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rawTherapee/rtengine/ipdehaze.cc
2019-09-19 20:56:33 +02:00

352 lines
12 KiB
C++

/* -*- C++ -*-
*
* This file is part of RawTherapee.
*
* Copyright (c) 2018 Alberto Griggio <alberto.griggio@gmail.com>
*
* RawTherapee is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* RawTherapee is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with RawTherapee. If not, see <https://www.gnu.org/licenses/>.
*/
/*
* Haze removal using the algorithm described in the paper:
*
* Single Image Haze Removal Using Dark Channel Prior
* by He, Sun and Tang
*
* using a guided filter for the "soft matting" of the transmission map
*
*/
#include <iostream>
#include <queue>
#include "guidedfilter.h"
#include "improcfun.h"
#include "procparams.h"
#include "rt_algo.h"
#include "rt_algo.h"
#include "rt_math.h"
#define BENCHMARK
#include "StopWatch.h"
extern Options options;
namespace rtengine {
namespace {
int get_dark_channel(const array2D<float> &R, const array2D<float> &G, const array2D<float> &B, array2D<float> &dst, int patchsize, const float ambient[3], bool clip, bool multithread, float strength)
{
const int W = R.width();
const int H = R.height();
#ifdef _OPENMP
#pragma omp parallel for if (multithread)
#endif
for (int y = 0; y < H; y += patchsize) {
const int pH = min(y + patchsize, H);
for (int x = 0; x < W; x += patchsize) {
float val = RT_INFINITY_F;
const int pW = min(x + patchsize, W);
for (int xx = x; xx < pW; ++xx) {
for (int yy = y; yy < pH; ++yy) {
val = min(val, R[yy][xx] / ambient[0], G[yy][xx] / ambient[1], B[yy][xx] / ambient[2]);
}
}
val = 1.f - strength * LIM01(val);
for (int yy = y; yy < pH; ++yy) {
std::fill(dst[yy] + x, dst[yy] + pW, val);
}
}
}
return (W / patchsize + ((W % patchsize) > 0)) * (H / patchsize + ((H % patchsize) > 0));
}
int get_dark_channel_downsized(const array2D<float> &R, const array2D<float> &G, const array2D<float> &B, array2D<float> &dst, int patchsize, bool multithread)
{
const int W = R.width();
const int H = R.height();
#ifdef _OPENMP
#pragma omp parallel for if (multithread)
#endif
for (int y = 0; y < H; y += patchsize) {
int yy = y / patchsize;
const int pH = min(y + patchsize, H);
for (int x = 0, xx = 0; x < W; x += patchsize, ++xx) {
float val = RT_INFINITY_F;
const int pW = min(x + patchsize, W);
for (int xp = x; xp < pW; ++xp) {
for (int yp = y; yp < pH; ++yp) {
val = min(val, R[yp][xp], G[yp][xp], B[yp][xp]);
}
}
dst[yy][xx] = val;
}
}
return (W / patchsize + ((W % patchsize) > 0)) * (H / patchsize + ((H % patchsize) > 0));
}
float estimate_ambient_light(const array2D<float> &R, const array2D<float> &G, const array2D<float> &B, const array2D<float> &dark, int patchsize, int npatches, float ambient[3])
{
const int W = R.width();
const int H = R.height();
float darklim = RT_INFINITY_F;
{
std::vector<float> p;
for (int y = 0, yy = 0; y < H; y += patchsize, ++yy) {
for (int x = 0, xx = 0; x < W; x += patchsize, ++xx) {
if (!OOG(dark[yy][xx], 1.f - 1e-5f)) {
p.push_back(dark[yy][xx]);
}
}
}
const int pos = p.size() * 0.95;
std::nth_element(p.begin(), p.begin() + pos, p.end());
darklim = p[pos];
}
std::vector<std::pair<int, int>> patches;
patches.reserve(npatches);
for (int y = 0, yy = 0; y < H; y += patchsize, ++yy) {
for (int x = 0, xx = 0; x < W; x += patchsize, ++xx) {
if (dark[yy][xx] >= darklim && !OOG(dark[yy][xx], 1.f)) {
patches.push_back(std::make_pair(x, y));
}
}
}
if (options.rtSettings.verbose) {
std::cout << "dehaze: computing ambient light from " << patches.size()
<< " patches" << std::endl;
}
float bright_lim = RT_INFINITY_F;
{
std::vector<float> l;
l.reserve(patches.size() * patchsize * patchsize);
for (const auto &p : patches) {
const int pW = min(p.first + patchsize, W);
const int pH = min(p.second + patchsize, H);
for (int y = p.second; y < pH; ++y) {
for (int x = p.first; x < pW; ++x) {
l.push_back(R[y][x] + G[y][x] + B[y][x]);
}
}
}
const int pos = l.size() * 0.95;
std::nth_element(l.begin(), l.begin() + pos, l.end());
bright_lim = l[pos];
}
double rr = 0, gg = 0, bb = 0;
int n = 0;
#ifdef _OPENMP
#pragma omp parallel for schedule(dynamic) reduction(+:rr,gg,bb,n)
#endif
for (const auto &p : patches) {
const int pW = min(p.first + patchsize, W);
const int pH = min(p.second + patchsize, H);
for (int y = p.second; y < pH; ++y) {
for (int x = p.first; x < pW; ++x) {
const float r = R[y][x];
const float g = G[y][x];
const float b = B[y][x];
if (r + g + b >= bright_lim) {
rr += r;
gg += g;
bb += b;
++n;
}
}
}
}
n = std::max(n, 1);
ambient[0] = rr / n;
ambient[1] = gg / n;
ambient[2] = bb / n;
// taken from darktable
return darklim > 0 ? -1.125f * std::log(darklim) : std::log(std::numeric_limits<float>::max()) / 2;
}
void extract_channels(Imagefloat *img, array2D<float> &r, array2D<float> &g, array2D<float> &b, int radius, float epsilon, bool multithread)
{
const int W = img->getWidth();
const int H = img->getHeight();
array2D<float> imgR(W, H, img->r.ptrs, ARRAY2D_BYREFERENCE);
guidedFilter(imgR, imgR, r, radius, epsilon, multithread);
array2D<float> imgG(W, H, img->g.ptrs, ARRAY2D_BYREFERENCE);
guidedFilter(imgG, imgG, g, radius, epsilon, multithread);
array2D<float> imgB(W, H, img->b.ptrs, ARRAY2D_BYREFERENCE);
guidedFilter(imgB, imgB, b, radius, epsilon, multithread);
}
} // namespace
void ImProcFunctions::dehaze(Imagefloat *img)
{
if (!params->dehaze.enabled || params->dehaze.strength == 0.0) {
return;
}
BENCHFUN
img->normalizeFloatTo1();
const int W = img->getWidth();
const int H = img->getHeight();
const float strength = LIM01(float(params->dehaze.strength) / 100.f * 0.9f);
if (options.rtSettings.verbose) {
std::cout << "dehaze: strength = " << strength << std::endl;
}
array2D<float> dark(W, H);
int patchsize = max(int(5 / scale), 2);
float ambient[3];
float max_t = 0.f;
{
array2D<float> R(W, H);
array2D<float> G(W, H);
array2D<float> B(W, H);
extract_channels(img, R, G, B, patchsize, 1e-1, multiThread);
patchsize = max(max(W, H) / 600, 2);
array2D<float> darkDownsized(W / patchsize + 1, H / patchsize + 1);
const int npatches = get_dark_channel_downsized(R, G, B, darkDownsized, patchsize, multiThread);
max_t = estimate_ambient_light(R, G, B, darkDownsized, patchsize, npatches, ambient);
if (options.rtSettings.verbose) {
std::cout << "dehaze: ambient light is "
<< ambient[0] << ", " << ambient[1] << ", " << ambient[2]
<< std::endl;
}
if (min(ambient[0], ambient[1], ambient[2]) < 0.01f) {
if (options.rtSettings.verbose) {
std::cout << "dehaze: no haze detected" << std::endl;
}
img->normalizeFloatTo65535();
return; // probably no haze at all
}
get_dark_channel(R, G, B, dark, patchsize, ambient, true, multiThread, strength);
}
const int radius = patchsize * 4;
constexpr float epsilon = 1e-5f;
{
array2D<float> guideB(W, H, img->b.ptrs, ARRAY2D_BYREFERENCE);
guidedFilter(guideB, dark, dark, radius, epsilon, multiThread);
}
if (options.rtSettings.verbose) {
std::cout << "dehaze: max distance is " << max_t << std::endl;
}
const float depth = -float(params->dehaze.depth) / 100.f;
const float t0 = max(1e-3f, std::exp(depth * max_t));
const float teps = 1e-3f;
#ifdef _OPENMP
#pragma omp parallel for if (multiThread)
#endif
for (int y = 0; y < H; ++y) {
int x = 0;
#ifdef __SSE2__
const vfloat onev = F2V(1.f);
const vfloat ambient0v = F2V(ambient[0]);
const vfloat ambient1v = F2V(ambient[1]);
const vfloat ambient2v = F2V(ambient[2]);
const vfloat t0v = F2V(t0);
const vfloat tepsv = F2V(teps);
const vfloat c65535v = F2V(65535.f);
for (; x < W - 3; x += 4) {
// ensure that the transmission is such that to avoid clipping...
vfloat r = LVFU(img->r(y, x));
vfloat g = LVFU(img->g(y, x));
vfloat b = LVFU(img->b(y, x));
// ... t >= tl to avoid negative values
const vfloat tlv = onev - vminf(r / ambient0v, vminf(g / ambient1v, b / ambient2v));
// ... t >= tu to avoid values > 1
r -= ambient0v;
g -= ambient1v;
b -= ambient2v;
vfloat tuv = t0v - tepsv;
tuv = vself(vmaskf_lt(ambient0v, onev), vmaxf(tuv, r / (onev - ambient0v)), tuv);
tuv = vself(vmaskf_lt(ambient1v, onev), vmaxf(tuv, g / (onev - ambient1v)), tuv);
tuv = vself(vmaskf_lt(ambient2v, onev), vmaxf(tuv, b / (onev - ambient2v)), tuv);
const vfloat mtv = vmaxf(LVFU(dark[y][x]), vmaxf(tlv, tuv) + tepsv);
if (params->dehaze.showDepthMap) {
const vfloat valv = vclampf(onev - mtv, ZEROV, onev) * c65535v;
STVFU(img->r(y, x), valv);
STVFU(img->g(y, x), valv);
STVFU(img->b(y, x), valv);
} else {
STVFU(img->r(y, x), (r / mtv + ambient0v) * c65535v);
STVFU(img->g(y, x), (g / mtv + ambient1v) * c65535v);
STVFU(img->b(y, x), (b / mtv + ambient2v) * c65535v);
}
}
#endif
for (; x < W; ++x) {
// ensure that the transmission is such that to avoid clipping...
float r = img->r(y, x);
float g = img->g(y, x);
float b = img->b(y, x);
// ... t >= tl to avoid negative values
const float tl = 1.f - min(r / ambient[0], g / ambient[1], b / ambient[2]);
// ... t >= tu to avoid values > 1
r -= ambient[0];
g -= ambient[1];
b -= ambient[2];
float tu = t0 - teps;
tu = ambient[0] < 1.f ? max(tu, r / (1.f - ambient[0])) : tu;
tu = ambient[1] < 1.f ? max(tu, g / (1.f - ambient[1])) : tu;
tu = ambient[2] < 1.f ? max(tu, b / (1.f - ambient[2])) : tu;
const float mt = max(dark[y][x], tl + teps, tu + teps);
if (params->dehaze.showDepthMap) {
img->r(y, x) = img->g(y, x) = img->b(y, x) = LIM01(1.f - mt) * 65535.f;
} else {
img->r(y, x) = (r / mt + ambient[0]) * 65535.f;
img->g(y, x) = (g / mt + ambient[1]) * 65535.f;
img->b(y, x) = (b / mt + ambient[2]) * 65535.f;
}
}
}
}
} // namespace rtengine