LibRaw is internally 16-bit unsigned int, so float conversion looks useless.
For 16-bit output just use explicit type conversion to (ushort*) for libraw_processed_image_t->data.
From what you said, it seems like the "white balance" is necessary before normal demosaic. If a user want to supply her/his own white balance factors, it can still be done through "user_mul[i]", correct?
Also, when I use "output_color = 0" and "half_size = 1" together (regardless other parameter), the image seems to look strange. Can you take a look at it?
I would like to use the RAW data without calling "dcraw_mem_image()"; however, there is still a need for demosaic. Currently, I have to use "dcraw_mem_image()" with the parameters listed before to get it as close as possible.
If there is a function that I can call to get the image data that only goes through demosaic step (with no other adjustment), that would be great!
"Unaltered image" is something close to what I am interested. Given the parameters that I enlisted, do they look reasonable to get the "Unaltered image"?
Also, only if you have time, would you mind replicating my test by adding "half_size = 1" (see below) and see if the converted image looks correct?
I understand there are several steps if dcraw_process () is called. Since I am interested in getting the image data that is very close to the "demosaic RAW", I manually set some parameter to "avoid" unnecessary processing on the RGB code values. For example, I did the following:
I did not understand exactly what you want
Standard raw processing sequence is (for decoded/linearized data) in dcraw_process is
- black subtraction
- white balance
- demosaic
- data scaling to use full range
- conversion to output color space
Than, on output
- brightness correction
- gamma curve
What stages do you need and what is not?
BTW, besides demosaic, all other steps are trivial and very easy to implement.
I meant the "raw image data" that only has demosaic process. In this case, I may still need "dcraw_process", right? if it is, then when I use "output_color = 0" and "half_size = 1", the output seems like missing a channel.
To get fully unprocessed raw data you may
1) Access imgdata.rawimage.raw_data array which stores raw values read from sensor as is
2) set params.half_size=1 and call raw2image() after unpack (instead of dcraw_process).
raw2image will arrange raw_data to imgdata.image[][4] array
Nice and thanks! I think the only issue for having this be a general solution (and not just having me rework the source a touch - fine for me, but...) is that scale_colors is protected rather than public.
unpack() is affected by camera_wb only in some (very rare) cases (I can not remember the details, it affects very small set of cameras, may be old Kodaks and/or foveon /old ones, before Sigma Merill).
For modern cameras unpack is not affected by color setting (but default for 'use_camera_matrix' for some cameras depends on wb settings)
subtract_black and scale_colors works with image[][4] array, so you need to call raw2image() before subtract_black().
Also, there is single call for raw2image and subtract_black:
int LibRaw::raw2image_ex(int do_subtract_black);
So:
open_file()
unpack();
raw2image_ex(1);
scale_colors();
will put black-subtracted and white-balanced image in image[][4]
Thank you for all the details! I've been using:
RawProcessor.raw2image()
CFA data then from RawProcessor.imgdata.image[r*RAW_S.iwidth+c][RawProcessor.FC(r,c)]
in my code since ... well, a long time ago... to extract the unprocessed data for Bayer-matrix data. (The idea being, I do my own hot pixel / bad pixel mapping -- this is astrophotography work). When non-Bayer, I run:
RawProcessor.dcraw_process();
red data then from RawProcessor.imgdata.image[r*RAW_S.iwidth+c][0]
green from[1], blue from [2]
I poked around in the debugger and docs last night but still couldn't see the effect of use_camera_wb. The docs (http://www.libraw.org/docs/API-notes.html#imgdata_params) say that unpack() is affected by this but no matter what the setting, the output of raw2image() seems the same.
For Bayer matrices, is there a spot where I can pull off the still-CFA encoded data but having run say black level and color scaling? Or, should I just:
unpack()
subtract_black()
scale_colors()
raw2image()
and find CFA data then from RawProcessor.imgdata.image[r*RAW_S.iwidth+c][RawProcessor.FC(r,c)]
Hi Alex,
Thanks for replying!
I actually used the conversion to "ushort *" right after posting the question. It seemed to work fine.
Have a nice day!
Mio
LibRaw is internally 16-bit unsigned int, so float conversion looks useless.
For 16-bit output just use explicit type conversion to (ushort*) for libraw_processed_image_t->data.
Thanks for quick response, I will try that.
In last master snapshot (https://github.com/LibRaw/LibRaw) we've added open_bayer() call
Look into: https://github.com/LibRaw/LibRaw/blob/master/Changelog.txt for docs
and into https://github.com/LibRaw/LibRaw/blob/master/samples/openbayer_sample.cpp for usage sample
There are as-shot WB coefficients (so diagonal adaptation matrix)
Awesome, thank you very much!
Jan
From dcraw_emu, usage() call:
"-w Use camera white balance, if possible\n"
And, sure, it works.
There is no -d/-D keys in dcraw_emu
Use unprocessed_raw sample instead.
Yes, you can set custom WB via user_mul. But for wrong WB demosaic results may be not good as expected.
dcraw_emu -o 0 -h works for me
(-o 0 translates to output_color=0, -h translates to half_size-1)
Hi Alex,
From what you said, it seems like the "white balance" is necessary before normal demosaic. If a user want to supply her/his own white balance factors, it can still be done through "user_mul[i]", correct?
Also, when I use "output_color = 0" and "half_size = 1" together (regardless other parameter), the image seems to look strange. Can you take a look at it?
Thanks so much and have a nice day!
Normal demosaic (not 'half' or 'linear interpolation') is useless without white balance first.
Hi Alex,
I would like to use the RAW data without calling "dcraw_mem_image()"; however, there is still a need for demosaic. Currently, I have to use "dcraw_mem_image()" with the parameters listed before to get it as close as possible.
If there is a function that I can call to get the image data that only goes through demosaic step (with no other adjustment), that would be great!
Thanks,
I'm still cannot understand what kind of data you need. You wrote 'close to', but could you please describe what you really need?
What is 'converted image'? imgdata.image array, or result of dcraw_mem_image() call?
Hi Alex,
"Unaltered image" is something close to what I am interested. Given the parameters that I enlisted, do they look reasonable to get the "Unaltered image"?
Also, only if you have time, would you mind replicating my test by adding "half_size = 1" (see below) and see if the converted image looks correct?
-----------------------------------------
use_camera_matrix = 0;
highlight = 0;
use_camera_wb = 0;
output_color = 0;
gamm[0] = 1.0; gamm[1] = 1.0;
no_auto_bright = 1;
user_mul[0] = 1.0; user_mul[1] = 1.0; user_mul[2] = 1.0;
half_size = 1;
-----------------------------------------
Thanks a lot!
I can not understand what 'demosaic RAW' is.
If you just need 'source' (unaltered) values from sensor/raw file, it is much better to access imgdata.rawdata.raw_image directly.
dcraw_process() means multiple processing stages. Your parameters looks like you need unaltered image.
Hi Alex,
Thank you for the quick reply! Appreciate it!
I understand there are several steps if dcraw_process () is called. Since I am interested in getting the image data that is very close to the "demosaic RAW", I manually set some parameter to "avoid" unnecessary processing on the RGB code values. For example, I did the following:
-----------------------------------------
use_camera_matrix = 0;
highlight = 0;
use_camera_wb = 0;
output_color = 0;
gamm[0] = 1.0; gamm[1] = 1.0;
no_auto_bright = 1;
user_mul[0] = 1.0; user_mul[1] = 1.0; user_mul[2] = 1.0;
-----------------------------------------
If the setting sounds reasonable, when I add "half_size=1", the converted image looks like a channel is missing.
Thanks a lot!
I did not understand exactly what you want
Standard raw processing sequence is (for decoded/linearized data) in dcraw_process is
- black subtraction
- white balance
- demosaic
- data scaling to use full range
- conversion to output color space
Than, on output
- brightness correction
- gamma curve
What stages do you need and what is not?
BTW, besides demosaic, all other steps are trivial and very easy to implement.
Thanks a lot for the quick reply!
I meant the "raw image data" that only has demosaic process. In this case, I may still need "dcraw_process", right? if it is, then when I use "output_color = 0" and "half_size = 1", the output seems like missing a channel.
Have a great day!
To get fully unprocessed raw data you may
1) Access imgdata.rawimage.raw_data array which stores raw values read from sensor as is
2) set params.half_size=1 and call raw2image() after unpack (instead of dcraw_process).
raw2image will arrange raw_data to imgdata.image[][4] array
Hi,
Thanks for the quick response!
I tried to use "output_color = 0" and "half_size = 1" at the same time, the output looks like a channel is missing.
Is there a way that I can have a unprocessed raw in half size? Perhaps I am unaware of something?
Thanks a lot,
We assume that someone who uses 'parts' of dcraw_process() will subclass LibRaw :)
Nice and thanks! I think the only issue for having this be a general solution (and not just having me rework the source a touch - fine for me, but...) is that scale_colors is protected rather than public.
unpack() is affected by camera_wb only in some (very rare) cases (I can not remember the details, it affects very small set of cameras, may be old Kodaks and/or foveon /old ones, before Sigma Merill).
For modern cameras unpack is not affected by color setting (but default for 'use_camera_matrix' for some cameras depends on wb settings)
subtract_black and scale_colors works with image[][4] array, so you need to call raw2image() before subtract_black().
Also, there is single call for raw2image and subtract_black:
int LibRaw::raw2image_ex(int do_subtract_black);
So:
open_file()
unpack();
raw2image_ex(1);
scale_colors();
will put black-subtracted and white-balanced image in image[][4]
Alex,
Thank you for all the details! I've been using:
RawProcessor.raw2image()
CFA data then from RawProcessor.imgdata.image[r*RAW_S.iwidth+c][RawProcessor.FC(r,c)]
in my code since ... well, a long time ago... to extract the unprocessed data for Bayer-matrix data. (The idea being, I do my own hot pixel / bad pixel mapping -- this is astrophotography work). When non-Bayer, I run:
RawProcessor.dcraw_process();
red data then from RawProcessor.imgdata.image[r*RAW_S.iwidth+c][0]
green from[1], blue from [2]
I poked around in the debugger and docs last night but still couldn't see the effect of use_camera_wb. The docs (http://www.libraw.org/docs/API-notes.html#imgdata_params) say that unpack() is affected by this but no matter what the setting, the output of raw2image() seems the same.
For Bayer matrices, is there a spot where I can pull off the still-CFA encoded data but having run say black level and color scaling? Or, should I just:
unpack()
subtract_black()
scale_colors()
raw2image()
and find CFA data then from RawProcessor.imgdata.image[r*RAW_S.iwidth+c][RawProcessor.FC(r,c)]
Craig
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