1. A multimode touchless human machine interface (TLHMI) comprising: one or more touchless sensors to sense a position or a movement of a subject portion within a sensing zone of said one or more sensors; a tracking engine to receive an output of said one or more sensors and to: (a) track a movement of a portion of a computing platform user within the sensing zone to determine a gesture being performed by the portion of a computing platform user, within the sensing zone, and (b) determine one or more parameters of tracked movements of the portions of the user within the sensing zone; a mode transition module configured to monitor the determined one or more parameters of the motion, identify one or more mode transitioning parameters within the determined one or more parameters and determine a mode of operation of the TLHMI, based on the identified mode transitioning parameters; and a user input generator to convert an output of said tracking engine indicating the determined gesture into signals indicative of a user input and to provide said user input signals to a functionally associated computing platform, wherein said generator is adapted to generate: (1) a first output signal in response to a given determined gesture while the TLHMI is operating in a first mode of operation, and (2) a second output signal, which second output signal is a modification of the first output signal, in response to the same given determined gesture while the TLHMI is operating in a second mode of operation; wherein the modification of the first output signal is a modification of a ratio between the tracked movement and a movement of a control element of the computer platform associated with the input signals.