mask identifies regions around saliency peaks; and

detecting the presence of a logo in the current picture based at least partially on a comparison of the first score value and the second score value.

2. The method according to claim 1 , wherein said candidate logo bounding shape is a candidate logo bounding box.

3. The method according to claim 2 , further comprising,

increasing a confidence level by N each time the presence of a logo is detected for a current picture of said video; and

decreasing the confidence level by N each time the presence of a logo is not detected for a current picture, the presence of a logo being finally detected for the current picture when said confidence level is positive.

4. The method according to claim 3 , wherein N equals 1.

5. The method according to claim 3 , further comprising, increasing a value of N after several consecutive detections or non-detections are made.

6. The method according to claim 2 , further comprising:

checking whether the current candidate logo bounding box comprises a peak of saliency, when the presence of a logo is detected in the current picture; and

adding said current candidate logo bounding box to a list of logo candidate bounding boxes, when the current candidate logo bounding box comprises the peak of saliency, the logo in said current picture being a bounding box computed from the list of candidate logo bounding boxes when said list comprises M candidate logo bounding boxes and the logo in said current picture being the current candidate logo bounding box otherwise.

7. The method according to claim 6 , wherein M equals 10.

8. The method according to claim 2 , wherein determining the current candidate logo bounding box comprises:

computing an edge map for each picture of a detection window in at least one search area, said detection window comprising the current picture and P pictures preceding said current picture;

summing edge maps over the pictures into an accumulated edge map and binarizing the accumulated edge map;

filtering the binarized accumulated edge map into a filtered edge map;

binarizing the filtered edge map to into a map of blobs;

selecting, among the blobs containing pixels whose value in the filtered edge map is the highest, the blob containing the highest sum of pixel values in the filtered edge map ; and

determining a box bounding the selected blob, said candidate bounding box being said bounding box.

9. The method according to claim 8 , further comprising

sliding said detection window by k pictures; and

detecting a logo of a next picture, upon sliding said detection window.

10. The method according to claim 8 , wherein said at least one search area comprises four corners of the current picture and top and bottom horizontal banners.

11. A device for detecting a presence of a logo in a current picture of a video comprising:

a memory;

at least one processor configured to:

determine a current candidate logo shape in said current picture and a preceding candidate logo shape in a picture preceding said current picture;

calculate a first score value based at least partially on whether a distance between a center of said current and said preceding candidate logo bounding shapes is below a first threshold or whether an overlap between said current and said preceding candidate logo bounding shapes is above a second threshold;

calculate a second score value based at least partially on whether an overlap between the current candidate logo bounding shape and a saliency mask of the current picture is above a third threshold, wherein the saliency mask identifies regions around saliency peaks; and

detect the presence of a logo in the current picture based at least partially on a comparison of the first score value and the second score value.

12. The device according to claim 11 , wherein said candidate logo bounding shape is a candidate logo bounding box.

13. The device according to claim 12 , wherein the at least one processor is further configured to increase a confidence level by N each time the presence of a logo is detected for a current picture of said video and to decrease said confidence level by N otherwise, the presence of a logo being finally detected for the current picture when said confidence level is positive.

14. The device according to claim 13 , wherein N equals 1.

15. The device according to claim 13 , wherein the at least one processor is further configured to increase a value of N after several consecutive detections or non-detections are made.

16. The device according to claim 12 , wherein the at least one processor is further configured to:

determine a logo in said current picture when the presence of said logo is detected;

determine whether the current candidate logo bounding box comprises a peak of saliency; and

add said current candidate logo bounding box to a list of logo candidate bounding boxes if the current candidate logo bounding box comprises the peak of saliency, the logo in said current picture being a bounding box computed from the list of candidate logo bounding boxes when said list comprises M candidate logo bounding boxes and the logo in said current picture being the current candidate logo bounding box otherwise.

17. The device according to claim 16 , wherein M equals 10.

18. A non-transitory computer readable medium with instructions stored therein which, upon execution, instruct at least one processor to:

determine a current candidate logo bounding shape in a current picture and a preceding candidate logo bounding shape in a picture preceding said current picture;

calculate a first score value based at least partially on whether a distance between center of said current and said preceding candidate logo bounding shapes is below a first threshold or whether an overlap between said current and said preceding candidate logo bounding shapes is above a second threshold;

calculate a second score value based at least partially on whether an overlap between the current candidate logo bounding shape and a saliency mask of the current picture is above a third threshold, wherein the saliency mask identifies regions around saliency peaks; and

detect a presence of a loqo in the current picture based at least partially on a comparison of the first score value and the second score value.