| /* |
| * 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 <stdlib.h> |
| #include <stdio.h> |
| #include <memory.h> |
| #include <math.h> |
| #include <assert.h> |
| |
| #include "third_party/fastfeat/fast.h" |
| |
| #include "aom_dsp/aom_dsp_common.h" |
| #include "aom_dsp/flow_estimation/corner_detect.h" |
| #include "aom_mem/aom_mem.h" |
| #include "av1/common/common.h" |
| |
| #define FAST_BARRIER 18 |
| |
| size_t av1_get_corner_list_size() { return sizeof(CornerList); } |
| |
| CornerList *av1_alloc_corner_list() { |
| CornerList *corners = (CornerList *)aom_calloc(1, sizeof(CornerList)); |
| if (!corners) { |
| return NULL; |
| } |
| |
| corners->valid = false; |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_init(&corners->mutex, NULL); |
| #endif // CONFIG_MULTITHREAD |
| return corners; |
| } |
| |
| void compute_corner_list(const ImagePyramid *pyr, CornerList *corners) { |
| const uint8_t *buf = pyr->layers[0].buffer; |
| int width = pyr->layers[0].width; |
| int height = pyr->layers[0].height; |
| int stride = pyr->layers[0].stride; |
| |
| int *scores = NULL; |
| int num_corners; |
| xy *const frame_corners_xy = aom_fast9_detect_nonmax( |
| buf, width, height, stride, FAST_BARRIER, &scores, &num_corners); |
| |
| if (num_corners <= 0) { |
| // Some error occured, so no corners are available |
| corners->num_corners = 0; |
| } else if (num_corners <= MAX_CORNERS) { |
| // Use all detected corners |
| memcpy(corners->corners, frame_corners_xy, |
| sizeof(*frame_corners_xy) * num_corners); |
| corners->num_corners = num_corners; |
| } else { |
| // There are more than MAX_CORNERS corners avilable, so pick out a subset |
| // of the sharpest corners, as these will be the most useful for flow |
| // estimation |
| int histogram[256]; |
| av1_zero(histogram); |
| for (int i = 0; i < num_corners; i++) { |
| assert(FAST_BARRIER <= scores[i] && scores[i] <= 255); |
| histogram[scores[i]] += 1; |
| } |
| |
| int threshold = -1; |
| int found_corners = 0; |
| for (int bucket = 255; bucket >= 0; bucket--) { |
| if (found_corners + histogram[bucket] > MAX_CORNERS) { |
| // Set threshold here |
| threshold = bucket; |
| break; |
| } |
| found_corners += histogram[bucket]; |
| } |
| assert(threshold != -1 && "Failed to select a valid threshold"); |
| |
| int copied_corners = 0; |
| for (int i = 0; i < num_corners; i++) { |
| if (scores[i] > threshold) { |
| assert(copied_corners < MAX_CORNERS); |
| corners->corners[2 * copied_corners + 0] = frame_corners_xy[i].x; |
| corners->corners[2 * copied_corners + 1] = frame_corners_xy[i].y; |
| copied_corners += 1; |
| } |
| } |
| assert(copied_corners == found_corners); |
| corners->num_corners = copied_corners; |
| } |
| |
| free(scores); |
| free(frame_corners_xy); |
| } |
| |
| void av1_compute_corner_list(const ImagePyramid *pyr, CornerList *corners) { |
| assert(corners); |
| |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_lock(&corners->mutex); |
| #endif // CONFIG_MULTITHREAD |
| |
| if (!corners->valid) { |
| compute_corner_list(pyr, corners); |
| corners->valid = true; |
| } |
| |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_unlock(&corners->mutex); |
| #endif // CONFIG_MULTITHREAD |
| } |
| |
| #ifndef NDEBUG |
| // Check if a corner list has already been computed. |
| // This is mostly a debug helper - as it is necessary to hold corners->mutex |
| // while reading the valid flag, we cannot just write: |
| // assert(corners->valid); |
| // This function allows the check to be correctly written as: |
| // assert(aom_is_corner_list_valid(corners)); |
| bool aom_is_corner_list_valid(CornerList *corners) { |
| assert(corners); |
| |
| // Per the comments in the CornerList struct, we must take this mutex |
| // before reading or writing the "valid" flag, and hold it while computing |
| // the pyramid, to ensure proper behaviour if multiple threads call this |
| // function simultaneously |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_lock(&corners->mutex); |
| #endif // CONFIG_MULTITHREAD |
| |
| bool valid = corners->valid; |
| |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_unlock(&corners->mutex); |
| #endif // CONFIG_MULTITHREAD |
| |
| return valid; |
| } |
| #endif |
| |
| void av1_invalidate_corner_list(CornerList *corners) { |
| if (corners) { |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_lock(&corners->mutex); |
| #endif // CONFIG_MULTITHREAD |
| corners->valid = false; |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_unlock(&corners->mutex); |
| #endif // CONFIG_MULTITHREAD |
| } |
| } |
| |
| void av1_free_corner_list(CornerList *corners) { |
| if (corners) { |
| #if CONFIG_MULTITHREAD |
| pthread_mutex_destroy(&corners->mutex); |
| #endif // CONFIG_MULTITHREAD |
| aom_free(corners); |
| } |
| } |