/src/FreeImage/Source/FreeImage/tmoDrago03.cpp
https://bitbucket.org/cabalistic/ogredeps/ · C++ · 295 lines · 166 code · 38 blank · 91 comment · 36 complexity · 122d9ef476c636a6137b8b9fcc664ada MD5 · raw file
- // ==========================================================
- // Tone mapping operator (Drago, 2003)
- //
- // Design and implementation by
- // - Hervé Drolon (drolon@infonie.fr)
- //
- // This file is part of FreeImage 3
- //
- // COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
- // OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
- // THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
- // OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
- // CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
- // THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
- // SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
- // PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
- // THIS DISCLAIMER.
- //
- // Use at your own risk!
- // ==========================================================
- #include "FreeImage.h"
- #include "Utilities.h"
- #include "ToneMapping.h"
- // ----------------------------------------------------------
- // Logarithmic mapping operator
- // Reference:
- // [1] F. Drago, K. Myszkowski, T. Annen, and N. Chiba,
- // Adaptive Logarithmic Mapping for Displaying High Contrast Scenes,
- // Eurographics 2003.
- // ----------------------------------------------------------
- /**
- Bias function
- */
- static inline double
- biasFunction(const double b, const double x) {
- return pow (x, b); // pow(x, log(bias)/log(0.5)
- }
- /**
- Padé approximation of log(x + 1)
- x(6+x)/(6+4x) good if x < 1
- x*(6 + 0.7662x)/(5.9897 + 3.7658x) between 1 and 2
- See http://www.nezumi.demon.co.uk/consult/logx.htm
- */
- static inline double
- pade_log(const double x) {
- if(x < 1) {
- return (x * (6 + x) / (6 + 4 * x));
- } else if(x < 2) {
- return (x * (6 + 0.7662 * x) / (5.9897 + 3.7658 * x));
- }
- return log(x + 1);
- }
- /**
- Log mapping operator
- @param dib Input / Output Yxy image
- @param maxLum Maximum luminance
- @param avgLum Average luminance (world adaptation luminance)
- @param biasParam Bias parameter (a zero value default to 0.85)
- @param exposure Exposure parameter (default to 0)
- @return Returns TRUE if successful, returns FALSE otherwise
- */
- static BOOL
- ToneMappingDrago03(FIBITMAP *dib, const float maxLum, const float avgLum, float biasParam, const float exposure) {
- const float LOG05 = -0.693147F; // log(0.5)
- double Lmax, divider, interpol, biasP;
- unsigned x, y;
- double L;
- if(FreeImage_GetImageType(dib) != FIT_RGBF)
- return FALSE;
- const unsigned width = FreeImage_GetWidth(dib);
- const unsigned height = FreeImage_GetHeight(dib);
- const unsigned pitch = FreeImage_GetPitch(dib);
- // arbitrary Bias Parameter
- if(biasParam == 0)
- biasParam = 0.85F;
- // normalize maximum luminance by average luminance
- Lmax = maxLum / avgLum;
-
- divider = log10(Lmax+1);
- biasP = log(biasParam)/LOG05;
- #if !defined(DRAGO03_FAST)
- /**
- Normal tone mapping of every pixel
- further acceleration is obtained by a Padé approximation of log(x + 1)
- */
- BYTE *bits = (BYTE*)FreeImage_GetBits(dib);
- for(y = 0; y < height; y++) {
- FIRGBF *pixel = (FIRGBF*)bits;
- for(x = 0; x < width; x++) {
- double Yw = pixel[x].red / avgLum;
- Yw *= exposure;
- interpol = log(2 + biasFunction(biasP, Yw / Lmax) * 8);
- L = pade_log(Yw);// log(Yw + 1)
- pixel[x].red = (float)((L / interpol) / divider);
- }
- // next line
- bits += pitch;
- }
- #else
- unsigned index;
- int i, j;
- unsigned max_width = width - (width % 3);
- unsigned max_height = height - (height % 3);
- unsigned fpitch = pitch / sizeof(FIRGBF);
- /**
- fast tone mapping
- split the image into 3x3 pixel tiles and perform the computation for each group of 9 pixels
- further acceleration is obtained by a Padé approximation of log(x + 1)
- => produce artifacts and not so faster, so the code has been disabled
- */
- #define PIXEL(x, y) image[y*fpitch + x].red
- FIRGBF *image = (FIRGBF*)FreeImage_GetBits(dib);
- for(y = 0; y < max_height; y += 3) {
- for(x = 0; x < max_width; x += 3) {
- double average = 0;
- for(i = 0; i < 3; i++) {
- for(j = 0; j < 3; j++) {
- index = (y + i)*fpitch + (x + j);
- image[index].red /= (float)avgLum;
- image[index].red *= exposure;
- average += image[index].red;
- }
- }
- average = average / 9 - PIXEL(x, y);
- if(average > -1 && average < 1) {
- interpol = log(2 + pow(PIXEL(x + 1, y + 1) / Lmax, biasP) * 8);
- for(i = 0; i < 3; i++) {
- for(j = 0; j < 3; j++) {
- index = (y + i)*fpitch + (x + j);
- L = pade_log(image[index].red);// log(image[index].red + 1)
- image[index].red = (float)((L / interpol) / divider);
- }
- }
- }
- else {
- for(i = 0; i < 3; i++) {
- for(j = 0; j < 3; j++) {
- index = (y + i)*fpitch + (x + j);
- interpol = log(2 + pow(image[index].red / Lmax, biasP) * 8);
- L = pade_log(image[index].red);// log(image[index].red + 1)
- image[index].red = (float)((L / interpol) / divider);
- }
- }
- }
- } //x
- } // y
- /**
- Normal tone mapping of every pixel for the remaining right and bottom bands
- */
- BYTE *bits;
- // right band
- bits = (BYTE*)FreeImage_GetBits(dib);
- for(y = 0; y < height; y++) {
- FIRGBF *pixel = (FIRGBF*)bits;
- for(x = max_width; x < width; x++) {
- double Yw = pixel[x].red / avgLum;
- Yw *= exposure;
- interpol = log(2 + biasFunction(biasP, Yw / Lmax) * 8);
- L = pade_log(Yw);// log(Yw + 1)
- pixel[x].red = (float)((L / interpol) / divider);
- }
- // next line
- bits += pitch;
- }
- // bottom band
- bits = (BYTE*)FreeImage_GetBits(dib);
- for(y = max_height; y < height; y++) {
- FIRGBF *pixel = (FIRGBF*)bits;
- for(x = 0; x < max_width; x++) {
- double Yw = pixel[x].red / avgLum;
- Yw *= exposure;
- interpol = log(2 + biasFunction(biasP, Yw / Lmax) * 8);
- L = pade_log(Yw);// log(Yw + 1)
- pixel[x].red = (float)((L / interpol) / divider);
- }
- // next line
- bits += pitch;
- }
- #endif // DRAGO03_FAST
- return TRUE;
- }
- /**
- Custom gamma correction based on the ITU-R BT.709 standard
- @param dib RGBF image to be corrected
- @param gammaval Gamma value (2.2 is a good default value)
- @return Returns TRUE if successful, returns FALSE otherwise
- */
- static BOOL
- REC709GammaCorrection(FIBITMAP *dib, const float gammaval) {
- if(FreeImage_GetImageType(dib) != FIT_RGBF)
- return FALSE;
- float slope = 4.5F;
- float start = 0.018F;
-
- const float fgamma = (float)((0.45 / gammaval) * 2);
- if(gammaval >= 2.1F) {
- start = (float)(0.018 / ((gammaval - 2) * 7.5));
- slope = (float)(4.5 * ((gammaval - 2) * 7.5));
- } else if (gammaval <= 1.9F) {
- start = (float)(0.018 * ((2 - gammaval) * 7.5));
- slope = (float)(4.5 / ((2 - gammaval) * 7.5));
- }
- const unsigned width = FreeImage_GetWidth(dib);
- const unsigned height = FreeImage_GetHeight(dib);
- const unsigned pitch = FreeImage_GetPitch(dib);
- BYTE *bits = (BYTE*)FreeImage_GetBits(dib);
- for(unsigned y = 0; y < height; y++) {
- float *pixel = (float*)bits;
- for(unsigned x = 0; x < width; x++) {
- for(int i = 0; i < 3; i++) {
- *pixel = (*pixel <= start) ? *pixel * slope : (1.099F * pow(*pixel, fgamma) - 0.099F);
- pixel++;
- }
- }
- bits += pitch;
- }
- return TRUE;
- }
- // ----------------------------------------------------------
- // Main algorithm
- // ----------------------------------------------------------
- /**
- Apply the Adaptive Logarithmic Mapping operator to a HDR image and convert to 24-bit RGB
- @param src Input RGB16 or RGB[A]F image
- @param gamma Gamma correction (gamma > 0). 1 means no correction, 2.2 in the original paper.
- @param exposure Exposure parameter (0 means no correction, 0 in the original paper)
- @return Returns a 24-bit RGB image if successful, returns NULL otherwise
- */
- FIBITMAP* DLL_CALLCONV
- FreeImage_TmoDrago03(FIBITMAP *src, double gamma, double exposure) {
- float maxLum, minLum, avgLum;
- if(!FreeImage_HasPixels(src)) return NULL;
- // working RGBF variable
- FIBITMAP *dib = NULL;
- dib = FreeImage_ConvertToRGBF(src);
- if(!dib) return NULL;
- // default algorithm parameters
- const float biasParam = 0.85F;
- const float expoParam = (float)pow(2.0, exposure); //default exposure is 1, 2^0
- // convert to Yxy
- ConvertInPlaceRGBFToYxy(dib);
- // get the luminance
- LuminanceFromYxy(dib, &maxLum, &minLum, &avgLum);
- // perform the tone mapping
- ToneMappingDrago03(dib, maxLum, avgLum, biasParam, expoParam);
- // convert back to RGBF
- ConvertInPlaceYxyToRGBF(dib);
- if(gamma != 1) {
- // perform gamma correction
- REC709GammaCorrection(dib, (float)gamma);
- }
- // clamp image highest values to display white, then convert to 24-bit RGB
- FIBITMAP *dst = ClampConvertRGBFTo24(dib);
- // clean-up and return
- FreeImage_Unload(dib);
- // copy metadata from src to dst
- FreeImage_CloneMetadata(dst, src);
-
- return dst;
- }