Opencv：如何从现有矩阵创建新矩阵有一些变化？ [英] Opencv: how to create new matrix from existing matrix with some changes?

问题描述

在OpenCV中，我有这样的矩阵：[3 4 2; 5 2 1; 6 7 9]，即3x3大小。现在我想把它改为3x1大小，并像这样：
[3 4 2 5 2 1 6 7 9]。但这不是我想要的，我的实际目标是在每个值之前和之后放置零，同时重复每个值三次。所以我的目标矩阵应该是这样：[0 3 3 3 0 0 4 4 4 0 0 2 2 2 0 0 5 5 5 0 0 2 2 2 0 0 1 1 1 0 0 6 6 6 0 0 7 7 7 0 0 9 9 9 0]。我为此写了以下代码：

in OpenCV, I have a matrix like this: [3 4 2; 5 2 1; 6 7 9], that is with 3x3 size. Now I want to change it into 3x1 size, and be like this: [3 4 2 5 2 1 6 7 9]. But this is not exactly what I want, my actual goal is to put zero before and after each value, at the same time repeat each value three times. So my goal matrix should be like this: [ 0 3 3 3 0 0 4 4 4 0 0 2 2 2 0 0 5 5 5 0 0 2 2 2 0 0 1 1 1 0 0 6 6 6 0 0 7 7 7 0 0 9 9 9 0 ]. I wrote the following code for this:

for ( int i = 0; i < 3; i ++ )
    {
        for ( int j = 0; j < 3; j ++ )
        {               
                for ( int m = k + 1; m < m + 3; m ++ )
                {
                    dstMat.col (m) = srcMat.at <int> ( i, j );

                }

                k = k + 5 ;                 
        }
    }

有更好的方法吗？特别是没有for循环，这是真的时间混乱。提前谢谢了。

Is there any better way for doing is? Especially without "for" loop, it is really time confusing. Many thanks in advance.

推荐答案

您可以使用 Mat :: reshape 将3x3矩阵转换为3x1。这样，你需要一个for循环，而不是两个，它是一个 O（1）操作。

You can use Mat::reshape to convert your 3x3 matrix to 3x1. This way you'll need one for loop instead of two, and it's an O(1) operation.

你可以通过使用ROI来省略下一个for循环：

you can omit the next for loop by using ROI:

  srcMat.reshape(0,1);
  for (int i =0; i < 9; i++)
    dstMat(cv::Range::all(), cv::Range(i*5+1, i*5+4)).setTo(srcMat.at<int>(i));

这将是全部。

这篇关于Opencv：如何从现有矩阵创建新矩阵有一些变化？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！