1. A method for enhancing a gathered lofargram data image comprising the steps of: segmenting the gathered lofargram data image into a series of vertical frequency strips, each frequency strip including a plurality of pixels; determining a mean and variance for the frequencies in each vertical frequency strip; adjusting the visibility of the pixels in each vertical frequency strip according to the determined mean and variance to generate a plurality of transformed vertical frequency strips; and recombining the transformed vertical frequency strips into an enhanced lofargram data image.