Methods for discriminating moving objects in motion image sequences
View Patent ↗In an exemplary embodiment of the present invention, an automated, computerized method is provided for classifying pixel values in a motion sequence of images. According to a feature of the present invention, the method comprises the steps of determining spectral information relevant to the sequence of images, and utilizing the spectral information to classify a pixel as one of background, shadow and object.
1. An automated, computerized method for classifying pixel values in a motion sequence of images, comprising the steps of:
a computer executing the following steps:
determining spectral information relevant to the sequence of images, the spectral information including a characteristic spectral ratio for the background; and
utilizing the spectral information to classify a pixel as one of background, shadow and object.
2. The method of claim 1 , wherein the step of utilizing the spectral information to classify a pixel as one of background, shadow and object is carried out by:
determining a characteristic spectral ratio for a static background of the sequence of images;
calculating, for a subject pixel of an image in the sequence, a spectral ratio between the subject pixel and a corresponding pixel of the static background; and
comparing the spectral ratio for the subject pixel to the characteristic spectral ratio.
3. The method of claim 2 , wherein the spectral ratio for the subject pixel is a normalized spectral ratio.
4. A computer system comprising:
a CPU; and
a memory storing a sequence of images;
the CPU arranged and configured to execute a routine to determine spectral information relevant to the sequence of images, wherein the spectral information comprises a characteristic spectral ratio for the background, and utilize the spectral information to classify a pixel as one of background, shadow and object.
5. An automated, computerized method for classifying pixel values in a motion sequence of images, comprising the steps of:
a computer executing the following steps:
determining spectral information relevant to the sequence of images, the spectral information including a BIDR cylinder representation of pixel values, in a color space; and
utilizing the spectral information to classify a pixel as one of background, shadow and object.
6. The method of claim 5 , wherein the step of utilizing the spectral information to classify a pixel as one of background, shadow and object is carried out by:
generating a BIDR cylinder representative of values of a subject pixel location throughout the sequence of images; and
comparing a value of the subject pixel location in one image, to the BIDR cylinder.
7. The method of claim 5 , wherein the color space is an RGB space.
8. The method of claim 6 , wherein the BIDR cylinder representative of values of a subject pixel location throughout the sequence of images, comprises a temporal linear token of pixel values at the location.
9. The method of claim 6 , wherein the step of generating a BIDR cylinder representative of values a subject pixel location throughout the sequence of images is carried out by calculating state probabilities for pixel values at the subject pixel location, and generating the BIDR cylinder representation as a function of the state probabilities.
10. The method of claim 9 , wherein the step of calculating state probabilities for pixel values at the subject pixel location is carried out by utilizing a Gaussian mixture model.
11. A computer system comprising:
a CPU; and
a memory storing a sequence of images;
the CPU arranged and configured to execute a routine to determine spectral information relevant to the sequence of images, wherein the spectral information comprises a BIDR cylinder representation of pixel values, in a color space, and utilize the spectral information to classify a pixel as one of background, shadow and object.
12. A computer program product, disposed on a computer readable media, the product including computer executable process steps operable to control a computer to:
provide a sequence of image files, each depicting an image, in a computer memory;
determine spectral information relevant to the sequence of images, wherein the spectral information comprises a characteristic spectral ratio for the background; and
utilize the spectral information to classify a pixel as one of background, shadow and object.
13. A computer program product, disposed on a computer readable media, the product including computer executable process steps operable to control a computer to:
provide a sequence of image files, each depicting an image, in a computer memory;
determine spectral information relevant to the sequence of images, wherein the spectral information comprises a BIDR cylinder representation of pixel values, in a color space; and
utilize the spectral information to classify a pixel as one of background, shadow and object.