运动可视化仪的结构

Question

我正在研究"运动结构"。我想，当涉及到运动的结构时，人们会看到《多视图几何》这本书。这是一本非常好的书，但我在那本书中发现了一些令人困惑的数据。在下面的代码中，有一个名为Populate point cloud的函数，它有两个参数pointcloud和pointcloud_RGB。我在pointcloud中有point3d类型的值，但我在那本书中没有找到任何关于pointcloud_RGB的信息，它突然出现在这个函数中，这个函数用于填充VEC3d-rgbv。有人能帮助谁看到这本书吗。

void PopulatePCLPointCloud(const vector<cv::Point3d>& pointcloud, 
  const std::vector<cv::Vec3b>& pointcloud_RGB = std::vector<cv::Vec3b>() 
) 
{ 
cout<<"Creating point cloud..."; 
cloud.reset(new pcl::PointCloud<pcl::PointXYZRGB>); 
for (unsigned int i=0; i<pointcloud.size(); i++) { 
// get the RGB color value for the point 
        cv::Vec3b rgbv(255,255,255); 
if (i < pointcloud_RGB.size()) { 
rgbv = pointcloud_RGB[i]; 
} 
        // check for erroneous coordinates (NaN, Inf, etc.) 
                if (pointcloud[i].x != pointcloud[i].x || 
                        pointcloud[i].y != pointcloud[i].y || 
                        pointcloud[i].z != pointcloud[i].z || 
#ifndef WIN32 
                        isnan(pointcloud[i].x) || 
                        isnan(pointcloud[i].y) || 
                        isnan(pointcloud[i].z) || 
#else 
                        _isnan(pointcloud[i].x) || 
                        _isnan(pointcloud[i].y) || 
                        _isnan(pointcloud[i].z) || 
                        false 
                        ) 
                { 
                        continue; 
                } 
pcl::PointXYZRGB pclp; 
pclp.x = pointcloud[i].x; 
pclp.y = pointcloud[i].y; 
pclp.z = pointcloud[i].z; 
// RGB color, needs to be represented as an integer 
uint32_t rgb = ((uint32_t)rgbv[2] << 16 | (uint32_t)rgbv[1] << 8 | 
(uint32_t)rgbv[0]); 
pclp.rgb = *reinterpret_cast<float*>(&rgb); 
cloud->push_back(pclp); 
} 
cloud->width = (uint32_t) cloud->points.size(); // number of points 
cloud->height = 1; // a list of points, one row of data 
//Create visualizer 
pcl::visualization::CloudViewer viewer ("Simple Cloud Viewer"); 
viewer.showCloud (cloud); 
                 cv::waitKey(0); 
                 return; 
}

Answer 1

我相信这是MasteringOpenCV第4章中的代码片段。我检查了整个项目，似乎这是中定义的某种错误pointcloud_RGB

const std::vector<cv::Vec3b>& pointcloud_RGB = std::vector<cv::Vec3b>()

并且除此之外不分配任何值；

rgbv = pointcloud_RGB[i];

这是在的条件下

if (i < pointcloud_RGB.size())

如果pointcloud_RGB为空，因此不能大于i，则程序永远不会进入此状态。这就是为什么它应该毫无问题地运行。

实点云是pcl::PointXYZRGB pclp;，这里用XYZ坐标+RGB值填充；

pcl::PointXYZRGB pclp; 
pclp.x = pointcloud[i].x; 
pclp.y = pointcloud[i].y; 
pclp.z = pointcloud[i].z; 
// RGB color, needs to be represented as an integer 
uint32_t rgb = ((uint32_t)rgbv[2] << 16 | (uint32_t)rgbv[1] << 8 | 
(uint32_t)rgbv[0]); 

当然，总有可能给作者发一封电子邮件，要求澄清。