1. A method comprising: producing, by a processor, a frequency domain representation of a digital image comprising plants and identifying at least one desired patch in said frequency domain representation, according to predefined frequency characteristics of said desired patch; removing, by the processor, all frequencies outside said desired patch to obtain a masked frequency domain; and reverse transforming, by the processor, said masked frequency domain to obtain a reverse transformed image comprising spatial elements representing plant rows corresponding to said desired patch; wherein said predefined frequency characteristics comprise: at least one dominant frequency value; at least one predefined frequency characteristic corresponding to at least one predefined spatial characteristic relating to at least one attribute of said plants; or any combination thereof, and wherein the attribute includes one of: planted row spacing, spacing between plants on the same row and direction of plant rows.