OpenCV 获取 Mat 偶数行的副本

Question

我想获得 3 个通道的偶数 rows/cols，如下所示：

A = 1 0 1 0 1 0
    1 0 1 0 1 0
    1 0 1 0 1 0

result = 1 1 1
         1 1 1

如何使用 openCV 执行此操作？

提前致谢。

已编辑：

这是我使用的代码：

Mat img_object = imread(patternImageName);
Mat a;
for (int index = 0,j = 0; index < img_object.rows; index = index + 2, j++)
{
    a.row(j) = img_object.row(index);
}

但它抛出以下异常：

OpenCV Error: Assertion failed (m.dims >= 2) in Mat, file /build/buildd/opencv-2.4.8+dfsg1/modules/core/src/matrix.cpp, line 269
terminate called after throwing an instance of 'cv::Exception'

Answer 1

int j = 0;
for (int i = 0; i< A.size(); i+2)
{
    destMat.row(j) = (A.row(i));
    j++;
}

Answer 2

我终于可以做到了。这是解决方案

Mat img_object = imread(patternImageName);
Mat B;
for (int i = 0; i < img_object.cols; i += 2)
{
     B.push_back(img_object.col(i));
}
// now we got 1 large 1d flat (column) array with all the collected elements,
B = B.reshape(0,(img_object.cols/2));// 1 elem per channel, 3 rows.
B = B.t();          // transpose it
Mat result;
for (int i = 0; i < B.rows; i += 2)
{
     result.push_back(B.row(i));
}

Answer 3

您可以滥用 resize() 功能：

resize(bigImage, smallImage, Size(), 0.5, 0.5, INTER_NEAREST);

resize() 函数将创建新图像，其大小是原始图像的一半。

INTER_NEAREST表示小图的值将按"nearest neighbor"的方式计算。在这种特定情况下，这意味着小图像中位置 (1,2) 处的像素值将从大图像中位置 (2,4) 处的像素中获取。

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