Abstract:

In order to resolve low efficiency of hardware implementation of 2-dimension (2-D) discrete wavelet transform (DWT) based on the method for space time delay and integration charge coupled devices (TDICCD) compression system, a fast implementation structure (128,<em>N</em>) of 2-D lifting-based DWT is proposed. In the direction of line of CCD image, 16 modules of the fast implementation structure of 1-dimension(1-D) line lifting-based DWT are used to decompose image in parallel. Each module uses the value of four delay registers as the intermediate value to compute line wavelet coefficient, which is computed by a fusion structure of two step of prediction and updating. In the direction of line wavelet coefficient, a (32, 16) column lifting-based DWT structure based on multiplexing technology is proposed, which finally completes 2-D lifting-based DWT. The experiment results show that a module of 2-D lifting-based DWT can work fast and stably. The time needed in decomposing a frame image is only 60.198μs. Compared with traditional approaches, the time consuming is decreased by 49.90%, logical resource is decreased by 10.71%, register is decreased by 11.80%, and memory is decreased by 12.98%. Low efficiency of hardware implementation of wavelet module of CCD image compression in space camera is effectively improved.

Key words: space time delay and integration charge coupled camera, 2-dimension lifting-based discrete wavelet transform, tree structure of lifting-based wavelet transform