Green vegetation extraction based on visible light image of UAV
ZHOU Tao1, HU Zhen-qi1,2, HAN Jia-zheng1, ZHANG Hao1
1. School of Environmental and Spatial Informatics, China University of Mining and Technology, Xuzhou 221100, China; 2. Institute of Land Reclamation and Ecological Restoration, China University of Mining and Technology(Beijing), Beijing 100083, China
Abstract:Using visible light images taken by unmanned aerial vehicle (UAV) as data source, a new green vegetation index named as Difference Enhanced Vegetation Index (DEVI) was proposed based on the analysis of healthy green vegetation spectral characteristics and the differences of pixel values among different bands of typical ground objects in visible light images of UAVs. DEVI utilized the information of red, green and blue visible bands, which can not only eliminate the interference caused by the difference of pixel values in a single band of green wave of different ground objects, but also enhance the characteristic that the reflectivity of green wave of green vegetation is greater than that of red and blue bands. This new index and 8 other common visible light vegetation indexes were used to extract the green vegetation by the threshold method in the study area, and then the support-vector machine (SVM)-based supervised classification method and the ground truth area of interest (ROIs) were used to evaluate the extraction accuracy. The results showed that the extraction accuracy of DEVI was significantly better than the other eight vegetation indexes. When the threshold method of image histogram visual detection was adopted, the overall accuracy was 98.98%, the Kappa coefficient was 0.9791, and the relative error was 1/83. Meanwhile, the gray image histogram of vegetation index calculated by DEVI had a good bimodal shape, which could quickly determine the threshold value, and the threshold value was generally located between 0.9 and 1. To verify whether DEVI has good applicability and reliability, this study chose three typical areas to conduct the feasibility verification analysis:area with high vegetation coverage, area with dense regions of buildings, and area with discretely distributed vegetation. The results showed that the green vegetation information in regions with dense buildings and discretely distributed vegetation could be extracted with high precisions by DEVI. The overall accuracy was 98.42% and 98.56%, the Kappa coefficient was 0.9610 and 0.9635, and the relative error was 1/125 and 1/91, respectively. However, the extraction accuracy in areas with high vegetation coverages was slightly less accurate with the overall accuracy of 97.40%, a Kappa coefficient of 0.9371, and a relative error of 1/53. Therefore, the new DEVI could extract the green vegetation information from UAV visible light images in typical vegetation covered areas in an effective, high-precision and low-cost way. Therefore, DEVI is a feasible method for the green vegetation monitoring research in terrestrial ecosystems.
周涛, 胡振琪, 韩佳政, 张浩. 基于无人机可见光影像的绿色植被提取[J]. 中国环境科学, 2021, 41(5): 2380-2390.
ZHOU Tao, HU Zhen-qi, HAN Jia-zheng, ZHANG Hao. Green vegetation extraction based on visible light image of UAV. CHINA ENVIRONMENTAL SCIENCECE, 2021, 41(5): 2380-2390.
高井祥.数字测图原理与方法[M]. 徐州:中国矿业大学出版社, 2015:278-279. Gao J X. Principles and methods of digital mapping[M]. Xuzhou:China university of Mining and Technology Press, 2015:278-279.
[2]
王利民,刘佳,杨玲波,等.基于无人机影像的农情遥感监测应用[J]. 农业工程学报, 2013,29(18):136-145. Wang L M, Liu J, Yang L B, et al. Applications of unmanned aerial vehicle images on agricultural remote sensing monitoring[J]. Transactions of the Chinese Society of Agricultural Engineering, 2013,29(18):136-145.
[3]
李宗南,陈仲新,王利民,等.基于小型无人机遥感的玉米倒伏面积提取[J]. 农业工程学报, 2014,30(19):207-213. Li Z N, Chen Z X, Wang L M, et al. Area extraction of maize lodging based on remote sensing by small unmanned aerial vehicle[J]. Transactions of the Chinese Society of Agricultural Engineering, 2014, 30(19):207-213.
[4]
李冰,刘镕源,刘素红,等.基于低空无人机遥感的冬小麦覆盖度变化监测[J]. 农业工程学报, 2012,28(13):160-165. Li B, Liu R Y, Liu S H, et al. Monitoring vegetation coverage variation of winter wheat by low-altitude UAV remote sensing system[J]. Transactions of the Chinese Society of Agricultural Engineering, 2012, 28(13):160-165.
[5]
高林,杨贵军,于海洋,等.基于无人机高光谱遥感的冬小麦叶面积指数反演[J]. 农业工程学报, 2016,32(22):113-120. Gao L, Yang G J, Yu H Y, et al. Retrieving winter wheat leaf area index based on unmanned aerial vehicle hyperspectral remoter sensing[J]. Transactions of the Chinese Society of Agricultural Engineering, 2016,32(22):113-120.
[6]
韩文霆,李广,苑梦婵,等.基于无人机遥感技术的玉米种植信息提取方法研究[J]. 农业机械学报, 2017,48(1):139-147. Han W T, Li G, Yuan M C, et al. Extraction method of maize planting information based on UAV remote sensing technology[J]. Transactions of the Chinese Society for Agricultural Machinery, 2017, 48(1):139-147.
[7]
张园,陶萍,梁世祥,等.无人机遥感在森林资源调查中的应用[J]. 西南林业大学学报, 2011,31(3):49-53. Zhang Y, Tao P, Liang S X, et al. Research on application of UAV RS techniques in forest inventories[J]. Journal of Southwest Forestry university, 2011,31(3):49-53.
[8]
杨坤,赵艳玲,张建勇,等.利用无人机高分辨率影像进行树木高度提取[J]. 北京林业大学学报, 2017,39(8):17-23. Yang K, Zhao Y L, Zhang J Y, et al. Tree height extraction using high-resolution imagery acquired from an unmanned aerial vehicle (UAV)[J]. Journal of Beijing Forestry University, 2017,39(8):17-23.
[9]
史洁青,冯仲科,刘金成.基于无人机遥感影像的高精度森林资源调查系统设计与试验[J]. 农业工程学报, 2017,33(11):82-90. Shi J Q, Feng Z K, Liu J C. Design and experiment of high precision forest resource investigation system based on UAV remote sensing images[J]. Transactions of the Chinese Society of Agricultural Engineering, 2017,33(11):82-90.
[10]
Sanada Y, Urabe Y, Sasaki M, et al. Evaluation of ecological half-life of dose rate based on airborne radiation monitoring following the Fukushima Dai-ichi nuclear power plant accident[J]. Journal of Environmental Radioactivity, 2018,192(12):417-425.
[11]
Schofield G, Esteban N, Katselidis K A, et al. Drones for research on sea turtles and other marine vertebrates-A review[J]. Biological Conservation, 2019,238:108214.
[12]
肖武,任河,闫皓月,等.基于无人机遥感的高潜水位采煤沉陷湿地植被分类[J]. 农业机械学报, 2019,50(2):177-186. Xiao W, Ren H, Yan H Y, et al. Vegetation classification by using UAV remote Sensing in coal mining subsidence wetland with high ground-water level[J]. Transactions of the Chinese Society for Agricultural Machinery, 2019,50(2):177-186.
[13]
肖武,赵艳玲,胡振琪,等.利用无人机遥感反演高潜水位矿区沉陷地玉米叶绿素含量[J]. 煤炭学报, 2019,44(1):295-306. Xiao W, Zhao Y L, Hu Z Q, et al. Identify maize chlorophyll impacted by coal mining subsidence in high groundwater table area based on UAV remote sensing[J]. Journal of China Coal Society, 2019,44(1):295-306.
[14]
徐岩,胡振琪,陈景平,等.基于无人机遥感的开采沉陷耕地质量评价及复垦建议[J]. 金属矿山, 2019,(3):173-181. Xu Y, Hu Z Q, Chen J P, et al. Quality evaluation of farmland and land reclamation suggestions of mining subsidence area based on unmanned aerial vehicle remote sensing[J]. Metal Mine, 2019,(3):173-181.
[15]
肖武,胡振琪,张建勇,等.无人机遥感在矿区监测与土地复垦中的应用前景[J]. 中国矿业, 2017,26(6):71-78. Xiao W, Hu Z Q, Zhang J Y, et al. The status and prospect of UAV remote sensing in mine monitoring and land reclamation[J]. China Mining Magazine, 2017,26(6):71-78.
[16]
张超,陨文聚,高露露,等.土地整治遥感监测研究进展分析[J]. 农业机械学报, 2019,50(1):1-22. Zhang C, Yun W J, Gao L L, et al. Analysis on research progress of remote sensing monitoring of land consolidation[J]. Transactions of the Chinese Society for Agricultural Machinery, 2019,50(1):1-22.
[17]
秦伟,朱清科,张学霞,等.植被覆盖度及其测算方法研究进展[J]. 西北农林科技大学学报(自然科学版), 2006,34(9):163-170. Qin W, Zhu Q K, Zhang X X, et al. Review of vegetation covering and its measuring and calculating method[J]. Journal of Northwest A & F University (Nature Science Edition), 2006,34(9):163:170.
[18]
陈鹏,冯海宽,李长春,等.无人机影像光谱和纹理融合信息估算马铃薯叶片叶绿素含量[J]. 农业工程学报, 2019,35(11):63-74. Chen P, Feng H K, Li C C, et al. Estimation of chlorophyll content in potato using fusion of texture and spectral features derived from UAV multispectral image[J]. Transactions of the Chinese Society of Agricultural Engineering, 2019,35(11):63-74.
[19]
Jin X L, Li Z H, Clement Atzberger. Editorial for the special issue "Estimation of Crop Phenotyping Traits using Unmanned Ground Vehicle and Unmanned Aerial Vehicle Imagery"[J]. Remote Sensing, 2020,12(6):940.
[20]
田振坤,傅莺莺,刘素红,等.基于无人机低空遥感的农作物快速分类方法[J]. 农业工程学报, 2013,29(7):109-116. Tian Z K, Fu Y Y, Liu S H, et al. Rapid crops classification based on UAV low-altitude remote sensing[J]. Transactions of the Chinese Society of Agricultural Engineering, 2013,29(7):109-116.
[21]
Zhang X L, Zhang F, Qi Y X, et al. New research methods for vegetation information extraction based on visible light remote sensing images from an unmanned aerial vehicle (UAV)[J]. International Journal of Applied Earth Observation and Geoinformation, 2019,78:215-226.
[22]
汪小钦,王苗苗,王绍强,等.基于可见光波段无人机遥感的植被信息提取[J]. 农业工程学报, 2015,31(5):152-157. Wang X Q, Wang M M, Wang S Q, et al. Extraction of vegetation information from visible unmanned aerial vehicle images[J]. Transactions of the Chinese Society of Agricultural Engineering, 2015, 31(5):152-159.
[23]
高永刚,林悦欢,温小乐,等.基于无人机影像的可见光波段植被信息识别[J]. 农业工程学报, 2020,36(3):178-189. Gao Y G, Lin Y H, Wen X L, et al. Vegetation information recognition in visible band based on UAV images[J]. Transactions of the Chinese Society of Agricultural Engineering, 2020,36(3):178-189.
[24]
王美琪,杨建英,孙永康,等.废弃矿山植被覆盖度无人机遥感快速提取技术[J]. 中国水土保持科学, 2020,18(2):130-139. Wang M Q, Yang J Y, Sun Y K, et al. Remote sensing rapid extraction technology for abandoned mine vegetation coverage via UAV[J]. Science of Soil and Water Conservation, 2020,18(2):130-139.
[25]
Gennaro S F D, Matese A. Evaluation of novel precision viticulture tool for canopy biomass estimation and missing plant detection based on 2.5D and 3D approaches using RGB images acquired by UAV platform[J]. Plant Methods, 2020,16(1):233-129.
[26]
Jiang X P, Gao Z Q, Zhang Q C, et al. Remote sensing methods for biomass estimation of green algae attached to nursery-nets and raft rope[J]. Marine Pollution Bulletin, 2020,150:110678.
[27]
Li B, Xu X M, Zhang L, et al. Above-ground biomass estimation and yield prediction in potato by using UAV-based RGB and hyperspectral imaging[J]. ISPRS Journal of Photogrammetry and Remote Sensing, 2020,162:161-172.
[28]
Woebbecke D M, Meyer G E, Von Bargen K, et al. Color indices for weed identification under various soil, residue, and lighting conditions[J]. Transactions of the American Society of Agricultural Engineers, 1995,38(1):259-269.
[29]
毛智慧,邓磊,贺英,等.利用色调-亮度彩色分量的可见光植被指数[J]. 中国图像图形学报, 2017,22(11):1602-1610. Mao Z H, Deng L, He Y, et al. Vegetation index for visible-light true-color image using hue and lightness color channels[J]. Journal of Image and Graphics, 2017,22(11):1602-1610.
[30]
Hunt E R, Cavigelli M, Daughtry C S T, et al. Evaluation of digital photography from model aircraft for remote sensing of crop biomass and nitrogen status[J]. Precision Agriculture, 2005,6(4):359-378.
[31]
Abdelhalim Elazab, Jordi Bort, Zhou B W, et al. The combined use of vegetation indices and stable isotopes to predict durum wheat grain yield under contrasting water conditions[J]. Agricultural Water Management, 2015,158:196-208.
[32]
Woebbecke D M, Meyer G E, Bargen K V, et al. Plant species identification, size, and enumeration using machine vision techniques on near-binary images[J]. Proceedings of SPIE-The International Society for Optical Engineering, 1993,1836:208-219.
[33]
Gamon J A, Surfus J S. Assessing leaf pigment content and activity with a reflectometer[J]. New Phytologist,1999,143(1):105-117.
[34]
Sellaro R, María Crepy, Trupkin S A, et al. Cryptochrome as a Sensor of the blue/green ratio of natural radiation in arabidopsis[J]. Plant Physiology, 2010,154(1):401-409.
[35]
Meyer G E, Neto J C. Verification of color vegetation indices for automated crop imaging applications[J]. Computers and Electronics in Agriculture, 2008,63(2):282-293.
[36]
江杰,张泽宇,曹强,等.基于消费级无人机搭载数码相机监测小麦长势状况研究[J]. 南京农业大学学报, 2019,42(4):622-631. Jiang J, Zhang Z Y, Cao Q, et al. Use of a digital camera mounted on a consumer-grade unmanned aerial vehicle to monitor the growth status of wheat[J]. Journal of Nanjing Agricultural University, 2019,42(4):622-631.
[37]
Bareth G, Bolten A, Gnyp M L, et al. Comparison of uncalibrated rgbvi with spectrometer-based ndvi derived from uav sensing systems on field scale[J]. Isprs International Archives of the Photogrammetry Remote Sensing & Spatial Information Sciences, 2016,XLI-B8:837-843.
[38]
Bendig J, Yu K, Aasen H, et al. Combining UAV-based plant height from crop surface models, visible, and near infrared vegetation indices for biomass monitoring in barley[J]. International Journal of Applied Earth Observation & Geoinformation, 2015,39(7):79-87.
[39]
梁华为.直接从双峰直方图确定二值化阈值[J]. 模式识别与人工智能, 2002,15(2):253-256. Liang H W. Direct determination of threshold from bimodal histogram[J]. Pattern Recognition and Artificial Intelligence, 2002,15(2):253-256.
[40]
李了了,邓善熙,丁兴号.基于大津法的图像分块二值化算法[J]. 微计算机信息, 2005,21(8-3):76-77. Li L L, Deng S X, Ding X H, et al. Binarization algorithm based on image partition derived from Da-Jing method[J]. Microcomputer Information, 2005,21(8-3):76-77.