基于OpenCV的RGB和HSV色彩空间相互转换C++程序

帮助文档： http://docs.opencv.org/index.html

但凡图像处理软件，都会提供色相、饱和度、明度调整功能，比如常见的PS或者美图秀秀。在调整色相、饱和度、明度时，需要将每个像素点的rgb色彩空间转换到hsv色彩空间，然后做相应计算调整，最后在将计算结果转换回rgb颜色空间进行显示。有关概念及转换公式可以参考： http://zh.wikipedia.org/wiki/HSL%E5%92%8CHSV%E8%89%B2%E5%BD%A9%E7%A9%BA%E9%97%B4，

struct BGR
{uchar b;uchar g;uchar r;
};struct HSV
{int h;double s;double v;
};bool IsEquals(double val1 , double val2)
{return fabs(val1 - val2) < 0.001;
}// BGR(BGR: 0~255)转HSV(H: [0~360), S: [0~1], V: [0~1])
void BGR2HSV(BGR &bgr, HSV &hsv)
{double b, g, r;double h, s, v;double min, max;double delta;b = bgr.b / 255.0;g = bgr.g / 255.0;r = bgr.r / 255.0;if (r > g){max = MAX(r, b);min = MIN(g, b);}else{max = MAX(g, b);min = MIN(r, b);}v = max;delta = max - min;if (IsEquals(max, 0)){s = 0.0;}else{s = delta / max;}if (max == min){h = 0.0;}else{if (IsEquals(r, max) && g >= b){h = 60 * (g - b) / delta + 0;}else if (IsEquals(r, max) && g < b){h = 60 * (g - b) / delta + 360;}else if (IsEquals(g, max)){h = 60 * (b - r) / delta + 120;}else if (IsEquals(b, max)){h = 60 * (r - g) / delta + 240;}}hsv.h = (int)(h + 0.5);hsv.h = (hsv.h > 359) ? (hsv.h - 360) : hsv.h;hsv.h = (hsv.h < 0) ? (hsv. h + 360) : hsv.h;hsv.s = s;hsv.v = v;
}// HSV转BGR
void HSV2BGR(HSV &hsv, BGR &bgr)
{int h = hsv.h;double s = hsv. s;double v = hsv. v;double b = 0.0;double g = 0.0;double r = 0.0;int flag = (int)abs(h / 60.0);double f = h/60.0 - flag;double p = v * (1 - s);double q = v * (1 - f*s);double t = v * (1 - (1- f)*s);switch (flag){case 0:b = p;g = t;r = v;break;case 1:b = p;g = v;r = q;break;case 2:b = t;g = v;r = p;break;case 3:b = v;g = q;r = p;break;case 4:b = v;g = p;r = t;break;case 5:b = q;g = p;r = v;break;default:break;}int blue = int(b * 255);bgr.b = (blue > 255) ? 255 : blue;bgr.b = (blue < 0) ? 0 : bgr.b;int green = int(g * 255);bgr.g = (green > 255) ? 255 : green;bgr.g = (green < 0) ? 0 : bgr.g;int red = int(r * 255);bgr.r = (red > 255) ? 255 : red;bgr.r = (red < 0) ? 0 : bgr.r;
}int main()
{string imgName = "lena.jpg";Mat img = cv::imread(imgName);Mat tmp = img.clone();if (img.data == NULL){cout<< "Could not open or find the image"<<endl;return -1;}// 色彩空间转换>>自己实现int row = img.rows; int col = img.cols * img.channels(); uchar * pImg = NULL;BGR bgr; HSV hsv;for (int i = 0; i < row; i++) { pImg = img.ptr<uchar>(i);// 遍历时用img.at()效率会降很多, 很耗时 for (int j = 0; j < col; j+=3) {bgr.b = pImg[j]; bgr.g = pImg[j + 1]; bgr.r = pImg[j + 2]; BGR2HSV(bgr, hsv); hsv.h = hsv.h + 60;//调整色相 +60.取值范围为[0, 360) hsv.h = (hsv.h > 359) ? (hsv.h - 360) : hsv.h; hsv.h = (hsv.h < 0)   ? (hsv.h + 360) : hsv.h; HSV2BGR( hsv, bgr); pImg[j] = bgr.b; pImg[j + 1] = bgr.g; pImg[j + 2] = bgr.r; } } imshow("my", img);// 色彩空间转换>>调用OpenCVcvtColor(tmp, tmp, CV_BGR2HSV); vector<Mat> channels; split(tmp, channels); channels[0] += 30;// 调整色相 +30.这里没有做范围判断,opencv的h取值范围为[0, 180) merge(channels, tmp); cvtColor(tmp, tmp, CV_HSV2BGR); imshow("opencv", tmp); cv::waitKey();return 0;
}

ps：main()函数中同时提供了调用opencv函数实现的色相调整功能，主要使用了cvtColor()：色彩空间转换、split()：通道分离及merge():通道合并等函数。程序使用的opencv版本为210，运行上述程序还需添加opencv头文件引用以及配置相应lib文件。由于程序只是作为验证demo，所以写的有点乱、不够优化。