So I have a 16bit grayscale image
and I need to extract the first 8bits and put that in the the R channel
and then put the next 8bits into the G channel
and then export an 8bit image of RGB where B is black.
That will allow me to keep detail but keep things as an 8bit image.
Need some pointers on this for Hcomposite? i don't want to do this in Photoshop.
thanks
-k
16bit image separation
5003 4 2- thekenny
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- grayOlorin
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would the idea be that you want 0 to 0.5 stored in red and 0.5 to 1.0 stored in green? if so, try this in COPs
- use a file COP to bring in your 16 bit image
- use a color COP to create a 8 bit image of the same res as the 16 bit image
- drop a VOP COP filter and feed in the first input your color COP, and in the second input your 16 bit image
- dive inside the VOP COP, and use a COP input VOP to import the second input image plane (the 16 bit one)
- compare the incoming pixel with a compare VOP and see if it is less than 0.5
- feed the result into a two way switch COP condition input
- feed the incoming pixel to a get vector component VOP to get the first element (since it is grayscale)
- feed the output of that into two different float to vectors: one that inputs into the red, the other one into the green
- out of each one of those, use a fit VOP to stretch the red from 0-0.5 to 0-1, and the green from 0.5-1 to 0-1
- feed the output vectors of those into the two way switch so tha tthe appropriate shuffle happens depending on the pixel value
- feed the output of the two way switch to he output of the VOP COP
-assuming I did not forget anything and understood your question, you should be done
- switch the image in the file COP to convert as many images as you want
- use a file COP to bring in your 16 bit image
- use a color COP to create a 8 bit image of the same res as the 16 bit image
- drop a VOP COP filter and feed in the first input your color COP, and in the second input your 16 bit image
- dive inside the VOP COP, and use a COP input VOP to import the second input image plane (the 16 bit one)
- compare the incoming pixel with a compare VOP and see if it is less than 0.5
- feed the result into a two way switch COP condition input
- feed the incoming pixel to a get vector component VOP to get the first element (since it is grayscale)
- feed the output of that into two different float to vectors: one that inputs into the red, the other one into the green
- out of each one of those, use a fit VOP to stretch the red from 0-0.5 to 0-1, and the green from 0.5-1 to 0-1
- feed the output vectors of those into the two way switch so tha tthe appropriate shuffle happens depending on the pixel value
- feed the output of the two way switch to he output of the VOP COP
-assuming I did not forget anything and understood your question, you should be done
- switch the image in the file COP to convert as many images as you want
-G
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- tamte
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- olliRJL
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MartybNzReally? …that sounds like quite an interesting computing architecture
Then you should use all available channels. ie. r,g,b,a - you could then get 256*4=1024. A 10bit integer file.
An rgba image with 8bits per channel can (ofcourse) store 4*8=32bits of data so packing 16bits into two of those channels is no problem.
Try this in an inline vex code vopcop node to pack and unpack to and from 0-1 range float values.
// pack
int int_R = int($R * 0xffff);
$R_out = float(int_R & 0xff) / 256.0; // low 8 bits
$G_out = float(shr(int_R,8)) / 256.0; // hi 8 bits
// unpack
int int_R = int($R * 256);
int int_G = int($G * 256);
$R_out = float( shl(int_G,8) | int_R ) / float(0xffff);
…and watch out for gamma/colorspace transformations when writing the data out…
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