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针对织物疵点检测,将灰度共生矩阵(Gray-level Co-occurrence Matrix,GLCM)与反向投影结合起来,提出了一种基于GLCM的反向投影方法(GLCM-BP)。首先介绍了GLCM-BP的原理,然后给出了织物疵点检测流程,分析并优化了GLCM的距离d与灰度级N等参数,选择了相应的滤波与自适应阈值分割方法以检测疵点,同时给出了7种常见疵点的检测结果。最后将本文方法与GLCM方法作了检出率的比较。结果表明,提出的方法具有良好的疵点分割效果,可显著提高疵点检出率。 相似文献
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为了研究煤尘爆炸气固态残留物成分差异性及其时空分布规律,利用水平管道煤尘爆炸装置进行了煤尘爆炸实验,收集并分析了气固态残留物类别及特征。研究表明:爆炸后煤尘中灰分显著增加,挥发分和固定碳减少;爆炸前后煤尘的微观形貌特征差别明显,爆炸后煤尘颗粒表面光滑,且产生了颗粒破裂现象,部分颗粒中出现孔洞,少数颗粒呈现薄壳状,颗粒之间出现了粘结现象;煤尘爆炸气体残留物成分主要有氧气、氮气、一氧化碳、二氧化碳、甲烷、乙烯、乙烷、乙炔、丙烷等,爆源点处最低氧气浓度仅为2.52%,一氧化碳浓度达到0.38%~0.68%,距离爆源点越远,氧气浓度越高,碳氧化物气体与烃类气体浓度越低。 相似文献
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Effect of radiation-induced mean wavelength shift in optical fibers on the scale factor of an interferometric fiber optic gyroscope at a wavelength of 1300 nm
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In order to analyze the effect of wavelength-dependent radiation-induced attenuation (RIA) on the mean trans- mission wavelength in optical fiber and the scale factor of interferometric fiber optic gyroscopes (IFOGs), three types of polarization-maintaining (PM) fibers are tested by using a 60 Co γ-radiation source. The observed different mean wave- length shift (MWS) behaviors for different fibers are interpreted by color-center theory involving dose rate-dependent absorption bands in ultraviolet and visible ranges and total dose-dependent near-infrared absorption bands. To evaluate the mean wavelength variation in a fiber coil and the induced scale factor change for space-borne IFOGs under low radiation doses in a space environment, the influence of dose rate on the mean wavelength is investigated by testing four germanium (Ge) doped fibers and two germanium-phosphorus (Ge-P) codoped fibers irradiated at different dose rates. Experimental results indicate that the Ge-doped fibers show the least mean wavelength shift during irradiation and their mean wavelength of optical signal transmission in fibers will shift to a shorter wavelength in a low-dose-rate radiation environment. Finally, the change in the scale factor of IFOG resulting from the mean wavelength shift is estimated and tested, and it is found that the significant radiation-induced scale factor variation must be considered during the design of space-borne IFOGs. 相似文献
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目前,市售电话品种繁多,功能各异,电路设计千差万别,但其组成原理基本不变,主要由振铃电路、拨号电路、通话电路三部分组成,下面就三方面的故障分析及检修加以介绍。 1. 振铃电路的故障分析检修 话机不振铃是维修工作中的常见故障,通常振铃电路由集成电路构成。可通过测量集成电路的工作电压(无电压时向线路侧检查,有电压时向振铃侧检查)的方法快速排除故障。常见的集成电路有两种:一种是外带桥式整流电路的集成电路,如8204、2410、6401、2411等,另一种是自带桥式整流电路的集成电路,如2401、2418… 相似文献