Low-complexity 8-point DCT approximations based on integer functions

Low-complexity 8-point DCT approximations based on integer functions

The discrete cosine transform (DCT) is widely regarded as a key operation in digital signal processing [15,51]. In fact, the Karhunen-Loève transform (KLT) is the asymptotic equivalent of the DCT, being the former an optimal transform in terms of decorrelation and energy compaction properties [1,15,18,23,37,51]. When high correlated first-order Markov signals are considered [15, 51]—such as nat...

Energy-efficient 8-point DCT Approximations: Theory and Hardware Architectures

Due to its remarkable energy compaction properties, the discrete cosine transform (DCT) is employed in a multitude of compression standards, such as JPEG and H.265/HEVC. Several low-complexity integer approximations for the DCT have been proposed for both 1-D and 2-D signal analysis. The increasing demand for low-complexity, energy efficient methods require algorithms with even lower computatio...

DCT Computation based on Variable Complexity Fast Approximations

Variable complexity DCT approximations driven by an HVQ-based analyzer

Transform approximations are explored for speeding up the software compression of images and video. Approximations are used to replace the regular discrete cosine transform (DCT) whenever only a few DCT coefficients are actually encoded. We employ a novel hierarchical vector quantization (HVQ)-based image analyzer to drive a bank of coders, thus switching to the fastest coder depending on the i...

VLSI Architecture for 8-Point AI-based Arai DCT having Low Area-Time Complexity and Power at Improved Accuracy

A low complexity digital VLSI architecture for the computation of an algebraic integer (AI) based 8-point Arai DCT algorithm is proposed. AI encoding schemes for exact representation of the Arai DCT transform based on a particularly sparse 2-D AI representation is reviewed, leading to the proposed novel architecture based on a new final reconstruction step (FRS) having lower complexity and high...