OpenCV:一种直接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通道之一.

例如,当图片被彩色化为"蓝色"时8UC1,强度为的灰度像素I = 50应成为强度的8UC3彩色像素BGR = (50, 0, 0).

例如,在Matlab中,可以使用两行代码简单地创建我要求的内容:

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中找不到类似的东西.

Answer 1

嗯,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);

或作为一种功能(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;
}

Answer 2

有一些特殊的功能 - 在contrib模块中从v2.4.5 开始在OpenCV中使用applyColorMap .有不同的颜色图可用: