We introduce the non-commutative f -divergence functional Theta( widetilde{A}, widetilde{B}):= int_TB_t^{ frac{1}{2}}f left(B_t^{- frac{1}{2}} A_tB_t^{- frac{1}{2}} right)B_t^{ frac{1}{2}}d mu(t) for an operator convex function f , where widetilde{A}=(A_t)_{t in T} and widetilde{B}=(B_t)_{t in T} are continuous fields of Hilbert space operators and study its properties. We establish some relations between the perspective of an operator convex function $f$ and the non-commutative f -divergence functional. In particular, an operator extension of Csisz {a}r s result regarding f -divergence functional is presented. As some applications, we establish a refinement of the Choi--Davis--Jensen operator inequality, obtain some unitarily invariant norm inequalities and give some results related to the Kullback--Leibler distance.

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