diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/qcam/dng_writer.cpp | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/src/qcam/dng_writer.cpp b/src/qcam/dng_writer.cpp index 61505d38..8fb9681c 100644 --- a/src/qcam/dng_writer.cpp +++ b/src/qcam/dng_writer.cpp @@ -34,6 +34,97 @@ struct FormatInfo { unsigned int stride); }; +struct Matrix3d { + Matrix3d() + { + } + + Matrix3d(float m0, float m1, float m2, + float m3, float m4, float m5, + float m6, float m7, float m8) + { + m[0] = m0, m[1] = m1, m[2] = m2; + m[3] = m3, m[4] = m4, m[5] = m5; + m[6] = m6, m[7] = m7, m[8] = m8; + } + + Matrix3d(const Span<const float> &span) + : Matrix3d(span[0], span[1], span[2], + span[3], span[4], span[5], + span[6], span[7], span[8]) + { + } + + static Matrix3d diag(float diag0, float diag1, float diag2) + { + return Matrix3d(diag0, 0, 0, 0, diag1, 0, 0, 0, diag2); + } + + static Matrix3d identity() + { + return Matrix3d(1, 0, 0, 0, 1, 0, 0, 0, 1); + } + + Matrix3d transpose() const + { + return { m[0], m[3], m[6], m[1], m[4], m[7], m[2], m[5], m[8] }; + } + + Matrix3d cofactors() const + { + return { m[4] * m[8] - m[5] * m[7], + -(m[3] * m[8] - m[5] * m[6]), + m[3] * m[7] - m[4] * m[6], + -(m[1] * m[8] - m[2] * m[7]), + m[0] * m[8] - m[2] * m[6], + -(m[0] * m[7] - m[1] * m[6]), + m[1] * m[5] - m[2] * m[4], + -(m[0] * m[5] - m[2] * m[3]), + m[0] * m[4] - m[1] * m[3] }; + } + + Matrix3d adjugate() const + { + return cofactors().transpose(); + } + + float determinant() const + { + return m[0] * (m[4] * m[8] - m[5] * m[7]) - + m[1] * (m[3] * m[8] - m[5] * m[6]) + + m[2] * (m[3] * m[7] - m[4] * m[6]); + } + + Matrix3d inverse() const + { + return adjugate() * (1.0 / determinant()); + } + + Matrix3d operator*(const Matrix3d &other) const + { + Matrix3d result; + for (unsigned int i = 0; i < 3; i++) { + for (unsigned int j = 0; j < 3; j++) { + result.m[i * 3 + j] = + m[i * 3 + 0] * other.m[0 + j] + + m[i * 3 + 1] * other.m[3 + j] + + m[i * 3 + 2] * other.m[6 + j]; + } + } + return result; + } + + Matrix3d operator*(float f) const + { + Matrix3d result; + for (unsigned int i = 0; i < 9; i++) + result.m[i] = m[i] * f; + return result; + } + + float m[9]; +}; + void packScanlineSBGGR10P(void *output, const void *input, unsigned int width) { const uint8_t *in = static_cast<const uint8_t *>(input); @@ -316,6 +407,53 @@ int DNGWriter::write(const char *filename, const Camera *camera, TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT); /* + * Fill in some reasonable colour information in the DNG. We supply + * the "neutral" colour values which determine the white balance, and the + * "ColorMatrix1" which converts XYZ to (un-white-balanced) camera RGB. + * Note that this is not a "proper" colour calibration for the DNG, + * nonetheless, many tools should be able to render the colours better. + */ + float neutral[3] = { 1, 1, 1 }; + Matrix3d wbGain = Matrix3d::identity(); + /* From http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html */ + const Matrix3d rgb2xyz(0.4124564, 0.3575761, 0.1804375, + 0.2126729, 0.7151522, 0.0721750, + 0.0193339, 0.1191920, 0.9503041); + Matrix3d ccm = Matrix3d::identity(); + /* + * Pick a reasonable number eps to protect against singularities. It + * should be comfortably larger than the point at which we run into + * numerical trouble, yet smaller than any plausible gain that we might + * apply to a colour, either explicitly or as part of the colour matrix. + */ + const double eps = 1e-2; + + if (metadata.contains(controls::ColourGains)) { + Span<const float> const &colourGains = metadata.get(controls::ColourGains); + if (colourGains[0] > eps && colourGains[1] > eps) { + wbGain = Matrix3d::diag(colourGains[0], 1, colourGains[1]); + neutral[0] = 1.0 / colourGains[0]; /* red */ + neutral[2] = 1.0 / colourGains[1]; /* blue */ + } + } + if (metadata.contains(controls::ColourCorrectionMatrix)) { + Span<const float> const &coeffs = metadata.get(controls::ColourCorrectionMatrix); + Matrix3d ccmSupplied(coeffs); + if (ccmSupplied.determinant() > eps) + ccm = ccmSupplied; + } + + /* + * rgb2xyz is known to be invertible, and we've ensured above that both + * the ccm and wbGain matrices are non-singular, so the product of all + * three is guaranteed to be invertible too. + */ + Matrix3d colorMatrix1 = (rgb2xyz * ccm * wbGain).inverse(); + + TIFFSetField(tif, TIFFTAG_COLORMATRIX1, 9, colorMatrix1.m); + TIFFSetField(tif, TIFFTAG_ASSHOTNEUTRAL, 3, neutral); + + /* * Reserve space for the SubIFD and ExifIFD tags, pointing to the IFD * for the raw image and EXIF data respectively. The real offsets will * be set later. |