三维目标检测中IoU的计算（C++实现）_c++计算目标检测iou

一、三维目标表示
世界坐标系下的三维目标有9个自由度，分别为三个自由度的平移量（中心点坐标）{x,y,z}，三自由度的旋转{roll, pitch, yaw}，三自由度的尺寸{length,width,height}。通常假设物体都是水平放置，所以roll = 0,pitch = 0;因此一个立方体可以表示为{x,y,z,0,0,yaw,len,wid,hei}。其中len、wid、hei分别是立方体长宽高的一半。
三、代码实现

bool bInBox(const vector<cv::Point2f> &vpBoxA, const cv::Point2f &p)
{
    std::vector<cv::Point2f> corners = vpBoxA;
    for(int i = 0; i<vpBoxA.size(); i++)   //01230123
        corners.push_back(vpBoxA[i]);

    std::vector< std::vector<double> > linesA;
    for(int i = 0; i<vpBoxA.size(); i++)
    {
        cv::Point2f p1 = corners[i];
        cv::Point2f p2 = corners[i+1];
        cv::Point2f p3 = corners[i+2];
        double a;
        if(p1.x - p2.x == 0)
            a = -(p1.y - p2.y)/0.0001;
        else
            a = -(p1.y - p2.y)/(p1.x - p2.x);

        double b = 1;
        double c = -a * p2.x - p2.y;
        double d = a*p3.x + b*p3.y + c;

        std::vector<double> line{a,b,c,d};
        linesA.push_back(line);
    }

    for(int i=0; i<linesA.size(); i++)
    {
        vector<double > l = linesA[i];
        double y = l[0] * p.x + l[1] * p.y +l[2];
        if(y * l[3] < 0)
            return false;
    }
    return true;
}

double InterSection_2D(const vector<cv::Point2f> &vpBoxA, const vector<cv::Point2f> &vpBoxB)
{
    double min_x, max_x, min_y, max_y;
    min_x = vpBoxA[0].x;
    max_x = vpBoxA[0].x;
    min_y = vpBoxA[0].y;
    max_y = vpBoxA[0].y;

    for(int i=1; i<vpBoxA.size(); i++)
    {
        cv::Point2f p = vpBoxA[i];
        if(p.x > max_x)
            max_x = p.x;
        if(p.x < min_x)
            min_x = p.x;
        if(p.y > max_y)
            max_y = p.y;
        if(p.y < min_y)
            min_y = p.y;
    }
    for(int i=0; i<vpBoxB.size(); i++)
    {
        cv::Point2f p = vpBoxB[i];
        if(p.x > max_x)
            max_x = p.x;
        if(p.x < min_x)
            min_x = p.x;
        if(p.y > max_y)
            max_y = p.y;
        if(p.y < min_y)
            min_y = p.y;
    }

    //将两个BBox的定点坐标最小值设置为0, 以防止有负数的产生
    vector<cv::Point2f> vpBoxAA = vpBoxA;
    vector<cv::Point2f> vpBoxBB = vpBoxB;

    //if(min_x < 0 && min_y < 0)
    for(int i=0; i<vpBoxA.size(); i++)
    {
        vpBoxAA[i].x = vpBoxAA[i].x - min_x;
        vpBoxAA[i].y = vpBoxAA[i].y - min_y;
        vpBoxBB[i].x = vpBoxBB[i].x - min_x;
        vpBoxBB[i].y = vpBoxBB[i].y - min_y;
    }

    int imax_x = (int)((max_x - min_x) * 10000);
    int imax_y = (int)((max_y - min_y) * 10000);

    double points_inA = 0, points_inB = 0, points_inAB = 0;
    srand((int)time(0));
    for(int i = 0; i<100000; i++)
    {
        int xx = rand()%(imax_x)+1;  //生成[1, imax_x]之间的整数
        int yy = rand()%(imax_y)+1;  //生成[1, imax_y]之间的整数

        cv::Point2f p((float)xx / 10000.0, (float)yy / 10000.0);
        if( bInBox(vpBoxAA, p) )
            ++points_inA;
        if( bInBox(vpBoxBB, p) )
            ++points_inB;
        if( bInBox(vpBoxAA, p) && bInBox(vpBoxBB, p) )
            ++points_inAB;
    }

    double iou = points_inAB / (points_inA + points_inB - points_inAB);
    //cout<<"points_inA : "<<points_inA<<",  points_inB: "<<points_inB<<" ,points_inAB: "<<points_inAB<<endl;
    return iou;
}
double CuboidIoU(const Eigen::MatrixXd &truth_poses, const Eigen::MatrixXd &landmark_poses)
{

    std::vector<cv::Point2f>  vground_points;
    std::vector<cv::Point2f>  vlandmark_points;
    if(1)  //通过坐标旋转求取groundtruth立方体中 2D-Boundbox四个顶点的坐标
    {
        double cen_x = truth_poses(0,0);
        double cen_y = truth_poses(0,1);
        double len = truth_poses(0,6);
        double wid = truth_poses(0,7);
        double yaw = truth_poses(0,5);

        double x, y, xx, yy;
        x = cen_x - len;
        y = cen_y - wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p0(xx, yy);

        x = cen_x - len;
        y = cen_y + wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p1(xx, yy);

        x = cen_x + len;
        y = cen_y + wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p2(xx, yy);

        x = cen_x + len;
        y = cen_y - wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p3(xx, yy);

        vground_points = {p0, p1, p2, p3};
    }

    if(1)//通过坐标旋转求取landmark中 2D-Boundbox四个顶点的坐标
    {
        double cen_x = landmark_poses(0,0);
        double cen_y = landmark_poses(0,1);
        double len = landmark_poses(0,6);
        double wid = landmark_poses(0,7);
        double yaw = landmark_poses(0,5);

        double x, y, xx, yy;
        x = cen_x - len;
        y = cen_y - wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p0(xx, yy);

        x = cen_x - len;
        y = cen_y + wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p1(xx, yy);

        x = cen_x + len;
        y = cen_y + wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p2(xx, yy);

        x = cen_x + len;
        y = cen_y - wid;
        xx = (x - cen_x)*cos(yaw) - (y - cen_y)*sin(yaw) + cen_x;
        yy = (x - cen_x)*sin(yaw) + (y - cen_y)*cos(yaw) + cen_y;
        cv::Point2f p3(xx, yy);

        vlandmark_points = {p0, p1, p2, p3};
    }

    double iou_2d = InterSection_2D(vlandmark_points, vground_points);
    double iou_3d = 0;
    if (iou_2d > 0) {
        double tru_minz = truth_poses(0, 2) - truth_poses(0, 8);
        double tru_maxz = truth_poses(0, 2) + truth_poses(0, 8);

        double land_minz = landmark_poses(0, 2) - landmark_poses(0, 8);
        double land_maxz = landmark_poses(0, 2) + landmark_poses(0, 8);

        if (land_maxz < tru_maxz && land_maxz > tru_minz) {
            double height_iou = (land_maxz - tru_minz) / (tru_maxz - land_minz);
            iou_3d = iou_2d * height_iou;
        } else if (tru_maxz < land_maxz && tru_maxz > land_minz) {
            double height_iou = (tru_maxz - land_minz) / (land_maxz - tru_minz);
            iou_3d = iou_2d * height_iou;
        }
    }

    return iou_3d;
}


void main(int argc, char **argv)
{
    Eigen::MatrixXd truth_poses(1,9);
    truth_poses<<-0.4875, -0.798913, -1.125, 0, 0, -1.27409, 0.240477, 0.235315, 0.375;
    Eigen::MatrixXd landmark_poses(1,9);
    landmark_poses<<-0.506616, -0.796303, -1.20499, 0, 0, -0.345443, 0.22,  0.22, 0.4 ;
    double iou_3d = CuboidIoU_once(truth_poses, landmark_poses);
    cout<<"the iou of two cuboid is: "<<iou_3d<<endl;
    return;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214