| // clang-format off |
| #include <stdlib.h> |
| #include "fast.h" |
| |
| |
| #define Compare(X, Y) ((X)>=(Y)) |
| |
| xy* aom_nonmax_suppression(const xy* corners, const int* scores, int num_corners, |
| int** ret_scores, int* ret_num_nonmax) |
| { |
| int num_nonmax=0; |
| int last_row; |
| int* row_start; |
| int i, j; |
| xy* ret_nonmax; |
| int* nonmax_scores; |
| const int sz = (int)num_corners; |
| |
| /*Point above points (roughly) to the pixel above the one of interest, if there |
| is a feature there.*/ |
| int point_above = 0; |
| int point_below = 0; |
| |
| *ret_num_nonmax = 0; |
| if(!(corners && scores) || num_corners < 1) |
| { |
| return 0; |
| } |
| |
| ret_nonmax = (xy*)malloc(num_corners * sizeof(xy)); |
| if (! ret_nonmax) |
| { |
| return 0; |
| } |
| |
| nonmax_scores = (int*)malloc(num_corners * sizeof(*nonmax_scores)); |
| if (! nonmax_scores) |
| { |
| free(ret_nonmax); |
| return 0; |
| } |
| |
| /* Find where each row begins |
| (the corners are output in raster scan order). A beginning of -1 signifies |
| that there are no corners on that row. */ |
| last_row = corners[num_corners-1].y; |
| row_start = (int*)malloc((last_row+1)*sizeof(int)); |
| if(! row_start) |
| { |
| free(ret_nonmax); |
| free(nonmax_scores); |
| return 0; |
| } |
| |
| for(i=0; i < last_row+1; i++) |
| row_start[i] = -1; |
| |
| { |
| int prev_row = -1; |
| for(i=0; i< num_corners; i++) |
| if(corners[i].y != prev_row) |
| { |
| row_start[corners[i].y] = i; |
| prev_row = corners[i].y; |
| } |
| } |
| |
| |
| |
| for(i=0; i < sz; i++) |
| { |
| int score = scores[i]; |
| xy pos = corners[i]; |
| |
| /*Check left */ |
| if(i > 0) |
| if(corners[i-1].x == pos.x-1 && corners[i-1].y == pos.y && Compare(scores[i-1], score)) |
| continue; |
| |
| /*Check right*/ |
| if(i < (sz - 1)) |
| if(corners[i+1].x == pos.x+1 && corners[i+1].y == pos.y && Compare(scores[i+1], score)) |
| continue; |
| |
| /*Check above (if there is a valid row above)*/ |
| if(pos.y > 0) |
| if (row_start[pos.y - 1] != -1) |
| { |
| /*Make sure that current point_above is one |
| row above.*/ |
| if(corners[point_above].y < pos.y - 1) |
| point_above = row_start[pos.y-1]; |
| |
| /*Make point_above point to the first of the pixels above the current point, |
| if it exists.*/ |
| for(; corners[point_above].y < pos.y && corners[point_above].x < pos.x - 1; point_above++) |
| {} |
| |
| |
| for(j=point_above; corners[j].y < pos.y && corners[j].x <= pos.x + 1; j++) |
| { |
| int x = corners[j].x; |
| if( (x == pos.x - 1 || x ==pos.x || x == pos.x+1) && Compare(scores[j], score)) |
| goto cont; |
| } |
| |
| } |
| |
| /*Check below (if there is anything below)*/ |
| if(pos.y >= 0) |
| if (pos.y != last_row && row_start[pos.y + 1] != -1 && point_below < sz) /*Nothing below*/ |
| { |
| if(corners[point_below].y < pos.y + 1) |
| point_below = row_start[pos.y+1]; |
| |
| /* Make point below point to one of the pixels belowthe current point, if it |
| exists.*/ |
| for(; point_below < sz && corners[point_below].y == pos.y+1 && corners[point_below].x < pos.x - 1; point_below++) |
| {} |
| |
| for(j=point_below; j < sz && corners[j].y == pos.y+1 && corners[j].x <= pos.x + 1; j++) |
| { |
| int x = corners[j].x; |
| if( (x == pos.x - 1 || x ==pos.x || x == pos.x+1) && Compare(scores[j],score)) |
| goto cont; |
| } |
| } |
| |
| ret_nonmax[num_nonmax] = corners[i]; |
| nonmax_scores[num_nonmax] = scores[i]; |
| num_nonmax++; |
| cont: |
| ; |
| } |
| |
| free(row_start); |
| *ret_scores = nonmax_scores; |
| *ret_num_nonmax = num_nonmax; |
| return ret_nonmax; |
| } |
| |
| // clang-format on |