Method and apparatus for detecting changes in dynamic images
First Claim
1. An apparatus for detecting a moving object in dynamic images, comprising:
- image input means for sequentially taking input images of the moving object against a static background;
difference calculation means for obtaining difference images from successive input images taken by said image input means as picture elements;
noise model estimation means for estimating an appropriate noise model representing a lightness variation due to an image taking environmental condition under which the input images are taken by the image input means, the estimation being made according to the input images taken by the image input means and the difference images obtained by the difference calculation means by estimating values of noise model parameters in a regression model, and specifying a ratio of a difference in lightness at each picture element of each difference image with respect to an average difference in lightness over an entire imaging view field of each difference image as a function of lightness at each picture element in each input image expressed in terms of the noise model parameters;
change determining means for determining changed regions in the entire imaging view field by compensating for the lightness variation by subtracting from the difference images obtained by the difference calculation means an estimated lightness variation based on the noise model estimated by the noise model estimation means; and
detecting means for detecting the moving object in the dynamic images according to the changed regions determined by the change determining means.
0 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for detecting changes in dynamic images. The method and apparatus are capable of detecting movement at a high precision of a moving object against a static background, regardless of the variation of the image taking environmental condition, such as a lighting condition. In the apparatus, input images of a moving object are taken against a static background sequentially, and difference images are obtained from successive ones of the input images. Then, an appropriate noise model for a lightness variation due to an image taking environmental condition under which the input images are taken is estimated according to the input images and the difference images. Changed regions in an entire imaging view field are detected according to the input images, the difference images, and the appropriate noise model.
-
Citations
16 Claims
-
1. An apparatus for detecting a moving object in dynamic images, comprising:
-
image input means for sequentially taking input images of the moving object against a static background; difference calculation means for obtaining difference images from successive input images taken by said image input means as picture elements; noise model estimation means for estimating an appropriate noise model representing a lightness variation due to an image taking environmental condition under which the input images are taken by the image input means, the estimation being made according to the input images taken by the image input means and the difference images obtained by the difference calculation means by estimating values of noise model parameters in a regression model, and specifying a ratio of a difference in lightness at each picture element of each difference image with respect to an average difference in lightness over an entire imaging view field of each difference image as a function of lightness at each picture element in each input image expressed in terms of the noise model parameters; change determining means for determining changed regions in the entire imaging view field by compensating for the lightness variation by subtracting from the difference images obtained by the difference calculation means an estimated lightness variation based on the noise model estimated by the noise model estimation means; and detecting means for detecting the moving object in the dynamic images according to the changed regions determined by the change determining means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A method for detecting a moving object in dynamic images, comprising the steps of:
-
(a) sequentially taking input images of the moving object against a static background; (b) obtaining difference images as picture elements from successive input images taken at the step (a); (c) estimating an appropriate noise model representing a lightness variation due to an image taking environmental condition under which the input images are taken at the step (a), according to the input images taken at the step (a) and the difference images obtained at the step (b) by estimating values of noise model parameters in a regression model, and specifying a ratio of a difference in lightness at each picture element of each difference image with respect to an average difference in lightness over an entire imaging view field of each difference image as a function of lightness at each picture element in each input image expressed in terms of the noise model parameters; (d) determining changed regions in the entire imaging view field by compensating for the lightness variation by subtracting from the difference images obtained at the step (b) an estimated lightness variation based on the noise model estimated at the step (c); and (e) detecting the moving object in the dynamic images according to the changed regions determined at the step (d). - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
-
Specification