Abstract
As the use of unmanned aerial vehicle (UAV) images rapidly increases so does the need for precise radiometric calibration. For UAV images, relative radiometric calibration is required in addition to the traditional vicarious radiometric calibration due to the small field of view. For relative radiometric calibration, some UAVs install irradiance sensors, but most do not. For UAVs without them, an intelligent scheme for relative radiometric calibration must be applied. In this study, a relative radiometric calibration method is proposed to improve the quality of a reflectance map without irradiance measurements. The proposed method, termed relative calibration by the optimal path (RCOP), uses tie points acquired during geometric calibration to define the optimal paths. A calibrated image from RCOP was compared to validation data calibrated with irradiance measurements. As a result, the RCOP method produces seamless mosaicked images with uniform brightness and reflectance patterns. Therefore, the proposed method can be used as a precise relative radiometric calibration method for UAV images.
Highlights
Remote sensing is a science that acquires information without contacting targets
This paper proposes a new method of relative radiometric calibration for unmanned aerial vehicle (UAV) images acquired without an irradiance sensor
The first is applying a series of relative calibrations in the order of image 4a.c1q. uViissiutiaolnI.nTtehrperseetactoinond oisf CapalpiblyraintigonthReecsoueltffis cients of vicarious calibration obtained from the reference imagTehteotharlleeotrheelartiivmeargaedsiowmitehtoriuctcraelilbartiavteioncamlibertahtoiodns.(RFCoOr Pcl,aRriCtyA, Sw, eancdalNl tohReCp)rwopeoreseadppmlieetdhotod UreAlaVtivime caagleibsrwatiitohnoubyt itrhreadoipatnimcea. lFpigauthre(sR1C3OsPh)o; wwse trheeferretfoletchtaenficrestmmaepthboydndaetuscrrailbceodlodrirceocmtlypoabsiotevseelaantidvepcsaeluibdroa-tiinofnrabreydaccqouloirsitcioomn pseoqsiuteesnc(ed-(fR)CfrAoSm) aRnCdOthPe, RseCcoAnSd, amnedthNodoRaCb,ovreesipsenctoivreellya.tivIne ocradliebrratotioconm(NpoarReCc)o. lors, each band was stretched based on the same range of reflectance
Summary
Remote sensing is a science that acquires information without contacting targets. Terrestrial, airborne, and spaceborne sensors have been used. Vicarious calibration converts DNs into spectral reflectance by installing ground reference panels with known reflectance on the ground and estimating conversion coefficients using the DNs of the targets and their reflectance [12,18]. For UAV images, we need relative radiometric calibration in addition to vicarious calibration, unless we install ground reference panels within the field of view of each image. For UAV cameras without an irradiance sensor, conversion coefficients have been estimated through regression analysis between the DNs of pixels on overlapping regions between two images [28] This method is prone to geometric distortions and pixels with radiometric anomalies [29] and they often result in visual discontinuity between adjacent scenes [30]. This paper proposes a new method of relative radiometric calibration for UAV images acquired without an irradiance sensor. The proposed method was verified by comparing its results with those from a calibrated image that uses an irradiance sensor
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
