Concurrent error detection in wavelet lifting transforms

Wavelet transforms, central to multiresolution signal analysis and important in the JPEG2000 image compression standard, are quite susceptible to computer-induced errors because of their pipelined structure and multirate processing requirements. Such errors emanate from computer hardware, software bugs, or radiation effects from the surrounding environment. Implementations use lifting schemes, which employ update and prediction estimation stages, and can spread a single numerical error caused by failures to many output transform coefficients without any features to warn data users. This paper proposes an efficient method to detect the arithmetic errors using weighted sums of the wavelet coefficients at the output compared with an equivalent parity value derived from the input data. Two parity values may straddle a complete multistage transform or several values may be used, each pair covering a single stage. There is greater error-detecting capability at only a slight increase in complexity when parity pairs are interspersed between stages. With the parity weighting design scheme, a single error introduced at a lifting section can be detected. The parity computation operation is properly viewed as an inner product between weighting values and the data, motivating the use of dual space functionals related to the error gain matrices. The parity weighting values are generated by a combination of dual space functionals. An iterative procedure for evaluating the design of the parity weights has been incorporated in Matlab code and simulation results are presented.