一种基于双阈值红外图像增强新算法

针对红外图像的特点,提出了一种基于双阈值的红外图像增强算法.首先利用第一类灰度阈值,将图像分割成感兴趣的目标区及背景区两部分;然后根据各区域的特点,提取两部分局部直方图,并根据第二类阈值对各部分使用不同的算法进行修正,最后基于各自修正的局部直方图,在两部分灰度空间范围内进行直方图均衡化.实验表明,该算法克服了直方图均衡化对背景和噪声增强过度的问题以及基于直方图单一阈值的增强算法不具有普适性等缺点.实验证明,该算法对红外图像增强后,图像对比度和信噪比都大幅提高,具有较强的实用价值.     

A refined algorithm for multisensor image registration based on pixel migration.

Multimodality image registration via pixel migration is a powerful approach. However, it suffers from a serious problem--the global maximum on the sum of squared gradient magnitude (SSG) surface does not correspond to the correct solution of registration. To solve the problem, we partition the search space into feasible and infeasible regions. The genetic algorithm (global optimizer) is used to obtain a good initial estimate of registration parameters and followed by a fast refining with Powell's approach (local optimizer). The experimental results demonstrate that the use of this modified pixel migration algorithm on multisensor image registration is very effective.     

Reduced-rate retransmissions for spread-spectrum packet radio multimedia networks

A reduced-rate retransmission (RRR) scheme is proposed for improving the throughput performance of spread-spectrum packet radio networks. The scheme takes advantages of the available multi-rate scalable source coding techniques. It assumes that several versions of a data packet with different sizes (number of information bits) are available. The transmission of a packet starts from its full-size version. If the full-size version is not correctly received, its half-size version is used in the retransmission. If further retransmissions are needed, the quarter-size version and so on are used. The shrunk packets are transmitted either in a minislot if the processing gain is kept the same, or occupying a slot duration by increasing the processing gain proportionally. In both cases, the effective signal to interference ratio for a packet is increased. As a result, the system throughput is improved. Theoretical and numerical results are provided in this paper which illustrate the throughput improvement. Another advantage of the proposed RRR scheme is that the packet-size reduction provides finer granules for link adaptation. Therefore, it is especially suitable for multimedia applications for which codes of variable rate for the source data are available and which can tolerate gracefully degraded quality of service. The performance of the proposed scheme in fading channels is also addressed.     

电磁发射兵器用电容器的选取

本文首先从理论上论述了膜电容器的储能密度与寿命之间的关系，对国际电容器制造水平和趋势进行了分析，提出采用干式金属化膜电容器作为储能元件。最后，根据电磁发射兵器整体寿命配合原则，提出高储能密度脉冲电容器的合理寿命指标。     

推进农村通信和信息化发展的若干建议

农村地区的通信和互联网建设,是全面建设小康社会的重要基础设施之一,是一项艰巨、繁重的任务.信息产业部制定的不同时期的电信发展目标规划,具有求实性、可操作性.思前想后,各级政府的政策支持和电信运营企业尽责参与,仍是推进农村通信和农村信息化快速发展之路.然而,在电信普遍服务基金渠道、农村通信设备选用、农村信息化模式、地域目标规划等方面尚需论证落实,这是稳步实现电信小康目标的保障.     

模糊层次分析法在腐蚀影响因素分析中的应用

结合国内外对碳钢CO2腐蚀影响因素的研究成果,采用模糊层次分析法对影响输油管道 CO2腐蚀的因素进行定量分析,明确界定出这些因素对二氧化碳腐蚀影响的相对重要性(权重),为后续制定经济有效的管道内腐蚀防护措施提供了客观依据。     

小型汽油发电机供电时整流电源工作不稳定情况分析

本文通过对小功率汽油发电机组对高频开关电源供电时出现的不稳定现象进行分析,提出了可行的改造及解决方案.     

具有控制项的限定记忆卡尔曼滤波器

在已有的限定记忆卡尔曼滤波器的基础上 ,将确定性先验信息作为控制项加以应用 ,推导出了完整的限定记忆卡尔曼滤波公式 ,从而在记忆长度确定的情况下 ,有效地减小了模型不准的误差 ,降低了滤波总误差。仿真同样表明了该方法的有效性     

氨精制装置运行问题分析及改造措施

通过分析中国石油兰州石化分公司炼油厂氨精制装置存在的运行问题,提出了相应的改造措施,包括在分凝器脱液管线上新增隔离阀门、更换三级冷凝冷却器、更换氨压缩机及采用低温结晶脱硫工艺等。改造后装置运行结果表明:三级分凝器出口温度由70℃降至小于35℃,压缩机吸气量由5 m3/m in提高至74 m3/m in,原料酸性水中硫化氢质量分数下降45.5%,氨质量分数下降55.5%,净化水合格率达100%,氨精制塔塔顶温度下降5~20℃,液氨中氨质量分数由97.05%上升至99.60%,液氨产量达0.125 t/h,实现了装置的长周期运行。     

石油沥青60℃动力粘度测定影响因素的探讨

粘度是表征沥青稠度的一个重要指标。通过论述石油沥青粘度测定法(真空毛细管法)中毛细管的选择、温度、真空度、取样量等对试验结果的影响及试验过程中的其它注意事项,表明了在测定石油沥青的60℃动力粘度时,必须严格按照试验方法的要求进行测定,以保证试验结果的准确性。