Patent ID: 7822275

Claim:
A computer-based method for automatic detection of water regions in a video, the method comprising: generating a water map from the video; and outputting the water map to an output medium, wherein a computer performs generating the water map from the video, and wherein generating the water map comprises: a. estimating a water map of the video from video frames, wherein estimating the water map of the video comprises: i. storing a first frame of the video in memory as a reference frame; ii. initializing a variance map and the initial water map; iii. retrieving a next frame of the video and dividing the next frame into a grid of at least two blocks; iv. calculating a normalized correlation between the reference frame and each block in the next frame; v. calculating a gray scale gradient at each pixel in the next frame; vi. calculating the variance for each block in the grid by adding the variance of each pixel in the block; vii. repeating (iii) through (vi) for a specified number of next frames; viii. calculating a multiplicative product of the normalized correlation, the gray scale gradient, and the variance; ix. comparing the product with an average value of the multiplicative product over all blocks; x. marking a block as a water region in the initial water map when the product is greater than the average, and marking the block as a non-water region when the product is not greater than the average; and xi. repeating (viii) through (x) for each block, whereby the initial water map is created.