Focusing azimuth-invariant bistatic synthetic aperture radar data based on a polynomial model

In this paper, a focusing approach is presented to widen the use of efficient monostatic imaging algorithms for azimuth-invariant bistatic synthetic aperture radar (SAR) data. The bistatic range history is modeled by a polynomial of azimuth time. Using this model, an analytic form of the signal spectrum in the 2D frequency domain is derived, and a simple single-valued relation between the transmitter and receive ranges is established. In this way, a lot of monostatic image formation algorithms can be extended for the bistatic SAR data, and a bistatic chirp scaling algorithm is developed as an application of the new approach. This algorithm can be used to process the azimuth-invariant bistatic configuration where the transmitter and receiver platforms are moving on parallel tracks with the same velocity. In addition, some simulation results are given to demonstrate the validity of the proposed approach.     

首发抑郁症患者海马容积的研究

目的探讨首发抑郁症患者海马容积的特点。方法采用磁共振成像(MRI)技术检测19例首发抑郁症患者和19例正常对照的海马容积。结果治疗前病例组的双侧海马绝对容积(AHV)以及相对容积(AHV/ICV)均低于正常对照组,差异有统计学意义(P<0.05);病例组海马绝对容积(AHV)与病程高度相关。病例组治疗后双侧海马绝对容积(AHV)及相对容积(AHV/ICV)较治疗前增加,且差异有统计学意义(P<0.05)。结论首发抑郁症患者海马容积变化在疾病的发病与转归过程中起着重要的作用。     

Segmentation of haustral folds and polyps on haustral folds in CT colonography using complementary geodesic distance transformation

Computer-aided detection （CAD） for CT colonography refers to a scheme that automatically detects polyps in CT images of colon. Current CAD schemes already have a relatively high sensitivity and a low false positive rate. However, misdiagnosis and missed diagnosis are still common to happen, mainly due to the existence of haustral folds （HFs）. An innovative idea of segmenting semilunar HFs from the smooth colonic wall and then using different methods to detect polyps on HFs and those on the smooth colonic wall is proposed in this paper to reduce the false positives and false negatives caused by HFs. For the polyps on HFs, a novel segmentation method is specially developed based on complementary geodesic distance transformation （CGDT）. The proposed method is tested on four different models and real CT data, The property of CGDT is proved and our method turns out to be effective for HF segmentation and polyp segmentation. The encouraging experimental results primarily show the feasibility of the proposed method and its potential to improve the detection performance of CAD schemes.     

管道外表缺陷红外无损检测和缺陷识别特征方向法

通过对表面存在缺陷的被检测管道内部通以热空气,达稳态后使用红外热像仪记录表面热特征和温度分布,据此实施红外无损检测.检测结论表明这种方法切实有效.文章首次提出了缺陷形状和尺寸识别的特征方向方法,得到一些有益结论.该方法也为实现红外故障智能诊断提供了一条技术路线.     

桥吊高压电缆井检测电子成像技术应用

采用无接触式安全监测的理念,通过在桥吊高压电缆井气密箱内部安装广角摄像头和围灯进行照明,对电缆孔内部进行检查,取得良好的效果,实现节省成本、降低劳动强度、提高工作效率的目的.     

工程类数码照片档案的收集、管理与利用

与纸质照片相比,数码照片在拍摄、传输、存储、编辑、利用等方面都具有明显优势,可为工程设计企业提供特有的档案信息服务。本文对在档案信息化背景下工程类数码照片档案的收集、归档,管理、利用的方法和途径进行了探讨。     

冲击回波主频成像在箱梁孔道压浆检测中的应用

介绍了冲击回波法检测的基本原理及其目前在土木工程中的应用情况,结合江苏省在建高速公路中,对后张法预制箱梁孔道压浆的质量检测需求,通过冲击回波法对箱梁预应力束孔管道的压浆质量进行无损检测的实例,利用冲击回波实测主频的成像,判断后张法预制箱梁孔道预应力束金属波纹管中是否存在孔隙。经过凿开验证表明,冲击回波法能准确地定性判断波纹管的位置以及预制箱梁孔道内压浆密实情况。     

红外国像处理在汽车昉撞系统中的运用

基于红外图像的视觉处理,提出了新的汽车夜视安全控制方法.通过对车载热像仪所拍摄的红外图像的一系列处理,包括图像滤噪、图像分割和图像分析,得到前方车辆的排气管的形心坐标.根据这个坐标和已知的参数,建立测距几何模型,可以实时得到本车与前车的距离.指出将这一控制识别方法可以用在汽车防撞系统中,具有一定的应用前景.     

利用红外热像仪对沥青混凝土路面施工过程中温度变异的研究

通过使用红外热像仪对沥青混凝土路面施工温度变异进行研究,分析了沥青混凝土路面在运料、卸料、摊铺及碾压(初压、复压、终压)等各项工序中温度变异现象产生的原因,从而提出减少温度变异对沥青混凝土路面影响的措施。     

红外技术在舰艇消防安全中的应用

通过分析舰艇火灾发生发展规律和特点,借鉴多起事故经验教训,确定现代舰艇消防安全升级的关键环节和技术要求.介绍红外光谱分析技术和红外热检测技术在火灾早期探测、故障异常预警、快速灭火联动等领域的应用,阐述了相关原理和方法,进行实例分析.分析表明,红外技术的应用可以有效提高舰艇在火灾探测及消防救援等方面的效能,对舰艇消防安全整体能力的提升具有重要的作用.