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enhanced shadows/highlights to avoid halos and desaturation

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- use a guided filter instead of Gaussian blur for computing the masks
- operate in RGB space instead of L*a*b* to retain saturation in the shadows
This commit is contained in:
Alberto Griggio
2018-10-03 15:11:40 +02:00
parent 67adaeb0e2
commit 17e4f6f25c
1 changed files with 59 additions and 47 deletions
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106
rtengine/ipshadowshighlights.cc
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@@ -22,6 +22,7 @@
#include "gauss.h"
#include "sleef.c"
#include "opthelper.h"
#include "guidedfilter.h"
namespace rtengine {
@@ -35,9 +36,29 @@ void ImProcFunctions::shadowsHighlights(LabImage *lab)
const int height = lab->H;
array2D<float> mask(width, height);
const float sigma = params->sh.radius * 5.f / scale;
LUTf f(32768);
array2D<float> L(width, height);
const float radius = float(params->sh.radius) * 10 / scale;
LUTf f(65536);
TMatrix ws = ICCStore::getInstance()->workingSpaceMatrix(params->icm.workingProfile);
TMatrix iws = ICCStore::getInstance()->workingSpaceInverseMatrix(params->icm.workingProfile);
const auto rgb2lab =
[&](float R, float G, float B, float &l, float &a, float &b) -> void
{
float x, y, z;
Color::rgbxyz(R, G, B, x, y, z, ws);
Color::XYZ2Lab(x, y, z, l, a, b);
};
const auto lab2rgb =
[&](float l, float a, float b, float &R, float &G, float &B) -> void
{
float x, y, z;
Color::Lab2XYZ(l, a, b, x, y, z);
Color::xyz2rgb(x, y, z, R, G, B, iws);
};
const auto apply =
[&](int amount, int tonalwidth, bool hl) -> void
{
@@ -45,27 +66,24 @@ void ImProcFunctions::shadowsHighlights(LabImage *lab)
const float scale = hl ? (thresh > 0.f ? 0.9f / thresh : 1.f) : thresh * 0.9f;
#ifdef _OPENMP
#pragma omp parallel if (multiThread)
#pragma omp parallel for if (multiThread)
#endif
{
#ifdef _OPENMP
#pragma omp for
#endif
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
float l = lab->L[y][x];
if (hl) {
mask[y][x] = (l > thresh) ? 1.f : pow4(l * scale);
} else {
mask[y][x] = l <= thresh ? 1.f : pow4(scale / l);
}
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
float l = lab->L[y][x];
float l1 = l / 32768.f;
if (hl) {
mask[y][x] = (l > thresh) ? 1.f : pow4(l * scale);
L[y][x] = 1.f - l1;
} else {
mask[y][x] = l <= thresh ? 1.f : pow4(scale / l);
L[y][x] = l1;
}
}
gaussianBlur(mask, mask, width, height, sigma);
}
guidedFilter(L, mask, mask, radius, 0.075, multiThread, 4);
const float base = std::pow(4.f, float(amount)/100.f);
const float gamma = hl ? base : 1.f / base;
@@ -83,32 +101,30 @@ void ImProcFunctions::shadowsHighlights(LabImage *lab)
#ifdef _OPENMP
#pragma omp parallel for if (multiThread)
#endif
for (int l = 0; l < 32768; ++l) {
for (int c = 0; c < 65536; ++c) {
float l, a, b;
float R = c, G = c, B = c;
rgb2lab(R, G, B, l, a, b);
auto base = pow_F(l / 32768.f, gamma);
// get a bit more contrast in the shadows
base = sh_contrast.getVal(base);
f[l] = base * 32768.f;
l = base * 32768.f;
lab2rgb(l, a, b, R, G, B);
f[c] = G;
}
} else {
#ifdef __SSE2__
vfloat c32768v = F2V(32768.f);
vfloat lv = _mm_setr_ps(0,1,2,3);
vfloat fourv = F2V(4.f);
vfloat gammav = F2V(gamma);
for (int l = 0; l < 32768; l += 4) {
vfloat basev = pow_F(lv / c32768v, gammav);
STVFU(f[l], basev * c32768v);
lv += fourv;
}
#else
#ifdef _OPENMP
#pragma omp parallel for if (multiThread)
#endif
for (int l = 0; l < 32768; ++l) {
for (int c = 0; c < 65536; ++c) {
float l, a, b;
float R = c, G = c, B = c;
rgb2lab(R, G, B, l, a, b);
auto base = pow_F(l / 32768.f, gamma);
f[l] = base * 32768.f;
l = base * 32768.f;
lab2rgb(l, a, b, R, G, B);
f[c] = G;
}
#endif
}
#ifdef _OPENMP
@@ -116,30 +132,26 @@ void ImProcFunctions::shadowsHighlights(LabImage *lab)
#endif
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
float l = lab->L[y][x];
float blend = mask[y][x];
float blend = LIM01(mask[y][x]);
float orig = 1.f - blend;
if (l >= 0.f && l < 32768.f) {
lab->L[y][x] = f[l] * blend + l * orig;
if (!hl && l > 1.f) {
// when pushing shadows, scale also the chromaticity
float s = max(lab->L[y][x] / l * 0.5f, 1.f) * blend;
float a = lab->a[y][x];
float b = lab->b[y][x];
lab->a[y][x] = a * s + a * orig;
lab->b[y][x] = b * s + b * orig;
if (lab->L[y][x] >= 0.f && lab->L[y][x] < 32768.f) {
float rgb[3];
lab2rgb(lab->L[y][x], lab->a[y][x], lab->b[y][x], rgb[0], rgb[1], rgb[2]);
for (int i = 0; i < 3; ++i) {
rgb[i] = f[rgb[i]] * blend + rgb[i] * orig;
}
rgb2lab(rgb[0], rgb[1], rgb[2], lab->L[y][x], lab->a[y][x], lab->b[y][x]);
}
}
}
};
if (params->sh.highlights > 0) {
apply(params->sh.highlights, params->sh.htonalwidth, true);
apply(params->sh.highlights * 0.7, params->sh.htonalwidth, true);
}
if (params->sh.shadows > 0) {
apply(params->sh.shadows, params->sh.stonalwidth, false);
apply(params->sh.shadows * 0.6, params->sh.stonalwidth, false);
}
}