【opencv基礎】OpenCV從Mat中提取某些連續的行或列

前言

Opencv中可以調用函數提取某些連續的行或者列，Mat的rowRange和colRange可以獲取某些范圍內行或列的指針；

這兩個函數返回的是指向原矩陣內部位置的指針，類似於淺拷貝；

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數據某些間隔的行、列呢？？比如只提取奇數行或者偶數行，或者每隔3行提取數據。。。

分析：之前博主是由vector得到的Mat，所以可以在最開始得到Mat的過程中就間隔提取數據。

參考

1. OpenCV從Mat中提取某些行或列；

完