Systems and methods for adaptive cancellation of a moving metal object's effect on received signals

A method for adaptive cancellation of a moving metal object's effect on received signals, comprising:

• performing calibration operations comprising
• detecting, by a system controller of a metal detection system, an effect of a moving metal object of non interest (MMONI) upon on a first signal received at the metal detection system;
• determining a plurality of gain settings for an Analog Front End (“AFE”) of a receiver circuitry associated with the metal detection system, each of said plurality of gain settings corresponding to one of a plurality of regions through which the MMONI travels along a predefined motion path;
• selecting each of said plurality of gain settings to maintain an output of the AFE within a predetermined valid operating range while moving through each said region;
• after selecting said plurality of gain settings, determining a model comprising a set of model parameters to characterize the influence of the moving metal object on the first signal, said model relating a position of the MMONI to a predicted received signal amplitude;
• and
• following completion of the calibration operations
• determining a MMONI position as it traverses the predefined motion path;
• selecting for each region through which the MMONI travels a corresponding one of the plurality of gain settings, and a corresponding set of the model parameters applicable to the region;
• using the selected gain setting for each region to control AFE gain so as to maintain the output of the AFE within the predetermined valid operating range and thereby produce a gain controlled AFE output signal;
• and
• cancelling the effects of the moving metal object on the gain controlled signal by applying the model parameters to determine a modeled influence of the MMONI at each door position, and subtracting the modeled influence from the gain controlled AFE output signal.