2 * Copyright (c) 2018 Mina Sami
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * Color Constancy filter
25 * @see http://colorconstancy.com/
28 * J. van de Weijer, Th. Gevers, A. Gijsenij "Edge-Based Color Constancy".
31 #include "libavutil/imgutils.h"
32 #include "libavutil/opt.h"
33 #include "libavutil/pixdesc.h"
42 #define GREY_EDGE "greyedge"
44 #define SQRT3 1.73205080757
47 #define MAX_DIFF_ORD 2
48 #define MAX_META_DATA 4
55 #define INDEX_NORM INDEX_DX
64 * Used for passing data between threads.
66 typedef struct ThreadData {
68 int meta_data[MAX_META_DATA];
69 double *data[MAX_DATA][NUM_PLANES];
73 * Common struct for all algorithms contexts.
75 typedef struct ColorConstancyContext {
79 int minknorm; /**< @minknorm = 0 : getMax instead */
87 double *gauss[MAX_DIFF_ORD+1];
89 double white[NUM_PLANES];
90 } ColorConstancyContext;
92 #define OFFSET(x) offsetof(ColorConstancyContext, x)
93 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
95 #define GINDX(s, i) ( (i) - ((s) >> 2) )
98 * Sets gauss filters used for calculating gauss derivatives. Filter size
99 * depends on sigma which is a user option hence we calculate these
100 * filters each time. Also each higher order depends on lower ones. Sigma
101 * can be zero only at difford = 0, then we only convert data to double
104 * @param ctx the filter context.
106 * @return 0 in case of success, a negative value corresponding to an
107 * AVERROR code in case of failure.
109 static int set_gauss(AVFilterContext *ctx)
111 ColorConstancyContext *s = ctx->priv;
112 int filtersize = s->filtersize;
113 int difford = s->difford;
114 double sigma = s->sigma;
118 for (i = 0; i <= difford; ++i) {
119 s->gauss[i] = av_mallocz_array(filtersize, sizeof(*s->gauss[i]));
121 for (; i >= 0; --i) {
122 av_freep(&s->gauss[i]);
124 return AVERROR(ENOMEM);
129 av_log(ctx, AV_LOG_TRACE, "Setting 0-d gauss with filtersize = %d.\n", filtersize);
132 s->gauss[0][0] = 1; // Copying data to double instead of convolution
134 for (i = 0; i < filtersize; ++i) {
135 s->gauss[0][i] = exp(- pow(GINDX(filtersize, i), 2.) / (2 * sigma * sigma)) / ( sqrt(2 * M_PI) * sigma );
136 sum1 += s->gauss[0][i];
138 for (i = 0; i < filtersize; ++i) {
139 s->gauss[0][i] /= sum1;
144 av_log(ctx, AV_LOG_TRACE, "Setting 1-d gauss with filtersize = %d.\n", filtersize);
146 for (i = 0; i < filtersize; ++i) {
147 s->gauss[1][i] = - (GINDX(filtersize, i) / pow(sigma, 2)) * s->gauss[0][i];
148 sum1 += s->gauss[1][i] * GINDX(filtersize, i);
151 for (i = 0; i < filtersize; ++i) {
152 s->gauss[1][i] /= sum1;
157 av_log(ctx, AV_LOG_TRACE, "Setting 2-d gauss with filtersize = %d.\n", filtersize);
159 for (i = 0; i < filtersize; ++i) {
160 s->gauss[2][i] = ( pow(GINDX(filtersize, i), 2) / pow(sigma, 4) - 1/pow(sigma, 2) )
162 sum1 += s->gauss[2][i];
166 for (i = 0; i < filtersize; ++i) {
167 s->gauss[2][i] -= sum1 / (filtersize);
168 sum2 += (0.5 * GINDX(filtersize, i) * GINDX(filtersize, i) * s->gauss[2][i]);
170 for (i = 0; i < filtersize ; ++i) {
171 s->gauss[2][i] /= sum2;
179 * Frees up buffers used by grey edge for storing derivatives final
180 * and intermidiate results. Number of buffers and number of planes
181 * for last buffer are given so it can be safely called at allocation
184 * @param td holds the buffers.
185 * @param nb_buff number of buffers to be freed.
186 * @param nb_planes number of planes for last buffer to be freed.
188 static void cleanup_derivative_buffers(ThreadData *td, int nb_buff, int nb_planes)
192 for (b = 0; b < nb_buff; ++b) {
193 for (p = 0; p < NUM_PLANES; ++p) {
194 av_freep(&td->data[b][p]);
197 // Final buffer may not be fully allocated at fail cases
198 for (p = 0; p < nb_planes; ++p) {
199 av_freep(&td->data[b][p]);
204 * Allocates buffers used by grey edge for storing derivatives final
205 * and intermidiate results.
207 * @param ctx the filter context.
208 * @param td holds the buffers.
210 * @return 0 in case of success, a negative value corresponding to an
211 * AVERROR code in case of failure.
213 static int setup_derivative_buffers(AVFilterContext* ctx, ThreadData *td)
215 ColorConstancyContext *s = ctx->priv;
216 int nb_buff = s->difford + 1;
219 av_log(ctx, AV_LOG_TRACE, "Allocating %d buffer(s) for grey edge.\n", nb_buff);
220 for (b = 0; b <= nb_buff; ++b) { // We need difford + 1 buffers
221 for (p = 0; p < NUM_PLANES; ++p) {
222 td->data[b][p] = av_mallocz_array(s->planeheight[p] * s->planewidth[p], sizeof(*td->data[b][p]));
223 if (!td->data[b][p]) {
224 cleanup_derivative_buffers(td, b + 1, p);
225 return AVERROR(ENOMEM);
232 #define CLAMP(x, mx) av_clip((x), 0, (mx-1))
233 #define INDX2D(r, c, w) ( (r) * (w) + (c) )
234 #define GAUSS(s, sr, sc, sls, sh, sw, g) ( (s)[ INDX2D(CLAMP((sr), (sh)), CLAMP((sc), (sw)), (sls)) ] * (g) )
237 * Slice calculation of gaussian derivatives. Applies 1-D gaussian derivative filter
238 * either horizontally or vertically according to meta data given in thread data.
239 * When convoluting horizontally source is always the in frame withing thread data
240 * while when convoluting vertically source is a buffer.
242 * @param ctx the filter context.
243 * @param arg data to be passed between threads.
244 * @param jobnr current job nubmer.
245 * @param nb_jobs total number of jobs.
249 static int slice_get_derivative(AVFilterContext* ctx, void* arg, int jobnr, int nb_jobs)
251 ColorConstancyContext *s = ctx->priv;
252 ThreadData *td = arg;
253 AVFrame *in = td->in;
254 const int ord = td->meta_data[INDEX_ORD];
255 const int dir = td->meta_data[INDEX_DIR];
256 const int src_index = td->meta_data[INDEX_SRC];
257 const int dst_index = td->meta_data[INDEX_DST];
258 const int filtersize = s->filtersize;
259 const double *gauss = s->gauss[ord];
262 for (plane = 0; plane < NUM_PLANES; ++plane) {
263 const int height = s->planeheight[plane];
264 const int width = s->planewidth[plane];
265 const int in_linesize = in->linesize[plane];
266 double *dst = td->data[dst_index][plane];
267 int slice_start, slice_end;
271 /** Applying gauss horizontally along each row */
272 const uint8_t *src = in->data[plane];
273 slice_start = (height * jobnr ) / nb_jobs;
274 slice_end = (height * (jobnr + 1)) / nb_jobs;
276 for (r = slice_start; r < slice_end; ++r) {
277 for (c = 0; c < width; ++c) {
278 dst[INDX2D(r, c, width)] = 0;
279 for (g = 0; g < filtersize; ++g) {
280 dst[INDX2D(r, c, width)] += GAUSS(src, r, c + GINDX(filtersize, g),
281 in_linesize, height, width, gauss[g]);
286 /** Applying gauss vertically along each column */
287 const double *src = td->data[src_index][plane];
288 slice_start = (width * jobnr ) / nb_jobs;
289 slice_end = (width * (jobnr + 1)) / nb_jobs;
291 for (c = slice_start; c < slice_end; ++c) {
292 for (r = 0; r < height; ++r) {
293 dst[INDX2D(r, c, width)] = 0;
294 for (g = 0; g < filtersize; ++g) {
295 dst[INDX2D(r, c, width)] += GAUSS(src, r + GINDX(filtersize, g), c,
296 width, height, width, gauss[g]);
307 * Slice Frobius normalization of gaussian derivatives. Only called for difford values of
310 * @param ctx the filter context.
311 * @param arg data to be passed between threads.
312 * @param jobnr current job nubmer.
313 * @param nb_jobs total number of jobs.
317 static int slice_normalize(AVFilterContext* ctx, void* arg, int jobnr, int nb_jobs)
319 ColorConstancyContext *s = ctx->priv;
320 ThreadData *td = arg;
321 const int difford = s->difford;
324 for (plane = 0; plane < NUM_PLANES; ++plane) {
325 const int height = s->planeheight[plane];
326 const int width = s->planewidth[plane];
327 const int64_t numpixels = width * (int64_t)height;
328 const int slice_start = (numpixels * jobnr ) / nb_jobs;
329 const int slice_end = (numpixels * (jobnr+1)) / nb_jobs;
330 const double *dx = td->data[INDEX_DX][plane];
331 const double *dy = td->data[INDEX_DY][plane];
332 double *norm = td->data[INDEX_NORM][plane];
336 for (i = slice_start; i < slice_end; ++i) {
337 norm[i] = sqrt( pow(dx[i], 2) + pow(dy[i], 2));
340 const double *dxy = td->data[INDEX_DXY][plane];
341 for (i = slice_start; i < slice_end; ++i) {
342 norm[i] = sqrt( pow(dx[i], 2) + 4 * pow(dxy[i], 2) + pow(dy[i], 2) );
351 * Utility function for setting up differentiation data/metadata.
353 * @param ctx the filter context.
354 * @param td to be used for passing data between threads.
355 * @param ord ord of differentiation.
356 * @param dir direction of differentiation.
357 * @param src index of source used for differentiation.
358 * @param dst index destination used for saving differentiation result.
359 * @param dim maximum dimension in current direction.
360 * @param nb_threads number of threads to use.
362 static void av_always_inline
363 get_deriv(AVFilterContext *ctx, ThreadData *td, int ord, int dir,
364 int src, int dst, int dim, int nb_threads) {
365 td->meta_data[INDEX_ORD] = ord;
366 td->meta_data[INDEX_DIR] = dir;
367 td->meta_data[INDEX_SRC] = src;
368 td->meta_data[INDEX_DST] = dst;
369 ctx->internal->execute(ctx, slice_get_derivative, td, NULL, FFMIN(dim, nb_threads));
373 * Main control function for calculating gaussian derivatives.
375 * @param ctx the filter context.
376 * @param td holds the buffers used for storing results.
378 * @return 0 in case of success, a negative value corresponding to an
379 * AVERROR code in case of failure.
381 static int get_derivative(AVFilterContext *ctx, ThreadData *td)
383 ColorConstancyContext *s = ctx->priv;
384 int nb_threads = s->nb_threads;
385 int height = s->planeheight[1];
386 int width = s->planewidth[1];
390 if (!s->sigma) { // Only copy once
391 get_deriv(ctx, td, 0, DIR_X, 0 , INDEX_NORM, height, nb_threads);
393 get_deriv(ctx, td, 0, DIR_X, 0, INDEX_TEMP, height, nb_threads);
394 get_deriv(ctx, td, 0, DIR_Y, INDEX_TEMP, INDEX_NORM, width , nb_threads);
395 // save to INDEX_NORM because this will not be normalied and
396 // end gry edge filter expects result to be found in INDEX_NORM
401 get_deriv(ctx, td, 1, DIR_X, 0, INDEX_TEMP, height, nb_threads);
402 get_deriv(ctx, td, 0, DIR_Y, INDEX_TEMP, INDEX_DX, width , nb_threads);
404 get_deriv(ctx, td, 0, DIR_X, 0, INDEX_TEMP, height, nb_threads);
405 get_deriv(ctx, td, 1, DIR_Y, INDEX_TEMP, INDEX_DY, width , nb_threads);
409 get_deriv(ctx, td, 2, DIR_X, 0, INDEX_TEMP, height, nb_threads);
410 get_deriv(ctx, td, 0, DIR_Y, INDEX_TEMP, INDEX_DX, width , nb_threads);
412 get_deriv(ctx, td, 0, DIR_X, 0, INDEX_TEMP, height, nb_threads);
413 get_deriv(ctx, td, 2, DIR_Y, INDEX_TEMP, INDEX_DY, width , nb_threads);
415 get_deriv(ctx, td, 1, DIR_X, 0, INDEX_TEMP, height, nb_threads);
416 get_deriv(ctx, td, 1, DIR_Y, INDEX_TEMP, INDEX_DXY, width , nb_threads);
420 av_log(ctx, AV_LOG_ERROR, "Unsupported difford value: %d.\n", s->difford);
421 return AVERROR(EINVAL);
427 * Slice function for grey edge algorithm that does partial summing/maximizing
428 * of gaussian derivatives.
430 * @param ctx the filter context.
431 * @param arg data to be passed between threads.
432 * @param jobnr current job nubmer.
433 * @param nb_jobs total number of jobs.
437 static int filter_slice_grey_edge(AVFilterContext* ctx, void* arg, int jobnr, int nb_jobs)
439 ColorConstancyContext *s = ctx->priv;
440 ThreadData *td = arg;
441 AVFrame *in = td->in;
442 int minknorm = s->minknorm;
443 const uint8_t thresh = 255;
446 for (plane = 0; plane < NUM_PLANES; ++plane) {
447 const int height = s->planeheight[plane];
448 const int width = s->planewidth[plane];
449 const int in_linesize = in->linesize[plane];
450 const int slice_start = (height * jobnr) / nb_jobs;
451 const int slice_end = (height * (jobnr+1)) / nb_jobs;
452 const uint8_t *img_data = in->data[plane];
453 const double *src = td->data[INDEX_NORM][plane];
454 double *dst = td->data[INDEX_DST][plane];
459 for (r = slice_start; r < slice_end; ++r) {
460 for (c = 0; c < width; ++c) {
461 dst[jobnr] = FFMAX( dst[jobnr], fabs(src[INDX2D(r, c, width)])
462 * (img_data[INDX2D(r, c, in_linesize)] < thresh) );
466 for (r = slice_start; r < slice_end; ++r) {
467 for (c = 0; c < width; ++c) {
468 dst[jobnr] += ( pow( fabs(src[INDX2D(r, c, width)] / 255.), minknorm)
469 * (img_data[INDX2D(r, c, in_linesize)] < thresh) );
478 * Main control function for grey edge algorithm.
480 * @param ctx the filter context.
481 * @param in frame to perfrom grey edge on.
483 * @return 0 in case of success, a negative value corresponding to an
484 * AVERROR code in case of failure.
486 static int filter_grey_edge(AVFilterContext *ctx, AVFrame *in)
488 ColorConstancyContext *s = ctx->priv;
490 int minknorm = s->minknorm;
491 int difford = s->difford;
492 double *white = s->white;
493 int nb_jobs = FFMIN3(s->planeheight[1], s->planewidth[1], s->nb_threads);
497 ret = setup_derivative_buffers(ctx, &td);
501 get_derivative(ctx, &td);
503 ctx->internal->execute(ctx, slice_normalize, &td, NULL, nb_jobs);
506 ctx->internal->execute(ctx, filter_slice_grey_edge, &td, NULL, nb_jobs);
508 for (plane = 0; plane < NUM_PLANES; ++plane) {
509 white[plane] = 0; // All values are absolute
510 for (job = 0; job < nb_jobs; ++job) {
511 white[plane] = FFMAX(white[plane] , td.data[INDEX_DST][plane][job]);
515 for (plane = 0; plane < NUM_PLANES; ++plane) {
517 for (job = 0; job < nb_jobs; ++job) {
518 white[plane] += td.data[INDEX_DST][plane][job];
520 white[plane] = pow(white[plane], 1./minknorm);
524 cleanup_derivative_buffers(&td, difford + 1, NUM_PLANES);
529 * Normalizes estimated illumination since only illumination vector
530 * direction is required for color constancy.
532 * @param light the estimated illumination to be normalized in place
534 static void normalize_light(double *light)
536 double abs_val = pow( pow(light[0], 2.0) + pow(light[1], 2.0) + pow(light[2], 2.0), 0.5);
539 // TODO: check if setting to 1.0 when estimated = 0.0 is the best thing to do
542 for (plane = 0; plane < NUM_PLANES; ++plane) {
546 for (plane = 0; plane < NUM_PLANES; ++plane) {
547 light[plane] = (light[plane] / abs_val);
548 if (!light[plane]) { // to avoid division by zero when correcting
556 * Redirects to corresponding algorithm estimation function and performs normalization
559 * @param ctx the filter context.
560 * @param in frame to perfrom estimation on.
562 * @return 0 in case of success, a negative value corresponding to an
563 * AVERROR code in case of failure.
565 static int illumination_estimation(AVFilterContext *ctx, AVFrame *in)
567 ColorConstancyContext *s = ctx->priv;
570 ret = filter_grey_edge(ctx, in);
572 av_log(ctx, AV_LOG_DEBUG, "Estimated illumination= %f %f %f\n",
573 s->white[0], s->white[1], s->white[2]);
574 normalize_light(s->white);
575 av_log(ctx, AV_LOG_DEBUG, "Estimated illumination after normalization= %f %f %f\n",
576 s->white[0], s->white[1], s->white[2]);
582 * Performs simple correction via diagonal transformation model.
584 * @param ctx the filter context.
585 * @param arg data to be passed between threads.
586 * @param jobnr current job nubmer.
587 * @param nb_jobs total number of jobs.
591 static int diagonal_transformation(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
593 ColorConstancyContext *s = ctx->priv;
594 ThreadData *td = arg;
595 AVFrame *in = td->in;
596 AVFrame *out = td->out;
599 for (plane = 0; plane < NUM_PLANES; ++plane) {
600 const int height = s->planeheight[plane];
601 const int width = s->planewidth[plane];
602 const int64_t numpixels = width * (int64_t)height;
603 const int slice_start = (numpixels * jobnr) / nb_jobs;
604 const int slice_end = (numpixels * (jobnr+1)) / nb_jobs;
605 const uint8_t *src = in->data[plane];
606 uint8_t *dst = out->data[plane];
610 for (i = slice_start; i < slice_end; ++i) {
611 temp = src[i] / (s->white[plane] * SQRT3);
612 dst[i] = av_clip_uint8((int)(temp + 0.5));
619 * Main control function for correcting scene illumination based on
620 * estimated illumination.
622 * @param ctx the filter context.
623 * @param in holds frame to correct
624 * @param out holds corrected frame
626 static void chromatic_adaptation(AVFilterContext *ctx, AVFrame *in, AVFrame *out)
628 ColorConstancyContext *s = ctx->priv;
630 int nb_jobs = FFMIN3(s->planeheight[1], s->planewidth[1], s->nb_threads);
634 ctx->internal->execute(ctx, diagonal_transformation, &td, NULL, nb_jobs);
637 static int query_formats(AVFilterContext *ctx)
639 static const enum AVPixelFormat pix_fmts[] = {
640 // TODO: support more formats
641 // FIXME: error when saving to .jpg
646 return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
649 static int config_props(AVFilterLink *inlink)
651 AVFilterContext *ctx = inlink->dst;
652 ColorConstancyContext *s = ctx->priv;
653 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
654 const double break_off_sigma = 3.0;
655 double sigma = s->sigma;
658 if (!floor(break_off_sigma * sigma + 0.5) && s->difford) {
659 av_log(ctx, AV_LOG_ERROR, "floor(%f * sigma) must be > 0 when difford > 0.\n", break_off_sigma);
660 return AVERROR(EINVAL);
663 s->filtersize = 2 * floor(break_off_sigma * sigma + 0.5) + 1;
664 if (ret=set_gauss(ctx)) {
668 s->nb_threads = ff_filter_get_nb_threads(ctx);
669 s->planewidth[1] = s->planewidth[2] = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
670 s->planewidth[0] = s->planewidth[3] = inlink->w;
671 s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
672 s->planeheight[0] = s->planeheight[3] = inlink->h;
677 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
679 AVFilterContext *ctx = inlink->dst;
680 AVFilterLink *outlink = ctx->outputs[0];
685 ret = illumination_estimation(ctx, in);
691 if (av_frame_is_writable(in)) {
695 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
698 return AVERROR(ENOMEM);
700 av_frame_copy_props(out, in);
702 chromatic_adaptation(ctx, in, out);
707 return ff_filter_frame(outlink, out);
710 static av_cold void uninit(AVFilterContext *ctx)
712 ColorConstancyContext *s = ctx->priv;
713 int difford = s->difford;
716 for (i = 0; i <= difford; ++i) {
717 av_freep(&s->gauss[i]);
721 static const AVFilterPad colorconstancy_inputs[] = {
724 .type = AVMEDIA_TYPE_VIDEO,
725 .config_props = config_props,
726 .filter_frame = filter_frame,
731 static const AVFilterPad colorconstancy_outputs[] = {
734 .type = AVMEDIA_TYPE_VIDEO,
739 #if CONFIG_GREYEDGE_FILTER
741 static const AVOption greyedge_options[] = {
742 { "difford", "set differentiation order", OFFSET(difford), AV_OPT_TYPE_INT, {.i64=1}, 0, 2, FLAGS },
743 { "minknorm", "set Minkowski norm", OFFSET(minknorm), AV_OPT_TYPE_INT, {.i64=1}, 0, 20, FLAGS },
744 { "sigma", "set sigma", OFFSET(sigma), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.0, 1024.0, FLAGS },
748 AVFILTER_DEFINE_CLASS(greyedge);
750 AVFilter ff_vf_greyedge = {
752 .description = NULL_IF_CONFIG_SMALL("Estimates scene illumination by grey edge assumption."),
753 .priv_size = sizeof(ColorConstancyContext),
754 .priv_class = &greyedge_class,
755 .query_formats = query_formats,
757 .inputs = colorconstancy_inputs,
758 .outputs = colorconstancy_outputs,
759 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
762 #endif /* CONFIG_GREY_EDGE_FILTER */