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author | Matt A. Tobin <email@mattatobin.com> | 2020-04-07 23:30:51 -0400 |
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committer | Matt A. Tobin <email@mattatobin.com> | 2020-04-07 23:30:51 -0400 |
commit | 5545a8983ff0ef1fb52e64aef8e66fa9b13c1cbb (patch) | |
tree | 45d55e3e5e73c4255c4d71258d9be5b2d004d28f /media/libaom/src/av1/encoder/ransac.c | |
parent | 50f1986697a7412e4160976fa5e11217b4ef1f44 (diff) | |
download | uxp-5545a8983ff0ef1fb52e64aef8e66fa9b13c1cbb.tar.gz |
Move aom source to a sub-directory under media/libaom
There is no damned reason to treat this differently than any other media lib given its license and there never was.
Diffstat (limited to 'media/libaom/src/av1/encoder/ransac.c')
-rw-r--r-- | media/libaom/src/av1/encoder/ransac.c | 603 |
1 files changed, 603 insertions, 0 deletions
diff --git a/media/libaom/src/av1/encoder/ransac.c b/media/libaom/src/av1/encoder/ransac.c new file mode 100644 index 0000000000..781f528ebf --- /dev/null +++ b/media/libaom/src/av1/encoder/ransac.c @@ -0,0 +1,603 @@ +/* + * Copyright (c) 2016, Alliance for Open Media. All rights reserved + * + * This source code is subject to the terms of the BSD 2 Clause License and + * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License + * was not distributed with this source code in the LICENSE file, you can + * obtain it at www.aomedia.org/license/software. If the Alliance for Open + * Media Patent License 1.0 was not distributed with this source code in the + * PATENTS file, you can obtain it at www.aomedia.org/license/patent. + */ +#include <memory.h> +#include <math.h> +#include <time.h> +#include <stdio.h> +#include <stdlib.h> +#include <assert.h> + +#include "av1/encoder/ransac.h" +#include "av1/encoder/mathutils.h" +#include "av1/encoder/random.h" + +#define MAX_MINPTS 4 +#define MAX_DEGENERATE_ITER 10 +#define MINPTS_MULTIPLIER 5 + +#define INLIER_THRESHOLD 1.0 +#define MIN_TRIALS 20 + +//////////////////////////////////////////////////////////////////////////////// +// ransac +typedef int (*IsDegenerateFunc)(double *p); +typedef void (*NormalizeFunc)(double *p, int np, double *T); +typedef void (*DenormalizeFunc)(double *params, double *T1, double *T2); +typedef int (*FindTransformationFunc)(int points, double *points1, + double *points2, double *params); +typedef void (*ProjectPointsDoubleFunc)(double *mat, double *points, + double *proj, const int n, + const int stride_points, + const int stride_proj); + +static void project_points_double_translation(double *mat, double *points, + double *proj, const int n, + const int stride_points, + const int stride_proj) { + int i; + for (i = 0; i < n; ++i) { + const double x = *(points++), y = *(points++); + *(proj++) = x + mat[0]; + *(proj++) = y + mat[1]; + points += stride_points - 2; + proj += stride_proj - 2; + } +} + +static void project_points_double_rotzoom(double *mat, double *points, + double *proj, const int n, + const int stride_points, + const int stride_proj) { + int i; + for (i = 0; i < n; ++i) { + const double x = *(points++), y = *(points++); + *(proj++) = mat[2] * x + mat[3] * y + mat[0]; + *(proj++) = -mat[3] * x + mat[2] * y + mat[1]; + points += stride_points - 2; + proj += stride_proj - 2; + } +} + +static void project_points_double_affine(double *mat, double *points, + double *proj, const int n, + const int stride_points, + const int stride_proj) { + int i; + for (i = 0; i < n; ++i) { + const double x = *(points++), y = *(points++); + *(proj++) = mat[2] * x + mat[3] * y + mat[0]; + *(proj++) = mat[4] * x + mat[5] * y + mat[1]; + points += stride_points - 2; + proj += stride_proj - 2; + } +} + +static void normalize_homography(double *pts, int n, double *T) { + double *p = pts; + double mean[2] = { 0, 0 }; + double msqe = 0; + double scale; + int i; + + assert(n > 0); + for (i = 0; i < n; ++i, p += 2) { + mean[0] += p[0]; + mean[1] += p[1]; + } + mean[0] /= n; + mean[1] /= n; + for (p = pts, i = 0; i < n; ++i, p += 2) { + p[0] -= mean[0]; + p[1] -= mean[1]; + msqe += sqrt(p[0] * p[0] + p[1] * p[1]); + } + msqe /= n; + scale = (msqe == 0 ? 1.0 : sqrt(2) / msqe); + T[0] = scale; + T[1] = 0; + T[2] = -scale * mean[0]; + T[3] = 0; + T[4] = scale; + T[5] = -scale * mean[1]; + T[6] = 0; + T[7] = 0; + T[8] = 1; + for (p = pts, i = 0; i < n; ++i, p += 2) { + p[0] *= scale; + p[1] *= scale; + } +} + +static void invnormalize_mat(double *T, double *iT) { + double is = 1.0 / T[0]; + double m0 = -T[2] * is; + double m1 = -T[5] * is; + iT[0] = is; + iT[1] = 0; + iT[2] = m0; + iT[3] = 0; + iT[4] = is; + iT[5] = m1; + iT[6] = 0; + iT[7] = 0; + iT[8] = 1; +} + +static void denormalize_homography(double *params, double *T1, double *T2) { + double iT2[9]; + double params2[9]; + invnormalize_mat(T2, iT2); + multiply_mat(params, T1, params2, 3, 3, 3); + multiply_mat(iT2, params2, params, 3, 3, 3); +} + +static void denormalize_affine_reorder(double *params, double *T1, double *T2) { + double params_denorm[MAX_PARAMDIM]; + params_denorm[0] = params[0]; + params_denorm[1] = params[1]; + params_denorm[2] = params[4]; + params_denorm[3] = params[2]; + params_denorm[4] = params[3]; + params_denorm[5] = params[5]; + params_denorm[6] = params_denorm[7] = 0; + params_denorm[8] = 1; + denormalize_homography(params_denorm, T1, T2); + params[0] = params_denorm[2]; + params[1] = params_denorm[5]; + params[2] = params_denorm[0]; + params[3] = params_denorm[1]; + params[4] = params_denorm[3]; + params[5] = params_denorm[4]; + params[6] = params[7] = 0; +} + +static void denormalize_rotzoom_reorder(double *params, double *T1, + double *T2) { + double params_denorm[MAX_PARAMDIM]; + params_denorm[0] = params[0]; + params_denorm[1] = params[1]; + params_denorm[2] = params[2]; + params_denorm[3] = -params[1]; + params_denorm[4] = params[0]; + params_denorm[5] = params[3]; + params_denorm[6] = params_denorm[7] = 0; + params_denorm[8] = 1; + denormalize_homography(params_denorm, T1, T2); + params[0] = params_denorm[2]; + params[1] = params_denorm[5]; + params[2] = params_denorm[0]; + params[3] = params_denorm[1]; + params[4] = -params[3]; + params[5] = params[2]; + params[6] = params[7] = 0; +} + +static void denormalize_translation_reorder(double *params, double *T1, + double *T2) { + double params_denorm[MAX_PARAMDIM]; + params_denorm[0] = 1; + params_denorm[1] = 0; + params_denorm[2] = params[0]; + params_denorm[3] = 0; + params_denorm[4] = 1; + params_denorm[5] = params[1]; + params_denorm[6] = params_denorm[7] = 0; + params_denorm[8] = 1; + denormalize_homography(params_denorm, T1, T2); + params[0] = params_denorm[2]; + params[1] = params_denorm[5]; + params[2] = params[5] = 1; + params[3] = params[4] = 0; + params[6] = params[7] = 0; +} + +static int find_translation(int np, double *pts1, double *pts2, double *mat) { + int i; + double sx, sy, dx, dy; + double sumx, sumy; + + double T1[9], T2[9]; + normalize_homography(pts1, np, T1); + normalize_homography(pts2, np, T2); + + sumx = 0; + sumy = 0; + for (i = 0; i < np; ++i) { + dx = *(pts2++); + dy = *(pts2++); + sx = *(pts1++); + sy = *(pts1++); + + sumx += dx - sx; + sumy += dy - sy; + } + mat[0] = sumx / np; + mat[1] = sumy / np; + denormalize_translation_reorder(mat, T1, T2); + return 0; +} + +static int find_rotzoom(int np, double *pts1, double *pts2, double *mat) { + const int np2 = np * 2; + double *a = (double *)aom_malloc(sizeof(*a) * (np2 * 5 + 20)); + double *b = a + np2 * 4; + double *temp = b + np2; + int i; + double sx, sy, dx, dy; + + double T1[9], T2[9]; + normalize_homography(pts1, np, T1); + normalize_homography(pts2, np, T2); + + for (i = 0; i < np; ++i) { + dx = *(pts2++); + dy = *(pts2++); + sx = *(pts1++); + sy = *(pts1++); + + a[i * 2 * 4 + 0] = sx; + a[i * 2 * 4 + 1] = sy; + a[i * 2 * 4 + 2] = 1; + a[i * 2 * 4 + 3] = 0; + a[(i * 2 + 1) * 4 + 0] = sy; + a[(i * 2 + 1) * 4 + 1] = -sx; + a[(i * 2 + 1) * 4 + 2] = 0; + a[(i * 2 + 1) * 4 + 3] = 1; + + b[2 * i] = dx; + b[2 * i + 1] = dy; + } + if (!least_squares(4, a, np2, 4, b, temp, mat)) { + aom_free(a); + return 1; + } + denormalize_rotzoom_reorder(mat, T1, T2); + aom_free(a); + return 0; +} + +static int find_affine(int np, double *pts1, double *pts2, double *mat) { + const int np2 = np * 2; + double *a = (double *)aom_malloc(sizeof(*a) * (np2 * 7 + 42)); + double *b = a + np2 * 6; + double *temp = b + np2; + int i; + double sx, sy, dx, dy; + + double T1[9], T2[9]; + normalize_homography(pts1, np, T1); + normalize_homography(pts2, np, T2); + + for (i = 0; i < np; ++i) { + dx = *(pts2++); + dy = *(pts2++); + sx = *(pts1++); + sy = *(pts1++); + + a[i * 2 * 6 + 0] = sx; + a[i * 2 * 6 + 1] = sy; + a[i * 2 * 6 + 2] = 0; + a[i * 2 * 6 + 3] = 0; + a[i * 2 * 6 + 4] = 1; + a[i * 2 * 6 + 5] = 0; + a[(i * 2 + 1) * 6 + 0] = 0; + a[(i * 2 + 1) * 6 + 1] = 0; + a[(i * 2 + 1) * 6 + 2] = sx; + a[(i * 2 + 1) * 6 + 3] = sy; + a[(i * 2 + 1) * 6 + 4] = 0; + a[(i * 2 + 1) * 6 + 5] = 1; + + b[2 * i] = dx; + b[2 * i + 1] = dy; + } + if (!least_squares(6, a, np2, 6, b, temp, mat)) { + aom_free(a); + return 1; + } + denormalize_affine_reorder(mat, T1, T2); + aom_free(a); + return 0; +} + +static int get_rand_indices(int npoints, int minpts, int *indices, + unsigned int *seed) { + int i, j; + int ptr = lcg_rand16(seed) % npoints; + if (minpts > npoints) return 0; + indices[0] = ptr; + ptr = (ptr == npoints - 1 ? 0 : ptr + 1); + i = 1; + while (i < minpts) { + int index = lcg_rand16(seed) % npoints; + while (index) { + ptr = (ptr == npoints - 1 ? 0 : ptr + 1); + for (j = 0; j < i; ++j) { + if (indices[j] == ptr) break; + } + if (j == i) index--; + } + indices[i++] = ptr; + } + return 1; +} + +typedef struct { + int num_inliers; + double variance; + int *inlier_indices; +} RANSAC_MOTION; + +// Return -1 if 'a' is a better motion, 1 if 'b' is better, 0 otherwise. +static int compare_motions(const void *arg_a, const void *arg_b) { + const RANSAC_MOTION *motion_a = (RANSAC_MOTION *)arg_a; + const RANSAC_MOTION *motion_b = (RANSAC_MOTION *)arg_b; + + if (motion_a->num_inliers > motion_b->num_inliers) return -1; + if (motion_a->num_inliers < motion_b->num_inliers) return 1; + if (motion_a->variance < motion_b->variance) return -1; + if (motion_a->variance > motion_b->variance) return 1; + return 0; +} + +static int is_better_motion(const RANSAC_MOTION *motion_a, + const RANSAC_MOTION *motion_b) { + return compare_motions(motion_a, motion_b) < 0; +} + +static void copy_points_at_indices(double *dest, const double *src, + const int *indices, int num_points) { + for (int i = 0; i < num_points; ++i) { + const int index = indices[i]; + dest[i * 2] = src[index * 2]; + dest[i * 2 + 1] = src[index * 2 + 1]; + } +} + +static const double kInfiniteVariance = 1e12; + +static void clear_motion(RANSAC_MOTION *motion, int num_points) { + motion->num_inliers = 0; + motion->variance = kInfiniteVariance; + memset(motion->inlier_indices, 0, + sizeof(*motion->inlier_indices * num_points)); +} + +static int ransac(const int *matched_points, int npoints, + int *num_inliers_by_motion, double *params_by_motion, + int num_desired_motions, const int minpts, + IsDegenerateFunc is_degenerate, + FindTransformationFunc find_transformation, + ProjectPointsDoubleFunc projectpoints) { + static const double PROBABILITY_REQUIRED = 0.9; + static const double EPS = 1e-12; + + int N = 10000, trial_count = 0; + int i = 0; + int ret_val = 0; + + unsigned int seed = (unsigned int)npoints; + + int indices[MAX_MINPTS] = { 0 }; + + double *points1, *points2; + double *corners1, *corners2; + double *image1_coord; + + // Store information for the num_desired_motions best transformations found + // and the worst motion among them, as well as the motion currently under + // consideration. + RANSAC_MOTION *motions, *worst_kept_motion = NULL; + RANSAC_MOTION current_motion; + + // Store the parameters and the indices of the inlier points for the motion + // currently under consideration. + double params_this_motion[MAX_PARAMDIM]; + + double *cnp1, *cnp2; + + for (i = 0; i < num_desired_motions; ++i) { + num_inliers_by_motion[i] = 0; + } + if (npoints < minpts * MINPTS_MULTIPLIER || npoints == 0) { + return 1; + } + + points1 = (double *)aom_malloc(sizeof(*points1) * npoints * 2); + points2 = (double *)aom_malloc(sizeof(*points2) * npoints * 2); + corners1 = (double *)aom_malloc(sizeof(*corners1) * npoints * 2); + corners2 = (double *)aom_malloc(sizeof(*corners2) * npoints * 2); + image1_coord = (double *)aom_malloc(sizeof(*image1_coord) * npoints * 2); + + motions = + (RANSAC_MOTION *)aom_malloc(sizeof(RANSAC_MOTION) * num_desired_motions); + for (i = 0; i < num_desired_motions; ++i) { + motions[i].inlier_indices = + (int *)aom_malloc(sizeof(*motions->inlier_indices) * npoints); + clear_motion(motions + i, npoints); + } + current_motion.inlier_indices = + (int *)aom_malloc(sizeof(*current_motion.inlier_indices) * npoints); + clear_motion(¤t_motion, npoints); + + worst_kept_motion = motions; + + if (!(points1 && points2 && corners1 && corners2 && image1_coord && motions && + current_motion.inlier_indices)) { + ret_val = 1; + goto finish_ransac; + } + + cnp1 = corners1; + cnp2 = corners2; + for (i = 0; i < npoints; ++i) { + *(cnp1++) = *(matched_points++); + *(cnp1++) = *(matched_points++); + *(cnp2++) = *(matched_points++); + *(cnp2++) = *(matched_points++); + } + + while (N > trial_count) { + double sum_distance = 0.0; + double sum_distance_squared = 0.0; + + clear_motion(¤t_motion, npoints); + + int degenerate = 1; + int num_degenerate_iter = 0; + + while (degenerate) { + num_degenerate_iter++; + if (!get_rand_indices(npoints, minpts, indices, &seed)) { + ret_val = 1; + goto finish_ransac; + } + + copy_points_at_indices(points1, corners1, indices, minpts); + copy_points_at_indices(points2, corners2, indices, minpts); + + degenerate = is_degenerate(points1); + if (num_degenerate_iter > MAX_DEGENERATE_ITER) { + ret_val = 1; + goto finish_ransac; + } + } + + if (find_transformation(minpts, points1, points2, params_this_motion)) { + trial_count++; + continue; + } + + projectpoints(params_this_motion, corners1, image1_coord, npoints, 2, 2); + + for (i = 0; i < npoints; ++i) { + double dx = image1_coord[i * 2] - corners2[i * 2]; + double dy = image1_coord[i * 2 + 1] - corners2[i * 2 + 1]; + double distance = sqrt(dx * dx + dy * dy); + + if (distance < INLIER_THRESHOLD) { + current_motion.inlier_indices[current_motion.num_inliers++] = i; + sum_distance += distance; + sum_distance_squared += distance * distance; + } + } + + if (current_motion.num_inliers >= worst_kept_motion->num_inliers && + current_motion.num_inliers > 1) { + int temp; + double fracinliers, pNoOutliers, mean_distance, dtemp; + mean_distance = sum_distance / ((double)current_motion.num_inliers); + current_motion.variance = + sum_distance_squared / ((double)current_motion.num_inliers - 1.0) - + mean_distance * mean_distance * ((double)current_motion.num_inliers) / + ((double)current_motion.num_inliers - 1.0); + if (is_better_motion(¤t_motion, worst_kept_motion)) { + // This motion is better than the worst currently kept motion. Remember + // the inlier points and variance. The parameters for each kept motion + // will be recomputed later using only the inliers. + worst_kept_motion->num_inliers = current_motion.num_inliers; + worst_kept_motion->variance = current_motion.variance; + memcpy(worst_kept_motion->inlier_indices, current_motion.inlier_indices, + sizeof(*current_motion.inlier_indices) * npoints); + + assert(npoints > 0); + fracinliers = (double)current_motion.num_inliers / (double)npoints; + pNoOutliers = 1 - pow(fracinliers, minpts); + pNoOutliers = fmax(EPS, pNoOutliers); + pNoOutliers = fmin(1 - EPS, pNoOutliers); + dtemp = log(1.0 - PROBABILITY_REQUIRED) / log(pNoOutliers); + temp = (dtemp > (double)INT32_MAX) + ? INT32_MAX + : dtemp < (double)INT32_MIN ? INT32_MIN : (int)dtemp; + + if (temp > 0 && temp < N) { + N = AOMMAX(temp, MIN_TRIALS); + } + + // Determine the new worst kept motion and its num_inliers and variance. + for (i = 0; i < num_desired_motions; ++i) { + if (is_better_motion(worst_kept_motion, &motions[i])) { + worst_kept_motion = &motions[i]; + } + } + } + } + trial_count++; + } + + // Sort the motions, best first. + qsort(motions, num_desired_motions, sizeof(RANSAC_MOTION), compare_motions); + + // Recompute the motions using only the inliers. + for (i = 0; i < num_desired_motions; ++i) { + if (motions[i].num_inliers >= minpts) { + copy_points_at_indices(points1, corners1, motions[i].inlier_indices, + motions[i].num_inliers); + copy_points_at_indices(points2, corners2, motions[i].inlier_indices, + motions[i].num_inliers); + + find_transformation(motions[i].num_inliers, points1, points2, + params_by_motion + (MAX_PARAMDIM - 1) * i); + } + num_inliers_by_motion[i] = motions[i].num_inliers; + } + +finish_ransac: + aom_free(points1); + aom_free(points2); + aom_free(corners1); + aom_free(corners2); + aom_free(image1_coord); + aom_free(current_motion.inlier_indices); + for (i = 0; i < num_desired_motions; ++i) { + aom_free(motions[i].inlier_indices); + } + aom_free(motions); + + return ret_val; +} + +static int is_collinear3(double *p1, double *p2, double *p3) { + static const double collinear_eps = 1e-3; + const double v = + (p2[0] - p1[0]) * (p3[1] - p1[1]) - (p2[1] - p1[1]) * (p3[0] - p1[0]); + return fabs(v) < collinear_eps; +} + +static int is_degenerate_translation(double *p) { + return (p[0] - p[2]) * (p[0] - p[2]) + (p[1] - p[3]) * (p[1] - p[3]) <= 2; +} + +static int is_degenerate_affine(double *p) { + return is_collinear3(p, p + 2, p + 4); +} + +int ransac_translation(int *matched_points, int npoints, + int *num_inliers_by_motion, double *params_by_motion, + int num_desired_motions) { + return ransac(matched_points, npoints, num_inliers_by_motion, + params_by_motion, num_desired_motions, 3, + is_degenerate_translation, find_translation, + project_points_double_translation); +} + +int ransac_rotzoom(int *matched_points, int npoints, int *num_inliers_by_motion, + double *params_by_motion, int num_desired_motions) { + return ransac(matched_points, npoints, num_inliers_by_motion, + params_by_motion, num_desired_motions, 3, is_degenerate_affine, + find_rotzoom, project_points_double_rotzoom); +} + +int ransac_affine(int *matched_points, int npoints, int *num_inliers_by_motion, + double *params_by_motion, int num_desired_motions) { + return ransac(matched_points, npoints, num_inliers_by_motion, + params_by_motion, num_desired_motions, 3, is_degenerate_affine, + find_affine, project_points_double_affine); +} |