Gouraud明暗处理的探索

从Gouraud明暗处理模型的基本原理出发，以简单四面体为研究对象，分析了其数据结构和算法，并给出了核心代码。     

Gouraud明暗处理的深度探索

从Gouraud明暗处理模型的基本原理出发,以简单四面体为研究对象,分析了其数据结构和算法,并给出了核心代码.     

基于单幅图像明暗恢复形状算法设计

以单幅二维图像为研究对象,首先将彩色图像转换成灰度图像,然后直接寻找灰度值与缺失的第三维信息之间的关系,最后根据这种关系来求出物体表面缺失的第三维信息。整个算法流程简单,速度非常快,形状恢复满意度高。     

Phong明暗处理方法的探讨与改进

明暗处理是图形真实感处理的重要内容。物体明暗效果的模拟以光照模型为数学基础,通过不同算法模拟光照射在物体上的反射,透射等效果。文章以Phong局部光照模型为基础,分别用Gouraud方法和Phong方法实现了正方体单点光源光照模型,分析对比了两种方法的缺陷,在此基础上提出了P－G方法,成功模拟了多边形内部的高光并使光强度变化层次均匀。     

一种基于多面体模型的从明暗恢复物体形状方法

针对目前“从明暗恢复物体形状方法”存在的问题,提出了以多面体模型为基础的快速算法,根据向量场的分布建立关于物体表面深度信息的超定线性方程组,在最小二乘意义下求得物体表面的深度值。该算法能从已知光照条件下的单幅或多幅图像中恢复物体表面的三维结构,形成以像素为精度的物体表面多面体模型。实际计算表明该算法计算速度快,能适应单一反射系数的任意物体表面的形状恢复。     

三维实体明暗图的快速生成

本文在Ｄｅｌａｕｎａｙ三角剖分的基础上，充分利用ＳＧＩ工作站上的ＧＬ库中的库函数，提出了一种快速生成三维实体光照模型的算法。     

基于类比推理的物体明暗描绘方法

通过源图像与目标图像的类比关系,提取源图像中的物体在不同光照条件下生成的图像中的明暗知识,并将其作用于目标图像以完成明暗描绘．在目标图像与源图像上的绘制对象是理想漫反射物体且具有可类比性的情况下,绘制结果是合理的．该方法具有原始数据量小、计算速度快、便于显示效果的控制和交互等特点．     

基于OpenGL的等角插补明暗处理的软件实现

等角插补明暗处理具有Phong明暗处理的视觉效果,而且具有较Phong明暗处理更快的渲染效率,基于标准图形渲染管道,用Ｃ语言实现了OpenGL渲染管道的硬件计算部分,同时用Ｃ语言实现了等角插补明暗处理,并给出了实验结果。该方法的实现可为渲染算法的研究和实现提供参考。     

基于明暗恢复法的三维重建算法分析

明暗恢复形状法是计算机视觉领域的热门问题。明暗恢复法是通过一张照片的灰度信息恢复物体表面形状的一种方法。本文从数学角度度分析了SFS问题,并提出了三种解法:直接法求解,变分法求解和采用优化理论理论求解。并分析比较了这三种方法的适用范围和各自的典型算法。最后分析了SFS问题的发展趋势和难点问题。     

支持高级明暗处理和凸凹纹映射的硬件体系结构

Ｐｈｏｎｇ ｓｈａｄｉｎｇ和Ｂｕｍｐ ｍａｐｐｉｎｇ技术被认为是下一代图形硬件必须支持的技术技术,因而是目前图形硬件研究的重点,但到目前为止,尚未找到一种被广泛认可有效的硬件实现算法。本文对这一研究领域的一些实现方案做了初步的分析比较,试图找到一种有效的新的体系结构,它既能继承图形硬件已有的成果,又能对新的技术提供有效的支持。     

Influence on grip of knife handle surface characteristics and wearing protective gloves

Ten subjects were asked to apply maximum torques on knife handles with either their bare hand or their hand wearing a Kevlar fibre protective glove. Four knife handles (2 roughnesses, 2 hardnesses) were tested. Surface electromyograms of 6 upper limb and shoulder muscles were recorded and subject opinions on both knife handle hardness and friction in the hand were also assessed. The results revealed the significant influence of wearing gloves (p<0.0001), knife type (p<0.0005) and handle hardness (p<0.005) on the applied torque. Wearing Kevlar fibre gloves greatly increased the torque independently of the other two parameters. Under the bare hand condition, a 90° ShA slightly rough handle provided the greatest torque. Subject opinion agreed with the observed effects on recorded torque values except for the hardness factor, for which a preference for the 70° ShA value over the 90° ShA value emerged.     

Effects of handle orientation,gloves, handle friction and elbow posture on maximum horizontal pull and push forces

Biomechanical models were evaluated for effects of handle orientation, handle material, gloves and arm posture on maximal pull/push force. Eight healthy subjects performed maximum pull/push exertions on handles with two different orientations and two different surface materials, using bare hand and two types of glove as well as two arm postures. The empirical data supported the proposed biomechanical models: Pull/push forces for the bare hand on a rubber handle decreased 10% when the handle was parallel to the pull/push direction, compared with when perpendicular to it. For parallel handles, pull/push forces further decreased with decreasing hand–handle friction coefficient (simulated by different handle materials and gloves). Pull force exerted by the bare hand was 29% greater when the elbow was extended than when flexed. Pull force was greater than push force (with bare hand and flexed elbow). The biomechanical models suggest that friction between the hand and handle limits pull/push forces for parallel handles. Elbow strength may be responsible for decreased pull force for the flexed elbow posture and decreased force for pull compared with push in the postures examined.

Statement of Relevance: Biomechanical models presented in this paper provide insights for causes of upper extremity strength limitations during pull/push tasks. Findings in this paper can be used directly in the design of workstation and objects to reduce fatigue and risk of musculoskeletal disorders.     

A general framework for three-dimensional surface reconstruction by self-consistent fusion of shading and shadow features

In this paper a novel framework for three-dimensional surface reconstruction by self-consistent fusion of shading and shadow features is presented. Based on the analysis of at least two pixel-synchronous images of the scene under different illumination conditions, this framework combines a shape from shading approach for estimating surface gradients and altitude variations on small scales with a shadow analysis method that allows for the determination of the large-scale properties of the surface. As a first step, the result of shadow analysis is used for selecting a consistent solution of the shape from shading reconstruction algorithm. As a second step, an additional error term derived from the fine-structure of the shadow is incorporated into the reconstruction algorithm. This approach is extended to the analysis of two or more shadows under different illumination conditions leading to an appropriate initialization of the shape from shading algorithm. The framework is applied to the astrogeological task of three-dimensional reconstruction of regions on the lunar surface using ground-based CCD images and to the machine vision task of industrial quality inspection.     

Optimisation of a laparoscopic tool handle dimension based on ergonomic analysis

The techniques of Minimally Invasive Surgery (MIS) have quickly entered everyday surgical practice, and are steadily displacing traditional procedures. The reason is the advantages they have for the patient, both during surgery and in postoperative recovery. However, poor ergonomic design of the instruments used in MIS causes surgeons muscle fatigue and injuries (such as paraesthesia, etc.), forcing them to refrain from performing operations for several days or even weeks, which supposes costly losses of time and money.The objective of the present study was to optimize the handle size of a laparoscopic grasper tool. The study was conducted with the participation of 135 surgeons. Each participant performed a series of trials in which they executed the same action several times with the same tool (same in terms of the geometrical form of the handle) but of different dimensions (size) in order to determine the optimal diameter. The results were then subjected to a statistical analysis to study the relationship between the size of the surgeon's hand and the perceived optimal diameter of the handle from an ergonomic point of view.There stands out among the conclusions drawn from the study that there is indeed a relationship between the size of a surgeon's hand and the optimal handle size for them to use in surgery. In this sense, one of the most relevant results is that it is necessary to consider four different handle sizes groups (XS, S, M and L) instead of the three groups proposed by Greiner (1991). Another interesting result is that all surgeons in the smallest handle size group (XS) were women, and in the L group were men. Also it was interesting to note that, for the intermediate hand sizes (S and M), the sex of the surgeon conditioned the optimal handle size, and that the surgeon's experience and surgeon's handedness were not factors affecting the optimal diameter of the handle.Relevance to industryThe results of this work can assist designers of grasping tools in developing better handles and provide required sizing for improved comfort, performance and lowering the risk of cumulative traumatic disorders. It is important to note that it is not necessary to design the handle of the grasper tool for each surgeon hand, but also with four hand size categories is possible to offer an appropriate handle size for all surgeons independently of their hand sizes.     

结合小波变换的SFS最小化算法研究

提出了一种结合小波变换的从明暗恢复三维形状的最小化方法,该算法利用图像小波变换各个子频段的不同频率特性和方向特性,分别采用不同的算法重构。在图像被分解后的低频区域采用小波直接提取自然条纹相位,高频区域使用最小化方法重构。这种方法在低频区域避免了SFS最小化方法的假设条件,而高频区域又发挥了它对细节部分重构的优势。实验结果表明该算法比单独使用最小化方法的误差要小。     

基于MLX90620的低成本红外热成像系统设计

开发了一种基于非制冷红外焦平面阵列的红外热成像系统.为降低成本,系统选用具有16 pixel ×4 pixel输出像素的红外焦平面阵列探测器MLX90620进行红外辐射强度探测.为获得高分辨率、高质量的红外图像,提出一种将多项式插值与双线性插值相结合的算法,先利用多项式插值提升热像分辨率至64 pixel×16 pixel,再通过双线性插值算法扩充分辨率至256 pixel ×64 pixel,对人体进行热成像实验表明:该算法在提高图像分辨率的同时,保留了更多的细节信息.     

Effects of the handle diameter and tip angle of chopsticks on the food-serving performance of male subjects

The effects of chopsticks handle diameter and tip angle on the food-serving performance of pinching food, pulling food, shearing food and thrusting food, were investigated in this study. A total of 24 male subjects was tested using 12 pairs of experimental chopsticks, consisting of three types of different handle diameters and four types of different tip angles. These results indicated that chopstick handle diameter and tip angle have a significant influence on eating efficiency, and that these two variables have a significant interaction. In addition, chopstick tip diameter also had significant effects on performance at the four tasks and subjective ratings. Generally, according to the results, when the chopsticks design is presented in terms of handle diameter, tip angle and tip diameter, a pair of chopsticks with 6 mm handle diameter × 2 ° tip angle × 4 mm tip diameter would be optimum.     

The effects of tool handle shape on hand performance,usability and discomfort using masons' trowels

The effects of five new different handle shapes on hand performance capabilities, usability and discomfort, and also the relationship between these variables were evaluated in the context of masonry work and using masons’ trowels as an exemplar hand tool. The prototype handles were designed to provide different patterns of grip so that they could be suited to the hand/tool interaction in particular hand areas. The results showed significant effect of tool handle shape on the hand grip effort, usability, and hand and finger discomfort assessments, but not on the time to complete the masonry task. The hand grip effort and usability were negatively correlated with subjective assessment of hand and finger discomfort, so that a lower level of hand and finger discomfort corresponded to higher hand grip exertion and usability. These findings provide a better insight into the performance and usability issues when using hand tools which can be applied by tool manufacturers to improve industrial hand tool design.Relevance to industryThese findings present a unique insight into the handle design for industrial hand tool use and support the general conclusion that objective measurements should be supplemented by qualitative subjective assessments to provide a more holistic approach where specific and additional details about the hand tool design characteristics are incorporated from the workers' perspective.