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对薄膜测厚系统进行了详尽剖析,从整体上论述了膜厚测量系统,研究了测厚系统中薄膜测厚仪的关键硬件电路,对薄膜测厚仪的软件流程进行了离散设计。以AVR单片机为核心处理器进行了数据采集和处理,设计并生产出了在线式光学薄膜厚度测量与监控系统。通过与实际膜厚进行对比实验,验证了薄膜测厚系统具有高精度、高稳定性和高可靠性,可应用于实际工业生产。 相似文献
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以往的超声测厚方法对于厚度1mm以下的薄板测量是很难处理的,特别是对于厚度变化部分的高精度测证研究较少。本文提出一种超声波厚度共振测厚法,可精确测量1mm以下薄板的厚度及厚度变化。测量原理是将超声波垂直射入被测薄板,板中超声波将在板的两界面发生反复反射,改变超声波频率,当板的厚度d与超声波的波长λ有d=nλ/2(n是整数)关系时,板中形成驻波、产生共振。其共振频率f_n可以表示为f_n=v/(2d)·n,v是声速。共振频率由板的厚度和超声波的声速决定。进行厚度变化测量时,是测量共振频率的变化。板的厚度变化△d时,共振频率变 相似文献
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超声波反射法应用于高炉炉墙测厚时,高炉内部环境高温高噪声的特点,造成超声回波信号被噪声湮没的问题;针对这一问题,研究了超声波在金属介质中传播的机理,分析了超声回波信号信噪比下降的原因以及实验数据时域和频域的特征,设计改进了高炉炉墙测厚的超声波发射电路和信号调理电路;采用加热炉模拟高炉200~1 000 ℃温度环境,对直径40 mm、长度1.2 m的铁棒进行测厚实验;经实测,改进的发射电路发射的超声信号强度增大,回波处理电路处理后超声回波信号信噪比明显提高、峰值清晰可辩,解决了噪声湮没回波信号的问题,提高了高炉炉墙测厚的测量精度,对高炉的高产、顺产和延长炉龄具有实际意义。 相似文献
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基于高速波形数字化实现高精度时间测量是核与粒子物理实验读出电子学中的研究热点。本工作针对高精度时间测量的需求基于实验室自主研发的开关电容阵列(Switched Capacitor Array, SCA)专用集成电路(Application Specific Integrated Circuit,ASIC)开展16通道集成的时间测量电子学原型的设计,输入信号经过SCA采样和量化后传输至现场可编程逻辑阵列(Field Programmable Gate Array, FPGA),在FPGA中进行误差修正、时间内插和数字甄别提取出时间信息。目前已在实验室环境下完成此电子学的时间精度测试,测试结果表明,此电子学可以实现好于10 ps RMS(Root Mean Square)的时间精度。 相似文献
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基于区域特性量测的图像融合方法 总被引:1,自引:0,他引:1
在图像融合过程中,融合规则及融合算子的选择对于融合的质量至关重要,也是图像融合中至今尚未很好解决的难点问题。本文给出了一种新的融合规则——基于区域特性量测的融合规则,即在对某一分解层图像进行融合处理时,为了确定融合后的像素不仅要考虑参加融合图像中对应的各像素,而且要考虑参加融合像素的局部领域。 相似文献
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基于目前国内规模最大的激光驱动器——“神光Ⅱ”八路基频光已经实现功率平衡运行,通过改变其中若干路三倍频系统各调谐量的偏离,对输出三倍频波形进行束与束之间的横向对比研究.研究发现,对于Ⅱ类-Ⅱ类偏振失配三倍频系统,在影响转换效率的三个调谐量中,偏振分配角失配Δθp对三倍频波形影响最大;在入射基频功率密度约为1.0GW/cm2情况下,当三倍频系统三个调谐量都处在最佳匹配时,三倍频波形半峰全宽τ最小.研究工作为最终实现“神光Ⅱ”八路光束三倍频功率平衡输出提供了晶体调试
关键词:
三倍频
时间波形
功率平衡 相似文献
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Moisturizing creams and lotions are commonly used in daily life for beauty and treatment of different skin conditions such as dryness and wrinkling, and ultrasound stimulation has been used to enhance the delivery of ingredients into skin. However, there is a lack of convenient methods to study the effect of ultrasound stimulation on lotion absorption by skin in vivo. Ultrasound biomicroscopy was adopted as a viable tool in this study to investigate the effectiveness of ultrasound stimulation on the enhancement of lotion delivery into skin. The forearm skin of 10 male and 10 female young subjects was tested at three different sites, including two lotion treatment sites with (Ultrasound Equipment – UE ON) and without (UE OFF) ultrasound stimulation and a control site without any lotion treatment. 1 MHz ultrasound with a duty cycle of 1.7%, a spatial peak temporal peak pressure of 195 kPa and an average power of 0.43 W was used for the stimulation. The skin thickness before, immediately after (0 min), and 15 and 30 min after the treatment was measured by an ultrasound biomicroscopic system (55 MHz). It was found that the skin thickness significantly increased immediately after the lotion treatment for both UE ON (from 1.379 ± 0.187 mm to 1.466 ± 0.182 mm, p < 0.001) and UE OFF (from 1.396 ± 0.193 mm to 1.430 ± 0.194 mm, p < 0.001) groups. Further comparison between the two groups revealed that the skin thickness increase of UE ON group was significantly larger than that of UE OFF group (6.5 ± 2.4% vs. 2.5 ± 1.3%, p < 0.001). Furthermore, it was disclosed that the enhancement of lotion delivery by ultrasound stimulation was more effective for the female subjects than the male subjects (7.6 ± 2.3% vs. 5.4 ± 2.0% immediately after treatment, p = 0.017). In conclusion, this study demonstrated that ultrasound biomicroscopy was a feasible method for studying the effectiveness of lotion treatment in vivo, and ultrasound stimulation was effective to enhance the rate of lotion absorption into skin. 相似文献
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Information fusion method for ocular aberrations measurement based on subjective visual compensation
The human eye is an imperfect refractive system which not only has defocus and astigmatism, but also has spherical aberration, coma and anomalistic high-order aberrations, all of which have certain influence on the imaging quality of retina. What's worse, aberration is further enlarged as a result of mydriasis in dark field and weak light, thus making the vision performance of human eyes far below diffraction limitation. Further research revealed that human eye visual imaging is not only connected with refractive system, but also is closely related to the subjective judgment of human brain and the process of neural system. In order to overcome the deficiencies, wave-front aberration measurement method and system that has subjective visual compensation is proposed and conducted in combination with objective measurement, which ensures more accurate and realistic measuring results. The experimental data revealed that wave-front aberration obtained from subjective visual compensation measuring method is smaller than objective measurement, which is the result of subjects’ adaptive correction when watching sighting targets. In addition, when subjects are watching different sighting targets, the fluctuation value of wavefront aberration is small. Therefore, it is concluded that subjective visual compensation measuring method contributes to aberration measuring improvement and obtains results match with the realistic state by taking into consideration the actual condition of human eyes when watching targets. Hopefully, these discoveries will be of positive and beneficial value to the determination of human eye aberration treatment. 相似文献
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一种基于边缘的曲波变换图像融合方法 总被引:3,自引:0,他引:3
提出了一种新的图像融合方法。采用Canny边缘检测方法,并结合曲波变换算法,确定图像边缘位置。针对曲波分解的不同频率域,对高频信息依据其是否为边缘点采用不同的融合策略,对低频信息利用平均法进行融合,最后进行重构得到融合结果。对该方法得到的实验结果进行主客观评价和对比表明,提出的算法在抑制噪声的同时,能有效地突出边缘细节,具有更好的视觉效果。 相似文献
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提出了一种利用DCT变换和小波变换的特征层图像融合算法.其基本思想是先对多幅源图像进行分块DCT变换,选取较大方差对应的变换系数,将图像压缩为原图像大小的1/4,保留系数的对应坐标作为提取信息时的密钥;其次将经处理后的DCT系数直接作为小波变换的分解系数,经小波逆变换后得到融合信息.实验结果表明,该算法实现了多幅不同大小图像的融合,同时单一密钥只能提取单一图像.
关键词:
图像融合
小波变换
离散余弦变换
编码 相似文献
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针对红外偏振图像可以较好地抑制背景噪声,对目标边缘信息比较敏感的特点,提出一种基于小波变换的红外偏振融合算法,它主要用于红外辐射强度图像和偏振度图像融合,增加图像的信息量。首先采用小波变换对参与融合的每幅图像分别进行各尺度分解,得到各尺度小波系数,然后针对不同尺度小波系数,采用邻域平均梯度为判据进行融合,得到融合后的各尺度小波系数,最后通过小波逆变换进行图像重构,得到融合图像。融合前后的图像对比表明融合图像在保留辐射强度图像的清晰度的同时,突出了目标的边缘、轮廓信息。相对于辐射强度图像,融合图像的梯度均值提高了112%,相对于偏振度图像,融合图像的标准差提高了151%,信息熵提高了38%。 相似文献
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A method is described of measuring the thickness of thin films by using white light fringes obtained in a double pass Michelson interferometer. The method is suitable for the determination of thickness ranging from 15 nm to 2500 nm. 相似文献
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为克服非采样Contourlet变换中金字塔分解的不足,首先在提升小波变换的基础上,通过取消其奇偶分裂环节得到具有平移不变性的非采样提升小波变换,然后用此变换来取代非采样Contourlet变换中的金字塔分解,得到新的非采样提升小波-Contourlet变换。将此变换与一定的融合规则相结合,提出了一种基于非采样提升小波-Contourlet变换的图像融合算法。实验表明,该算法相对于非采样Contourlet变换能从源图像中提取更多有用信息注入到融合图像中,可得到更高性能的融合图像。 相似文献