The paper uses a frame-theoretic setting to study the injectivity of a ReLU-layer on the closed ball of ℝ^n and its non-negative part.In particular, the interplay between the radius of the ball and the bias vector is emphasized, which, together with a perspective from convex geometry leads to a computationally feasible method of verifying the injectivity of a ReLU-layer under reasonable restrictions in terms of an upper bound of the bias vector. Explicit reconstruction formulas are provided, ins…