Disclosed herein are a method, apparatus and computer usable medium for linear filtering with filters of any desired shape and length using the wavelet transform as the computation engine by modifying the basis functions. Specifically, the method and apparatus modifies the basis function of the wavelet and/or inverse wavelet transform(s) by convolving it with the desired filter, thereby forming a modified wavelet and/or inverse wavelet transform(s). The linear filtering is performed in the signal processing and image processing related fields using the wavelet transform with a method that is mathematically equivalent to the filtering operation in the spatial domain. Linear filtering in the wavelet based domain eliminates the need for another program for software support or additional silicon area or real estate to accommodate more functions in hardware. The modified wavelet and/or inverse wavelet transform harnesses and leverages the wavelet and/or inverse wavelet basis function of the wavelet and/or inverse wavelet transform so as to perform the desired linear filtering of the digital or analog signals, without incurring extra cost in terms of software computations or hardware modifications.