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Contributor
Posts: 45
Registered: ‎05-11-2017
Accepted Solution

Black fill around image after mosaic

Dear Community members,

 

I have problem with  black fill around  images.

 

Images delivered by Digital Globe comes divided to tiles.

 

I have used Mosaic Pro to merge tiles in to one IMG files and I forgot to set up parameter "Ignore Input Values" to 0 on Output Options tab under Output file name dialog.

 

Resulting IMG has black fill around images. All pixels in black fill have value 1

 

Is there any way to change pixel value of all pixels where all 4 bands have value 1?

 

Best regards,

Micko

Regular Contributor
Posts: 219
Registered: ‎11-16-2015

Re: Black fill around image after mosaic

Hiya. You shouldn't need to mosaic these tiles; DG data should come with a .TIL file that you can use natively within IMAGINE. If you use File > Open Raster Layer you will need to put an * in the file selector box to expose the .TIL file. Select it, it will create pyramid layers and you can use it as if it's a single file. Essentially you can treat it as a virtual mosaic.

Contributor
Posts: 45
Registered: ‎05-11-2017

Re: Black fill around image after mosaic

Thanks Johnnie.

 

I know about ,til but i have already created img files and created block file with that IMGs. Now I have to perform orthorectification of IMGs, but I whant to remove black fill if it is possible.

 

Micko

Technical Evangelist
Posts: 761
Registered: ‎10-01-2015

Re: Black fill around image after mosaic

[ Edited ]

A quick Spatial Model which changes pixels where all bands equal 1 to 0 instead, should fix the problem. 

 

In fact you may also want to make sure that 0 is then set to NoData (using the Set to NoData operator). 

Ian Anderson
Chief Product Owner, Desktop Remote Sensing
Hexagon Geospatial
Contributor
Posts: 45
Registered: ‎05-11-2017

Re: Black fill around image after mosaic

Hi Ian,

Thanks a lot.

 

I am not familiar with Spatial Modeler. How complicated is to make this model?

 

Micko

Technical Evangelist
Posts: 761
Registered: ‎10-01-2015

Re: Black fill around image after mosaic

Hi Micko,

 

The attached Model should do what you need. It checks for pixels where all four bands are DN value 1, sets those to a value that shouldn't be in use in a DigitalGlobe image, converts that value to NoData and then (assuming you are outputting an IMG file) uses 0 as the value-based NoData in the output file.

 

Reset_Background.PNG

 

Cheers

 

Ian Anderson
Chief Product Owner, Desktop Remote Sensing
Hexagon Geospatial
Regular Contributor
Posts: 219
Registered: ‎11-16-2015

Re: Black fill around image after mosaic

I had a quick look at this, got that far and then got sidetracked. Is there any way to elegently put the looking for 1 values in an iterator operator?

Technical Evangelist
Posts: 761
Registered: ‎10-01-2015

Re: Black fill around image after mosaic

Not really. An iterator would evaluate the bands independanlty, whereas you need to evaluate them in combination / simultaneously to identify all the 1,1,1,1s. You could probably do it, but it wouldn't be elegant. Possibly better to use Stack Total = Number of Bands and Stack Diversity = 1.

 

Cheers

 

Ian Anderson
Chief Product Owner, Desktop Remote Sensing
Hexagon Geospatial
Regular Contributor
Posts: 219
Registered: ‎11-16-2015

Re: Black fill around image after mosaic

Cool, that would do it. Ta, J

Contributor
Posts: 45
Registered: ‎05-11-2017

Re: Black fill around image after mosaic

Dear Ian,

 

thanks a lot.

 

This works fine.

 

I have just one more question. Is there any way to edit input file instead to create output file?

 

Best regards,

Mladen

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