intertronic Posted June 15, 2016 Report Share Posted June 15, 2016 Hi everyone, does anyone knows how to generate a digital surface model with some satellite imagery? it's possible to create a terrain from stereo imagery in ArcGIS? and with just f.ex. 3-5 images not stereo? References : https://en.wikipedia.org/wiki/Digital_elevation_model Quote Link to comment Share on other sites More sharing options...
intertronic Posted June 15, 2016 Author Report Share Posted June 15, 2016 the methods are (those definitions come from wikipedia): Image correlation : Other kinds of stereoscopic pairs can be employed using the digital image correlation method, where two optical images are acquired with different angles taken from the same pass of an airplane or an Earth Observation Satellite (such as the HRS instrument of SPOT5 or the VNIR band of ASTER). A special case, called stereophotogrammetry, involves estimating the three-dimensional coordinates of points on an object employing measurements made in two or more photographic images taken from different positions (see stereoscopy). Common points are identified on each image. A line of sight (or ray) can be constructed from the camera location to the point on the object. It is the intersection of these rays (triangulation) that determines the three-dimensional location of the point. More sophisticated algorithms can exploit other information about the scene that is known a priori, for example symmetries, in some cases allowing reconstructions of 3-D coordinates from only one camera position. Stereophotogrammetry is emerging as a robust non-contacting measurement technique to determine dynamic characteristics and mode shapes of non-rotating[5][6] and rotating structures.[7][8] Quote Link to comment Share on other sites More sharing options...
intertronic Posted June 15, 2016 Author Report Share Posted June 15, 2016 A guide from nasa http://www.lpi.usra.edu/lunar/tools/dems/Ohman_2013_ISIS-ASP-ArcMap_workflow.pdf Quote Link to comment Share on other sites More sharing options...
Lurker Posted June 16, 2016 Report Share Posted June 16, 2016 I dont think ArcGIS has the capability to extract DEM from stereo pair image with their function except there is an extension out there you can use ERDAS or other remote sensing software to do that basically, you need images that overlap each other, and the DEM can only extracted on the overlap section only, IMHO 1 Quote Link to comment Share on other sites More sharing options...
hiram Posted June 16, 2016 Report Share Posted June 16, 2016 I believe that these links can help in this topic ... luck http://gis.stackexchange.com/questions/41432/create-dem-from-stereo-pairs-using-arcgis-for-desktop-or-open-source-gis https://www.researchgate.net/post/How_can_i_create_a_Digital_Elevation_Model_from_satellite_Images https://www.harrisgeospatial.com/docs/introductiontodemextraction.html http://www.pcigeomatics.com/pdf/extracting_DEM_from_stereo_photos.pdf http://global.digitalglobe.com/sites/default/files/DEM_Extraction_from_WorldView_Imagery_in_PCI_Geomatics.pdf http://global.digitalglobe.com/sites/default/files/DEM_extraction_from_OR2A_Stereo_and_ERDAS_LPS.pdf http://www.isprs.org/proceedings/XXXVI/8-W27/krauss.pdf 1 Quote Link to comment Share on other sites More sharing options...
am2 Posted June 17, 2016 Report Share Posted June 17, 2016 Is this possible to create dem from Aster?How is its accuracy? You know I want a most update version of DEM to study rivers changed and things like that Quote Link to comment Share on other sites More sharing options...
intertronic Posted June 17, 2016 Author Report Share Posted June 17, 2016 it's a good idea to try with aster.. maybe with socet set you will create a DEM? i tried to create some DSM with multiple Very High Resolution satellite imagery (not stereo) with the NGATE and ASM Methods in Socet.. well the results are not perfect and I don't really get how it works behind the software, still it gives an idea how the region is.. 1 Quote Link to comment Share on other sites More sharing options...
am2 Posted June 17, 2016 Report Share Posted June 17, 2016 it's a good idea to try with aster.. maybe with socet set you will create a DEM? i tried to create some DSM with multiple Very High Resolution satellite imagery (not stereo) with the NGATE and ASM Methods in Socet.. well the results are not perfect and I don't really get how it works behind the software, still it gives an idea how the region is.. It is intresting..I want to use ArcGIS to achive it Quote Link to comment Share on other sites More sharing options...
Art409 Posted June 23, 2016 Report Share Posted June 23, 2016 Stereoscopic Principle involves 2 (or more) images of the same object captured from DIFFERENT positions. for presition is very importante the Base/Heigth ratio (Base: distance between images; heigth: Distance from image to object) In classic aerial photogrammetry a good B/H ratio round 0.6 The case of multiple "Very High Resolution satellite imagery (not stereo)" cited by intertronic, could obtain poor results due B/H ratio. Modern Photogrammetric techniques adresses ray-cloud photogrammetry, that (in very simplified words) involve several images of the same object (and several correlations), but this is not apllicable yet to satellite images. Aster images offers a good B/H ratio, (I belive is close to 0.6, but not sure). Process is relatively simple in some softwares. But I don't recall any modeule to do this in ArcGIS: Good option for software for this are: PCI Geomática, ASTER DTM (for ENVI); ENvi with DTM module, Erdas. You can also download ASTER DEM Products from the web. Final TIP: The use GCPs (Ground Control Points) IS VERY IMPORTANT. If you can't afford get them on field with a GPS (differential GPS), you can donwnload a Envi processed Image and a DEM, so use some ponts from that dataset. Regards Art 2 Quote Link to comment Share on other sites More sharing options...
intertronic Posted June 23, 2016 Author Report Share Posted June 23, 2016 Stereoscopic Principle involves 2 (or more) images of the same object captured from DIFFERENT positions. for presition is very importante the Base/Heigth ratio (Base: distance between images; heigth: Distance from image to object) In classic aerial photogrammetry a good B/H ratio round 0.6 The case of multiple "Very High Resolution satellite imagery (not stereo)" cited by intertronic, could obtain poor results due B/H ratio. Modern Photogrammetric techniques adresses ray-cloud photogrammetry, that (in very simplified words) involve several images of the same object (and several correlations), but this is not apllicable yet to satellite images. Aster images offers a good B/H ratio, (I belive is close to 0.6, but not sure). Process is relatively simple in some softwares. But I don't recall any modeule to do this in ArcGIS: Good option for software for this are: PCI Geomática, ASTER DTM (for ENVI); ENvi with DTM module, Erdas. You can also download ASTER DEM Products from the web. Final TIP: The use GCPs (Ground Control Points) IS VERY IMPORTANT. If you can't afford get them on field with a GPS (differential GPS), you can donwnload a Envi processed Image and a DEM, so use some ponts from that dataset. Regards Art Hi, there is this company called vricon how say they use satellite imagery (not stereo) in order to create a 3D model (DSM). They claim without any GCP the product they calculate has a good precision with 3m accuracy.. so how do they do it? http://www.vricon.com/technology/ http://www.vricon.com/wp-content/uploads/2015/12/Vricon_DSM_print.pdf Quote Link to comment Share on other sites More sharing options...
Art409 Posted June 25, 2016 Report Share Posted June 25, 2016 (edited) They use te same principle for 3D recosntruction: Stereovision. They simple calim, "the imagery does not need to be captured as traditional stereo pairs" but they use the stereoscopic pronciple. About GCPs there only 4 options: 1) They got a HUGE base of existants GCPs (or georreferenced images) 2) They got very precise oribital parameters (Similar to classic External Orientation) 3) they got any comercial secret unknow by scientists. 4) they lie (I don't think so) I'll like to add some reference numbers to explain my statement Here goes some numbrers about the need of accurate orbital parameters. A satellite height between 500 and 700km, implies velocities betwen 7.52 and 7.62 Km/s So... if you want satellite position better than 1 meter you need an accurate position 10.000 times by second (no GPS got that rate) So.. we must interpolate positions... Attitude: an error of 1 arc second means at 700 Km, 3.39m (2.42m at 500km), so... we need an attitude accuracy of 1/3" or better... Thats goes for an absolute geolocation of 3meters (despite heigths) Obviously you need attitude data at 10KHz rate (10.000 mesures, by second) Again. we must interpolate. The good news: At those heigths orbits are mostly smooths, and position and attitude changes are not violent, as in an aircraft. The Toutin’s Rigorous RPC Model (Toutin, 2002), was the better choice for that. A good paper on "COMPARISON OF DIFFERENT MATHEMATICAL MODELS ON THE ACCURACY OF THE ORTHORECTIFICATION OF ASTER IMAGERY" could be found here: http://www.isprs.org/proceedings/XXXVI/1-W41/makaleler/OK_Model_ASTER.pdf Art Edited June 26, 2016 by Art409 1 Quote Link to comment Share on other sites More sharing options...
intertronic Posted June 27, 2016 Author Report Share Posted June 27, 2016 thanks art409, I like your answer Quote Link to comment Share on other sites More sharing options...
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