Scale space normalization technique for improved feature detection in uniform and non-uniform illumination changes
First Claim
1. A method operational in an image feature detection device, comprising:
- generating a difference of scale space image by taking the difference between two different smoothened versions of an image;
generating a normalized difference of scale space image by dividing the difference of scale space image by a third smoothened version of the image, where the third smoothened version of the image is as smooth or smoother than the smoothest of the two different smoothened versions of the image;
modifying both the difference of scale space image and the normalized difference of scale space image by an illumination scaling function; and
using the normalized difference of scale space image to detect one or more features for the image.
1 Assignment
0 Petitions
Accused Products
Abstract
A normalization process is implemented at a difference of scale space to completely or substantially reduce the effect that illumination changes has on feature/keypoint detection in an image. An image may be processed by progressively blurring the image using a smoothening function to generate a smoothened scale space for the image. A difference of scale space may be generated by taking the difference between two different smoothened versions of the image. A normalized difference of scale space image may be generated by dividing the difference of scale space image by a third smoothened version of the image, where the third smoothened version of the image that is as smooth or smoother than the smoothest of the two different smoothened versions of the image. The normalized difference of scale space image may then be used to detect one or more features/keypoints for the image.
13 Citations
33 Claims
-
1. A method operational in an image feature detection device, comprising:
-
generating a difference of scale space image by taking the difference between two different smoothened versions of an image; generating a normalized difference of scale space image by dividing the difference of scale space image by a third smoothened version of the image, where the third smoothened version of the image is as smooth or smoother than the smoothest of the two different smoothened versions of the image; modifying both the difference of scale space image and the normalized difference of scale space image by an illumination scaling function; and using the normalized difference of scale space image to detect one or more features for the image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 29, 30, 31, 32, 33)
-
-
10. An image feature detection device, comprising:
-
a difference of scale space generator adapted to generate a difference of scale space image by taking the difference between two different smoothened versions of an image; a difference of scale space generator normalizer adapted to generate a normalized difference of scale space image by dividing the difference of scale space image by a third smoothened version of the image, where the third smoothened version of the image is as smooth or smoother than the smoothest of the two different smoothened versions of the image; and a feature detector adapted to use the normalized difference of scale space image to detect one or more features for the image; wherein both the difference of scale space image and the normalized difference of scale space image are modified by an illumination scaling function. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
-
-
18. A image feature detection device, comprising:
-
means for generating a difference of scale space image by taking the difference between two different smoothened versions of an image; means for generating a normalized difference of scale space image by dividing the difference of scale space image by a third smoothened version of the image, where the third smoothened version of the image is as smooth or smoother than the smoothest of the two different smoothened versions of the image; means for using the normalized difference of scale space image to detect one or more features for the image; and means for modifying both the difference of scale space image and the normalized difference of scale space image by an illumination scaling function. - View Dependent Claims (19, 20, 21, 22, 23)
-
-
24. A non-transitory processor-readable medium having one or more instructions operational on an image feature detection device, which when executed by a processor causes the processor to:
-
generate a difference of scale space image by taking the difference between two different smoothened versions of an image; generate a normalized difference of scale space image by dividing the difference of scale space image by a third smoothened version of the image, where the third smoothened version of the image is as smooth or smoother than the smoothest of the two different smoothened versions of the image; and use the normalized difference of scale space image to detect one or more features for the image; wherein both the difference of scale space image and the normalized difference of scale space image are modified by an illumination scaling function. - View Dependent Claims (25, 26, 27, 28)
-
Specification