1. A method for determining a horizon in a two-dimensional seismic section from an initial pick point on the horizon, the seismic section comprising a plurality of samples, wherein each sample is referenced using the variable x and y as the coordinates of the sample in the seismic section, the method comprising: convolving a set of optical filters with the seismic section to obtain a set of responses, wherein, for each sample, there are corresponding response values associated with the x and y coordinates of the sample, the optical filters having various center orientation values; determining an orientation vector for each sample based on the response value associated with the x and y coordinates of the sample; creating an orientation vector field comprising the orientation vectors of all the samples and storing the orientation vector field; and using a computer processor to determine the horizon by following the orientation vectors of the samples in the orientation vector field, beginning with the initial pick point on the horizon.