【opencv基础】OpenCV从Mat中提取某些连续的行或列

前言

Opencv中可以调用函数提取某些连续的行或者列，Mat的rowRange和colRange可以获取某些范围内行或列的指针；

这两个函数返回的是指向原矩阵内部位置的指针，类似于浅拷贝；

example

cv::Mat align_mean(cv::Mat mean, cv::Rect facebox, float scaling_x=1.0f, float scaling_y=1.0f, float translation_x=0.0f, float translation_y=0.0f)
{
    using cv::Mat;
    // Initial estimate x_0: Center the mean face at the [-0.5, 0.5] x [-0.5, 0.5] square (assuming the face-box is that square)
    // More precise: Take the mean as it is (assume it is in a space [-0.5, 0.5] x [-0.5, 0.5]), and just place it in the face-box as
    // if the box is [-0.5, 0.5] x [-0.5, 0.5]. (i.e. the mean coordinates get upscaled)
    Mat aligned_mean = mean.clone();
    Mat aligned_mean_x = aligned_mean.colRange(0, aligned_mean.cols / 2);
    Mat aligned_mean_y = aligned_mean.colRange(aligned_mean.cols / 2, aligned_mean.cols);
    aligned_mean_x = (aligned_mean_x*scaling_x + 0.5f + translation_x) * facebox.width + facebox.x;
    aligned_mean_y = (aligned_mean_y*scaling_y + 0.3f + translation_y) * facebox.height + facebox.y;
    return aligned_mean;
}

 引申

如果要提取Mat数据某些间隔的行、列呢？？比如只提取奇数行或者偶数行，或者每隔3行提取数据。。。

分析：之前博主是由vector得到的Mat，所以可以在最开始得到Mat的过程中就间隔提取数据。

参考

1. OpenCV从Mat中提取某些行或列；

完