The paper presents a comparison of performances and characteristics of a Self Scheduled linear parameter varying (LPV) Flux Observer and observation algorithms based on Kalman Filter for induction motor rotor flux estimation, inserted in a field oriented control scheme. The construction of the considered algorithms is described in detail, and the different design issues are explained. For true comparison the same measurements are assumed available to both deterministic and stochastic estimators, and the same controller parameters are used in simulation. The performances of the estimators are compared either in terms of observation errors during transient and steady state operations either in terms of robustness face to variations of motor parameters.