Hierarchical static shadow detection method
First Claim
1. A method for detecting shadow regions in an image, the steps comprising:
- a) providing an original image;
b) modeling said image as a reliable lattice (RL);
c) determining a relationship between said RL model and an Markov (MRF) model;
d) applying region level verification to said MRF model; and
e) identifying shadow regions in said original image from said MRF model.
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Abstract
There is provided a hierarchical shadow detection system for color aerial images. The system performs well with highly complex images as well as images having different brightness and illumination conditions. The system consists of two hierarchical levels of processing. The first level involves, pixel level classification, through modeling the image as a reliable lattice and then maximizing the lattice reliability using the EM algorithm. Next, region level verification, through further exploiting the domain knowledge is performed. Further analysis show that the MRF model based segmentation is a special case of the pixel level classification model. A quantitative comparison of the system and a state-of-the-art shadow detection algorithm clearly indicates that the new system is highly effective in detecting shadow regions in an image under different illumination and brightness conditions.
27 Citations
20 Claims
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1. A method for detecting shadow regions in an image, the steps comprising:
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a) providing an original image; b) modeling said image as a reliable lattice (RL); c) determining a relationship between said RL model and an Markov (MRF) model; d) applying region level verification to said MRF model; and e) identifying shadow regions in said original image from said MRF model. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for detecting probable shadow regions in an image, comprising:
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a) modeling the image as a reliable lattice having node reliabilities and link reliabilities; b) determining a relationship between the reliable lattice model and an Markov Random Field model to detect putative shadow regions; c) applying region level verification to the Markov Random Field model to remove false positive detected shadow regions; and d) storing identifications of non-false positive shadow regions.
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20. A method for detecting probable shadow regions within a two dimensional pixel image, comprising:
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a) modeling the image as a reliable lattice having node reliabilities and link reliabilities with respect to pixel shadow status classification; b) determining a relationship between the reliable lattice model of the image and an Markov Random Field model to detect likely shadow regions of the image; c) applying region level verification to the detected likely shadow regions in the image to detect false positive shadow regions in the image; and d) storing identifications of detected shadow regions in the image.
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Specification