1. A computer implemented method for wildfire detection using a visible range video camera, the computer performing steps comprising: generating sequential video images of a subject area; detecting gray colored regions in one of the video images; determining if a gray colored region is smooth; determining if a gray colored smooth region is slow moving by a frame difference comparison between a video image containing the gray colored smooth region and a past video image that is within a slow moving time range of the video image; determining if a slow moving gray colored smooth region is connected to a land portion of the subject area; constructing a covariance matrix of a land connected slow moving gray colored smooth region; and applying a trained support vector machine to the covariance matrix to determine if the land connected slow moving gray colored smooth region is smoke from a wildfire.