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Euri Pinhollow
Euri Pinhollow
11:49 AM
@michael-clark: you say it like debayerisation is somehow obligated to not keep the values present in RAW file. Try dcraw -4 -T -M -r 1 1 1 1 -o 0 -q 1 -d and dcraw -4 -T -M -r 1 1 1 1 -o 0 -q 1 using same image (you might try using different -q <num>). I just did and was able to find same pixel values using ImageJ.
Surely any manipulation may be integrated into debayerisation. It's just it is not obligatory to do so (despite what you have written suggests).
Sharpening is the thing which may influence the present values yet it is in no way obligatory to merge it with debayerisation.
 
Jeff Teoh
Jeff Teoh
Hi
what kind of compact camera would you recommend for travelling?
 
Euri Pinhollow
Euri Pinhollow
Additionally, I tried -q 3 and got same result - present values were preserved.
@JeffTeoh it really depends on what you want. IIRC I would prefer taking a bigger camera like Panasonic FZ1000 or Sony RX10.
 
Jeff Teoh
Jeff Teoh
I tried action cams before did not work out for me haha
I was thinking of Canon PowerShot SX610 HS 20.2MP 18x Optical Zoom Camera - Black
 
Euri Pinhollow
Euri Pinhollow
12:09 PM
You may but you should not take final decision without holding a camera personally. The selection is like this:
- select cameras with suitable tech characteristics
- filter cameras with bad images
- hold them in shop or whereever else
@JeffTeoh there is not too much to say about cameras other than you can and should learn youself.
 
Jeff Teoh
Jeff Teoh
I agree with that.
What camera do you use?
 
Euri Pinhollow
Euri Pinhollow
@JeffTeoh I used Panasonic FZ50 and Fujifilm S100FS before I got DSLR.
I was especially happy with S100FS because of faster RAW file recording.
I chose both primarily because of mechanical zoom ring.
It means that zooming does not involve electronics.
 
Jeff Teoh
Jeff Teoh
Wow, you sure do know a lot about photography.
 
Euri Pinhollow
Euri Pinhollow
Not exceptionally much. You may generally find even more skilled or knowledgeable people in Photo.SE.
 
Jeff Teoh
Jeff Teoh
Alright.
 
Euri Pinhollow
Euri Pinhollow
12:23 PM
The most important part of choosing a camera is taking a personal look at it to understand how it suites you while performing basic actions.
Reading an instruction manual (downloadable for most cameras) is good too.
 
Jeff Teoh
Jeff Teoh
I see, I guess each type of camera has their own benefits.
Well, I gtg.
Good Night!
 
 
4 hours later…
Michael Clark
Michael Clark
4:12 PM
@EuriPinhollow Please go back and read my comment again. Your response indicates I did not say what you think I said. But even if I had said that, it is certainly true that no major commercial raw conversion application does demosaicing the way you suggest because it won't yield accurate color. It is certainly possible to produce an image from a raw file without doing any demosaicing at all, but it wouldn't be a very realistic representation of the scene now would it?
 
Euri Pinhollow
Euri Pinhollow
4:35 PM
"Please go back and read my comment again." - I did and it did not become clearer to me what you wanted to say (assuming that I have misunderstood you).

"But even if I had said that, it is certainly true that no major commercial raw conversion application does demosaicing the way you suggest" - do you have a source code of all of the commercial software to confirm it? Alternatively, does any commercial software does explicitly state what does used debayerisation algorithm represent itself?

"but it wouldn't be a very realistic representation of the scene now would it?" - yes it would besid…
 
Euri Pinhollow
Euri Pinhollow
5:06 PM
@MichaelClark I have seen another comment from you. Are you sure that you are not mixing debayerisation with colour conversion which is universally required, not for Bayer sensors only?
 
Michael Clark
Michael Clark
5:30 PM
@EuriPinhollow So the world looks like a checkerboard with half the squares green and the other half divided between red and blue? And human vision responds to the same intensity of red, green, and blue light respectively with the same perceived brightness? Really?
 
Euri Pinhollow
Euri Pinhollow
3->4 is debayerisation and 2 and 3 are different illustrations for same Bayer image. Besides that, what exactly do you want to communicate?
:29984314
 
Michael Clark
Michael Clark
5:46 PM
3 is a colorized version of 2 where each green filtered pixel is converted from gray to the same value for green (with no blue or red component), each red filtered pixel is converted from gray to the same value for red (with no green or blue component), and so on.
Your comment above seems to indicate you think 3 is a realistic representation of the scene.
 
Euri Pinhollow
Euri Pinhollow
@MichaelClark your comments seem to indicate that you think that 2->3 is debayerisation and thus 3 is the result of debayerisation (which is synonym for demosaicing or vice versa). This is false.
@MichaelClark 2 and 3 represent the difference between knowing the CFA pattern and not knowing it. 2->3 is not a distinct step in any algorithm which I know besides reading CFA pattern from metadata or database.
 
Michael Clark
Michael Clark
@EuriPinhollow What makes you say that? You are the one that is claiming using a 1:1 color value for the monochromatic values in 2 will create a realistic rendering of the scene, not me.
@EuriPinhollow Which is exactly what I have been saying and you have been disputing!
 
Euri Pinhollow
Euri Pinhollow
6:27 PM
I claim that at least one piece of software (the most popular in RAW managing programs) guesses two stimuli (having only one known) and verified it by studying both grayscale and debayered output from `dcraw` which showed that I do find the numerical value of each Bayer pixel inside of at least one channel of produced tristimulus image. You claim that software guesses all thre colours and did not yet provide a basis for this claim.

"using a 1:1 color value for the monochromatic values in 2" - I cannot understand what it means let alone remember the point at which I said that.
 

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