A method includes determining a correlation between a first residual error and multiple columns in a sensing matrix according to a measured value of an original signal and the sensing matrix, and determining a first array most correlative to the measured value of the original signal in the sensing matrix according to the correlation between the first residual error and the multiple columns; determining a correlation between a kth residual error and the multiple columns according to a correlation between a (k−1)th residual error and the multiple columns, and determining a kth array most correlative to the measured value of the original signal according to the correlation between the kth residual error and the multiple columns in the sensing matrix, where 2≦k≦K; and recovering the original signal after determining a Kth array most correlative to the measured value of the original signal.