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Contributor
Posts: 24
Registered: ‎09-21-2017

Fusion of 2D Image and Elevation Image into a Single Image Containing the Merged Information

[ Edited ]
Staff
Posts: 576
Registered: ‎02-02-2016

Re: Fusion of 2D Image and Elevation Image into a Single Image Containing the Merged Information

Text from Julie's post:

 

I want to ask if you have an idea on how to fuse a 2D image and an elevation image into a single image with merged information from the two combined images? I am thinking of using layer stacking but I don't know if the information will also merge. 

Frequent Contributor
Posts: 153
Registered: ‎10-27-2015

Re: Fusion of 2D Image and Elevation Image into a Single Image Containing the Merged Information

I have done this and commented to Julie privately already too. In nutshell my trial has been simple layer stack and adding elevation layer as a one band. Then feeding this mixed data image to Objective and extracting buildings etc. My trials were not a total triumph to success but as an idea this is a way to feed image data and elevation data easily to single feature exctraction process. It is just question how smart the data can be processed in feature extraction and I did not find the optimal ways yet.

Regular Contributor
Posts: 212
Registered: ‎11-16-2015

Re: Fusion of 2D Image and Elevation Image into a Single Image Containing the Merged Information

[ Edited ]

I've done this as well, however using a relative height layer (DSM - DTM) and found it's worked a little better in Objective. It's a shame that the workflow isn't a little more customisable and that you can't use defined height layers in the raster processing steps. Roll on ERDAS IMAGINE 2018 with a lot of the Objective type operators in Spatial Modeler!

Frequent Contributor
Posts: 153
Registered: ‎10-27-2015

Re: Fusion of 2D Image and Elevation Image into a Single Image Containing the Merged Information

That I agree totally - height of objects above the ground - that is the name of the data I used. And I totally agree - waiting for 2018 and its new Objective based spatial model functions to see how much things get easier.
Technical Evangelist
Posts: 696
Registered: ‎10-01-2015

Re: Fusion of 2D Image and Elevation Image into a Single Image Containing the Merged Information

[ Edited ]

If you are going to layer-stack the terrain layer with your multispectral imagery as an input to IMAGINE Objective I would strongly recommend scaling the data to approximately similar ranges first. Otherwise the "aberrant" band can have an undue effect on the Objective process. 
So if your MS data is 11-bit (0 - 2047), scale the DEM to that range. Or vice versa.

Johnnie is correct - if you are trying to classify "off ground" items like trees, buildings, etc., having the DEM as Height Above Ground is much more likely to produce good results than Height Above Mean Sea Level. But if you are classifying vegetation types, which may depend on altitude, then ASL may give better results. 

 

...and don't forget that there's now an Ideas board if you want to make enhancement requests!

 

Cheers

 

Ian Anderson
Chief Product Owner, Desktop Remote Sensing
Hexagon Geospatial
Frequent Contributor
Posts: 153
Registered: ‎10-27-2015

Re: Fusion of 2D Image and Elevation Image into a Single Image Containing the Merged Information

I used it in way that some processes used RGB as a input and some used height layer. So I was not using kind of mixed but more like feeding all data including height into the system via single input file. Actually one idea was to use height above the ground (=DSM-DTM) as a single band for a file feeded to Principal Component analysis. The goal was to extract buildings and that should give good separation from flat ground. I think it is doable already now even without the new enhancements if you just find right operators and ways to processes the data. Most likely more doable in 2018 when Objective functions will get as a operators in Spatial Modeller.
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