c++ - OpenCV:一种简单明了的灰度图像着色方法

Question

什么是“着色”灰度图像的直接方法。通过着色，我的意思是将灰度强度值移植到新图像中的三个 R、G、B channel 之一。

例如，强度为 I = 50 的 8UC1 灰度像素应该变成强度为 BGR = ( 50, 0, 0) 当图片被着色为“蓝色”时。

例如，在 Matlab 中，我所要求的可以简单地用两行代码创建:

color_im = zeros([size(gray_im) 3], class(gray_im));
color_im(:, :, 3) = gray_im; 

但令人惊讶的是，我在 OpenCV 中找不到任何类似的东西。

Answer 1

好吧，同样的事情需要在 C++ 和 OpenCV 中做更多的工作:

// Load a single-channel grayscale image
cv::Mat gray = cv::imread("filename.ext", CV_LOAD_IMAGE_GRAYSCALE);

// Create an empty matrix of the same size (for the two empty channels)
cv::Mat empty = cv::Mat::zeros(gray.size(), CV_8UC1);

// Create a vector containing the channels of the new colored image
std::vector<cv::Mat> channels;

channels.push_back(gray);   // 1st channel
channels.push_back(empty);  // 2nd channel
channels.push_back(empty);  // 3rd channel

// Construct a new 3-channel image of the same size and depth
cv::Mat color;
cv::merge(channels, color);

或作为函数(压缩):

cv::Mat colorize(cv::Mat gray, unsigned int channel = 0)
{
    CV_Assert(gray.channels() == 1 && channel <= 2);

    cv::Mat empty = cv::Mat::zeros(gray.size(), gray.depth());
    std::vector<cv::Mat> channels(3, empty);
    channels.at(channel) = gray;

    cv::Mat color;
    cv::merge(channels, color);
    return color;
}