Cloud Detection and Centroid Extraction of Laser Footprint Image of GF-7 Satellite Laser Altimetry

The laser altimeter loaded on the GaoFen-7(GF-7)satellite is designed to record the full waveform data and footprint image,which can obtain high-precision elevation control points for stereo image.The footprint camera equipped on the GF-7 laser altimetry system can capture the energy distribution at the time of laser emission and the image of the ground object where the laser falls,which can be used to judge whether the laser is affected by the cloud.At the same time,the centroid of laser spot on the footprint image can be extracted to monitor the change of laser pointing stability.In this manuscript,a data quality analysis scheme of laser altimetry based on footprint image is presented.Firstly,the cloud detection of footprint image is realized based on deep learning.The fusion result of the model is about 5%better than that of the traditional cloud detection algorithm,which can quickly and accurately determine whether the laser spot is affected by cloud.Secondly,according to the characteristics of footprint image,a threshold constrained ellipse fitting method for extracting the centroid of laser spot is proposed to monitor the pointing stability of long-period lasers.Based on the above method,the change of laser spot centroid since GF-7 satellite was put into operation is analyzed,and the conclusions obtained have certain reference significance for the quality control of satellite laser altimetry data and the analysis of pointing angle stability.

多光谱遥感影像星上压缩影响评价

开展卫星多光谱遥感影像星上压缩影响评价,是验证卫星影像是否满足应用指标的重要内容。高分七号卫星突破了我国1∶1万立体测绘技术,可满足高精度住建应用、统计应用等。当前,仍缺少高分七号星上压缩指标论证的相关研究,因此,基于高分七号模拟多光谱影像,本文从影响影像灰度、纹理、相关性等构像质量特征和影像应用能力,包括影像分割一致性及影像分类精度两方面进行影像压缩评价,并以临朐县为例进行了验证。结果表明,对于星上JPEG-LS压缩算法提供的两种压缩比:①压缩比为3∶1时,影像灰度、纹理信息保持好;多光谱遥感影像分割后图斑总数变化率和平均图斑面积变化率绝对值不超过1%,影像分割一致性较高;影像分类后Kappa系数达0.91。②压缩比为6∶1时,单波段6∶1压缩后影像相关系数最小降低到0.891,重建影像峰值信噪比小于50,影像分类后Kappa系数为0.87。③多光谱影像宜采用3∶1压缩比。本研究可为高分七号星上压缩指标论证提供参考。

乳腺癌细胞体外摄取2-脱氧葡萄糖荧光类似物

目的 观察2-脱氧葡萄糖（2-DG）荧光类似物2-N[7-硝基苯-2-乙二酸,34羟氨基]-2-脱氧葡萄糖（2-NBDG）被高表达葡萄糖转运蛋白1（GLUT-1）的乳腺癌细胞靶向摄取的情况.方法 应用逆转录聚合酶链反应（RT-PCR）法和免疫组化法检测乳腺癌MDA-MB-231细胞GLUT-1 mRNA和蛋白的表达,采用Western blot法比较乳腺癌MDA-MB-231细胞和MCF-7细胞GLUT-1的蛋白表达量.应用2-NBDG孵育人乳腺癌MDA-MB-231细胞,采用荧光显微镜及流式细胞仪观察、分析对2-NBDG的摄取情况,比较MDA-MB-231和MCF-7细胞吸收2-NBDG量的差异.结果 RT-PCR和免疫组化检测结果显示,MDA-MB-231细胞高表达GLUT-1 Western blot检测结果进一步显示,MDA-MB-231细胞的GLUT-1表达（0.946 4±0.007）高于MCF-7（0.833±0.010）.荧光成像及流式细胞仪分析结果显示,MDA-MB-231细胞能快速摄取2-NBDG,且加入50 mmol/L D-葡萄糖后,荧光强度降低了46.0%.2-NBDG孵育乳腺癌细胞20 min后,MDA-MB-231细胞荧光强度（25.10±0.57）明显高于MCF-7细胞（10.12±0.62）.结论 2-NBDG能迅速被高表达GLUT-1的乳腺癌MDA-MB-231细胞靶向吸收.

高分辨率测绘卫星遥感影像星上压缩质量评价

针对高分七号测绘卫星模拟立体像对星上压缩是否满足测图应用需求的问题,本文从影响影像灰度、纹理、相关性等构像质量特征和DSM产品精度两方面进行影像压缩质量评价实验,开展了多种格网尺寸DSM的提取,通过比较不同压缩比下重建与原始影像生成DSM平均高程误差和高程中误差进行DSM产品精度分析。结果表明,对于星上JPEG-LS压缩算法,压缩比不大于4∶1时,压缩后影像灰度特征、纹理信息保持好,影像相关性大于0.997,重建影像峰值信噪比大于50,影像压缩质量好;随着压缩比的增加,DSM产品精度逐渐降低,压缩比不大于4∶1时,DSM高程中误差小于1 m,满足1∶10 000、1∶5 000数字高程模型高程中误差一级要求。本文相关结论可为高分七号星上压缩指标论证提供参考。