736 publications from this institution
This paper presents the design and testing of an image contour display system with vibrotactile array. The tactile image display system is attached on the user's back. It produces non-visual image and permits subjects to determine the position, size, shape of visible objects through vibration stimulus. The system comprises three parts: 1) a USB camera; 2) 48 (6×8) vibrating motors; 3) ARM micro-controlled system. Image is captured with the camera and the 2D contour is extracted and transformed into vibrotactile stimulus with a "contour following" (time-spatial dynamic coding) pattern. With this system subjects could identify the shape of object without special training; meanwhile fewer vibrotactile actuators are adopted. Preliminary experiments were carried out and the results demonstrated that the prototype was satisfactory and efficient for the visually impaired in seeing aid and environment perception.
This paper describes a method of generation of forces from a two-dimensional static image to make texture tangible using haptic devices. The proposed technique consists in creating a height map computed thanks to Tsai & Shah algorithm - an algorithm in shape-from-shading. This height map is then used to generate the virtual surface, and forces fields creating haptic texture are calculated by a new haptic texture rendering model.
A new optimum power calibration (OPC) algorithm for optical storage recording is proposed in this paper to provide accurate write power and write strategy settings for multisession recordings. This new OPC proposal, called "immediate optical power calibration" (IOPC), utilizes buffer zone A located in the intro area of the appended sessions to execute the OPC so that the recording area is exactly at the location where the OPC is executed. This methodology is very different from the current OPC being specified in the DVD + R/RW Specification , in which the OPC is executed at either the innermost or outermost OPC areas of a disk and the interpolation method is used to obtain the predicted power for recording. Since the IOPC is executed at a location on the disk exactly where it is to be recorded, the optimal write power and the write strategy settings obtained through the IOPC can thus provide more accurate writing power to achieve better jitter performance for recording. Most important, the IOPC is strictly compliant to the industry standards specified in DVD + R/RW Specifications to assure the recorded disk employing IOPC can be read back universally.
With one voltage feedback loop, the traditional voltage feedback readout circuit could access all elements in the two‐dimensional (2D) resistive sensor array with the shared row–column fashion but it suffered from the low readout rate problem for in it only one element could be selected and measured at the same time. First, the authors designed a novel readout circuit based on double voltage feedback loops (RC‐DVFLs) which could access two elements in the array simultaneously. Then, an approximate circuit model of the RC‐DVFL was presented and its mathematical equivalent resistance expressions of the elements being tested were analytically derived. Followed, the RC‐DVFL and its expressions were evaluated by simulation experiments and test experiments with a prototype circuit of the RC‐DVFL. The experiment results show that two elements in the 2D resistive sensor array can be accessed with the RC‐DVFL but only part crosstalk is suppressed, and the mathematical equivalent resistance expressions of the elements being tested can be used as the general formulas to evaluate the performance of the RC‐DVFL.
Multi-hop localization is a common method which is suitable for large-scale application. However, it is usually influenced by the network anisotropy, leading to the instability of the localization performance. In order to reduce the influence of the network anisotropy on the localization accuracy, this paper regards the localization as a regression forecasting process by constructing the mapping relationship between hop-counts and Euclidean distances among nodes. The method can effectively avoid the influence of anisotropy on localization, and it has low computation overhead and high localization accuracy without setting complex parameters. The simulation experimental results show that compared with the previous similar algorithms, the proposed algorithm can obtain a faster localization speed and a higher localization accuracy.
We propose a new design of a hardware accelerator for processing regular expression to speedup text search inside SSD storage (Processing in Storage: PIS). The unique features include parallel processing of 32 streams to quickly identify the first matched character under scan mode and match four characters concurrently under matching mode. In addition, we present a new approach of combining forward and backward scan to accomplish the first character search efficiently. Our experimental results show that the new parallel algorithm reduces the depth of logic circuit and the hybrid architecture performs as well as the Linux Grep algorithm does.
In accordance with the problem that the traditional trilateral or multilateral estimation localization method is highly dependent on the proportion of beacon nodes and the measurement accuracy, an algorithm based on kernel sparse preserve projection (KSPP) is proposed in this dissertation. The Gaussian kernel function is used to evaluate the similarity between nodes, and the location of the unknown nodes will be commonly decided by all the nodes within communication radius through selection of sparse preserve projection self-adaptation and maintaining of the topological structure between adjacent nodes. Therefore, the algorithm can effectively solve the nonlinear problem while ranging, and it becomes less affected by the measuring error and beacon nodes quantity.
Hybrid imaging modality combining ultrasound scanning and electrical current density imaging through the acoustoelectric (AE) effect may potentially provide solutions to imaging electrical activities and properties of biological tissues with high spatial resolution. In this study, a 3-D reconstruction solution to ultrasound current source density imaging (UCSDI) by means of Wiener deconvolution is proposed and evaluated through computer simulations. As compared to previous 2-D UCSDI problem, in a 3-D volume conductor with broadly distributed current density field, the AE signal becomes a 3-D convolution between the electric field and the acoustic field, and effective 3-D reconstruction algorithm has not been developed so far. In the proposed method, a 3-D ultrasound scanning is performed while the corresponding AE signals are collected from multiple electrode pairs attached on the surface of the imaging object. From the collected AE signals, the acoustic field and electric field were first decoupled by Wiener deconvolution. Then, the current density distribution was reconstructed by inverse projection. Our simulations using artificial current fields in homogeneous phantoms suggest that the proposed method is feasible and robust against noise. It is also shown that using the proposed method, it is feasible to reconstruct 3-D current density distribution in an inhomogeneous conductive medium.
