This paper describes two algorithms proposed for signal analysis in a pulse induction metal detector prototype. The first algorithm is based on combining Principal Component Analysis and Continuous Wavelet Transformation in order to determine metallic object position approaches to the detector coils, and the second algorithm is based on signal filtering in order to characterize object size. These algorithms have three functions; first, extracting time intervals in which the detector response gives information about an object approaching; second, the object position related to detector coils; third, information related to object size. The techniques used are based on time-frequency domains for raw signals acquired at the amplifier output in the prototype.