Design of DTCWT-DWT Image Compressor-Decompressor with Companding Algorithm

Abstract

Discrete Wavelet Transform (DWT) has demonstrated advantages in image compression due to its time-frequency resolution property. Dual Tree Complex Wavelet Transform (DTCWT) in addition to the advantages of DWT supports additional properties such as directionality and shift invariant. DTCWT has coefficient redundancy of 4:1 or 2 m :1 in m dimensions thus is four time complex than DWT computation. In this work, DTCWT based image compression algorithm is proposed that performs decomposition using DTCWT and reconstruction is carried out using DWT. The DTCWT bands are companded and encoded using entropy encoder and the quantization of the sub bands introduces minimum loss. The proposed algorithm achieves 77% compression with 40 dB PSNR thus suitable for real time image compression. DTCWT filters are appropriately selected to achieve perfect reconstruction.

Low Power Area Optimum Configurable 160 to 2560 Subcarrier Orthogonal Frequency Division Multiplexing Modulator-Demodulator Architecture based on Systolic Array and Distributive Arithmetic Look-Up Table

“…DTCWT filter structure as presented by Kingsbury requires 10-tap filter structure with four filter banks every stage. Systolic array algorithm for data processing is reported to achieve high throughput, reduced potential with reusability logic presented in Divakar et al [15]- [16]. The DTCWT architecture reported by Poornima et al [17] presents the design of systolic array architecture using multiplexed distributive arithmetic algorithm for image decomposition.…”