[Radiance-general] Pcomb to mask an area of one image on to another

[Christian Humann]

Hi Greg and Stephen,

My discriminator was giving me odd results.  Stephen’s example helped me in writing the correct expression to pcomb.  

pcomb -e 'thresh=.2' -e 'ro=if(gi(1)-thresh*bi(2),ri(2),ri(1));go=if(gi(1)-thresh*bi(2),gi(2),gi(1));bo=if(gi(1)-thresh*bi(2),bi(2),bi(1))' image_1.hdr image_2.hdr  > modified.hdr

Thanks for the fast responses.
Chris

On Feb 29, 2016, at 5:03 PM, Greg Ward <gregoryjward at gmail.com> wrote:

> Hi Chris,
> 
> Is it that your discriminator isn't segmenting the image as you would like?
> 
> It would help if  you gave the full command you are using.  Your expression snippet isn't a legal option to pcomb.
> 
> Cheers,
> -Greg
> 
>> From: Christian Humann <chris at christianhumann.com>
>> Subject: [Radiance-general] Pcomb to mask an area of one image on to another
>> Date: February 29, 2016 4:45:58 PM PST
>> 
>> Greetings,
>> 
>> (apologies for the duplicate post which I errantly posted in haste the first time by using reply to another subject)
>> 
>> I’d like to write an expression within pcomb to mask the area of green trees in one  HDR fisheye scene and apply those selected pixels in the same location on a second image (both images are the same resolution).  Here’s an example of what I’m trying to do:
>> https://gyazo.com/932e7a14d64c35bff1802bcd11acc053
>> 
>> I’m getting close, but just can’t quite get there with the correct syntax using a threshold value for green [ex: -e 'gi(1)-thres*gi(2)’]
>> 
>> Thanks,
>> Chris
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