The changes of leaf’s top projected canopy area are closely bound up with the moisture in the plant the changes of the top projected canopy area is observed dynamicly and real-time

by applying CCD image sensors in the system.The growth-water irrigation for the plants in a greenhouse is guided by the information obtained from dynamic observations and aided by computers.The design and realization of the system are described from its hardware

software

and analysis and processing of leaves’image.It has been proved that the system can work steadily and monitor the changes of leaves’area accurately.It is significant to enrich the technology of water-saving irrigation and establish the foundations for the further research on the theory of lack of water of plant accroding to the changes of leaf’s area.