[email protected] wrote: > > Thanks very much for your reply,Jordi. > > I have read the first paper, it need cloud and cloud shadow match, and > the processing was more complicated than OTB. > > As refer to OTB cloud detection method,I have another question:the OTB > cloud-detect method need specify a pixel which possibly is cloud, that > means it can not recognize cloud automatically.If someone adopt the > OTB cloud detection method to process large amount of images or run > real-time on-board the remote sensing satellite, Obviously, one can > not pick a cloud pixel for the OTB program.So my question is: > > Does there any techniques to determine the reference cloud spectral > angle automatically? Or could I just preset the reference cloud > spectral angle? > > I know that some methods such as SVM could train the cloud spectral > angle classifier which could act as a reference，Any other > suggestion?? >
Hi, I simple approach for which I have seen good results is indeed supervised classification. If you can generate a set of training samples (small polygons) for the cloud and for the non-cloud classes, you can use either SVM or Random Forests to implement your cloud screening procedure. In this case, you don't even have to code in C++ and you can use the OTB applications. Have a look here: https://www.orfeo-toolbox.org/CookBook/CookBookse14.html#x66-1010004.4 Good luck. Jordi > Thanks again! > > On Thursday, March 5, 2015 at 12:37:58 PM UTC, Jordi Inglada wrote: > > [email protected] wrote: > > > > Hello guys, > > > > Now I am a beginner to use the OTB and I have some problems when > using > > the Cloud Detection Example. > > > > As far as I know that there are several techniques to detect > cloud > > from the remote sensing imagery. In the OTB, it detects the > cloud > > based on spectral angle principle and assume that the image have > four > > spectral bands. In my mind the parameter setting should affect > the > > detection result, and the parameters must set according to > Sensor that > > the camera adopted.But not every cameras have four spectral > bands. > > > > So My questions are: > > > > Does there any papers about the OTB Cloud Detection method? > > > > Does it work well using only three spectral band? > > > > What is the basic principle to set the parameters? > > > > Anyone any suggestion is welcome! > > > > Thanks very much. > > > > -- > > Hi, > > You are right about the fact that there are many methods for the > detection of clouds. The spectral method proposed in OTB is a very > simple one (spectral angle and low-pass filtering before > thresholding), but has the advantage of not needing any particular > spectral band (SWIR or thermal, for instance). > > If you want more sophisticated approaches, you should try to > implement something inspired from Fmask[1] for single-date > acquisitions or from MACCS[2] for multi-temporal series. > > Jordi > > [1] Zhu, Zhe, and Curtis E. Woodcock. "Object-based cloud and > cloud shadow detection in Landsat imagery." Remote Sensing of > Environment 118 (2012): 83-94. > > [2] Hagolle, Olivier, et al. "A multi-temporal method for cloud > detection, applied to FORMOSAT-2, VENµS, LANDSAT and SENTINEL-2 > images." Remote Sensing of Environment 114.8 (2010): 1747-1755. -- -- Check the OTB FAQ at http://www.orfeo-toolbox.org/FAQ.html You received this message because you are subscribed to the Google Groups "otb-users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/otb-users?hl=en --- You received this message because you are subscribed to the Google Groups "otb-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
