1）void histogram_eq_demo(Mat& image);

2）void ColorInvert::histogram_eq_demo(Mat& image)
{
    Mat gray;
    cvtColor(image, gray, COLOR_BGR2GRAY);
    imshow("灰度图像", gray);
    Mat dst;
    equalizeHist(gray, dst);
    imshow("直方图均衡化演示", dst);
}

3)显示如下：