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Power consumption is very critical for portable video applications such as portable videophone and digital camcorder. Motion estimation (ME) in the video encoder requires a huge amount of computation, and hence consumes the largest portion of power. We propose a novel method of reducing power consumption of the ME by adaptively changing the pixel resolution during the computation of the motion vector. The pixel resolution is changed by masking or truncating the least significant bits of the pixel data, which is governed by the bit-rate control mechanism. Experimental results show that on average more than 4 bits ran be truncated without significantly affecting the picture quality. This results in more than 60% reduction in power consumption.

The enormous growth of consumer electronic industry is driving the need for achieving ultra-high areal storage densities. Shingled magnetic recording (SMR) is a promising high density storage technique where shingles are created by overlapping tracks for increasing the track per inch (TPI) and achieving higher areal densities. High TPI values, however, introduce sidetrack interference in the equalized output of the center track sensed through the read head. The problem of removing interference from the center track signal can be formulated as estimating pulse shapes of sidetracks assuming sidetracks are decodable. In this paper, we first propose a solution using the correlation method for estimating the pulse shape and the phase-misalignment. The correlation method fails when there is a frequency offset present from sidetracks. Furthermore, we devise a solution based on the least mean square (LMS) algorithm which can provide time varying estimates of the sidetrack pulse shapes and remove the interference from the center track signal. Experimental and simulation results which corroborate the analysis of the proposed algorithm, demonstrate that the proposed algorithm outperforms other techniques and gives the minimum bit error rate (BER). The complexity of the proposed algorithm is low and it can be easily implemented on the hardware.

This paper describes a computer method for transforming an arbitrary developable surface into a flattened pattern. Developable surfaces are a special class of ruled surfaces. The Gaussian curvature of any point of the developable surfaces is zero. Some curves on developable surfaces are geodesic curves and the geodesic curvatures of all the points on these curves are zero. The flattening technique introduced in this paper is based on the geodesic curve length preservation and linear mapping principles. Both trimmed and untrimmed developable surfaces can be flattened by the algorithm.

With the advancement of computer techniques, a greater emphasis has been placed on intuitive human-computer interactions (HCIs). Virtual Reality systems can offer a novel way for users to interact with the objects in the computer generated environment (the so called Virtual Environment, VE). Through VR technology, we have the ability to replace the traditional input device, such as keyboard and mouse, with other modes such as speech and gesture. In our research project, we use a CyberGlove, developed by Virtual Technology Inc., as an input device to develop a desktop CAD modeling system for conceptual designers. We elaborate the limitations of the Dataglove and use gestures to support intuitive human-computer interface. To develop this gesture interface, we emphasize that conceptual designers are allowed full-freedom to use different kinds of gestures to conduct various geometric shape operations instead of depending solely on keyboard and 2D mouse. The designers can indicate objects or directions simply by pointing with the hand, and manipulate the position and orientation of an object by grasping and turning. The “virtual tools” can be used for shaping, cutting, and joining objects. We employ the 3D GUIs for enhancing the gesture interface. In the VE, the 3D menu and “virtual hand” float over the objects rather than being part of the scene. Various 3D cursors can be used to select menu or manipulate the object.

There is an increasing demand in the conceptual design for more intuitive methods for creating and modifying free-form curves and surfaces in CAD modeling systems. The methods should be based not only on the change of the mathematical parameters but also on the user’s specified constraints and shapes. This paper presents a new surface representation model for free-form surface deformation representation. The model is a combination of two functions: a displacement function and a function for representing an existing NURBS surface called parent surface. Based on the surface model, the authors develop two deformation methods which are named SingleDef (Single-point constraint based deformation method), and MultiDef (Multiple-points constraints based deformation method). The techniques for free-form surface deformation allow conceptual designer to modify a parent surface by directly applying point constraints to the parent surface. The deformation methods are implemented and taken in an experimental CAD system. The results show that the designer can easily and intuitively control the surface shape.

Power consumption is very critical for portable video applications such as portable video-phone. Motion estimation in the video encoder requires huge amount of computation and hence consumes the largest portion of power. In this paper we propose a novel method of reducing power consumption of the motion estimation by adaptively changing the pixel resolution during the computation of the motion vector. The pixel resolution is changed by masking or truncating the LSBs of the pixel data which is governed by an adaptive mechanism. Experimental results show that on average more than 4 bits can be truncated without affecting the picture quality. This results in an average 70% reduction in power consumption.

This paper presents a power evaluation framework designedfor estimating power consumption of a new video telephonecompression standard, ITU-H.263, at the system level.A hierarchical,mixed-level simulation environment is built andcycle-accurate power macro-modeling is used for the architecturalpower evaluation.Experimental results show the effectivenessof the proposed framework and models.

In this paper, methods for generating and flattening developable surfaces by means of two given directrix curves have been investigated. By finding the two end points of every generatrix, a developable surface may be formed. Such a developable surface may be flattened by rotating part of the surface about a generatrix. A new approach based on the principle of geodesic curve length preservation for flattening developable surfaces is also introduced. In this technique, an algorithm for evaluating the geodesic curvature of a point of a curve that lies on a surface is utilized.

Power consumption is very critical for portable video applications. Motion estimation in the video encoder requires huge amount of computation and hence consumes the largest portion of power. This paper investigates the power consumption of different motion estimation architectures. Full search architectures were used as an example to illustrate the power consumption mechanism. The principle can be extended to other commonly used fast search architectures. The result of this study can serve as a guideline for the selection of the appropriate architecture for portable applications.