/work/svt-av1/third_party/fastfeat/nonmax.c
Line | Count | Source |
1 | | // clang-format off |
2 | | #include <stdlib.h> |
3 | | #include "fast.h" |
4 | | |
5 | | |
6 | 0 | #define Compare(X, Y) ((X)>=(Y)) |
7 | | |
8 | | xy* svt_aom_nonmax_suppression(const xy* corners, const int* scores, int num_corners, int* ret_num_nonmax) |
9 | 0 | { |
10 | 0 | int num_nonmax=0; |
11 | 0 | int last_row; |
12 | 0 | int* row_start; |
13 | 0 | int i, j; |
14 | 0 | xy* ret_nonmax; |
15 | 0 | const int sz = (int)num_corners; |
16 | | |
17 | | /*Point above points (roughly) to the pixel above the one of interest, if there |
18 | | is a feature there.*/ |
19 | 0 | int point_above = 0; |
20 | 0 | int point_below = 0; |
21 | | |
22 | |
|
23 | 0 | if(num_corners < 1) |
24 | 0 | { |
25 | 0 | *ret_num_nonmax = 0; |
26 | 0 | return 0; |
27 | 0 | } |
28 | | |
29 | 0 | ret_nonmax = (xy*)malloc(num_corners * sizeof(xy)); |
30 | | |
31 | | /* Find where each row begins |
32 | | (the corners are output in raster scan order). A beginning of -1 signifies |
33 | | that there are no corners on that row. */ |
34 | 0 | last_row = corners[num_corners-1].y; |
35 | 0 | row_start = (int*)malloc((last_row+1)*sizeof(int)); |
36 | |
|
37 | 0 | for(i=0; i < last_row+1; i++) |
38 | 0 | row_start[i] = -1; |
39 | |
|
40 | 0 | { |
41 | 0 | int prev_row = -1; |
42 | 0 | for(i=0; i< num_corners; i++) |
43 | 0 | if(corners[i].y != prev_row) |
44 | 0 | { |
45 | 0 | row_start[corners[i].y] = i; |
46 | 0 | prev_row = corners[i].y; |
47 | 0 | } |
48 | 0 | } |
49 | | |
50 | | |
51 | |
|
52 | 0 | for(i=0; i < sz; i++) |
53 | 0 | { |
54 | 0 | int score = scores[i]; |
55 | 0 | xy pos = corners[i]; |
56 | | |
57 | | /*Check left */ |
58 | 0 | if(i > 0) |
59 | 0 | if(corners[i-1].x == pos.x-1 && corners[i-1].y == pos.y && Compare(scores[i-1], score)) |
60 | 0 | continue; |
61 | | |
62 | | /*Check right*/ |
63 | 0 | if(i < (sz - 1)) |
64 | 0 | if(corners[i+1].x == pos.x+1 && corners[i+1].y == pos.y && Compare(scores[i+1], score)) |
65 | 0 | continue; |
66 | | |
67 | | /*Check above (if there is a valid row above)*/ |
68 | 0 | if(pos.y > 0) |
69 | 0 | if (row_start[pos.y - 1] != -1) |
70 | 0 | { |
71 | | /*Make sure that current point_above is one |
72 | | row above.*/ |
73 | 0 | if(corners[point_above].y < pos.y - 1) |
74 | 0 | point_above = row_start[pos.y-1]; |
75 | | |
76 | | /*Make point_above point to the first of the pixels above the current point, |
77 | | if it exists.*/ |
78 | 0 | for(; corners[point_above].y < pos.y && corners[point_above].x < pos.x - 1; point_above++) |
79 | 0 | {} |
80 | | |
81 | |
|
82 | 0 | for(j=point_above; corners[j].y < pos.y && corners[j].x <= pos.x + 1; j++) |
83 | 0 | { |
84 | 0 | int x = corners[j].x; |
85 | 0 | if( (x == pos.x - 1 || x ==pos.x || x == pos.x+1) && Compare(scores[j], score)) |
86 | 0 | goto cont; |
87 | 0 | } |
88 | |
|
89 | 0 | } |
90 | | |
91 | | /*Check below (if there is anything below)*/ |
92 | 0 | if(pos.y >= 0) |
93 | 0 | if (pos.y != last_row && row_start[pos.y + 1] != -1 && point_below < sz) /*Nothing below*/ |
94 | 0 | { |
95 | 0 | if(corners[point_below].y < pos.y + 1) |
96 | 0 | point_below = row_start[pos.y+1]; |
97 | | |
98 | | /* Make point below point to one of the pixels belowthe current point, if it |
99 | | exists.*/ |
100 | 0 | for(; point_below < sz && corners[point_below].y == pos.y+1 && corners[point_below].x < pos.x - 1; point_below++) |
101 | 0 | {} |
102 | |
|
103 | 0 | for(j=point_below; j < sz && corners[j].y == pos.y+1 && corners[j].x <= pos.x + 1; j++) |
104 | 0 | { |
105 | 0 | int x = corners[j].x; |
106 | 0 | if( (x == pos.x - 1 || x ==pos.x || x == pos.x+1) && Compare(scores[j],score)) |
107 | 0 | goto cont; |
108 | 0 | } |
109 | 0 | } |
110 | | |
111 | 0 | ret_nonmax[num_nonmax++] = corners[i]; |
112 | 0 | cont: |
113 | 0 | ; |
114 | 0 | } |
115 | | |
116 | 0 | free(row_start); |
117 | 0 | *ret_num_nonmax = num_nonmax; |
118 | 0 | return ret_nonmax; |
119 | 0 | } |
120 | | |
121 | | // clang-format on |