This disclosure describes a system and a method for assigning pixels within agricultural imagery collected from overhead platforms to one or more classes based on spectral and/or spatial content. The system comprises one or more hardware processors configured by machine-readable instructions to: receive output signals provided by one or more remote sensing devices mounted to an overhead platform, the output signals conveying information related to one or more agricultural images; and assign pixels within the agricultural images to one or more classes based on spectral and/or spatial content of the agricultural images, wherein the one or more classes include a signal class and a noise class.