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Visualize a Radar image with ENVI [message #93152]

Tue, 03 May 2016 04:01

d.poreh
Messages: 406
Registered: October 2007

Senior Member

Folks,
Hi,
I have a radar image with complex numbers for each pixel. I want to visualize this image as amplitude like A=sqrt(im^2+re^2) in envi (or with other possible ways).
Can someone please help?
Thanks for any kind of help in advance:)
Cheers,
Dave

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Re: Visualize a Radar image with ENVI [message #93155 is a reply to message #93152]

Tue, 03 May 2016 05:32

Helder Marchetto
Messages: 520
Registered: November 2011

Senior Member

On Tuesday, May 3, 2016 at 12:01:07 PM UTC+1, dave poreh wrote:
> Folks,
> Hi,
> I have a radar image with complex numbers for each pixel. I want to visualize this image as amplitude like A=sqrt(im^2+re^2) in envi (or with other possible ways).
> Can someone please help?
> Thanks for any kind of help in advance:)
> Cheers,
> Dave

Could IDL's abs() function be of any help?
Have a look here:
http://www.harrisgeospatial.com/docs/ABS.html

Cheers,
Helder

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Re: Visualize a Radar image with ENVI [message #93157 is a reply to message #93152]

Tue, 03 May 2016 06:31

PMan
Messages: 61
Registered: January 2011

Member

On Tuesday, May 3, 2016 at 7:01:07 AM UTC-4, dave poreh wrote:
> Folks,
> Hi,
> I have a radar image with complex numbers for each pixel. I want to visualize this image as amplitude like A=sqrt(im^2+re^2) in envi (or with other possible ways).
> Can someone please help?
> Thanks for any kind of help in advance:)
> Cheers,
> Dave

Helder's approach will work if your data type is complex. You implement this in band math 'abs(b1)'. Also, I think you can set how complex data is presented in ENVI (amplitude, intensity, real, or imaginary) or at least there was a way in old 'Classic' viewer.

But in my experience, the real and imag parts split into two image bands. Then, in band math 'sqrt(b1^2 + b2^2)' will work

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Re: Visualize a Radar image with ENVI [message #93158 is a reply to message #93152]

Tue, 03 May 2016 06:38

PMan
Messages: 61
Registered: January 2011

Member

On Tuesday, May 3, 2016 at 7:01:07 AM UTC-4, dave poreh wrote:
> Folks,
> Hi,
> I have a radar image with complex numbers for each pixel. I want to visualize this image as amplitude like A=sqrt(im^2+re^2) in envi (or with other possible ways).
> Can someone please help?
> Thanks for any kind of help in advance:)
> Cheers,
> Dave

You can implement Helder's approach in 'Band Math.' Also, under the 'Raster management' toolbox, there is a function to convert complex data. https://www.harrisgeospatial.com/docs/managerasterdata.html# Convert

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Re: Visualize a Radar image with ENVI [message #93164 is a reply to message #93152]

Tue, 03 May 2016 23:44

d.poreh
Messages: 406
Registered: October 2007

Senior Member

On Tuesday, May 3, 2016 at 1:01:07 PM UTC+2, dave poreh wrote:
> Folks,
> Hi,
> I have a radar image with complex numbers for each pixel. I want to visualize this image as amplitude like A=sqrt(im^2+re^2) in envi (or with other possible ways).
> Can someone please help?
> Thanks for any kind of help in advance:)
> Cheers,
> Dave

Thanks I manage to work with BAND math :)
Cheers,
Dave

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