绘画创作意象论

中国古典美学体系实质上是以"意象"为基础范畴的审美本体体系,绘画美学则侧重于从艺术的角度看待审美,所以"意象"就成为美学本体论的基本范畴。中国古典美学将"象"作为本体之基,是通过对"象"的观察去把握"道",中国绘画创造的思维过程实质上就是意象的思维过程。本文立足从中国画的创作思维的角度探究意象的形成步骤,以达到对情和景二种基本因素构成的"意象",这一中国古典美学的审美本体做出全面的诠释。     

浅谈无障碍色彩设计

无障碍色彩设计是一个面向所有公众的设计系统,该系统的最终目标为创建无障碍可视环境,使信息尽可能准确地传达给更多的公众。本文通过提出我国在视觉信息无障碍建设方面的不足,从视觉障碍人群的类别和色彩认知特点进行归类分析,提出用无障碍色彩设计来创建视觉信息的无障碍环境。     

广告制胜的先决要素——视觉强度

视觉强度是所有诉诸视觉的艺术和设计追求的目的之一。广告是视觉艺术。若要释放这股强劲的潜能,视觉强度是视觉力量的保证。视觉强度,即对于视觉客体来说,是指对视觉主体的刺激或冲击程度;对于视觉主体来说,是指接受视觉对象刺激或冲击的强度,也称视觉感知度。一个人对不同的视觉对象产生不同的视觉感知度,而同一个视觉客体对不同人也可产生不同的冲击或刺激程度。空间与时间的差异也可引起视觉强度的差异。     

传统图形中共生现象的探究

传统设计元素与现代设计手法如何消除对峙,促进相互融合,一直是艺术设计界值得研究的问题。两者虽在表现形式上存在着一些差异,但它们的审美目的和创造性价值所传达出来的艺术信息是具有共性的,文章将传统图形中共生现象定为研究对象,探究其成因、特点、继承及影响,这将对于如何进一步尊重传统、发掘传统;如何继续深层次研究促使中国传统图形的在当代视觉传达中的应用,起到抛砖引玉的作用。     

基于运动矢量分量差的视频隐写算法

针对H.264/AVC视频压缩标准,提出基于运动矢量分量差的隐写算法。根据人眼视觉特性,筛选出人眼较不敏感的运动矢量,计算其分量差以控制嵌入操作的位置,并在选定的运动矢量分量中嵌入秘密信息。由于操作具有对称性,因此对视频质量的影响较小。理论分析和实验结果证明,该算法具有较高的载体利用率和嵌入效率,能够达到视频隐蔽通信对隐蔽性和隐写容量的要求。     

A new data fusion model for high spatial- and temporal-resolution mapping of forest disturbance based on Landsat and MODIS

Investigating the temporal and spatial pattern of landscape disturbances is an important requirement for modeling ecosystem characteristics, including understanding changes in the terrestrial carbon cycle or mapping the quality and abundance of wildlife habitats. Data from the Landsat series of satellites have been successfully applied to map a range of biophysical vegetation parameters at a 30 m spatial resolution; the Landsat 16 day revisit cycle, however, which is often extended due to cloud cover, can be a major obstacle for monitoring short term disturbances and changes in vegetation characteristics through time.The development of data fusion techniques has helped to improve the temporal resolution of fine spatial resolution data by blending observations from sensors with differing spatial and temporal characteristics. This study introduces a new data fusion model for producing synthetic imagery and the detection of changes termed Spatial Temporal Adaptive Algorithm for mapping Reflectance Change (STAARCH). The algorithm is designed to detect changes in reflectance, denoting disturbance, using Tasseled Cap transformations of both Landsat TM/ETM and MODIS reflectance data. The algorithm has been tested over a 185 × 185 km study area in west-central Alberta, Canada. Results show that STAARCH was able to identify spatial and temporal changes in the landscape with a high level of detail. The spatial accuracy of the disturbed area was 93% when compared to the validation data set, while temporal changes in the landscape were correctly estimated for 87% to 89% of instances for the total disturbed area. The change sequence derived from STAARCH was also used to produce synthetic Landsat images for the study period for each available date of MODIS imagery. Comparison to existing Landsat observations showed that the change sequence derived from STAARCH helped to improve the prediction results when compared to previously published data fusion techniques.     

基于视频三音子的双模态语料自动选取算法

为实现可视语音合成,建立符合条件的双模态语料库,提出双模态语料自动选取算法。根据视频中唇部发音特征,对已有的三音子模型归类,形成视频三音子,在其基础上从原始语料中自动选取语料,利用评估函数对原始语料中的句子打分。与其他双模态语料库相比,该语料库在覆盖率等指标上有较大改进,为实现具有真实感的可视语音合成奠定基础。     

State transformation-based dynamic visual servoing for an unmanned aerial vehicle

In this paper, we propose a visual servoing control for a quadrotor unmanned aerial vehicle (UAV) which is based on a state transformation technique. The UAV is equipped with a single downwards facing camera, and the motion control objective is the regulation of relative displacement and yaw to a stationary visual target located on the ground. The state transformation is defined by a system of partial differential equations (PDEs) which eliminate roll and pitch rate dependence in the transformed image feature kinematics. A method for computing the general solutions of these PDEs is given, and we show a particular solution reduces to an established virtual camera approach. We treat point and line cases and introduce image moment features defined in the virtual camera image plane. Robustness of the control design is improved by accounting for attitude measurement bias, and uncertainty in thrust gain, mass, and image feature depth. The asymptotic stability of the closed-loop is proven. The method is based on a simple proportional-integral-derivative (PID) structure which can be readily implemented on-board. Experimental results show improved performance relative to previous work.     

Comparison of bathymetry and seagrass mapping with hyperspectral imagery and airborne bathymetric lidar in a shallow estuarine environment

We compared hyperspectral imagery and single-wavelength airborne bathymetric light detection and ranging (lidar) for shallow water (<2 m) bathymetry and seagrass mapping. Both the bathymetric results from hyperspectral imagery and airborne bathymetric lidar reveal that the presence of a strongly reflecting benthic layer under seagrass affects the elevation estimates towards the bottom depth instead of the top of seagrass canopy. Full waveform lidar was also investigated for bathymetry and similar performance to discrete lidar was observed. A provisional classification was performed with limited ground reference samples and four supervised classifiers were applied in the study to investigate the capability of airborne bathymetric lidar and hyperspectral imagery to identify seagrass genera. The overall classification accuracy is highly variable and strongly dependent on the classification strategy used. Features from bathymetric lidar alone are not sufficient for substrate classification, while hyperspectral imagery alone showed significant capability for substrate classification with over 95% overall accuracy. The fusion of hyperspectral imagery and bathymetric lidar only marginally improved the overall accuracy of seagrass classification.     

Visualizing Waypoints‐Constrained Origin‐Destination Patterns for Massive Transportation Data

Origin‐destination (OD) pattern is a highly useful means for transportation research since it summarizes urban dynamics and human mobility. However, existing visual analytics are insufficient for certain OD analytical tasks needed in transport research. For example, transport researchers are interested in path‐related movements across congested roads, besides global patterns over the entire domain. Driven by this need, we propose waypoints‐constrained OD visual analytics, a new approach for exploring path‐related OD patterns in an urban transportation network. First, we use hashing‐based query to support interactive filtering of trajectories through user‐specified waypoints. Second, we elaborate a set of design principles and rules, and derive a novel unified visual representation called the waypoints‐constrained OD view by carefully considering the OD flow presentation, the temporal variation, spatial layout and user interaction. Finally, we demonstrate the effectiveness of our interface with two case studies and expert interviews with five transportation experts.