91 lines
3.2 KiB
C
91 lines
3.2 KiB
C
/*
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* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <memory.h>
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#include <math.h>
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#include <assert.h>
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#include "av1/common/warped_motion.h"
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#include "av1/encoder/segmentation.h"
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#include "av1/encoder/global_motion.h"
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#include "av1/encoder/corner_detect.h"
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#include "av1/encoder/corner_match.h"
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#include "av1/encoder/ransac.h"
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#define MAX_CORNERS 4096
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#define MIN_INLIER_PROB 0.1
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static INLINE RansacFunc get_ransac_type(TransformationType type) {
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switch (type) {
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case HOMOGRAPHY: return ransac_homography;
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case AFFINE: return ransac_affine;
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case ROTZOOM: return ransac_rotzoom;
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case TRANSLATION: return ransac_translation;
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default: assert(0); return NULL;
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}
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}
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// computes global motion parameters by fitting a model using RANSAC
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static int compute_global_motion_params(TransformationType type,
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double *correspondences,
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int num_correspondences, double *params,
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int *inlier_map) {
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int result;
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int num_inliers = 0;
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RansacFunc ransac = get_ransac_type(type);
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if (ransac == NULL) return 0;
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result = ransac(correspondences, num_correspondences, &num_inliers,
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inlier_map, params);
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if (!result && num_inliers < MIN_INLIER_PROB * num_correspondences) {
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result = 1;
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num_inliers = 0;
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}
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return num_inliers;
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}
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int compute_global_motion_feature_based(TransformationType type,
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YV12_BUFFER_CONFIG *frm,
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YV12_BUFFER_CONFIG *ref,
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double *params) {
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int num_frm_corners, num_ref_corners;
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int num_correspondences;
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double *correspondences;
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int num_inliers;
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int frm_corners[2 * MAX_CORNERS], ref_corners[2 * MAX_CORNERS];
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int *inlier_map = NULL;
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// compute interest points in images using FAST features
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num_frm_corners =
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fast_corner_detect(frm->y_buffer, frm->y_width, frm->y_height,
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frm->y_stride, frm_corners, MAX_CORNERS);
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num_ref_corners =
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fast_corner_detect(ref->y_buffer, ref->y_width, ref->y_height,
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ref->y_stride, ref_corners, MAX_CORNERS);
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// find correspondences between the two images
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correspondences =
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(double *)malloc(num_frm_corners * 4 * sizeof(*correspondences));
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num_correspondences = determine_correspondence(
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frm->y_buffer, (int *)frm_corners, num_frm_corners, ref->y_buffer,
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(int *)ref_corners, num_ref_corners, frm->y_width, frm->y_height,
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frm->y_stride, ref->y_stride, correspondences);
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inlier_map = (int *)malloc(num_correspondences * sizeof(*inlier_map));
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num_inliers = compute_global_motion_params(
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type, correspondences, num_correspondences, params, inlier_map);
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free(correspondences);
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free(inlier_map);
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return (num_inliers > 0);
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}
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