Sobolev Duals for Random Frames and Sigma Delta Quantization of Compressed Sensing Measurements
Quantization of compressed sensing measurements is typically justified by the robust recovery results of CandSs, Romberg and Tao, and of Donoho. These results guarantee that if a uniform quantizer of step size delta is used to quantize m measurements y=I broken vertical bar x of a k-sparse signal xaa"e (N) , where I broken vertical bar satisfies the restricted isometry property, then the approximate recovery x (#) via a"" (1)-minimization is within O(delta) of x. The simplest and commonly assumed approach is to quantize each measurement independently. In this paper, we show that if instead an rth-order I I" pound (Sigma-Delta) quantization scheme with the same output alphabet is used to quantize y, then there is an alternative recovery method via Sobolev dual frames which guarantees a reduced approximation error that is of the order delta(k/m)((r-1/2)alpha) for any 0 <alpha < 1, if ma parts per thousand(3) (r,alpha) k(logN)(1/(1-alpha)). The result holds with high probability on the initial draw of the measurement matrix I broken vertical bar from the Gaussian distribution, and uniformly for all k-sparse signals x whose magnitudes are suitably bounded away from zero on their support.
random frames quantization compressed sensing finite frames alternative duals