合并OpenCV中的频道

Question

我需要从灰度图像中创建一个"红色"图像.我正在使用此代码:

void build_red(const cv::Mat& in, cv::Mat& out) {
    out = Mat::zeros(in.rows, in.cols, CV_8UC1);

    Mat zeros = Mat::zeros(in.rows, in.cols, CV_8UC1);
    Mat tmp;
    in.convertTo(tmp, CV_8UC1);

    vector<Mat> ch;
    ch.push_back(zeros);
    ch.push_back(zeros);
    ch.push_back(tmp);

    cout << "Using " << ch.size() << " channels" << endl;
    merge(ch, out);
} // build_red

有一些解释:

void build_red(const cv::Mat& in, cv::Mat& out) {

in是输入矩阵,输出.

out = Mat::zeros(in.rows, in.cols, CV_8UC1);

分配一些空间(可能没用,但是我尝试的一部分)

    Mat zeros = Mat::zeros(in.rows, in.cols, CV_8UC1);
    Mat tmp;
    in.convertTo(tmp, CV_8UC1);

创建一个大小相同的空矩阵,并将输入图像转换为单通道uchar.

    vector<Mat> ch;
    ch.push_back(zeros);
    ch.push_back(zeros);
    ch.push_back(tmp);

    cout << "Using " << ch.size() << " channels" << endl;
    merge(ch, out);

创建一个包含三个通道的向量,然后将它们合并为"out".

但是,当我运行代码时,我收到以下消息:

     Using 3 channels

以及以下例外:

OpenCV Error: Bad number of channels (Source image must have 1, 3 or 4 channels) 
in cvConvertImage, file /[...]/libs/OpenCV-2.4.0/modules/highgui/src/utils.cpp, 
line 611
terminate called after throwing an instance of 'cv::Exception'
what():  /[...]/libs/OpenCV-2.4.0/modules/highgui/src/utils.cpp:611: 
error: (-15) Source image must have 1, 3 or 4 channels in function cvConvertImage

请你帮助我好吗？从我没有经验的观点来看,图像的类型是相同的,并且通道的数量是正确的.

Answer 1

如果您有灰度图像,为什么要转换图像？

只需为蓝色和绿色创建两个相同大小的空矩阵.

并且您已将输出矩阵定义为1通道矩阵.您的输出矩阵必须包含至少3个通道.(蓝色,绿色和红色).蓝色和绿色将完全为空,并且您将灰度图像设置为输出图像的红色通道.

#include <opencv2/highgui/highgui.hpp> 
#include <stdio.h>
using namespace std;
using namespace cv;

int main()
{
    Mat img, g, fin_img;
    img = imread("Lenna.png",CV_LOAD_IMAGE_GRAYSCALE);
    vector<Mat> channels;

    g = Mat::zeros(Size(img.rows, img.cols), CV_8UC1);

    channels.push_back(g);
    channels.push_back(g);
    channels.push_back(img);

    merge(channels, fin_img);
    imshow("img", fin_img);
    waitKey(0);
    return 0;
}