CMYKIR红外防伪图像技术

印刷油墨在近红外波长区域的响应是不同的,不能用CIELAB、sRGB或HSB这些基于可见光颜色理论建立的色彩系统参数来描述。用来描述人眼接收图像的RGB加色呈色系统与可以覆盖几乎全部可见光谱内印刷品的C_0M_0Y_0色料减色呈色系统相对应。加入对红外波谱有着极佳响应的黑色油墨,配上CMY减色油墨,就可以使每一种色调有着无数种配比方法。CMYK印刷油墨的特性是得到独立图像两种外观表现响应算法的基础,一种是日光下的图像外观,一种是红外光下的图像外观。预设算法基于两个图像,即原始图像X_0和在蒙版F基础上生成的印刷图像X。此举的目的是通过对红外图像检测实现文件防伪。在仪器帮助下,700～1000nm波长范围内的图像元素为可见,使只用原色油墨印刷图像进行信息选择成为可能。每个原色油墨的特性用于向为生成红外图像而进行的RGB/CMYK图像分离过程中引入新的标准。这种图像分离称为CMYKIR图像分离,并用其来设计红外响应图像的油墨用量,这种红外响应包括IR效果的产生和消除。CMYKIR印刷的目的在于,引入可见光谱下无法观察到的红外图像。

Curve interpolation model for visualising disjointed neural elements

Neuron cell are built from a myriad of axon and denddte structures. It transmits electrochemical signals between the brain and the nervous system. Three-dimensional visualization of neuron structure could help to facilitate deeper understanding of neuron and its models. An accurate neuron model could aid understanding of brain＇s functionalities, diagnosis and knowledge of entire nervous system. Existing neuron models have been found to be defective in the aspect of realism. Whereas in the actual biological neuron, there is continuous growth as the soma extending to the axon and the dendrite; but, the current neuron visualization models present it as disjointed segments that has greatly mediated effective realism. In this research, a new reconstruction model comprising of the Bounding Cylinder, Curve Interpolation and Gouraud Shading is proposed to visualize neuron model in order to improve realism. The reconstructed model is used to design algorithms for generating neuron branching from neuron SWC data. The Bounding Cylinder and Curve Interpolation methods are used to improve the connected segments of the neuron model using a series of cascaded cylinders along the neuron＇s connection path. Three control points are proposed between two adjacent neuron segments. Finally, the model is rendered with Gouraud Shading for smoothening of the model surface. This produce a near-perfection model of the natural neurons with attended realism. The model is validated by a group of bioinformatics analysts＇ responses to a predefined survey. The result shows about 82% acceptance and satisfaction rate.

Solid model edit distance: a multi-application and multi-level schema for CAD model retrieval

We present the solid model edit distance(SMED),a powerful and flexible paradigm for exploiting shape similarities amongst CAD models.It is designed to measure the magnitude of distortions between two CAD models in boundary representation(B-rep).We give the formal definition by analogy with graph edit distance,one of the most popular graph matching methods.To avoid the expensive computational cost potentially caused by exact computation,an approximate procedure based on the alignment of local structure sets is provided in addition.In order to verify the flexibility,we make intensive investigations on three typical applications in manufacturing industry,and describe how our method can be adapted to meet the various requirements.Furthermore,a multilevel method is proposed to make further improvements of the presented algorithm on both effectiveness and efficiency,in which the models are hierarchically segmented into the configurations of features.Experiment results show that SMED serves as a reasonable measurement of shape similarity for CAD models,and the proposed approach provides remarkable performance on a real-world CAD model database.

Caustics of developable surfaces

While considering a mirror and light rays coming either from a point source or from infinity,the reflected light rays may have an envelope,called a caustic curve.In this paper,we study developable surfaces as mirrors.These caustic surfaces,described in a closed form,are also developable surfaces of the same type as the original mirror surface.We provide efficient,algorithmic computation to find the caustic surface of each of the three types of developable surfaces(cone,cylinder,and tangent surface of a spatial curve).We also provide a potential application of the results in contemporary free-form architecture design.

Identification of altitude profiles in 3D geovisualizations:the role of interaction and spatial abilities

Three-dimensional geovisualizations are currently pushed both by technological development and by the demands of experts in various applied areas.In the presented empirical study,we compared the features of real 3D(stereoscopic)versus pseudo 3D(monoscopic)geovisualizations in static and interactive digital elevation models.We tested 39 high-school students in their ability to identify the correct terrain profile from digital elevation models.Students’performance was recorded and further analysed with respect to their spatial abilities,which were measured by a psychological mental rotation test and think aloud protocol.The results of the study indicated that the influence of the type of 3D visualization(monoscopic/stereoscopic)on the performance of the users is not clear,the level of navigational interactivity has significant influence on the usability of a particular 3D visualization,and finally no influences of the spatial abilities on the performance of the user within the 3D environment were identified.