User defined custom white balance

Submitted by David Partridge on

I am processing an image from an X-Trans sensor (not a normal CFA). If I set user_mul to {1.0, 1.0, 1.0, 1.0} shouldn't the code use these values as the WB co-efficients, or did I miss something else I need to set to make the code use a user defined WB?

Certainly the output image appears identical to the daylight WB case.

Thanks
David

Forums: 

They not only look identical,

Submitted by David Partridge on

They not only look identical, they are identical:

D:\Users\amonra\Documents\Astrophotography\DSS Test Images>dcraw_emu -v -v -r 1.0 1.0 1.0 1.0 "DSCF3954(X-Trans).RAF"
Processing file DSCF3954(X-Trans).RAF
Reading metadata finished
Starting Reading RAW data (expecting 2 iterations)
Reading RAW data finished
Starting Scaling colors (expecting 2 iterations)
Scaling colors finished
Starting Pre-interpolating (expecting 2 iterations)
Pre-interpolating finished
Starting Converting to RGB (expecting 2 iterations)
Converting to RGB finished
Writing file DSCF3954(X-Trans).RAF.ppm

D:\Users\amonra\Documents\Astrophotography\DSS Test Images>rename "DSCF3954(X-Trans).RAF.ppm" "DSCF3954(X-Trans).RAF.NoWB.ppm"

D:\Users\amonra\Documents\Astrophotography\DSS Test Images>dcraw_emu -v -v "DSCF3954(X-Trans).RAF"
Processing file DSCF3954(X-Trans).RAF
Reading metadata finished
Starting Reading RAW data (expecting 2 iterations)
Reading RAW data finished
Starting Scaling colors (expecting 2 iterations)
Scaling colors finished
Starting Pre-interpolating (expecting 2 iterations)
Pre-interpolating finished
Starting Converting to RGB (expecting 2 iterations)
Converting to RGB finished
Writing file DSCF3954(X-Trans).RAF.ppm

D:\Users\amonra\Documents\Astrophotography\DSS Test Images>fc "DSCF3954(X-Trans).RAF.NoWB.ppm" "DSCF3954(X-Trans).RAF.ppm"
Comparing files DSCF3954(X-Trans).RAF.NoWB.ppm and DSCF3954(X-TRANS).RAF.PPM
FC: no differences encountered

D:\Users\amonra\Documents\Astrophotography\DSS Test Images>

David Partridge

OK I now understand what's

Submitted by David Partridge on

OK I now understand what's happening:

>raw-identify -v "DSCF3954(X-Trans).RAF"

Filename: DSCF3954(X-Trans).RAF
Timestamp: Sat Oct 6 15:56:45 2018
Camera: Fujifilm X-T3 ID: 0x0
Body serial: 8CQ04794
Owner:
:
: stuff deleted
:
Filter pattern: GGGGBRGGGGRBGGGG
Makernotes 'As shot' WB multipliers: 563.000000 302.000000 531.000000 0.000000
Makernotes 'Tungsten' WB multipliers: 367 302 818 302
Makernotes 'Fine Weather' WB multipliers: 546 302 539 302
Makernotes 'Shade' WB multipliers: 595 302 462 302
Makernotes 'Daylight Fluorescent D' WB multipliers: 701 302 471 302
Makernotes 'Cool White Fluorescent W' WB multipliers: 571 302 736 302
Makernotes 'Warm White Fluorescent L' WB multipliers: 596 302 585 302
Makernotes 'Illuminant A' WB multipliers: 367 302 818 302
Makernotes 'D65' WB multipliers: 623 302 476 302
Makernotes 'Camera Auto' WB multipliers: 563 302 531 302
Camera2RGB matrix:
1.0000 0.0000 0.0000
0.0000 1.0000 0.0000
0.0000 0.0000 1.0000

XYZ->CamRGB matrix:
0.0000 0.0000 0.0000
0.0000 0.0000 0.0000
0.0000 0.0000 0.0000

Derived D65 multipliers: 1.000000 1.000000 1.000000

Notice the last line above ...

I know that 0.19.3 doesn't officially support the X-T3, but I think the code could attempt to default to calculating the D65 co-efficients instead of setting them to 1.0.

I am happy that it is working as I expected with a raw file from an X-T1!

>raw-identify -v _DSF3925.RAF

Filename: _DSF3925.RAF
Timestamp: Wed Mar 15 20:56:39 2017
Camera: Fujifilm X-T1 ID: 0x0

: Stuff deleted.

Makernotes 'As shot' WB multipliers: 581.000000 302.000000 468.000000 0.000000
Makernotes 'Tungsten' WB multipliers: 389 302 686 302
Makernotes 'Fine Weather' WB multipliers: 581 302 468 302
Makernotes 'Shade' WB multipliers: 642 302 401 302
Makernotes 'Daylight Fluorescent D' WB multipliers: 735 302 410 302
Makernotes 'Cool White Fluorescent W' WB multipliers: 598 302 619 302
Makernotes 'Warm White Fluorescent L' WB multipliers: 622 302 485 302
Makernotes 'Illuminant A' WB multipliers: 389 302 686 302
Makernotes 'D65' WB multipliers: 665 302 406 302
Makernotes 'Camera Auto' WB multipliers: 590 302 468 302
Camera2RGB matrix:
1.6442 -0.5539 -0.0904
-0.1896 1.6455 -0.4559
0.0505 -0.5409 1.4904

XYZ->CamRGB matrix:
0.8458 -0.2451 -0.0855
-0.4597 1.2447 0.2407
-0.1475 0.2482 0.6526

Derived D65 multipliers: 2.147247 0.934710 1.221633

Sorry if this has been a bother.
David

David Partridge

Dear Sir:

Submitted by ib on

Dear Sir:

"Notice the last line above"

You can either use the numbers from "Makernotes 'D65' WB multipliers: 665 302 406 302" line which is also above; or you may want to familiarize yourself with the procedure that results in calculation of "Derived D65 multipliers" and insert a CM2 into your copy of LibRaw.

"the code could attempt to default to calculating the D65 co-efficients instead of setting them to 1.0." is uncalled for.

--
Iliah Borg

Why is that uncalled for? I

Submitted by David Partridge on

Why is that uncalled for? Given that those multipliers are clearly used to set the default pre_mul, that seemed like a sensible suggestion to me. There was no criticism.

David

David Partridge

Dear Sir:

Submitted by ib on

Dear Sir:
Criticism is welcome, that's how we improve.
"Uncalled for" also means "unnecessary" and "unfair". Everything was right in front of you, please pay attention.
I'm not going to continue this discussion, let's stick to questions and answers that are relevant.

--
Iliah Borg

Huh - I totally do not

Submitted by David Partridge on

I tried to find the code that sets pre_mull from the d65 coefficients and totally failed. Where is it please?

David Partridge

Iliah, please will you bear

Submitted by David Partridge on

Iliah, please will you bear with me. I've just spent a whole day chasing this problem.

I *still* don't understand why pre_mul was set to 1.0, 1.0, 1.0 for the Fuji X-T3, but was set to relevant values based on the D65 Illimunant White Balance values for the X-T1.

I had already searched the code looking for everywhere that pre_mul[] values are set and for the life of me I couldn't find the code that converts the WB_Coeffs to the pre_mul values. OK you may think I am stupid, but please I'm looking for assistance here, not a pointer the annotated DCRaw code.

David Partridge

Dear Sir:

Submitted by ib on

Dear Sir:

The camera is not supported in the LibRaw version you are using, that's why the derived pre-muls for daylight are not available. If you want to support it instead of waiting for the next release, you need to spend some time familiarizing yourself with the code. The link I've provided above should be very helpful.

--
Iliah Borg

I have to say that I don't

Submitted by David Partridge on

I have to say that I don't understand your approach to my enquiry. Why are you not providing me with a helpful explanation of what is happening here, rather than just pointing me to the source code and say "go figure it out yourself". I have to question the point of having a LibRaw support forum here if the people who know the code won't explain why something isn't working in the way that someone trying to use it expected.

I was already aware of the annotated DCRaw web-site and have been there a number of times. On this occasion however I am still completely in the dark as to quite where in the LibRaw code the pre_mul value is set from the White Balance Coefficients, and very specifically I don't understand quite why pre_mul was set to values of 1.0 for the unsupported X-T3, but was set to useful values for the X-T1.

I don't want to add support for the camera in question to libraw in the current release. I realise that it will very likely be supported in the 0.20.? release as I believe it is already supported in the snapshots.

David Partridge

Dear Sir:

Submitted by ib on

Dear Sir:

> Why are you not providing me with a helpful explanation of what is happening here
> a helpful explanation

The camera is not supported in the version you are using, right? So, what do you expect to be helpful? I'm at loss, since "CM2" obviously means very little to you.

> where in the LibRaw code the pre_mul value is set from the White Balance Coefficients

What does search for pre_mul return?

--
Iliah Borg

Yes, I totally understand its

Submitted by David Partridge on

Yes, I totally understand its not supported in the current release, but it would nonetheless be very helpful to me if you could provide some understanding of how your code works in this area.

You are correct CM2 means nothing to me at all.

   \libraw\libraw.h(104):  DllDef float libraw_get_pre_mul(libraw_data_t *lr, int index);
  \libraw\libraw_types.h(481):    float pre_mul[4];
  \internal\var_defines.h(61):#define pre_mul         (imgdata.color.pre_mul)
  \internal\dcraw_common.cpp(413):    pre_mul[i - 1] = 1 / (frac * mul[hi][i] + (1 - frac) * mul[lo][i]);
  \internal\dcraw_common.cpp(510):      pre_mul[i] = 1.0 / (total[st][i] + total[st][i + 4]);
  \internal\dcraw_common.cpp(525):  mc = pre_mul[1] / pre_mul[2];
  \internal\dcraw_common.cpp(526):  yc = pre_mul[3] / pre_mul[2];
  \internal\dcraw_common.cpp(4847):      pre_mul[i] = 1 / num;
  \internal\dcraw_common.cpp(4853):      pre_mul[i] = 1.0;
  \internal\dcraw_common.cpp(4925):    FORCC balance[geshifilter-c] = pre_mul[c] * gmb_cam[20][c];
  \internal\dcraw_common.cpp(5016):      mul[row] = 0.125 * pre_mul[FC(row + 1, 0) | 1] / pre_mul[FC(row, 0) | 1];
  \internal\dcraw_common.cpp(5131):      mul[row] = 0.125 * pre_mul[FC(row + 1, 0) | 1] / pre_mul[FC(row, 0) | 1];
  \internal\dcraw_common.cpp(5236):    memcpy(pre_mul, user_mul, sizeof pre_mul);
  \internal\dcraw_common.cpp(5269):    FORC4 if (dsum[c]) pre_mul[c] = dsum[c + 4] / dsum[c];
  \internal\dcraw_common.cpp(5286):      pre_mul[0] = pre_mul[1] = pre_mul[2] = pre_mul[3] = 1.0;
  \internal\dcraw_common.cpp(5291):      FORC4 pre_mul[c] = (float)sum[c + 4] / sum[c];
  \internal\dcraw_common.cpp(5293):      memcpy(pre_mul, cam_mul, sizeof pre_mul);
  \internal\dcraw_common.cpp(5310):      pre_mul[c] /= cam_mul[c];
  \internal\dcraw_common.cpp(5313):  if (pre_mul[1] == 0)
  \internal\dcraw_common.cpp(5314):    pre_mul[1] = 1;
  \internal\dcraw_common.cpp(5315):  if (pre_mul[3] == 0)
  \internal\dcraw_common.cpp(5316):    pre_mul[3] = colors < 4 ? pre_mul[1] : 1;
  \internal\dcraw_common.cpp(5324):    if (dmin > pre_mul[c])
  \internal\dcraw_common.cpp(5325):      dmin = pre_mul[c];
  \internal\dcraw_common.cpp(5326):    if (dmax < pre_mul[c])
  \internal\dcraw_common.cpp(5327):      dmax = pre_mul[c];
  \internal\dcraw_common.cpp(5331):  FORC4 scale_mul[c] = (pre_mul[c] /= dmax) * 65535.0 / maximum;
  \internal\dcraw_common.cpp(5336):    FORC4 fprintf(stderr, " %f", pre_mul[c]);
  \internal\dcraw_common.cpp(6601):  FORCC if (clip > (i = 65535 * pre_mul[c])) clip = i;
  \internal\dcraw_common.cpp(6645):  FORCC hsat[c] = 32000 * pre_mul[c];
  \internal\dcraw_common.cpp(6647):    if (pre_mul[kc] < pre_mul[c])
  \internal\dcraw_common.cpp(14075):    FORCC if(fabs(cc[c][c])>0.0001) pre_mul[c] /= cc[c][c];
  \internal\dcraw_common.cpp(17758):    pre_mul[i] = i < 3;
  \internal\dcraw_common.cpp(18601):    pre_mul[0] = 1.2085;
  \internal\dcraw_common.cpp(18602):    pre_mul[1] = 1.0943;
  \internal\dcraw_common.cpp(18603):    pre_mul[3] = 1.1103;
  \internal\dcraw_common.cpp(18618):      pre_mul[0] = 1.196;
  \internal\dcraw_common.cpp(18619):      pre_mul[1] = 1.246;
  \internal\dcraw_common.cpp(18620):      pre_mul[2] = 1.018;
  \internal\dcraw_common.cpp(19341):      pre_mul[1] = 1.179;
  \internal\dcraw_common.cpp(19342):      pre_mul[2] = 1.209;
  \internal\dcraw_common.cpp(19343):      pre_mul[3] = 1.036;
  \src\libraw_c_api.cpp(387):  DllDef float libraw_get_pre_mul(libraw_data_t *lr, int index)
  \src\libraw_c_api.cpp(391):    return lr->color.pre_mul[LIM(index, 0, 3)];
  \src\libraw_cxx.cpp(1222):    imgdata.color.pre_mul[i] = 1.0;
  \src\libraw_cxx.cpp(2110):          imgdata.color.pre_mul[c] /= (delta[c] / maxdelta);
  \src\libraw_cxx.cpp(2148):      imgdata.color.pre_mul[0] = 1.f / 0.3984f;
  \src\libraw_cxx.cpp(2149):      imgdata.color.pre_mul[2] = 1.f / 0.7666f;
  \src\libraw_cxx.cpp(2150):      imgdata.color.pre_mul[1] = imgdata.color.pre_mul[3] = 1.0;
  \src\libraw_cxx.cpp(4048):      if (dmax > C.pre_mul[c])
  \src\libraw_cxx.cpp(4049):        dmax = C.pre_mul[c];
  \src\libraw_cxx.cpp(4052):      scale_mul[c] = (C.pre_mul[c] / dmax) * 65535.0 / C.maximum;
  Matching lines: 52    Matching files: 6    Total files searched: 16


in none of those places does there appear to be any derivation of the pre_mul value from the WB Coefficients, even though it is clear that such a derivation must take place.[/geshifilter-c]

David Partridge

Dear Sir:

Submitted by ib on

Dear Sir:

"in none of those places does there appear to be any derivation of the pre_mul
value from the WB Coefficients, even though it is clear that such a
derivation must take place."

No, it mustn't, unless WB coeffs are user-supplied.

--
Iliah Borg

I'm sorry but it appears frm

Submitted by David Partridge on

I'm sorry but it appears frm the output of raw-identify that the Libraw code has derived the pre_mul values from the D65 illuminant WB coefficents and other information returned in the raw file for the X-T1. I cannot see where else these

Derived D65 multipliers: 2.147247 0.934710 1.221633

values which are the contents of the pre_mul array could have come from (unless they are hard coded into LibRaw). A pre_mul array with all values set to 1.0 by LibRaw just doesn't make any sense for processing a raw fille for Daylight WB.

So again I ask you how is pre_mul set from the WB coefficients and other data read from the raw file, so I can better understand your code and maybe make contributions in the future.

David Partridge

D65 multipliers are pre-built

Submitted by lexa on

D65 multipliers are pre-built, so there is no daylight WB for unsupported cameras.

-- Alex Tutubalin @LibRaw LLC

Of course, one may use pre

Submitted by lexa on

Of course, one may use pre-set WBs if extracted from camera metadata.

-- Alex Tutubalin @LibRaw LLC

Does that mean that I could

Submitted by David Partridge on

Does that mean that I could ask Libraw to use (for example) the "Fine weather" white balance coefficients from the X-T1 raw file metadata Maker-notes?

How would I do that?

Thanks again

David Partridge

Aha! So, are those pre-built

Submitted by David Partridge on

Aha! So, are those pre-built values buried in the entries like:

{ "Fujifilm X-T1", 0, 0,
{ 8458,-2451,-855,-4597,12447,2407,-1475,2482,6526 } },

or if not where to find them in the code and how do they get propogated into pre_mul?

Many thanks
David

David Partridge

So this code:

Submitted by David Partridge on

So this code:

void CLASS cam_xyz_coeff(float _rgb_cam[3][4], double cam_xyz[4][3])
{
double cam_rgb[4][3], inverse[4][3], num;
int i, j, k;

for (i = 0; i < colors; i++) /* Multiply out XYZ colorspace */
for (j = 0; j < 3; j++)
for (cam_rgb[i][j] = k = 0; k < 3; k++)
cam_rgb[i][j] += cam_xyz[i][k] * xyz_rgb[k][j];

for (i = 0; i < colors; i++)
{ /* Normalize cam_rgb so that */
for (num = j = 0; j < 3; j++) /* cam_rgb * (1,1,1) is (1,1,1,1) */
num += cam_rgb[i][j];
if (num > 0.00001)
{
for (j = 0; j < 3; j++)
cam_rgb[i][j] /= num;
pre_mul[i] = 1 / num;
}

David Partridge

yes

Submitted by lexa on

yes

-- Alex Tutubalin @LibRaw LLC