Abstract Stimuli Associated With Threat Through Conditioning Cannot Be Detected Preattentively.

Studies of anxiety suggest that threat stimuli can be identified preattentively, but this conclusion is questionable because of possible low-level perceptual confounds. Two experiments used visual search tasks in which abstract shapes were conditioned to carry neutral or negative valence. Experiment 1 found generally faster responses to threat-associated abstract stimuli but no evidence that they were detected preattentively, irrespective of trait anxiety level. A similar pattern was found in Experiment 2, in which individuals high in snake or spider fear showed no evidence of preattentive detection of abstract stimuli associated with their feared object. In contrast, implicit behavioral measures showed significant effects of conditioning, demonstrating that targets associated with threat were negatively evaluated in these experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Velocity-Guided Tracking of Deformable Contours in Three Dimensional Space

This paper presents a 3D active contour model for boundary detection and tracking of non-rigid objects, which applies stereo vision and motion analysis to the class of energy-minimizing deformable contour models, known as snakes. The proposed contour evolves in three-dimensional space in reaction to a 3D potential function, which is derived by projecting the contour onto the 2D stereo images. The potential function is augmented by a kinetic term, which is related to the velocity field along the contour. This term is used to guide the inter-image contour displacement. The incorporation of inter-frame velocity estimates in the tracking algorithm is especially important for contours which evolve in 3D space, where the added freedom of motion can easily result in loss of tracking. The proposed scheme incorporates local velocity information seamlessly in the snake model, with little computational overhead, and does not require exogenous computation of the optical flow or related quantities in each image. The resulting algorithm is shown to provide good tracking performance with only one iteration per frame, which provides a considerable advantage for real time operation.     

Segmentation of the carotid intima-media region in B-mode ultrasound images

This paper proposes a new approach for the segmentation of both near-end and far-end intima-media regions of the common carotid artery in ultrasound images. The method requires minimal user interaction and is able to segment the near-end wall in arteries with large, hypoechogenic and irregular plaques, issues usually not considered previously due to the increased segmentation difficulty.     

微管吸吮下细胞视频图像分析系统设计与实现

为了理解力学刺激和细胞生长的关系,有助于理解细胞病变的机理,科学工作者采用微管吸吮实验,计算不同时刻下细胞在力学刺激下的变形参数。为了提高量化精度,减低人工计算的繁琐程度,提出了＂细胞视频图像分析系统＂的主要功能、总体设计框架和基本算法,并对视频图像预处理、分割算法进行了详细地阐述。实验结果表明,这是一款可操作性强、精度高、便捷实用的软件自动化测量系统。     

基于Squeezenet模型的蛇类图像识别

随着人类活动范围的不断扩张,生态环境的恶化,蛇类的生存环境受到威胁。为实现对蛇类的准确识别,辅助蛇类研究者对蛇类的识别与保护,通过对现有的解决方案进行分析,提出采用迁移学习方法对10种蛇类进行训练识别。首先对现有数据集进行数据增强,从而让训练模型更好地收敛,采用基于Squeezenet模型具有更好的识别率,识别率达到了85.71%,效果良好。并对训练好的模型进行加载,网络模型识别耗时2.69s,有着更好实时性,同时还能保证识别精度,节省硬件资源,提升了模型的可移植性。     

Differential effects of courtship and mating on receptivity and brain metabolism in female red-sided garter snakes (Thamnophis sirtalis pareitalis).

In the female red-sided garter snake (Thamnophis sirtalis parietalis), the loss of receptivity following intromission during mating can be prevented by injection of a local anesthetic (tetracaine) in the cloacal region prior to courtship and mating. Females that were courted and then mated had significantly higher uptake of radio-labeled [1?C]2-fluoro-2-deoxyglucose (2-DG) in the preoptic area (25%) and significantly lower uptake in the ventromedial hypothalamus (-20%) compared with females that were courted but not mated. Tetracaine-treated females had accumulation patterns similar to courted but unmated females and to females exposed only to other females. These results suggest that in the female red-sided garter snake, sensory input from the cloaca during mating alters patterns of metabolism in those brain areas most often associated with female sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The background primal sketch: An approach for tracking moving objects

In this paper we present an algorithm that integrates spatial and temporal information for the tracking of moving nonrigid objects. In addition, we obtain outlines of the moving objects.Three basic ingredients are employed in the proposed algorithm, namely, the background primal sketch, the threshold, and outlier maps. The background primal sketch is an edge map of the background without moving objects. If the background primal sketch is known, then edges of moving objects can be determined by comparing the edge map of the input image with the background primal sketch. A moving edge point is modeled as an outlier, that is, a pixel with an edge value differing from the background edge value in the background primal sketch by an amount larger than the threshold in the threshold map at the same physical location. The map that contains all the outliers is called the outlier map. In this paper we present techniques based on robust statistics for determining the background primal sketch, the threshold, and outlier maps.In an ideal situation the outlier map would contain the complete outlines of the moving objects. In practice, the outliers do not form closed contours. The final step of the algorithm employs an edge-guided morphological approach to generate closed outlines of the moving objects. The proposed approach has been tested on sequences of moving human blood cells (neutrophil) as well as of human body motion with encouraging results.     

直线Snakes及其在建筑物提取中的应用

在直线检测的基础上，将传统Snakes的基本元素由像素点变更为直线段，提出了一种直线Snakes算法．该方法利用中层图像处理技术对杂乱无章的底层图像信息的初步组织和解释功能，提高了Snakes的计算效率，增强了Snakes的稳定性鲁棒性，并在建筑物屋顶轮廓提取中提出了成功的应用．     

Visual search with biological threat stimuli: Accuracy, reaction times, and heart rate changes.

Twenty-four participants were given a visual search task of deciding whether all the pictures in 3×3 search arrays contained a target picture from a deviant category, and heart rate was measured. The categories were snakes, spiders, flowers, and mushrooms. Shorter reaction times (RTs) were observed for fear-relevant (snake and spider) targets rather than for fear-irrelevant/neutral (flower and mushroom) targets. This difference was most pronounced for the participants presented with a gray-scale version of the search arrays. The 1st interbeat interval (IBI), after the search array onset, showed an effect of the target, whereas the 2nd IBI also showed an effect of the distractors. The results suggest that controlled processing of the task operates together with automatic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some Remarks on the Equivalence between 2D and 3D Classical Snakes and Geodesic Active Contours

Recently, Caselles et al. have shown the equivalence between a classical snake problem of Kass et al. and a geodesic active contour model. The PDE derived from the geodesic problem gives an evolution equation for active contours which is very powerfull for image segmentation since changes of topology are allowed using the level set implementation. However in Caselles' paper the equivalence with classical snake is only shown for 2D images and 1D curves, by using concepts of Hamiltonian theory which have no meanings for active surfaces. This paper propose to examine the notion of equivalence and to revisite Caselles et al. arguments. Then a notion equivalence is introduced and shown for classical snakes and geodesic active contours in the 2D (active contour) and 3D (active surface) case.