Tag: Affine transformation

 
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A Multiplication-Free Algorithm and A Parallel Architecture for Affine Transformation

Affine transformation is widely used in image processing. Recently, it is recommended by MPEG-4 for video motion compensation. This paper presents a novel low power parallel architecture for texture warping using affine transformation (AT). The architecture uses a novel multiplication-free algorithm that employs the algebraic properties of the AT. Low power has been achieved at different levels of the design. At the algorithmic level, replacing multiplication operations with bit shifting saves the power and delay of using a multiplier. At the architecture level, low power is achieved by using parallel computational units, where the latency constraints and/or the operating latency can be reduced. At the circuit level, using low power building blocks (such as low power adders) contributes to the power savings. The proposed architecture is used as a computational kernel in video object coders. It is compatible with MPEG-4 and VRML standards. The architecture has been prototyped in 0.6 μm CMOS technology with three layers of metal. The performance of the proposed architecture shows that it can be used in mobile and handheld applications.

 

Wael Badawy and Magdy Bayoumi, “A Multiplication-Free Algorithm and A Parallel Architecture for Affine Transformation,” The Journal of VLSI Signal Processing-Systems, Kluwer Academic Publishers, Vol. 31, No 2, May 2002, pp. 173-184.

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A Low Power VLSI Architecture for Mesh-based Video Motion Tracking

This paper proposes a low-power very large-scale integration (VLSI) architecture for motion tracking. It uses a hierarchical adaptive structured mesh that generates a content-based video representation. The proposed mesh is a coarse-to-fine hierarchical two-dimensional mesh that is formed by recursive triangulation of the initial coarse mesh geometry. The structured mesh offers a significant reduction in the number of bits that describe the mesh topology. The motion of the mesh nodes represents the deformation of the video object. The architecture consists of motion estimation and motion compensation units. The motion estimation architecture generates a progressive mesh code and the motion vectors of the mesh nodes. It reduces the power consumption, uses a simpler approach for mesh construction, approximates the mesh nodes motion vector by using the three step search algorithm and uses a parallel motion estimation core to evaluate the mesh nodes motion vectors. Moreover, it maximizes the lifetime of the internal buffers. The motion compensation architecture uses a multiplication-free algorithm for affine transformation, which significantly reduces the complexity of the motion compensation architecture. Moreover, using pipelined affine units contributes to the power savings. The video motion compensation architecture processes a reference frame, mesh nodes and motion vectors to predict a video frame. It implements parallel threads in which each thread implements a pipelined chain of scalable affine units. This motion compensation algorithm allows the use of one simple warping unit to map a hierarchical structure. The affine unit warps the texture of a patch at any level of hierarchical mesh independently. The processor uses a memory serialization unit, which interfaces the memory to the parallel units. The architecture has been prototyped using top-down low-power design methodology. The performance analysis shows that this processor can be used in online object-based video applications such as in MPEG and VRML.

Published in:

Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on  (Volume:49 , Issue: 7 )

Wael Badawy and Magdy Bayoumi, “A Low Power VLSI Architecture for Mesh-based Video Motion Tracking,” The IEEE Transactions on Circuits and Systems II, Vol. 49, July 2002, pp. 488-504.

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A Low Power Architecture for HASM Motion Tracking

This paper proposes low power VLSI architecture for motion tracking that can be used in online video applications such as in MPEG and VRML. The proposed architecture uses a hierarchical adaptive structured mesh (HASM) concept that generates a content-based video representation. The developed architecture shows the significant reducing of power consumption that is inherited in the HASM concept. The proposed architecture consists of two units: a motion estimation and motion compensation units.

The motion estimation (ME) architecture generates a progressive mesh code that represents a mesh topology and its motion vectors. ME reduces the power consumption since it (1) implements a successive splitting strategy to generate the mesh topology. The successive split allows the pipelined implementation of the processing elements. (2) It approximates the mesh nodes motion vector by using the three step search algorithm. (3) and it uses parallel units that reduce the power consumption at a fixed throughput.

The motion compensation (MC) architecture processes a reference frame, mesh nodes and motion vectors to predict a video frame using affine transformation to warp the texture with different mesh patches. The MC reduces the power consumption since it uses (1) a multiplication-free algorithm for affine transformation. (2) It uses parallel threads in which each thread implements a pipelined chain of scalable affine units to compute the affine transformation of each patch.

The architecture has been prototyped using top-down low-power design methodology. The performance of the architecture has been analyzed in terms of video construction quality, power and delay.

Wael Badawy and Magdy Bayoumi “A Low Power Architecture for HASM Motion Tracking,” The Journal of VLSI Signal Processing Systems for Signal, Image, and Video Technology, May 2004, Vol. 37, Issue 1, pp. 111-127

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Algorithm-Based Low Power VLSI Architecture For 2d-Mesh Video Object Motion Tracking

The new VLSI architecture for video object (VO) motion tracking uses a novel hierarchical adaptive structured mesh topology. The structured mesh offers a significant reduction in the number of bits that describe the mesh topology. The motion of the mesh nodes represents the deformation of the VO. Motion compensation is performed using a multiplication-free algorithm for affine transformation, significantly reducing the decoder architecture complexity. Pipelining the affine unit contributes a considerable power saving. The VO motion-tracking architecture is based on a new algorithm. It consists of two main parts: a video object motion-estimation unit (VOME) and a video object motion-compensation unit (VOMC). The VOME processes two consequent frames to generate a hierarchical adaptive structured mesh and the motion vectors of the mesh nodes. It implements parallel block matching motion-estimation units to optimize the latency. The VOMC processes a reference frame, mesh nodes and motion vectors to predict a video frame. It implements parallel threads in which each thread implements a pipelined chain of scalable affine units. This motion-compensation algorithm allows the use of one simple warping unit to map a hierarchical structure. The affine unit warps the texture of a patch at any level of hierarchical mesh independently. The processor uses a memory serialization unit, which interfaces the memory to the parallel units. The architecture has been prototyped using top-down low-power design methodology. Performance analysis shows that this processor can be used in online object-based video applications such as MPEG-4 and VRML

Wael Badawy and Magdy Bayoumi, “Algorithm-Based Low Power VLSI Architecture For 2d-Mesh Video Object Motion Tracking,” The IEEE Transaction on Circuits and Systems for Video Technology, Vol. 12, No. 4, April 2002, pp. 227-237

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An Affine Based Algorithm and SIMD Architecture for Video Compression with Low Bit-rate Applications

This paper presents a new affine-based algorithm and SIMD architecture for video compression with low bit rate applications. The proposed algorithm is used for mesh-based motion estimation and it is named mesh-based square-matching algorithm (MB-SMA). The MB-SMA is a simplified version of the hexagonal matching algorithm [1]. In this algorithm, right-angled triangular mesh is used to benefit from a multiplication free algorithm presented in [2] for computing the affine parameters. The proposed algorithm has lower computational cost than the hexagonal matching algorithm while it produces almost the same peak signal-to-noise ratio (PSNR) values. The MB-SMA outperforms the commonly used motion estimation algorithms in terms of computational cost, efficiency and video quality (i.e., PSNR). The MB-SMA is implemented using an SIMD architecture in which a large number of processing elements has been embedded with SRAM blocks to utilize the large internal memory bandwidth. The proposed architecture needs 26.9 ms to process one CIF video frame. Therefore, it can process 37 CIF frames/s. The proposed architecture has been prototyped using Taiwan Semiconductor Manufacturing Company (TSMC) 0.18-μm CMOS technology and the embedded SRAMs have been generated using Virage Logic memory compiler.

Published in:

Circuits and Systems for Video Technology, IEEE Transactions on  (Volume:16 ,  Issue: 4 )

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Mohammed Sayed , Wael Badawy, “An Affine Based Algorithm and SIMD Architecture for Video Compression with Low Bit-rate Applications“, IEEE Transactions on Circuits and Systems for Video Technology, Vol. 16, Issue 4, pp. 457-471, April 2006. Abstract