Kousuke Imamura

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This paper describes a sub-mW motion estimation processor core for MPEG-4 video encoding. It features a Gradient Descent Search algorithm whose computation power is only 7% of the conventional 1:4-subsampling search, producing higher picture quality. Another feature is an optimized SIMD datapath architecture to decrease a clock frequency and an operating(More)
An optical flow processor architecture is proposed. It offers accuracy and image-size scalability for video segmentation extraction. The Hierarchical Optical flow Estimation (HOE) algorithm [1] is optimized to provide an appropriate bit-length and iteration number to realize VLSI. The proposed processor architecture provides the following features. First,(More)
Vector quantization is the process of encoding vector data as an index to a dictionary or codebook of representative vectors. One of the most serious problems for vector quantization is the high computational complexity involved in searching for the closest codeword through the codebook. Entropy-constrained vector quantization (ECVQ) codebook design based(More)
In this paper, we propose two fast encoding algorithms for vector quantization. The first algorithm uses three significant features of a vector, that is , the norm, its projection angle to a reference line and the mean, to reduce the search area and accelerate the search process. The second algorithm has feature of using a suitable hyperplane to partition(More)
Developing an extremely efficient packet inspection algorithm for lookup engines is important to realize a high throughput and a lower energy dissipation. Previously, we proposed a mismatch detection circuit that detects mismatches with a minimal amount of memory accesses. In the present paper, we propose a new lookup engine based on the combination of a(More)
A high-efficiency video coding method using matching pursuits, which is a waveform coding technique, has recently been proposed. In this method, the motion compensated prediction error image is encoded by applying matching pursuits. In the present paper, we propose a matching pursuits coding method that encodes the sub-band images derived from motion(More)