A system and method are presented for use in monitoring one or more conditions of a subject's body. The system comprises a control unit which comprises an input port for receiving image data and data indicative of at least one external stimulation (external field) applied to a portion of the subject's body during collection of the image data therefrom, a memory utility, and a processor utility. The image data is indicative of a sequence of speckle patterns generated by the portion of the subject's body according to a certain sampling time pattern. The processor utility is configured and operable for carrying out the following: processing the image data utilizing the data indicative of the applied external field(s), said processing comprising determining a spatial correlation function between successive speckle patterns in the sequence, and determining a time varying spatial correlation function in the form of a time-varying function of at least one feature of the correlation function indicative of a change of the speckle pattern over time； selecting at least one parameter of the time-varying spatial correlation function, and applying to said at least one parameter one or more of the models to determine one or more corresponding body conditions； and generating output data indicative of said one or more corresponding body conditions.
