Abstract：The water spray strongly absorbs and scatters light in the near-infrared band. Hyperspectral data is informative and plays an important role in water spray measurement. However, the spectral characteristics of water spray is similar to background. As a result, the principal component analysis (PCA) or minimum noise fraction algorithm (MNF) can hardly classify them respectively. A joint transformation method based on maximum containing area was proposed which was derived of the above two algorithms. Firstly, PCA was used to obtain a larger area than the true area of water spray, thus most of the background information was removed. Then MNF was adopted to obtain the real area of water spray from the results of PCA. So the water spray area was extracted. Hyperspectral images of nozzle water spray at different pressures were collected in the experiments. The results show that the area of water spray can be identified and located, the spray angle and spray area decrease as the pressure increase. It is consistent with the two-phase flow characteristics of water spray.

Keywords：hyperspectral; principal component analysis; minimum noise fraction; water spray

参考文献(References)：

[1]刘士和, 梁在潮. 水利枢纽中雾化流的模拟与防范[J]. 武汉大学学报(工学版), 2001(3): 1-4, 17.

LIU S H, LIANG Z C. Prediction and prevention of atomized flow in hydroelectric engineering[J]. Engineering Journal of Wuhan University, 2001(3): 1-4, 17.

[2]王亚琼, 李勇, 孙铁军, 等. 细水雾与排烟系统共同作用下地铁车站火灾烟气蔓延规律[J]. 中国公路学报, 2021, 34(11): 225-235.

WANG Y Q, LI Y, SUN T J, et al. Analysis of suppression perform water mist system and exhaust system on subway train fires in stations[J]. China Journal of Highway and Transport, 2021, 34(11): 225-235.

[3]王潇楠, 齐鹏, 于聪伟, 等. 农药雾滴雾化沉积飘失研究进展[J]. 农药学学报, 2022, 24(5): 1065-1079.

WANG X N, QI P, YU C W, et al. Research and development of atomization, deposition and drift of pesticide droplets[J]. Chinese Journal of Pesticide Science, 2022, 24(5): 1065-1079.

[4]何晨, 毛霖, 杨仲卿, 等. 逆流喷淋浓缩塔中雾化参数对脱硫废水液滴群流动与蒸发特性的影响[J]. 中国电机工程学报, 2022, 42(7): 2588-2597.

HE C, MAO L, YANG Z Q, et al. Influence of atomization parameters in countercurrent spray concentration tower on flow and evaporation characteristics of desulfurization wastewater droplets[J]. Proceedings of the CSEE, 2022, 42(7): 2588-2597.

[5]葛宝臻, 汤海军, 魏永杰, 等. 激光粒度仪嵌入式数据采集系统的设计与实现[J]. 电子测量技术, 2007(11): 55-58.

GE B Z, TANG H J, WEI Y J, et al. Embedded laser particle size measuring system[J]. Electronic Measurement Technology, 2007(11): 55-58.

[6]陈彬, 张井超, 于庆旭, 等. 雾滴粒径测量技术及激光粒度分析仪测量不确定度评定[J]. 中国农机化学报, 2021, 42(11): 37-42.

CHEN B, ZHANG J C, YU Q X, et al. Current status and uncertainty evaluation of pesticide droplet particle size measurement technology based on laser particle size analyzer[J]. Journal of Chinese Agricultural Mechanization, 2021, 42(11): 37-42.

[7]ZHANG Y, YUAN S, GAO Y. Spatial distribution and transient evolution of sub-droplet velocity and size in ultrasonic atomization[J]. Experimental Thermal and Fluid Science, 2023, 140: 110761.

[8]BURMANN F, NOIR J, BEETSCHEN S, et al. Low-cost solutions for velocimetry in rotating and opaque fluid experiments using ultrasonic time of flight[J]. Experimental Techniques, 2021, 46(3): 429-439.

[9]魏新华, 于达志, 白敬, 等. 脉宽调制间歇喷雾变量喷施系统的静态雾量分布特性[J]. 农业工程学报, 2013, 29(5): 19-24.

WEI X H, YU D Z, BAI J, et al. Static spray deposition distribution characteristics of PWM-based intermittently spraying system[J]. Transactions of the Chinese Society of Agricultural Engineering, 2013, 29(5): 19-24.

[10]XU Z, LI C H, WANG L V. Photoacoustic tomography of water in phantoms and tissue[J]. Journal of Biomedical Optics, 2010, 15(3): 036019.

[11]ROTHMAN L S, GAMACHE R R, GOLDMAN A, et al. The HITRAN database: 1986 edition[J]. Applied Optics, 1987, 26(19): 4058-97.

[12]杨嘉葳, 刘成玉, 舒嵘, 等. 城市河网尺度的水体光谱指数适宜性分析研究[J]. 光谱学与光谱分析, 2019, 39(11): 3482-3486.

YANG J W, LIU C Y, SHU R, et al. Suitability analysis of water body spectral index in urban river network[J]. Spectroscopy and Spectral Analysis, 2019, 39(11): 3482-3486.

[13]王健, 崔天翔, 王一, 等. 高分五号可见短波红外高光谱影像云检测研究[J]. 光学学报, 2021, 41(9): 239-246.

WANG J, CUI T X, WANG Y, et al. Cloud detection for GF-5 visible-shortwave infrared advanced hyperspectral image[J]. Acta Optica Sinica, 2021, 41(9): 239-246.

[14]王瑾杰, 丁建丽, 葛翔宇, 等. 分数阶微分技术在机载高光谱数据估算土壤含水量中的应用[J]. 光谱学与光谱分析, 2022, 42(11): 3559-3567.

WANG J J, DING J L, GE X Y, et al. Application of fractional order differential technology in the estimation of soil moisture content using UAV-based hyperspectral data[J]. Spectroscopy and Spectral Analysis, 2022, 42(11): 3559-3567.

[15]WANG W, YAO X F, JI M H, et al. Spectral data treatments for impervious endmember derivation and fraction mapping from Landsat ETM+ imagery: a comparative analysis[J]. Frontiers of Earth Science, 2015, 9(2): 179-191.