1. A non-transitory program storage device, readable by a processor and comprising instructions stored thereon to cause one or more processors to: apply an integrator function to a set of gradient signals to obtain a set of integrated signals; separately combine an input signal with each of the set of integrated signals to generate difference output signals; apply an invertible linear transform to each of the difference output signals to obtain a transform representation of the difference output signals; and adjust one or more components of the transform representation of the difference output signals based, at least in part, on an initial estimate of the adjusted one or more components to generate a modified transform representation.