{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:11:00Z","timestamp":1760242260491,"version":"build-2065373602"},"reference-count":59,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2017,2,16]],"date-time":"2017-02-16T00:00:00Z","timestamp":1487203200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"publisher","award":["No.2572015AB15"],"award-info":[{"award-number":["No.2572015AB15"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100010015","name":"Special Fund for Forest Scientific Research in the Public Welfare","doi-asserted-by":"publisher","award":["No. 201504319"],"award-info":[{"award-number":["No. 201504319"]}],"id":[{"id":"10.13039\/501100010015","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The range between a sensor and the target, the incidence angle, and the target reflectance, are known factors that can influence the intensity values of LiDAR data and consequently, its use in many applications. However, very few studies have provided a quantitative analysis of the effects of normalisation of these three factors on forest leaf area index (LAI) estimations. In this paper, using two coniferous tree species (i.e., Scotch pine and Larch pine) as a case study, the effects of intensity normalisation on coniferous forest LAI estimations have, for the first time, been systematically examined and quantified. It was found that the intensity normalisation had a generally positive effect on the improvement of coniferous forest LAI estimations. However, the improvements were very minor. Specifically, the range normalisation did not improve the accuracy of the LAI estimation for either of the two coniferous tree species. The incidence angle and reflectance normalisation improved the accuracy of the LAI estimation for Scotch pine forests; however, they had no effect on the improvement of the LAI estimation for Larch pine forests. This experimental study suggests that range normalisation is not required for forest LAI estimations in areas with small elevation differences (i.e., less than 114 m). The incidence angle and target reflectance normalisation can marginally improve the accuracy of coniferous forest LAI estimations. However, the extent of this improvement varies among species, depending on the choice of incidence angle and reflectance coefficient. Overall, the effects of normalisation of airborne LiDAR intensity on coniferous forest LAI estimations are closely related to topographic conditions (i.e., elevation and slope), the tree species composition, and its associated structural attributes. Therefore, further research should explore the effects of LiDAR intensity normalisation on forest LAI estimations in regions with large elevation differences and diverse forest structures.<\/jats:p>","DOI":"10.3390\/rs9020163","type":"journal-article","created":{"date-parts":[[2017,2,16]],"date-time":"2017-02-16T12:55:34Z","timestamp":1487249734000},"page":"163","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":25,"title":["Quantifying the Effects of Normalisation of Airborne LiDAR Intensity on Coniferous Forest Leaf Area Index Estimations"],"prefix":"10.3390","volume":"9","author":[{"given":"Haotian","family":"You","sequence":"first","affiliation":[{"name":"Centre for Forest Operations and Environment, College of Engineering and Technology, Northeast Forestry University, Harbin 150040, China"},{"name":"Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1138-8464","authenticated-orcid":false,"given":"Tiejun","family":"Wang","sequence":"additional","affiliation":[{"name":"Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7446-8429","authenticated-orcid":false,"given":"Andrew","family":"Skidmore","sequence":"additional","affiliation":[{"name":"Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands"}]},{"given":"Yanqiu","family":"Xing","sequence":"additional","affiliation":[{"name":"Centre for Forest Operations and Environment, College of Engineering and Technology, Northeast Forestry University, Harbin 150040, China"}]}],"member":"1968","published-online":{"date-parts":[[2017,2,16]]},"reference":[{"key":"ref_1","first-page":"213","article-title":"The effects of laser reflection angle on radiometric correction of airborne LiDAR intensity data","volume":"3812","author":"Shaker","year":"2011","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_2","first-page":"44","article-title":"Lidar remote sensing for forestry","volume":"98","author":"Dubayah","year":"2000","journal-title":"J. For."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Maltamo, M., N\u00e6sset, E., and Vauhkonen, J. (2014). Forestry Applications of Airborne Laser Scanning: Concepts and Case Studies, Springer.","DOI":"10.1007\/978-94-017-8663-8"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1016\/j.rse.2015.08.019","article-title":"Lidar waveform features for tree species classification and their sensitivity to tree-and acquisition related parameters","volume":"173","author":"Hovi","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1093\/oxfordjournals.aob.a083148","article-title":"Comparative physiological studies on the growth of field crops: I. Variation in net assimilation rate and leaf area between species and varieties, and within and between years","volume":"11","author":"Watson","year":"1947","journal-title":"Ann. Bot."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1111\/j.1365-3040.1992.tb00992.x","article-title":"Defining leaf area index for non-flat leaves","volume":"15","author":"Chen","year":"1992","journal-title":"Plant Cell Environ."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1016\/j.foreco.2015.09.030","article-title":"An improved theoretical model of canopy gap probability for leaf area index estimation in woody ecosystems","volume":"358","author":"Woodgate","year":"2015","journal-title":"For. Ecol. Manag."},{"key":"ref_8","unstructured":"Finney, M.A. (2004). FARSITE: Fire Area Simulator: Model Development and Evaluation."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.rse.2006.04.019","article-title":"Estimation of LAI and fractional cover from small footprint airborne laser scanning data based on gap fraction","volume":"104","author":"Morsdorf","year":"2006","journal-title":"Remote Sens. Environ."},{"key":"ref_10","unstructured":"Kwak, D.A., Lee, W.K., and Cho, H.K. (2007, January 12\u201314). Estimation of LAI using LiDAR remote sensing in forest. Proceedings of the ISPRS Workshop on Laser Scanning 2007 and SilviLaser 2007, Espoo, Finland."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1016\/0034-4257(88)90028-4","article-title":"Estimating forest biomass and volume using airborne laser data","volume":"24","author":"Nelson","year":"1988","journal-title":"Remote Sens. Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1641\/0006-3568(2002)052[0019:LRSFES]2.0.CO;2","article-title":"LiDAR remote sensing for ecosystem studies","volume":"52","author":"Lefsky","year":"2002","journal-title":"Bioscience"},{"key":"ref_13","unstructured":"Solberg, S. (2008, January 17\u201319). Comparing discrete echoes counts and intensity sums from ALS for estimating forest LAI and gap fraction. Proceedings of the SilviLaser 2008: 8th International Conference on LiDAR Applications in Forest Assessment and Inventory, Edinburgh, UK."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/j.foreco.2011.12.048","article-title":"Estimating leaf area index in intensively managed pine plantations using airborne laser scanner data","volume":"270","author":"Peduzzi","year":"2012","journal-title":"For. Ecol. Manag."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"3097","DOI":"10.1080\/01431160500217277","article-title":"Radiometric correction in laser scanning","volume":"27","author":"Coren","year":"2006","journal-title":"Int. J. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"740","DOI":"10.1109\/JSTARS.2014.2354014","article-title":"Characterizing radiometric attributes of point cloud using a normalized reflective factor derived from small footprint LiDAR waveform","volume":"8","author":"Qin","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"942","DOI":"10.1109\/TGRS.2014.2330852","article-title":"Intensity correction of terrestrial laser scanning data by estimating laser transmission function","volume":"53","author":"Fang","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.isprsjprs.2015.12.004","article-title":"Correction of terrestrial LiDAR intensity channel using Oren\u2013Nayar reflectance model: An application to lithological differentiation","volume":"113","author":"Carrea","year":"2016","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"304","DOI":"10.1109\/JSTARS.2015.2497310","article-title":"Intensity data correction for the distance effect in terrestrial laser scanners","volume":"9","author":"Tan","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1109\/LGRS.2005.850534","article-title":"Study of surface brightness from backscattered laser intensity: Calibration of laser data","volume":"2","author":"Kaasalainen","year":"2005","journal-title":"IEEE Geosci. Remote Sens."},{"key":"ref_21","first-page":"201","article-title":"Radiometric calibration of ALS intensity","volume":"36","author":"Kaasalainen","year":"2007","journal-title":"Int. Arch. Photogramm. Remote Sens."},{"key":"ref_22","first-page":"405","article-title":"Intensity normalization by incidence angle and range of full-waveform LiDAR data","volume":"37","author":"Gross","year":"2008","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1016\/j.isprsjprs.2010.06.007","article-title":"Radiometric calibration of small-footprint full-waveform airborne laser scanner measurements: Basic physical concepts","volume":"65","author":"Wagner","year":"2010","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.compag.2012.02.020","article-title":"Combining LiDAR intensity with aerial camera data to discriminate agricultural land uses","volume":"84","author":"Porras","year":"2012","journal-title":"Comput. Electron. Agric."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/j.isprsjprs.2011.10.005","article-title":"Improving classification accuracy of airborne LiDAR intensity data by geometric calibration and radiometric correction","volume":"67","author":"Yan","year":"2012","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1016\/j.isprsjprs.2010.04.003","article-title":"Range and AGC normalization in airborne discrete-return LiDAR intensity data for forest canopies","volume":"65","author":"Korpela","year":"2010","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"415","DOI":"10.1016\/j.isprsjprs.2007.05.008","article-title":"Correction of laser scanning intensity data: Data and model-driven approaches","volume":"62","author":"Pfeifer","year":"2007","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1433","DOI":"10.1080\/01431160701736398","article-title":"3D vegetation mapping using small-footprint full-waveform airborne laser scanners","volume":"29","author":"Wagner","year":"2008","journal-title":"Int. J. Remote Sens."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1016\/j.rse.2008.09.012","article-title":"Testing LiDAR models of fractional cover across multiple forest ecozones","volume":"113","author":"Hopkinson","year":"2009","journal-title":"Remote Sens. Environ."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2569","DOI":"10.1080\/01431161.2015.1041177","article-title":"Use of airborne LiDAR for estimating canopy gap fraction and leaf area index of tropical montane forests","volume":"36","author":"Heiskanen","year":"2015","journal-title":"Int. J. Remote Sens."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1227","DOI":"10.1080\/01431160903380672","article-title":"Mapping gap fraction, LAI and defoliation using various ALS penetration variables","volume":"31","author":"Solberg","year":"2010","journal-title":"Int. J. Remote Sens."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1002\/cjg2.20024","article-title":"Forest leaf area index (LAI) estimation using airborne discrete-return LiDAR data","volume":"56","author":"Luo","year":"2013","journal-title":"Chin. J. Geophys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2317","DOI":"10.1016\/j.rse.2009.06.010","article-title":"Mapping LAI in a Norway spruce forest using airborne laser scanning","volume":"113","author":"Solberg","year":"2009","journal-title":"Remote Sens. Environ."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1080\/01431161.2015.1117683","article-title":"Estimating leaf area index at multiple heights within the understorey component of Loblolly pine forests from airborne discrete-return LiDAR","volume":"37","author":"Sumnall","year":"2016","journal-title":"Int. J. Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1016\/S0168-1923(99)00018-0","article-title":"Leaf area index estimates obtained for clumped canopies using hemispherical photography","volume":"94","author":"Jackson","year":"1999","journal-title":"Agric. For. Meteorol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1628","DOI":"10.1016\/j.rse.2009.03.006","article-title":"Lidar-based mapping of leaf area index and its use for validating GLOBCARBON satellite LAI product in a temperate forest of the southern USA","volume":"113","author":"Zhao","year":"2009","journal-title":"Remote Sens. Environ."},{"key":"ref_37","unstructured":"Schaefer, M., Farmer, E., Soto-Berelov, M., Woodgate, W., and Jones, S. (2015). AusCover Good Practice Guidelines: A Technical Handbook Supporting Calibration and Validation Activities of Remotely Sensed Data Product, TERN AusCover."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/j.rse.2015.02.025","article-title":"Mapping urban forest leaf area index with airborne LiDAR using penetration metrics and allometry","volume":"162","author":"Alonzo","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"332","DOI":"10.1016\/j.rse.2004.05.015","article-title":"Radiative transfer modeling within a heterogeneous canopy for estimation of forest fire fuel properties","volume":"92","author":"Schaepman","year":"2004","journal-title":"Remote Sens. Environ."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"872","DOI":"10.1109\/TGRS.2003.810682","article-title":"A progressive morphological filter for removing nonground measurements from airborne LiDAR data","volume":"41","author":"Zhang","year":"2003","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_41","first-page":"111","article-title":"DEM generation from laser scanner data using adaptive TIN models","volume":"33","author":"Axelsson","year":"2000","journal-title":"Int. Arch. Photogramm. Remote Sens."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"308","DOI":"10.1016\/j.rse.2016.02.012","article-title":"Assessing the transferability of statistical predictive models for leaf area index between two airborne discrete return LiDAR sensors designs within multiple intensely managed loblolly pine forest locations in the south-eastern USA","volume":"176","author":"Sumnall","year":"2016","journal-title":"Remote Sens. Environ."},{"key":"ref_43","unstructured":"Jelalian, A.V. (October, January 29). Laser radar systems. Proceedings of the Electronics and Aerospace Systems Conference, Arlington, VA, USA."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1016\/j.isprsjprs.2006.09.001","article-title":"Range determination with waveform recording laser systems using a wiener filter","volume":"61","author":"Jutzi","year":"2006","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1016\/j.isprsjprs.2011.02.002","article-title":"B-spline deconvolution for differential target cross-section determination in full-waveform laser scanning data","volume":"66","author":"Roncat","year":"2011","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"7658","DOI":"10.1109\/TGRS.2014.2316195","article-title":"Radiometric correction and normalization of airborne LiDAR intensity data for improving land-cover classification","volume":"52","author":"Yan","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"816","DOI":"10.1016\/j.rse.2009.11.021","article-title":"Estimating biomass carbon stocks for a Mediterranean forest in central Spain using LiDAR height and intensity data","volume":"114","author":"Chuvieco","year":"2010","journal-title":"Remote Sens. Environ."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"251","DOI":"10.14358\/PERS.77.3.251","article-title":"Dynamic range-based intensity normalization for airborne, discrete return LiDAR data of forest canopies","volume":"77","author":"Gatziolis","year":"2011","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_49","unstructured":"Shaker, A., Yan, W.Y., and El-Ashmawy, N. (2011, January 29\u201331). The effects of laser reflection angle on radiometric correction of airborne LiDAR intensity data. Proceedings of the ISPRS Workshop Laser Scanning, Calgary, AB, Canada."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Rees, G., and Rees, W.G. (2013). Physical Principles of Remote Sensing, Cambridge University Press.","DOI":"10.1017\/CBO9781139017411"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2207","DOI":"10.3390\/rs3102207","article-title":"Analysis of incidence angle and distance effects on terrestrial laser scanner intensity: Search for correction methods","volume":"3","author":"Kaasalainen","year":"2011","journal-title":"Remote Sens."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/S0034-4257(98)00071-6","article-title":"Surface LiDAR remote sensing of basal area and biomass in deciduous forests of eastern Maryland, USA","volume":"67","author":"Lefsky","year":"1999","journal-title":"Remote Sens. Environ."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"3947","DOI":"10.1016\/j.rse.2008.07.001","article-title":"Discrete return LiDAR -based prediction of leaf area index in two conifer forests","volume":"112","author":"Jensen","year":"2008","journal-title":"Remote Sens. Environ."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"1065","DOI":"10.1016\/j.rse.2010.12.011","article-title":"Airborne discrete-return LiDAR data in the estimation of vertical canopy cover, angular canopy closure and leaf area index","volume":"115","author":"Korhonen","year":"2011","journal-title":"Remote Sens. Environ."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"390","DOI":"10.1016\/j.rse.2006.02.022","article-title":"Retrieving forest structure variables based on image texture analysis and IKONOS-2 imagery","volume":"102","author":"Kayitakire","year":"2006","journal-title":"Remote Sens. Environ."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"312","DOI":"10.5589\/m07-029","article-title":"The influence of flying altitude, beam divergence, and pulse repetition frequency on laser pulse return intensity and canopy frequency distribution","volume":"33","author":"Hopkinson","year":"2007","journal-title":"Can. J. Remote Sens."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1007\/s11355-013-0222-y","article-title":"Estimation of leaf area index and gap fraction in two broad-leaved forests by using small-footprint airborne LiDAR","volume":"12","author":"Sasaki","year":"2016","journal-title":"Landsc. Ecol. Eng."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"986","DOI":"10.1364\/AO.47.000986","article-title":"Effect of incidence angle on laser scanner intensity and surface data","volume":"47","author":"Kukko","year":"2008","journal-title":"Appl. Opt."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1016\/0034-4257(86)90046-5","article-title":"The spectral reflectance of stands of Norway spruce and Scotch pine, measured from a helicopter","volume":"20","author":"Kleman","year":"1986","journal-title":"Remote Sens. Environ."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/2\/163\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:28:27Z","timestamp":1760207307000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/9\/2\/163"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,2,16]]},"references-count":59,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2017,2]]}},"alternative-id":["rs9020163"],"URL":"https:\/\/doi.org\/10.3390\/rs9020163","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2017,2,16]]}}}